Fuzzy handoff algorithms for wireless communication

In order to manage the high call density expected of future cellular systems, microcells must be used. A migration to microcells will increase the number of handoffs, and require faster handoff algorithms - in terms of decision making. In the case of line-of-sight transmission, it is important that the handoff algorithm detects the cell boundary early enough, otherwise this will lead to channel dragging into the new cell subsequently increasing the chance of co-channel interference. In the case of non-line-of-sight transmission, a mobile station on turning a street corner will experience a phenomenon known as the Manhattan corner effect that causes the received signal 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 presents 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 simulation show that fuzzy is a viable option for microcellular handoff. (C) 2000 Elsevier Science B.V. All rights reserved.