Queuing with Adaptive Modulation over MIMO Wireless Links for Deadline Constrained Traffic: Cross-Layer Analysis and Design

In this paper, we consider a deadline constrained traffic and analyze the joint effects of packet queuing and adaptive modulation (AM) for packet transmission in MIMO systems. We present a general analytical procedure, and derive the achievable delay-bound violation probability, the packet loss rate, and the average throughput of AM in MIMO wireless links employing orthogonal space time block coding (STBC) over Nakagami fading channels. In the proposed analytical procedure, we use statistical delay-bound for deadline constrained traffic based on the effective bandwidth theory. Based on our performance analysis, we propose a cross-layer design, which selects the optimal target packet error rate of AM at the physical layer, to minimize the packet loss rate and maximize the average throughput, when combined with packet queuing at the data link layer. Numerical results demonstrate that the system performance depends on various parameters, and show the performance gain due to cross-layer design. We also discuss briefly possible applications of our proposed modeling to quality of service guarantee in multiuser scenarios.