009 WCDMA UTRAN Interface and Signaling Procedure

7/27/2019 009 WCDMA UTRAN Interface and Signaling Procedure

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WCDMA UTRAN Interface and SignalingProcedure

Huawei Technologies Co., Ltd.

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WCDMA UTRAN Interface and Signaling Procedure Confidentiality level: Customer

Mexico Training Center Confidential information of Huawei. Page 2/68

Revision Record

Date Version Change descriptionAuthor

03-06-2007 1B Victor Toledo





Table of Contents

1 UTRAN Network Overview .....................................................................................................7

1.1 The position of UTRAN in WCDMA Network.............................................................. 7

1.2 UMTS Construction.....................................................................................................71.3 UMTS Structure...........................................................................................................91.4 Uu Interface...............................................................................................................101.5 General Protocol Model for UTRAN Terrestrial Interface .........................................161.6 Iu-CS Interface .........................................................................................................191.7 Iu-PS Interface...........................................................................................................211.8 Iub Interface...............................................................................................................221.9 Iur Interface ...............................................................................................................23

2 Basic Concepts About UTRAN.............................................................................................24

2.1 SRNC and DRNC......................................................................................................242.2 CRNC .........................................................................................................................252.3 RAB, RB and RL ........................................................................................................262.4 UE Working Modes and States..................................................................................26

2.5 UE states figure..........................................................................................................313 UTRAN Signaling Procedure................................................................................................33

3.1 Cell Setup ..................................................................................................................333.2 System Information Broadcast..................................................................................343.3 Paging ......................................................................................................................393.4 Call Process ..............................................................................................................413.5 Handover ..................................................................................................................55









Objectives

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

Understand UTRAN interface and structure

Understand the definitions about UTRAN network elements

Understand UTRAN signaling procedure









1 UTRAN Network Overview

1.1 The Position of UTRAN in WCDMA Network

Figure 1. - WCDMA Network.

Service manager layer

Service convergence layer

Radio access layer

1.2 UMTS Construction

Figure 2. - WCDMA Network Architecture.





WCDMA network architecture shown in picture above

UE (User Equipment)

The User Equipment (UE) consists of two parts:

1. The mobile equipment (ME) is the radio terminal used for radio communicationover the Uu interface

2. The UMTS Subscriber Identity Module (USIM) is the equivalent smartcard toSIM in GSM. It holds the subscriber identity, performs authentication algorithm,stores authentication and encryption keys, etc.

UTRAN (UMTS Terrestrial Radio Access network)

The UTRAN consists of one or several Radio Network Subsystem (RNS), eachcontaining one RNC and one or several NodeB.

1. NodeB

The NodeB is the correspondent element to the BTS in GSM.

2. RNC

The Radio Network Controller (RNC) owns and controls the radio resources ofthe connected NodeB.

CN (Core Network)

Core network (CN) includes a lot of equipments such as MSC ,HLR,SGSN,GGSN,AUC,VLR etc.

Interfaces

Iu interface

The Iu interface connects the UTRAN to the CN and is split in two parts. TheIucs is the interface between the RNC and the circuit switched domain of the CN.The Iups interface is the interface between the RNC and the packet switched domainof the CN.

Uu interface

The Uu interface is the WCDMA radio interface with in UMTS. It is the interfacethrough which the UE accesses the fixed part of the network.





1.3 UMTS Structure

Figure 3. - UMTS Structure.

UTRAN (UMTS Terrestrial Radio Access network) structure

The UTRAN consists of one or several Radio Network Subsystem ( RNS ) ,eachcontaining one RNC and one or several NodeB.

Interfaces

Iu interface

The Iu interface connects the UTRAN to the CN and is split in two parts. TheIucs is the interface between the RNC and the circuit switched domain of the CN.The Iups interface is the interface between the RNC and the packet switched domainof the CN.

Uu interface

The Uu interface is the WCDMA radio interface with in UMTS. It is the interfacethrough which the UE accesses the fixed part of the network.





Iub interface

The Iub interface connects the NodeB and the RNC. Contrarily to GSM, thisinterface is fully open in UMTS and thus more competition is expected.

Iur interface

This RNC-RNC interface was initially designed in order to provide inter RNC softhandover, but more features were added during the development.

1.4 Uu Interface

Figure 4.- Protocol Stack for Uu.

The radio interface (Uu) is layered into three protocol layers:

The physical layer (L1).

The data link layer (L2).

The network layer (L3).





The layer 1 supports all functions required for the transmission of bit streams onthe physical medium. It is also in charge of measurements function consisting inindicating to higher layers, for example, Frame Error Rate (FER), Signal toInterference Ratio (SIR), interference power, transmit power, … It is basicallycomposed of a “layer 1 management” entity, a “transport channel” entity, and a

“physical channel” entity.

The layer 2 protocol is responsible for providing functions such as mapping,ciphering, retransmission and segmentation. It is made of four sublayers: MAC(Medium Access Control), RLC (Radio Link Control), PDCP (Packet DataConvergence Protocol) and BMC (Broadcast/Multicast Control).

The layer 3 is split into 2 parts: the access stratum and the non access stratum.The access stratum part is made of “RRC (Radio Resource Control)” entity and“duplication avoidance” entity. The non access stratum part is made of CC, MM parts.

Not shown on the figure are connections between RRC and all the other protocollayers (RLC, MAC, PDCP, BMC and L1), which provide local inter-layer controlservices.

The protocol layers are located in the UE and the peer entities are in the node Bor the RNC.`

The radio interface (Uu) is spitted into 2 plane, left is control plane ,right is userplane ,control plane transfer control massage such as signaling, measurementcontrol. User plane transfers user data such as speech, packet data etc.

Many functions are managed by the RRC layer. Here is the list of the mostimportant:

Establishment, re-establishment, maintenance and release of an RRCconnection 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 incharge of a specific connection towards a UE, it acts as the Serving RNC.

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

Assignment, reconfiguration and release of radio resources for the RRCconnection: it handles the assignment of radio resources (e.g. codes, sharedchannels). RRC communicates with the UE to indicate new resources allocationwhen handovers are managed.





Paging/Notification: it broadcasts paging information from network to UEs.

Broadcasting of information provided by the non-access stratum (CoreNetwork) or access Stratum. This corresponds to “system information” regularly

repeated.

UE measurement reporting and control of the reporting: RRC indicates whatto 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 specification from 3GPP.

The RLC’s main function is the transfer of data from either the user or the controlplane over the Radio interface. Two different transfer modes are used: transparent and non-transparent. In non-transparent mode, 2 sub-modes are used:acknowledged or unacknowledged.

RLC provides services to upper layers:

data transfer (transparent, acknowledged and unacknowledged modes),

QoS setting: the retransmission protocol (for AM only) shall be configurable bylayer 3 to provide different QoS,

Notification of unrecoverable errors: RLC notifies the upper layers of errorsthat cannot be resolved by RLC.

The RLC functions are:

Mapping between higher layer PDUs and logical channels,

Ciphering: prevents unauthorized acquisition of data; performed in RLC layer fornon-transparent RLC mode,

Segmentation/reassembly : this function performs segmentation/reassembly ofvariable-length higher layer PDUs into/from smaller RLC Payload Units. The RLCsize is adjustable to the actual set of transport formats (decided when service isestablished). Concatenation and padding may also be used.





Error correction: done by retransmission (acknowledged data transfer modeonly).

Flow control: allows the RLC receiver to control the rate at which the peer RLC

transmitting entity may send information.

MAC services include:

Data transfer: service providing unacknowledged transfer of MAC SDUsbetween peer MAC entities.

Reallocation of radio resources and MAC parameters: reconfiguration ofMAC functions such as change of identity of UE. Requested by the RRC layer.

Reporting of measurements: local measurements such as traffic volume andquality indication are reported to the RRC layer.

The functions accomplished by the MAC sublayer are listed above. Here’s aquick explanation for some of them:

Priority handling between the data flows of one UE: since UMTS ismultimedia, a user may activate several services at the same time, having possiblydifferent profiles (priority, QoS parameters...). Priority handling consists in setting theright transport format for a high bit rate service and for a low bit rate service.

Priority handling between UEs: use for efficient spectrum resources utilizationfor bursty transfers on common and shared channels.

Ciphering: to prevent unauthorized acquisition of data. Performed in the MAClayer for transparent RLC mode.

Access Service Class (ACS) selection for RACH transmission: the RACHresources are divided between different ACSs in order to provide different priorities

on a random access procedure.





PDCP

UMTS supports several network layer protocols providing protocol transparencyfor the users of the service.

Using these protocols (and new ones) shall be possible without any changes toUTRAN protocols. In order to perform this requirement, the PDCP layer has beenintroduced. Then, functions related to transfer of packets from higher layers shall becarried out in a transparent way by the UTRAN network entities.

PDCP shall also be responsible for implementing different kinds of optimizationmethods. The currently known methods are standardized IETF (Internet EngineeringTask Force) header compression algorithms.

Algorithm types and their parameters are negotiated by RRC and indicated to PDCP.

Header compression and decompression are specific for each network layerprotocol type.

In order to know which compression method is used, an identifier (PID: PacketIdentifier) is inserted. Compression algorithms exist for TCP/IP, RTP/UDP/IP.

Another function of PDCP is to provide numbering of PDUs. This is done iflossless SRNS relocation is required.

To accomplish this function, each PDCP-SDUs (UL and DL) is buffered andnumbered. Numbering is done after header compression. SDUs are kept untilinformation of successful transmission of PDCP-PDU has been received from RLC.PDCP sequence number ranges from 0 to 65,535.

BMC (broadcast/multicast control protocol)

The main functions of BMC protocol are:

Storage of cell broadcast message. the BMC in RNC stores the cell broadcast

message received over the CBC-RNC interface for scheduled transmission.

Traffic volume monitoring and radio resource request for CBS. On theUTRAN side, the BMC calculates the required transmission rate for the cellbroadcast service based on the messages received over the CBC-RNC interface,and requests appropriate .CTCH/FACH resources from RRC.





Scheduling of BMC message. The BMC receives scheduling informationtogether with each cell broadcast message over the CBC-RNC interface. Based onthis scheduling information, on the UTRAN side the BMC generates schedulemessage and schedules BMC message sequences accordingly. On the UE side ,theBMC evaluates the schedule messages and indicates scheduling parameters to

RRC, which are used by RRC to configure the lower layers for CBS discontinuousreception.

Transmission of BMC message to UE. The function transmits the BMCmessages according to the schedule

Delivery of cell broadcast messages to the upper layer. This UE functiondelivers the received non-corrupted cell broadcast messages to the upper layer.

The layer 1 (physical layer) 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 tothese services is through the use of transport channels via the MAC sub layer.

These services are provided by radio links which are established by signalingprocedures. These links are managed by the layer 1 management entity. Oneradio 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 physicalsublayers. The entire processing (channel coding, interleaving, etc.) is done by thetransport sublayer in order to provide different services and their associated QoS.The physical sublayer is responsible for the modulation, which corresponds to theassociation of bits (coming from the transport sublayer) to electrical signals that canbe carried over the air interface. The spreading operation is also done by thephysical sublayer.

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





1.5 General Protocol Model for UTRAN Terrestrial Interface

The structure is based on the principle that the layers and planes are logicallyindependent of each other.

Figure 5. - General protocol model for WCDMA RAN interfaces.

Protocol structures in UTRAN terrestrial interfaces are designed according to thesame general protocol model. This model is shown in above slide. The structure isbased on the principle that the layers and planes are logically independent of eachother and, if needed, parts of the protocol structure may be changed in the futurewhile other parts remain intact.

Horizontal Layers

The protocol structure consists of two main layers, the Radio Network Layer (RNL) and the Transport Network Layer (TNL). All UTRAN-related issues arevisible only in the Radio Network Layer, and the Transport Network Layer representsstandard transport technology that is selected to be used for UTRAN but without any

UTRAN-specific changes.





Vertical Planes

Control Plane

The Control Plane is used for all UMTS-specific control signaling. It includes theApplication Protocol (i.e. RANAP in Iu, RNSAP in Iur and NBAP in Iub), and theSignaling Bearer for transporting the Application Protocol messages. The ApplicationProtocol is used, among other things, for setting up bearers to the UE (i.e. the RadioAccess Bearer in Iu and subsequently the Radio Link in Iur and Iub). In the threeplane structure the bearer parameters in the Application Protocol are not directly tiedto the User Plane technology, but rather are general bearer parameters. TheSignaling Bearer for the Application Protocol may or may not be of the same type asthe Signaling Bearer for the ALCAP. It is always set up by O&M actions.

User Plane

All information sent and received by the user, such as the coded voice in a voicecall or the packets in an Internet connection are transported via the User Plane. TheUser Plane includes the Data Stream(s), and the Data Bearer (s) for the DataStream(s). Each Data Stream is characterized by one or more frame protocolsspecified for that interface.

Transport Network Control Plane

The Transport Network Control Plane is used for all control signaling within the

Transport Layer. It does not include any Radio Network Layer information. It includesthe ALCAP protocol that is needed to set up the transport bearers (Data Bearer) forthe User Plane. It also includes the Signaling Bearer needed for the ALCAP. TheTransport Network Control Plane is a plane that acts between the Control Plane andthe User Plane. The introduction of the Transport Network Control Plane makes itpossible for the Application Protocol in the Radio Network Control Plane to becompletely independent of the technology selected for the Data Bearer in the UserPlane.

About AAL2 and AAL5

Above the ATM layer we usually find an ATM adaptation layer (AAL). Its functionis to process the data from higher layers for ATM transmission.

This means segmenting the data into 48-byte chunks and reassembling theoriginal data frames on the receiving side. There are five different AALs (0, 1, 2, 3/4,and 5). AAL0 means that no adaptation is needed. The other adaptation layers havedifferent properties based on three parameters:





• Real-time requirements;

• Constant or variable bit rate;

• Connection-oriented or connectionless data transfer.

The usage of ATM is promoted by the ATM Forum. The Iu interface uses twoAALs: AAL2 and AAL5.

AAL2 is designed for the transmission of connection oriented, real-timedata streams with variable bit rates.

AAL5 is designed for the transmission of connectionless data streamswith variable bit rates.

RNL Control Plane Application Protocol

Figure 6.- RNC Protocols.





RANAP is the signalling protocol in Iu that contains all the control informationspecified for the Radio Network Layer.

RNSAP is the signalling protocol in Iur that contains all the control information

specified for the Radio Network Layer.

NBAP is the signalling protocol in Iub that contains all the control informationspecified for the Radio Network Layer.

RRC is the signalling protocol in Uu that locate in the Uu interface layer 3

1.6 Iu-CS Interface

Figure 7.- IU-CS interface Protocols.





Protocol Structure for Iu CS

The Iu CS overall protocol structure is depicted in above slide. The three planesin the Iu interface share a common ATM (Asynchronous Transfer Mode) transport

which is used for all planes. The physical layer is the interface to the physicalmedium: optical fiber, radio link or copper cable. The physical layer implementationcan be selected from a variety of standard off-the-shelf transmission technologies,such as SONET, STM1, or E1.

Iu CS Control Plane Protocol Stack

The Control Plane protocol stack consists of RANAP, on top of Broadband (BB)SS7 (Signaling System #7) protocols. The applicable layers are the SignalingConnection Control Part (SCCP), the Message Transfer Part (MTP3-b) and SAAL-NNI (Signaling ATM Adaptation Layer for Network to Network Interfaces). SAAL-NNI

is further divided into Service Specific Coordination Function (SSCF), ServiceSpecific Connection Oriented

Protocol (SSCOP) and ATM Adaptation Layer 5 (AAL) layers. SSCF and SSCOPlayers are specifically designed for signaling transport in ATM networks, and takecare of such functions as signalling connection management. AAL5 is used forsegmenting the data to ATM cells.

Iu CS Transport Network Control Plane Protocol Stack

The Transport Network Control Plane protocol stack consists of the SignallingProtocol for setting up AAL2 connections (Q.2630.1 and adaptation layer Q.2150.1),on top of BB SS7 protocols. The applicable BB SS7 are those described abovewithout the SCCP layer.

Iu CS User Plane Protocol Stack

A dedicated AAL2 connection is reserved for each individual CS service.





1.7 Iu-PS Interface

Protocol Structure for Iu PS

The Iu PS protocol structure is represented in above slide. Again, a commonATM transport is applied for both User and Control Plane. Also the physical layer isas specified for Iu CS.

Figure 8.- IU-PS Interface Protocols.

Iu PS Control Plane Protocol Stack

The Control Plane protocol stack again consists of RANAP, and the same BBSS7-based signaling bearer as described in Section 5.4.1.1. Also, as an alternative,an IP-based signaling bearer is specified. The SCCP layer is also used commonly

for both. The IP based signaling bearer consists of M3UA (SS7 MTP3 – UserAdaptation Layer), SCTP (Simple Control Transmission Protocol), IP (InternetProtocol), and AAL5 which is common to both alternatives. The SCTP layer isspecifically designed for signaling transport in the Internet. Specific adaptationlayers are specified for different kinds of signaling protocol, such as M3UA for SS7-based signaling.





Iu PS Transport Network Control Plane Protocol Stack

The Transport Network Control Plane is not applied to Iu PS. The setting up ofthe GTP tunnel requires only an identifier for the tunnel, and the IP addresses for

both directions and these are already included in the RANAP RAB Assignmentmessages.

Iu PS User Plane Protocol Stack

In the Iu PS User Plane, multiple packet data flows are multiplexed on one orseveral AAL5 PVCs. The GTP-U (User Plane part of the GPRS Tunneling Protocol)is the multiplexing layer that provides identities for individual packet data flow. Eachflow uses UDP connectionless transport and IP addressing.

1.8 Iub Interface

Figure 9.- Iub Interface Protocols.

The Iub interface is the terrestrial interface between NodeB and RNC. Theprotocol stack for the Iub is shown in the above slide. The Radio Network Layerdefines procedures related to the operation of the NodeB. The transport NetworkLayer defines procedures for establishing physical connections between the NodeBand the RNC.





The Iub application protocol, NodeB application part (NBAP) initiates theestablishment of a signaling connection over Iub. It is divided into two essentialcomponents, NBAP common for defining the signaling procedures across thecommon signaling link and NBAP dedicated for the dedicated signaling link. Thissplit is due to the fact that the NodeB is defined as having a common part and anumber of dedicated parts (each controlling a traffic connection).

NBAP-C is used for signaling that initiates a UE context for a dedicated UE orsignals that are not related to specific UE. Examples of NBAP-C procedure are cellconfiguration, handling of common channels and radio link setup.

NBAP-D signaling is used for signaling relating to a specific UE context. Theinitial request to NodeB from the RNC such as Radio link setup for a contextactivation uses NBAP-C, but once the context has been set up ,NBAP-D is usedfrom then. Examples of NBAP-D functions are: addition, reconfiguration and releaseof radio links for one UE context.

SAAL is an ATM Adaptation Layer that supports communication betweensignalling entities over an ATM link.

The user plane Iub Frame Protocol (FP), defined the structure of the frames andthe basic in band control procedure for every type of transport channel. There areDCH-FP, RACH-FP, FACH-FP, HS-DSCH FP and PCH FP.

1.9 Iur Interface

Figure 10.- Iur Interface Protocols.

Iur interface connects two RNCs. The protocol stack for the Iur is shown in aboveslide.

The RNSAP protocol is the signaling protocol defined for the Iur interface.





2 Basic Concepts about UTRAN

SRNC/DRNC

Figure 11. - Serving RNC and Drift RNC.

Inside the UTRAN, the RNCs of the Radio Network Subsystems can beinterconnected together through the Iur. Iu(s) and Iur are logical interfaces. Iur canbe conveyed over direct physical connection between RNCs or virtual networksusing any suitable transport network.

For each connection between User Equipment and the UTRAN, One RNC is theServing RNC. When required, Drift RNCs support the Serving RNC by providingradio resources. The role of an RNC (Serving or Drift) is on a per connection basisbetween a UE and the UTRAN.





CRNC

Figure 12.- Controlling Radio network Controller.

Then what is CRNC? CRNC is related to a specific NodeB (or Cell).





RAB, RB and RL

Figure 13.- The concept of RAB, RB and RL.

RAB: The service that the access stratum provides to the non-access stratum fortransfer of user data between User Equipment and CN.

RB: The service provided by the layer2 for transfer of user data between UserEquipment and Serving RNC.

RL: A "radio link" is a logical association between single User Equipment and asingle UTRAN access point. Its physical realization comprises one or more radio

bearer transmissions.

UE Working Modes and States

Idle mode

Connected mode

Cell_DCH.

Cell_FACH.

Cell_PCH. URA_PCH.

The connected mode is entered when the RRC connection is established. TheUE leaves the connected mode and returns to idle mode when the RRC connectionis released or at RRC connection failure.





Idle Mode

The UE has no relation to UTRAN, only to CN. For data transfer, a signallingconnection has to be established.

UE camps on a cell

It enables the UE to receive system information from the PLMN.

When registered and if the UE wishes to establish an RRC connection,it can do this by initially accessing the network on the control channelof the cell on which it is camped.

UE can receive "paging" message from control channels of the cell.

It enables the UE to receive cell broadcast services.

The idle mode tasks can be subdivided into three processes:

PLMN selection and reselection;

Cell selection and reselection;

Location registration.

When a UE is switched on, a public land mobile network (PLMN) is selected andthe UE searches for a suitable cell of this PLMN to camp on.

The NAS shall provide a list of equivalent PLMNs, if available, that the AS shalluse for cell selection and cell reselection.

The UE searches for a suitable cell of the chosen PLMN and chooses that cell toprovide available services, and tunes to its control channel. This choosing is knownas "camping on the cell". The UE will, if necessary, then register its presence, bymeans of a NAS registration procedure, in the registration area of the chosen cell.

If the UE finds a more suitable cell, it reselects onto that cell and camps on it. Ifthe new cell is in a different registration area, location registration is performed.

Connected Mode

When at least one signalling connection exists, the UE is in connected modeand there is normally an RRC connection between UE and UTRAN. The UEposition can be known on different levels:

UTRAN Registration Area (URA) levelThe UE position is known on URA level. The URA is a set of cells





Cell levelThe UE position is known on cell level. Different transport channeltypes can be used for data transfer.

Common transport channels (RACH / FACH, DSCH, CPCH).

Dedicated transport channels (DCH).

In connected mode, the UE is assigned a Radio Network Temporary Identity(RNTI) to be used as UE identity on common transport channels. Two types of RNTIexist. The Serving RNC allocates an s-RNTI for all UEs having an RRC connection.The combination of s-RNTI and an RNC-ID is unique within a PLMN. c-RNTI isallocated by each Controlling RNC through which UE is able to communicate onDCCH. c-RNTI is always allocated by UTRAN when a new UE context is created toan RNC, but the UE needs its c-RNTI only for communicating on common transport

channels.

Within connected mode the level of UE connection to UTRAN is determined bythe quality of service requirements of the active radio bearers and the characteristicsof the traffic on those bearers.

The UE-UTRAN interface is designed to support a large number of UEs usingpacket data services by providing flexible means to utilize statistical multiplexing.Due to limitations, such as air interface capacity, UE power consumption andnetwork h/w availability, the dedicated resources cannot be allocated to all of thepacket service users at all times.

Variable rate transmission provides the means that for services of variable ratethe data rate is adapted according to the maximum allowable output power.

The UE state in the connected mode defines the level of activity associated tothe UE. The key parameters of each state are the required activity and resourceswithin the state and the required signalling prior to the data transmission. The stateof the UE shall at least be dependent on the application requirement and the periodof inactivity.

Common Packet Channel (CPCH) uplink resources are available to UEs with anaccess protocol similar to the RACH. The CPCH resources support uplink packetcommunication for numerous UEs with a set of shared, contention-based CPCHchannels allocated to the cell.





Assuming that there exist an RRC connection; there are two basic families ofRRC connection mobility procedures, URA updating and handover. Different familiesof RRC connection mobility procedures are used in different levels of UE connection(cell level and URA level):

-URA updating is a family of procedures that updates the UTRAN registrationarea of a UE when an RRC connection exists and the position of the UE is known onURA level in the UTRAN;

-Handover is a family of procedures that adds or removes one or several radiolinks between one UE and UTRAN when an RRC connection exists and the positionof the UE is known on cell level in the UTRAN.

Connected Mode

Cell-DCH

In active state.

Communicating via its dedicated channels.

UTRAN knows which cell UE is in.

If there is huge data to be transmitted, it must allocate dedicated channel. ThusUE will be in Cell-DCH. UE in Cell-DCH state is communicating via DCH (downlinkand uplink) with UTRAN.

Cell-FACH In active state.

Few data to be transmitted both in uplink and in downlink. There is noneed to allocate dedicated channel for this UE.

Downlink uses FACH and uplink uses RACH.

UE need to monitor the FACH for its relative information.


If there is only few data to be transmitted,there is no need to allocate dedicatedchannel. Thus UE will be in Cell-FACH. UE in Cell-FACH state is communicating via

FACH (downlink) and RACH (uplink) with UTRAN. UE need to monitor the FACH forits relative information because FACH is shared for all users in the cell.





Cell-PCH

No data to be transmitted or received.

Monitor PICH, to receive its paging.

lower the power consumption of UE.


UTRAN have to update cell information of UE when UE roams toanother cell.

If UE has no data to be transmitted or received, UE will be in Cell-PCH or URA-PCH. In these two states, UE needs to monitor PICH,to receive its paging. UTRANknows which cell or URA UE is now in. The difference between Cell-PCH and URA-PCH is that UTRAN update UE information only after UE which is in URA-PCH statehas roamed to other URA.

UTRAN have to update cell information of UE when UE roams to another cell.UE migrates to cell-FACH state to complete the cell update. If there is also no data tobe transmitted or received, UE is back to CELL-PCH state after cell update. If thecell update times in a fixed time reach a preset value, UTRAN will let UE migrate toURA-PCH. URA is an area of several cells.

URA-PCH

No data to be transmitted or received.

Monitor PICH.

UTRAN only knows which URA (UTRAN Registration Area, which

consists of multiple cells) that UE is in. UTRAN updates UE information only after UE has roamed to other

URA.

A better way to reduce the resource occupancy and signalingtransmission.

It is the same as the CELL-PCH state. UE should migrate to CELL-FACH state tocomplete the URA update.





UE States

Figure 14. - User equipment states.

This is the UE states figure. These states are significant only for UTRAN and UE.They are transparent to CN.





RNTI - Radio Network Temporary Identifier

Five Types of RNTI exist

Serving RNC RNTI (S-RNTI).

Drift RNC RNTI (D-RNTI).

Cell RNTI (C-RNTI).

UTRAN RNTI (U-RNTI).

HS-DSCH RNTI (H-RNTI).

SRNTI

SRNTI is used by UE to identify itself to the serving RNC.

SRNTI is used by SRNC to address the UE.

SRNTI is used by DRNC to identify the UE to serving RNC.

SRNTI is allocated for all UEs having a RRC connection, it is allocated byserving RNC and it unique within the SRNC.SRNTI is always reallocated when theSRNC for the RRC connection is changed.

DRNTI

DRNTI is used to SRNC to identify the UE to the DRNC

DRNTI is never used on Uu interface. DRNTI is allocated by DRNC upon drift UEcontexts establishment and is unique within the DRNC. The SRNC knows themapping between SRNTI and DRNTI is allocated by DRNC for the same UE. TheDRNC shall know the SRNTI and SRNC ID related to existing DRNTI within the

DRNC.

CRNTI

CRNTI is used to by a UE to identify itself to the CRNC.

CRNTI is used to by CRNC to address the UE.

CRNTI is allocated by CRNC when UE accessing a new cell. CRNTI is uniquewithin the accessed cell.

URNTI

URNTI is consisted of SRNC identity and SRNTI.

HRNTI

HRNTI is allocated by CRNC when UE establishing a HS-DSCH channel. HRNTIshall be unique within the cell carrying the HS-DSCH.





3 UTRAN Signaling Procedure

3.1 Cell Setup

Figure 15. - Cell Setup signaling procedure.

Setup NCP and CCP in SAAL link stratum, which NCP carries the NBAP public

information and CCP carries the NBAP dedicated information. One NodeB only cansetup one NCP, but can setup several CCP.

To prepare the cell setting up, the resource of Node B should be audited.

Logic cell setup

Setup the common transport channel for cell, including RACH, FACH and PCH.





3.2 System Information Broadcast

System Information Broadcast Flow

Figure 16. - Signaling flow of System Information Broadcast.

Introduction of System Information

MIB：

Contains PLMN tag and SB (scheduling information block) or the schedulinginformation for SIB (system info block).

SB1：

Contains scheduling information for SIB.

SB2：

Contains scheduling information for SIB.

SIB1：

Contains the system information for NAS and the timer/counter for UE.

SIB2：

Contains the URA information.

SIB3：

Contains the parameters for cell selection and cell re-selection.





SIB4：

Contains parameters for cell selection and cell re-selection while UE is inconnecting mode.

SIB5：

Contains parameters for the common physical channels of the cell.

SIB6：

Contains parameters for the common physical channels of the cell while UE is inconnecting mode.

SIB7：

Contains the uplink interference level and the refreshing timer for SIB7.

SIB8：

Contains the CPCH static information.

SIB9：

Contains the CPCH dynamic information.

SIB10：

Contains information to be used by UEs having their DCH controlled by a DRACprocedure.

Used in FDD mode only.To be used in CELL_DCH state only.

Changes so often, its decoding is controlled by a timer.

SIB11：

Contains measurement controlling information.

SIB12：

Contains measurement controlling information in connecting mode.

SIB13：

Contains ANSI-41 system information.

SIB14:

Contains the information in TDD mode.





SIB15:

Contains the position service information.

SIB16:

Contains the needed pre-configuration information for handover from other RAT

to UTRAN.

SIB17:

Contains the configuration information for TDD.

SIB18:

Contains the PLMN identities of the neighboring cells.

To be used in shared networks to help with the cell reselection process.

System Information Block Type 1

Figure 17. - System Information Block Type 1.















System Information Block Type 7 and 11

System info type 7

Including the UL interference level which is used for open loop powercontrol.

Preamble_Initial_Power=Primary CPICH DL TX power - CPICH_RSCP+ UL interference + Constant Value.

Including the Expiration Time Factor which is used for refreshing theSIB7 periodically.

System info type 11

The neighbor cell information for cell re-selection in IDLE mode.





Paging

Paging Caused by CN

Figure 21. - Signaling flow for paging caused by CN.

The paging procedure is a procedure of paging initiated from the CN to the calledparty. When the CN needs to set up a connection with the called subscriber, it firstneeds to find the called subscriber via the paging procedure. The purpose of thepaging procedure is just to enable the CN to page the called subscriber. The pagingprocedure is set up via connectionless signaling.

The paging information type which is sent by UTRAN is decided by UE mode.

If UE is in the CELL_FACH or CELL_DCH ， UTRAN send paging type 2. Inother modes, the paging information is type 1 and UE can use DTX method to

detecting PICH.

When the RRC is idle, the UE may receive paging from the CS or PS domain.Because the UE is now in the idle state, the CN can learn the Location AreaIdentification (LAI) or RAI information of the UE. The paging will be sent via thislocation area and the LA or RA in this example crosses two RNCs.





The above example shows the paging procedure of the UE in the RRCconnected state (CELL_DCH or CELL_FACH), where the UTRAN coordinates thepaging request over the DCCH in the RRC connected state.

Paging Type 1 is sent over the PCCH when the UE is idle while Paging Type 2 issent over the DCCH when the UE is in the RRC connected state. The typical case isthat the UE uses the Paging Type 2 to send the PAGING message of the CS domainin the PS service procedure. However, the Paging Type is controlled by the RNC andthe CN does not need to know it.

Paging Caused by UTRAN

Figure 21.- Signaling flow for paging caused by CN.

Figure 22.- Signaling flow for paging caused by UTRAN.

When the system information is modified, UTRAN will send the paginginformation to tell UEs which are in IDLE, Cell_PCH or URA_PCH mode. Then, UEwill read the modified system information from BCH.

To change the state of UE which is in Cell_PCH or URA_PCH state, UTRAN willstart a paging flow. Then, UE will start a Cell-Update or URA update flow forresponse.





3.4 Call Process

Introduction of Call Process

In WCDMA system, a call process includes the following basic signaling flows:

RRC connection flow.

Iu interface signaling flow.

Authentication flow (optional).

Security flow (optional).

RAB establish flow.

Call proceeding.

NAS signaling before correlative bearer release.

Correlative bearer release.

RRC Connection Establishment Flow (DCH)

Figure 23- RRC Connection Establishment for Dedicated Channel.

In the idle mode, when the non-access layer of the UE requests to establish asignaling connection, the UE will initiate the RRC connection procedure. Each UEhas up to one RRC connection only.





Description:

1. The UE sends an RRC Connection Request message via the uplinkCCCH to request to establish an RRC connection.

2. Based on the RRC connection request cause and the system resourcestate, the SRNC decides to establish the connection on the dedicatedchannel, and allocates the RNTI and L1 and L2 resources.

3. The SRNC sends a Radio Link Setup Request message to Node B,requesting the Node B to allocate specific radio link resources requiredby the RRC connection.

4. After successfully preparing the resources, the Node B responds to theSRNC with the Radio Link Setup Response message.

5. The SRNC initiates the establishment of Iub user plane transportbearer with the ALCAP protocol and completes the synchronizationbetween the RNC and the Node B.

6. The SRNC sends an RRC Connection Setup message to the UE inthe downlink CCCH.

7. The UE sends an RRC Connection Setup Complete message to theSRNC in the uplink DCCH.

By now, the RRC connection setup procedure ends.





Iu Interface Signaling Connection Establish

Figure 24- Iu Interface Signaling Connection Establishment.

After the RRC connection between the UE and the UTRAN is successfully set up,the UE sets up a signaling connection with the CN via the RNC for NAS informationexchange between the UE and the CN, such as authentication, service request andconnection setup. This is also called the NAS signaling setup procedure.

For the RNC, the signaling exchanged between the UE and the CN is a directtransfer message. After receiving the first direct transfer message, that is, the InitialDirect Transfer message, the RNC sets up a signaling connection with the CN on theSCCP. The procedure is shown in the above figure:

The specific procedure is given as follows:

1. After the RRC connection is established, the UE sends the Initial DirectTransfer message to the RNC via the RRC connection. This messagecarries the NAS information content sent to the CN by the UE.

2. After receiving the Initial Direct Transfer message from the UE, theRNC sends the SCCP Connection Request (CR) message to the CNvia the Iu interface. The message content is the Initial UE Messagesent from the RNC to the CN, and carries the message content sentfrom the UE to the CN.





3. If the CN is ready to accept the connection request, then it returns theSCCP Connection Confirm (CC) message to the RNC. The SCCPconnection is successfully set up. The RNC receives the message andconfirms the signaling connection setup success.

4. If the CN cannot accept the connection request, then it returns theSCCP Connection Reject (CJ) message to the RNC. The SCCPconnection setup fails. The RNC receives the message and confirmsthe signaling connection setup failure. Then it initiates the RRC releaseprocedure.

After the signaling connection is successfully set up, the message sent by theUE to the CN is forwarded to the RNC via the Uplink Direct Transfer message, andthe RNC converts it into the Direct Transfer message to send to the CN. Themessage sent by the CN to the UE is forwarded to the RNC via the Direct Transfermessage, and the RNC converts it into the Downlink Direct Transfer to send to theUE.

Iu Interface Signaling Connection Establish

Figure 25- Signaling Connection Establishment for Iu Interface.

RNC. The SCCP connection is successfully set up. The RNC receives themessage and confirms the signaling connection setup success.





4. If the CN cannot accept the connection request, then it returns the SCCPConnection Reject (CJ) message to the RNC. The SCCP connection setup fails. TheRNC receives the message and confirms the signaling connection setup failure.Then it initiates the RRC release procedure.

After the signaling connection is successfully set up, the message sent by theUE to the CN is forwarded to the RNC via the Uplink Direct Transfer message, andthe RNC converts it into the Direct Transfer message to send to the CN. Themessage sent by the CN to the UE is forwarded to the RNC via the Direct Transfermessage, and the RNC converts it into the Downlink Direct Transfer to send to theUE.

Authentication and Security Flow

Figure 26- Authentication and security flow.

Authentication is used for the validity of CN and UE.

Security flow includes the encrypt process and integrity protection.





Common ID

Figure 27. - Common ID message.

RAB Establishment Flow

Figure 28. - Signaling flow for RAB Establishment.

RAB is the carrier which is provided by AS for NAS.

RAB is the carrier in user plane, which is for transferring the voice service, dataservice or multiple media service between UE and CN.





RAB establishment flow mainly includes the AAL2 PATH establishment of Iu andIub interface, also includes the reconfiguration process of radio resource.

The RAB refers to the user plane bearer that is used to transfer voice, data and

multimedia services between the UE and the CN. The UE needs to complete theRRC connection establishment before setting up the RAB.

The RAB setup is initiated by the CN and executed by the UTRAN. The basicprocedure is as follows:

1. First the CN sends the RAB assignment request message to theUTRAN, requesting the UTRAN to establish the RAB.

2. The SRNC in the UTRAN initiates the establishment of the data

transport bearer between the Iu interface and the Iub interface (Iurinterface).

3. The SRNC sends the RB setup request to the UE.

4. After completing the RB establishment, the UE responds to the SRNCwith the RB setup complete message.

5. The SRNC responds to the CN with the RAB assignment responsemessage and the RAB setup procedure ends.

When the RAB is successfully established, a basic call is set up and the UEenters the conversation process.





NAS Signaling (CS)

Figure 28.- Non Access Stratum Signaling for CS.

Authentication and security flow are optional.

CN does not need to the CM Service Response if the security mode is used.

NAS Signaling (PS)

Figure 29.- Non Access Stratum Signaling for PS.





Authentication and security flow are optional.

CN does not need to the CM Service Response if the security mode is used.

UE to UE (1)

Figure 30.- Signaling flow for UE to UE connection.

UE to UE (2)






UE to UE (3)


UE to UE (4)






UE to UE (5)


UE to UE (6)












3.5 Handover

Concepts about Soft Handover

Soft handover: the signals from different NodeBs are merged in RNC.

Softer handover: the signals from different cells, but from the same NodeB aremerged in NodeB.

Soft handover:

Selection combination in uplink.

Maximum combination in downlink.

Softer handover.

Maximum combination in uplink and downlink.

Soft Handover Flow

Figure 38. - Soft Handover flow.

There is no handover in this picture, only one radio links is connected with UE.

Node B

RNC

AirBridgeAirBridge

AirBridgeAirBridge

AirBridgeAirBridgeNode B

RNC

AirBridgeAirBridgeAirBridgeAirBridge



Core NetworkCore Network





Soft Handover Flow

Figure 39. - Softer Handover flow.

It is softer handover. During the handover, the cells in active set are belong toone NodeB. The NodeB uses the RAKE receiver to combine the data, and the UEalso combines the data in RAKE receiver.

Soft Handover Flow

Figure 40. - Soft Handover flow.

It is soft handover. During the handover, the cells in active set are belong to oneRNC, but different NodeBs. So the UE can combine the data in RAKE receiver. Butin uplink, the data are combined with selection combination in RNC.

Node B

RNC

AirBridgeAirBridge

AirBridgeAirBridge

AirBridgeAirBridgeNode B

RNC




Merged in NodeB


Merged in RNC

Node B

RNC

AirBridgeAirBridge

AirBridgeAirBridge

AirBridgeAirBridge

Merged in RNC

Node B

RNC









Soft Handover Flow (SRNC-DRNC)

Figure 41. - Soft Handover flow (Change of RNC).

It is soft handover. During the handover, the cells in active set are belong todifferent RNCs. So the UE can combine the data in RAKE receiver. But in uplink, thedata are combined with selection combination in SRNC.

Merged in SRNC

Node B

AirBridgeAirBridge

AirBridgeAirBridge

AirBridgeAirBridge

Serving RNC

Drift RNC


Merged in SRNC

Node B




Serving RNC

Drift RNC






Soft Handover Flow (SRNC Relocation)

Figure 42. - Softer Handover flow.

It is no handover. The SRNC has changed.

Soft Handover Flow（（（（Intra-RNC））））

Figure 43. - Soft Handover flow (Intra RNC).

During the soft handover, two radio links are connected with UE, and data ineach RL are same.

Node B




Serving RNC

RNC


Before Handover After Handover

SRNCSRNC

NodeBNodeBNodeBNodeB

SRNCSRNC


SRNCSRNC


During Handover

CNCN CN





Soft Handover Flow（

（（

（

Add Branch in RNC）

））

）

Figure 44. - Soft Handover flow (Add Branch in RNC)

In the WCDMA system, since the intra-frequency exists among neighboring cells,the UE can communicate with the network via multiple radio links, and can selectone with good signal quality by comparison when these radio links are merged, thusoptimizing the communication quality. The soft handover can be conducted only inthe FDD mode. The soft handover falls into the following cases according to thelocations of the cells. The first case is the soft handover among difference cells of the

Node B. In this case, the radio links can be merged within the Node B or the SRNC.If they are merged within the Node B, it is called softer handover. The second case isthe soft handover among different Node Bs within the same RNC and amongdifferent RNCs.

An important issue during the soft handover is the merge of multiple radio links.In the WCDMA system, the MACRO DIVERSITY technology is adopted for themerge of the radio links, that is, the system compares the data from different radiolinks based on certain standards (such as BER), and selects the data with betterquality to send to the upper layer.

The following are some key concepts about the neighboring cell in the softhandover:

1. Active set : The set of cells currently used by the UE. The executionresult of the soft handover indicates the increase or decrease of thecells in the active set.

Decision to setup

new RL

7. DCCH : Active Set Update Complete

6.DCCH: Active Set Update

UE Node B(new) SRNC

NBAP1. Radio Link Setup RequestNBAP

NBAP2. Radio Link Setup ResponseNBAP

3 ALCAP Iub Data Transport Bearer Setup

Start RX description

DCH-FP4. Downlink SynchronisationDCH-FP

DCH-FP5.Uplink SynchronisationDCH-FP


RRC

RRC

RRC

RRC

Decision to setup

new RL



UE Node B(new) SRNC








RRC

RRC

RRC

RRC






（（

（

Add Branch in RNC）

））

）

Figure 45. - Soft Handover flow (Add Branch in RNC)

2. Monitor set : The set of cells that are not in the active set but are beingobserved by the UE based on the neighboring cell information from theUTRAN. The UE measures the cells in the observation set. When themeasurement results satisfy certain conditions, the cells may be addedto the active set. Therefore, the observation set sometimes is alsocalled the candidate set.

3. Detected set: The set of cells that have been detected by the UE butdo not belong to the active set or the observation set. The UTRAN canrequest the UE to report the measurement result of the detected set.Since the cells in the detected set are not listed in the neighboring celllist, this set is also called the unlisted set.

The soft handover procedure comprises the following steps:

1. Based on the measurement control information from the RNC, the UE

measures the intra-frequency neighboring cells, and reports themeasurement result to the RNC after processing.

2. The RNC compares the reported measurement result with the setthreshold to decide the cells to be added and deleted.

3. If some cells are to be added, the RNC notifies the Node B to get ready.

Decision to setup

new RL



UE Node B(new) SRNC








RRC

RRC

RRC

RRC

Decision to setup

new RL



UE Node B(new) SRNC








RRC

RRC

RRC

RRC





4. The RNC notifies the UE to add and/or delete cells via the active setupdate message.

5. After the UE successfully update the active set, if the cells are deleted,

the Node B will be notified to release the corresponding resources.

The original communication is not affected during the soft handover procedureso that smooth handover from a cell to another can be successfully completed.


（（

（

Del Branch in RNC）

））

）

Figure 46. - Soft Handover flow (Delete Branch in RNC)

Decision to deletea RL



UE Node B(old) SRNC

NBAP3. Radio Link Deletion RequestNBAP

NBAP4. Radio Link Deletion ResponseNBAP

RRC

RRC

RRC

RRC

Stop RX and Tx

5 ALCAP Iub Transport Bearer release

Decision to deletea RL



UE Node B(old) SRNC

NBAP3. Radio Link Deletion RequestNBAP

NBAP4. Radio Link Deletion ResponseNBAP

RRC

RRC

RRC

RRC

Stop RX and Tx

5 ALCAP Iub Transport Bearer release







Description:

1. The SRNC sends the Radio Link Setup Request message to the Node Bwhere the target cell is, requesting the Node B to establish a radio link.

2. The Node B where the target cell is sends the Radio Link Setup Response

message to the SRNC, indicating the radio link is successfully established.

3. The SRNC adopts the ALCAP protocol to set up the Iub interface transportbearer between the SRNC and the target Node B, and synchronizes the FP.

4. The SRNC sends the Physical Channel Reconfiguration message carrying thetarget cell information to the UE via the downlink DCCH.

5. After the UE hands over from the source cell to the target cell, the Node B ofthe source cell detects the radio link communication failure and then sends the

Radio Link Failure Indication message to the SRNC, indicating the radio linkfailure.

6. After successfully handing over to the target cell, the UE sends the PhysicalChannel Reconfiguration Complete message to the SRNC via the DCCH,notifying the SRNC that the physical cannel reconfiguration is complete.

Hard Handover (Intra-RNC)

Figure 49. - Signaling flow for Hard Handover (Intra-RNC).

UE Node B Source Node B Target SRNC

8. DCCH : Physical Channel Reconfiguration Complete

6.DCCH : Physical Channel Reconfiguration

1. Radio Link Setup Request

2. Radio Link Setup Response

9. Radio Link Deletion Request

10. Radio Link Deletion Response

3 ALCAP ub Data Transport Bearer Setup

7. Radio Link Failure IndicationRRCRRC

NBAPNBAP

NBAP

RRCRRC

NBAP

NBAP

NBAP NBAP

Decide to

handover

Start Rx

Start Tx



NBAP

NBAP

NBAP

11. ALCAP Iub Data Transport Bearer Release

UEUE Node BNode B Source Node BNode B Target SRNCSRNC

8. DCCH : Physical Channel Reconfiguration Complete

6.DCCH : Physical Channel Reconfiguration

1. Radio Link Setup Request

2. Radio Link Setup Response

9. Radio Link Deletion Request

10. Radio Link Deletion Response

3 ALCAP ub Data Transport Bearer Setup3 ALCAP ub Data Transport Bearer Setup

7. Radio Link Failure IndicationRRCRRC

NBAPNBAP

NBAP

RRCRRC

NBAP

NBAP

NBAP NBAP

Decide to

handover

Start Rx

Start Tx



NBAP

NBAP

NBAP

11. ALCAP Iub Data Transport Bearer Release11. ALCAP Iub Data Transport Bearer Release





7. The SRNC sends the Radio Link Deletion Request message to the Node Bwhere the source cell is, requesting the Node B to delete the radio link of thesource cell.

8. The Node B where the source cell is deletes the radio link resources, and thenresponds to the SRNC with the Radio Link Deletion Response message.

9. The SRNC adopts the ALCAP protocol to release the Iub interface transportbearer of the SRNC and the Node B where the source cell is.

SRNC Relocation

Figure 50. - Serving SRNC Relocation.

The RNC relocation refers to that the SRNC of the UE changes from one RNC toanother RNC. It is divided into two cases based on the UE location at the time ofrelocation: Static relocation and associated relocation, or in other words, UE NotInvolved and UE Involved.

The precondition for the static relocation is that the UE accesses the networkfrom one and only one DRNC. Since the relocation procedure does not require theUE’s participation, it is also called the UE Not Involved relocation. The following is anexample of two radio links. After the relocation, the original DRNC becomes theSRNC, the Iur interface connection is released, and the Iu interface migrates

Associated relocation refers to that the UE accesses the target RNC from theSRNC via hard handover, and the Iu interface changes at the same time. Since therelocation procedure requires the UE’s participation, it is also called the UE Involvedrelocation.

SRNS

Core Network

Iu

DRNSIur

UE

RNS

Core Network

Iu

SRNS

UE

After SRNS RelocationBefore SRNS Relocation

Cells





Hard Handover with Relocation (CS)

Figure 51. - Signaling flow for Hard Handover with Relocation (CS).

Associated relocation refers to that the UE accesses the target RNC from theSRNC via hard handover, and the Iu interface changes at the same time. Since therelocation procedure requires the UE’s participation, it is also called the UE Involvedrelocation.

Inter-System Handover Flow （

（（

（ UMTS->GSM ）

））

）

Figure 52. - Inter-System Handover Flow (UMTS-GSM).

SourceRNC TargetRNCCN

Relocation Reqired

R e l o c R e q

RANAP RANAP

RANAP RANAP

RANAP RANAPR e l o c R e q A c k

RANAP RANAPR e l o c a t i o n C m d

RANAP

RANAPI U R e l C o m p l e t e

RNSAP RNSAPR e l o c D e t e c t

UE

RRCP h y s i c a l C h a n n e l R e c f g R e q

NodeB

RNSAP RNSAPR L R e s t o r e I n d

RRC

RRCRRC P h y s i c a l C h a n n e l R e c f g C o m p l e t e

NodeB

RANAP RANAPR L D e l R e q

RANAP RANAPR L D e l R s p

RANAP

RANAP I U R e l C m d

R L S e t u p R e q

NBAP NBAP

NBAP NBAPR L S e t u p R s p

E s t R e q

E s t C o n f

D L S y n c

U L S y n c

Q.AAL2

Q.AAL2

Q.AAL2

Q.AAL2

DCH-FP

DCH-FP

DCH-FP

DCH-FP

U E N o d e B R N C 3 G M S C 2 G M S C B S S

M e a s u r e m e n t R e p o r t ( 2 D )

R L R e c f g P r e p

R L R e c f g R e a d y

P h y s i c a l C h a n n e l R e c o n f i g u r a t i o n

R L R e c f g C o m m i t

P h y s i c a l C h a n n e l R e c o n f i g u r a t i o n c m p

M e a s u r e m e n t C o n t r o l ( I n t e r R A T )

M e a s u r e m e n t R e p o r t ( G S M )

R e l o c a t i o n R e q u i r e d

R e l o c a t i o n C o m m a n d

P r e p a r e H a n d o v e r

H a n d o v e r R e q u e s t

H a n d o v e r R e q u e s t A C K

P r e p a r e H a n d o v e r R S P

H a n d o v e r F r o m U T R A N C M D

H a n d o v e r C o m p l e t e

I U r e l e a s e c o m m a n d

I U r e l e a s e c o m p l e t e

R R C C o n R e l e a s e R e q

R R C C o n R e l e a s e C m p

R L D e l R e q

R L D e l R s p





Inter-System Handover Flow (GSM-UMTS)

Figure 53. - Inter-System Handover Flow (GSM-UMTS).

Forward Handover

Forward Handover is sponsored by UE, including cell update and URA update.URA update is only used to make the URA re-selection for the UE which is inURA_PCH state, and check the RRC connection.

When UE is in Cell_FACH or Cell_PCH state

1. Cell reselection.

2. In service area, the T304 timer is overdue.

When UE is in Cell_PCH or URA_PCH state:

1. UE is going to upload data (from Cell_PCH or URA_PCH toCell_FACH).

2. After UE received the paging information from PCCH, UE sponsored

cell update.

U E N o d e B R N C 3 G M S C 2 G M S C B S S

R L s e t u p r e q u e s e t

R L s e t u p r e s p o n s e

R L R e s t o r e I n d i c a t o n

H a n d o v e r C o m p l e t e

U T R A N C a p a c i t y I n f o

U E C a p a c i t y I n f o E n q u i r y

R e l o c a t i o n R e q u e s e t

P r e p a r e H a n d o v e r

H a n d o v e r R e q u e s t

H a n d o v e r C o m m a n d

S e n d e n d s i g n a l

r e q u e s e t

I n t e r S y s t e m t o U T R A N H o c m d ( H a n d o v e r t o U T R A N C o m m a n d )

C l e a r c o m m a n d

C l e a r c o m p l e t e

U T R A N C a p a c i t y I n f o C o n f i r m

U E C a p a c i t y I n f o C o n f i r m

R e l o c a t i o n R e q u e s e t

A C K

P r e p a r e H a n d o v e r R S P

R e l o c a t i o n C o m p l e t e

S e n d e n d s i g n a l

r e s p o n s e

U E C a p a c i t y I n f o








Documents

009 WCDMA UTRAN Interface and Signaling Procedure