Distributed STBC with relay subset selection for single carrier relay-assisted transmissions

This paper investigates the coding gain achieved between the best relay and the relay subset selection in a two-hop wireless network with relay-assisted transmission. Both best relay and relay subset selection achieves the maximum diversity, but the later becomes a better alternative in certain scenarios. First in low mobility scenarios, when the channel fading remains static for longer duration and this could result in an unfair usage of the same (best) relay terminal for an extended period of time. Second, when there is a power constraint which limits the maximum transmit power at the relay terminals. We have presented a simple technique for calculating the pairwise error probability (PEP) upper bound for distributed time-reversal space-time block code (D-TR-STBC) with best relay and relay subset selection, which offers an easy way of quantifying the coding gain achieved. Results from the numerical simulation of error probabilities are given to corroborate our analysis.