Huawei Gprs

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Parameters of GPRS Network Optimization

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The PCU performance parameters are essential to the GPRS network. Proper setting of such parameters can improve performance of the packet services.


Chapter 1 Chapter 1 GPRS Cell ParametersGPRS Cell Parameters

Chapter 2 Parameters of Cell Reselection Chapter 2 Parameters of Cell Reselection

Chapter 3 Chapter 3 Performance ParametersPerformance Parameters


Show Configuration

Configuration of Cell 1

Pcu show gprs 1


GPRS Cell Parameters

NMO

T3168

T3192

DRX_TIMER_MAX

ACCESS_BURST_TYPE

CONTROL_ACK_TYPE

BS_CV_MAX

PAN

T3172


NETWORK_MODE

Network Mode

ConfigureGs

Interface

Configure PCCCH

Channel for circuit paging

GPRS Paging

Channel

Idle Mode

Packet Transmitting

Mode

I Yes Yes

PPCH PPCH PCCCHOr

CCCHPACCHPCH PCH

PACCH -

II No No PCH PCH CCCH CCCH

III No YesPCH PPCH

CCCH CCCHPCH PCH


T3168 T3168 is used to set the maximum duration for the MS to wait for

the packet uplink assignment message

PCU

PACKET CHANNEL REQUEST

PACKET UPLINK ASSIGNMENT/ IMMEDIATE ASSIGNMENT COMMAND

PACKET RESOURCE REQUEST

Condition BLER T3168 recommendation （ ms）Very Good BLER<2% 500

Good 2%<BLER<5% 1000

Bad 5%<BLER<10% 2000

T3168 PACKET UPLINK ASSIGNMENT


T3192The timer is for the MS to wait for TBF release after receiving the last data block.

PCU

T3192

PACKET DOWNLINK ACK/NACK （ FAI=1）

PACKET DOWNLINK ASSIGNMENT

TFI

Final ACKIdentifier

T3192 codec 000 001 010 011 100 101 110 111

value （ ms） 500 1000 1500 0 80 120 160 200


DRX_TIMER_MAXThe MS request keeps the maximum value of non-DRX mode.

Packet transmission mode

Non_DRX DRX

Packet idle mode

Non_DRX

DRX_TIMER_MAX (s)

Parameter Value 0 1 2 3 4 5 6 7

Reserved Duration (s) 0 1 2 4 8 16 32 64

Packet idle mode


ACCESS_BURST_TYPE

MS uses 8bit format or 11bit format in the following three types of messages


PTCCH UPLINK BLOCK

PACKET CONTROL ACKNOWLEDGMENT


CONTROL_ACK_TYPE

Set the default format used by the MS in the control acknowledgement message.

Parameter value 0: 4 access burst format

Parameter value 1: RLC/MAC control block format


BS_CV_MAX

PCU

T3198

RLC DATA BLOCK

CV=X

RLC DATA ACK

RLC DATA BLOCK

CV=X

Timeout

设 BS_CV_MAX=10

200ms


BS_CV_MAX

PCU

MS buffer – UL RLC blocks

CV=0 CV=1 CV=2 CV=3 CV=15 CV=15 CV=15 CV=15

CV=0 CV=1 CV=2More data CV=3 CV=15 CV=15

suppose BS_CV_MAX

=3


PAN PAN_DEC Set the decrease step length of the N3102 counter of the MS

PAN_INC Set the increase step length of the N3102 counter of the MS

PAN_MAX Set the maximum value of the N3102 counter of the MS

Packet Uplink Ack/NackN3102

PAN_MAX

- PAN_DEC+ PAN_INC

Abnormal Release

T3182

T3182

T3182 T3182

T3182

Perform Cell Re-selection


PAN

PCU

N3102+2

RLC DATA BLOCK

PACKET DATA ACK

Timeout

PAN_INC=2

RLC DATA BLOCK

PACKET DATA ACKT3182

PAN_DEC=1

N3102- 1


PAN

Parameters Value

PAN_INC 0 1 2 3 4 5 6 7 -

PAN_DEC 0 1 2 3 4 5 6 7 -

PAN_MAX 0 4 8 12 16 20 24 28 32


T3172WAIT_INDICATION

PCU

T3172


PACKET ACCESS REJECT


PACKET ACCESS REJECT

T3172

Phase I

Phase II




Chapter 1 Chapter 1 GPRS ParametersGPRS Parameters

Chapter 2 Parameters of Cell ReselectionChapter 2 Parameters of Cell Reselection



NETWORK_CONTROL_ORDER

Definition

Description

Whether the MS send the

M.RMS mode Cell Selection

Mode

NC0 Normal MS Control Mode No Ready & Standby Controlled by MS

NC1 MS Control with M.R Mode Yes Only Ready Controlled by MS

NC2 Network Control Mode Yes Only Ready Controlled by network


GPRS Cell Selection

If no PBCCH channel exists, the cell reselection of GPRS is basically the same as GSM cell reselection, only two situations are different.

when the MS on the standby mode ,if it occur the cell reselection to the other route area cell :

Nc2>Sc2+CRH

when the MS on the ready mode ,if it occur the cell reselection :

Nc2>Sc2+CRH


The GPRS puts forward new cell reselection algorithms C31 and C32 (applicable only when the PBCCH exists in the system).

C31 is a signal threshold criterion. It is also called signal level threshold criterion of Hierarchical Cell Structure (HCS), and is used to judge whether to adopt preference cell reselection.

C31(s) = RLA_P(s) - HCS_THR(s) (service cell)

C31(n) = RLA_P(n) - HCS_THR(n) - TO(n) * L(n) (adjacent cell)

GPRS Cell Selection


The C32 criterion is a perfection of C2 applied to GSM. It applies the offset

and the delay value to the cell reselection which needs execution of cell

update program or route update program. When the PBCCH channel does

not exist in the service cell, the MS will execute cell reselection according

to the C2 algorithm.

C32=C1 （ serving cell）C32=C1+ GPRS_RESELECT_OFFSET - GPRS_TEMPORARY_ OFFSET *H(GPRS_PENALTY _TIME – T) *(1-L) （ neighbor cell）

GPRS Cell Selection


In addition, it is necessary to consider different routing areas

If the MS is in the standby mode, and the adjacent cell and the service

cell are in the same routing area: C32 = C32

If the MS is in the ready mode, and the adjacent area and the service

area are in the same routing area:

C32 = C32+CELL_RESELECT_HYSTERESIS

If the MS is in the Ready or Standby ， and the adjacent area and

the service area are in the different routing area:

C32 = C32+RA_RESELECT_HYSTERESIS

GPRS Cell Selection


ALPHA & GAMMA ALPHA

The ALPHA parameter is used by the MS to calculate the output power value PCH

of its uplink PDCH

For open loop power control, it should be set to 1.0.

codec 0000 0001 0010 …… 1001 1010ALPHA Value

A=0.0 A=0.1 A=0.2 …… A=0.9 A=0.1

0 GAMMA

Expected receiving signal strength at the BTS side when the MS GPRS dynamic power control is active

Value range: 0~62dB, default value is 0


Chapter 1 Chapter 1 GPRS ParametersGPRS Parameters

Chapter 2 Parameters of Cell Reselection Chapter 2 Parameters of Cell Reselection



RAC

Route Area Code

When RAC and LAI appear concurrently, the RAC is unique When CI and LAI or RAI appear concurrently, the CI is unique

RAI = MCC+MNC+LAC+RAC

LA

RA RA


RAC

Route Area Update

When an MS to which the GPRS is attached discovers that it gets into a new route area

After timeout of the periodical Routing Area (RA) timer T3312

When a “suspended” MS is not “recovered” by network


T3312

Routing_Area_update_request

Routing_Area_update_accept

Routing_Area_update_complete

RA1RA2

SGSN

MS in Standby or Ready

stateInclude T3312


In this course, we have learned: The function of GPRS cell parameters

The function of GPRS cell selection parameters

The function of GPRS performance parameters

Summary

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