Channel Allocation in Cognitive Radios

In this project we investigate the problem of channel allocation to a set of users in a centralized Cognitive Radio System. We consider three possible formulations of the problem and explain the relationship of these constraints to physical limiting factors. In the first formulation, we aim to minimize total power used in the system while fulfilling user rate requirements. This problem can be solved as a minimum weight matching problem in a bipartite graph. In the second formulation, we further enforce power constraints per channel. In the last formulation we consider the problem of minimizing impact on each user if the primary user returns. With a few modifications we can map this problem to a Maximum Flow Minimum cost problem, which can be solved by a variation of the Ford-Fulkerson algorithm by augmenting along the minimum cost path.