A Differential QAM Scheme for Uplink Massive MIMO Systems

An uplink massive MIMO system with a single antenna transmitter and a single receiver with a large number of antennas is considered. For this system we propose one new differential QAM scheme based on the division operation. Specially, by designing one looking-up table, we provide the transmitted differential QAM symbol generating process and the non-coherent detection method, which is only based on two adjacent received signals, while not using any instantaneous channel state information. At last the bit error rate (BER) performance is simulated and the simulation results have shown that the new proposed differential QAM scheme achieves much better performance than the other differential QAM or differential amplitude phase shift keying (DAPSK) schemes in uplink massive MIMO systems, especially for higher dimensional modulation constellations.