Energy efficient joint chunk and power allocation for chunk-based multi-carrier cognitive radio networks

This paper investigates the problem of energy efficient resource allocation in a chunk-based multi-carrier cognitive radio (CR) network. Chunk-based resource allocation is adopted where subcarriers are grouped into chunks to be allocated to the secondary users (SUs). The objective is to maximize the energy efficiency of the CR network while also satisfying the transmit power constraint as well as the interference power constraint for protecting the primary user (PU). For this, based on Dinkelbach method and dual optimization method, an efficient iterative algorithm is proposed. The impacts of the interference power constraint, the transmit power constraint, number of subcarriers within the chunk and the channel coherence bandwidth on the performance of the proposed algorithm are examined by simulations. It is shown that the proposed algorithm not only converges fast but also achieves almost the same performance as the exhaustive search algorithm does. It is also shown that the performance of the proposed algorithm significantly improves compared to the max-sum-rate algorithm and the equal power allocation algorithm especially for large transmit power and interference power limits. In addition, it is shown that the proposed algorithm achieves higher energy efficiency with less number of subcarriers within the chunk.