Improving throughput by fine-grained channel allocation in cooperative wireless networks

Cooperative communication provides an efficient and low-cost way to achieve spatial diversity without deploying multiple antennas on each node in wireless networks. In a channel-constrained environment, such as cognitive radio networks, the channel allocation as well as relay assignment have been identified as two critical factors in determining the performance of multiple source-destination pairs. However, the advantage of channel diversity has little been exploited in such networks under a simplified model where the transmissions within a cooperative communication pair are on a common channel. In this paper, we consider a fine-grained channel allocation scheme that the source and the relay can work on different channels to complete a signal transmission. We study its performance gain in maximizing the minimum throughput among multiple source-destination pairs in channel-constrained wireless networks with a number of dedicated relay nodes. This problem is proved to be NP-hard and an online algorithm is proposed for a dynamic wireless network where the accessible channels of each node may vary from time to time. Extensive simulations are conducted to show that the proposed fine-grained channel allocation scheme can effectively improve the performance under various network settings.