Mobile Ad Hoc Networks Exploiting Multi-Beam Antennas

This chapter introduces the concept of multi-beam antenna (MBA) in mobile ad hoc networks and the recent advances in the research relevant to this topic. MBAs have been proposed to achieve concurrent communications with multiple neighboring nodes while they inherit the advantages of directional antennas, such as the high directivity and antenna gain. MBAs can be implemented in the forms of multiple fixed-beam directional antennas (MFBAs) and multi-channel smart antennas (MCSAs). The former either uses multiple predefined beams or selects multiple directional antennas and thus is relatively simple; the latter uses smart antenna techniques to dynamically form multiple adaptive beams and thereby provides more robust communication links to the neighboring nodes. The emphases of this chapter lie in the offerings and implementation techniques of MBAs, random-access scheduling for the contention resolution, effect of multipath propagation, and node throughput evaluation.