ABSTRACT
This chapter discusses the two major classes of adaptive scheduling techniques suitable for implementation in beyond 3G OFDMA-based cellular networks, namely, adaptive physical layer scheduling and adaptive cross-layer scheduling. It discusses the modifications that could be made in these scheduling techniques to be operable with limited channel knowledge in downlink resource scheduling. The margin adaptation and rate adaptation formulations of adaptive physical layer scheduling is explained with practical real-time scenarios. The chapter presents and compares several heuristic algorithms that can achieve near-optimal performance with less complexity. It describes adaptive cross-layer scheduling techniques with their two subclasses: delay-insensitive and delay-sensitive subclasses. For each subclass, the chapter illustrates several algorithms and provides a comparison of their performance. It illustrates some solutions to modify the presented scheduling algorithms for operation in limited channel knowledge, as in the case of downlink transmission in cellular networks. The chapter explains feedback mechanisms and describes the modifications required for each of them.
