PCS network survivability

Research and development on the survivability of networks has largely focused on public switched telecommunications networks and high speed data networks with little attention on the survivability of wireless access networks supporting cellular and PCS communications. This paper provides an overview of the survivability issues in PCS networks with emphasis on the unique difficulties presented by user mobility and the wireless channel environment. A multi-layer framework for the study of PCS network survivability is proposed. Metrics for quantifying network survivability are identified at each layer. It is shown that user mobility significantly worsens the network performance after even small failures, as disconnected users move among adjacent cells and attempt to reconnect to the network. Thus survivability strategies must be designed to contend with spatial as well as temporal network behavior. Possible survivability strategies and restoration techniques for each layer in the framework are also discussed.