On Cognitive Radio Networks with Opportunistic
Power Control Strategies in Fading Channels
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, VOL. 7, NO. 7, JULY 2008
指導老師:王瑞騰 老師
學生:盧俊傑
Outline
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INTRODUCTION
SYSTEM MODEL
OPPORTUNISTIC POWER CONTROL
STRATEGY
THE IMPACT OF IMPERFECT CHANNEL
ESTIMATION
NUMERICAL RESULTS
CONCLUSION
INTRODUCTION
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we consider a cognitive radio system in fading
wireless channels and propose an opportunistic
power control strategy for the cognitive users.
The achievable rate of a cognitive user under the
proposed power control strategy is analyzed and
simulated, taking into account the impact of
imperfect channel estimation.
SYSTEM MODEL
Primary
transmitter
ZP
Primary
1) Self-goal: Trying to transmit as
receiver
YP
XP
f
g
YC
XC
Cognitive
transmitter
ZC
Cognitive
receiver
much information for
himself as possible.
2) Moral-goal: Maintaining the
primary user’s outage probability
unaffected.
: Rayleigh fading
: Rayleigh fading
: Rayleigh fading
: Rayleigh fading
: white Gaussian noise
: white Gaussian noise
Primary
transmitter
ZP
Primary
receiver
YP
XP
f
g
YC
XC
Cognitive
transmitter
ZC
Cognitive
receiver
OPPORTUNISTIC POWER CONTROL STRATEGY
1
0
-b
1
0
-b
THE IMPACT OF IMPERFECT CHANNEL ESTIMATION
1
1
0
0
-b
-b
1
0
-b
1
0
-b
NUMERICAL RESULTS
The maximum transmit power
of the cognitive user
The maximum transmit power
of the primary user
CONCLUSION
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The opportunistic power control strategy for the cognitive user, which
has been proved to be optimal in the sense that it maximizes the
achievable rate of cognitive user while guaranteeing the outage
probability of the primary user not to be degraded.
The simulation results verify its effectiveness in enhancing the
robustness of our strategy.