Distributed auto-configuration of neighboring cell graphs in radio access networks

In order to execute a handover processes in a GSM or UMTS Radio Access Network, each cell has a list of neighbors to which such handovers may be made. Today, these lists are statically configured during network planning, which does not allow for dynamic adaptation of the network to changes and unexpected events such as a cell failure. This paper advocates an autonomic, decentralized approach to dynamically configure neighboring cell lists. The main contribution of this work is a novel protocol, called DOC, which detects and continuously tracks the coverage overlaps among cells. The protocol executes on a spanning tree where the nodes are radio base stations and the links represent communication channels. Over this tree, nodes periodically exchange information about terminals that are in their respective coverage area. Bloom filters are used for efficient representations of terminal sets and efficient set operations. The protocol aggregates Bloom filters to reduce the communication overhead and also for routing messages along the tree. Using simulation, we study the system in steady state, when a base station is added or a base station fails, and also during the initialization phase where the system self-configures.