Performance Analysis of One-Source-with-One-Helper Transmission over Shadowed κ-µ Fading Multiple Access Channels

We investigate the performance of correlated sources transmission over multiple access shadowed κ-µ fading channels, in which one of the correlated sources needs to be recovered at the destination, whereas the other serves as a helper. We determine the sufficient condition for lossless coding by the intersection of the modified Slepian-Wolf region and the multiple access channel region. The outage probability upper bounds are derived based on the sufficient condition, with the Gaussian codebook capacity and the constellation constrained capacity, respectively. The difference between the outage probabilities derived with the two kinds of capacities is found to be very minor, when the spectrum efficiency or source rate is low; however, with high spectrum efficiency or high source rate, such difference becomes significant. A closed-form outage approximation is also obtained at the high signal-to-noise ratio region. The accuracy of the analytical results is verified by the Monte-Carlo simulations. We find that shadowing significantly affects the outage performance, however, it has no effect on the diversity gain. Furthermore, we study the power allocation between the source and the helper to minimize the outage probability and find that generally more power should be allocated to the helper in the case with higher source-helper correlation.