Using relays--which consume hardware space--“in wireless networks can potentially lead to significant capacity increases. However, within an asynchronous multi-user communication setting, relaying might cause more interference in the network and significant sum-rate deterioration may be observed” [1]. To protect themselves against interference, many wireless protocols create an exclusion area around receivers, in which no transmission node is allowed. This method, in turn, increases the throughput in wireless networks. “It is crucial to determine the optimal trade-off between the amount of throughput gain obtained via cooperation and the amount of” space required for relays [1].

In this paper, Lichte et al. analyze the trade-off when cooperation is used, and calculate the total interference caused by adjacent nodes. Moreover, they use the result from a previous phase to formulate the throughput equations for three types of transmissions--direct, noncooperative relaying (NCR), and selection decode-and-forward (SDF)--as functions of exclusion areas. Their work shows that capacity gains are highest and exclusion areas are smallest when SDF is used. This suggests that the cooperation technique improves capacity in wireless networks, with additional investment in network hardware that is required to deal with high interference.

This paper is about an interesting topic, and the mathematical tools the authors use can be applied to other wireless networking research areas. I recommend it to any researcher who is interested in the subject.