Wideband hybrid precoding techniques for THz massive MIMO in 6G indoor network deployment

Terahertz (THz) communication is becoming an up-and-coming technology for the future 6G networks as it offers an ultra-wide bandwidth. Appropriate channel models and precoding techniques are indispensable to support the desired coverage and to resolve the severe path loss in THz signals. Initially, in this work, the Sub-THz channel (140 GHz) response is investigated by using NYUSIM Channel Simulator for 6G indoor office scenario.The major highlight will be on radio propagation mechanisms, which impact the network performnace in the form of path-loss, received power, time delays, azimuth AoD, Azimuth AoA, Elevation AoD, Elevation AoA and RMS delay in LOS environments. Recent hybrid precoding techniques depending upon frequency-independent phase-shifters not able to cope up with the beam split effect in THz massive MIMO systems, where the directional beams will split into various physical directions at various sub-carrier frequencies. The beam split effect will result in a serious array gain loss across the entire bandwidth, which has not been well investigated in THz massive MIMO systems. Therefore, to address this challenge, delay-phase precoding is proposed in this work. We then extensively investigate its diverse number of time delayers, varying number of antenna elements, and comparison with frequency-mmWave and Sub-THz have been discussed. Finally, the proposed delay-phase precoding techniques outperforms the other existing narrowband and wideband precoding techniques. Therefore,it is an effective technique to implement the future 6G indoor communication network deployment.