Equipment selection heuristics for microwave fixed links

Microwave fixed links use highly standardized radio equipment and, in the radio equipment standard referenced in this paper, there is a choice between exactly two radio systems when the assigner wishes to resolve a specific data rate exactly: one using a relatively lower‐order modulation scheme and one a relatively higher‐order scheme. Although the higher‐order equipment requires less bandwidth for an isolated link, these systems radiate at higher powers and require larger protection ratios in the radio interference environment which lead to well‐established trade‐offs between modulation, bandwidth, equivalent isotropic radiated power, and frequency assignment criteria. Our earlier research showed that by extending the Frequency Assignment Problem to include equipment selection and using lower‐order modulation equipment on selected links, we can actually reduce the overall span of frequencies required for a network frequency assignment. This work focused on the development of integer programming formulations and analyzed the exact solutions obtained. Exact solutions are impractical for real world problems; hence, here we focus on the development of heuristics for equipment selection. We can model the fixed link network as a complete graph where the vertices represent fixed link frequency assignment requests and the edges represent interference between pairs of vertices. Using a graph theoretic analysis of the interference problem, we propose heuristic techniques and discuss the relative success of our approach in this article.