From: Performance analysis of relay selection in cooperative networks over Rayleigh flat fading channels
T 11
T 12
T 21
T 22
S1
T x 1
–
S2
T x 2
Rb0
R x 1
R x 2
T x ~ 1
T − x ~ 2 ∗
Rb1
T x ~ 2
T x ~ 1 ∗
D
R T 22 (DS)
R T 23 (DS)