Fuzzy handoff algorithms for wireless communication

In order to manage the high call density expected of future cellular system s, microcells must be used. A migration to microcells will increase the num ber of handoffs, and require faster handoff algorithms - in terms of decisi on making. In the case of line-of-sight transmission, it is important that the handoff algorithm detects the cell boundary early enough, otherwise thi s will lead to channel dragging into the new cell subsequently increasing t he chance of co-channel interference. In the case of non-line-of-sight tran smission, a mobile station on turning a street corner will experience a phe nomenon known as the Manhattan corner effect that causes the received signa l level to drop by 20-30 dB in 20-30 m. This corner effect problem can lead to a loss of communication if not identified early enough. This paper pres ents two new handoff techniques using fuzzy logic as possible solutions to microcellular handoff. The first algorithm uses an adaptive fuzzy predictor , while the second uses a fuzzy averaging technique. The results of the sim ulation show that fuzzy is a viable option for microcellular handoff. (C) 2 000 Elsevier Science B.V. All rights reserved.