Resource Allocation for OFDMA-Based Cognitive Networks: An Interference-Efficient Perspective

In this paper, the interference-efficient based resource allocation for uplink transmission in an OFDMA-based cognitive radio network is studied. The interference efficiency (IE) is defined as the total data rate of secondary users (SUs) over sum interference power imposed on primary users (PUs). The objective is to maximize the total IE of SUs subject to transmit power constraints of SUs, subcarrier assignment constraint and the interference power threshold constraints of SUs. The original mixed integer fractional programming problem is converted into the convex one which is solved by using the convex optimization technique. Simulation results show the effectiveness of the proposed algorithm in terms of the interference to PUs and transmission efficiency.

I. Introduction

In recent years, with the increase of intelligent terminals and wireless devices, the limited spectrum resource is getting more and more nervous. Therefore, cognitive radio (CR) [1] as a promising technique is proposed to allow the unlicensed users (also called secondary users, SUs) to utilize the frequency bands of licensed users (also called primary users, PUs). As a result, the whole idle spectrum of the wireless network can be fully and effectively reused. For underlay cognitive radio networks (CRNs) [2], [3], the quality of service of PUs can be guaranteed by an interference temperature threshold which imposes the interference power from all SU transmitters (SU-Txs) to each PU receiver (PU-Rx) under an interference level.