Non-cooperative wireless orthogonal multiple access schemes with and without relaying

In this paper, we study the performance of non-cooperative wireless multiple access systems with noisy separated channels, where correlated sources communicate to an access point (AP) directly or, possibly, by using a relay. In particular: if no relay is used, then the sources may make use of channel coding; if the relay is used, then the sources transmit uncoded information and the relay may add redundancy (i.e., parity bits). In all cases (coded and uncoded, with and without relay), scenarios with block-faded links are considered. Our goal is to explore the potential benefits which can be obtained when source correlation is exploited at the AP. In uncoded communication scenarios (without relay), we quantify the improvement, with respect to distributed source coding (DSC) schemes, of the proposed schemes. In coded scenarios, we consider the use of low-density parity-check (LDPC) codes, and compare different systems (with and without relay) by keeping fixed the overall coding rate.