Power Randomization for Iterative Detection Over Random-Access Fading Channels

In this paper, we focus on throughput performance of multiuser communications systems over fading channels. More specifically, we consider the uplink where multiuser detection under asynchronous transmissions is exploited for random-access management and iterative receivers are considered for practical issues. Normalized throughput is evaluated through a semi-analytic procedure in order to avoid time-consuming simulations. Power randomization is explored as a means for improving performance through system asymmetries. It is found beneficial, particularly in case of overloaded systems operating at low-to-medium signal-to-noise ratio, where it allows reducing significantly the number of iterations at the receiver.