Adaptive-Rate Transmission With Opportunistic Scheduling in Wireless Networks.

In this paper, we propose an adaptive-rate transmission scheme with opportunistic scheduling in a two-hop relay network over a Rayleigh fading environment. We assume that only channel state information (CSI) at receivers is available in a decentralized network, where n source-to-destination pairs are completely independent and m half-duplex relays cooperate by exchanging their selected source IDs at the beginning of the two-hop transmission. In the limit of large n and fixed m, the system throughput of the scheme scales as (m/ \2)\log\, \log\, n. It is shown that this is the same achievable scaling even with perfect CSI assumptions at transmitters and full cooperation among nodes. Furthermore, it is shown that the optimal scaling of m is \Theta(\log\, n), under which a linear increase in throughput with m is obtained. A closed-form delay expression of the proposed scheme is also presented. [ABSTRACT FROM PUBLISHER]