Optimal Channel Assignment Schemes in Underlay CRNs with Multi-PU and Multi-SU Transmission Pairs

Abstract

In underlay spectrum sharing scheme, both channel assignment and power allocation will affect network performance such as throughput, etc. This paper first defines the joint channel and power control problem, which aims to optimize the max-total and max-min throughput of SUs, with interference constraints on primary receivers. For the max-total problem, we formulate the problem as a bipartite matching and derive a maximum weighted matching based algorithm STMA to solve this problem. For the max-min problem, on the basis of the ORA algorithm, we derive a polynomial time algorithm OCAA to iteratively assign the channels to each SU pair under the power constraint. Simulation demonstrates, the throughput of SU network grows with the maximum transmission power of SUs below the interference power of PUs. STMA algorithm achieves an average of 46.67 % performance gain when path loss component $\alpha =2$ and 13.08 % enhancement when $\alpha =3$ compared with random algorithm. The OCAA algorithm effectively ensures the max-min fairness of the capacity among SU pairs in finite iterations and achieves at least 97 % performance gain than the random method under most cases.