Channel assignment in cellular networks without channel separation constraints

This paper deals with the channel assignment problem in cellular systems. Usually this problem uses models that involve defining and solving a set of channel separation constraints between pairs of base station transmitters i.e. a graph colouring formulation. These constraints are derived by considering the potential interference at reception points within the service area of one base station from an interfering signal radiating from another base station i.e. considering interference from a single source. We show that significantly improved solutions can be obtained by directly considering the carrier-to-interference ratio at the reception points that takes into account interference from multiple sources. No channel separation constraints need be used. Results are presented for a local search algorithm on three practical cellular networks.