Hand-off using fuzzy logic

The cellular industry is moving towards smaller cell sizes in order to increase channel reuse. One cell structure under consideration is the microcell. It has been articulated, however. That before the microcell can be deployed successfully there are two major issues to be resolved. These are: (i) the need for a fast, but stable hand-off algorithm which can clearly differentiate the boundary between adjacent cells and (ii) the need to find a hand-off algorithm which will respond quickly to the Manhattan Street Corner phenomenon-where the signal strength from the basestation to mobile station drop by over 20 dBs in a few meters after the mobile station turns a corner. The authors present two examples illustrating how fuzzy logic may be applied to resolving these hand-off issues. The first fuzzy hand-off algorithm uses the received signal strength and distance measurements to make a hand-off decision. While, the second uses the past signal history to predict a future value, and hence determine the hand-off initiation point