Time-Reversal Division Multiple Access Over Multi-Path Channels
The multi-path effect makes high speed broadband communications a very challenging task due to the severe Inter-Symbol Interference (ISI). By concentrating energy in both the spatial and temporal domains, Time-Reversal (TR) transmission technique provides a great potential of low-complexity energy-efficient communications. In this paper, a novel concept of Time-Reversal Division Multiple Access (TRDMA) is proposed as a wireless channel access method based on its high-resolution spatial focusing effect. It is proposed to use TR structure in multi-user downlink systems over multi-path channels, where signals of different users are separated solely by TRDMA. Both the single-transmit-antenna scheme and its enhanced version with multiple transmit antennas are developed and evaluated in this paper.