ibca introdution

HUAWEI TECHNOLOGIES CO., LTD.

www.huawei.com

Huawei Confidential

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Interference Based Channel

Allocation

HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential

Overview Mechanism Benefit Limitation


Overview IBCA is a dynamic frequency and channel

allocation algorithm based on the prediction of the achievable CIR of each candidate channel and connection established.

Pre-requirement: synchronization at air interface

Main function modules: CIR estimation Channel allocation


Parameter Setting

TCH Frequency Setting : RF Hopping is better HSN of all sites = 0 ; Frame Offset layout ; Major parameters in IBCA

Soft block threshold MAIO layout Waitting time for MR Etc…


CIR Estimation

Main Steps:Decide Interference relationInterference Probability

calculationPath Loss EstimationPath Loss MatrixCIR computationCIR Matrix

The CIR Estimatio

n is the basis of

Channel Alloati

on !


Decide Interference Relation

Input: Mobile

Allocation, Output: Interference

relation No interference Co-Channel

interference Adjacent

interference

Cell D

Cell A

Cell C

Cell B

Cell A

Cell B

Cell C

Cell D

8

5

5

20

ADJ

Cell C

Cell A

ADJ

Cell A

Cell C

CoCell D

Cell B

CoCell B

Cell DSER

VCell

INTFCell

Co-channel Interference Cell

Ad-channel Interference Cell

Legend:

No Interference


Interference Probability Calculation

Input: Moblie Allocation, MAIO, HSN, FrameNumber Offset

Output ： Interference Probability

Interfere

nce

Probabili

ty=100%

Interfere

nce

Probabili

ty=0%

example


Pathloss EstimationPathLoss (dB) = TRX_PWR_BCCH(dBm) - RxLevDLBCCH (dBm)

TRX_PWR_BCCH: Transmission power of BCCH TRX; RxLevDLBCCH : Signal strength of BCCH TRX measured by MS

Pathloss(B->A)=BS_PWR B-RxLevDL BPathloss(A->B) =BS_PWR B-RxLevDL BCELL A CELL B

MS A MS B

BS_PWR BBS_PWR A

RxLevDL B RxLevDL A


Pathloss Matrix

With all Cell-Cell Measured, we get a Pathloss Matrix on the basis of Interference Relation Matrix （ As show in the left)The Passloss Matrix tells how much is attenuated of the signal which travel from the Interfering Cell to the Serv Cell

Cell D

Cell A

Cell C

Cell B

Cell A

Cell B

Cell C

Cell D

8

5

5

20

5

Cell C

Cell A

5

Cell A

Cell C

20Cell D

Cell B

8Cell B

Cell DSER

VCell

INTFCell

Co-channel Interference Cell Ad-channel Interference CellLegend: No Interference

Signal Travel LossSignal Travel Loss


CIR Computation CIR(dB) ＝ SS_EFF(dBm) － SS_INTF(dBm)

SS_EFF: Effective Signal Strength SS_INTF: Interference Signal Strength

Effective_DL

Effective_UL

Interfere_DL

Interfere_UL DiagramDiagram

BSPWR Cell B

PathLoss (A->B)CELL A CELL B

MS A MS B

PathLoss (B->A)

BSPWR Cell A


CIR MatrixTRX

Tim

e slot

(0,3)

CELL A

0

1

2

3

4

5

6

7

0 1

(2,16)

(1,18)

(0,18)

\

(1,30)

\

(1,3)

(2,23)

(1,3)

\

(2,14)

\

(0,3)

(0,17)

(0,15)

TRX

Tim

e slot

(2,18)

CELL B

0

1

2

3

4

5

6

7

0 1

(0,15)

\

(2,18)

(1,21)

(2,12)

\

\

(1,23)

\

(1,16)

(1,23)

(0,33)

(2,19)

(2,31)

\

New Assigned Channel

is only interfered by

the same TS of the

interfering Cell

(MAIO,CIR

)


Channel Allocation

Allocation Principles

Impact on Established Call

Selection of optimum channel

The CIR

Estimation is

the basis of

Channel

Allocation !


Allocation Principles:

CIR > Soft block threshold of call; Will not Cause Established Call CIR degrade to unacceptable

level; Choose the channel with minimum influnce Minimum Established Call CIR degradation If CIR computed with a MAIO < soft block threshold ,then this

MAIO can’t be allocated for this channel; If all MAIO of a channel can’t be allocated, then this channe

l can’t be allocated for current call


Impact on Established call

The impact on established call is evaluated using CIR_DEC:Formula: CIR_DEC = CIRold – CIRnewCIRold: The estimate CIR of established call before channel allocationCIRnew: The estimate CIR of established call assuming channel allocated

If CIRnew < soft block threshold of established call, then MAIO used in computing CIRnew can’t allocated for this channelIf all MAIO can’t be allocated, this channel can’t be allocated for current call


Selection of optimum channel

CRES ＝ |CIRtgt － CIRest| ＋ MAX{CIR_DECi}CIRtgt ： Target CIR of newly arrived call(current call) ；CIRest ： Estimated CIR of current channel ；CIR_DECi ： CIR Degradation of established call ；

Select a (channel 、 MAIO) combination with the minimum CRES

Which channel

to be

chosen?

Minimum Discrepancy

between estimated

CIR and target CIR


Benifit

Improve the quality of network Enhance the CIR Reduce the inter interference No need to modify the hardware , just have to

update the software


Limitation

Need to be synchronous at air interface first of all Increase the computation of CPU If open the soft block threshold , the congestion

maybe increase Not suitable to the wide cover scene Conflict with Flex MAIO

HUAWEI TECHNOLOGIES CO., LTD.

www.huawei.com

Huawei Confidential

Security Level:

英文标题 :40-47pt

副标题 :26-30pt

字体颜色 : 反白内部使用字体 :

FrutigerNext LT Medium

外部使用字体 : Arial

中文标题 :35-47pt

字体 : 黑体副标题 :24-28pt

字体颜色 : 反白字体 : 细黑体

www.huawei.com

Thank you!


examples

Example 1 MA1={1,4,7,10},HSN1=0,MAIO1=0; MA2={1,4,7,10},HSN1=0,MAIO2=0; FN_OFFSET=0;

Co-channel Interference Probability = 100%


examples

Example 2 MA1={1,4,7,10},HSN1=0,MAIO1=0; MA2={2,5,8},HSN1=0,MAIO2=2; FN_OFFSET=0;

Ad-channel Interference Probability = 25%

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