Mobility-aware topology control in mobile ad hoc networks

Abstract

This paper proposes two topology control algorithms – ABsolute Distance-based (ABD) and PRedictive Distance-based (PRD), which adjust the transmission range of individual nodes in a MANET to achieve good network throughput, particularly under correlated node movements as in a vehicular environment. Both algorithms attempt to maintain the number of logical neighbors between two predefined thresholds. The ABD algorithm uses the absolute distance as the neighbor selection criteria while the PRD algorithm incorporates mobility information to extend the neighbor lifetime, and hence a less chance of broken links. A simple expression of saturated end-to-end throughput is presented as a function of path availability which depends on the average transmission range, the network connectivity, and the probability of broken links. Based on the simulation results, it was found out the transmission range can only be increased to a certain value to prolong the next-hop neighbor. Beyond such value, the MAC interference becomes a more dominant factor over the end-to-end throughput than routing overheads or the effects of broken links. Consequently, using a higher transmission range will only decrease the throughput. Under Street mobility which has correlated node movement, PRD algorithm can take advantage of such correlation and achieves higher path availability and end-to-end throughput than ABD algorithm.