The value of cooperation between relays in the multiple‐access channel with multiple relays
Boaz Ghelber, Ron Dabora · Transactions on Emerging Telecommunications Technologies · 2012
ABSTRACT We study the discrete memoryless multiple‐access channel with two independent sources, two relays and a single destination. We refer to this configuration as the multiple‐access channel with multiple relays (MACMRs), which is a generalisation of the multiple‐access relay channel model obtained by adding a relay node. We present inner and outer bounds on the capacity region of the MACMR. The inner bound is based on a hierarchical decode‐and‐forward scheme, in which each relay decodes the messages of the lower hierarchy. We extend the regular encoding, sliding‐window decoding and backward decoding techniques, previously applied to multiple‐access relay channels and multiple‐relay channels, to MACMRs. The outer bounds are obtained using the cut‐set bound. For Gaussian MACMRs, the bounds are evaluated and compared with those obtained for the multiple‐access channel with parallel relays. We conclude that a significantimprovement in performance can be obtained by letting the relays interact with each other. Copyright © 2012 John Wiley & Sons, Ltd.