On Outage Capacity for Incremental Relaying with Imperfect Feedback

We investigate the effect of imperfect feedback on the ǫ-outage capacity of incremental relaying in the low signal-to-noise ratio (SNR) regime. We show that imperfect feedback leads to a rescaling of the pre-log factor (comparable to the multiplexing gain for networks operating in the high SNR regime) and thus reduces the ǫ-outage capacity considerably. Moreover, we investigate the effect of different degrees of feedback reliability on the system performance. We further derive a simple binary tree-based construction rule to analyze networks with an arbitrary number of relay nodes with respect to imperfect feedback. This rule can directly be mapped to a comprehensive matrix notation. Keywords— cooperative communications, incremental relaying, feedback, ǫ-outage capacity