Mobility control for achieving optimal configuration in wireless sensor networks

Recent work in wireless sensor networks, or simply called WSNs, has drawn attention to the mobility capability of each node. In Stojmenovic and Lin (IEEE Trans Parallel Distrib Syst 12: 1023–1032, 2001), it is proved that the optimal positions of the relay nodes along a single active flow must lie entirely on the line between the source and destination with each node spaced evenly along such a line. Based on this, we propose two practical solutions to control the relay nodes in WSNs to approach their optimal positions in the local relative coordinate system. One uses one-hop neighbor information and the other one uses two-hop neighbor information. Basically, each relay node will approach the midpoint on the line composed of neighbors. For the latter control scheme, we also discuss its different implementation with outdated two-hop neighbor information (lagged by one-round neighbor information exchange and update). This is an improvement since given nodes only reuse the two-hop neighbor information previously saved at its one-hop neighbors and does not require any extra neighbor information collection. All the new methods prevent oscillations by demanding minimal moving distance per round (MDPR), otherwise the node does not move. Unlike the one presented in Goldenberg et al. (Proceedings of the 5th ACM International Symposium on Mobile Ad Hoc Networking and Computing (Mobihoc’04), pp 163–174 2004) using only one-hop neighbor information, our methods will converge more quickly. The experimental results show a substantial improvement on the speed of achieving the optimal configuration and the total moving distance of nodes.