Proc. of ICC 2008
The combined MIMO with Adaptive Modulation and Coding (AMC) technology can provide high spectral efficiency and link robustness. Moreover, the diversity-multiplexing tradeoff of MIMO systems motivates the design of adaptive algorithms that switch between the two approaches to enhance performance. While most existing adaptive algorithms focus on physical layer, the QoS requirements of multimedia services are mainly parameters in link layer. Hence cross-layer analysis on the queuing behavior of MIMO-AMC systems is necessary, but remains open. In this paper, under the conditions of unsaturated traffic and finite-length buffer, we investigate the queuing characters of two representative categories of MIMO systems, namely the BLAST system and the space-time block coding (STBC) system.We successfully model the service processes of both STBC and BLAST coupled with AMC, which is the most challenging part of the queuing analysis. We observe a new tradeoff between diversity and multiplexing in terms of link layer packet loss rate and queuing delay, based on which we propose a cross-layer design of diversity-multiplexing switching scheme to optimize the QoS satisfaction of the MIMO-AMC systems.