Low-Complexity Scheduling Policies for Achieving Throughput and Delay Optimality in Multi-Channel Wireless Networks

In this paper, we study the scheduling problem for downlink t ransmission in a multi-channel (e.g., OFDM-based) wireless network. We focus on a single cell, wit h the aim of developing a unifying framework for designing low-complexity scheduling policies tha t c n provide optimal performance in terms of both throughput and delay. We develop new easy-to-verify su ficient conditions for rate-function delay optimality (in the many-channel many-user asymptotic regi me) and throughput optimality, respectively. The sufficient conditions allow us to prove rate-function de lay optimality for a class of Oldest Packets First (OPF) policies and throughput optimality for a large class o f Maximum Weight in the Fluid limit (MWF) policies, respectively. By exploiting the special feature s of our carefully chosen sufficient conditions and intelligently combining policies from the classes of OPF an d MWF policies, we design hybrid policies that are both rate-function delay-optimal and throughputoptimal with a complexity ofO(n logn), wheren is the number of channels or users. Our approach yields signi fica tly lower complexity than the only previously known delay (rate-function) and throug hput optimal scheduling policy, which incurs a high complexity ofO(n). We also conduct numerical experiments to validate our theo retical results.