Adaptive rate transmission with opportunistic scheduling in wireless networks

In this paper, we study the adaptive rate transmission with opportunistic scheduling in two-hop relaying networks, in which only channel state information (CSI) at receivers are available. Previous work [5] that proposed an opportunistic relaying scheme has focused on the fixed rate transmission. We develop an adaptive rate transmission scheme according to instantaneous channel connections. The scheme operates with cooperative relays and opportunistic scheduling for adaptive rate transmission, to improve the throughput performance. We obtain the exact throughput expression and we show that the advantage using adaptive rate transmission over fixed rate transmission is the multiplicative factor of log log n, where n is the number of users. Furthermore, we prove that the throughput achieved by the adaptive rate transmission scheme is actually the optimal throughput for two-hop relaying networks. Numerical results are presented, indicating the alignment with our theoretical analysis.