Realizing Massive MIMO Effect Using a Single Antenna: A Time-Reversal Approach
Massive MIMO has shown the great potential in improving the achievable rate with a very large number of antennas. However, several critical challenges in designing the analog front-end and coordinating the large-scale antenna array have to be carefully addressed. Does there exist an alternative that can achieve similar system performance to massive MIMO with a simpler design? In this paper, we show that by using time-reversal approach, with a sufficiently large bandwidth, one can harvest massive multipaths naturally existing in the rich-scattering environment to form a large number of virtual antennas to achieve the desired massive MIMO effect with a single antenna. We analyze the expected achievable rate of the time- reversal system with MMSE waveform. Furthermore, the corresponding asymptotic achievable rate under a massive multipath setting is derived. Experiment result based on real channel measurements shows that, even with only a single antenna, the time- reversal wideband system can achieve comparable performance as the massive MIMO system in terms of expected achievable rate.