The Role of Analog Beamwidth in Spectral Efficiency of Millimeter Wave Ad Hoc Networks

This work considers a millimeter wave (mmWave) ad hoc network, where the analog beam-codebook based beam training is employed to determine the analog beamforming direction for each node. In the analog beam training, a narrow analog beam pattern achieves a high main lobe gain and also reduces the probability of receiving the interference from its main lobe, but it requires high beam training overhead which might in return degrade the spectral efficiency of the network. Thus, there exists a trade-off between the analog beamwidth and the spectral efficiency performance. This motivates us to characterize the spectral efficiency as a function of the analog beamwidth and analyze the role of the beamwidth in the spectral efficiency. Numerical results confirm the effectiveness of the analysis and also provide a suggestion on how to choose the best beamwidth for a given setup.