A unified approach to the assignment of radio channels on a regular hexagonal grid

In radio systems, quality of service is achieved by assigning channels with reference to a set of protection ratios, which in a simplified setting may be replaced with frequency-distance bounds. This paper considers the assignment problem on a lattice of hexagonal cells, with the allowed assignments generated by regular tilings of a single polyhex. The main aim is to investigate the interplay between the cochannel and adjacent channel separations without restricting the assignments unnecessarily. The outcome is a unified framework in which all previous results appear as particular cases. The possible cochannel lattices are carefully classified, and then an algorithm is developed, which assigns channels on any cochannel lattice so that the adjacent channel separation is maximized. In this way, a library of the best assignments can be compiled. The results are of relevance to a range of applications, including both broadcast and mobile systems.