RODA: a new dynamic routing protocol using dual paths to support asymmetric links in mobile ad hoc networks

The existing routing protocols in mobile ad hoc networks assume that all the nodes have the same transmission range. In other words, the mobile ad hoc network has only symmetric links, which means that two neighboring nodes A and B are within the transmission range of one another. However, since nodes consume battery power independently according to their computing and communication load, there exist asymmetric links, which means that node A is within node B's transmission range, but not vice versa. In this paper, to cope with asymmetric links, a new routing protocol based on source-initiated on-demand routing (called RODA-routing protocol with dual paths to support asymmetric links) is presented. In order to perform route maintenance in an efficient manner, dual paths-forward (source to receiver) and backward (receiver to source) paths-are used to send and receive data packets. In addition, a timer mechanism is introduced to deal with simultaneous and consecutive broken links on both forward and backward paths. Simulation results reveal that RODA copes well with an ad hoc network having asymmetric wireless links under the presence of mobility.