Cross-layer scheduling with prescribed QoS guarantees in adaptive wireless networks

Providing guaranteed quality-of-service (QoS) for multimedia applications over wireless fading channels is challenging. To this end, we develop a cross-layer design for multiuser scheduling at the data link layer, with each user employing adaptive modulation and coding (AMC) at the physical layer. By classifying users into: QoS-guaranteed and best-effort users, the proposed scheduler enables prescribed QoS guarantees and efficient bandwidth utilization simultaneously. Furthermore, our cross-layer scheduler enjoys low-complexity implementation and analysis, provides service isolation and scalability, decouples delay from dynamically-scheduled bandwidth, and is backward compatible with existing separate-layer designs. Accuracy of the performance analysis is verified by simulations and pertinent robustness issues are briefly discussed. Numerical examples illustrate the steady-state statistical performance for a single and multiple users, as well as the asymptotic behavior for a large number of users.