Recent advances in IEEE 802.11 (Wi-Fi) standards have led to unprecedented opportunities for commercial success and low pricing in wireless networking. Wireless access points that are easy to setup, use, and maintain, have become a household commodity. Inspired by the added benefit of their operation in the unlicensed frequency band, many home and small business owners are installing these commodity access points to quickly set up a high speed local wireless network within their premises. As this trend continues to grow, we will soon end up with a wide coverage of independent commodity access points in residential or commercial areas serving individual premises. Although these access points serve their intended purpose of networking indoor devices, they themselves do not provide any wide area communication services to mobile users. This monograph proposes a solution towards building a high-speed wide area wireless communication network by interconnecting densely deployed commodity access points. By cooperating with each other, these access points collectively form a widely distributed and self-organising wireless mesh network called Cell-Hopping. Such networks are different from traditional cellular networks in that they are not owned by a single entity and there is no wired switching infrastructure. User data hop through many wireless access points until they reach the intended recipients (hence the name Cell-Hopping). Cell-Hopping therefore can provide a low cost alternative to high-speed wide area wireless communications in many parts of our cities where dense deployment of wireless access point is expected. The monograph highlights many challenges, such as dynamic frequency management among neighbouring access points, billing and charging in a distributed mesh network with potentially hundreds of individual owners and operators, security, and routing, that must be resolved before Cell-Hopping can be realised. One of the most challenging issues is how to locate a user in such a network. Existing approaches to location management cannot be applied because Cell-Hopping networks do not have any central core infrastructure to host and manage location servers. To address this challenge, an on-demand location management framework has been proposed that requires each individual access point to maintain a small dynamic list only for the devices that are within the wireless coverage of that access point. The mesh network is queried to discover device locations. Using the on-demand location management framework, several query and location discovery schemes of increasing complexity and performance are proposed. Performance analysis of these schemes is accomplished using mathematical modeling and later validated with discrete-event computer simulation.
['Jahan Hassan']
Cell-Hopping: A New Architecture for Wireless Communications