Channel Aware Distributed Medium Access Control∗

Abstract—We investigate distributed channel-aware medium access control for wireless networks with arbitrary topologies and traffic distributions, where users can receive traffic from or send traffic to different users and different communication links may interfere with each other. We consider heterogeneous channels, where the random channel gains of different links may have different distributions. To resolve the network contention in a distributed way, each frame is divided into contention and transmission periods. The contention period is used to resolve conflicts while the transmission period is used to send payload in collision-free scenarios. We design a channel-aware Aloha scheme for the contention period to enable users with relatively better channel states to have higher probability of contention success while assuring fairness among all users. We show analytically that the proposed scheme completely resolves network contention and achieves throughput close to that using centralized schedulers. Besides, this scheme is also robust to any channel uncertainty. Simulation results demonstrate that the proposed scheme significantly improves network performance. The proposed random access approach can be applied to different wireless networks, such as cellular, sensor, and mobile ad hoc networks, to improve quality of service. Index Terms – channel aware, random access, distributed, scheduling, medium access control I