MAC/PHY Cross-Layer Design of MIMO Ad Hoc Networks with Layered Multiuser Detection

In this paper, we present a novel MAC approach for ad hoc networks in which Multiple Input-Multiple Output (MIMO) techniques are used at the physical level (PHY). The use of MIMO in PHY point-to-point as well as multiuser communications has been extensively studied in the recent literature. Here we go one step further, extending the approach to also include protocol design for decentralized and infrastructureless ad hoc networks. First, we study the impact of MIMO on packet transmission in an ad hoc network setting. Then, following a crossiquestlayer design paradigm, we deploy a distributed access control protocol and characterize its performance, with the aim to improve spatial reuse and convey more information on a single ad hoc link. We also explore the interaction between the Medium Access Control (MAC) and PHY layers, and use this knowledge to implement proper policies for distributed traffic control and robustness against interference. Important tradeoffs that arise when managing radio resources are highlighted, and extensive simulation results are presented and discussed.