Performance Evaluation of MANETs Using Smart Antennas in Multipath Fading Environment

This paper investigates the performance of a MANET where nodes are equipped with fully adaptive smart antennas. The physical antenna system is a uniform circular array and the signal processing unit, employing LMS algorithm, uses a reference signal to update the antenna weights. A comparison between a MAC protocol called Selective CSMA with Cooperative Nulling (SCSMA/CN) and 802.11 DCF shows that higher throughput can be obtained exploiting efficient SDMA schemes. The objective of this paper is to extend, via simulations, the considerations on interferer suppression capabilities of smart antennas in more severe channel conditions. So, the link model takes into account path loss, cochannel interference and multipath fading, using a modified Jakes model. Simulation results show the performance degradation due to increase of angular spread in multipath channels due to difficulties of smart antennas in placing nulls towards undesired directions. Moreover, this paper puts into evidence the effects of fading on network throughput in mobility scenario