TABLE OF CONTENTS Cellular networks are the major platform for wireless location-based services (LBS). This is natural considering the widespread distribution of cellular handsets among a large part of the world's population. Position accuracy demands and the methods used for positioning are highly dependent on the nature of these services. Most of the methods already discussed in detail in previous chapters have been applied to technologies for adding location capability to cellular systems. They include TOF (in the form of TDOA), AOA, and RSS. Multifrequency techniques have not been used because they are not generally adaptable to the air interfaces up to third generation technologies. The adoption of OFDM for cellular systems in future evolution of technologies may very well add multifrequency techniques to the repertoire of methods that are already being used for the various network types and applications.
The driving reason for adding location capability to cellular communication was physical security for the holders of handsets, at least in the United States where cellular providers are obligated by telecommunication regulations to provide positioning as a nonsubscription service. Once the infrastructure and/or handset models were available for providing location, it was only natural the range of services based on location would start to bloom. In Europe and other world regions it is these commercial services that are generating the inclusion of location capability in cellular networks. Some of the most common location-based services, other than personal security, are the following:
Provision of transport navigation instructions;
Identification of nearby...
