Because of the heterogeneity in radio transceiver capabilities and influence of surroundings, unidirectional links arise in wireless mobile ad-hoc networks. Since most of existing routing protocols for MANETs assume that all links are bidirectional, they would fail in establishing a path or cannot prepare sufficient number of paths for the purpose of multipath routing in a network with unidirectional links. In this paper, based on an ant-based routing algorithm, we propose a routing protocol which uses unidirectional links for establishing paths to improve the connectivity of networks and take advantage of multipath routing strategy. However, using unidirectional links introduces new problems such as detection of link disconnection. In order to solve these problems, we propose three mechanisms; de- touring around a unidirectional link, detecting link failures by ants, and blind retransmission. Simulation experiments showed that the connectivity increased and more packets could be delivered than AODV and AntHocNet which did not use unidirectional links. It was also shown that the path establishment delay was shorter and the load of control packets per data packet was lower than AntHocNet.
['Taro Maekawa', 'Harumasa Tada', 'Naoki Wakamiya', 'Makoto Imase', 'Masayuki Murata']
An Ant-based Routing Protocol using Unidirectional Links for Heterogeneous Mobile Ad-Hoc Networks