Angular MAC protocol with location based scheduling for wireless ad hoc networks

Smart antenna systems not only enable users to have high quality links but also increase network throughput by allowing spatial reuse of wireless channels by the use of directional transmission. The performance of smart antenna systems is limited because of the increased hidden terminal problem and deafness of nodes. We have proposed angular MAC (ANMAC) protocol that avoids both problems through medium access tables in the nodes that keep track of the locations of the destination nodes as well as all communicating neighbors. With this feature, angular CSMA and space division multiple access (SDMA) are achieved. In this paper, we present detailed performance analysis of ANMAC considering different topologies and traffic scenarios, and we show that SDMA cannot be fully exploited without a smart scheduler. We propose ANMAC with location based scheduling (ANMAC-LS) and compare its performance with other smart antenna approaches and omni 802.11 MAC. We prove the efficiency of location based scheduling in wireless networks with smart antennas, and we also show the effects of antenna orientation on throughput, using realistic antenna patterns and ANMAC protocol.