Double opportunistic transmit relaying system with GSC for power saving in Rayleigh fading channel

Conventional opportunistic transmit (COT) relaying system does not consider the received SNR between R-D path. For that reason, it can't guarantee all the received SNRs exceed the threshold at destination. In this paper, we propose double opportunistic transmission relay (DOT) system which considers the received SNR both from S-R and R-D paths. It is noticed that the proposed system can be reduced to 6.9, 20.9, 32.4, and 41.4 % of power saving to that of COT relay system for K = 3, 5, 7, and 9, respectively at a given condition of P
_out
=1×10
^-3
and γ̅
_SR
/Γ = 30 dB. And the performance of DOT system is superior than that of COT system for the identical number of active transmit relays under the same condition of γ̅
_RD
/Γ
_RD
.