UA08 R99 Radio Principles Alcatel Lucent

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UTRANUA08 9300 W-CDMA R99 Radio PrinciplesStudent GuideTMO18246_V2.0-SG Edition 1

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Course outline

4. Topic/Section is Positioned Here




1. W-CDMA R99 Radio Principles1. UTRAN System Description2. WCDMA for UMTS3. UTRAN Scenario4. MBMS Radio Principles5. Glossary

Welcome to UTRANUA08 9300 W-CDMA R99 Radio Principles

1. W-CDMA R99 Radio Principles

1. UTRAN System Description

2. WCDMA for UMTS

3. UTRAN Scenario

4. MBMS Radio Principles

5. Glossary




Course objectives

Upon completion of this course, you should be able to:

describe WCDMA principles for UMTS describe mobile system standards evolution describe UMTS services, new capacity figures and service architecture draw the UTRAN architecture with the protocol stack define a Radio Resource in 3G and describe WCDMA principles for UMTS describe how the user can access to the network and asks for a 3G service describe UTRAN functions and state protocols.

UTRANUA08 9300 W-CDMA R99 Radio Principles

Upon completion of this course, you should be able to:

describe WCDMA principles for UMTS

describe mobile system standards evolution

describe UMTS services, new capacity figures and service architecture

draw the UTRAN architecture with the protocol stack

define a Radio Resource in 3G and describe WCDMA principles for UMTS

describe how the user can access to the network and asks for a 3G service

describe UTRAN functions and state protocols.

Your feedback is appreciated!Please feel free to Email your comments to:

[email protected]

Please include the following training reference in your email:TMO18246_V2.0-SG Edition 1

Thank you!

Copyright © 2012 Alcatel-Lucent. All Rights Reserved.TMO18246_V2.0-SG-UA08-Ed1 Module 1.1 Edition 1

Section 1 · Module 1 · Page 1

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Module 1UTRAN System Description

TMO18246_V2.0-SG-UA08-Ed1 Module 1.1 Edition 1

Section 1W-CDMA R99 Radio Principles


TMO18246_V2.0-SG Edition 1



UTRAN · UA08 9300 W-CDMA R99 Radio PrinciplesW-CDMA R99 Radio Principles · UTRAN System Description1 · 1 · 2

COPYRIGHT © ALCATEL-LUCENT 2012. ALL RIGHTS RESERVED.

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Edition Date Author Remarks

01 YYYY-MM-DD Last name, first name First edition





Module objectives

Upon completion of this module, you should be able to:

Draw the UTRAN architecture with the protocol stack (radio and Iu) of each network element and to define the channels generated by these protocols.





Module objectives [cont.]






Table of contents

Switch to notes view!Page

1 Logical Architecture 71.1 UTRAN Situation & Core Network in 3GPP R4 81.2 UTRAN Logical Architecture 91.3 Interfaces 101.4 Network Element Function 112 Network Protocols 132.1 Protocols in UTRAN 142.2 UTRAN Logical Architecture 152.3 Hybrid Iub logical architecture 162.4 Native IP Iub logical architecture 172.5 NodeB synchronisation for all IP 182.6 IP Iur logical architecture 192.7 IP IU-PS logical architecture 202.8 IP Iu-CS logical architecture 212.9 O&M flow architecture 223 Protocol Stacks 233.1 Protocols in UTRAN 243.2 General model 253.3 Iub Protocol Stacks 263.4 I-BTS O&M Plane 273.5 Iur Protocol Stacks 283.6 Iu-PS Protocol Stacks 293.7 Iu-CS Protocol Stacks 303.8 IU- CS – RTP/RTCP Protocol 314 Radio Channels 324.1 Global Situation 334.2 RAB Presentation 344.3 Radio Channels, Protocols & Network Elements 354.4 Radio Bearers 364.5 Channel Types 374.6 Channels Vs. Interfaces 384.7 Uu Protocol Layers 394.8 Physical Layer Architecture 404.9 Radio Interface Distributed Architecture 414.10 Logical Channels 424.11 Why Transport Channels? 444.12 Structure of a Transport Channel 454.13 Transport Channels: Example 474.14 Transport Channels 484.15 Common Transport Channels 494.16 Dedicated Transport Channels 524.17 Mapping Logical / Transport Channels 534.18 Physical Channels 554.19 Physical Channel List 564.20 Downlink 574.21 Uplink 584.22 Physical Channels: Structure 595 UTRAN Radio Protocols 605.1 Radio protocol stack 615.2 Radio Resource Control (RRC) 625.3 PDCP and BMC Protocols 635.4 Radio Link Control (RLC) 645.5 Medium Access Control (MAC) 655.6 The Physical Layer 666 Radio Resource control Layer 67





Table of contents [cont.]


6.1 RRC Main Functions 686.2 RRC States 697 Exercises 707.1 MAC protocol 71




1 Logical Architecture

Section @@SECTION · Module @@MODULE · Page 7






1.1 UTRAN Situation & Core Network in 3GPP R4

Core Network

PS-CN

Access Network

Iu-PS

External Networks

HLR

PSTN

IN network

UTRAN

RNCRNC

Node B

PDN

CS Links

PS Links

Gb

Backbone

iGGSiGGSNN

SGSNGSMBSS

BSC

BTS PCU

CS-CN

MSC Server

MGW GMSCIu-CS

A Public Land Mobile Network (PLMN) is composed of 2 main parts:

The Access Network (AN) provides the radio interface and radio resource management for mobile communications toward the Core Network (CN).

The Core network is in charge of User Equipment (UE) Mobility (MM) and Session (SM) management. It also deals with the external networks for voice call establishment or data session establishment.

The UMTS Terrestrial Radio Access Network (UTRAN) is the UMTS Access Network; it’s composed of Node Bs and Radio Network Controllers (RNCs).

An ATM switch interfaces the UTRAN and the CN:

• Iu-CS interface for the Circuit Switched Core Network (CSCN).

• Iu-PS interface for the Packet Switched Core Network (PSCN).

The PLMN connects specifically to the Public Switched Telephone Network (PSTN) for voice or to the Packet Data Network (PDN) for data.

The CN includes the Intelligent Network (IN) for value-added services.

Example of services:

For voice:

• Voice Call Prepaid Service

• SMS service

• Call Waiting

Fisayo

Highlight






1.2 UTRAN Logical Architecture

Core Network

UTRAN

UE

Iub Iub

Iu-CS Iu-PS

Iur

Uu Interface

RNS

CS-CN PS-CN

RNC RNC

Node B Node B

UEs

CN

2 separated domains: Circuit Switched (CS) and Packet Switched (PS) which reuse the infrastructure of GSM and GPRS respectively.

UTRAN

new radio interface: CDMA

new transmission technology: ATM

CN independent of AN

The specificity of the access network due to mobile system should be transparent to the core network, which may potentially use any access technique.

Radio specificity of the access network is hidden to the core network.

UE radio mobility is fully controlled by UTRAN.

Some correspondences with GSM:

CN NSS Uu Um

UTRAN BSS Iub A-bis

RNC BSC Iur no equivalent

Node-B BTS Iu-CS A

UE MS Iu-PS Gb

Fisayo

Highlight






1.3 Interfaces

Open Interfaces:

• The function of the Network Elements have been clearly specified by the 3GPP.• Their internal implementation issues are open for the manufacturer• All the interfaces have been defined in such a detailed level that the equipment at the endpoints can be from different manufacturers.

• “Open Interfaces” aim at motivating competition between manufacturers.

Physical implementation of Iu interfaces

•Each Iu Interface may be implemented on any physical connection using any transport technology, mainly on E1 (cable), STM1 (Optic fiber) and micro-waves.•ATM will be provided in the 3GPP R4 release and IP is for the 3GPP R6

A manufacturer can produce only the Node-B (and not the RNC). This is not possible in GSM (A-bis is a proprietary interface)

The Iur physical connection can go through the CN using common physical links with Iu-CS and Iu-PS. However there is a direct logical connection between the 2 RNCs: the Iur information is not handled by the CN.






1.4 Network Element Function

RNC: Radio Network Controller

It is the intelligent part of the UTRAN:

- Radio resource management (code allocation, Power Control, congestion control, admission control)- Call management for the users- Connection to CS and PS Core Network- Radio mobility management

Iub IubIur

RNS

Node B Node B

RNC RNC

An RNS (Radio Network Subsystem) contains one RNC (Radio Network Controller) and at least one Node-B.

The RNC takes a more important place in UTRAN than the BSC in the GSM BSS. Indeed RNC can perform soft HO, while in GSM there is no connection between BSCs and only hard HO can be applied.

Fisayo

Highlight






1.4 Network Element Function [cont.]

Node-B

A Node-B can be considered, as first approximation, like a transcoder between the data received by antennas and the data in the ATM cell on the Iub.

- Radio transmission and reception handling- Involved in the mobility management- Involved in the power control

Iub

RNC

Node B

ATM Transport Technology

An RNS (Radio Network Subsystem) contains one RNC (Radio Network Controller) and at least one Node-B.

A Node-B is also more complex than the GSM BTS, because it handles softer HO.

Controlling RNC (CRNC): a role an RNC can take with respect to a specific set of Node-Bs (ie those Node-Bs belonging to the same RNS). There is only one CRNC for any Node-B. The CRNC has the overall control of the logical resources of its Node-Bs

Fisayo

Highlight

Fisayo

Highlight




2 Network Protocols






2 Network Protocols

2.1 Protocols in UTRAN

Uu Interface

Core Network

RNC RNC

Node B

Iub

Iu

Iur

Iu Protocols

The Iu protocols Used to exchange data (traffic

and signaling) between RNCs, Node Bs and the Core Network.

Radio Protocols

The Radio protocols Used to process the data sent on

the air and for the signaling between UTRAN and the UEs

NAS Signaling Signaling between a UE and

the Core Network. Typically, the Authentification

and the Location

NAS Signaling

Iu Protocols :

RANAP: Radio Access Network Application Protocol,

RNSAP: Radio Network Sub-system Application Protocol,

NBAP: Node B Application Protocol,

ALCAP is a generic name for the signalling protocols of the Transport Network Control

Plane used to establish/release Data Bearers.

It makes establishment/release of Data Bearers on request of the Application Protocol.

Radio Protocols :

RRC: Radio Resource Control

RLC: Radio Link Control

MAC: Medium Access Control

NAS Signaling :NAS refers to higher layers (3 to 7). Entities of this part will exchange tele-services and bearer services





2 Network Protocols

2.2 UTRAN Logical Architecture

Iub

Iu-PS

Iub

Iub

Iur

Iu-BC

Itf-R

Itf-B

(SAS)

Iu-CS

ATM BackboneATM Backbone

IP Backbone IP Backbone

OMC

CBC

SAS

MSC

MSC

MGW

MGWMGW

MGW

SGSN

Itf-R

Itf-B

RNC RNCSGSN

ATM NB

Hybrid NB

IP NB

CBC

Last Mile

UTRAN Core Network

GGSN

The scope of IP Transport in UTRAN is intended to replace the ATM transport network (AAL2/ATM or AAL5/ATM) by an IP transport network to reduce the transmission cost.

The radio network layer remains unchanged in the control plane (RANAP, RNSAP, NBAP), except that the transport layer information provided in NBAP/RNSAP/RANAP is changed, and in the user plane (Iu / Iur / Iub UP Frame Protocols). ALCAP disappears in the transport network control plane.

After the introduction in UA06 of an hybrid ATM / IP transport on Iub (iBTS only) and a pure IP transport on Iu-PS, it is added in UA07:

· Full IP transport on Iub: the existing ATM interface is removed and all the traffic (User Plane and Control Plane) is transported over an IP/Ethernet interface

· IP transport on Iu-CS: between the RNC and the MSC, and between the RNC and the MGW in NGN architecture

· IP transport on Iur: between two RNC

· Pure IP transport on Itf-R and Itf-B : the OMC can be connected only to the IP backbone

· IP transport on Iu-BC: between the RNC and the CBC

Moreover, a full mixity between ATM and IP transport is supported in UA07:

· A mix of ATM Nodes B, Hybrid Nodes B and Full IP Nodes B are supported on the same RNC

· A mix of ATM and IP is supported on Iu/Iur : Iu-PS over IP / Iu-CS over ATM or some Iurs over ATM and other Iurs over IP

· A mix of ATM and IP is supported on Iu-CS/Iu-PS in case of Iu-Flex

· The OMC can be connected either to the ATM backbone (via an IP over ATM access node) or to the IP backbone,

· The O&M flow from RNC to OMC can be “In band” or “Out of Band” (using an Ethernet port of a dedicated card).

Note that the Iu-PC interface is not supported over IP in UA07 as the Standalone AssistedGPS SMLC (SAS) is integrated in the RNC in UA07 (see FRS 34123). That means that Iu-PC over ATM is still supported on a mix ATM/IP RNC but integrated SMLC server is needed in case of a Full IP RNC.





2 Network Protocols

2.3 Hybrid Iub logical architecture

OAM flow on ATM

Signaling flow on ATM

R99 + Common channels + HSPA Streaming User plane on ATM

HSPA Interactive / Background User plane on IP

RNC

OMC

Hybrid BTS

Hybrid BTS

Ethernet Link

E1/T1 Links

Ethernet Link

IP Network:Several

DSCP

ATM Network:Several ATM VCs

GE Link

STM1 Link

ATM on STM1

IP on VLAN/GE VR

Hybrid Iub means support of hybrid ATM / IP transport on Iub interface:

· ATM being used for control plane (NBAP, ALCAP), Node B O&M and R99 user plane. ATM also carries HSDPA streaming and SRB on HSPA.

· IP being used for HSDPA and HSUPA user plane traffic with interactive/background traffic class.

In UA6, VLANs are introduced in the RNC to separate, at ethernet level, different flows on the same physical Gigabit Ethernet Port : one VLAN is dedicated to Iub user plane.

In UA07, VLAN is introduced in the iBTS.

QoS differentiation is ensured by DiffServ at IP level and, optionally, by Priority Bits at Ethernet level.

Hybrid Iub is supported only on iBTS (from UA06), equipped with xCCM. Hybrid Iub is NOT supported on iBTS equipped with iCCM, on oneBTS, on micro / pico Node B.





2 Network Protocols

2.4 Native IP Iub logical architecture

OMC

PTP server

IP Node

FE/GE Link

GE Link

User Plane

Control PlaneOAM flowSynchro flow

0 or 1 VLAN0 or 1 VLAN0 or 1 VLAN

0 or 3 VLANs1 or 3 IP adresses

IP Network:DSCP mandatoryVLAN/pbits optional

RNC

Native IP Iub means support of IP transport only on Iub interface both for Control Plane, User Plane and Node B O&M flows, ATM is no more used.

The Control Plane consists in NBAP signaling messages only, as ALCAP is not needed any more.

The User Plane consists in different traffic types having different QoS requirements.

The Node B O&M flows may go directly from OMC to Node B.

These different data flows (control, user, O&M) may be separated by using different IP addresses and also by different VLANs at RNC side and at Node B side.

QoS differentiation is ensured by DiffServ at IP level and, optionally, by Priority Bits at Ethernet level.

At Ethernet level, VLANs can be used to separate different flows (User Plane, Control Plane, O&M flows) on the same physical Ethernet Port.

For synchronization, the Node B needs an interface with an external PTP server.

.





2 Network Protocols

2.5 NodeB synchronisation for all IP

Iub

Node B

Node B

RNC

IP Transport

IEEE1588v2 serverclock

Synchframes

Node B

GPSreceiver

Cell sitegateway

E1 linkfor synchro

This feature provides support for synchronisation of all IP NodeB inplementation by introducing the following options:

· Packet synchronisation based on IEEE1588v2( External IEEE1588v2 server for synchronization)

or alternative synch method:

· GPS synchronisation

· E1/T1 synchronisation (not used for traffic – only synchronisation)

Up until UA7.1, a BTS provides only E1/T1 or E3/T3 or STM1/OC-3 connectivity and therefore uses the corresponding line timing to extract an 8 kHz signal being used for OMA supervision.

In UA07.1 the native IP IuB feature is introduced, which allows the operator to carry all IuB traffic over Ethernet transport. With the introduction of this feature BTS systems supporting Ethernet backhaul won’t have E1/T1 or E3/T3 or STM1/OC-3 connectivity and hence no 8 kHz signal can be derived anymore from the network clock. To recover an 8 kHz signal with sufficient accuracy for OMA supervision the IEEE 1588v2 Precision Timing Protocol (PTP) is implemented in the BTS to synchronize to a PTP time server thereby allowing an 8 kHz signal to be generated internal to the BTS.

The 8 kHz clock being generated via an onboard oscillator of +/- 25 ppm frequency accuracy needs frequency adjustment to get a long-term frequency accuracy with a Maximum Time Interval Error (MTIE) of ~ 400 ppb @ 4h. As only frequency adjustment is needed the OneBTS supports only a reduced PTP functionality (e.g. delay measurement of Sync messages is not needed).

StandardsIEEE P1588 D2.2 Draft Standard for a Precision Clock Synchronization Protocol for Networked

Measurement and Control Systems





2 Network Protocols

2.6 IP Iur logical architecture

VR

RNC

CPUP

GE LinkGE Link

Peer RNC

IP Network

Refer to IuB arch.

UserPlane (UP)

Control Plane (CP)

Node B

RNCs may be connected to the ATM backbone or to the IP backbone or to both. However:

On Iu-R, Control and User plane stacks must be both either IP or ATM; i.e. no mix and match of ATM Control and IP User plane or vice versa.

At IP level, DiffServ is used for QoS differentiation.

At Ethernet level, VLANs can be used to separate different flows (User Plane, Control Plane) on a single VR associated with a physical Gigabit Ethernet Port.





2 Network Protocols

2.7 IP IU-PS logical architecture

STM1 Link

GE Link

IP/ATM

IP/VLAN/G

IP Network:Several

DSCP


GGSN

GGSN

GGSN

1 Iu flexdomain

RNC

VR

SGSN

SGSN

In UA06, the RNC can be connected to the SGSN through the CN IP backbone and, optionally, it can be connected to the GGSN using a direct GTP tunnel for the User Plane without any impact on RNC side nor on configuration since the SGSN is responsible for providing the User Plane address of the GGSN by Control Plane signaling.

On Iu-PS, a mix of ATM transport and IP transport is supported, even in the same pool in case of Iu Flexibility configuration, but both Control Plane and User plane stacks must be either IP or ATM, e.g. no mix and match of ATM Control Plane and IP User plane or vice versa.

Taken into account also the option to have a direct tunnel between RNC and GGSN, the above RNC connectivity shall be supported.





MGW

MSC server

MGW

MSC

MSC

2 Network Protocols

2.8 IP Iu-CS logical architecture

RNC

VRSTM1

Link

GE Link

IP/VLAN/GE

IP Network:Several

DSCP

1 Iu flexdomain


In a mixed ATM / IP UTRAN, each network element may be connected either to the ATM backbone or to the IP backbone.

RNCs may be connected to the ATM backbone or to the IP backbone or to both.

MSC/MGW may be either connected on the ATM backbone or on the IP backbone, even in the same pool in case of Iu Flexibility configuration.

On Iu-CS, Control and User plane stacks must be both either IP or ATM, e.g. no mix and match of ATM Control and IP User plane or vice versa.

Taken into account both NGN and non-NGN configurations in CS Core Network the above RNC connectivity with CN nodes shall be supported.





2 Network Protocols

2.9 O&M flow architecture

RNC

STM1 ports ofSTM1 card

Ethernet port of CP card

Ethernet ports of GE card

RNC

STM1 ports ofSTM1 card

Ethernet port of CP card

Ethernet ports of GE card

OAM flow (itfr)

OAM flow (itfb)

Teleco flow over IP

Native IPBTS

Eth. Port

Native IPBTS

Eth. Port

OMCEth. Port

IP Network

IP Network

OMCEth. Port

The O&M topologies supported with Native IP Node B, i.e. the possible paths for the O&M Node B flow (itfb) and for the RNC O&M flow (itfr) are different.

The supported topologies are the result of the combinations of the following rules:

1. The telecom flow of a Native IP Node B is always getting in the RNC on an Ethernet port of the GigaBit Ethernet card.

2. The O&M flow of a Native IP Node B (itfb) can either:

Not go through the RNC.

Get in the RNC on an Ethernet port of the GigaBit Ethernet card.

3. The O&M flow between the RNC and the OMC can either:

Get in the RNC via the Ethernet port of the CP card,

Get in the RNC on an Ethernet port of the GigaBit Ethernet card.

Get in the RNC via a STM1/OC3 port of the STM1/OC3 card (in case of ATM connection).

From OMC-R side a mix of the previous case per RNS is possible.

4. An OMC can be connected to:

an ATM backbone (via a POC) for Itf-r and itf-b;

an IP backbone for Itf-r and itf-b, i.e. the O&M does not go through ATM but by Ethernet,

a mix of the two previous cases per RNS.

The RNC is the bridge from IP/atm/STM1/OC3 to IP/GE ONLY for the O&M itfb flow.

Another transport node can also provide this ATM to IP bridge role.




3 Protocol Stacks






3 Protocol Stacks

3.1 Protocols in UTRAN

Uu Interface

Core Network

RNC RNC

Node B

Iub

Iu

Iur

Iu Protocols

The Iu protocols Used to exchange data (traffic

and signaling) between RNCs, Node Bs and the Core Network.

Radio Protocols

The Radio protocols Used to process the data sent on

the air and for the signaling between UTRAN and the UEs

NAS Signaling Signaling between a UE and

the Core Network. Typically, the Authentification

and the Location

NAS Signaling

Iu Protocols :

RANAP: Radio Access Network Application Protocol,

RNSAP: Radio Network Sub-system Application Protocol,

NBAP: Node B Application Protocol,

ALCAP is a generic name for the signalling protocols of the Transport Network Control

Plane used to establish/release Data Bearers.

It makes establishment/release of Data Bearers on request of the Application Protocol.

Radio Protocols :

RRC: Radio Resource Control

RLC: Radio Link Control

MAC: Medium Access Control

NAS Signaling :

NAS refers to higher layers (3 to 7). Entities of this part will exchange tele-services and bearer services





3 Protocol Stacks

3.2 General model

DataStream(s)

ApplicationProtocol

ALCAP

SignalingBearer(s)

Radio NetworkLayer

User Plane

TransportLayer

TransportNetwork

Control Plane

Radio Network Control Plane

Physical Layer

The same general protocol model is applied for all Iu interfaces:

1. What is the purpose of the separation between the Radio Network Layer and the Transport Network Layer?

2. Why is ALCAP necessary?

Transport Network User Plane

SignalingBearer(s)

DataBearer(s)

Transport Network Control Plane






3 Protocol Stacks

3.3 Iub Protocol Stacks

Iub FPNode BApplication Part(NBAP)

UDP

IP

SCTP

IP

ALCAP

SSCF-UNI

SSCOP

AAL5

ATM ATM ATM

AAL5 AAL2

SSCOP

SSCF-UNI

Q.2150.2

Q.2630.2

Data Link Layer Data Link Layer

Radio NetworkLayer

User Plane

TransportLayer

TransportNetwork

Control Plane

Radio Network Control Plane

Physical Layer

For IP transport of the Iub user plane over Ethernet, the 3GPP requirements, in TS 25426, are:

· UDP over IP shall be supported as the transport for DCH data streams on Iub

· The transport bearer is identified by UDP port number and IP address (source UDP port number, destination UDP port number, source IP address, destination IP address).

· The source IP address and destination IP address exchanged via Radio Network Layer on the Iur/Iub interface shall use the NSAP structure.

· IP Differentiated Services code point marking shall be supported. The mapping between traffic categories and Diffserv code points shall be configurable by O&M. Traffic categories are implementation-specific and may be determined from the application parameters.

The bearer identifiers (UDP port number and IP address) are exchanged between RNC and Node B at each Radio Link Setup via NBAP signaling messages.

The DSCP is determined by the RNC and given to the Node B at each Radio Link Setup via NBAP signaling messages.

For IP transport of the Iub Control plane over Ethernet, the 3GPP requirements, in TS 25432, are:

· SCTP over IP shall be supported as the transport for NBAP signaling bearer on Iub Interface

· The checksum method specified in RFC 3309 shall be used instead of the method specified in RFC 2960

· Each signaling bearer between the RNC and Node B shall correspond to one single SCTP stream in UL and one single SCTP stream in DL direction, both streams belonging to the same SCTP association.

· IP Differentiated Services code point marking shall be supported. The DiffServ Code Point may be determined from the application parameters.

· A RNC equipped with the SCTP stack option shall initiate the INIT procedure for establishing association (new in Rel 7)

· Multi-homing is not required





3 Protocol Stacks

3.4 I-BTS O&M Plane

The protocols for Native iBTS IP

DHCP port numbers: Well Known UDP Port Numbers 67 (client) 68 (server)

Ethernet

IP

TCP UDP ICMP ARP

SEPE DHCP Etc. Any for site

LANFTP Etc. Any for site

LAN Radius RIP V2

The figure above does not intend to describe all the O&M protocols, which are supported for Native IP iBTS, because the list is open (due to Site Lan support, for example). It intends to list the main O&M protocols, and also to illustrate that it is not possible to identify an O&M flow, based on the fact that it is over TCP.





3 Protocol Stacks

3.5 Iur Protocol Stacks

ATM

SSCF-NNI

SSCOP

AAL5

M3UA

IP

User PlaneControl Plane



Radio NetworkLayer

TransportNetworkLayer

MTP3-3

SCTP

SCCP

RNSAP

Iu-R Data Stream(s)

AAL2

ATM Ethernet

Physical Layer Physical Layer

Unchanged or refused New or modified

UDP

IP

Ethernet

AAL5

SSCOP

MTP3-B

Q.2150.1

Q.2630.2

Transport Network Control

Plane

ATM

Physical Layer

SSCF-NNI

For Iur User Plane the transport bearer is identified by the UDP port number and the IP address (source UDP port number, destination UDP port number, source IP address, destination IP address).

The source and destination IP addresses and the associated UDP port numbers are exchanged via RNSAP and shall use the NSAP structure.

There may be one or several IP addresses in the RNC. The packet processing function in the RNC sends packets of a given RAB to the IP address / UDP port which was associated to that particular RAB when establishing the connection via RNSAP (either by RNC itself or by peer RNC).





3 Protocol Stacks

3.6 Iu-PS Protocol Stacks

ATM

User Plane


Plane

Control Plane


Transport Network

User Plane

Radio NetworkLayer


SCCP

RANAP

Iu UP Protocol Layer

ATM Ethernet



IP

UDP

IP

AAL5

GTP-U GTP-U

UDP

Ethernet

SSCF-NNI

SSCOP

MTP3-B M3UA

IP

AAL5

SCTP

M3UA

IP

SCTP

Not support

In this release only IPv4 is supported.

The transport bearer is identified by the GTP TEID and the IP address (source GTP TEID, destination GTP

TEID, source IP address, destination IP address).

The IP addresses and GTP TEID are exchanged between RNC and SGSN by using RANAP protocol.

There may be one or several IP addresses in the RNC and in the CN.





3 Protocol Stacks

3.7 Iu-CS Protocol Stacks

ATM

SSCF-NNI

SSCOP

AAL5AAL5

SSCOP

MTP3-B

Q.2150.1

Q.2630.2

M3UA

IP

User Plane


Plane

Control Plane



Radio NetworkLayer


MTP3-3

SCTP

SCCP

RANAP

Iu UP Protocol Layer

AAL2

ATM ATM Ethernet

Physical LayerPhysical Layer Physical Layer


UDP

IP

Ethernet

RTP/RTCP

SSCF-NNI

The transport bearer is identified by the UDP port number and the IP address (source UDP port number,

destination UDP port number, source IP address, destination IP address).

The source IP address and destination IP address are exchanged via RANAP and shall use the NSAP

structure.

There may be one or several IP addresses in the RNC and in the CN.





3 Protocol Stacks

3.8 IU- CS – RTP/RTCP Protocol

Ethernet

UDP

IP

RTP/RTCP

Iu/UP

RTP (Real time protocol) provides end-to-end network transport functions suitable for applications

transmitting real-time data, such as audio, video or simulation data, over multicast or unicast network

services. The data transport is augmented by a control protocol (RTCP) to allow monitoring

of the data delivery in a manner scalable to large multicast networks, and to provide minimal

control and identification functionality. RTP and RTCP are designed to be independent of the

underlying transport and network layers.

The header structure of RTP includes payload type,sequence number, timestamp and the synchronization source.

The RTP control protocol (RTCP) is based on the periodic transmission of control packets to all participants in the session, using the same distribution mechanism as the data packets. RTCP performs four functions:

The primary function is to provide feedback on the quality of the data distribution.This is an integral part of the RTP's role as a transport protocol and is related to the flow and congestion control functions of other transport protocols.

RTCP carries a persistent transport-level identifier for an RTP source called the canonical name or CNAME. Since the SSRC identifier may change if a conflict is discovered or a program is restarted, receivers require the CNAME to keep track of each participant. Receivers also require the CNAME to associate multiple data streams from a given participant in a set of related RTP sessions, for example to synchronize audio and video.

The first two functions require that all participants send RTCP packets, therefore the rate must be controlled in order for RTP to scale up to a large number of participants.

A fourth, optional function is to convey minimal session control information, for example participant identification to be displayed in the user interface.the primary function is to provide feedback on the quality of the data distribution.




4 Radio Channels






UTRAN SGSN GGSN PDN“Internet”

UMTS Bearer Service External BearerService

UMTS Bearer Service

Radio Access Bearer Service(RAB)

CN BearerService

BackboneBearer Service

Iu BearerService

Radio BearerService

Uu Iu

Teleservice

UE

Logical Channel

Transport Channel

Physical Channel

4 Radio Channels

4.1 Global Situation

A Radio Bearer is the service provided by a protocol entity (i.e. RLC protocol) for transfer of data between UE and UTRAN.

Radio bearers are the highest level of bearer services exchanged between UTRAN and UE.

Radio bearers are mapped successively on logical channels, transport channels and physical channels (Radio Physical Bearer Service on the figure)





“The RAB provides confidential transport of signaling and user data between UE and CN with the appropriate QoS”.

UTRAN

UE UMTS Bearer

UMTS Bearers

RABs (mapped on Radio & Iu Bearers)

CN-CS

CN-PS

Radio Bearers Iu Bearers

RAB

RAB

RABRAB

UMTS Bearer

UMTS bearer services

4 Radio Channels

4.2 RAB Presentation

AMR 12.2/12.2, 64/64Conversational (CS)

R2: 64/128, 64/384 64/144, 128/384, 144/384, 32/32, 64/64, 128/128, 144/144Background (PS)

14.4/14.4Streaming (CS)

Example of available RAB in R4

R2: 64/128, 64/384 64/144, 128/384, 144/384, 32/32, 64/64, 128/128, 144/144Interactive (PS)





4 Radio Channels

4.3 Radio Channels, Protocols & Network Elements

RRC

RLC

MAC

BMCPDCP


NAS Signaling

RRC Sig.

Voice Web Browsing

SMS Cell Broadcast

Radio Bearers

Traffic Logical Ch.

…Transport Channels

Uu Interface

RNC Node B UE

Physical Channels

MAC

…

Transport Channels

Control Logical Ch.

Control Plane

User Plane

The radio protocols are responsible for exchanges of signalling and user data between the UE and the UTRAN over the Uu interface:

User plane protocolsThese are the protocols implementing the actual Radio Access Bearer (RAB) service, i.e. carrying user data

through the access stratum.

Control plane protocolsThese are the protocols for controlling the radio access bearers and the connection between the UE and the

network from different aspects including requesting the service, controlling different transmission resources, handover & streamlining etc...

Also a mechanism for transparent transfer of Non Access Stratum (NAS) messages is included.

Some principles:The Radio Protocols are independent of the applied transport layer technology (ATM in R99): that may be

changed in the future while the Radio Protocols remain intact.

The main part of radio protocols are located in the RNC (and in the UE).

The Node-B is mainly a relay between UE and RNC.





Signaling Radio Bearers (SRB)

SRBs can carry:- layer 3 signaling (e.g. RRC connection establishment)- NAS signaling (e.g location update)

There can be up to 4 SRBs per RRC connection (one UE has one RRCconnection when connected to the UTRAN).

User Plane Radio Bearers

RABs are mapped on user plane RBs.

One RAB can be divided on RAB sub-flows and each sub-flow is mapped on one user plane RB.

e.g the AMR codec encodes/decodes speech into/from three sub-flows; each sub-flow can have its own channel coding.

4 Radio Channels

4.4 Radio Bearers

Please note that RAB (Radio Access Bearer) are only provided in the user plane.

What is a RRC connection?

When the UE needs to exchange any information with the network, it must first establish a signalling link with the UTRAN: it is made through a procedure with the RRC protocol and it is called “RRC connection establishment”.

During this procedure the UE will send an initial access request on CCCH to establish a signalling link which will be carried on a DCCH.

A given UE can have either zero or one RRC connection.





4 Radio Channels

4.5 Channel Types

Physical Channel

Transport Channel

Transport Channel

Transport Channel

Logical Channel

Logical Channel

Logical Channel

Packet Data

Speech

Signaling

TransmissionPhysicalResource

InformationType

QoSRequirements

In UMTS, 3 different types of channel are used:

Logical channelsEach logical channel is defined by what type of information is transferred. There are two main categories of Logical Channels: Traffic channels and Control channels.

Transport channelsEach transport channel is defined by how and with what characteristics data is transmitted over the radio interface. Transport channels are further subdivided into three categories: Dedicated channels, Common channels and Shared channels.

Physical channelsEach physical channel is defined by the physical radio resource used to convey information over he air. Physical channels are defined by a specific carrier frequency, scrambling code, channelization code (only when spreading is used), time start & stop (giving a duration) and, on the uplink, relative phase (0 or /2).





4 Radio Channels

4.6 Channels Vs. Interfaces

Uu Iub

Logical

Channels

Iub Frame Protocol

Transport Channel

Transport Channel

Physical Channel

Over the Iub interface (and Iur interface when in function), all the radio traffic is transmitted using specific Frame Protocols.

There is one Frame Protocol type per Transport Channel type.

On either side of iub interface Frame Protocols entities add header information to form Frame Protocols PDUs that are transported on the Iub interface over a transport bearer.





4 Radio Channels

4.7 Uu Protocol Layers

Layer 1Physical

Layer 3Network

Layer 2Data link

Control Plane User Plane

PHY (PHYsical)

MAC (Medium Access Control)

RLC (Radio Link Control)

PDCP BMC

RRC (Radio Resource Control)

Management functions: MM, CC

Non AccessStratum

AccessStratum

Network layer protocol:Ipv4, Ipv6, ... AMR

The radio interface (Uu) is divided into three protocol layers:Physical layer (L1)

Layer 1 supports all the functions required for transmission of bit streams on the physical medium. It is also in charge of measurement function which consists in indicating to higher layers, for example, FER (Frame Error Rate), SIR (Signal to Interference Ratio), interference power, transmit power, … It is composed of a “layer 1 management” entity, a “transport channel” entity, and a “physical channel” entity.

Data link layer (L2)

The layer 2 is responsible for providing functions such as mapping, ciphering, retransmission, segmentation.

Network layer (L3)

Layer 3 is split into 2 parts:

AS (Access Stratum)

AS is composed of the RRC (Radio Resource Control) entity.

NAS (Non Access Stratum)

NAS is composed of the CC (Call Control) and MM (Mobility Management) parts.

Protocol layers are located in the UE and peer entities are in the nodeB or the RNC.





4 Radio Channels

4.8 Physical Layer Architecture

Layer 1 Management

Transport sublayer

Physical sublayer

RLC/MAC

Layer 1 Layer 1 Management

Transport sublayer

Physical sublayer

RLC/MAC

NodeB

Radio interface (Uu)

Layer 2

UE

RNCTransport channels Transport channels

The layer 1 is used to transmit information under the form of electrical signals corresponding to bits, between the network and the mobile user. This information can be voice, circuit or packet data, and network signaling.

The UMTS layer 1 offers data transport services to higher layers. The access to these services is through the use of transport channels via the MAC sublayer.

These services are provided by radio links which are established by signaling procedures. These links are managed by the layer 1 management entity. One radio link is made of one or several transport channels, and one physical channel.

The UMTS layer 1 is divided into two sublayers: the transport and the physical sublayers. All the processing (channel coding, interleaving, etc.) is done by the transport sublayer in order to provide different services and their associated QoS. The physical sublayer is responsible for the modulation, which corresponds to the association of bits (coming from the transport sublayer) to electrical signals that can be carried over the air interface. The spreading operation is also done by the physical sublayer. These sublayers are well described in chapters 6 and 7.

These two parts of layer 1 are controlled by the layer 1 management (L1M) entity. It is made of several units located in each equipment, which exchange information through the use of control channels.





4 Radio Channels

4.9 Radio Interface Distributed Architecture

Iub

PHY

L1

ATM

AAL2

Frame Protocol

L1

ATM

AAL2

Frame Protocol

PHY

MAC

RLC

MAC

RLC

RRC RRC

UE NodeB RNC

Uu

In UMTS the radio protocol stack is split over several physical UTRAN nodes, namely the NodeB and the Serving RNC.

The NodeB hosts all the PHYsical layer components and is responsible for the entire Layer 1 processing.

The RNC hosts all the remaining protocol layers MAC, RLC and RRC and is in charge of the Layer 2 and Layer 3 functions.

Between Serving RNC and NodeB all the Radio traffic is carried on Iub with the help of specific Iub Frame Protocols.





Control Channels (CCH)Broadcast Control Channel (BCCH)

Traffic Channels (TCH)

Paging Control Channel (PCCH)

MBMS Control Channel (MCCH)

Common Control Channel (CCCH)

Common Traffic Channel (CTCH)

UTRAN UELogical Channels

4 Radio Channels

4.10 Logical Channels

MBMS Scheduling Channel (MSCH)

Dedicated Traffic Channel (DTCH)

MBMS Traffic Channel (MTCH)

Dedicated Control Channel (DCCH)

The logical channels are divided into:

Control channels for the transfer of control plane information

Traffic channels for the transfer of user plane information





4 Radio Channels

4.10 Logical Channels [cont.]

UL or DL What type of information?

BCCH System control informatione.g cell identity, uplink interference level

PCCH Paging informatione.g CN originated call when the network does not know the location cell of the UE

CCCH Control informatione.g initial access (RRC connection request), cell update

DCCH Control information (but the UE must have an RRC connection)

MCCH Carries control plane information between network and UEs

MSCH Carries transmission schedule between network and UEs

DTCH Traffic information dedicated to one UE e.g speech, fax, web browsing

CTCH Traffic information to all or a group of UEs e.g SMS-Cell Broadcast

MTCH Carries user plane traffic





4 Radio Channels

4.11 Why Transport Channels?

A transport channel offers a flexible pattern to arrange information on any service-specific rate, delay or coding before mapping it on a physical channel:

• it provides flexibility in traffic variation

• it enables multiplexing of transport channels on the same physical channel

Transport channels provide an efficient and fast flexibility in radio resource management.

Time

Traffic

Time IntervalTransport Channel

The transport channels provides a flexible pattern to exchange data between UTRAN and the UE at a variable bit rate for the multimedia services.

The logical channels are mapped on the transport channels by the MAC protocols.

By this way the data are processed according to the QoS required before sending them to the Node B by the Iub.





4 Radio Channels

4.12 Structure of a Transport Channel

168

168

168

168

168

168

168 bits

20 ms

Time Transmission Interval (TTI): periodicity at which a Transport Block Set is transferred by the physical layer on the radio interface

20 ms

Transport Block: basic unit exchanged over transport channels.

Transport Format (TF): it may be changed every TTI. Each TF must belong to the Transport Format Set (TFS) of the transport channel

168

168

>> The system delivers one Transport Block Set to the >> The system delivers one Transport Block Set to the physical layer every TTIphysical layer every TTI: what is the delivery bit rate of the : what is the delivery bit rate of the transport blocks to the physical layer during the first TTI?transport blocks to the physical layer during the first TTI?

20 ms 20 ms

A transport channel is defined by a Transport Format (TF) which may change every Time Transmission Interval (TTI).

The TF is made of a Transport Block Set. The Transport Block size and the number of Transport Block inside the set are dynamical parameters.

The TTI is a static parameter and is set typically at 10, 20 or 40 ms.

For example,

For a video-call (CS service at 64 kbps)

TTI = 20 ms

TFS = (640* 0,2)

Turbo coding (coding rate=1/3)

16 CRC bits

For a PS 64 kbps service

TTI=20 ms

TFS = (336* 0,1,2,3,4)

Turbo coding (coding rate=1/3)

16 CRC bits





4 Radio Channels

4.12 Structure of a Transport Channel [cont.]

Transport Format (TF)

• Semi-static part (can be changed, but long process) Transmission Time Interval (TTI),Coding scheme...

• Dynamic part (may be changed easily) Size of transport block, Number of transport blocks per TTI

Transport Format Set (TFS)

It is the set of allowed Transport Formats for a transport channel, which is assigned by RRC protocol entity to MAC protocol entity.

MAC chooses TF among TFS.

MAC may choose another TF every TTI without interchanging with RRC protocol (fast radio resource control).

What is TTI (Transmission Time Interval)?

it is equal to the periodicity at which a Transport Block Set is transferred by the physical layer on the radio interface

it is always a multiple of the minimum interleaving period (e.g. 10ms, the length of one Radio Frame)

MAC delivers one Transport Block Set to the physical layer every TTI.

What does the TFS provide ?

The selection at each TTI of a number of transport block among the allowed list provides the required flexibility for the variable traffic and allows to manages the priority.





4 Radio Channels

4.13 Transport Channels: Example

576

576

576

576

576

576

576 bits

576

576

40 ms

3. How many Transport Format(s) may be chosen for this transport3. How many Transport Format(s) may be chosen for this transport channel?channel?

4. Can you imagine why the transfer has been interrupted during 4. Can you imagine why the transfer has been interrupted during the third TTI? the third TTI?

Static PartTTI ?Coding scheme Turbo coding, coding rate= 1/ 3CRC 16 bits

Dynamic PartTransport Block Size ?Transport Block Size Set 576*B (B= 0,1,2,3,4)

1. Complete the table1. Complete the table

2.2. What is the delivery What is the delivery bit rate of the transport bit rate of the transport blocks to the physical blocks to the physical layer during the first layer during the first TTI?TTI?





4 Radio Channels

4.14 Transport Channels

Common Channels

Broadcast Channel (BCH)

Dedicated Channels

Paging Channel (PCH)

Random Access Channel (RACH)

Forward Access Channel (FACH)

Dedicated Channel (DCH)

Common Packet Channel (CPCH)

Downlink Shared Channel (DSCH)

UTRAN Transport Channels UE

The transport channels are divided into:

Common channels: they are divided between all or a group of UEs in a cell. They require in-band identification of the UEs when addressing particular UEs.

Dedicated channels: it is reserved for a single UE only. In-band identification is not necessary, a given UE is identified by the physical channel (code and frequency in FDD mode)





4 Radio Channels

4.15 Common Transport Channels

BCH: Broadcast Channel

A downlink transport channel that is used to carry BCCH. The BCH is always transmitted with high power over the entire cell with a low fixed bit rate.

>> The BCH is the only transport channel with a single transport>> The BCH is the only transport channel with a single transport format (no format (no flexibility). Can you explain why?flexibility). Can you explain why?

PCH: Paging Channel

A downlink transport channel that is used to carry PCCH. It is always transmitted over the entire cell.

>> Is it possible to carry all types of information on the PCH?>> Is it possible to carry all types of information on the PCH?

BCH

high power to reach all the user and low fixed bit rate so that all terminals can decode the data rate whatever its ability: only one Transport Format because there is no need for flexibility (fixed bit rate)

PCH

only two transport channels can NOT carry user information: BCH and PCH.





4 Radio Channels

4.15 Common Transport Channels [cont.]

FACH: Forward Access Channel

A downlink transport channel that is used to carry control information. It may also carry short users packets. The FACH is transmitted over the entire cell or over only a part of the cell using beam-forming antennas. The FACH uses open loop power control (slow power control).

>> In which case is it interesting to use beam>> In which case is it interesting to use beam--forming antennas? would it also be forming antennas? would it also be relevant to implement this feature for PCH?relevant to implement this feature for PCH?

RACH: Random Access Channel

An uplink transport channel that is used to carry control information from the mobile especially at the initial access. It may also carry short user packets. The RACH is always received from the entire cell and is characterized by a limited size data field, a collision risk and by the use of open loop power control (slow power control).

>> Why is it interesting to carry short user packets on RACH in >> Why is it interesting to carry short user packets on RACH in spite of limited data spite of limited data field and collision risk (instead of using a dedicated channel)?field and collision risk (instead of using a dedicated channel)?

Note: Beam-forming is also called “Inherent addressing of users”: it is the possibility of transmission to a certain part of the cell.

RACH and FACH are mainly used to carry signalling (e.g at the initial access), but they can also carry small amounts of data.

When a UE sends information on the RACH, it will receive information on FACH.





4 Radio Channels

4.15 Common Transport Channels [cont.]

DSCH: Downlink Shared Channel

A downlink transport channel shared by several UEs to carry dedicated control or user information. When a UE is using the DSCH, it always has an associated DCH, which provides power control.

CPCH: Common Packet Channel

An uplink transport channel that is used to carry long user data packets and control packets. It is a contention based random access channel. It is always associated with a dedicated channel on the downlink, which provides power control.

Transfer of signalling and traffic on a shared basis

DSCH and CCPH seem to be symmetrical, but:

DSCH is on the DL, so that different user data are synchronised with each other (the information on whether the UE should receive the DSCH or not is conveyed on the associated DCH)

CPCH is on the UL, so that different user data can NOT be synchronised (the mobile phones are not synchronised). It may cause big problem of collisions!





4 Radio Channels

4.16 Dedicated Transport Channels

DCH: Dedicated Channel

A downlink or uplink transport channel that is used to carry user or control information. It is characterized by features such as fast rate change (on a frame-by-frame basis), fast power control, use of beam-forming and support of soft HO.

DCH

It is different from GSM where TCH carries user data (e.g speech frames) and ACCH carries higher layer signalling (e.g HO commands)

User data and signalling are therefore treated in the same way from the physical layer (although set of parameters may be different between data and signalling)

wide range of Transport Format Set permits to be very flexible concerning the bit rate, the interleaving...

Fast Power Control and soft HO are only applied on this transport channel.





Control Logical Channels

BCCH PCCH CCCH MSCH MCCH DCCH

Traffic Logical Channels

DTCH CTCH MTCH

BCH PCH RACH FACH DSCH CPCH DCH

Common Transport Channels Dedicated Transport Channels

4 Radio Channels

4.17 Mapping Logical / Transport Channels





4 Radio Channels

4.17 Mapping Logical / Transport Channels [cont.]

Control Logical Channels

BCCH PCCH CCCH DCCH

Traffic Logical Channels

DTCH CTCH

BCH PCH RACH FACH DSCH CPCH DCH

Common Transport Channels Dedicated Transport Channels

According to the slide above and the previous one, we can say state that :

Except BCH and PCH, each type of transport channel can be used for the transfer of either control or traffic logical channels.





4 Radio Channels

4.18 Physical Channels

RNC

Node B

IubTransport Channels

For the UE point of view, the network is just the physical channels.

There are several kinds of physical channels.

• Channel associated with transport channel

• UTRAN Signaling (mobility management)

• Core Network Signaling (authentication)

• User Traffic (voice)

There are common and dedicated channels

• Channels not associated with transport channel, the physical signaling.

• Cell Search Selection

• System Information Collection

• Connection Request and Paging Surveillance

These channels and resources allowing the UE to share these channels with other users are the radio resources

We will see later how data from transport channel are processed to be mapped on the physical channels and how a UE uses these channels.

On a cell, all the physical channels are sent on the same frequency and on the same time.

It is due to the radio technology, the WCDMA, really different than the one used with the GSM.

Here the physical channels are separated by codes. We will see this point on the next chapter.





4 Radio Channels

4.19 Physical Channel List

Not associated with transport channels

• CPICH: Common Pilot Channel

• PICH: Page Indicator Channel

• MICH: MBMS Indication Channel

• P-SCH & S-SCH: Primary & Secondary Synchronization Channel

• AICH: Acquisition Indicator Channel

Common Physical Channels, associated with transport channels

• P-CCPCH & S-CCPCH: Primary & Secondary Common Control Channel

• PRACH: Physical Random Access Channel

• PDSCH: Physical Downlink Shared Channel

• PCPCH: Physical Common Packet Channel

Dedicated Physical Channels, associated with transport channels

• DPDCH: Dedicated Physical Data Channel

• DPCCH: Dedicated Physical Control Channel





4 Radio Channels

4.20 Downlink

Logical Ch

Transport Ch

Physical Ch

AICHNot associated with transport channels PICH CPICH P-SCH S-SCH

PDSCH S-CCPCH P-CCPCHDPDCH

+ DPCCH

DTCH, DCCH CCCH, CTCH

BCHPCHFACHDSCH

Not implemented yet in Alactel-Lucent Solution

PCCH BCCH

DPDCH and DPCCH multiplexed by time

Common Physical ChDedicated Physical Ch

MICH

MSCH, MCCHMTCH

MSCH, MCCH, MTCH map to FACH (only in DL)

DCH1 DCH2

CCTrCH

Some common transport channels are multiplexed on the same physical channels. Like the FACH and the PCH on the S-CCPCH.

The FACH is a downlink common channel to carry the traffic and the control data.

The PCH is the Paging channel.

By the same principles, several DCH (Dedicated channel) belonging to the same user are mapped on one physical channel, the DPDCH. The DPCCH is its control channel at the physical level.





4 Radio Channels

4.21 Uplink

Logical Ch

Transport Ch

Physical Ch

PRACH PCPCHDPDCH +

DPCCH

DTCH, DCCH CCCH

DCH1 RACHDCH2

CCTrCH

CPCH

DPDCH and DPCCH multiplexed by modulation

Dedicated Physical Ch Common Physical Ch

There are less channels in uplink. For the physical channels, there are the dedicated channels (DPDCH) and the common channels (PRACH).

The PCPCH is not implemented in the Alactel-Lucent Solution.





A physical channel is defined by:

•A carrier• Some codes (see 4.3 and 4.4 part)• A start and stop instant

Physical channels are sent continuously on the air interface between start and stop instants.

4 Radio Channels

4.22 Physical Channels: Structure

15 Time Slots

Radio Frame = 10 ms

N bits (according to the bit rate)

….

1 Time slot = 0.666 ms

After channel coding each transport block is split into radio frames of 10 ms.

The bit rate may be changed for each frame.

Each radio frame is also split into 15 time slots.

But all time slots belong to the same user (this slot structure has nothing to do with the TDMA structure in GSM).

All time slots of a same TDMA frame have the same bit rate.

Fast power control may be performed for each time slot (1500 Hz).

The number of chips for one bit M is equivalent to the spreading factor. It can easily be computed with knowledge of N:

In fact the spreading factor must be equal to 4, 8, 16…256.

Consequently it may be necessary to add some padding bits to match the adequate value of spreading factor (rate matching).




5 UTRAN Radio Protocols







5.1 Radio protocol stack

Layer 3

Control plane User plane

Layer 2/MAC

Layer 1

Transport Channels

Bearers (called RAB in user plane)Access Stratum

SAP

Non Access Stratum

cont

rol

cont

rol co

ntro

l

PHY

MAC

RRC

Logical Channels

Layer 2/RLC

Radio Bearers

RLC RLCRLC

RLCRLC

RLCRLCRLC

PDCPPDCP

BMCcon

tro

l

control

Layer 2/PDCPLayer 2/BMC

Physical Channels

The radio protocols are responsible for exchanges of signalling and user data between the UE and the UTRAN over the Uu interface

The radio protocols are layered into:

the RRC protocol located in RNC* and UE

the RLC protocol located in RNC* and UE

the MAC protocol located in RNC* and UE

the physical layer (on the air interface) located in Node-B and UE

Two additional service-dependent protocols exists in the user plane in the layer 2: PDCP and BMC.

Each layer provides services to upper layers at Service Access Points (SAP) on a peer-to-peer communication basis. The SAP are marked with circles. A service is defined by a set of service primitives.

Radio Interface Protocol Architecture is described in 3GPP 25.301.

(*except a part of protocol used for BCH which is terminated in Node-B)






5.2 Radio Resource Control (RRC)

cont

rol

cont

rol

cont

rol

PHY

MAC

RRC

RLC

BearersCall management

Radio mobility management

Measurement control and reporting

Outer loop power controlRadio Bearers(control plane)

RRC is the brain of the radio interface protocol stack.

Layer 3

cont

rol

cont

rol

PDCP

BMC

RRC is a protocol which belongs to control plane.

The RRC functions are:

Call management

RRC connection establishment/release (initial access)

Radio Bearer establishment/release/reconfiguration (in the control plane and in the user plane)

Transport and Physical Channels reconfiguration

Radio mobility management

Handover (soft and hard)

Cell and URA update (see “5.UTRAN/ Mobility Management”)

Paging procedure

Measurements control (UTRAN side) and reporting (UE side)

Outer Loop Power Control

Control of radio channel ciphering and deciphering

RRC can control locally the configuration of the lower layers (RLC, MAC...) through Control SAP. These Control services are not requiring peer-to-peer communication, one or more sub-layers can be bypassed.

See 3GPP 25.331 RRC protocol (over 500 pages!)






5.3 PDCP and BMC Protocols

PDCP (Packet Data Convergence Protocol)

- in the user plane, only for services from the PS domain

- it contains compression methods

In R99 only a header compression method is mentioned (RFC2507).

Why is header compression valuable?

e.g a combined RTP/UDP/IP headers is at least 60 bytes for IPv6, when IP voice service header can be about 20 bytes or less.

BMC (Broadcast/Multicast Services)

- in the user plane

- to adapt broadcast and multicast services from NAS on the radio interface

In R99 the only service using this protocol is SMS Cell Broadcast Service (directly taken from GSM).

See 3 GPP 25.323 (PDCP protocol) and 25.324 (BMC protocol)






5.4 Radio Link Control (RLC)

TrafficLogical

Channels

Radio Bearers(user plane)

Radio Bearers(control plane)

RLC RLCRLC

RLCRLC

RLCRLCRLC

ControlLogical

Channels

Segmentation

Buffering

Data transfer with 3 configuration modes:

- Transparent (TM)

- Unacknowledged (UM)

- Acknowledged (AM)

Ciphering

RLC provides segmentation and (in AM mode) reliable data transfer.

Layer 2/upper part

There is no difference between RLC instances in Control and User planes. There is a single RLC connection per Radio Bearer.

RLC main functions:

RLC Connection Establishment/Release in 3 configuration modes:

- transparent data transfer (TM): without adding any protocol information

- unacknowledged data transfer (UM): without guaranteeing delivery to the peer entity (but can detect transmission errors)

acknowledged data transfer (AM): with guaranteeing delivery to the peer entity. The AM mode provides reliable link (error detection and recovery, in-sequence delivery, duplicate detection, flow Control, ARQ mechanisms)

ARQ=Automatic Repeat Request (it manages retransmissions)

Transmission/Reception buffer

Segmentation and reassembly (to adjust the radio bearer size to the actual set of transport formats)

Mapping between Radio Bearers and Logical Channels (one to one)

Ciphering for non-transparent RLC data (if not performed in MAC), using the UEA1, Kasumi algorithm specified in R’99

Encryption is performed in accordance with TS 33.102 (radio interface), 25.413, 25.331(RRC signaling messages) and supports the settings of integrity with CN (CS-domain/PS-domain)

3GPP 25.322 RLC protocol






5.5 Medium Access Control (MAC)

Transport Channels

(common and dedicated)

Basic data transfer

Multiplexing of logical channels

Priority handling/Scheduling (TFC selection)

Reporting of measurements

Ciphering

MAC can switch a common channel into a dedicated channel if higher bit rate is required (on request of L3-level).

MAC can change dynamically Transport Format (bit rate…) of each transport channel on a frame basis (each 10 ms) without interchanging with L3-level.

MAC provides flexible data transfer.

TrafficLogical

Channels

ControlLogical

Channels

MACLayer 2/

lower part

MAC belongs to control plane and to user plane.

MAC main functions:

Data transfer: MAC provides unacknowledged data transfer without segmentation

Multiplexing of logical channels (possible only if they require the same QoS)

Mapping between Logical Channels and Transport Channels

Selection of appropriate Transport Format for each Transport Channel depending on instantaneous source rate.

Priority handling/Scheduling according to priorities given by upper layers:

- between data flows of one UE

- between different UEs

Priority handling/Scheduling is done through Transport Format Combination (TFC) selection

Reporting of monitoring to RRC

Ciphering for RLC transparent data (if not performed in RLC)

3GPP 25.321 MAC protocol






5.6 The Physical Layer

DedicatedPhysical Channels

Multiplexing of transport ch.

Spreading/modulation

RF processing

Power control

Measurements

Physical layer

DedicatedTransport Channels

The physical layer provides multiplexing and radio frequency processing with a CDMA method.

Air Interface

CommonTransport Channels

CommonPhysical Channels

Layer 1

The physical layer belongs to control plane and to user plane.

Physical layer main functions:

Multiplexing/de-multiplexing of transport channels on CCTrCH (Coded Composite Transport Channel) even if the transport channels require different QoS.

Mapping of CCTrCH on physical channels

Spreading/de-spreading and modulation/demodulation of physical channels

RF processing (3 GPP 25.10x)

Frequency and time (chip, bit, slot, frame) synchronization

Measurements and indication to higher layers (e.g. FER, SIR, interference power, transmit power, etc.)

Open loop and Inner loop power control

Macro-diversity distribution/combining and soft handover execution

3GPP 25.2xx




6 Radio Resource control Layer







6.1 RRC Main Functions

• RRC connection management

• Radio Bearers management

• Radio resources management

• Paging / Notification

• System information broadcast

• Measurement reporting management

• Outer loop power control management

• Ciphering management

• Integrity processing

• Routing of higher layer PDUs

RNCUE

RRC Connection

Many functions are managed by the RRC layer. Here is the list of the most important: Establishment, re-establishment, maintenance and release of an RRC connection between

the UE and UTRAN: it includes an optional cell re-selection, an admission control, and a layer 2 signaling link establishment. When a RNC is in charge of a specific connection towards a UE, it acts as the Serving RNC.

Establishment, reconfiguration and release of Radio Bearers: a number of Radio Bearers can be established for a UE at the same time. These bearers are configured depending on the requested QoS. The RNC is also in charge of ensuring that the requested QoS can be met.

Assignment, reconfiguration and release of radio resources for the RRC connection: it handles the assignment of radio resources (e.g. codes, shared channels). RRC communicates with the UE to indicate new resources allocation when handovers are managed.

Paging/Notification: it broadcasts paging information from network to UEs. Broadcasting of information provided by the Non-Access Stratum (Core Network) or Access

Stratum. This corresponds to “system information” regularly repeated. UE measurement reporting and control of the reporting: RRC indicates what to measure,

when and how to report. Outer loop power control: controls setting of the target values. Control of ciphering: provides procedures for setting of ciphering.

The RRC layer is defined in the 25.331 3GPP specification.






6.2 RRC States

Camping on a UTRAN cell

Idle Mode

Cell_DCH Cell_FACH

Cell_PCHURA_PCH

UTRA RRC CONNECTED MODE

The above figure shows the RRC states in UTRA RRC Connected Mode, including transitions between UTRA RRC connected mode and GSM connected mode for CS domain services, and between UTRA RRC connected mode and GSM/GPRS packet modes for PS domain services. It also shows the transitions between Idle Mode and UTRA RRC Connected Mode and furthermore the transitions within UTRA RRC connected mode.

The RRC connection is defined as a point-to-point bi-directional connection between RRC peer entities in the UE and the UTRAN characterized by the allocation of a U-RNTI.

A UE has either zero or one RRC connection.

After power on, UE stays in Idle mode until it transmits a request to establish an RRC connection. The Connected mode is entered when the RRC connection is established between UE and Serving RNC. UE leaves the Connected mode and returns to Idle mode when the RRC connection is released or at RRC connection failure.

Two modes of operation are defined for the UE: Idle mode and UTRA RRC Connected mode.

The four RRC states in UTRA RRC Connected Mode are: URA_PCH, CELL_PCH, CELL_DCH, CELL_FACH.




7 Exercises






MSCH MCCH

7 Exercises

7.1 MAC protocol

CCCHPCCHBCCH CTCH DTCHDCCH DTCHBCCH

FACH RACH DSCH

Iur or local

DCH DCH

MAC-d

MAC-c/sh/m

CPCHFACHPCH

MAC Control

DSCH

MAC-b

BCH

MTCHMTCH

Look at this figure and answer the questions on the following paLook at this figure and answer the questions on the following pages.ges.





7 Exercises

7.1 MAC protocol [cont.]

1. On which logical/transport channels will be mapped: system information broadcasting paging telephony speech internet browsing at a high bit rate internet browsing at a low bit rate

Can you imagine a situation where the UE will use 2 DTCHs (or more) at the same time?

2. Guess the meaning of “MAC-b” “MAC-c/sh”, MAC-m and “MAC-d”.

3. Why is there one MAC-d entity on the UE side and several MAC-d entities on the UTRAN side?

4. What is the link between MAC-c/sh and MAC-d for?





7 Exercises

7.1 MAC protocol [cont.]

5. What are the 4 main functions of MAC protocol?

6. MAC can multiplex logical channels only if they require the same QoS: true or false?

7. Which entity is responsible for TFS selection? TF allocation?

8. Will the physical channel configuration be changed(e.g modification of spreading factor) when MAC selects a new TFinside TFS?

9. MAC makes measurement reports to RRC: why is it necessary?





End of moduleUTRAN System Description





Module 2WCDMA for UMTS







UTRAN · UA08 9300 W-CDMA R99 Radio PrinciplesW-CDMA R99 Radio Principles · WCDMA for UMTS1 · 2 · 2


Blank page


Document History







Module objectives


Define a Radio Resource in 3G











Table of contents


1 Context 71.1 Historical 81.2 Advantages & Disadvantages 91.3 3GPP 102 Analogy 112.1 WCDMA and Restaurant 123 Spread Spectrum Modulation 153.1 A Code as a Shell against Noise 163.2 Spectrum spreading 173.3 Transmission Chain 183.4 Code & Spreading factor 193.5 Spreading factor & Data Rate 203.6 Spreading factor & Error at reception 213.7 Exercise: Orthogonal Code 233.7 WCDMA, Power Density & Processing Gain 244 Code Division Multiple Access 264.1 One-cell reuse 274.2 Multiple access 284.3 Spreading: Channelization and Scrambling 304.4 Channelization Codes (Spreading Codes) 314.5 Scrambling codes 325 Soft Handover 335.1 Introduction 345.2 Scenarios: Softer Handover 355.3 Scenarios: Soft Handover intra RNC 365.4 Scenarios: Soft Handover inter RNC 375.5 Scenarios: SRNC Relocation 385.6 Soft Handover & Code Management 395.7 Cost & Benefit 406 Rake Receiver 426.1 Rake Receiver principle 436.2 Rake Receiver and Multi-Service 456.3 Rake Receiver and soft handover 466.4 Rake Receiver and Path Diversity 477 Power Control 497.1 Why ? 507.2 Different kinds of Power Control 517.3 Open Loop Power Control 527.4 Closed Loop Power Control: Principle 537.4 Closed Loop Power Control: Power Density 547.5 UL Closed Loop PC, in case of Soft Handover 557.5 DL Closed Loop PC, in case of Soft Handover 568 Capacity, Coverage & Quality 578.1 Links between Coverage, Capacity and Quality 588.2 Improvement Ways 598.3 Typical Values 60






Switch to notes view! Page




1 Context






1 Context

1.1 Historical

Early 70’sCDMA developed for military field for its great qualities of privacy (low probability interception, interference rejection)

1996CDMA commercial launch in the USThis system called IS-95 or cdmaOne was developed by Qualcomm and has reached 50 million subscribers worldwide

2000IMT-2000 has selected three CDMA radio interfaces:- WCDMA (UTRA FDD)- TD-CDMA (UTRA TDD)- CDMA 2000

In the following material we will only refer to WCDMA (UTRA FDD)

See http://www.cdg.org for IS-95

In CDMA field, we have experience of IS-95

IS-95 vocabulary:

forward channel=downlink

reverse channel=uplink

handoff=handover





1 Context

1.2 Advantages & Disadvantages

CDMA is very attractive:

• Better spectrum efficiency than 2G systems

• Suitable for all type of services (circuit, packet) and for multi-services

• Enhanced privacy

• Evolutionary (linked with progress in signal processing field)

BUT:

• Complex system: not easy to configure and to manage

• Unstable in case of congestion

Spectrum efficiency : transmission capacity per spectrum unit (bandwidth), i.e kbit/MHz.

This must not be confused with the traffic capacity.

The spectrum efficiency in UMTS is higher than in GSM (25x200kHz carriers in GSM offering 335 kbps** while a 5 MHz UMTS carrier offers 400 kbps).

If we factor in densification (frequency reuse pattern), the UMTS traffic capacity is dramatically increased. According to CDMA Development Group:

“Capacity increases by a factor of between 8 to 10 compared to an AMPS

analog system and between 4 to 5 times compared to a GSM system”





1 Context

1.3 3GPP

The 3GPP is the organization in charge of the standardization of the UMTS.It is made of standardization organization (ETSI in Europe, T1 in USA, ARIB in Japan or CTWS in China …), member of manufacturers and operators. The UMTS frequency allocations are :

TDD FDD MSS TDD1900 1980 2010 20251920

MSSFDD2110 2170 2200

FDD: Frequency Division DuplexTDD: Time Division DuplexMSS: Mobile Satellite System

Uplink Downlink




2 Analogy






• Cell

Restaurant room

2 Analogy

2.1 WCDMA and Restaurant

WCDMA Restaurant Room

• UE

People at table

• Code

Language

Enjoy your meal !

Code 1

Code 2

Guten appetite !

Bon appetit !

Bom apetite !

Ues, like people, send and receive on the same time and the same frequency. They are separeted by:

For a table, the conversations of the neighbours are noise, for a UE it is the same principle: neighbour conversations are interference

The equivalence are:

Restaurant room -> Cell

Table -> UE

Language -> Code

Here the important point is all the UEs send and receive on the same time and on the same frequency. The WCDMA is really different because with the GSM, the UEs are separated by the time (TS of TDMA) and the frequency. Here the UEs are separated with codes applied on the signals.

Another important point is for someone the conversation on a neighbour table is considered like noise. It is the same principle with the WCDMA, for a user the other UEs generates some noises.





2 Analogy

2.1 WCDMA and Restaurant [cont.]


•Node B

Steward

Downlink

Who have order this

cake ?

????

???Impacts:

•Power Control in DL

•Control Admission

Very important !

Interference level in DL

problem:

•If some UE use too much power

•If there are too many users in the cell

Enjoy your meal !

COMO ESTAS ?

In downlink,

In the restaurant, the steward want to ask to every table who have order a cake. If some people speak to loud, the table at the back of the room can’t hear the question. It is the same case, if there are too many users in the room.

In the cell, it is the same principle. If there are too many Ues on the cell or if some Ues use too much power, the interference level for a UE far from the Node B is too high to allow the UE decoding the message.





2 Analogy

2.1 WCDMA and Restaurant [cont.]


It is for me !

Who have order this

cake ?

QUIERO LA

TARTA!!

Es ist meine

Uplink

C’est à la pomme ?

????

At the Node B level:

• If a UE, close to the NB, speak too loud

•If there are too many users

Problem of interference level too high.

The NB can’t decode any users anymore.

Impacts:

• Power Control in UL

•Admission Control

Very important

In Uplink,

In the restaurant, a steward can understand all the conversation if he knows all the languages.

But if on a table, close to him, some one speak to loud the steward can’t understand people on the other tables. It is the same problem if there are too many people it is too noisy to able to understand a conversation far from him.

With the WCDMA, there is the same problem. That means if the cell is too load,

the interference level at the Node B is too high to be able to decode the weakest signal.




3 Spread Spectrum Modulation







3.1 A Code as a Shell against Noise

The letter ‘A’ represents the signal to transmit over the radio interface.

At the transmitter the height (ie the power) of ‘A’ is spread, while a color (i.e a code) is added to ‘A’ to identify the message .

At the receiver ‘A’ can be retrieved with knowledge of the code, even if the power of the received signal is below the power of noise due to the radio channel.

ReceiverTransmitter

Spreading

Noise

DespreadingRadio Channel






3.2 Spectrum spreading

At the transmitter the signal is multiplied by a code which spreads the signal over a wide bandwidth while decreasing the power (per unit of spectrum).At the receiver it is possible to retrieve the wanted signal by multiplying the received signal by the same code: you get a peak of correlation, while the noise level due to the radio channel remains the same, because this is not correlated with the code.But the interference level is too high, it is not possible to decode any message.

???

f

P

Spreading

Radio channel

Despreading

Interference Level

f

P

f

P

f

P

What is the interference level ?

The interference level is the power received on the UMTS bandwidth used. These interferences are made of:

the background noise,

the messages of the other users,

the traffic on the neighbouring cells.

Because all the users on a cells use the same bandwidth on the same time, and the users on the other cells too, the decoding and so the error ratio depend on the interference level.






3.3 Transmission Chain

Air Interface

The narrowband data signal is multiplied bit per bit by a code sequence: it is known as “chipping”.

The chip rate (fixed) of this code sequence is much higher than the bit rate of the data signal: it produces a wideband signal, also called spread signal.

At the receiver the same code sequence in phase should be used to retrieve the original data signal.

Modulator Demodulator

Code Sequence

Data Data

Code sequence

NB-Signal WB-Signal NB-SignalWB-Signal

Code synchronization between the transmitter and the receiver is crucial for de-spreading the wideband signal successfully.






3.4 Code & Spreading factor

The code is applied on each bit of the user data.

The Spreading Factor, called SF, is the length of this code.

Example: Data to transmit: 1 0 , SF=8.

1-1

1-1

Spread data

Code

Coded data

Transmission

Reception

Received data, without error

1-1

A chip

Chip rate fixed at 3.84 Mchip/s

Code applied

1-1

1-1

1-1

What is the spreading factor?

It is the number of chips per bit (=chip rate/bit rate).

The chip rate is linked with the CDMA carrier bandwidth and has a constant value of 3,84 Mcps.

It is quite easy to match the bit rate of the signal with the CDMA chip rate just by choosing the adequate spreading factor.

The higher the spreading factor, the more redundancy you add in the signal and the lower the probability of bit error is by transmitting the signal.

It is also traduced by the processing gain (see below).

Code synchronization?

It is difficult to acquire and to maintain the synchronization of the locally generated code signal and the received signal.

Indeed synchronization has to be kept within a fraction of the chip time.






3.5 Spreading factor & Data Rate

The chip rate is fixed, 3.84 Mchip/s.

If the SF is divided by 2, the data rate is multiplied by 2 !


Spread data

Code

Coded data

Transmission

Reception

Received data, without error

Code applied

Received data

Small SF = High data rate High SF = Small data rate

1-1

1-1

1-1

1-1

1-1

1-1

The Spreading Factor available are 4, 8, 16, 32, 64, 128, 256 in uplink, plus 512 in downlink for signaling at very low bit rate.






3.6 Spreading factor & Error at reception

When an error occurs at the reception, the determination of the bit value is less trivial.


Zoom on the decoded

signal

1

-1

0

The determination of the bit value is based on the area of the received signal.

Here is 6 area units over 8

1-1

1-1

Signal sent on the air Signal received with error

Code

SF=8

Decoded data






3.6 Spreading factor & Error at reception [cont.]

1-1

1-1

Signal sent on the air Signal received with error

Code

SF=4

Zoom on the

decoded signal

Decoded data

1

-1

0

The determination of the bit value is based on the area of the received signal.

Here is 2 area units over 4

With a small SF, the signal is more sensitive to errors. So to have the same error ratio you use more power

If you need a high data rate (video downloading), you will use a small SF. You will have more errors on your message. So if you want to keep the same error ratio, you will use more power to transmit your message

To keep in mind

Another way to understand this relation is with the redundancy.

If the SF is small, 4 for example, the useful bit, 0 or 1, is sent just 4 time. The data rate is high.

If the SF is higher, 64 for example, the useful bit is sent 64 time. The data rate is smaller.

So if an error occurs, it is more significant if the SF is 4 than if the SF is 64.






3.7 Exercise: Orthogonal Code

Here, there is a received signal and two orthogonal codes

Could you apply these codes on the received signal and determinate which code has been used to spread the signal? What could you conclude about the orthogonality?

Received signal

Code 1

Decoded signal 1

Code 1Code 2

Code 2

1-1

1-1

1-1

1-1

1-1

1-1

Received signal

Decoded signal 2






3.7 WCDMA, Power Density & Processing Gain

•RSSI: Received Signal Strength Indicator

Total received wideband power over 5 MHz including thermal noise

•ISCP (No): Interference Signal Code PowerInterference on the received signal

•RSCP (Ec): Received Signal Code Power

Unbiaised measurement on the received signal on one channelization code

• Eb : energy per useful bit

• PG : Processing Gain = Eb-Ec (in dB)

Power Gain after despreading. PG= 10 log (SF) f

P

RSSI or Io

ISCP or No

SIR

PG

Eb

RSCP or Ec

At Node B reception levelWssWs

RSSI: This is the total received wideband (UTRA carrier RSSI) power over 5Mhz

including thermal noise. It is estimating the uplink interference at the Node B, and by difference with the thermal noise, the rise due to traffic and external interference.





Depending on the service, more or less errors are allowed. UTRAN computes the error ratio and then set the SIR required for the service.

What are the modifications on the diagram if:

•The number of users increases ?

•The SF decreases ?

SIR: Signal Interference Ratio

No

RSCPSFSIR

.


3.7 WCDMA, Power Density & Processing Gain [cont.]

f

P

RSSI or Io

ISCP or No

SIR

PG

Eb

RSCP or Ec

At Node B reception levelWssWs




4 Code Division Multiple Access







4.1 One-cell reuse

The area is divided into cells, but the entire bandwidth is reused in each cell (frequency reuse of one)

> Inter-cell interference

> Cell orthogonality is achieved by codes

The entire bandwidth is used by each user at the same time

> Intra-cell interference

> User orthogonality is achieved by codes

The rainbows cells mean that the whole bandwidth (5 MHz) is reused in each cell.

In GSM there is also intra-cell interference when there are 2 (or more) TRXs in the same cell. But it is a small problem (as each TRX runs on a different frequency)

In CDMA intra-cell interference is an important problem.






4.2 Multiple access

All the users transmit on the same 5 MHz carrier at the same time and interfere with each other.

At the receiver the users can be separated by means of (quasi-)orthogonal codes.

Transmitter 2

Spreading 1

Spreading1

Spreading 2 Receiver

Radio ChannelTransmitter 1

The receiver aims at receiving Transmitter 1 only.

Quasi-orthogonal: it is not necessary to have primary colors at the receiver to separate the user. Red and orange for example can also be distinguished.

Orthogonality between the codes is impossible to maintain after transfer over the radio interface (multi-path on DL, UEs not synchronized on UL )






4.2 Multiple access [cont.]

If a user transmits with a very high power, it will be impossible for the receiver to decode the wanted signal (despite use of quasi-orthogonal codes)

CDMA is unstable by nature and requires accurate power control.

Transmitter 2

Receiver

Radio ChannelTransmitter 1

The receiver aims at receiving Transmitter 1 only.

Spreading 1

Spreading1

Spreading 2

CDMA is instable by nature:

one user may jam a whole cell by transmitting with too high power

need for accurate and fast power control

too many users in one cell would have the same effect

need for congestion control

A CDMA resource has 2 dimensions: the codes and the power. Obviously the power is the limiting factor ; the better we can control the power usage, the more capacity (users) we can allocate.






4.3 Spreading: Channelization and Scrambling

2chc

3chc

1chc

scramblingc

The channelization code (or spreading code) is signal-specific: the code length is chosen according to the bit rate of the signal.

The scrambling code is equipment-specific.

air interface

Modulator

Spreading consists of two steps:

The channelization code (also called spreading code) transforms every data symbol into a number of chips, thus increasing the bandwidth of the signal. The narrowband signal is spread into a wideband signal with a chip rate of 3.84 Mchips/s.

The system must choose the adequate spreading factor to match the bit rate of the narrowband signal.

The spreading factor is directly linked with the length of the channelization code.

The scrambling code does not affect the signal bandwidth: it is only a chip-by-chip operation.

The scrambling code is cell-specific on the downlink and terminal-specific on the uplink.






4.4 Channelization Codes (Spreading Codes)

The channelization codes are OVSF (Orthogonal Variable Spreading Factor) codes:

• their length is equal to the spreading factor of the signal: they can match variable bit rates on a frame-by-frame basis.

• orthogonality enables to separate physical channels:UL: separation of physical channels from the same terminalDL: separation of physical channels to different users within one cell

SF = 1

C ch,1,0 = (1)

C ch,2,0 = (1,1)

C ch,2,1 = (1,-1)

C ch,4,0 =(1,1,1,1)

C ch,4,1 = (1,1,-1,-1)

C ch,4,2 = (1,-1,1,-1)

C ch,4,3 = (1,-1,-1,1)

SF = 4SF = 2 SF = 8

The code tree is shared by several users (usually one code tree per cell)

What is a channelization code?

OVSF (Orthogonal Variable Spreading Factor)

Length: 4-256 chips according to the spreading factor

(in downlink also 512 chips is possible to match very low bit rate)

Number of codes:

The channelization codes can be defined in a code tree, which is shared by several users.

If one code is used by a physical channel, the codes of underlying branches may not be used.

The number of codes is consequently variable: the minimum is 4 codes of length 4, the maximum is 256 codes of length 256.

The channelization code (and consequently the spreading factor) may change on a frame-by-frame basis

How is Code Allocation managed?

The codes within each cell are managed by the RNC.

No need to coordinate code tree resource between different base stations or terminals.

Usually one code tree per cell. If two code trees are used, it is necessary to use the secondary scrambling code.






4.5 Scrambling codes

The scrambling codes provide separation between equipment:

• UL: separation of terminalsNo need for code planning (millions of codes!)There are 224 long and 224 short scrambling codes in uplink

• DL: separation of cellsNeed for code planning between cells (but trivial task)There are only long scrambling codes in downlink(512 to limit the code identification during cell search procedure)

The long scrambling codes are truncated to the 10 ms frame length.

Only one DL scrambling code should be used within a cell.

Another scrambling code may be introduced in one cell if necessary (example : shortage of channelization code), but orthogonality between users will be degraded.

In fact, there are two types of scrambling codes:

Long codes:

Gold codes constructed from a position wise modulo 2 sum of 38400 chip segments of two binary sequences (generated by means of 2 generators polynomials of degree 25)

used with Rake Receiver : the PRACH is constructed from the long scrambling sequences. There are 8192 PRACH preamble scrambling codes in total, divided into 512 groups of 16 each.

Short codes:

Length : 256 chips

used with advanced multi-user detector

likely to be used later

Refer to Technical Specification 3GPP TS 25.213




5 Soft Handover






5 Soft Handover

5.1 Introduction

Principle: As the UEs are separated by codes, they send and receive data at the same time and on the same frequency and one frequency is used in a set of adjacent cells, the soft handover is possible.

A UE is in case of Soft Handover when it is linked to several cells at the same time.

So , in downlink, the UE receives several time the same data and combine them to increase the quality. In Uplink, a Node B can receive the same message from several cells and combines them to increase the quality.

Soft Handover doesn’t exist in GSM, it is not possible because there are different frequencies in a set of adjacent cells.

Interest: As the quality of the signal is increased after the reception, it is possible to use less power. That allows to save the interference level. If this interference level is too high, it is not possible to decode the data and the call is drop.





5 Soft Handover

5.2 Scenarios: Softer Handover

Iu

Core Network

Iubs Iubs

Iur

Iu

Serving RNC

Softer HO : the cells with which the mobile is in communication belong to the same Node B





5 Soft Handover

5.3 Scenarios: Soft Handover intra RNC

Iu

Core Network

Iubs Iubs

Iur

Iu

Serving RNC

Soft HO intra RNC : the cells with which the mobile is in communication belong to different Node Bs and same RNC





5 Soft Handover

5.4 Scenarios: Soft Handover inter RNC

Iu

Core Network

Iubs Iubs

Iu

Serving RNC Drift RNCIur

Soft HO inter RNC : the cells with which the mobile is in communication belong to different Node Bs and different RNC

Serving RNC (SRNC1): on UL it collects information from the Drift RNC and from its own Node-B and performs selection of the signal on a best frame quality basis. On DL it duplicates

Iu-information to Drift RNC and to its own Node-B and recombination of the signal is performed by the UE. There may be only one Serving RNC per UE.

Drift RNC (DRNC2): it performs the routing of information from/to the Serving RNC.

There may be up to 4 Drift RNC(s) per UE.





5 Soft Handover

5.5 Scenarios: SRNC Relocation

Iu

Core Network

Iubs Iubs

Iu

Serving RNC Drift RNCServing RNCIur

SRNC Relocation : the Drift RNC becomes a serving RNC. Se we gain intransmission (no need for Iur for the communication) and delay





In Downlink,

• Scrambling Code

One DL SC per Cell

• Channelization Code

One DL CC per radio link to avoid having the same code sequence on 2 radio links

In Uplink,

• Scrambling Code

One UL SC per UE

• Channelization Code

One UL CC per service (per physical channel).

The UE sends one signal which can be received by several cells.

The UE receives several signals

Conclusion:

5 Soft Handover

5.6 Soft Handover & Code Management

Iu

Core Network

Iubs

Serving RNC

Cell A Cell B

DL SC cellA

DL CC1 user 1

DL SC cellB

DL CC2 user 1

UL SC eqUL CC user





Why do we need soft HO?Imagine that a UE penetrates from one cell deeply into an adjacent cell: it may cause near-far effecthard HO is not a good solution, due to the hysteresis mechanismBetter spatial repartition of the power, so lower interference level

Additional resources due to soft HO:- Additional rake receiver in Node-B- Additional Rake Fingers in UE- Additional transmission links between Node-Bs and RNCs

Soft HO provides Diversity (also called Macro-Diversity), but requires more network resource.

5 Soft Handover

5.7 Cost & Benefit





Soft Handover execution: Soft Handover is executed by means of the following procedures Radio Link Addition (FDD soft-add); Radio Link Removal (FDD soft-drop); Combined Radio Link Addition and Removal. The cell to be added to the active set needs to have information forwarded

by the RNC: Connection parameters (coding scheme, layer 2 information, …) UE ID and uplink scrambling code, Timing information from UE The UE needs to get the following information Channelization & scrambling codes to be used Relative timing information (Timing offset based on CPICH synchro)

5 Soft Handover

5.7 Cost & Benefit [cont.]




6 Rake Receiver






6 Rake Receiver

6.1 Rake Receiver principle

In a CDMA system there is a single carrier which contains all user signals.

Decoding of all these signals by one receiver is only a question of signal processing capacity.

A Rake receiver is capable to decode several signals simultaneouslyin the so called “fingers” and to combine them in order to improve the quality of the signal or to get several services at the same time.

A Rake receiver is implemented in mobile phones and in base stations.

A Rake receiver can provide:- multi-service (via handling of multiple physical channels that are carrying the services)- soft handover- path diversity

“A single carrier”: in fact each operator may use several carriers of 5MHz each (2 in Germany, 3 in France)

The rake receiver can only be used with signals on the same carrier.





6 Rake Receiver

6.1 Rake Receiver principle [cont.]

The components of the multi-code signal are demodulated in parallel each in one “finger” of the Rake Receiver.

The outputs of the fingers:• can provide independent data signals• can be combined to provide a better data signal(s)

Delay 1Code Sequence 1

Code Sequence 2 or 3

Code Sequence 2Delay 2

Delay 3

Data 2

1stFinger

2ndFinger

3rdFinger

Data 1

Multi-code signal

Delay Adjustment

Rake fingers are allocated to the peaks at which significant energy arrives. Update rate: tens of ms

Each finger tracks the fast-changing phase and amplitude values due to fast fading and removes them

Rake Receiver resides in both UE and Node-B.

The numbers of fingers for a Rake Receiver is implementation dependant.





6 Rake Receiver

6.2 Rake Receiver and Multi-Service

As a first approach, we can say:

One service, one code! (*)

Multimedia receiverTransmitter

Spreading 1 Despreading 1

Radio ChannelSpreading 2

Despreading 2

>> Which codes make it possible to >> Which codes make it possible to separate the two signals at the receiver?separate the two signals at the receiver?

* We will see later that it is also possible to multiplex several services on the same code!

Indeed on a dedicated physical channel (which is identified by its spreading code) a user can multiplex several services as long as the total bit rate of the services does not exceed the bit rate of the physical channel.

See subchapter 4 UTRAN/ Physical Layer (Transport Channel Multiplexing)





6 Rake Receiver

6.3 Rake Receiver and soft handover

Soft handover is possible, because the two mobile stations use the same frequency band. The mobile phone need only one transmission chain to decode both simultaneously.

Base Station 2

Spreading 1

Despreading 1&2

Spreading 2 Mobile phone

Radio ChannelBase station 1

>> Which codes make it possible to >> Which codes make it possible to separate the two signals at the separate the two signals at the receiver?receiver?





6 Rake Receiver

6.4 Rake Receiver and Path Diversity

Natural obstacles (buildings, hills…) cause reflections, diffractions and scattering and consequently multipath propagation.

The delay dispersion depends on the environment and is typically:

• 1 µs (300 m) in urban areas • 20 µs (6000 m) in hilly areas

The delay dispersion should be compared with the chip duration 0,26 µs (78 m) of the CDMA system.

If the delay dispersion is greater than the chip duration, the multipath components of the signal can be separated by a Rake Receiver.

In this case, CDMA can take advantage of multipath propagation.

What is multipath propagation?

The signal travels from transmitter to receiver over different paths, due to reflections, diffractions or scattering. Consequently the same signal arrives at the receiver with a little delay.

The chip rate can be considered as the resolution of the CDMA system. It is linked with the 5 MHz carrier.





6 Rake Receiver

6.4 Rake Receiver and Path Diversity [cont.]

Dispersion > Chip durationThe Rake Receiver can provide path diversity to improve the quality of the signal.

ReceiverTransmitter

Spreading

Direct path

Reflected path

ReceiverTransmitter

Spreading Despreading

Direct path

Reflected path

Dispersion <Chip durationThe Rake Receiver cannot provide path diversity.

>> Which codes make it >> Which codes make it possible to separate the two possible to separate the two signals at the receiver?signals at the receiver?

Despreading

Multi-path propagation usually reduces the quality of the signal.

But in most cases a Rake Receiver can take advantage of multi-path to improve the quality of the signal. Indeed the dispersion is often greater than the chip duration.

Note: with IS-95 (cdmaOne), the carrier bandwidth is about 1 MHz and the chip duration is consequently longer: 1 µs (300 m). Multi-path components can not be separated in urban areas with IS-95.




7 Power Control






SIR

7 Power Control

7.1 Why ?

Iub

Serving RNC

Main Problem : If the interference level is to high, it is not possible to decode the signal.

f

P

ISCP or No

PG

Eb

RSCP or Ec

At Node B reception level

SIR

In UTRA/FDD, the power control is a key functionality : the users using

simultaneously the same frequency band interfere each other.

The transmit power must be dynamically adapted in order toEnable to reach the quality of service

Compensate fading occurrences

Avoid interfering other users (and thus decreasing the system capacity)

Two main power control algorithms can be distinguished:

Open-loop power control (UL only)

Closed loop power control (UL/DL)





Physical channels:

• Not associated with transport channels

(Physical signaling)

• Associated with transport channels

• Dedicated channels

• Common channels

7 Power Control

7.2 Different kinds of Power Control

Channel power fixed and set by the operator

Channel power fixed and set by the operator

Open Loop Power Control

Closed & Open Loop power control





7 Power Control

7.3 Open Loop Power Control

The Open Loop Power Control is used to set the initial transmit power when:

• The UE requests a RRC Connection,

• The UE sends the first dedicated radio frame,

• The Node B sends the first dedicated radio frame.

Based on CPICH measurements

Based on UE measurement reports

CPICH

• Initial Access

•First dedicated Radio Frame

Measurement reports

•First dedicated Radio Frame

How is Power Control performed ?

Open loop power control:

it consists for the mobile station of making a rough estimate of path loss by means of a

DL beacon signal and adding the interference level of the Node-B and a constant value.

It’s far too inaccurate and only used to provide a coarse initial power setting of the mobile

station at the beginning of a connection





Iub

RNC

Outer Closed Loop Inner Closed Loop

• SIR Estimation

• Comparison between SIRest and SIRtarget

•Generation of a TCP command: increase or decrease

On each Time slot ! (1500 Hz)

...

”Power down”

”Power up”

”Power down”

”Power ...”

***

***

SIR target

Errormeasurements

The Node-B controls the power of the UE (and vice versa) by performing a SIR estimation (inner loop) and by generating TPC command for each time slot of the radio frame.

The RNC controls parameters of the SIR estimation (outer loop) and set the initial SIR target, defined by the operator and modify it according to the error measurement reports.

Closed Loop Power Control

7 Power Control

7.4 Closed Loop Power Control: Principle

***

***

***

***

Inner Loop (Fast Loop Power Control)

In UL, the serving cells should estimate signal-to-interference ratio SIRest

of the received uplink DPCH. The serving cells should then generate TPC commands and transmit the commands once per slot according to the following rule: if SIRest > SIRtarget

then the TPC command to transmit is "0" , while if SIRest < SIRtarget then the TPC

command to transmit is "1".

Upon reception of one or more TPC commands in a slot, the UE shall derive a single

TPC command, TPC_cmd, for each slot, combining multiple TPC commands if more

than one is received in a slot. TPC_cmd values = +1(power up), -1 (power down), 0

The step size DTPC is under the control of the UTRAN (value = 1 dB or 2 dB)

UE shall adjust the transmit power of the uplink DPCCH with a step of DDPCCH (in dB) which is given by DDPCCH = DTPC TPC_cmd.

The command rate of 1500Hz is faster than any significant change of path loss.

Outer Loop

The RNC checks the quality of the signal using for example a CRC-based approach

(Cyclic Redundancy Check) and uses this result to adjust SIR target for the inner loop.

The big issue is to meet constantly the required quality: no worse and also no better,

because it would be a waste of capacity.

The required quality may change with the multi-path profile (related to the environment)

and with the UE speed.

The outer loop management is handled by the CRNC because a soft HO may be performed.

Frequency of the outer loop: 10-100 Hz typically

Note: in GSM only slow power control is employed (about 2 Hz)





IubAssuming a user using a service.

It is initial SIR target is 3dB.

The error ratio required is 0.01 .

Several error ratio reports are between 0.002 and 0.007

How do the SIR target evolve ?

What is the impact on the user or on the system if the estimated SIR is too high ? Too small ?

7 Power Control

7.4 Closed Loop Power Control: Power Density

RNC ...

”Power up”

”Power ...”

SIR target

Errormeasuremen

ts

ISCP or No

f

P

SIRest

Eb

RSCP or Ec


SIRTarget





What is the behavior of the UE in UL in case of soft handover ?

• The UE takes in to account all the command according to the 3GPP

P(t)=P(t-1) + F(TPC1(t) + TPC2(t))

The function F(TPC(t)) is implemented by the UE manufacturer.

F(TPC(t))=min(TCP1(t), …, TPCi(t))

With i= number of involved Node B

7 Power Control

7.5 UL Closed Loop PC, in case of Soft Handover

Iub

Power up !!! TPC=1

Power down !!! TPC=-1

???

1 2





Iub

What is the behaviour of the Node B involed in the call in DL in case of soft handover ?

• The UE sends the same command for all the Node B involved.

Node Bs must transmit data with the same power for a user

• Due to reception errors their power can shift themselves

A mechanism, the DL Power Balancing, allows to readjust the transmission power of the Node B.

The SRNC selects the best radio link, and readjust, step by step, the transmission power.

P(t) = P(t-1) + Ptpc(t) + Pbal(t)

Power up !!! TPC=1

Power up

Power up

7 Power Control

7.5 DL Closed Loop PC, in case of Soft Handover




8 Capacity, Coverage & Quality






8 Coverage, Capacity & Quality

8.1 Links between Coverage, Capacity and Quality

Example: Increase the quality in UL

How to do ?

• Decrease the error ratio at the Node B level

• So increase the SIR at the Node B level

• So the UEs use more power

Impacts !

• Increase the UL Interference level

• So decrease of the cell size

• And decrease the capacity of the cell.

RNC

Node B

Iub

f

P

SIR

SIR






8.2 Improvement Ways

•AMR speech Codecit enables to switch to a lower bit rate if the mobile is moving out of the cell coverage area: it is a trade-off between quality and coverage.

•Multipath diversityit consists of combining the different paths of a signal (due to reflections, diffractions or scattering) by using a Rake Receiver.Multipath diversity is very efficient with W-CDMA.

•Soft(er) handoverthe transmission from the mobile is received by two or more base stations.

•Receive antenna diversitythe base station collects the signal on two uncorrelated branches. It can be obtained by space or polarization diversity.

•Base stations algorithmse.g. accuracy of SIR estimation in power control process

The AMR (Adaptive Multi-rate) speech codec:

offers 8 AMR modes between 4,75 kbps and 12,2 kbps

is capable of switching its bit rate every 20 ms upon command of the RNC

is located in the UE and in the transcoder (which is located in the CN)






8.3 Typical Values

Quality: The quality is measured with the Block Error Ratio (BLER). Here some example according different services.

Coverage:

• Dense Urban Cell: about 300 meters

• SubUrban Cell: about 1 km

• Rural Cell: 3 km

Capacity:

The main limitation is the interference level due to the WCDMA technology.

But the system is also limited by capacity processing of the Node B and the RNC, by the codes, and by the transmission capacity.

AMR CS64 PS64 PS128 PS384 DCCH

Target BLER

0.001 0.01 0.001 0.01 0.1 0.01 0.01 0.01 0.01

The capacity depends also on:

the radio environment (rural, suburban, indoor)

the terminal speeds

the distribution of the terminals

the load of the cell: trade-off capacity/coverage (breathing cells)

Due to all these parameters, it is harder than in GSM to give a typical value of the capacity of a cell.





Evaluation

Thank you for answeringthe objectives sheet

Objective: To be able to define a Radio Resource in 3G





End of moduleWCDMA for UMTS





Module 3UTRAN Scenario







UTRAN · UA08 9300 W-CDMA R99 Radio PrinciplesW-CDMA R99 Radio Principles · UTRAN Scenario1 · 3 · 2


Blank page


Document History







Module objectives


Build the map of the radio channels(logical, transport and physical channels) from a white paper....











Table of contents


1 Introduction to UTRAN Scenarios 71.1 Introduction 82 Radio Channels Mapping 112.1 Downlink 122.2 Uplink 132.3 DL Channels Framing and Timing 143 Service Request 153.1 System Information Collection 163.1.1 P-SCH & S-SCH 173.1.2 CPICH 193.1.3 System Information Broadcast 203.1.4 Procedure 223.1.5 Radio Channel Mapping: P-CCPCH 233.1.6 Cell Selection Principle 243.2 RRC Connection 253.2.1 UE Status 263.2.2 Procedure: RRC Connection Establishment 293.2.3 Procedure: RRC Connection: RRC Connection Release 303.2.4 How to contact UTRAN: the PRACH 313.3 IMSI Attachment & Location Update 333.3.1 Principles 343.3.2 Procedure: Direct Transfer 353.4 Paging 363.4.1 Procedure 1: UE in Cell-DCH or Cell-FACH 373.4.2 Procedure 2: UE in Idle Mode 383.4.3 Paging: PICH & PCH Radio Channels 394 RAB Establishment 404.1 Admission Control 414.2 Radio Bearer Establishment 434.2.1 Signaling: RAB Establishment 444.2.2 Signaling: Radio Link Setup 454.2.3 Radio Bearer Mapping 464.2.4 Physical Layer Processing 474.2.5 Radio Channels 484.2.6 Radio Channels: Data Processing 494.2.7 Radio Channels: Transport Channel Multiplexing 504.2.8 Radio Channels: DPDCH/DPCCH Channels 515 Mobility Management in Connected Mode 525.1 Soft HO: Active & Monitoring Set 535.2 Soft HO: Events 545.3 Compressed Mode 555.4 Hard HO: Events on other FDD Frequencies 565.5 Hard HO: Events on other GSM Frequencies 576 Exercises 586.1 Scenario Description 596.2 Downlink 606.3 Uplink 61










1 Introduction to UTRAN Scenarios







1.1 Introduction

Iub

Serving RNC

CN Collection of System Information

1. System Information

2. RRC Connection

RRC Connection

IMSI Attachment

3. IMSI Attachment

Paging

4. Paging

The UE is switched on !

How can it retrieve network parameters to request a service?

On the first part, we are going to see how a UE, after it is just switched on, can be able to request a service and to answer to a paging message.

So the first step is to retrieve information about the system. Thank to this system information the UE is able to attach its IMSI and to update its location to the Core Network.

After that the UE can monitor a channel to answer to a paging message or can request itself a service.






1.1 Introduction [cont.]

Iub

Serving RNC

CN

The UE requests a service.

How and in which conditions are the resources required setup ?

Admission Control

? RAB Establishment

RAB

When a UE requests a service, the UTRAN must check if it has enough resources to establish new dedicated channels.

There are after signaling between the UE, the Node B, the RNC and the Core Network to provide to the UE the transfer of the data at the required QoS.

We will also how the data are mapped on the physical channels.






1.1 Introduction [cont.]

Iub

Serving RNC

CN

The UE uses a service and moves !

How UTRAN can provide the service despite the mobility ?

A new radio link is added

Hard Handover on another FDD carrier

Inter RAT Handover

BSCBTS

UTRAN must provide the transfer of the data at the requested QoS to a moving user. So different kinds of handover have been defined.

The Soft Handover, the UE can be linked to several cells using the same fraquency.

The Hard Handover inter FDD carrier and the interRAT HandOver between the 3G and the 2G network if the user loses the 3G coverage.




2 Radio Channels Mapping







2.1 Downlink

Logical Ch

Transport Ch

Physical Ch

AICHNot associated with transport channels PICH CPICH P-SCH S-SCH

PDSCH S-CCPCH P-CCPCHDPDCH

+ DPCCH

DTCH, DCCH CCCH, CTCH

BCHPCHFACHDSCH

Not implemented yet in Alactel-Lucent Solution

PCCH BCCH

DPDCH and DPCCH multiplexed by time

Common Physical ChDedicated Physical Ch

MICH

MSCH, MCCHMTCH

MSCH, MCCH, MTCH map to FACH (only in DL)

DCH1 DCH2

CCTrCH






2.2 Uplink

Logical Ch.

Transport Ch.

Physical Ch.

PRACH PCPCHDPDCH + DPCCH

DTCH, DCCH CCCH

DCH1 RACHDCH2

CCTrCH

CPCH

DPDCH and DPCCH multiplexed by modulation

DedicatedPhysical Ch.

CommonPhysical Ch.






2.3 DL Channels Framing and Timing

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

P-SCH

P-CCPCH

PDSCH

S-CCPCH

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

AICH

DPCH

S-SCH

P-CPICH

PICH

The following applies:

SCH (primary and secondary), CPICH (primary and secondary), P-CCPCH have identical frame timings.

The S-CCPCH timing may be different for different S-CCPCHs, but the offset from the P-CCPCH frame timing is a multiple of 256 chips.

The PICH timing is 7680 chips prior to its corresponding S-CCPCH frame timing, i.e. the timing of the S-CCPCH carrying the PCH transport channel with the corresponding paging information.

AICH access slots #0 starts the same time as P-CCPCH frames with (SFN modulo 2) = 0.

The DPCH timing may be different for different DPCHs, but the offset from the P-CCPCH frame timing is a multiple of 256 chips.




3 Service Request






3 Service Request

3.1 System Information Collection

Principles•The UE synchronizes itself at the slot on the P-SCH

• UE synchronizes itself at the frame level on the S-SCH and retrieves a group of 8 Scrambling codes.

•The UE tests the 8 SC on the CPICH to find the SC of the cell

•The UE decodes the BCH channel to read the system information

•The UE selects the best cell

Iub

Serving RNC

CN

???

Just after the switch on, the UE can decode only the P-SCH and S-SCH if it is on a covered area






3.1.1 P-SCH & S-SCH

P-CCPCH Radio Frame 10 ms

Slot #0 Slot #1 Slot #14

acpP-SCH

S-SCH acs0

…acp acp

acs1 acs14

The SCH is time-multiplexed with the P-CCPCH (which carries the BCH) and consists of 2 sub-channels.

• The Primary SCH (P-SCH) made of always the slot on all the FDD Cells. The UE uses it to acquire the slot synchronization to a cell.

•The Secondary SCH (S-SCH) contains a sequence of 15 codes which identifies the Code Group of the Downlink Scrambling Code (DL SC) of the cell. The UE uses it to acquire the frame synchronization to a cell and to identify the Code Group of the DL SC.

256 chips

Cell Search Procedure (also called synchronization procedure)

3GPP TS 25.214 provides an informative description how it is typically done

Step 1: slot synchronizationIn all the cell of any PLMN, the P-SCH is made of a unique & same primary code sequence of 256 chips repeated at each Time Slot Occurrence. This is typically done with a single matched filter (or any similar device) to the primary synchronisation code which is common to all cells. The slot timing of the cell can be obtained by detecting peaks in the matched filter output.

Step 2: frame synchronization and code-group identificationA S-SCH is made of 15 repetitions of a secondary code sequence of 256 chips (one per Time Slot) transmitted in perfect synchronization with the P-SCH code sequences. The UTRAN uses 64 distinct secondary synchronization code sequences (reused in distant cells of the UTRAN). This is done by correlating the received signal with all possible secondary synchronisation code sequences, and identifying the maximum correlation value. Since the cyclic shifts of the sequences are unique the code group as well as the frame synchronisation is determined.

Each secondary code sequence corresponds to a unique group of 8 possible Primary Scrambling codes

Step 3: (downlink) scrambling code identification

The UE determines the (primary) scrambling code used by the found cell through symbol-by-symbol correlation over the CPICH (pilot) with all codes within the Code Group identified in the step 2 (8 possibilities).

Afterwards the P-CCPCH can be detected and the system- and cell specific BCH information can be read.





Secondary Synchronization Channel

……..

2560 chips

acp

Slot # ?

P-SCH acp

Slot #?

16 6S-SCH

acp

Slot #?

11Group 2Slots 7, 8, 9

256 chips

slot number Scrambling Code Group #0 #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14

Group 0 1 1 2 8 9 10 15 8 10 16 2 7 15 7 16

Group 1 1 1 5 16 7 3 14 16 3 10 5 12 14 12 10

Group 2 1 2 1 15 5 5 12 16 6 11 2 16 11 15 12

Group 3 1 2 3 1 8 6 5 2 5 8 4 4 6 3 7

Group 4 1 2 16 6 6 11 15 5 12 1 15 12 16 11 2

…

Group 61 9 10 13 10 11 15 15 9 16 12 14 13 16 14 11

Group 62 9 11 12 15 12 9 13 13 11 14 10 16 15 14 16

Group 63 9 12 10 15 13 14 9 14 15 11 11 13 12 16 10

The S-SCH also consists of a code, the Secondary Synchronization Code (SSC) that indicates which of the 64 scrambling code groups the cell’s downlink scrambling code belongs to. 16 different SSCs are defined. Each SSC is a 256 chip long complex-valued sequence with identical real and imaginary parts constructed as follows:

z=<b,b,b,-b,b,b,-b,-b,b,-b,b,-b,-b,-b,-b,-b>, where b=<1,1,1,1,1,1,-1,-1,-1,1,-1,1,-1,1,1,-1> corresponds to the first 8 chips of ‘a’ (defined for PSC) and the opposite of its last 8 chips. This iswhy the primary and secondary synchronization codes are orthogonal and can thus be sent in parallel.

There is one specific SSC transmitted in each time slot, giving us a sequence of 15 SSCs. There is a total of 64 different sequences of 15 SSCs, corresponding to the 64 primary scrambling code groups. These 64 sequences are constructed so that one sequence is different from any other one, and different from any rotated version of any sequence. The UE correlates the received signal with the 16 SSCs and identifies the maximum correlation value.

The S-SCH provides the information required to find the frame boundaries and the downlink scrambling code group (one out of 64 groups). The scrambling code (one out of 8) can be determined afterwards by decoding the P-CPICH. The mobile will then be able to decode the BCH. However, by giving scrambling codes from different groups to neighboring cells, the cell search procedure for cell reselections, or for cell acquisition before handovers would not need that third step. The primary and secondary synchronization codes are modulated by the symbol ‘a’, which is worth ‘+1’ when STTD is used, and ‘-1’ when it’s not.

Time Switched Transmit Diversity (TSTD) can be applied to the SCH. It is an optional technique used in UTRAN. A figure above illustrates the structure of the SCH transmitted by the TSTD scheme.






3.1.2 CPICH

CPICH (Common Pilot CHannel)•The pilot carries a pre-defined symbol sequence at a fixed rate.

•It is a reference:

• To aid the channel estimation at the terminal (time or phase reference)

• To perform handover measurements and cell selection/reselection (power reference)

• The UE tests the 8 DL SC of the Group Code. The DL SC which allows to retrieve the pre-define sequence is the DL SC of the cell.

…Slot #0 Slot #1 Slot #14

Pre-defined symbol sequenceSF=256 Tslot=2560 chips 20 bits

The CPICH has the following characteristic

The same channelization code is always used for the CPICH,

The CPICH is scrambled by the primary scrambling code,

There is one and only one CPICH per cell,

The CPICH is broadcast over the entire cell.






3.1.3 System Information Broadcast

The broadcast system information:

• May come from CN, RNC or Node-B.

• Contains static parameters (Cell identity, supported PLMN types...) and dynamic parameters (UL interference level...).

• Is arranged in System Information Blocks (SIB), which group together elements of the same nature.

Some exemple:•SIB1: Core Network Information •SIB3: Cell Selection, Access Restriction•SIB7: UL Interference•SIB11: Measurement

CN

LA, RA …

DL SC, Power Control info

UL interference level

Example of SIB:

MIB: Master Info Block (structure & scheduling of SIBs)

SIB 1: NAS System Information + Timer

SIB 2: URA (not supported) +Timer

SIB 3: Cell Selection/Reselection and Access Restriction

SIB 5: Common channel Information (P-CCPCH, S-CCPCH, RACH) and AICH/PICH power offset

SIB 7: UL Interference and PRACH parameter SIB 11:Measurements

SIB 18:PLMN Identity of neighboring cells






3.1.3 System Information Broadcast [cont.]

The broadcast system information can be carried on BCH which is transmitted permanently over the entire cell.

Transport Ch.

Logical Ch.

Physical Ch.

BCCH

BCH

P-CCPCH

The broadcast system information is made of 128 periodic radio frame. So its period is 1280 ms. There are a Master SIB or MIB and several SIB (System Information Block) organised by domain.

Frame #0 Frame #1 Frame #2

Frame #i-1 Frame #i Frame #i+1

Frame #125 Frame #126 Frame #127

MIB SIB3 SIB11

SIB5 SIB7 MIB

SIB5SIB11 SIB7

…

……

…

Thanks to this channel, the UE is able to retrieve information allowing the request of a RRC connection like the Channelization code used on the uplink common channel

Three parameters are used to set the position of each SIB on the cycle.

SIB_POS: it is the position of the SIB on the cycle (#0 for the MIB for instance)

SIB_REP: it is the repetition of the SIB on the cycle (the MIB is repeated several time on the cycle.

SIB_OFF: If one Radio Frame is not enough to send all the data for a SIB, the rest of the SIB can be send on another radio frame. For example, 2 radio frame after the first one. It is the SIB_OFF.






3.1.4 Procedure

System Information Update Request

Master/Segment Info Block(s), BCCH

modification time

Master/Segment Info Block(s)System Information (BCCH:BCH)

UE Node-B RNC

RRC RRC

NBAP

CN


RRC RRC


RRC RRC

System Information Update Response

NBAP NBAP

>> Why does RRC protocol >> Why does RRC protocol terminate at Nodeterminate at Node--B for BCH B for BCH

(not at RNC)?(not at RNC)?

NBAP






3.1.5 Radio Channel Mapping: P-CCPCH

The Primary CCPCH carries the BCH, which provides system- and cell-specific information (e.g set of uplink scrambling codes)

The P-CCPCH is a fixed rate 30 kbps DL physical channel, which provide a timing reference for all physical channels (directly for DL, indirectly for UL).CCPCH is scrambled under the Primary Scrambling code.

Slot #0 Slot #1 Slot #13 Slot #14Slot #i

SCH

Tslot=2560 chips

20 bits

256 chips

Payload of 18 bits

The P-CCPCH is time multiplexed with the SCH which is transmitted during the first 256 chips.

P-CCPCH timing is identical to that of SCH and CPICH (see 3GPP 25.211).

The P-CCPCH contains no layer 1 information.

Even if the PCCPCH is not transmitted during the 256 first chips of each slot (SCH), the scrambling code is aligned with the PCCPCH frame boundary, i.e the first complex chip of the PCCPCH frame is multiplied with chip number zero of the scrambling code.

The Secondary CCPCH, which is used to carry FACH and PCH information, is scrambled under the Primary scrambling code as well.






3.1.6 Cell Selection Principle

Now, the UE can read the BCH of one cell.

But this cell is not necessary the best because the SCH has been chosen randomly.

The UE compares the cells to be camped on the best one.

There are 2 criterion:

• QRxLev, from the CPICH RSCP, to estimate the reception level.

• Qqual, from the CPICH Ec/No, to estimate the quality of reception. It takes in account the interference level.

When a UE is not connected, like here, and is moving, it has to reselect regularly the best cell for itself. To protect some cells, it is possible to facilitate or not the selection of one cell.

Iub

RNC

CN

???

Aim : find a suitable cell to be camped on

The Cell selection criterion is defined in 3GPP TS 25.304 as:

Squal>0 with Squal=Qqualmeas - Qqualmin

Srxlev>0 Srxlev= Qrxlevmeas – Qrxlevmin - Pcompensation

Parameters :

Qqualmeas: defines the quality of the cell

Measured CPICH Ec/N0

Qqualmin: defines the threshold for the quality of the cell

Configurable in each cell independently

Range: -24 dB to 0 dB (step 1 dB)

Qrxlevmeas : defines the cell Rx Level value

Measured CPICH RSCP

Qrxlevmin : defines the minimum required RX level of the cell

Configurable in each cell independently

Range: -115 dBm to -25 dBm

Pcompensation:

Parameter to take in account the UE capacity





3 Service Request

3.2 RRC Connection

Why?The UE is switched on and has selected a cell.

The UE is in idle mode.

•UTRAN doesn’t know anything about this UE.

•The UE has neither UTRAN identifier nor Scrambling and Channelization code.

The UE can’t exchange any data with UTRAN.

To be known by UTRAN and to use dedicated radio resources, the UE has to be RRC connected.

After, the UE can attach its IMSI or update its location to the Core Network and can request a service

Iub

RNC

CN

RRC Connected





3.2 RRC Connection

3.2.1 UE Status

UE

detached

UE

in idle mode

UE

in connected

mode

RRC Connection Release

RRC Connection Establishment

out of coverage

“just after switch on” process

Including Cell search procedure

Just after the switch on, the UE has to attach its IMSI. Thanks to his procedure the Core Network knows, the UE is on the network and where it is located at the Location or routing area level.

Several sub-status in the connected

mode

To attach its IMSI and update its location the UE has to be in connected mode, so it has to request a RRC Connection

Just after switch on” process contains:

Cell selection (including cell search procedure)

PLMN selection

Attachment procedure (see “Appendix” for more details)

The UE must enter the connected mode to transmit signalling or traffic data to the network

What is the relationship with the states of the mobile phone in GSM?

The two GSM states, idle mode and connected mode, are similar to idle mode and cell_DCH state in UMTS.

What is the relationship with the states of the mobile phone in GPRS?

There is no correspondence between GPRS states (idle, standby and ready) and UMTS states.

Indeed there is no notion of connection on GPRS.





3.2 RRC Connection

3.2.1 UE Status [cont.]

Cell DCH

Cell FACH

URA PCH

Cell PCH

UE

in idle

mode

UE in connected mode

Cell_DCH state

Signalling and traffic data dedicated to the UE (mapped on DCCH and DTCH respectively) are carried on DCH transport channel

Cell_FACH state

Signalling and traffic data dedicated to the UE (mapped on DCCH and DTCH respectively) are carried on RACH (uplink) and FACH (downlink) transport channels

Cell_DCH Cell_FACHNo traffic UL/DL at expiry of timer

Cell_FACH Cell_DCHTraffic volume UL/DL too large

The initial state of the UE is determined by the DCCH established during RRC connection establishment:

if the DCCH is mapped on a DCH, the UE is in cell_DCH state

if the DCCH is mapped on RACH/FACH, the UE is in cell_FACH state

The UE can move from one state to another during the time of the RRC connection.

Transitions between states are:

based on traffic volume measurements and network load

always triggered by UTRAN signalling

Note: in cell_DCH state, the DSCH transport channel can also be used.





3.2 RRC Connection

3.2.1 UE Status [cont.]

Cell_PCH state

No transmission of signalling and traffic data dedicated to the UE (no DCCH and no DTCH)

But the RRC connection is still active (UTRAN keeps RNTI for UE) and UE location at a cell level.

- a DCCH (and possibly a DTCH) can be reestablished very quickly (this procedure is initiated by sending a paging signal PCH)

URA_PCH state

Very similar to cell_PCH state

UTRAN keeps the location of the UE at the URA level (set of UMTS cells)

Cell_PCH Cell_FACH URA_PCHToo many cell reselections

Cell_FACH Cell_PCHNo traffic UL/DL at expiry of timer

2

Cell/URA_PCH Cell_FACHIncoming DL or UL traffic

Cell DCH

Cell FACH

URA PCH

Cell PCH

UE

in idle

mode

UE in connected mode

URA: UTRAN Registration Area (a small set of cells)

Cell_PCH and URA_PCH states are needed for non real time services to optimise usage of codes and battery consumption. It would not be efficient to allocate permanently a DCH which would be used a very low percentage of time (Web application for example)

What is the difference between idle mode, Cell_PCH and URA_PCH states?

In idle mode the location of the UE is not known by the UTRAN, but only by the CN at a Location Area (LA) or Routing Area (RA) level (LA and RA are sets of cells larger than URA).

The paging message PCH must hence be sent in a LA or in a RA when the UE is in idle mode, whereas it only needs to be sent in a cell in Cell_PCH state or in an URA when the UE is in URA_PCH state (hence the paging procedure is much faster).

New in UA8.0 – Direct transition from PCH to DCHFEATURE DESCRIPTIONUntil now, direct RRC state transition from URA_PCH or CELL_PCH to CELL_DCH is supported only for multi-RAB call or upon a mobile terminating CS RAB request. This feature extends the direct transition support to all RAB combinations and to all Always-On upsize triggers.

The decision to go directly to CELL_DCH or through CELL_FACH is based on the Establishment Cause and/or the Traffic Volume Indicator (TVI) included in the Cell Update message





3.2 RRC Connection

3.2.2 Procedure: RRC Connection Establishment

Initial UE identity, Establishment cause, Initial UE capability

1. RRC Connection Request (CCCH:RACH)

UE

RRC RRC

3. Radio Link Establishment

Initial UE identity, RNTI, capability update requirement, TFS, TFCS, frequency, UL scrambling code, power control info

4. RRC Connection Setup (CCCH:FACH)RRC RRC

Integrity information, ciphering information

5. RRC Connection Setup Complete (DCCH:RACH or DCH)RRC RRC

2. Allocate RNTI, Select Level 1 and Level 2 parameters

(e.g. TFCS, scrambling code)

>> Can the UE send user information (e.g voice call) after compl>> Can the UE send user information (e.g voice call) after completing this stage?eting this stage?

Node-B RNC

1. UE initiates set-up of an RRC connection

Initial UE identity: e.g TMSI

Establishment cause: e.g traffic class

2. RNC decides which transport channel to setup (RACH/FACH or DCH) and allocates

RNTI (Radio Network Temporary Identity) and radio resources (e.g TFS, TFCS, scrambling codes) for this RRC connection.

3. A new radio link must be setup.

This is done via a signalling procedure between RNC and Node-B which is managed by NBAP protocol (see“Procedure D” for more detail).

4. Logical, transport and physical channel configuration are sent to the UE.

5. RRC Connection Setup Complete message is sent:

on RACH in case of RRC connection on RACH/FACH (cell_FACH state)

on DCH in case of RRC connection on DCH (cell_DCH state)





Node-B(DRNC)

SRNCDRNCNode-B(SRNC)

3.2 RRC Connection

3.2.3 Procedure: RRC Connection: RRC Connection Release

RRC RRC4. RRC Connection Release (DCCH:DCH )

Cause

RANAP RANAP

1. Iu Release Command

Cause

RANAP RANAP

2. Iu Release Complete

-

3. ALCAP Iu Bearer Release

RRC RRC5. RRC Connection Release Complete (DCCH:DCH )

-

6. Radio Link Deletion



UE CN

In this example, the UE is in macro-diversity on two Node-Bs from two different RNCs. Therefore the UE could only be in cell_DCH state (soft HO is only possible on DCH)

1. The CN initiates the release of RRC connection

2. -

3. SRNC initiates release of Iu Bearer using ALCAP protocol

4. -

5. -

6. SRNC initiates release of radio link (for Node-B of SRNC) using NBAP protocol

7. SRNC requires release of radio link (for Node-B of DRNC) to DRNC using RNSAP protocol

8. DRNC initiates release of radio link (for Node-B of DRNC) using NBAP protocol





3.2 RRC Connection

3.2.4 How to contact UTRAN: the PRACH

For the initial access, the UE has to use a common uplink channel called the PRACH

Every UE uses this channel to request a connection. If 2 UEs request on the time there is collision, and UTRAN receives nothing.

To manage this problem, the UE sends a first message called preamble until it receives a response on a downlink channel called AICH.

After the response on the AICH, the UE sends its message (the request) on the PRACH.

Hello !

Iub

RNC

Preamble on the PRACH

2. Yes !

Response on the AICH

…HELLO!1. I need a connection

PRACH Request : Pre-amble

Preamble on the PRACH

3. Here is my request

PRACH : Message part

PRACH= Physical Random Access Channel

AICH= Acquisition Indicator channel





3.2 RRC Connection

3.2.4 How to contact UTRAN: the PRACH [cont.]

The first preamble is sent with the power P.

The UE resends a preamble until it receives a response on the AICH.

At each time, it increases the power of the preamble by the Power Offset parameter (PO)

UTRAN can’t receive its preamble if:

• The power is not enough high

• There is a collision with another user.

In the message part, there is the RRC connection request.

Preamble

Preamble

Message part

DPp,mPO

Reception of AICH

PO

PPRACH channel





3 Service Request

3.3 IMSI Attachment & Location Update

HLR SGSNMSC/VLR

MSC/VLR SGSN

Iub

RNCThe UE has selected a cell.

It had to declared its identity and its location (LA & RA) to the Core Network.

So, it requests a RRC connection to send to the Core Network information about its situation.

The parameters are mainly the LA, the RA and its IMSI

Initial Attachment

In the selected PLMN, the UE:

selects the best cell according to radio criteria I

initiates attachment procedure on the selected cell

During the attachment procedure (called IMSI attach for CS domain, GPRS attach for PS domain), the UE indicates its presence to the PLMN for the purpose of using services:

authentication procedure

storage of subscriber data from the HLR in the VLR (or in the SGSN for PS domain)

allocation of the TMSI (P-TMSI for PS domain)

The result of the procedure is notified to the UE:

if successful, the UE can access services

if it fails, the UE can only perform emergency calls

LA=Location Area= Set of cells for the CS CN

RA= Routinf Area= Set of cells for the PS CN






3.3.1 Principles

When camping on a cell, the terminal must register its LA and/or its RA.

When the terminal moves across the network, it must update its LA (RA) which is stored in VLR (SGSN) in the Core Network.

LA (RA) Update is performed periodically or when entering a new LA (RA).

HLRSGSNMSC/VLR

Location Area (LA)

Routing Area (RA)

MSC/VLR SGSN

LA and RA are managed on an independent way, but a RA must always be included in one LA (and not be divided into several different LAs).

LA update is performed by the NAS layer MM (Mobility Management) located in UE and in MSC.

RA update is performed by NAS layer GMM (GPRS Mobility Management) located in UE and in SGSN.

In the Core Network, the location information is stored on databases:

HLR (Home Location Register)

It stores the master copy of user’s service profile, which consists of information on allowed services, forbidden roaming areas,… and which is created when a new user subscribes to the system.

The HLR also stores the serving system (MSC/VLR and/or SGSN) where the terminal is located.

VLR (Visitor Location Register)

It serves the terminal in its current location for CS services and holds a copy of the visiting

user’s service profile.

It stores the Location Area (LA) where the terminal is located.

SGSN (Serving GPRS Support Node)

It serves the terminal in its current location for PS services and holds a copy of the visiting

user’s service profile.

It stores Routing Area (RA) where the terminal is located.






3.3.2 Procedure: Direct Transfer

RANAP RANAP1. Direct Transfer

CN Domain Indicator, NAS PDU

RRC RRC

2. Downlink Direct Transfer (DCCH:FACH or DCH)

NAS message

UE Node-B SRNC CN

Use mainly for the IMSI attachment, location update and the authentification between the UE and the Core Network

RANAP RANAP2’. Direct Transfer

CN Domain Indicator, NAS PDU

RRC RRC

1’. Uplink Direct Transfer (DCCH:RACH or DCH)

CN node indicator, NAS message

UE must be in cell_FACH or in cell_DCH states.





3 Service Request

3.4 Paging

Core Network

Called number

HLRMSC/VLR MSC/VLR

Location Area

Some one is calling me, I request a RRC

connection

Principle

Paging message with the IMSI of

the called UE

Iub

RNC

Iub

RNC

Iub

RNC

If the UE is in idle mode. UTRAN doesn’t know them and can just forward the paging message coming from the Core Network to all the cell belonging to the Location ou Routing Area.

The UE monitors periodically a channel to check if it is paged or not.

If the UE is connected the Core Network knows the Serving RNC of the UE and sends the paging message just to this RNC.

The RNC knows the UE uses the dedicated or common channel to send the paging message.





3.4 Paging

3.4.1 Procedure 1: UE in Cell-DCH or Cell-FACH

RANAP RANAP1. Paging

CN Domain Indicator, UE identity, Paging cause

RRC RRC2. Paging Type 2 (DCCH:FACH or DCH)

In this case the UE is already connected and is using a service (voice call, web-browsing …). The Core Network knows the situation of the UE and mainly its Serving RNC. The CN contacts directly the Serving RNC.

The RNC doesn’t use the PCCH and the PCH but the channel used for the UE, dedicated or common, according to the status of the UE.

UE Node-B SRNC CN

UE is in cell_FACH or in cell_DCH states:

1. CN initiates the paging of a UE to Serving RNC

2. Paging of UE with Paging Type 2 (on DCCH) using the existing RRC connection





3.4 Paging

3.4.2 Procedure 2: UE in Idle Mode

RRC RRC2. Paging Type 1 (PCCH:PCH)

RRC RRC2. Paging Type1 (PCCH:PCH)


CN Domain Indicator, UE identity, Paging cause


Idem

When the mobile is in idle mode, UTRAN doesn’t know where it is located and the Core Network knows its location at the LA or RA level. UTRAN uses the PCCH and the PCH radio channels.

UE 1 Node-B1UE 2 Node-B2 RNC1 RNC2 CN

UE is in idle mode:

1. CN initiates the paging of a UE over a LA (RA in PS domain) spanning, for example, two RNCs.

2. Paging of UE with Paging Type 1

LA: Location Area, RA: Routing Area (see subchapter “5.8 Mobility Management”)

A similar procedure applies to UE in cell_PCH or in URA_PCH states.





3.4 Paging

3.4.3 Paging: PICH & PCH Radio Channels

The UE doesn’t watch the S-CCPCH.

It watches the PICH (Page Indicator Channel) at regular and defined interval and look for its PI, for Paging Indicator.

The PI is based on the IMSI. Several UEs can have the same PI.

When the UE find its PI on the PICH, it watches the S-CCPCH to check if it is for it and what is the cause.

Then it requests on RRC connection to have a RAB.

Transport Ch

Iub

RNC

PICHS-CCPCH

PCH

PCCH Logical Ch

Physical Ch

MAC

Physical layer

In RNC

In Node B

PICHS-CCPCH

Paging message

PI

PI

PI

...

The period of the cycle is between 4 and 4096 radio frames. That means the UE can monitor the PICH every X seconds, with X between 40 ms and 40,96 seconds. If the period is too short the UE uses too much power if the period is 40 s, the delay is really long.

It is a trade-off between the delay and the consumption.

To determine the radio frame number into the cycle and the Paging Indication, the UE uses its IMSI and others parameters send on the SIB.




4 RAB Establishment






4 RAB Establishment

4.1 Admission Control

According to the previous part “WCDMA in UMTS”, if the interference level at the Node B level is too high, the Node B can’t decode all the signal. The size of the cell decreases. The interferences are due to several causes:

• The radio environment and the load of the adjacent cells,

• Some users use too much power, the power control manages this problem,

• There are too many users on the cells

UTRAN has to check if there is enough UL radio resource

Iub

RNC

f

P

ISCP = NoSIR

PG

Eb

RSCP = Ec


SIR too small to retrieve the message

2 others questions before adding a new user : Is there sufficient DL radio resource andsufficient processing resources ?

If the CAC (Call Admission Control) has not been passed,

For CS services, the call can’t be established.

For PS services, the UTRAN may try assigning a RB with a lower bit rate. There are different level of bit rates than can be used a given requested RAB. The Node B tries to assign first the highest, and then goes to the lower rates, as long as the RAC rejects the Radio Link Reconfiguration.





4 RAB Establishment

4.1 Admission Control [cont.]

Is there sufficient UL Radio Resource -> Rx CAC

If UL interference level + estimated new user contribution < threshold

Then Rx RAC ok

Is there sufficient DL Radio Resource -> Tx CAC

If Total DL Tx Power + estimated new user contribution < threshold

Then Tx RAC ok

Is there sufficient processing resource -> Processing CAC

3 main points are checked:

• the channelization codes

•The Baseband load

•The number of users and radio links

Is there sufficient Iub Bandwidth -> Iub CAC

Iub Bandwidth is checked

CAC = Call Admission Control





4 RAB Establishment

4.2 Radio Bearer Establishment

We have seen how a UE, after the switch on, can collect system information, update its location, request a RRC Connection and a service, can be paged and how UTRAN allows it to use services. Now how is established the RAB ?

Signaling

Core NetworkIub

Node B

RNC

UTRAN

RABRadio Bearer

Logical Channel

RLC

Transport Channel

MAC

Physical Channel

Phy.

RLC Mode: Tr., UM or AM and retransmission parameter for AM

TTI, TFS, TFCS, CRC, FEC, Coding Rate, Rate Matching

Frequency, Power, Channelization & Scrambling codes

RRC

Configured by

Iu Bearer RAB

RAC = Radio Access Control






4.2.1 Signaling: RAB Establishment

RANAP RANAP1. RAB Assignment Request

RAB parameters, User plane mode, Transport Address, Iu

Transport association

2. ALCAP Iu Data Transport Bearer Setup

3. Radio Link Establishment

RRC RRC4. RB Setup (DCCH:FACH or DCH )

TFS, TFCS...

RRC RRC5. RB Setup Complete (DCCH:RACH or DCH )

-

RANAP RANAP6. RAB Assignment Response

-

The UE is RRC connected and has requested a service.

UE Node-B SRNC CN

Can the UE send user information (e.g voice call) just after Radio Access Bearer establishment?

YES : At the end of this signaling procedure, a RAB has been assigned to the UE to carry user information. The RAB is mapped on the RB which has been set up. The RB is mapped on DTCH: RACH/FACH or DCH.






4.2.2 Signaling: Radio Link Setup

Cell id, TFS, TFCS, frequency, UL scrambling code, power control info

Radio Link Setup RequestNBAP NBAP

Signaling link termination, transport layer addressing info

Radio Link Setup ResponseNBAP NBAP

Downlink synchronisationIub-FP Iub-FP

Uplink synchronisationIub-FP Iub-FP

Start RX

Start TX

>> Are NBAP, ALCAP and RRC messages carried on the same transpor>> Are NBAP, ALCAP and RRC messages carried on the same transport bearers on Iub?t bearers on Iub?

ALCAP Iub Data Transport Bearer Setup

Node-B SRNC


This procedure is used in many RRC procedures, e.g RRC connection establishment (Procedure C1), Radio Bearer Set-up (Procedure F1), soft HO (Procedure G)…

In this procedure:

a radio link is set up by the RNC on the Node-B side using the NBAP protocol

(a similar task is performed on the UE side using RRC protocol, see e.g. procedure C1)

a terrestrial link (AAL2 bearer) is setup on Iub interface using ALCAP protocol






4.2.3 Radio Bearer Mapping

We have seen how a UE, after the switch on, can collect system information, update its location, request a RRC Connection and a service, can be paged and how UTRAN allows it to use services. Now how are established the RAB ?

Core NetworkIub

Node B

RNC

UTRAN

RABRadio Bearer

Logical Channel

RLC

Transport Channel

MAC

Physical Channel

Phy.

RLC Mode: Tr., UM or AM and retransmission parameter for AM

TTI, TFS, TFCS, CRC, FEC, Coding Rate, Rate Matching

Frequency, Power, Channelization & Scrambling codes

RRC

Configured by

Iu Bearer RAB







4.2.4 Physical Layer Processing

Convolutional coding, Turbo coding

10 ms frame duration15 time slots

CCtrCH

DPDCH, DPCCH, PRACH...

Channelization codesScrambling codes

QPSK

Channel Coding

Radio Frame Segmentation

Transport Channel Multiplexing

Physical Channel Mapping

Spreading

Modulation

Physical Channels spread over 5 MHz bandwidth

Layer 1

The physical layer belongs to control plane and to user plane.

Physical layer main functions:

Multiplexing/de-multiplexing of transport channels on CCTrCH (Coded Composite Transport Channel) even if the transport channels require different QoS.

Mapping of CCTrCH on physical channels

Spreading/de-spreading and modulation/demodulation of physical channels

RF processing (3 GPP 25.10x)

Frequency and time (chip, bit, slot, frame) synchronization

Measurements and indication to higher layers (e.g. FER, SIR, interference power, transmit power, etc.)

Open loop and Inner loop power control

Macro-diversity distribution/combining and soft handover execution






4.2.5 Radio Channels

Assuming a UE a video call service. What happens in Uplink ?

RLC

MAC

Physical Layer

Radio Bearer

Logical Ch. DTCH

Transport Ch. DCH

Physical Ch. DPDCH/DPCCH

RLC parameters

RAB :64 kbps

MAC parametersMode : Transparent because it is a real time service

CRC = 16 bits, FEC = Turbo Code Coding Rate = 1/3, TTI= 20 ms, TFS=(0*640, 2*640 bits)

640

640

640

640

640

640

TTI

How many radio frame are necessary to send all this data ?

CN

UE

The RB 20 (1st column ) corresponds to the Video Call.






4.2.6 Radio Channels: Data Processing

Assuming a UE a video call service. What happens in Uplink ?

#1 #2

#1 #2

Transport Blocks

CRC attachment

Tr Bl concatenation

Turbo coding (1/3)

Tail Bit Attachment

1 st interleaving

Radio Frame Segmentation

Rate matching

640 bits 16

(640+16)*2=1312 bits

1312*3=3936 bits

1312*3=3936 bits6

3942 bits

#1 #21971 1971

#1 #21971 +Nrm 1971 +Nrm

Can you deduce the SF ?

And the value of Nrm ?

First, the 16 CRC bits are added at each transport block.

Then the transport block are concatenated.

The turbo coding consist of adding a lot of redundant bits to be able to detect and correct errors.

Before the interleaving some bits are added. The purpose of the interleaving is to avoid to have big packet of errors at the reception.

Finally the data are segmented by 2, because the TTI=20 ms and a radio frame is 10 ms.

At the end to fill the radio frame, Nrm bits are added.






4.2.7 Radio Channels: Transport Channel Multiplexing

Assuming a UE a video call service and on the same time sends on a e-mail.

How can it be possible to send 2 different services on the same physical channel ?

Several transport channels can be time-coordinated to be multiplexed on a CCTrCH before mapping on one physical channel

MAC

TFC Selection

L1

TrCH Multiplexing

Phy. Ch. Mapping

CCTrCH

Physical Channel

DCH1 DCH2

Example:

TFS (DCH1)={(0*640); (4*640)}

TFS(DCH2)={(1*0); (1*39); (1*42); (1*55); (1*65)}

TFCS={(0*640); (1*0)}; {(0*640); (1*39)}; {(0*640); (1*42)}; {(0*640); (1*55)}; {(0*640); (1*65)}; {(1*640); (1*39)}; {(1*640); (1*42)}

MAC selects TFC inside TFCS.

There is one TFCS per CCTrCH

Transport Format

Transport Format Combination

TFS= Transport Format Set

TFCS=Transport Format Combination Set

TF=Transport Format






4.2.8 Radio Channels: DPDCH/DPCCH Channels

Uplink

Downlink



Data : user data, RRC Signaling & NAS Signaling DPDCH

DPCCH Pilot TFCI FBI TPC

Multiplexed by the modulation

Data1 TPC Data2 TFCI Pilot

DPDCH DPCCH DPDCH DPCCH DPCCH

Time-multiplexed

Why are DPDCH and DPCCH time-multiplexed in DL(and not transmitted simultaneously as in UL)?

Discontinuous transmission can cause audible interference to audio equipment close to the terminal (e.g hearing aids), which is a disturbance for user.

In UL the transmission is always continuous, because there is at least the DPCCH which is transmitted. The user will not be disturbed.

In DL the transmission may be discontinuous, but it is no problem (no user at the base station).

Note: The downlink DPDCH/DPCCH physical channels are called the DPCH physical channel.




5 Mobility Management in Connected Mode







5.1 Soft HO: Active & Monitoring Set

Iub

RNC

The RNC manages the Active Set and builds the Monitoring Set.

The Monitoring Set is built from the information of topology and design in the RNC.

The Active Set is managed from the event send by the UE to the RNC.

Cell in the Active Set

Cell in the Monitoring Set

The maximum number of cells in the monitoring set is 32.

The maximum number of cells in the active set is set from the Office Data, between 3 and 6.

The monitored set is built for each UE by the RNC from the neighboring list. The RNC selects the best cells in this list for the monitored cells.






5.2 Soft HO: Events

Iub

RNC

There are 3 events for the soft handover. The value measured is the CPICH Ec/No.

The event 1a is triggered when the CPICH Ec/No of a monitored cells is above a certain threshold.If the event is fulfilled the cell is added in the active set

The event 1b is triggered when the CPICH Ec/No of a active cell is below a certain threshold.If the event is fulfilled the cell is removed from the active set

The event 1c is triggered when the active set has reached its maximum size and the CPICH Ec/No of a monitored cells is better than a cell belonging to the active set.If the event is fulfilled the candidate cell replaces the cell in the active set Cell in the Active Set

Cell in the Monitoring Set

The simplified formula to trigger an 1a event is :

10log(Mnew) > 10log (MBest) – R1a

Where:

Mnew is a measurement on the candidate cell about the quality of reception.

Mbest is a measurement on the best cell in the active set about the quality of reception.

R1a is the “Reporting Range”.

Best Cell

T1 -> Event 1a

R1a

CPICH Ec/N0

Time

Candidate Cell

T0






5.3 Compressed Mode

Iub

RNC


Cell in the Monitored Set, same FDD frequency

Cell in the Monitored Set, other FDD frequency

Cell in the Monitored Set, GSM cell

Most of the UEs are not dual receivers. And they need to perform measurements on other frequencies.

So UTRAN has to free a time window to perform these measurements on other FDD frequencies or on GSM frequencies.

Time interval to measure other frequencies

Compressed mode method available according to the 3GPP TS 25.212

compressed mode methods:

By puncturing : the rate matching is applied for creating a transmission gap in one or two frames (not in UL)

Reducing the SF by 2

Compressed frames can be obtained by higher layer scheduling. Higher layers then set restrictions so that only a subset of the allowed TFCs are used in a compressed frame. The maximum number of bits that will be delivered to the physical layer during the compressed radio frame is then known and a transmission gap can be generated






5.4 Hard HO: Events on other FDD Frequencies

Iub

RNC





There are 4 events to watch the UMTS cell with other FDD frequencies

The event 2d_cm is triggered when the quality of on the current frequency is below a certain quality. The compressed mode is launched.

The event 2b is triggered when the quality of the current frequency is below a certain threshold and the quality on an other frequency is above a certain threshold

The event 2f is triggered when the quality on the current frequency is above a certain threshold. The compressed mode is deactivated.






5.5 Hard HO: Events on other GSM Frequencies

Iub

RNC





2 causes can trigger an hard HO toward the GSM system:

• Some bad radio conditions

• due to the service requested

The event 2d_cm is triggered when the quality of on the current frequency is below a certain quality. The compressed mode is launched.

The event 3a is triggered when the quality on the current FDD frequency is below a certain threshold and the quality on the GSM is above another threshold.

The event 3c is triggered when the service requested can be managed by the GSM, the voice typically.

Alcatel-Lucent HHO’s algorithm (called iMCTA – Intelligent Milti carrier Traffic Allocation) doesn’t use the 3A and 3C events.




6 Exercises






6 Exercises

6.1 Scenario Description

Objectives:Rebuilt the channels mapping, Logical, Transport and Physical channelsfrom a scenario to guide you with the 2 next pages

Scenario:

• The UE switches on in a covered area

• The UE collects information about the system

• The UE requests a RRC connection to declare its location and releases the RRC connection

• The UE receives a paging message to receive an e-mail

• UTRAN establishes a RAB and is in the DCH_Cell State

• As the traffic is not large, the UE passes to the FACH_Cell State

Be careful, following this scenario, some channels are missing.Which are the missing channels ?





6 Exercises

6.2 Downlink

Logical Ch.

Transport Ch.

Physical Ch.





6 Exercises

6.3 Uplink

Logical Ch.

Transport Ch.

Physical Ch.





End of moduleUTRAN Scenario





Module 4MBMS Radio Principles







UTRAN · UA08 9300 W-CDMA R99 Radio PrinciplesW-CDMA R99 Radio Principles · MBMS Radio Principles1 · 4 · 2


Blank page


Document History







Module objectives


Describe the Multimedia Broadcast Multicast Service (MBMS) feature Explain the new NEs and interfaces in the UMTS architecture List the new channels and the functions Explain the OVSF Code Tree Configuration with MBMS Explain the MBMS service area concept Describe the features: “Iub Transport bearer sharing“ and “Selective/soft

Combining”











Table of contents


1 MBMS introduction 71.1 MBMS principles 81.2 Architecture overview 92 MBMS UTRAN new functionalities 102.1 MBMS new channels 112.2 MBMS data flow through RLC, MAC and L1 122.3 OVSF Code Tree Configuration with MBMS (1/2) 133 MBMS features in UA7.1 143.1 Service areas 153.2 Iub transport bearer sharing 163.3 Native IP Iub and MBMS 183.4 Selective/soft Combining 193.5 Summary MBMS in UA07 20






Switch to notes view!





1 MBMS introduction






1 MBMS introduction

1.1 MBMS principles

FEATURE DESCRIPTION MBMS Broadcast allows operators to

broadcast Multimedia content to all mobiles in any cell(s) of the network

FEATURE VALUE Efficient data delivery method to many

users

For the operators, this means reduction of the TCO for additional data revenue streams (e.g.. Mobile TV, advertising, etc.) and improved subscriber loyalty.

DEPENDENCIES UE and Core Network MBMS support

Unicast: data is sent as many

times as users in the network

TV program

Broadcast: data is sent only once within network

TV program

Same content to Multiple users :Bandwidth efficiency, capacity gain, CAPEX saving

Multimedia Broadcast Multicast Service (MBMS) is a 3GPP Release 6 feature

Enhanced MBMS Broadcast Service allows operators to broadcast Multimedia content (text, images, audio, video, ..) to all mobiles in any cell(s) of the UMTS network.

Two modes of operation:

Broadcast mode (point-to-multipoint)

Multicast mode (point-to-multipoint or point-to-point) (expected later than UA07)

Data is transmitted from one single source to multiple terminals in a broadcast service area.

Optimization of Iub resources

Support of MBMS on Iub over IP

Use of IP multicast in case of native IP Iub (not available yet, expected later than UA07)

Transport Bearer Sharing.

Customer BenefitsEfficient delivery method to many users. Compared to CBS, MBMS-broadcast allows high data rates and multimedia services. Moreover, it is possible for UEs to receive this data in any state

For the operators, this means additional data revenue streams (e.g. Mobile TV, advertising, etc..) and improved subscriber loyalty

Transport bearer sharing unloads the transport network.





1 MBMS introduction

1.2 Architecture overview

UTRAN

GnIu-PS

CN PS domain

Node B

BSS

Gn

Gr

Uu

LTE Access eCN

eNode B

BSS

Gi

Gmb

Control Plane

The BM-SC performs the following functions:

Membership function Session and transmission function Proxy and transport function Service announcement function Security function

RNC GGSN3G-SGSN

2G-SGSN

Gr

BM-SC

aGW

HLR

ContentProvider

MBMS is provided over the PS

Domain Other Network entities (GGSN, SGSN and RAN)

are impacted to support MBMS

A new UMTS entity (BM-SC) has been

introduced

Multicast / Broadcast

source

Bearer Plane

The boundary of the MBMS Bearer Service is the Gmb and Gi reference points: the former provides access to control plane and the later the bearer plane.Gmb:Signaling between GGSN and BM-SC is exchanged at Gmb reference point. This represents the network side boundary of the MBMS Bearer Service from a control plane perspective. This includes user specific Gmbsignaling and MBMS bearer service specific signaling.

MBMS bearer service specific Gmb signaling:

The GGSN establishes the MBMS bearer context and registers at BM-SC

The GGSN or the BM-SC releases the MBMS bearer context and deregisters the GGSN from the BM-SC

The BM-SC indicates session start and stop to the GGSN including session attributes like QoS and MBMS service area.

User specific Gmb signaling:

BM-SC authorizes the user specific MBMS multicast service activation (join) at the GGSN

GGSN reports to the BM-SC the successful user specific MBMS multicast activation (join) to allow the BM-SC to synchronize the BM-SC MBMS UE context with the MBMS UE contexts in the SGSN and GGSN

GGSN reports to BM-SC when a user specific MBMS multicast service is released or deactivated (e.g. at implicit detach), it makes this report in order to synchronize the BM-SC MBMS UE context with the MBMS UE contexts in the SGSN and GGSN.

The BM-SC initiates the deactivation of a user specific MBMS bearer service when the MBMS user service is terminated.BM-SC functions for different MBMS bearer services may be provided by different physical network elements. Further, MBMS bearer service specific and user specific signaling for the same MBMS bearer service may also be provided by different physical network elements. To allow this distribution of BM-SC functions, the Gmb protocol must support the use of proxies to correctly route the different signaling interactions in a manner which is transparent to the GGSN.




2 MBMS UTRAN new functionalities







2.1 MBMS new channels

New Logical channels MSCH (MBMS PTM Scheduling Channel) mapped on FACH Used to notify the scheduling of MBMS sessions

MCCH (MBMS PTM Control Channel) mapped either on FACH Carries control plane information

MTCH (MBMS PTM Traffic Channel) mapped on FACH Delivers user plane information

MAC-m (Media Access Control MBMS) functionality Handling of the mapping of MTCH, PCCH to the appropriate FACH In charge of Scheduling/Buffering/Priority handling of MBMS transmissions Located at RNC

New Physical channel MICH (MBMS notification Indication Channel) SF=256 S-CCPCH physical channel Used to indicate MBMS information availability on MCCH

PTM – Point-To-Multipoint

MCCH - MBMS PTM Control ChannelCarries control plane information between network and UEs

Is mapped over a separate FACH, i.e., not sharing with other logical channels

Can share SCCPCH

MTCH - MBMS PTM traffic channelCarries user plane traffic

Is mapped to one FACH transport channel

TCTF field in MAC header is always used

One MTCH is configured for each MBMS service

MSCH - MBMS PTM scheduling channelCarries transmission schedule between network and UEs

Is mapped over a separate FACH

Shares SCCPCH with MTCH

Used for DTX






2.2 MBMS data flow through RLC, MAC and L1

One MAC entity for each cell

Node B

FACH

PTM radio bearer

MTCH

FP FP FP

RLC

Cell1 Cell2 Cell3

S-CCPCH S-CCPCH S-CCPCH

FP FP FP

MAC-c/m MAC-c/m MAC-c/m

RNC







2.3 OVSF Code Tree Configuration with MBMS (1/2)

25

6

12

8

6432

168…

P-CPICH; Cch256,0

1

00

1

2

3

4

5

6

P-CCPCH; Cch256,1Aich; Cch256,2Pich; Cch256,3

S-CCPCH (for DTCH/DCCH/CCCH/BCCH); Cch64,1

S-CCPCH (for PCCH); Cch128,4

S-CCPCH (for MCCH); Cch256,10MICH; Cch256,11

HS-SCCH; Cch128,6

MICH & MCCH

The codes for the MICH (SF=256) and the MCCH (SF=256 or 128) are allocated at the top of the tree at MBMS cell setup.

Example: DL OVSF code allocation with configuration B with MBMS and without CBS




3 MBMS features in UA7.1







3.1 Service areas

MBMS Service Area (SA): area in which a specific MBMS session is made available.The MBMS RAB establishment involves the establishment of a number of RB for MTCH (one per cell). The service content is broadcast within a set of cells ‘MBMS service area’.

Service Area N

Service Area 1

The operator can define the MBMS Service Areas in a flexible way. The service area can be as small as one cell, and one cell can belong to up to 8 service areas.

RNC

Service Area 2 IP Network






3.2 Iub transport bearer sharing

MBMS Transport in 3GPP Release 6

RNC

NodeBn

RNC

IP Network

Node B2

Node B1

Node Bn






3.2 Iub transport bearer sharing [cont.]

MBMS first Transport Optimization in 3GPP Release 7 Iub Transport bearer sharing

Node B2 Node Bn

Node B1

Iub transport efficiency is also ensured over several cells of the same Node B: a single flow is used on a shared Transport bearer if the same content is sent to multiple cells of the same Node B.

IP Network

RNC

Transport bearer sharingMBMS over a single FACH is supported in UA7.1.

It is activated per Iub with OAM parameter IsTransportBearerSharingForMBMSSupported.

This improvement applies only for PTM transmission, using FACH transport channel. It concerns only MTCH (MBMS traffic channel) and not MCCH (MBMS control channel)

Without this improvement, the MBMS RAB establishment involves the establishment of several MTCH flows per Node B (one MTCH flow per cell)

With this improvement, the MBMS RAB involves the establishment of only one MTCH flow for multiple cells in one Node B, or more precisely of one FACH DATA frame for MTCH per Node B, (instead of one FACH data frame for MTCH per cell) and thus enables to improve Iub bandwidth efficiency

There is a restriction in iCEM and xCEM, that the number of cells that can share a TB is <= 3, and all those cells have to be handled by the same BBU (i.e. those cells are in the same LCG or Local Cell Group). So for a (6sector 2carrier) BTS configuration, we would need 4 MBMS Broadcast Groups, each having a separate TB, so 4TBs in sum.






3.3 Native IP Iub and MBMS

In case of a native IP Iub, all traffic, including the MBMS PTM traffic is carried on IP/Ethernet in RNC and in Node B Default DSCP used for MBMS PTM are configurable in RNC, configured values have to be consistent with global IP QoS strategy on IubDefault DSCP used for MBMS PTM Streaming and MBMS PTM Backgroundare different.







3.4 Selective/soft Combining

There is less PA power needed in a cell when combining is possible. Thus, during an ongoing MBMS session, the RNC will periodically adjust power levels according to the neighboring situation.

To improve quality of received trafficSoft combining: L1 combining MTCH payload is received from the primary cell and neighboring cells, and is

combined at L1 (similar to DHO) Require transmission synchronization from the RNC

Selective combining: L2 combining RLC provides buffering of PDUs before the re-assembly unit PDUs received in sequence are sent to the re-assembly unit, otherwise held in

the DAR buffer

DAR – Duplicate Avoidance and Reordering

DHO – Diversity Handover


In order to improve L1 performance Selective/Soft Combining is supported.

Selective combiningSelective Combining is the mode where the UE performs RLC re-ordering based on RLC PDU numbering and on combining data streams from different cells

To support selective combining:

One RLC entity per MBMS service utilizing PTM transmission and per cell group

All cells in the cell group are under the same CRNC, i.e. Iur support is not considered.

Soft/Selective combining is only possible with same SF & user rate.






3.5 Summary MBMS in UA07

MBMS Broadcast main target is Mobile TV application

MBMS Broadcast can be supported on any carrier(s), and can be dedicated or mixed with other services

Mobility is supported in any mobile state

64, 128, and 256 kbps data rates can be supported

MBMS traffic may be transmitted in parallel to other services

Iub optimization

MBMS Broadcast main target is Mobile TV application

Session running for long/unlimited time

High number of users interested in the service

MBMS Broadcast can be supported on any carrier(s), and can be dedicated or mixed with other services

FLC/FLD (Frequency Layer Convergence/Divergence) is supported

Mobility is supported in any mobile state

Idle, Cell-FACH, URA/Cell-PCH, and Cell-DCH state

64, 128, and 256 kbps data rates can be supported

Streaming @ 64, 128 or 256 kbps, Background @ 64 kbps

Lower rates currently not defined in 3GPP TR 25.993

MBMS traffic may be transmitted in parallel to other services

Whether the UE will be able to actually receive MBMS will only depend on its own capabilities

Note : MBMS capabilities are not provided to UTRAN

Iub optimization

When the same content is sent to multiple cells of the same Node B, trunking allows to conveyed on the same flow: thus, instead of one FACH data frame per cell, only one FACH data frame is sent to a Node B.





Module Summary

Having completed this module, you should be able to:

Describe the MBMS feature Explain the new NEs and interfaces in the UMTS architecture List the newly introduced channels and the functions Explain the OVSF Code Tree Configuration with MBMS Explain the MBMS service area concept Describe the features: „ Iub Transport bearer sharing“ and „Selective/soft

Combining”





End of moduleMBMS Radio Principles





Module 5Glossary







UTRAN · UA08 9300 W-CDMA R99 Radio PrinciplesW-CDMA R99 Radio Principles · Glossary1 · 5 · 2


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Document History







Abbreviations and Acronyms

Switch to notes view!# 16-QAM 16 – Quadrature Amplitude Modulation 3GPP 3rd Generation Partnership Project A AAL ATM Adaptation Layer ACELP Algebraic Code Excited Linear Prediction ACK Acknoledgement ADN Abbreviated Dialling Number AID Alarm Instance Identification ALCAP Access Link Control Application Part AMPS Advanced Mobile Phone System AMR Adaptive Multi Rate ANRU Antenna Network and multi-carrier Receiver UMTS ANSI American National Standard Institute

(USA) ARIB Association of Radio Industries and Business (Japan) ATC ATM Traffic Contract ATM Asynchronous Transfer Mode B BB Base Band BCCH Broadcast Control Channel BER Bit Error Rate BHCA Busy Hour Call Attempts BLER Block Error Rate BMC Broadcast Multicast Control BM-SC Broadcast Multicast Service Centre BM-IWF Broadcast Multicast Inter-Working Function BPMT Node B Performance Monitoring Tool BSC Base Station Controller BSS Base Station (sub)System BTS Base Transceiver Station BWC Bandwidth Control C CAC Connection Admission Control CAMEL Customised Application for Mobile CAPEX CAPital EXpenditure Enhanced Logic CC Call Control CCCH Common Control Channel CCO Cell Change Order CCT Call Context Template CCTrCH Coded Composite Transport Channel CDMA Code Division Multiple Access CDR Call Data Record CDV Cell Delay Variation CLR Cell Loss Ratio CM Configuration Management

CN Core Network CONT Controller CPCH Common Packet Channel CPCS Common Part Convergence Sub-layer CPS Command Part Sub-layer CPU Central Processing Unit CQI Channel Quality indicator CRC Cyclic Redundant Check CS Circuit Switched CS Convergence/Adaptation to Services

(ATM) CTCH Common Traffic Channel CTD Cell Transfer Delay D DAR Duplicate Avoidance and Reordering DB Debug DCA Dynamic Channel Allocation DCCH Dedicated Control Channel DCH Dedicated Channel DCN Data Communication Network DHO Diversity HandOver DHT Diversity HandOver Trunk DL Downlink DPCH Dedicated Physical Channel DPCCH Dedicated Physical Control Channel DPDCH Dedicated Physical Data Channel DRAC Dynamic Resource Allocation Control DRNC Drift RNC DS Direct Sequence DSCH Downlink Shared CHannel DTCH Dedicated Traffic Channel E E-DCH Enhanced Dedicated CHannel EDGE Enhanced Data rates for GSM Evolution EFR Enhanced Full Rate E-GSM Enhanced GSM E-GPRS Enhanced GPRS EM Element (or Equipment) Manager ERAN EDGE Radio Access Network (all-IP)

ETSI European Telecommunication Standard Institute

F FACH Forward Access Channel FAD Function Access Domain FBI Feed-Back Information FDD Frequency Division Duplex FDL File Download (EM application) FDMA Frequency Division Multiple Access FER Frame Error Rate FTP File Transfer Protocol FW Firmware





Abbreviations and Acronyms [cont.]

Switch to notes view!G GCRA Generic Cell Rate Algorithm GERAN GSM/EDGE Radio Access Network GGSN Gateway GPRS Support Node GMSC Gateway MSC GMSK Gaussian Minimum Shift Keying GP Granularity Period GPRS General Packet Radio Service GSM Global System for Mobile

Communications GTP GPRS Tunneling Protocol GTP-U GPRS Tunneling Protocol-User Plane GUI Graphical User Interface H HCS Hierarchical Cell Structure HHO Hard HandOver HIF High speed Interface HLR Home Location Register HO HandOver HSDPA High Speed Downlink Packet Access HS-DPCCH High Speed Dedicated Physical Control

CHannel. HS-DSCH High Speed Downlink Shared CHannel HSS Home Subscriber Service HS-SCCH High Speed Shared Control CHannel HSUPA High Speed Uplink Packet Access HPLMN Home PLMN I IMEI International Mobile Equipment Identity IMS IP Multimedia Subsystem IMSI International Mobile Subscriber Identity IMT International Mobile Telecommunication IMT-DS Direct Sequence IMT-MC Multi Carrier IMT-SC Single Carrier IMT-TC Time Code IOT Inter Operability Tests IOR Interoperable Object Reference IP Internet Protocol IR Incremental Redundancy ISC Internetworking Services Card ISDN Integrated Services Digital Network Itf-b Interface Node B - OMC-R Itf-r Interface RNC - OMC-R ITU International Telecommunication Union Iub Interface Node B - RNC Iur Interface RNC - RNC Iu-CS Interface RNC - CN Circuit Switch

Iu-PS Interface RNC - CN Packet Switch K Kbps Kilo Bit per Second L L1, L2, L3 Layer , Layer 2, Layer3 LA Local Area LAC Local Area Code LAN Local Area Network LCS LoCation Services LED Light Emitting Diode LLC Logical Link Control LoS Line of Sight LM Load Module LMT Local Maintenance Terminal LIF Low speed Interface LQC Link Quality Control M MAC Medium Access Control MAC-hs Medium Access Control - High Speed MAP Mobile Application Part MBMS Multimedia Broadcast Multicast Service MBS Multi-standard Base Station (UTRAN) MBS Maximum Burst Size (ATM) MCCH MBMS PTM Control Channel MCR Minimum Cell Rate MICH MBMS notification Indication Channel MIMO Multiple Input / Multiple Output MM Mobility Management MMUX MAC Multiplexer MSC Mobile Switching Centre MSCH MBMS PTM Scheduling Channel MSP Multiple Subscriber Profile MTCH MBMS PTM Traffic Channel MTP3 Message Transfer Part level 3 MTP-3B Message Transfer Part level 3 Broadband N NACK Non-Acknoledgement NAS Non Access Stratum NAD Network Access Domain NBAP Node-B Application Part NE Network Element N/E Normal/ Emergency NEM New element manager NEM-B Network Element Manager for Node B NEM-R Network Element Manager for RNC NM Combined EM and SNM NML Network Management Layer NMS Network Management System NPA Network Performance Analyser NTP Network Time Protocol






Switch to notes view!O OAM Operation And Maintenance O&M Operation And Maintenance OD Office Data ODMA Orthogonal Division Multiple Access ODT Office Data Tool ODTM Office Data Tool Macro OFDM Orthogonal Frequency Division

Multiplexing OMC-R Operation & Maintenance Centre - Radio OPEX OPerational EXpenditures ORB Object Request Broker OS Operating System OSA Open Service Architecture OTDOA Observed Time Difference of Arrival OTSR Omni directional Tx / Sectorised Rx OVSF Orthogonal Variable Spreading Factor P PCCH Paging Control Channel PCR Peak Cell Rate PCU Packet Control Unit PDA Personal Digital Assistant PDC Personal Digital Cellular (2G Japan) PDP Packet Data Protocol PDU Protocol Data Unit PFS Proportional Fair Scheduling PLMN Public Land Mobile Network PM Performance Measurement (O&M) PRACH Physical Random Access Channel PS Packet Switched PSK Phase Shift Keying PSTN Public Switched Telephone Network PTM Point-To-Multipoint PTP Precision Timing Protocol Q QoS Quality of Service QPSK Quadrature Phase Shift Keying R R5 Release 5 R’99 Release ’99 RA Routing Area RAB Radio Access Bearer RAC Routing Area Code RAC Radio Admission control RACH Random Access Channel RLC Radio Link Control RNC Radio Network Controller RNO Radio Network Optimiser RNS Radio Network Sub-System RNSAP RNS Application Part RNTI Radio Network Temporary Identity RP Reporting Period RAID Redundant Array Independent (or Inexpensive) Disk

RAN Radio Access Network RANAP RAN Application Part RB Radio Bearer RR Round Robin RF Radio Frequency RPMT RNC Performance Monitoring Tool RRC Radio Resource Control RRM Radio Resource Management RV Redundancy Version S SAC Service Area Code SAP Service Access Point SAR Segmentation And Re-assembly SAT SIM Application Toolkit SC Short Cell SC System Configuration SCF System Configuration File SCR Sustainable Cell Rate SCTP Stream Control Transmission Protocol SDH Synchronous Digital Hierarchy SF Spreading Factor SGSN Serving GPRS Support Node SHO Soft HandOver SIR Signal to Interference Ratio SL Scheduling List SMS Short Message Service SNMP Simple Network Management Protocol SPU Signaling Processing Unit SQL Structured Query Language SRNC Serving RNC SSCOP Service Specific Connection Oriented

Protocol SSCP Signaling Connection Control Part STM Synchronous Transfer Mode STTD Space Time transmit diversity SU Signalling Unit






Switch to notes view!T TC Transcoder TC Transmission Convergence (ATM) TCP Transport Control Protocol TD-CDMA Time Division & CDMA TDD Time Division Duplex TDMA Time Division Multiple Access TEU Transmitter Equipment UMTS TF Transport Format TFC Transport Format Combination TFCI Transport Format Combination Indicator TFCS Transport Format Combination Set TFRC Transport Format Resource Combination TFRI Transport Format Resource Indicator TFS Transport Format Set TIA Telecommunication Industry Association

(USA) TMA Tower Mounted Amplifier TMN Telecommunication Management

Network TMSI Temporary Mobile Subscriber Identify TPA Transmit Power Amplifier TPC Transmission Power Control TQL Query Language for semi-structured data TRE Transceiver Equipment (GSM) TRX Transceiver (UMTS V1) TS Tunning Session TSAL Tunning Session Application Log TSTD Time Switch Transmit Diversity TTA Telecommunication Technology

Association (Korea) TTI Transmission Time Interval U UARFCN UTRA Absolute Radio Frequency Channel Number UDP User Datagram Protocol UE User Equipment UICC UMTS Integrated Circuit Card UL Uplink UMTS Universal Mobile Telecommunication System URA UTRAN Registration Area USB Universal Serial Bus USIM UMTS Subscriber Identity Card USM User Service Manager USSD Unstructured Supplementary Service Data UTRA UMTS Radio Access Network (ETSI) UTRA Universal Radio Access Network (3GPP) UTRAN UMTS Terrestrial Radio Access Network UWCC Universal Wireless Communications

Committee

V VC Virtual Channel VCI Virtual Channel Identifier VHE Virtual Home Environment VLR Visitor Location Register VoIP Voice over IP VP Virtual Path VPI Virtual Path Identifier VSWR Voltage Standing Wave Ratio W W3C World Wide Web Consortium WAP Wireless Application Protocol W-CDMA Wide-band Code Division Multiple

Access WIM WAP Identity Module X XML Extensible Mark-up Language





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