Angle-Domain Partition Beam Pattern Based Low-Overhead THz Wideband Beam Training

To support ultra-high-speed multicast and broadcast services in 6 G system, terahertz (THz) communication is considered to be promising since it can provide tens of gigahertz bandwidth. Generating beams by a large-scale array is essential for THz systems to overcome the severe propagation loss. To realize accurate beamforming, it is vital to obtain angle-domain channel information through beam training. However, the existing beam training schemes suffer from large overhead in timedomain or frequency domain. To solve this problem, an angledomain partition beam pattern (APBP) based beam training scheme is proposed in this paper by considering the delayphase beamforming architecture. The APBP is firstly defined through partitioning the whole angle-domain and generating beams covering each angle-domain partition by each subarray. Then, we propose to utilize two APBPs with coprime numbers of partition to coarsely estimate the channel path angle. After that, a fine-tuning stage is carried out to fine-tune the beam training result surrounding the coarse estimation result. By utilizing APBPs, the proposed scheme can achieve accurate beam training in three time slots, and the frequency-domain overhead is also reduced due to the use of subarrays. Simulation results verify the effectiveness of the proposed scheme.