Relay-aided opportunistic scheduling in wireless networks

One of the most promising approaches to boost the communication efficiency in wireless systems is the use of multiuser diversity (MUDiv), where the fading of channels is exploited. The mechanism of scheduling the user with the best channel condition is called opportunistic scheduling (OS). In this paper, we propose a novel OS algorithm in wireless networks that reduces the feedback load with the aid of relaying. It is called relay-aided opportunistic scheduling (RAOS). We consider two schemes: non-greedy RAOS and greedy RAOS. In the non-greedy RAOS schemes, we consider two scenario: non-persistent and p-persistent, where the persisting occurs when no feedback is received via a relay. The RAOS algorithm requires users to feedback their signal-to-noise ratios (SNRs) either directly to the access point (AP) or via a relay. Furthermore, We analyse the RAOS algorithm under slow Rayleigh fading assumption and derive the closed-form expressions for the feedback load as well as the spectral efficiency. The result shows that the RAOS algorithm provides 55% feedback load reduction compared with other scheduling algorithms.