A location update scheme using multi-hop pointer forwarding in low-rate wireless mesh networks

Recently, a pointer forwarding scheme (PFS) was proposed to reduce location update overhead in wireless mesh networks. Using the PFS, location update is replaced with a simple forwarding pointer setup between two neighboring MRs until the forwarding chain K is less than or equal to the configurable parameter K_max for each MC. However, in PFS, if the two MRs are not one hop neighbors, the PFS fails to set up a forwarding pointer, and a location update event must be triggered, increasing location update overhead. To improve PFS, we present a novel location update scheme called a multi-hop pointer forwarding scheme (MPFS). The MPFS allows forwarding pointers to be constructed over multi-hop at once even if MRs are not one hop neighbor with each other. The key to achieving this lies in the logical tree distance constructed during network formation. The tree distance is used to relay forwarding pointer packets over multi-hop links without additional control overhead and to estimate hop distance between two MRs. By doing so, the MPFS improves the probability of success in forwarding pointer setup while ensuring K ≤ K_max, resulting in lowering the location update overhead. To evaluate our scheme we implement both the PFS and the MPFS in ns-2 and compare them. As a result, we show that the MPFS significantly reduces the number of location update events, resulting in reduction of location update delay and signaling overhead, and packet losses during location updates.