Autonomous adaptive frequency assignment for TDMA portable radio systems

A simple autonomous procedure performed by each radio port (base station) to determine its own transmitting frequency is proposed. This procedure consists of signal strength measurements and an algorithm which selects the frequency with minimum interference from other ports. The algorithm converges rapidly while adapting to changes of operational conditions, such as installing new ports, which changes the system configuration, or adding new buildings, which causes different shadow fading. This method is significantly superior to a random assignment method both in resultant channel quality and in traffic-handling capability. For a regular-grid configuration, this method performs nearly as well as an a priori optimal frequency assignment method. It is also found that this assignment algorithm is robust against short-term signal fluctuations and it can be performed completely autonomously by each radio port