LLR-based Ordering in Amplify-and-Forward Cooperative Spatial Multiplexing System

The paper investigates and evaluates the application of log-likelihood ratio-based ordering in the decoding stage of amplify-and-forward cooperative spatial multiplexing system. The cooperative spatial multiplexing detects signals transmitted from the source with successive interference cancelation algorithm whose performance varies, depending on the ordering schemes applied. Log-likelihood ratio-based ordering uses and exploits the a posteriori information of the received signal at the destination to get a more accurate final estimation at the decoder output. Based on the evaluation, the authors demonstrate that with marginally extra complexity, log-likelihood ratio based-ordering offers better performance compared to signal-to-noise ratio-based ordering.