Exploiting Dynamic Relays with Limited Overhead in Cellular Systems

Cooperative diversity has been shown to greatly improve performance of wireless networks. The utilization of dynamic relays (cell users acting as relays) in cellular systems is of particular importance as cooperative diversity can be leveraged without the addition of costly infrastructure. However this poses significant challenges to the system design related to signaling load and complexity for relay selection. The related signaling overhead and complexity are proportional to the number of relay candidates per target user; therefore it is desirable that this number of candidates is reduced without compromising the performance gains brought by relaying. In this paper the relaying patterns in a cell are observed (which users relay as a function of their position). A novel algorithm is devised exploiting the observed relaying patterns as well as attenuation information and it is shown to achieve high overhead reduction; it greatly limits the number of relay candidates per target user and thus reduces feedback overhead. This leads to minimal performance compromise while signaling load and complexity, related to cooperative diversity through dynamic relays, remain affordable.