Towards a better diversity-multiplexing tradeoff in MIMO systems

Multiple-input multiple-output (MIMO) systems can provide two kinds of gain: diversity gain and multiplexing gain. Most existing MIMO schemes, including space-time coding and layered space-time, aim at maximizing either of them. Group transmission and detection is a good way to get a tradeoff between these two gains. In this paper, the diversity-multiplexing tradeoff functions of 3 schemes based on group transmission and detection, quasi-orthogonal group space-time (QoGST), group layered space-time (GLST) and layered space-time block codes (LSTBC), are provided and a vivid comparison among them demonstrates that QoGST achieves the best diversity-multiplexing tradeoff. GLST also gets significant gains over LSTBC. Simulation results will validate the analysis and show that QoGST can achieve at least 3 dB gain over GLST and 12 dB over LSTBC at a FER of 10^-3, for instance.