On the Performance of Access Strategies for MIMO Ad Hoc Networks

In this paper, we address the impact of different access strategies in ad hoc networks with multiple antennas and MIMO communications. We employ a cross–layer designed MAC protocol that allows both for multiple simultaneous access to the radio medium and for proper exploitation of multiuser detection at the receiver for interference cancellation purposes. Still, the network is subject to early deadlock if no access strategy is employed that reduces transmission persistency. To this aim, we study two types of exponential backoff, namely node– wise and destination–wise, and combine them with a form of cooperative agreement on who takes the role of transmitter or receiver. The impact of all schemes is assessed and a comparison is pursued, focusing on typical network metrics (such as throughput and transmission delay among others) and showing when and why one technique performs better than the others.