Cooperative Space-Time Coded Transmissions in Nakagami-m Fading Channels

In this paper we evaluate outage performance of a cooperative transmission protocol over fading channels that requires a number of relaying nodes to employ a distributed space-time coding scheme. Diversity provided by this technique has been widely analyzed for the Rayleigh fading case. However, ad-hoc and sensors networks often experience propagation environments where the line-of-sight component is either non zero or, in some cases, dominates compared to the random non line-of- sight components. By considering the Nakagami-m as a generic framework for describing the statistic of the fading impairments, this paper evaluates a set of fading inequalities that define settings where the benefits of collaborative transmission from multiple relays when varying fading parameters. These cooperative fading regions define the propagation settings that make cooperation preferable to multi-antenna non-cooperative transmission.