Pricing and Power Control in a Multicell Wireless Data Network Po Yu Chen October, 2001 IEEE Journal...
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Transcript of Pricing and Power Control in a Multicell Wireless Data Network Po Yu Chen October, 2001 IEEE Journal...
Pricing and Power Control in a Multicell Wireless Data Network
Po Yu ChenOctober, 2001
IEEE Journal on Select Areas in Communications
Prolog The data services in wireless
networks necessitate efficient and efficiency radio resource management
Power control is important in CDMA system
Introduction (1/2) Why using power control ?
To provide each signal with adequate quality without causing unnecessary interference to other signals
To minimize the battery drain in portable terminals
Introduction (2/2)
Paper Concept Extend reference [5] (single-cell
environment) to multi-cell environment Power control for data network under a
new light, powered by mathematics and concepts from microeconomics
Pricing scheme to improve utility with respect to both the transmit power and BS assignment
Key word Utility function: measure performance in
bits per joule (bits/joule) Nash equilibrium: no user has any incentive
to change its power level since no individual improvement in utilities is possible
Non-cooperative game: terminals operating independently to achieve best performance (a distributed power control algorithm )
Cooperative game: a centralized power control algorithm
Functions SIR
Utility function: 包含了 SIR和 power control的訊息
N
jkkkik
jijij
ph
ph
R
W
,1
2
Joulebits
p
f
M
RLPu
j
ja
jaj
j
)()(
hij: path gain
pj: power of user j
W: bandwidth
R: data rate
L/M: code rate , f(.):能成功被接收的機率
BS Assignment Based on MRSS (1/2) MRSS (Max. Received Signal Strength)
aj:被 assigned給 j的 BS hij:path gain dij:distance between terminal and BS
N j all for d h aiji
iji
j min arg max arg
BS Assignment Based on MRSS (2/2) 固定了 BS assignment的方法,所以只剩下 power control的變數
Multi-cell power control game (MCPG)
P-j: interference power vector, but not include pj
)()(max ,, jjjajjjPp
ppuppuj
jj
BS Assignment Based on MSIR (1/2) Generalize the MRSS ,將 BS assignm
ent也考慮進來。 方法:將有最大 SIR值的 BS assign給 t
erminal 所以在這裡 BS assignment也變成了一個變數
BS Assignment Based on MSIR (2/2) MCPG的 utility function (two dimension)
簡化問題,分成兩項討論:
先解決 BS assignment的問題( MAX SIR )再處理 power control的問題
Njallforppu jjjaap jjj
)(max ,,
)(maxmax)(max ,,,
jjjaap
jjjaap
ppuppuj
jjj
jj
Pricing (1/2) Define: every transmit power has pricing 加入 pricing後的結果: new utility function
ci:the pricing factor announced by BS
Alpha is a scalar, Ni is the number of the terminals assigned to BS
jajja pcpuj
)(,
ii Nc
Pricing (2/2) Pricing分為兩種:
--Global Pricing
--Local Pricing ci is based on the amount of traffic tha
t is offered in its service area
cconstsomeforiallforcci .
Power control game with Pricing
For MCPG-MRSS
For MCPG-MSIR
jajjjjaPp
pcppuj
jj
)(max ,
Njallforpcppu jajjjjaap jjj
)(max ,,
Best equal-SIR Good for MCPG (no pricing, the same SI
R) dependent on local information A centralized scheme,由 BS來計算 Term
inal的 SIR BS need to announce the best SIR The terminal needs to be applied an SIR
balancing algorithm
System Model Multi-cell CDMA data system N=28 terminals K=4 base stations Frame size is fixed No forward error correction Simple path loss
4ij
ij d
Ch
Conclusion 此篇利用microeconomics的 concept和mathematics來引導結果—證明加入pricing scheme有助於效能提升
傳 data和傳 Voice的方法不同,所以MRSS不能夠保證 data的 QoS ,因為 power最大並不代表 SIR就大。