Ad-hoc mobility management with randomized database groups

Zygmunt J. Haas, Ben Liang

Abstract: A distributed mobility management scheme using randomized database groups (RDG) is proposed and analyzed for ad-hoc networks. In the proposed scheme, location databases are stored in the network nodes, comprising a virtual backbone within the flat network architecture. Upon location update or call arrival, a mobile's location information is written to or read from, respectively, a group of randomly chosen databases. Compared with a centralized scheme (such as the home location register) with fixed associations, this scheme is more suitable for ad-hoc networks, where the connectivity of the nodes with the rest of the network can be intermittent and sporadic, and the databases are relatively unstable. The expected cost due to call loss and location updates using this scheme is analyzed in the presence of database disconnections. Based on the expected cost, we present the numerical determination and approximation of the optimal total location database number, the optimal database access group size, and the optimal location update frequency, under different network stability, traffic, and mobility conditions. Numerical results show that the RDG scheme provides an robust and efficient approach to ad-hoc mobility management.