Robustness of cooperative communication schemes to channel models

Cooperative communication to extract multi-user diversity and network coding are two ideas for improving wireless protocols. These ideas can be exploited to design protocols for low-latency high-reliability communication for control. Given the high-performance constraints for this communication, it is critical, to understand how sensitive such protocols are to modeling assumptions. We examine the impact of channel reciprocity, quasi-static fading, and the spatial independence of channel fades in this paper. This paper uses simple models to explore the performance sensitivity to assumptions. It turns out that wireless network-coding is moderately sensitive to channel reciprocity and non-reciprocity costs about 2dB SNR. The loss of the quasi-static fading assumption has a similar cost for the network coding based protocol but has a negligible effect on the protocol that doesn't use network coding. The real sensitivity of cooperative communication protocols is to the spatial independence assumptions. Capping the amount of independence to a small number degrades performance but perhaps more surprisingly, a simple Gilbert-Elliott-inspired model shows that having a random amount of independence can also severely impact performance.