A Unified MAC Layer Framework for Ad-Hoc Networks With Smart Antennas

Abstract

Smart antennas represent a broad variety of antennas that differ in their performance and transceiver complexity. The superior capabilities of smart antennas, however, can be leveraged only through appropriately designed higher layer network protocols, including at the medium access control (MAC) layer. Although several related works have considered such tailored protocols, they do so in the context of specific antenna technologies. In this paper, we explore the possibility for a unified approach to medium access control in ad hoc networks with smart antennas. We first present a unified representation of the PHY layer capabilities of the different types of smart antennas, and their relevance to MAC layer design. We then define a unified MAC problem formulation, and derive unified MAC algorithms (both centralized and distributed) from the formulation. Finally, using the algorithms developed, we investigate the relative performance trade-offs of the different technologies under varying network conditions. We also analyze theoretically the performance bounds of the different smart antenna technologies when the available gains are exploited for rate increase and communication range increase.