Fixed Channel Assignment in Cellular Mobile Telecommunication Systems - Using packed patterns to reduce the search space

Pedro Castro Borges, and Rene Victor Valqui Vidal


The problem of fixed channel assignment in cellular communication systems with nonuniform traffic distribution is addressed. The criterion for channel allocation is minimising the average blocking probability. Methods for finding a good allocation can be to different extents based on first building a number of sets of cochannel cells or allocation patterns and then assigning them to channels. This usually implies that only a subset of the feasible region is attainable. The approach suggested in this paper uses the concept of packed pattern, since all patterns in an optimal solution will be of that kind. With a constructive method, the entire set of packed patterns is built and used in the optimisation process. The complexity (large-scale and nonlinearity) of the resulting problem suggests the use of general search procedures (local search, tabu search, simulated annealing, etc) which have the further advantage of flexibility when dealing with extensions to the problem. A neighbouring structure is used, that facilitated the calculations while still allowing for the search in the entire solution space. A summary of extensive numerical experiments is presented. The outcome is an improvement over previous results.

Keywords: mobile communication systems, search methods, channel allocation.

IMM Technical Report 25/96

Last modified February 4, 1997

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