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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
Interference Based Channel
Allocation
HUAWEI TECHNOLOGIES CO., LTD. Page 2Huawei Confidential
Overview Mechanism Benefit Limitation
HUAWEI TECHNOLOGIES CO., LTD. Page 3Huawei Confidential
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
HUAWEI TECHNOLOGIES CO., LTD. Page 4Huawei Confidential
Overview Mechanism Benefit Limitation
HUAWEI TECHNOLOGIES CO., LTD. Page 5Huawei Confidential
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…
HUAWEI TECHNOLOGIES CO., LTD. Page 6Huawei Confidential
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 !
HUAWEI TECHNOLOGIES CO., LTD. Page 7Huawei Confidential
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
HUAWEI TECHNOLOGIES CO., LTD. Page 8Huawei Confidential
Interference Probability Calculation
Input: Moblie Allocation, MAIO, HSN, FrameNumber Offset
Output : Interference Probability
Interfere
nce
Probabili
ty=100%
Interfere
nce
Probabili
ty=0%
example
HUAWEI TECHNOLOGIES CO., LTD. Page 9Huawei Confidential
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
HUAWEI TECHNOLOGIES CO., LTD. Page 10Huawei Confidential
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
HUAWEI TECHNOLOGIES CO., LTD. Page 11Huawei Confidential
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
HUAWEI TECHNOLOGIES CO., LTD. Page 12Huawei Confidential
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
)
HUAWEI TECHNOLOGIES CO., LTD. Page 13Huawei Confidential
Channel Allocation
Allocation Principles
Impact on Established Call
Selection of optimum channel
The CIR
Estimation is
the basis of
Channel
Allocation !
HUAWEI TECHNOLOGIES CO., LTD. Page 14Huawei Confidential
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
HUAWEI TECHNOLOGIES CO., LTD. Page 15Huawei Confidential
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
HUAWEI TECHNOLOGIES CO., LTD. Page 16Huawei Confidential
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
HUAWEI TECHNOLOGIES CO., LTD. Page 17Huawei Confidential
Overview Mechanism Benefit Limitation
HUAWEI TECHNOLOGIES CO., LTD. Page 18Huawei Confidential
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
HUAWEI TECHNOLOGIES CO., LTD. Page 19Huawei Confidential
Overview Mechanism Benefit Limitation
HUAWEI TECHNOLOGIES CO., LTD. Page 20Huawei Confidential
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!
HUAWEI TECHNOLOGIES CO., LTD. Page 22Huawei Confidential
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%
HUAWEI TECHNOLOGIES CO., LTD. Page 23Huawei Confidential
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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