Implementation of a Multi-User Detector for satellite return links on a GPU platform

Due to the scarcity and high cost of satellite frequency spectrum, it is very important to utilize the available spectrum as efficiently as possible. The efficient usage of the spectrum in the satellite return link is a challenging task, especially if multiple users are present. In previous works Multi-User Detection (MUD) techniques have been widely studied to increase the spectral efficiency of the satellite return link. However, due to the high computational complexity and its sensitivity to synchronization and channel estimation errors, only few implementations of MUD for satellite communications exist. In this paper a novel Graphics Processing Unit (GPU)-based Software Defined Radio (SDR) implementation of a MUD receiver for transparent satellite return link is presented, which uses iterative channel estimation and decoding. The implementation can cope with the presence of strong phase noise. In addition to its high flexibility and low cost, with the GPU acceleration our SDR MUD receiver implementation achieves a decoding throughput of 270 Kbps using a single GPU card.