Exploiting smart antennas in wireless mesh networks using contention access

Smart antennas can increase the capacity of mesh networks and reduce the susceptibility of individual nodes to interception and jamming, but creating the conditions that allow them to be effective is difficult. In this article we provide a broad review of antenna technologies and identify their capabilities and limitations. We review mechanisms used by medium access control schemes to arbitrate access. These reviews let us identify a small set of conditions that are necessary for smart antenna exploitation. We then review the most common MAC approaches, carrier sense multiple access, slotted aloha, and time-division multiple access, and evaluate their suitability for exploiting smart antennas. We demonstrate that they are not capable of creating the complete set of antenna exploitation conditions while retaining a contention nature. We follow with a discussion of the synchronous collision resolution (SCR) MAC scheme and describe how it creates all the exploitation conditions. We conclude that SCR provides the best support for smart antenna exploitation with the added benefits that there is no requirement for all nodes to be equipped with the same antenna technologies and that smart antennas can be combined with channelization technologies to provide even higher capacities