Using switched beam smart antennas in wireless Ad Hoc networks with angular MAC protocol

In this paper, a new medium access protocol, Angular MAC (AN-MAC), is proposed for enhancing the performance of Ad Hoc Wireless Local Area Networks (WLANs) by the use of smart antennas. In order to apply beam forming with smart antennas, the location of the receiver needs to be correctly determined. In this paper, we are proposing a Direction Finding (DF) algorithm through which, stations exchange modified RTS/CTS messages for training with each other to determine their respective locations and at the same time establish the links between nodes. With the help of the angular RTS/CTS messages, a medium access table is constructed to track the locations of not only the destination nodes but also all communicating neighbors. With this feature, our protocol enables angular CSMA and Space Division Multiple Access. The protocol also uses only directional beams to guarantee range extension. In this paper, the performance of the protocol is evaluated and compared with omni, regular 802.11 WLANs.