Novel Signal Design for Next Generation Ultra-Reliable Wireless Communications

Time-domain interleaving (TDI) is a novel signal design based on orthogonal frequency division multiplexing (OFDM). TDI can offer three-dimensional frequency-time diversity leading to a superior symbol error rate (SER) performance for various channel conditions with fading and interference. The performance of the proposed signal design is evaluated using zero-forcing (ZF) and minimum mean-square-error (MMSE) equalizers where the signal-to-noise ratio (SNR) and signal-to-interference-plus-noise ratio (SINR) are derived and used to evaluate the SER, outage probability (OP), and diversity order. The results obtained demonstrate that the proposed signal model with MMSE equalizer achieves ∼40 dB gain over OFDM in Rayleigh fading channels, and it is only 2 dB from the Gaussian channel SER in Rician channels. The proposed scheme also outperforms other state-of-the-art techniques such as interleave frequency division multiplexing (IFDM) and orthogonal time frequency space (OTFS). The proposed system architecture generally follows the conventional OFDM system model, which emphasizes its compatibility and low complexity.