Optimization of Jitter Configuration for Reactive Route Discovery in Wireless Mesh Networks

Jitter is a small, random variation of timing before message emission that is widely used in non-synchronized wireless communication. It is employed to avoid collisions caused by simultaneous transmissions by adjacent nodes over the same channel. In reactive (on-demand) routing protocols, such as AODV and LOADng, it is recommended to use jitter during the flooding of Route Request messages. This paper analyzes the cost of jitter mechanisms in route discovery of on-demand routing protocols, and examines the drawbacks of the standard and commonly used uniformly distributed jitter. The main studied drawback is denominated delay inversion effect. Two variations on the jitter mechanism --window jitter and adaptive jitter-- are proposed to address this effect, which take the presence and the quality of traversed links into consideration to determine the per-hop forwarding delay. These variations allow to effectively reduce the routing overhead, and increase the quality of the computed paths with respect to the standard uniform jitter mechanism. Simulations are also performed to compare the performance of different jitter settings in various network scenarios