Sr Serghey Tiourine

Local search algorithms for the radio link frequency assignment problem

Radio link frequency assignment problems arise in practice when a network of radio links has to be established. Each radio link has to be assigned an operating frequency. The frequency assignments have to comply with certain regulations and physical characteristics of the transmitters. The interference level between frequencies assigned to different links has to be small, since otherwise communication will be distorted. Two objectives are considered: the total interference costs and, in case of no interference, the frequency spectrum usage. We develop several approximation algorithms for the problem and compare their performance on some practical instances. We also develop a lower bounding technique based on a nonlinear relaxation in order to estimate the quality of the approximate solutions for some of these instances.

Algorithms for Radio Link Frequency Assignment: The Calma Project

The radio link frequency assignment problem occurs when a network of radio links has to be established. Each link must be assigned an operating frequency from a given domain. The assignment has to satisfy certain restrictions so as to limit the interference between links. The number of frequencies used is to be minimized.Problems of this type were investigated within the CALMA project by a consortium consisting of research groups from Delft, Eindhoven, London, Maastricht, Norwich, and Toulouse. The participants developed optimization algorithms based on branch-and-cut and constraint satisfaction, and approximation techniques including a variety of local search methods, genetic algorithms, neural networks, and potential reduction. These algorithms were tested and compared on a set of real-life instances.