Opportunistic cooperation in wireless ad hoc networks with interference correlation

Abstract

Compared with conventional direct transmissions, the cooperative transmissions are not always beneficial and redistribute the interference over the network coverage area due to relay transmissions. In this paper, we propose an opportunistic cooperation strategy for a wireless ad hoc network with randomly positioned single-hop source-destination pairs and relays, where each source-destination pair activates the cooperative transmission only when the number of potential relays is not smaller than a cooperation threshold. Such a threshold determines the proportion of concurrent cooperative transmissions and it can be adjusted to enhance the overall network performance. The correlation of nodes’ locations induces the correlation of interference power. Based on stochastic geometry, we derive the correlation coefficient of interference power at a destination during the transmission periods of the sources and relays. The outage probability of opportunistic cooperation is derived for selection combining, while taking into account the interference correlation, relay selection strategy, and spatial distributions of sources and relays. Extensive simulations are conducted to validate the performance analysis. The analytical results evaluate the effectiveness of opportunistic cooperation and provide useful insights on protocol design and parameter setting for large-scale networks.