Channel-aware MAC performance of AMC-ARQ-based wireless systems

This paper proposes a novel framework for the cross-layer design and optimization of wireless networks combining adaptive modulation and coding (AMC) at the physical (PHY) layer with automatic repeat request and channel-aware multiuser scheduling protocols at the data link control (DLC) layer. The proposed framework is based on the use of first-order two-dimensional discrete timeMarkov chains (DTMCs) jointly modeling the AMC scheme and the amplitude and rate of change of the wireless channel fading envelope. The behavior of the scheduler is embedded into the multidimensional PHY layer Markov model through the use of a service-vacation process. Using this PHY-media access control (MAC) Markov model, the quality of service performance at the DLC layer is discussed considering two different approaches. The first one relies on an analytical framework that is based on the multidimensional DTMC jointly describing the statistical behavior of the arrival process, the queuing system, and the PHY layer. The second one is rooted in the use of the effective bandwidth theory to model the packet arrival process and the effective capacity theory to model the PHY/MAC behavior. Both the DTMC-based and effective bandwidth/capacity-based approaches are analyzed and compared in a cross-layer design aiming at maximizing the average throughput of the system where constraints on the maximum tolerable average packet loss and delay are to be fulfilled.