Ramis, Jaume; Femenias, Guillem (Mobile Communications Group, University of the Balearic Islands, Ctra. de Valldemossa Km. 7,5, Spain)
Cross-layer designs combining adaptive modulation and coding (AMC) with automatic repeat request (ARQ) have recently been widely explored. In addition, cooperative communication has attracted increased research attention as a promising technique for achieving diversity gain in wireless networks. In this paper a novel cross-layer analytical framework to jointly exploit the capabilities of cooperative-ARQ and AMC is proposed. The framework is based on a multidimensional discrete-time Markov chain (DTMC) queuing model. To exploit the joint impact on quality-of-service (QoS) performance measures of both AMC and cooperative-ARQ, a formulation of a cross-layer design as a constrained optimization problem is presented. Numerical results confirm the validity of the model and reveal that the proposed cooperative-ARQ protocol consistently outperforms the non-cooperative counterpart.