148521323 ZTE UMTS DRBC Algorithm Feature Guide V6!1!201204

DRBC Algorithm Feature

Guide

WCDMA RAN

DRBC Algorithm Feature Guide

ZTE Confidential Proprietary 1


Version Date Author Reviewer Notes

V6.0 2011-6-16 Wang

ChengWei

(1) Add parameter DchSig68Swch in

chapter 3.1.2.1;

(2) Add parameter DlPsRateLmtLowC,

UlPsRateLmtLowC, DlPsRateLmtHighC,

UlPsRateLmtHighC in chapter 3.1.3.1 and

3.1.3.3;

(3) Add chapter 3.5 Enhanced FACH

Dynamic Channel Adjustment.

(4) Add chapter 3.7.6 Switching timers

based on UE capabilities;

(5) Update some parameters OMCR path.

(6) Add the related description for CResPara4

in chapter 3.7.3 IUB transmission bandwidth

limitation strategy.

V6.1 2012-2-28

Wang

ChengWei,

Sha Xiubin

Jiang Qingsong

The following section and related parameters

added:

3.7.7 CS Experience Improvement

for Concurrence Service with CS+PS

3.7.8 UE PCH Compatibility

Strategy

3.7.9 DRBC F/P->D Performance

Optimization

3.7.10 CELL_PCH Supporting

2012 ZTE Corporation. All rights reserved.

ZTE CONFIDENTIAL: This document contains proprietary information of ZTE and is not to be disclosed or used

without the prior written permission of ZTE.

Due to update and improvement of ZTE products and technologies, information in this document is subjected to

change without notice.



TABLE OF CONTENTS

1 Function Attribute ................................................................................................. 5

2 Introduction............................................................................................................ 5

2.1 Function Introduction ............................................................................................... 5

2.2 Dynamic Channel Type Transfer for R99 Service................................................... 7

2.3 Dynamic Channel Type Transfer for HSDPA Service............................................. 9

2.4 Dynamic Channel Type Transfer for HSUPA Service........................................... 10

2.5 RAB Negotiation & Re-negotiation ........................................................................ 11

2.6 27.2Kbps High Speed Signaling RB...................................................................... 12

2.7 Fast Dormancy ....................................................................................................... 12

3 Technical Description ......................................................................................... 12

3.1 Dynamic Channel Type Transfer for R99 Service................................................. 12

3.1.1 Introduction to Service Types ................................................................................ 12

3.1.2 Initial Channel Allocation ....................................................................................... 13

3.1.3 Channel Switching ................................................................................................. 19

3.1.4 Related Measurement............................................................................................ 38

3.2 Dynamic Channel Type Transfer for HSDPA Service........................................... 47

3.2.1 Signaling Channel Allocation ................................................................................. 47

3.2.2 Initial Service Channel Allocation .......................................................................... 48



3.3 Dynamic Channel Type Transfer for HSUPA Service........................................... 59

3.3.1 Signaling Channel Allocation ................................................................................. 59




3.4 Dual-Carrier related Dynamic Channel Adjustment .............................................. 74


3.4.2 Concurrent Service Channel Allocation................................................................. 74


3.5 Enhanced FACH Dynamic Channel Adjustment ................................................... 75

3.5.1 DL Enhanced FACH Dynamic Channel Adjustment ............................................. 75

3.5.2 UL Enhanced FACH Dynamic Channel Adjustment ............................................. 78

3.5.3 Traffic Measurement .............................................................................................. 80

3.6 Fast Dormancy ....................................................................................................... 81



3.6.1 R8 Fast Dormancy ................................................................................................. 81

3.6.2 Pre-R7 Fast Dormancy Suppressing..................................................................... 82

3.7 Other Description ................................................................................................... 84

3.7.1 Traffic Sub-class rate matching ............................................................................. 84

3.7.2 MBR Controlling in RNC ........................................................................................ 87

3.7.3 IUB transmission bandwidth limitation strategy..................................................... 88

3.7.4 Be compatible with the IPHONE which is not implement according to encryption

protocol................................................................................................................... 88

3.7.5 The MaxBR of HSDPA on Iur interface ................................................................. 89

3.7.6 Switching Timers Based on UE Capabilities ......................................................... 89

3.7.7 CS Experience Improvement for Concurrence Service with CS+PS ................... 91

3.7.8 UE PCH Compatibility Strategy ............................................................................. 92

3.7.9 DRBC F/P->D Performance Optimization ............................................................. 92

3.7.10 CELL_PCH Supporting .......................................................................................... 93

4 Configuration of Parameters.............................................................................. 94

4.1 DRBC Related Parameters.................................................................................... 94

4.1.1 Parameter List ........................................................................................................ 94

4.1.2 Parameter Configuration........................................................................................ 98

4.2 HSDPA Dynamic Channel Adjustment Related Parameters .............................. 126

4.2.1 Parameter List ...................................................................................................... 126

4.2.2 Parameter Configuration...................................................................................... 126

4.3 HSUPA Dynamic Channel Adjustment Related Parameters .............................. 130

4.3.1 Parameter List ...................................................................................................... 130


4.4 HSPA+ Dynamic Channel Adjustment Parameters ............................................ 134

4.4.1 Parameter List ...................................................................................................... 134


4.5 UE Traffic Volume Measurement Related Parameters ....................................... 135

4.5.1 Parameter List ...................................................................................................... 135


4.6 UE Internal TxP Measurement Related Parameters ................................... 156

4.6.1 Parameter List ...................................................................................................... 156

4.7 Node B Dedicated TCP Measurement Related Parameters ...................... 161

4.7.1 Parameter List ...................................................................................................... 161

5 Counter And Alarm ............................................................................................ 163

5.1 Counter List .......................................................................................................... 163

5.2 Alarm List ............................................................................................................. 168

6 Glossary ............................................................................................................. 168



FIGURES

Figure 2-1 State Transitions .................................................................................................... 6

Figure 3-1 R99 Channel Switching ....................................................................................... 19

Figure 3-2 Event Triggering of Traffic Measurement ............................................................ 39

Figure 3-3 Rate Adjustment Triggered by Traffic.................................................................. 41

Figure 3-4 HSDPA Channel Switching ................................................................................. 51

Figure 3-5 Event 1E in Channel Quality Measurement ........................................................ 57

Figure 3-6 Event 1F in Channel Quality Measurement ........................................................ 57

Figure 3-7 HSUPA Channel Switching ................................................................................. 64



1 Function Attribute

System version: [RNC V3.11.10/V4.11.10, OMMR V3.11.10/V4.11.10, Node B V4.11.10,

OMMB V4.11.10]

Attribute: [Optional]

Related NEs:

UE NodeB RNC MSCS MGW SGSN GGSN HLR

- - - - -

Note:

*-: Non-related NE:

*: Related NE

Dependency: [None]

Exclusion: [None]

Remarks: [None]

2 Introduction

2.1 Function Introduction

The dynamic radio bearer control (DRBC) is to allocate resources reasonably according

to subscriber requirements and system resource utilization to make full use of the

bandwidth. ZTE RAN DRBC policies mainly include the following functions:

Initial Channel Allocation

During channel setup, the DRBC allocates proper channel and rate for the service

according to service requirements and system resource utilization status. Including:



Signaling Channel Allocation

Initial Service Channel Allocation

Concurrent Service Channel Allocation

Initial Access Rate Allocation for DCH

Channel Switching

The DRBC selects appropriate transport channels according to the actual rate of PS

services. If the PS rate changes, the channel type also changes. The system monitors

the actual rate of PS services. If the actual data flow is smaller than the allocated

bandwidth, the system decreases the configured bandwidth to save resources. When the

actual data flow is close to the allocated bandwidth, the system increases the configured

bandwidth to prevent the service from being affected.

During the session, the DRBC adjusts the service bandwidth and channel switching in

real-time according to various measurements. The conversation service uses DL

DCH/UL DCH, streaming services use CELL_DCH, and interactive and background

services use CELL_FACH or CELL_DCH. The figure of state transitions currently

supported by system is as follows:

Figure 2-1 State Transitions

Connected Mode

Idle Mode

CELL_DCH

CELL_FACH

URA_PCH

PCH

DL FACH/ UL RACH

DL HS-DSCH/ UL DCH DL DCH/UL DCH

DL HS-DSCH/ UL E-DCH DL DCH/ UL

DCH

DL DCH/ UL DCH -> DL DCH/UL DCH

UL/DL Decrease or Increase Rate

Notes:



CELL_DCH service uses channels of the following types: DL HS-DSCH/UL E-DCH,

DL HS-DSCH/UL DCH, and DL DCH/UL DCH. RAN will determine different channel

types for services based on different support capabilities of NodeB and UE, and

service features. Switching could be performed between different channel types.

And the rates of DL DCH and UL DCH can be adjusted dynamically.

CELL_FACH service can use DL FACH/UL RACH.

Except that it does not support the switching from URA_PCH to CELL_DCH directly,

the channels in URA_PCH, CELL_FACH, and CELL_DCH states can be switched

among each other.

2.2 Dynamic Channel Type Transfer for R99 Service

R99 DRBC dynamically adjusts the bearer channel and real-time rate of PS services. It

ensures full utilization of radio resources , system stability, and service QoS .

During channel setup, the DRBC allocates radio channel and initial rate to the

service according to service requirements and system resource utilization status.

CS service and Streaming service can use DCH as bearer. The DCH channel

parameters are set according to necessary GBR.

Interactive service and Background Service may use FACH/RACH or DCH.

For PS services that use DCH as bearer, its initial access rate can b e set

according to configuration.

Dynamical DCH rate adjustment.

DCH rate configuration should be consistent with actual traffic rate. When

actual traffic volume drops, DCH rate should be decreased accordingly.

Released resource can be used by other us ers. DCH rate can be increased

when actual traffic volume gets high so as to avoid affecting user experience .

The traffic volume is evaluated in uplink and downlink separately. That is,

uplink traffic volume decides uplink DCH bandwidth while downlink bandwidth

depends on downlink traffic volume. In reality, it is common that the DCH

bandwidth should be adjusted simultaneously in uplink and downlink. In this



case, ZTE RAN adjusts the DCH bandwidth in uplink and downlink via a single

signalling procedure so that the signalling message on Uu is reduced.

DCH rate downgrade is an alternative method to decrease the system load

when overload or congestion occurs.

If the transmission power exceeds the preset high threshold, the network and

UE will decrease the data rate till the transmission power is lower than the

preset low threshold. By this method, PS service subscribers obtain relatively

high data rate when Node B is close, and obtain lower data rate when the

Node B is remote. Thus, the coverage of PS services is expanded. The call

drop rate of high-rate services during handovers is also decreased.

When UE performs a hard handover from one R99 cell to another due to

mobility, if the subscriber downlink admission at the current rate fails in the

target cell, the system will downgrade its DCH rate before retrying handover.

Channel switching:

If the practical rate of PS Interactive Service or PS Background Service below

the traffic volume threshold or if overload occurs in the cell, RAB can switch to

FACH/RACH from DCH and UE then enters the CELL FACH state.

If the practical rate exceeds the traffic volume threshold of FACH/RACH, RAB

will switch to DCH and UE then enter the CELL DCH state.

If the practical rate is zero, radio resource can be released temporarily. UE of

Cell FACH state or Cell DCH state can be switched to URA PCH state to save

UEs battery power. If it is configured not to use PCH state, RRC can be

released immediately.

When the UE in URA_PCH state originates the cell update message due to

uplink or downlink data transmission requirements or for new service setup,

the system allocates the channel by the UE service type before the UE is

handed over to PCH by the process of initial service channel allocation.

If a UE has resided in URA PCH state for period, the RRC will be released.

ZTE RAN system supports DRBC feature combined with other RRM policy including



Admission Control, Overload Control and Congestion Control . Priorities of users and

services are considered to implement dynamic optimization configuration of radio

bandwidth.

2.3 Dynamic Channel Type Transfer for HSDPA Service

After introducing HSDPA, ZTE RAN system is able to select bearer channel among

Hs-DSCH, DCH or FACH for the service and configure radio parameters correspondingly,

according to service requirement and system resource utilization status.

ZTE RAN equipments support dynamic channel switching between different channels in

order to satisfy services requirement and system resource in the following factor state:

Save system resource by adjusting channel type dynamically according to I/B

real-time traffic volume:

When downlink traffic volume is too large, trigger the channel switching from

FACH or DCH to HS-DSCH

When downlink traffic volume is too small, trigger the channel switching from

HS-DSCH to FACH

When there is no downlink traffic volume, trigger the channel switching from

HS-DSCH to PCH or idle

Reduce the system load by adjusting channel type according to cell load.

When cell load is too high, the user can switch from HS-DSCH to FACH to reduce

the system load and maintain the system stability.

Ensure service quality by adjusting channel type according to channel quality.

When UE in HS-DSCH channel moving to cell edge to trigger 1F event, it shows the

channel quality is bad, and then trigger the channel switching from HS-DSCH to

DCH.

Ensure the service continuity by adjusting channel type according to the target cell

for handover.



If the capability of source cell and target cell is different during hand over, the

channel switching between HS-DSCH and DCH will be triggered to guarantee the

service continuity.

Downlink channel switching accompanies uplink channel switching: When downlink

channel is FACH, uplink channel is RACH; when downlink channel is HS-DSCH, uplink

channel can be DCH or E-DCH.

2.4 Dynamic Channel Type Transfer for HSUPA Service

After introducing HSUPA, ZTE RAN system is able to select bearer channel among

E-DCH, DCH or RACH for the service and configure radio parameters correspondingly,

according to service requirement and system resource utilization status.

In order to accommodate requirements of service and practical status of system

resources, ZTE RAN system supports the following functions during channel switching:

Dynamically adjust channel type to save system resource according to the practical

traffic volume of I/B services:

If the traffic volume is high, the channel switching from RACH or DCH to

E-DCH will be triggered

If the traffic volume is low, the channel switching from E -DCH to RACH will be

triggered

If no traffic volume, the channel switching from E-DCH to PCH or Idle will be

triggered

Adjust channel type to decrease the system load according to cell load

When the cell uplink is overloaded, the user can be switched to common RACH

from dedicated E-DCH to decrease the system load and guarantee the system

stabilized.

Adjust channel type to guarantee the service quality according to channel quality

If a UE on E-DCH channel moves to the edge of the cell and triggers 1F eve nt, it



indicates that the quality of current channel is bad and the channel switching from

E-DCH to DCH will be triggered.

Adjust channel type to guarantee mobile service continuity according to the

capability of target cell

If the capability of source cell and target cell is different during handover, the

channel switching between E-DCH and DCH will be triggered to guarantee the

service continuity.

Uplink channel switching accompanies downlink channel switching: If uplink channel is

RACH, downlink channel is FACH. If uplink channel is E-DCH, generally, downlink

channel is HS-DSCH.

2.5 RAB Negotiation & Re-negotiation

When RAB setup or relocation, it can execute QoS negotiation, also when the calling

process, it can execute QoS negotiation. RNC can get alternative GBR information

through RAB ASSIGNMENT REQUES Tor RELOCATION REQUEST from CN, and take

this as the GBR level of this RAB. There are two situations of RAB QoS negotiation /

renegotiation: GBR increase and GBR decrease.

GBR increase is triggered by event 4A of traffic volume measurement reports: the traffic

measurement reports of uplink DCH is from UE; the traffic measurement reports of

downlink DCH, downlink HS-DSCH and uplink E-DCH is from user plane. The traffic

measurement adopts the traffic measurem ent control of DRBC, such as 4A threshold,

trigger time and pending time.

GBR decrease is triggered by cell common overload. When common overload appears,

the executions will be performed as follow: Decreasing the service rate of R99

subscribers, forcedly handing over to inter-frequency or inter-RAT neighboring cell,

deleting the radio link of any soft handover, decreasing GBR, forcedly releasing the

service. For more details of overload, see ZTE UMTS Overload Control Feature Guide )

For more details of RAB QoS negotiation / renegotiation, see ZTE UMTS Services and

Radio Access Bearers Feature Guide )



2.6 27.2Kbps High Speed Signaling RB

This feature enables the system to use the 27.2 kbps Signaling Radio Bearer (SRB)

when it establishes the RRC connection, and recovers the 3.4Kbps SRB after RAB is

established. If 27.2k SRB is set to apply on OMC, ZTE RAN will employ 27.2kbps SRB to

speed up t ransferring the NAS signaling messages (including location update message,

authentication message, and call setup message) between the UE and the CN.

Compared with 13.6kbps SRB, the 27.2 kbps SRB can reduce the call setup time delay

and shorten the SMS service reception. For detail of 27.2 kbps SRB ,please see the

chapter 3.1.2.1Signaling Channel Allocation.

2.7 Fast Dormancy

This feature includes two functions: R8 Fast dormancy and Pre -R7 Fast dormancy

suppressing. R8 Fast dormancy function can extend UE battery usage and improve user

experience. Pre-R7 Fast dormancy suppressing function can reduce the control plane

signaling load for smart phone on the premise that guaranteeing user experience. For

the detail, please see the chapter 3.5 Fast dormancy.

3 Technical Description

3.1 Dynamic Channel Type Transfer for R99 Service

3.1.1 Introduction to Service Types

Because different types of services have different features, the services have different

requirements for the occupied channel resources during channel allocation. Currently,

the services can be categorized into four types: Conversation, Interactive, Background,

and Streaming.

The conversation and streaming services are real-time services, and interactive and

background services are not real-time services.



3.1.2 Initial Channel Allocation

3.1.2.1 Signaling Channel Allocation

The OMC provides various parameter options so that the signaling rate can be flexibly

configured by the parameter InitRrcOnDch at different rates on different channels in the

case of RRC connection establishment.

When the parameter InitRrcOnDch is set to0 ,the RNC sets the initial signaling to

forcibly use DCH/DCH at 3.4k

When a UE sends a connection setup request to RNC, the RNC configures the

bidirectional 3.4 kbit/s DCH for the UE to bear signaling.






use common channel forcibly


uplink RACH or downlink FACH channel for the UE to bear signaling.


choose channel automatically, and setting DCH/DCH at 3.4k, when dedicated

channel is used

When a UE sends a connection setup request to RNC, the RNC automatically

select the dedicated channel (3.4 kbit/s) or common channel based on the reason

for connection setup: if services are initiated immediately after the setup of RRC

connection, RNC will select DCH channel and configures bidirectional 3.4 kbit/s

bear signaling; if there is only LA update, instead of setting up services, that should

be completed after RRC connection, RNC will select common channel to bear

signaling.





channel is used




connection, RNC will select DCH channel and configures bidirectional 13.6 kbit/s


be completed after RRC connection, RNC will select common channel to bear

signaling.







channel is used




connection, RNC will select DCH channel and reconfigures bidirectional 27.2 kbit/s


be completed after RRC connection, RNC will reconfigure common channel to bear

signaling.


forcibly use HSPA.

When a UE sends a connection setup request to RNC, if both the UE and the cell

support F-DPCH, both CresPara7 and RncFdpchSupInd are 1,(or both the UE

and the cell support E-FDPCH, both RncEfdpchSupInd and EfdpchSupInd are 1 ),

and both the UE and the cell support E-DCH,, and SrbOnEdchSwch is on, and the



channel quality measurement is not 1F event, the RNC configures the HSPA for the

UE to bear signaling.


choose channel automatically, and HSPA is prior, when Cell_DCH state is used


select the Cell_DCH state channel or Cell_FACH state channel based on the

reason for connection setup ,and HSPA is prior, when Cell_DCH state is used.

When the RNC sets the initial signaling to choose channel automatically, the signaling

will be set on Cell_DCH state bearer in preference if the signaling is set due to the

following reasons: Originating Conversational Call, Originating Streaming Call,

Originating Interactive Call, Originating Background Call, Originating Subscribed traffic

Call, Terminating Conversational Call, Terminating Streaming Call, Terminating

Interactive Call, Terminating Background Call, Emergency Call, Inter-RAT cell change

order, Call re-establishment, and MBMS ptp RB request; if the signaling is set due to

other reasons, it will be set on Cell_FACH state bearer.

High-rate (13.6 kbit/s,27.2kbps) signaling bearer only exits in a separate signaling

process, and will be restored to ordinary rate (3.4 kbit/s) after the service is set up.

High-rate signaling can effectively speed up the signaling interaction during the UE call

setup and lower the call delay, but it occupies more radio resources than ordinary rate

signaling bearer. Using common channel for signaling bearer does not occupy the

dedicated resources. Considering that the separate signaling process is short, and the

radio connection is released or services are set up after the signaling interaction, the

configuration of high rate signaling is recommended.

Note: During RRC connection setup when signaling is carried on DCH , or when RAB has been

setup and signaling is carried on DPCH alone , and if signaling is setup with DCH low rate:

If DchSig68Swch is on, it will substitute 3.4kbps signaling with 6.8 kbps signaling; Otherwise, If

DchSig68Swch is off, 3.4kbps signaling is used.

3.1.2.2 Initial Service Channel Allocation

For a RAB request of a service, the RNC chooses the initial channel for the service by

the service features (RAB parameters). Selection principles:



The conversation and streaming services use DL DCH/UL DCH.

The interactive and background services can use DL DCH/UL DCH and DL

FACH/UL RACH.

Whether the DL DCH/UL DCH or DL FACH/UL RACH is used for interactive and

background services depends on the values of MaxBR in RAB allocation and Rfach and

Rrach. If DL MaxBR is greater than or equal to Rfach, or UL MaxBR is greater than or

equal to Rrach, the DL DCH/UL DCH is chosen in preference. Otherwise, the DL

FACH/UL RACH is chosen in preference. If FACH/RACH is rejected to access, the RNC

will reselect the DL DCH/UL DCH to access.

3.1.2.3 Concurrent Service Channel Allocation

The concurrent service means the setup of new service when a UE already has an online

call service.

If a subscriber is in the CELL_DCH state, the new service is also set up on the DCH

channel. The initial rate of the new service is determined by the same method as

that for a single service.

If the subscriber is in the CELL_FACH state, the system judges whether to perform

state transitions according to the new service type.

If the new service should be set up on the DL DCH/UL DCH channel according

to the channel allocation principles as for a single service, the UE should

switch from CELL_FACH state to CELL_DCH state, that is, all the online

services will be switched to DCH channel. The initial rate of the new service is

determined by the same method as that for a single service.

If the new service is set up on the DL FACH/UL RACH channel according to

the channel allocation principles as for a single service, the UE keeps in the

CELL_FACH state, without impact on the online services.

For concurrent CS and PS (S/I/B) services:

If the DRBC switch DrbcSwch is set to OFF, the DCH rate of PS (S/I/B) services is

the minimum DRBC rate (max (highest rate level of DRBC, GBR), MaxBR). The



uplink and downlink DRBC rate levels are configured by

UlRateAdjLev[MAX_NUM_RATE_ADJUST] and

DlRateAdjLev[MAX_NUM_RATE_ADJUST] separately.

If the DRBC switch DrbcSwch is ON, the DCH rate of PS (S/I/B) services is the

minimum DRBC rate of DCH (see 3.1.2.5). Rate increase is allowed based on rate

increase principles (see UL DCH -> UL DCH (rate increase) and DL DCH -> DL

DCH (rate increase)). The uplink and downlink DRBC rate levels are configured by


DlRateAdjLev[MAX_NUM_RATE_ADJUST] separately.

Where, the GBR of streaming services is the GBR of RAB allocation; the GBR of I/B

services is 0; the MaxBR is the maximum bit rate of RAB allocation by Iu interface.

3.1.2.4 The Access Strategy of CS64K Service

According to some special scenarios where CS64K service is not expected to

access/handover in a cell, parameters Cs64kSwitch and AdjCs64Switch are used to

control whether cells support CS64k service in SRNC and DRNC, respectively. When

CS64k service is restricted in a cell, ingoing and handover of CS64k service are

forbidden.

Initial access scene: if the switch Cs64Switch in the cell is off ,CS 64k service is not

allowed to access; otherwise CS 64k service is allowed. For the UE in macro

diversity, if any cell of the active set is not allowed to access CS 64k service, it is not

allowed.

Handover scene: When handover happens in intra-RNC cells and CS64k service is

covered, if Cs64kSwitch in target cell is off and UE supports CS64k falling back to

AMR12.2k, then CS64k falls back to AMR12.2k and UE performs the related

disposal about handover, otherwise UE doesnt perform any disposal. When

handover happens in inter-RNC cells and CS64k service is covered, if

AdjCs64kSwitch in target cell is off and UE supports CS64k falling back to

AMR12.2k, then CS64k falls back to AMR12.2k and UE performs the related

disposal about handover, otherwise UE doesnt perform any disposal. If the

configuration in DRNC cell and SRNC cell is not given, the cell is defaulted to



support CS64k.

3.1.2.5 DCH Initial Access Rate for PS Service

The initial access rate of DL DCH/UL DCH of PS services is determined in the following

way:

If the DRBC switch DrbcSwch is set to OFF, the DCH initial rate is min(max (the highest

rate level of DBRC, GBR), MaxBR). The uplink and downlink DRBC rate levels are

configured by UlRateAdjLev[MAX_NUM_RATE_ADJUST] and

DlRateAdjLev[MAX_NUM_RATE_ADJUST] separately,the MaxBR is the maximum bit

rate of RAB allocation by Iu interface.

If the DRBC switch DrbcSwch is ON, the DCH initial rate is min(max (Initial Access Rate

for DCH, GBR), MaxBR, DCH Limited Rate). Here, the uplink and downlink Initial

Access Rate for DCH is configured by parameter InitialRateUl and InitialRateDl

separately, If the admission decision for the DCH initial rate is failed, UL and DL DCH will

try to access with the minimum DRBC rate of DCH at the same time, which is defined as

min( max(the lowest rate level of DBRC, GBR), MaxBR, DCH Limited Rate) .

Here, for the DCH Limited Rate:

In the case of intra-RNC, parameters RtMaxUlRateDch / RtMaxDlRateDch (for RT

service) and NrtMaxUlRateDch / NrtMaxDlRateDch (for NRT service) are used to limited

the DCH maximum rate of uplink and downlink respectively.

In the case of inter-RNC, parameters RtMaxUlRateDchD / RtMaxDlRateDchD (for RT

service) and NrtMaxUlRateDchD / NrtMaxDlRateDchD (for NRT service) are used to

limited the DCH maximum rate of uplink and downlink respectively. If the related

parameters are not configured in the neighboring cells, the restriction decision does not

effect.

In the case of macro diversity, the DCH Limited Rate is set to the minimum limited rate

value of all the cells in the active set.



3.1.3 Channel Switching

The channel switching and dynamic resource adjustments are performed only when the

DRBC switch (DrbcSwch) is ON.

During the session, the dynamic channel switching for the R99 system is to adjust the

service bandwidth and hand over channels in real-time according to the measurements

of traffic, cell load, DL DTCP, and UL UE Txp. The figure below shows the R99 channel

switching that the system currently supports according to the R99 protocol.

Figure 3-1 R99 Channel Switching

CELL_DCH

DCH/DCH

CELL_FACH

FACH/RACH

URA_PCH

PCH

Idle

Reconfig SF

1. UL/DL Traffic Volume

Based

2. DL D-TCP Based

3. UL TxP Based

4. Cells RTWP5. Cells TCP

Transition of DCH/DCH -> FACH/RACH

1. UL&DL Traffic Volume Based

2. Support CELL_FACH

Transition of FACH/RACH -> DCH/DCH

1. UL/DL Traffic Volume Based

2. Cells RTWP & Cells TCP

Transition of DCH/DCH -> PCH


2. Support PCH

Transition of FACH/RACH -> IDLE


Transition of DCH/DCH ->IDLE


Transition of PCH->IDLE

1. DL&UL Traffic Volume Based

Transition of FACH/RACH -> PCH


2. Support PCH

Transition of PCH -> FACH/RACH

1. UL/DL Traffic Volume based

Below we will introduce the switching principles for types of channel switching shown in

the above figure.

3.1.3.1 DL DCH -> DL DCH (Rate Increase)

Rate increase triggered by downlink traffic

The DCH to DCH rate increase is based on the traffic measurement report (Event 4A)

from the user plane and determined by the dedicated transmission power of the

subscriber and cell load.

The 4A event is defined as the t raffic measurement larger than an absolute threshold.

See 3.1.4.1Traffic Measurement for its detailed definition.



The Event A is defined as that the Node B downlink dedicated transmission power

(D-TCP) is greater than an absolute threshold. The Event B is defined as that the Node B

downlink dedicated transmission power (D-TCP) s smaller than an absolute threshold.

See 3.1.4.3Node B Dedicated TCP Measurement for detailed definitions.

The downlink DCH rate increase is triggered in the case of the following conditions:

The DCH rate adjustment triggered by traffic switch DchAdjRateSwch is on.

The system receives consecutive DchE4aThd traffic measurement reports (Event

4A) from the user plane. (Note: i f the system receives a traffic measurement report

(Event 4B) from the user plane when the receiving times are smaller than the

threshold, the corresponding counter is cleared)

The system receives consecutive DtcpEbThd measurement reports (Event B) of

NodeB D-TCP, that is, the UE is in B state. (Note: if the system receives a

measurement report (Event A) of NodeB when the receiving time is smaller than the

threshold, the corresponding counter is cleared.)

The downlink load of the cell is not overloaded (the downlink load is determined by

TCP. For details of overload threshold, see ZTE UMTS Overload Control Feature

Guide)

For non-macro diversity, in the case of DCH rate increase:

The target rate of NRT DCH is min (next rate level greater than the current rate in the

DRBC downlink rate levels DlRateAdjLev[MAX_NUM_RATE_ADJUST] , DCH Limited

Rate, DL MaxBR). The MaxBR is the maximum bit rate during RAB allocation.

The target rate of RT DCH is min (next rate level greater than the current rate in the

DRBC downlink rate levels DlRateAdjLev[MAX_NUM_RATE_ADJUST] , DCH Limited

Rate, DL MaxBR).

For macro diversity, in the case of DCH rate increase:

The target rate of NRT Downlink DCH rate is min (next rate level greater than the current

rate in DRBC downlink rate levels DlRateAdjLev[MAX_NUM_RATE_ADJUST], DL

MaxBR, DCH Limited Rate, MaxRateMD).



The target rate of RT Downlink DCH rate is min (next rate level greater than the current

rate in DRBC downlink rate levels DlRateAdjLev[MAX_NUM_RATE_ADJUST], DL

MaxBR, the minimum DCH Limited Rate , MaxRateMD).

Here, for the DCH Limited Rate explanation, please see 3.1.2.5; The MaxRateMD is

the maximum rate threshold allowed for DCH when the UE is in macro diversity.

In addition, in case of the concurrence of C (CS) services and PS (S/I/B) services, the

additional principles of rate increase of PS services are as follows:

Determine the maximum rate threshold of NRT PS (I/B) services by distinguish the

rates of C (CS) services themselves

If the rate of C (CS) services is less than or equal to CRateThrd, the sum of

downlink rates of concurrent PS services of NRT can not exceed

DlPsRateLmtLowC

If the rate of C (CS) services exceeds CRateThrd, the sum of downlink rates of

concurrent PS services of NRT can not exceed DlPsRateLmtHighC

The rate of streaming services is not restricted by the above rate threshold.

3.1.3.2 DL DCH -> DL DCH (Rate Decrease)

The DCH rate is decreased in order to:

Release some of the bandwidths of the subscriber to other subscribers to improve

the bandwidth utilization ratio when the required bandwidth for data transmiss ion of

the subscriber is decreased.

Lower the bandwidth of the subscriber and transmission power to ensure the QoS

for the subscriber when the downlink transmission power of the subscriber is too

high.

Lower the bandwidth of the subscriber and the system load to ensure the system

stability when the cell load is too high.

Therefore, the downlink DCH rate decrease can be triggered by the following factors:



Rate decrease triggered by downlink traffic

Rate decrease triggered by Node B downlink dedicated transmission power

Rate decrease triggered by cell downlink load

Rate decrease triggered by downlink resource congestion

Rate decrease triggered by mobility

Rate decrease triggered by DCH rate limitation in cell

Any of the above factors can trigger the rate decrease.

1. Rate decrease triggered by downlink traffic

The DCH to DCH switching for downlink rate decrease is based on the traffic

measurement report (Event 4B) on the user plane.

The Event 4B is defined as that the value of t raffic measurement is smaller than an

absolute threshold. See 3.1.4.1Traffic Measurement for its detailed definition.

The DL rate decrease is triggered in the case of the following conditions:

The DCH rate adjustment triggered by traffic switch DchAdjRateSwch is open.

The system receives consecutive DchE4bThd traffic measurement reports (Event

4B) from the user plane. (Note: i f the system receives a traffic measurement report

(Event 4A) from the user plane when the receiving times are smaller than the

threshold, the corresponding counter is cleared.)

None-real-time I/B services: [current uplink rate of the UE is greater than or equal to

the rate threshold Rrach for RACH switching] or [downlink target rate is greater than

or equal to the rate threshold Rfach for FACH switching] (if the system switch

FachSwch for CELL_FACH switching is closed, the above condition is not taken

into consideration); real-time S services: current rate exceeds the GBR of RAB

allocation

In the case of rate increase of DCH, the target rate is calculated by the formula: max

(next rate level smaller than the current rate in DRBC downlink rate levels



DlRateAdjLev[MAX_NUM_RATE_ADJUST], GBR). The GBR of interactive and

background services is 0, and the GBR of streaming services is the GBR of RAB

allocation.

2. Rate decrease triggered by Node B downlink dedicated transmission power

The DCH to DCH switching for downlink rate decrease can be triggered by the Node B

downlink dedicated transmission power (Event A).

The Event A is defined as that the NodeB downlink dedicated t ransmission power

(D-TCP) is greater than an absolute threshold. The Event B s defined as that the NodeB

downlink dedicated transmission power (D-TCP) is smaller than an absolute threshold.

See 3.1.4.3Node B Dedicated TCP Measurement for detailed definitions.

The DCH rate decrease is triggered in the case of the following conditions:

The DCH rate adjustment triggered by D-TCP switch DlPwrDasf is on.

The system receives consecutive DtcpEaThd measurement reports (Event A) of

Node B D-TCP, that is, the UE is in A state. (Note: i f the system receives a

measurement report (Event B) by Node B when the receiving times are smaller than

the threshold, the corresponding counter is cleared.)

Non-real-time I/B services: current rate is greater than minimum rate in DCH (lowest

rate level configured by DlRateAdjLev[MAX_NUM_RATE_ADJUST] ); real-time S

services: current rate is greater than the GBR of RAB allocation




background services is 0, and the GBR of streaming service is the GBR in RAB

allocation.

3. Rate decrease triggered by cell downlink load

The DCH to DCH switching for DCH downlink rate decrease can be triggered by the

downlink load control of the cell.




The current cell load exceeds the overload threshold; (the downlink load is

determined by TCP. For details of overload threshold, see ZTE UMTS Overload

Control Feature Guide)


rate level configured by DlRateAdjLev[MAX_NUM_RATE_ADJUST]); real-time S





background services is 0, and the GBR of streaming services is the GBR in RAB

allocation.

For more details of load control, see ZTE UMTS Overload Control Feature Guide.

4. Rate decrease triggered by downlink resource congestion

The DCH to DCH switching for DCH downlink rate decrease can be triggered by the

downlink resource congestion of the cell.


The downlink CE resources, code resources or power are congested.


rate level configured by DlRateAdjLev[MAX_NUM_RATE_ADJUST]); real-time S





background services is 0, and the GBR of streaming services is the GBR in RAB

allocation.

For more details of congestion control, see ZTE UMTS Congestion Control Feature

Guide.

5. Rate decrease triggered by mobility



The UE performs hard handover from one R99 cell to another due to mobility, if the

subscriber downlink admission at the current rate fails in the target cell, the system uses

the minimum DRBC rate to admit the user again. The minimum rate is min (max (lowest

level of DRBC downlink rate levels DlRateAdjLev[MAX_NUM_RATE_ADJUST], DL

GBR), DL MaxBR).

For more details of mobility, see ZTE UMTS handover Control Feature Guide .

6. Rate decrease triggered by DCH rate limitation in cell

Take the 6000ms as period, checking periodically whether there exist NRT or RT

services which exceed DCH rate limitation NrtMaxDlRateDch or RtMaxDlRateDch. If so,

choose no more than 5 users to decrease rate, and the NRT traffic target rate is

NrtMaxDlRateDch and NRT traffic target rate is RtMaxDlRateDch

3.1.3.3 UL DCH -> UL DCH (Rate Increase)

1. Rate increase triggered by uplink traffic .

The DCH to DCH switching for uplink rate increase is based on the traffic measurement

report (Event 4A) by the UE and determined by the cell's dedicated transmission power

and cell load.

The 4A event is defined as the t raffic measurement larger than an absolute threshold.

See 3.1.4.1Traffic Measurement for its detailed definition.

The uplink DCH rate increase is triggered in the case of the following conditions:


The system receives consecutive DchE4aThd traffic measurement reports (Event

4A) from the UE. (Note: if the system receives a traffic measurement report (Event

4B) from the UE when the receiving times are smaller than the threshold, the

corresponding counter is cleared)

If the system receives the measurement reports (Event 6B) triggered by UE

transmission power, that is, UE uplink transmission power is in 6B state (Note: for

details, see 3.1.4.2UE internal TxP Measurement)



The uplink load of the cell is not overloaded (Note: the uplink load is d etermined by

RTWP. For details, see ZTE UMTS Overload Control Feature Guide)

For non-macro diversity, in the case of DCH rate increase:

the target rate of NRT DCH is min (next rate level greater than the current rate in the

DRBC uplink rate levels UlRateAdjLev[MAX_NUM_RATE_ADJUST], DCH Limited

Rate, UL MaxBR). The MaxBR is the maximum bit rate during RAB allocation.

the target rate of RT DCH is min (next rate level greater than the current rate in the

DRBC downlink rate levels UlRateAdjLev[MAX_NUM_RATE_ADJUST], DCH Limited

Rate, UL MaxBR).

For macro diversity, in the case of DCH rate increase:

the target rate of Nrt Uplink DCH rate is min (next rate level greater than the current rate

in DRBC uplink rate levels UlRateAdjLev[MAX_NUM_RATE_ADJUST] , UL MaxBR,

DCH Limited Rate, MaxRateMD).

the target rate of Rt Downlink DCH rate is min (next rate level greater than the current

rate in DRBC Uplink rate levels UlRateAdjLev[MAX_NUM_RATE_ADJUST], UL MaxBR,

DCH Limited Rate, MaxRateMD).

Here, for the DCH Limited Rate explanation, please see 3.1.2.5; The MaxRateMD is

the maximum rate threshold allowed for DCH when the UE is in macro diversity.

In addition, in case of the concurrence of C (CS) services and PS (S/I/B) services, the

additional principles of PS service rate increase are as follows:

Determine the maximum rate threshold of NRT PS (I/B) services by distinguish the

rates of C (CS) services themselves.

If the rate of C (CS) services is less than or equal to CRateThrd, the sum of

uplink rates of concurrent PS services of NRT can not exceed

UlPsRateLmtLowC

If the rate of C (CS) services exceeds CRateThrd, the sum of uplink rates of

concurrent PS services of NRT can not exceed UlPsRateLmtHighC



The rate of streaming services is not restricted by the above rate threshold.

3.1.3.4 UL DCH -> UL DCH (Rate Decrease)

The DCH rate is decreased in order to:

Release some of the bandwidths of the subscriber to other subscribers to improve

the bandwidth utilization ratio when the required bandwidth for data transmission of

the subscriber is decreased.

Lower the bandwidth of the subscriber and transmission power to ensure the QoS

for the subscriber when the uplink transmission power of the subscriber is too high.

Lower the bandwidth of the subscriber and the system load to ensure the system

stability when the cell load is too high.

Therefore, the uplink DCH rate decrease can be triggered by various factors, such as:

Rate decrease triggered by uplink traffic

Rate decrease triggered by UE uplink dedicated transmission power

Rate decrease triggered by cell uplink load

Rate decrease triggered by uplink resource congestion.

Rate decrease triggered by mobility

Rate decrease triggered by DCH rate limitation in cell

Any of the above factors can trigger the rate decrease.

1. Rate decrease triggered by uplink traffic

The DCH to DCH switching for uplink rate decrease is based on the traffic measurement

report (Event 4B) from the user plane.


absolute threshold. See 3.1.4.1Traffic Measurement for its detailed definition.





If the system receives consecutive DchE4bThd traffic measurement reports (Event

4B) of the UE. (Note: if the system receives a traffic measurement report (Event 4A)

by the UE when the receiving times are smaller than the threshold, the

corresponding counter is cleared)

None-real-time I/B services: [current uplink rate of the UE is greater than or equal to

the rate threshold Rrach for RACH switching] or [downlink target rate is greater than

or equal to the rate threshold Rfach for FACH switching] (if the system switch

FachSwch for CELL_FACH switching is closed, the above condition is not taken

into consideration); real-time S services: current rate exceeds the GBR of RAB

allocation

The target rate of DCH rate decrease is max (next rate level smaller than the current rate

in DRBC uplink rate levels UlRateAdjLev[MAX_NUM_RATE_ADJUST], GBR). The GBR

of interactive and background services is 0, and the GBR of streaming services is the

GBR in RAB allocation.

2. Rate decrease triggered by UE uplink dedicated transmission power

The DCH to DCH switching for uplink rate decrease can be triggered by the UE uplink

dedicated transmission power (Event 6A). When the UE is far away from the base station

and its transmission power reaches the maximum, the UL DCH rate can be decreased to

lower the UE transmission power to avoid interference with other subscribers. When the

UE comes close to the base station, the traffic can trigger the UL DCH rate increase.

The Event 6A is defined as that the UE dedicated transmission power exceeds an

absolute threshold, namely, the UE is in high power status. For specific configurations of

threshold, see 3.1.4.2UE internal TxP Measurement .


The DCH rate adjustment triggered by UE dedicated transmission power switch

UlPwrDasf is on.



Receive the measurement reports (Event 6A) triggered by UE transmission power,

that is, the UE transmission power is in 6A state.


rate level configured by UlRateAdjLev[MAX_NUM_RATE_ADJUST]); real-time S

services: current rate is greater than the GBR in RAB allocation

The target rate of DCH rate decrease is max (next rate level smaller than the cur rent rate




3. Rate decrease triggered by cell uplink load

The DCH to DCH switching for DCH uplink rate decrease can be triggered by the uplink

load control of the cell.


The current uplink cell load exceeds the overload threshold; (the uplink load is

determined by RTWP. For details of overload threshold, see ZTE UMTS Overload

Control Feature Guide)


rate level configured by UlRateAdjLev[MAX_NUM_RATE_ADJUST] ); real-time S






4. Rate decrease triggered by uplink resource congestion

The DCH to DCH switching for DCH uplink rate decrease can be triggered by the uplink

resource congestion of the cell.




The CE uplink resources or power are congested.


rate level configured by UlRateAdjLev[MAX_NUM_RATE_ADJUST] ); real-time S






For more details of congestion control, see ZTE UMTS Congestion Control Feature

Guide.

5. Rate decrease triggered by mobility

When the UE performs hard handover from one R99 cell to another due to mobility, if the

subscriber uplink admission at the current rate fails in a target cell, the system uses the

minimum DRBC rate to admit the subscriber again. The minimum rate is min (max

(lowest level of DRBC uplink rate levels UlRateAdjLev[MAX_NUM_RATE_ADJUST], UL

GBR), UL MaxBR).

For more details of mobility, see ZTE UMTS handover Control Feature Guide .

6. Rate decrease triggered by DCH rate limitation in cell

Take the 6000ms as period, checking periodically whether there exist NRT or RT

services which exceed DCH rate limitation NrtMaxDlRateDch or RtMaxDlRateDch. If so,

choose no more than 5 users to decrease rate, and the NRT traffic target rate is

NrtMaxDlRateDch and NRT traffic target rate is RtMaxDlRateDch

3.1.3.5 CELL_DCH(DL DCH/ UL DCH) CELL_FACH(DL FACH/UL RACH)

1. CELL_DCH CELL_FACH channel switching triggered by traffic

i CELL_DCH (DL DCH/UL DCH ) -> CELL_FACH (DL FACH/UL RACH)

When the UE is in the CELL_DCH (DL DCH/UL DCH) state, the switching from



CELL_DCH (DL DCH/UL DCH) to CELL_FACH (DL FACH/UL RACH) can be

triggered by the traffic measurement report (Event 4B) from the user plane and UE.


absolute threshold. For details, see 3.1.4.1Traffic Measurement .

The switching from CELL_DCH (DL DCH/UL DCH) to CELL_FACH (DL FACH/UL RACH)

is triggered in the case of the following conditions:

The system switch FachSwch for CELL_FACH switching is open.

The services are interactive or background services.

The system receives consecutive ToFtimesThr traffic measurement reports

(Event 4B) from the user plane and UE,and switch is triggered by downlink

report.(Note: if the system receives a traffic measurement report (Event 4A)

from the user plane or UE when the receiving times are smaller than the

threshold, the calculator is clear.)

The downlink target rate of the UE is smaller than the maximum downlink rate

threshold Rfach, and the current uplink rate is smaller than the maximum

uplink rate threshold Rrach (Note: if the rate is at the lowest rate level

configured by UlRateAdjLev[MAX_NUM_RATE_ADJUST] and

DlRateAdjLev[MAX_NUM_RATE_ADJUST], the above condition is not taken

into consideration.)

When in macro diversity state, all the best radio link belongs to S-RNC;

otherwise the DL DCH/UL DCH rate is to be decreased.

If the concurrent services exist, it is required that all the services should meet the

condition for switching to CELL_FACH.

If the condition for CELL_FACH switching is met, but the the admission for

CELL_FACH fails, and current uplink or downlink rate is greater than the minimum

rate that UL DCH or DL DCH can bear, namely, the lowest rate level configured by


DlRateAdjLev[MAX_NUM_RATE_ADJUST], UL DCH or DL DCH rate decrease is

selected.



ii CELL_FACH (DL FACH/UL RACH) -> CELL_DCH (DL DCH/UL DCH)

When the UE is in the CELL_FACH (DL FACH/UL RACH) state, the switching from

CELL_FACH (DL FACH/UL RACH) to CELL_DCH (DL DCH/UL DCH) can be

triggered by the traffic measurement report (Event 4A) from the user plane or UE.

The switching from CELL_FACH (DL FACH/UL RACH) to CELL_DCH is triggered in

the case of the following conditions:

The system receives consecutive FachE4aThd measurement reports of Event

4A about traffic from the user plane or UE.

The cell is not overloaded (Note: the uplink load is determined by RTWP, while

the downlink load is determined by TCP. For overload threshold, see ZTE

UMTS Overload Control Feature Guide )

The rate of DL DCH/UL DCH is the initial rate of DRBC after the CELL_DCH

switching, which is [UL initial rate, DL initial rate] (see 3.1.2.2) The GBR of

interactive and background services is 0.

2. CELL_DCH to CELL_FACH channel switching triggered by load

The switching from CELL_DCH (DL DCH/UL DCH) to CELL_FACH can be triggered by

the cell load.

The switching from CELL_DCH (DL DCH/UL DCH) to CELL_FACH (DL FACH/UL RACH)

is triggered in the case of the following conditions:


The downlink cell load exceeds the overload threshold (Note: the downlink

load is determined by TCP. For the overload threshold, see ZTE UMTS

Overload Control Feature Guide)

3.1.3.6 CELL_DCH (DL DCH/UL DCH ) -> URA_PCH

When the UE uses the CELL_DCH(DL DCH/ UL DCH) for service bearer, the switching

from CELL_DCH (DL DCH/UL DCH) to URA_PCH can be triggered by the traffic



measurement report (Event 4B0) from the user plane and UE.

The Event 4B0 is defined as that the value of traffic measurement value is 0. See

3.1.4.1Traffic Measurement for its detailed definition.

The switching from CELL_DCH (DL DCH/UL DCH) to URA_PCH is triggered in the case

of the following conditions:

The system switch PchSwch for URA_PCH switchingis open.


The system receives consecutive DToPchThd traffic measurement reports with

measurement value of 0 from the user plane and UE (Note: if the system receives a

report with measurement value of non-zero value when the receiving times are

smaller than the threshold, the corresponding counter is cleared)

When in macro diversity status, all the best radio links belong to S-RNC.

If the concurrent services exist, it is requi red that all the services should meet the

condition for switching to URA_PCH.

If the concurrence of CS and PS services or multiple PS services occurs, and both the

uplink and downlink traffic measurement values of a PS I/B service are 0, and then the

system receives consecutive DToPchThd traffic measurement reports of Event 4B0 from

the user plane and UE: if GResPara4 is set to 0:support PS (0 kbps/0 kbps), the rate of

the PS service is decreased to 0 kbps /0 kbps, and keep in CELL_DCH state without

switching; if GResPara4 is set to 1:not support PS (0 kbps/0 kbps ), the rate of the PS

service is decreased to the minimum DRBC rate.

3.1.3.7 CELL_FACH (DL FACH/UL RACH) URA_PCH

1. CELL_FACH (DL FACH/UL RACH) -> URA_PCH

When the UE uses the CELL_FACH to bear the interactive and background services, the

switching from CELL_FACH to URA_PCH can be triggered by the traffic measurement

report (Event 4B0) from the user plane and UE.

The switching from CELL_FACH to URA_PCH is triggered in the case of the following



conditions:

The system switch PchSwch for URA_PCH switching is open.

The system receives consecutive FToPchThd traffic measurement reports with

measurement value of 0 by user plane and UE (Note: i f the system receives a

report with measurement value of non-zero value when the receiving times are

smaller than the threshold, the corresponding counter is cleared)


condition for switching to URA_PCH.

2. URA_PCH -> CELL_FACH (DL FACH/UL RACH)

When the UE in URA_PCH state originates the cell update message due to uplink or

downlink data transmission requirements or for new service setup, the system allocates

the channel by the UE service type before the UE is handed over to PCH by the process

of initial service channel allocation. This applies to interactive and background services.

3.1.3.8 CELL_DCH (DL DCH/UL DCH ) -> IDLE

When the UE uses the CELL_DCH for service bearer, the switching from CELL_DCH to

IDLE is triggered in the case of the following conditions:


The system receives consecutive DToIdleThd traffic measurement reports with

measurement value of 0 from the user plane and UE. (Note: If the system receives the

measurement reports with traffic measurement value of non-zero value when the

receiving times are smaller than the threshold, the corresponding counter is cleared.)


condition for switching to IDLE.

When the channel is switched to IDLE, the occupied radio resources are released and

the UE returns to the standby status.



3.1.3.9 CELL_FACH (DL FACH/UL RACH) -> IDLE

When the UE uses the CELL_FACH to bear the interactive and background services, the

switching from CELL_FACH to IDLE is triggered in the case of the following conditions:

The system receives consecutive FToIdleThd traffic measurement reports with

measurement value of 0 from the user plane and UE. (Note: If the system receives the

measurement reports with traffic measurement value of non-zero value when the

receiving times are smaller than the threshold, the corresponding counter is cleared.)


conditions for switching to IDLE.

When the channel is switched to IDLE, the occupied radio resources are released and

the UE returns to the standby status.

3.1.3.10 URA_PCH -> IDLE

When the time that the UE resides in the PCH status exceeds the threshold

PchHoldTimeThr, the UE is handed over to the IDLE status and the RRC connection is

released.

3.1.3.11 Uplink and downlink reconfiguration in one step

Uplink and downlink reconfiguration in one step is used for the scene when UL DCH and

DL DCH of the same RBs rate reconfiguration happens in succession during a short time.

This function can reduce the signaling messages on Uu interface. .

Uplink and downlink reconfiguration in one step is only applied to the channel

reconfiguration triggered by traffic volume measurement. The channel reconfiguration

triggered by other factors will be performed directly.

When DrbcSwch is UL&DL both on, the uplink and downlink reconfiguration in one step

scenes are as following:

UL DCH -> UL DCH(rate increase)based on traffic volume

If UL DCH satisfies the rate increase conditions in advance, start the timer



UpUdRecfgTimer

If before the timer UpUdRecfgTimer expires, DL DCH also satisfies the rate increase

conditions triggered by traffic volume, the uplink and downlinks rate increase

reconfiguration in one step is tried, if the admission decision is failed, try DL rate increase,

if it fails again , then go on to try UL rate increase.

If before the timer UpUdRecfgTimer expires, DL DCH satisfies the rate decrease

conditions triggered by traffic volume, the uplinks rate increase and downlink s rate

decrease reconfiguration in one step is tried, if the admission decision for uplinks rate

increase is failed, then go on to perform DL rate decrease reconfiguration.

If before the timer UpUdRecfgTimer expires, UL DCH does not satisfy the rate increase

conditions anymore, stop the UpUdRecfgTimer, and do not reconfigure UL DCH.

If the timer UpUdRecfgTimer expires, only UL rate increase reconfiguration is tried .

DL DCH -> DL DCH(rate increase)based on traffic volume

If DL DCH satisfies the rate increase conditions in advance, start the timer

UpUdRecfgTimer

If before the timer UpUdRecfgTimer expires, UL DCH also satisfies the rate increase

conditions triggered by traffic volume, the uplink and downlinks rate increase

reconfiguration in one step is tried, if the admission decision is failed, try DL rate increase,

if it is failed again, then go on to try UL rate increase.

If before the timer UpUdRecfgTimer expires, UL DCH satisfies the rate decrease

conditions triggered by traffic volume, the uplinks rate decrease and downlink s rate

increase reconfiguration in one step is tried, if the admission decision for DL rate

increase is failed, then go on to perform UL rate decrease reconfiguration.

If before the timer UpUdRecfgTimer expires, DL DCH does not satisfy the rate increase

conditions anymore, stop the UpUdRecfgTimer, and do not reconfigure DL DCH.

If the timer UpUdRecfgTimer expires, only DL rate increase reconfiguration is tried .

UL DCH -> UL DCH(rate decrease)based on traffic volume



If UL DCH satisfies the rate decrease conditions in advance, start the timer

DnUdRecfgTimer

If before the timer DnUdRecfgTimer expires, DL DCH also satisfies the rate decrease

triggered by traffic volume, the uplink and downlinks rate decrease reconfiguration in

one step is performed,.

If before the timer DnUdRecfgTimer expires, DL DCH satisfies the rate increase

triggered by traffic volume, the uplinks rate decrease and downlink s rate increase

reconfiguration in one step is tried, if the admission decision for DL rate increase is failed,

then go on to perform UL rate decrease reconfiguration..

If before the timer DnUdRecfgTimer expires, UL DCH does not satisfy the rate decease

conditions anymore, stop the UpUdRecfgTimer, and do not reconfigure UL DCH.

If the timer DnUdRecfgTimer expires, only UL rate decrease reconfiguration is

performed.

DL DCH -> DL DCH(rate decrease)based on traffic volume

If DL DCH satisfies the rate decrease conditions in advance, start the timer

DnUdRecfgTimer

If before the timer DnUdRecfgTimer expires, UL DCH also satisfies the rate decrease

conditions triggered by traffic volume, the uplink and downlinks rate decrease

reconfiguration in one step is performed,

If before the timer DnUdRecfgTimer expires, UL DCH satisfies the rate increase

conditions triggered by traffic volume, the uplinks rate increase and downlink s rate

decrease reconfiguration in one step is tried, if the admission decision for UL rate

increase is failed, then go on to perform DL DCH rate decrease reconfiguration .

If before the timer DnUdRecfgTimer expires, DL DCH does not satisfy the rate decease

conditions anymore, stop the DnUdRecfgTimer, and do not reconfigure DL DCH.

If the timer DnUdRecfgTimer expires, only DL rate decrease reconfiguration is

performed.



3.1.4 Related Measurement

3.1.4.1 Traffic Measurement

The traffic measurement includes the BO measurements of UTRAN and UE service

buffer capacities, which are respectively measured from the user plane and UE.

RLC mode of Traffic measurement report is decided by MeasRptTrMod. If AM mode is

selected, RNC will require UE retransmit error or discontinue SDU. If UM mode is

selected, ret ransmission is not available. The quantity of traffic measurement is

controlled by MeasQuantity; MeasQuantity could be 1:RLC buffer payload, 2:Average

RLC buffer payload 3:Variance of RLC buffer payload. In traffic measurement control

message, whether report the RLC BO is indicated by RptRlcBufInd, average RLC BO is

indicated by RptRlcAveInd and variance of RLC BO is indicated by RptRlcVarInd ..

For services using AM RLC mode to transmit data, the BO value of a RB is the sum of

RLC queue-to-send, retransmission queue, and data in logical channel. The user plane

uses the average of BO sample values collected in AverageTime to trigger the event.

The UE uses BO sample values collected in 20 ms to trigger the event. In traffic

measurement control message, Periodical Reporting / Event Trigger Reporting Mode IE

take the value of RptCrt.

Related events with traffic measurement include:

Event 4A: the event is triggered when the traffic measurement value exceeds an

absolute threshold and this condition lasts for a certain period

(TrigTime[MAX_UE_TRV_MEAS_EVENT] ). Delay timer

PendingTime[MAX_UE_TRV_MEAS_EVENT] is set to prevent triggering frequently

the event.

Event 4B: the event is triggered when the traffic measurement value is smaller than

an absolute threshold and this condition lasts for a certain period

(TrigTime[MAX_UE_TRV_MEAS_EVENT] ). Delay timer

PendingTime[MAX_UE_TRV_MEAS_EVENT] is set to prevent triggering frequently

the event.

Event 4B0: the event is triggered when the traffic measurement value is 0 and this



condition lasts for a certain period (TrigTime[MAX_UE_TRV_MEAS_EVENT]). 4B0

event is an exceptional case in 4B events, its delay timer

PendingTime[MAX_UE_TRV_MEAS_EVENT] is the same as that of 4B event.

Where, the absolute thresholds for different channels acquire different parameters, which

is as below. TrigTime[MAX_UE_TRV_MEAS_EVENT] is the interval between the time

when the event is observed and the time when the event is reported.

PendingTime[MAX_UE_TRV_MEAS_EVENT] is the screening period during which the

event which has occurred is prevented from reoccurring. The following figure shows the

report of 4A event based on the principles of trigger time and pending time.

Figure 3-2 Event Triggering of Traffic Measurement

Traffic Volume

Thr_4A

Trigger

Time

Pending

TimePending

TimeTrigger

Time

Trigger

Time

Report 4A Report 4A Report 4A

The time of trigger channel switching is calculated as below:

Time = Counter Threshold* TiggerTime + (Counter Threshold - 1)*PendingTime

The absolute threshold (such as parameter RptThres[MAX_UE_TRV_MEAS_EVENT] )

is configured as follows:

The smaller the threshold value of 4A event is, the quicker the system responses to

the service demand of the UE, and the sooner the bandwidth increase is triggered,

so as to allocate more radio resources. And vice versa.

The bigger the threshold value of 4B event is, the quicker the system responses to

the service demand of the UE, and the sooner the occupied bandwidth is decreased.

And vice versa.



The parameters TrigTime[MAX_UE_TRV_MEAS_EVENT] and PendingTime[MAX

_UE_TRV_MEAS_EVENT] are configured as follows:

The smaller the value of TrigTime[MAX_UE_TRV_MEAS_EVENT] for 4A event is,

the quicker the control plane receives the reports and increases the bandwidth

when the traffic measurement meets the threshold for triggering the event 4A.

Therefore, the demand of service rate of UE is reflected in a better way. And vice

versa. However, if the parameter is configured with a very low value, the system will

response to the service demand which fluctuates in a ve ry short moment, resulting

in unnecessary bandwidth increase.

The smaller the value of PendingTime[MAX_UE_TRV_MEAS_EVENT] for 4A event

is, the quicker the control plane receives consecutively the reports and increases

the bandwidth when the traffic measurement meets the threshold for triggering the

event 4A. Therefore, the demand of service rate of UE is reflected in a better way.

And vice versa. However, if the parameter is configured with a very low value,

reporting event 4A will resulting in considerable bandwidth occupation.

The smaller the value of TrigTime[MAX_UE_TRV_MEAS_EVENT] for 4B event is,

the quicker the control plane receives consecutively the reports and decreases the

bandwidth when the traffic measurement meets the threshold for triggerin g the

event 4B. Therefore, the demand of service rate of UE is reflected in a better way.

And vice versa. If the parameter is configured with a very low value, the system will

response to the service demand which fluctuates in a very short moment, resultin g

in unnecessary bandwidth decrease.

The smaller the value of PendingTime[MAX_UE_TRV_MEAS_EVENT] of 4B event

is, the quicker the control plane receives consecutively the reports and decreases

the bandwidth when the traffic measurement meets the threshold for triggering the

event 4B. Therefore, the demand of service rate of UE is reflected in a better way.

And vice versa. However, if the parameter is configured with a very low value,

reporting event 4B will resulting in considerable bandwidth occupation. Therefore,

the feeling of subscriber and bandwidth utilization should be taken into

consideration before configuration.

The rate increase process is triggered when the control plane or UE receives the



consecutive reports of event 4A and the 4A_counter >= 4A_threshold; while the rate

decrease process is triggered when the control plane or UE receives the consecutive

reports of event 4B and the 4B_counter > =4B_threshold. Where, 4A_threshold and

4B_threshold are configured with different OMC parameters based on different types of

channel switching. The figure below shows the rate adjustment process (no event

counter configured):

Figure 3-3 Rate Adjustment Triggered by Traffic

time-to-trigger

pending-time-after-trigger

time-to-trigger

pending-time-after-trigger

Reporting event

4A

Increasing RateReporting event

4B

Decreasing RateThr_4A

Thr_4B

Report

4A

Report

4B

The traffic measurement uses the parameter MeasEvtNum to define its number (2 at

present) of events. The two events are the event 4A and event 4B corresponding to

parameter MeaEvtId[MAX_UE_TRV_MEAS_EVENT] which are valid only for event

reporting.

Parameter TxInterCfgPre[MAX_UE_TRV_MEAS_EVENT] decide whether forbid RACH

data after measurement report., and the forbidden time is decided by

TxInterruption[MAX_UE_TRV_MEAS_EVENT] .

Measure parameter acquisition method: when the traffic parameter is obtained, obtain

the corresponding configuration number UeTrvMCfgNo from the UE traffic measurement

configuration of the cell based on the cell identity Cid and measurement target (uplink

DCH traffic measurement DrbcDchUeEvt, downlink DCH traffic measurement

DrbcDchUp, RACH traffic measurement DrbcRachUeEvt, and FACH traffic

measurement DrbcFachUp), and then follow the following path to obtain corresponding

traffic measurement parameter based on the configuration number: RNC NE -> RNC



Radio Resource Management -> Modify Advanced Parameter -> UE Traffic Volume

Measurement Configuration:

If the uplink channel for service bearer is the DCH, the traffic is measured on the UE

side, and if the related parameter which is adopted to measure the traffic is the

corresponding parameter of UE Traffic Volume Event Measurement Configuration

Number for DCH:

The 4A /4B threshold of every uplink DCH rate level adopts the parameters

under this configuration number. Such as, 8kbps uses the value of

RptThres0[MAX_UE_TRV_MEAS_EVENT], 16kbps uses the value of






RptThres6[MAX_UE_TRV_MEAS_EVENT].

The values of TrigTime[MAX_UE_TRV_MEAS_EVENT] and

PendingTime[MAX_UE_TRV_MEAS_EVENT] of event 4A and 4B of uplink

DCH are the values under corresponding configuration number.

If the downlink channel for service bearer is the DCH, the traffic is measured on the

user plane side, and if the related parameter which is adopted to measure the traffic

is the corresponding parameter of UP Traffic Volume Measurement Configuration

Number for DCH:

The 4A /4B threshold of every downlink DCH rate level adopts the parameters

under this configuration number. Such as, 8kbps uses the value of





RptThres4[MAX_UE_TRV_MEAS_EVENT], 256kbps u

Documents

148521323 ZTE UMTS DRBC Algorithm Feature Guide V6!1!201204