Cluster-Based Multi-Hop mmWave Networks: Relay Selection and Performance Analysis

One of the most promising technologies for 6G is the use of millimeter waves (mmWaves) because these waves provide wide bandwidth and high data rates. However, these waves are highly sensitive to blockage and hence have short range. Thanks to the relay-aided multi-hop transmission, we can overcome this limitation and improve the range of mmWaves. In this paper, we investigate different types of relay selection schemes and routing for the cluster-based multi-hop (CBMH) mmWave network. These schemes are classified into bypass-based and without bypass, where bypass refers to the direct links from the intermediate clusters to the destination. We analyze and simulate these schemes in terms of the blockage probability, the end-to-end (e2e) normalized energy consumption (NEC), the e2e average hop count (AHC) and the spectral efficiency. The analytical results and the simulations show that the bypass-based relay selection schemes outperform their counterparts without bypass in terms of the blockage probability, the e2e AHC and the spectral efficiency. However, in terms of the e2e NEC, the situation is reversed. The simulation results also show that the proposed relay selection schemes perform very close to the benchmark in terms of the spectral efficiency.