
14 Energy-Efficient Cooperative Wireless Communication and Networks
link can be shown as
I
s,d
=
⎧
⎪
⎨
⎪
⎩
1
2
log(1 + 2p|a
s,d
|
2
), |a
s,r
|
2
<f(p),
1
2
log(1 + p|a
s,d
|
2
+ p|a
r,d
|
2
), |a
s,r
|
2
≥ f (p),
(2.8)
where
p is the normalized transmission power for both source and relay. It
is worth noting that the same noise variance is assumed at both relay and
destination. Therefore, the outage event is given by
I
s,d
<band the outage
probability becomes
out
= Pr[I
s,d
<b]
= Pr[|a
s,r
|
2
<f(p)]Pr[2|a
s,d
|
2
<f(p)]
+ Pr[|a
s,r
|
2
≥ f (p)]Pr[|a
s,d
|
2
+ |a
r,d
|
2
<f(p)] . (2.9)
By computing the limit, we obtain from (2.9)
1
f
2
(p)
out
=
1
f(p)
Pr[|a
s,r
|
2
<f(p)]
T1
1
f(p)
Pr[2|a
s,d
|
2
<f(p)]
T2
+ Pr[|a
s,r ...