A PHY-MAC Cross-Layer Protocol for Ad Hoc Networks with Multiple-Antenna Nodes

In this paper, we propose a physical (PHY) - medium access control (MAC) cross-layer protocol for ad hoc networks with antenna-array-equipped nodes that employ single-antenna transmission and multiple-antenna reception. Our protocol extends the progressive back-off algorithm (PBOA), proposed by Toumpis and Goldsmith, by integrating medium access and power control with optimum receive beamforming (ORB); hence it is named PBOA-ORB. The protocol performance is evaluated via simulations over a single-hop ad hoc network that is subject to a uniform traffic load. It is shown that PBOA-ORB significantly enhances both the aggregate throughput and the energy efficiency of PBOA by harnessing the interference suppression and array gains of receive beamforming. Specifically, for a small number of antennas compared to the number of nodes, the aggregate throughput increases linearly with the number of antennas while the average energy consumption per data packet decreases.