A Dynamic Group-Connected Design With True-Time-Delay for Wideband THz Beamforming

Wideband Terahertz (THz) beamforming is a promising technology in the sixth generation (6G) wireless communications. The combination of ultra-wide bandwidth and ultra-massive multiple-input multiple-output (UM-MIMO) results in severe beam squint issues, leading to sharp decrease in the spectral efficiency. Replacing the phase shifters by a large amount of true-time-delays (TTDs) could eliminate the beam squint effect, but leads to unbearable power consumption. It becomes an enormous challenge to mitigate the beam squint effect while maintaining high energy efficiency simultaneously. This paper proposes a novel dynamic group-connected hybrid beamforming architecture with TTD (DGC-TTD) to tackle the above issue. Furthermore, a switch-aided delay-phase beamforming (SDPB) algorithm is proposed for the DGC-TTD architecture, which consists of a delay-phase design (DPD) procedure and a random switch selection (RSS) procedure to achieve the optimal tradeoffs between the spectral efficiency and the power consumption. The simulation results demonstrate that the DGC-TTD architecture with the proposed algorithm provides the near-optimal spectral efficiency and the maximal energy efficiency comparing with existing benchmark results.