Adaptive measurement intervals for handoffs

The author exploits the information in signal strength measurements to improve the quality of the handoff decisions in cellular systems. As a vehicle moves, the signal strength changes due to distance from the base station, slow fading, and fast fading. The fluctuations due to slow and fast fading are usually considered as noise in this decision making process. This leads to a tradeoff problem for the averaging interval for the signal strength measurements. If the interval is too short, the fading fluctuations are not sufficiently smoothed out. If the interval is too long, the handoff mechanism is too sluggish. By considering this tradeoff, a method is presented to adaptively change the averaging interval. The method is based on estimating the maximum Doppler frequency, the key to the tradeoff