A Cognitive Radio Relay Selection Scheme with Fairness Analyses in Two-Tier Femtocell Networks

The effective cross-tier interference (CTI) mitigation is a key technique for the macrocell and femtocell two-tier heterogeneous networks. In this paper, a cognitive radio relay selection (CRRS) scheme is proposed to improve the received power of the macrocell users served by the macrocell base station (MBS). The scheme is intended to ensure the macrocell users can endure much more interference from the femtocell users in order to improve the quality of service (QoS) of the femto-networks. In addition, the fairness of the femto-networks is analyzed, with the objective of accounting for the maximal density of femtocell base stations that located in a certain area. Simulation results demonstrate that, compared with the existing works, the proposed scheme can not only increase the number of the femtocell users whose Signal-to-Interference-plus-Noise-Ratio (SINR) requirements are guaranteed, but also improve the average SINR of the femtocell users.