Location determining technologies are becoming increasingly important in wireless communication systems. The utility of a 911 emergency call placed through a cellular telephone, for example, can be greatly enhanced when the cellular telephone system is able to provide an accurate location of the subscriber making the call.
Many different technologies have been devised for determining location. The resolution of the location determining technologies varies widely depending upon factors such as the type of technology, the amount of data reserved for the location determination, the bandwidth of the location signal, the number of measurements made, the conditions during the measurement, and other factors. Tradeoffs can be made to modify the resolution of the location estimate. In general, for a given location technology, a high resolution estimate can come at the expense of a longer time to fix, a lower battery life, a greater over-the-air overhead, additional signal bandwidth, additional signal strength, and higher latency, in varying combinations.
Many operations which utilize location information do not require high resolution location estimates (or do not require high resolution immediately). For example, location based weather services only require a resolution the size of an entire city. Other operations such as real-time turn-by-turn travel directions can require a very high resolution. There are also operations where a low resolution is sufficient for a quick monitoring of the location and where a high resolution can follow later with longer latency.
Thus, what is needed is method and apparatus in a wireless communication system for adaptively selecting a resolution for determining and reporting location information associated with a portable subscriber unit. Preferably, the method and apparatus will select and report the location information at a resolution preferred for a particular operation that is being performed.