Trellis Decoding for Multi-User Faster-Than-Nyquist Transmission

A K-user downlink transmission is considered, wherein the Nyquist sequences of different users are transmitted with different time offsets so that the entire transmitted signal is deemed a K times faster than Nyquist (FTN) signal. An inter-user interference removal technique is proposed that successively removes the interference using successive trellis update. It is shown by simulations that when the power difference between users is large enough, using only one round of trellis decoding, the system approaches the performance of the successive trellis update.