Although relaying can be very beneﬁcial for wireless systems, understanding which relaying schemes can achieve speciﬁc performance objectives under realistic fading is crucial. In this paper we present a general framework for modeling and evaluating the performance of dual-hop decode-and-forward (DF) relaying schemes over independent and not necessarily identically distributed (INID) Nakagami-m fading channels. We obtain closed-form expressions for the statistics of the instantaneous output signal-to-noise ratio of repetitive transmission with selection diversity. Furthermore, we present a uniﬁed statistical overview of other three signiﬁcant relaying schemes with DF, one based on repetitive transmission with maximal-ratio diversity and the other two based on relay selection (RS). To compare the considered schemes, we present closed-form and analytical expressions for the outage probability and the average symbol error probability under various modulation methods, respectively. Importantly, it is shown that when the channel state information for RS is perfect, RS-based schemes always outperform repetitive ones. Furthermore, when the direct link between the source and the destination nodes is suﬃciently strong, relaying may not result in any gains, and it should be switched oﬀ.
|Journal||Journal of Computer Networks and Communications|
|Publication status||Published - 2011|
|Publication type||A1 Journal article-refereed|