A two‐level cooperative game‐based approach for joint relay selection and distributed resource allocation in MIMO‐OFDM‐based cooperative cognitive radio networks

Abstract

AbstractWe consider the downlink of a multi‐input multi‐output orthogonal frequency‐division multiplexing‐based cooperative cognitive radio network in which the secondary users (SUs) with extra resources work as relay to help the SUs with less available resources to improve their utility in terms of the throughput and fairness by forming a coalition graph. We model the problem of joint relay selection and power allocation in multi‐input multi‐output orthogonal frequency‐division multiplexing‐based cooperative cognitive radio network as a two‐level cooperative game problem, and the objectives of this work are twofold. Firstly, we assign each weak SU to one of the relays (rich SUs) through solving a problem achieved by a non‐transferable utility coalition graph game, and this comprises the first level of the game. Secondly, we jointly allocate available channels to the SUs such that no subchannel is allocated to more than one SU and simultaneously optimise the transmit covariance matrices of nodes based on the Nash bargaining solution, which is the second level of the game. We further model the network as a multi‐cell scenario with small serving areas. After relaxing the problem and convexifying the relaxed version, we develop an optimal distributed algorithm, using dual decomposition. Afterwards, we propose a dynamic distributed resource allocation algorithm for this purpose. Simulations confirm the convergence of our distributed algorithms to the globally optimal solution of the two‐level game. Copyright © 2014 John Wiley & Sons, Ltd.