Joint Subchannel and Power Allocation for Secure Transmission in Femtocell Networks

This paper studies the physical layer security problem in the downlink two-tier femtocell network system, where an eavesdropper wiretaps the legitimate macrocell users. In this system, femtocell base stations (FBSs) can reduce the performance of eavesdropper through cochannel interference, which in turn improves the secure transmission rate of the entire system. The power allocation problem of the FBSs and macro base station (MBS) has an important influence on the cochannel interference and system performance in femtocell networks. In this paper, the power allocation problem is modeled as an optimization problem. We aim to maximize the secrecy rate and reduce energy consumption. Based on this, a joint subchannel and power allocation algorithm is proposed. Simulation results show that the proposed algorithm can effectively improve the network transmission performance and reduce the energy consumption, compared with existing algorithms.