| Mobile ad hoc networking technology has received growing interest lately. Several applications can be envisioned for such networks ranging from disaster relief or battlefield communications to wireless home networking.; In mobile and wireless network environments where each host is free to move, availability of nodes' current position or expected future location may have a broad impact on applications. The main objective of this dissertation is to investigate several ways of using location information in mobile ad hoc networks. Essentially, this dissertation deals with three major issues— unicast routing protocol, geocasting protocol, and medium access protocol.; Design of efficient (unicast) routing protocols becomes a challenging problem in mobile ad hoc networks due to its unique characteristics, such as dynamic topology changes and bandwidth-constrained wireless links. This dissertation presents a new ad hoc routing protocol, called “Location-Aided Routing (LAR)”. In the proposed LAR protocol, location information of mobile hosts is utilized to achieve the goal of reducing routing-related overhead. The basic idea of LAR is that routing discovery overhead can be significantly decreased by limiting the search space for a desired route to a destination.; This dissertation also proposes the use of geocasting in mobile ad hoc networks. Geocasting, a variation of multicasting, is a mechanism to deliver messages of interest to all hosts within a specified geographical region. In this dissertation, several geocasting protocols based on flooding are developed. We refer to them as “Location-Based Geocasting”, since the geocast flood is limited to a small region based on location information. A different approach combining unicast and flooding, named “GeoTORA,” is also proposed. In GeoTORA, the TORA routing protocol is modified to be able to perform anycast and geocast.; Ad hoc network performance could be improved further by using directional antennas. However, to best utilize directional antennas, a suitable medium access control (MAC) protocol must be designed. Current MAC protocols, such as the IEEE 802.11, do not benefit when using directional antennas since these protocols have been designed for omnidirectional antennas. In this dissertation, novel MAC protocols suitable for ad hoc networks using directional antennas are presented. The proposed “Directional MAC” schemes can allow increased numbers of simultaneous transmissions, resulting in improved performance. |
