Design and analysis of location management schemes for a new light-weight wireless network

Abstract

With the advances in low-cost wireless networking products, researchers and providers are looking at various alternate approaches to mobile communications that can provide low-cost services, and are easy to set up. These approaches are to coexist with traditional Cellular Networks. To this end, we propose a novel light-weight mobile communication network architecture called Cell-Hopping. Cell-hopping has only base stations interconnected by wireless inter-basestation links (WIBLs) as the network infrastructure. WIBLs support all routing and switching in cell-hopping networks, obviating the need for costly core networks. However, lack of core networks make location management more challenging because: (i) location databases cannot be maintained in the core, (ii) database update consumes precious wireless resource, (iii) signalling can not be supported by the core (no core) among disjoint segments of the network. Consequently, approaches which minimise or eliminate database updates are more suitable for Cell-hopping networks. We provide a primary scheme for location management in Cell-hopping and analytically show the scalability problem. To address the scalability problem, we propose a location caching scheme to be used with the primary scheme. In the caching scheme, tuning the cache timer value is most crucial for the success of the scheme because the timer is the most important control parameter. We present analysis of the location caching scheme, and provide a closed-form expression for the optimum timer value for the location cache entry based on user mobility parameter. Using numerical examples, we show that the signalling cost can be reduced by as much as 80% for reasonable message-to-mobility (MMR) values. Conversely, incorrectly selected timer values can nullify benefits of using the location caching scheme.