Capacity maximization in cooperative CRNs: Joint relay assignment and channel allocation

Cooperative communication (CC) can offer high channel capacity and reliability in an efficient and low-cost way by forming a virtual antenna array among single-antenna nodes that cooperatively share their antennas. It has been well recognized that the selection of relay nodes plays a critical role in the performance of multiple source-destination pairs. Unfortunately, all prior work has made an unrealistic assumption that each source-destination pair communicates over a dedicated channel with no mutual interference. In this paper, we study the problem of capacity maximization using cooperative communication in a cognitive radio network by jointly considering the relay assignment and channel allocation under a finite set of available channels, where the interference must be considered. It is proved to be NP-hard and a heuristic algorithm is proposed. Moreover, we exploit the network coding opportunities existing in CC that can further increase the capacity. Extensive simulations are conducted to show that the proposed algorithms can achieve high total capacity under various network settings.