Integrating retransmission diversity with real-time scheduling over wireless links

In this paper, cross-layer combining of an adaptive modulation-coding (AMC) scheme at the physical layer and the use of automatic repeat request (ARQ) retransmissions at the medium access control (MAC) layer is integrated into the design of scheduling for multi-user wireless networks. A class of scheduling algorithms capable of jointly collecting retransmission diversity and multi-user diversity are developed for delay sensitive real-time network traffic. Numerical computer simulations are provided to examine the merits of our novel schemes for multiple real-time transmissions over Nakagami block fading channels. Analytical and simulation results show that the proposed scheduling schemes can asymptotically guarantee the prescribed fairness and average delay requirements for real-time traffic, even when the underlying fading channel distribution is unknown a priori.