Huawei PS-Parameters of GPRS Network Optimization

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Parameters of GPRS Network Optimization www.huawei.com

Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.


Foreword

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

Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved. Page1


Contents GPRS Cell Parameters Parameters of Cell Reselection Performance Parameters



GPRS Cell Parameters

NMO

T3168

T3192

DRX_TIMER_MAX

ACCESS_BURST_TYPE

CONTROL_ACK_TYPE

BS_CV_MAX

PAN

T3172



NETWORK_MODE

Network Mode

I

Configure Gs

Yes

Configur e PCCH

Yes

II

No

No

III

No

Yes

Channel for circuit paging

GPRS Paging Channel

PPCH

PPCH

PCH

PCH

PACCH

-

PCH

PCH

PCH

PPCH

PCH

PCH

Idle Mode PCCCH Or CCCH

Dedicated

PACCH

CCCH

CCCH

CCCH

CCCH



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

T3168

PACKET UPLINK ASSIGNMENT

Condiction

T3168 recommendation（ms）

Very Good

500

Good

1000

Bad

2000



T3192 The timer is for the MS to wait for TBF release after receiving the last data block. PCU PACKET DOWNLINK ACK/NACK （FAI=1） Final ACK Identifier

T3192 PACKET DOWNLINK ASSIGNMENT TFI

value（ms） 500

1000

1500

0

80

120

160


200


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

Non_DRX

Packet transmission mode

Non_DRX

Packet idle mode

DRX

Packet idle mode

DRX_TIMER_MAX (s)

Value（Sencond） 0

1

2

4

8

16

32

64



Packet Signaling Processing RLC DATA BLOCK RLC DATA BLOCK (FBI) PACKET DOWNLINK ACK/NACK （FAI=1）

T3192=500ms Ready Mode Non DRX mode= 4s

DRX mode

DRX mode



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

PACKET CHANNEL REQUEST

PTCCH UPLINK BLOCK

PACKET CONTROL ACKNOWLEDGMENT



BS_CV_MAX PCU CV=X

设BS_CV_MAX=10

RLC DATA BLOCK

T3198

RLC DATA ACK

200ms

CV=X

RLC DATA BLOCK Timeout



BS_CV_MAX suppose BS_CV_MAX=3

CV=0

CV=1

CV=2

CV=3

CV=15

PCU

CV=15

CV=15

CV=15

CV=3

CV=15

CV=15

MS buffer – UL RLC blocks More data

CV=0

CV=1

CV=2



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

N3102

Packet Uplink Ack/Nack - PAN_DEC + PAN_INC

PAN_MAX

Abnormal Release Perform Cell Re-selection

T3182 T3182

T3182 T3182

T3182



PAN PCU RLC DATA BLOCK

设PAN_INC=2

PACKET DATA ACK N3102+2

RLC DATA BLOCK T3182 PACKET DATA ACK N3102- 1 Timeout Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved. Page13

设PAN_DEC=1


T3172 WAIT_INDICATION PCU PACKET CHANNEL REQUEST PACKET ACCESS REJECT Phase I

T3172 PACKET CHANNEL REQUEST

PACKET RESOURCE REQUEST PACKET ACCESS REJECT

T3172

Phase II

PACKET RESOURCE REQUEST



Compare with GSM GPRS

GSM

T3168

S

PAN

RLT(SACCH Mul-frame)

T3172

T3122






NETWORK_CONTROL_ORDER

Description

Whether the MS send the M.R

MS 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



NC2 Feature

change to cell C

Neighbor cell B

Neighbor cell c

Serving cell A



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



GPRS Cell Change on Standby Mode NC2 > SC2+CRH RA 2

RA 1 CC2>BC2＋CRH

AC2>BC2 Cell B Cell A

Cell C



GPRS Cell Change on Ready Mode NC2 > SC2+CRH

RA 1 BC2>AC2＋CRH Cell A

Cell B



NACC Value Range

Yes, No

Description

This parameter indicates whether the cell supports the Network Assisted Cell Change (NACC) function. The NACC function means that the network notifies the MS (in the packet transmission state) of the system information about the neighboring cells in advance in NC0, NC1, or NC2 network control mode. Thus the cell reselection of the MS is quickened. The BSC plays a minor role in the NACC function. It sends the system information about the cell and the information about the neighboring cells to the PCU instead of participating in the NACC processing.

Remarks

Set this parameter to Yes only when the cell supports GPRS services. This parameter requires the support of licenses.



NACC System information of cell B

Cell A

Cell B



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

1010

ALPHA Value

A=0.0

A=0.1

A=0.2

……

A=0.9

A=0.10

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



ALPHA & GAMMA

According GPRS principle, GPRS MS output power as below： Pch = Min〔 Ro - Rch – a*( C+48) , Pmax〕

Pmax: GPRS MS max transmitting power:29dBm a：ALPHA，normally is 1 Ro：BTS max transmitting power:39dBm Rch：GAMMA C：MS receiving level

If there is power control，Ro - Rch – a*( c+48) < Pmax 39－GAMMA －C－48 -38－GAMMA



ALPHA & GAMMA So if GAMMA=0，power control will be triggered when the receiving level higher than －38dB. But in the project network, normally receiving level lower than -38dB. The recommended value is 14，each unit is 2dB，so －38－2X14＝－ 66dB，when the MS receiving level higher than -66dB, power control will be triggered.






RAC Route Area Code

LA RA

RA

RAI = MCC+MNC+LAC+RAC

When RAC and LAI appear concurrently, the RAC is unique

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



RAC Route Area Update

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

new routing area

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

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



T3312

RA1

SGSN

RA2 Routing_Area_update_request Ready or Standby

Including T3312

Routing_Area_update_accept Routing_Area_update_complete



GPRS Coding Scheme A configuration command that sets the GPRS coding scheme of a cell UpFixCs

Meaning: fixed CS type of the uplink Value range: cs1, cs2, cs3, cs4, unfixed Explanation: fixed CS type of the uplink. To adopt the fixed CS type of the uplink, set this parameter to CS-1, CS-2, CS-3, or CS-4. To dynamically adjust the CS type of the uplink, set this parameter to unfixed. Default value: unfixed

UpDefaultCs

Meaning: default CS type of the uplink Value range: cs1, cs2, cs3, cs4 Explanation: default CS type of the uplink. To dynamically adjust the CS type of the uplink, set the CS type for transmitting the first TBF through this parameter. Then, the CS types of other TBFs are dynamically adjusted based on the signal transmission quality. Default value: cs1



GPRS Coding Scheme UpThdCsUpGrade1

Meaning: retransmission rate threshold for the uplink TBF to change from CS-1 to CS-2 Value range: 0-64 Explanation: When the retransmission rate of the uplink TBF is smaller than or equal to the value of this parameter, the code scheme of the uplink TBF changes from CS-1 to CS-2. Default value: 5

DnDefaultCs

Meaning: default CS type of the downlink Value range: cs1, cs2, cs3, cs4 To dynamically adjust the CS type of the downlink, set the CS type for transmitting the first TBF through this parameter. Then, the CS types of other TBFs are dynamically adjusted based on the signal transmission quality. Default value: cs2



GPRS Coding Scheme CS4 UpDefaultCs:CS2

UpThdCsUpGrade3:5

UpThdCsUpGrade3:2

CS3

UpThdCsUpGrade3:5

UpThdCsUpGrade2:3

CS2

Retrans rate:2

UpThdCsUpGrade3:10 UpThdCsUpGrade1:5

CS1



PDCH Channel Parameters Uplink Multiplex

Value range: 10-70

Threshold of Dynamic Explanation: Uplink multiplex threshold of dynamic channel Channel Conversion conversion. When the number of subscribers reaches this threshold, the dynamic channels are used. If this threshold is high, it is difficult to seize dynamic channels. If this threshold is low, it is easy to seize dynamic channels. Default value: 20 Downlink Multiplex

Value range: 10-80

Threshold of Dynamic Explanation: Downlink multiplex threshold of dynamic channel Channel Conversion conversion Default value: 20



PDCH Channel Parameters PDCH Uplink

Value range: 10-70

Multiplex Threshold

Explanation: The maximum downlink TBFs on one PDCH channel. If this threshold is set to a higher value, the TBFs established on the PDCH and the subscribers are more, and the uplink bandwidth for each subscriber is lower. Value 10 indicates a maximum of one TBF can be established on the PDCH. Default value: 70

PDCH Downlink

Value range: 10-80

Multiplex Threshold

Explanation: The maximum downlink TBFs on one PDCH channel Default value: 80



PDCH Channel Parameters Downlink Multiplex Threshold of Dynamic Channel Conversion:20

PDCH

PDCH

PDCH

PDCH

Dynamic PDCH PDCH

Dynamic PDCH PDCH

Dynamic PDCH PDCH

MS1

MS2 MS3


Dynamic PDCH PDCH


PDCH Channel Parameters



GPRS Channel Priority Type



GPRS Channel Priority Type Value Range

GPRS Channel, EGPRS Normal Channel, EGPRS Priority Channel, EGPRS Special Channel, None-GPRS Channel

Default Value

When Channel Type is set to non-PDTCH, the default value is None-GPRS Channel. When Channel Type is set to PDTCH and the cell does not support EDGE services, the default value is EGPRS Normal Channel. When Channel Type is set to PDTCH and the cell supports EDGE services, the default value is EGPRS Normal Channel.

Description

When Channel Type is set to non-PDTCH, the default value is None-GPRS Channel.When Channel Type is set to PDTCH and the cell does not support EDGE services, the default value is EGPRS Normal Channel.When Channel Type is set to PDTCH and the cell supports EDGE services, the default value is EGPRS Normal Channel.



GPRS Channel Priority Type TRX2 EGPRS Normal

EDGE MS

GPRS MS



GPRS Channel Priority Type TRX2 EGPRS

EGPRS Priority

Priority

×reject GPRS MS

EDGE MS GPRS MS



GPRS Channel Priority Type TRX2 EGPRS Priority

×release EDGE MS

GPRS MS



EDGESPARA



EDGESPARA

EDGE codec will be dynamically adjusted the MCS depended on BEP.

BEP：Bit Error Probability .Each radio block is consist of 4 bursts, there is a BEP value for each block, such as BEP1，BEP2，BEP3，BEP4.

Mean-BEP is the average of four BEPs, from BEP1 TO BEP4. MEAN_BEP= （BEP1+BEP2+BEP3+BEP4）/4. So Mean-BEP is the average quality of receiving signal.

CV_BEP is the result of standard deviation. It shows us the stability of receiving quality.



BEP Table BEP

8PSK MEANBEP

8PSK_CV_BEP 1

2

3

4

5

6

7

8

1

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

2

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

3

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

4

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

6

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-6

7

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-6

MCS-6

8

MCS-5

MCS-5

MCS-5

MCS-5

MCS-5

MCS-6

MCS-6

MCS-6

9

MCS-5

MCS-5

MCS-5

MCS-5

MCS-6

MCS-6

MCS-6

MCS-6

10

MCS-5

MCS-5

MCS-5

MCS-6

MCS-6

MCS-6

MCS-6

MCS-6

11

MCS-5

MCS-5

MCS-6

MCS-6

MCS-6

MCS-6

MCS-6

MCS-7

12

MCS-6

MCS-6

MCS-6

MCS-6

MCS-6

MCS-6

MCS-7

MCS-7

13

MCS-6

MCS-6

MCS-6

MCS-6

MCS-6

MCS-7

MCS-7

MCS-7

14

MCS-6

MCS-6

MCS-6

MCS-6

MCS-7

MCS-7

MCS-7

MCS-7

15

MCS-6

MCS-6

MCS-7

MCS-7

MCS-7

MCS-7

MCS-7

MCS-7



EDGESPARA LqcMode

Meaning: link quality control mode Value range: IR-0, LA-1 Explanation: link quality control mode Default value: LA

UpFixMcs

Meaning: fixed MCS type of the uplink Value range: MCS1-MCS9, unfixed Explanation: To adopt the fixed MCS type of the uplink, set this parameter to a value among MCS1-MCS9; to dynamically adjust the MCS type of the uplink, set this parameter to unfixed. Default value: unfixed



LA and IR

The network dynamically adjusts the coding scheme EDGE based on the link quality. The link quality is determined by 8PSK MEAN BEP and 8PSK CV BEP carried in the Packet EGPRS Downlink Ack/Nack message.

The network should retransmit different data blocks with the puncturing coding scheme. The MS buffers the history error information and the data blocks are retransmitted through combined error correction.



EDGESPARA DnFixMcs

Meaning: fixed MCS type of the downlink Value range: MCS1-MCS9, unfixed

UpDefaultMcs

Meaning: default MCS type of the uplink Value range: MCS1-MCS9 Explanation: To dynamically adjust the MCS type of the downlink, set the MCS type for transmitting the first TBF through this parameter. Then, the MCS types of other TBFs are dynamically adjusted based on the signal transmission quality. Default value: MCS3

DnDefaultMcs

Meaning: fixed MCS type of the downlink Value range: MCS1-MCS9, unfixed



N3101

N3101 will be increased by 1 every time no uplink data block is received. The TBF will be released by network if N3101 reaches the threshold.

MS

Network RLC block(with USF valid) RLC block (with USF valid)

NO RESPONSE FROM MS

N3101=N3101_MAX

A



N3103

N3103 will be incremented by 1 every time no “ACKOWNLEDGEMENET” message is received during TBF release.

MS

Network PACKET UPLINK ACK/NACK(FAI=1) PACKET UPLINK ACK/NACK(FAI=1)

NO RESPONSE FROM MS

N3103=N3103_MAX

A



N3105

Network will send the RLC data block with RRBP periodically to wait response message from MS. N3105 will be increased by 1 every time no ” PACKET DOWNLINK ACK/NACK” is received , otherwise N3105 will be reset.

MS

Network DOWNLINK DATA BLOCK (RRBP) DOWNLINK DATA BLOCK (RRBP) DOWNLINK DATA BLOCK (RRBP) MS no response.....

A



GPRS&EDGE Coding Scheme Kbps

59.2

60.00

54.4

50.00

GPRS

44.8

EGPRS

40.00

29.6

30.00 22.4

21.4

20.00 13.4

10.00 0.00

17.6

15.6

14.8

9.05

CS-1

8.8

CS-2

CS-3

CS-4

MCS-1

11.2

MCS-2

MCS-3

MCS-4

MCS-5

MCS-6

GMSK


MCS-7

8PSK

MCS-8

MCS-9


Appendix

Codec

Idle timeslot

CS1

CS2

CS3

CS4

MCS1

MCS2

MCS3

MCS4

1+0

1+1

MCS5

MCS6

MCS7

MCS8

1+2

1+3


MCS9


Appendix



Summary 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


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Thank you


Huawei PS-Parameters of GPRS Network Optimization

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