Power, Subcarrier Allocation and Relay Selection with Interference Managements for OFDM-Based Cognitive Heterogeneous Networks

Abstract

Heterogeneous systems merging a different wireless networks to provide a maximum system capacity and to improve spectrum efficiency. In the Heterogeneous systems the problem of Resources Allocation (RA) and interference management considered as important challenges to maximize a total system capacity. An Orthogonal Frequency Division Multiplexing (OFDM) cognitive radio network is proposed in this paper to a group of small cells assisted by amplify and forward AF two-way relays, with perfect sensing. The RA and relay selection proposed in this paper as a formulation problem, to maximize the total transmission rate for small cell networks within one macro cell. The genetic algorithm GA used as optimization technique to solve this optimization problem. The results showed the ability of this algorithm to effectively determine the frequency and power values that distributed over 256 levels. To solve the problem of cross-tier interference from macro cell base station to small cell users, a theoretical analysis has been performed to calculate it and which included in calculation the total capacity according to Shannon's theory. All equations have been derived and theoretically calculated in this paper, in addition to getting higher transmission rate.