Performance analysis of downlink mmWave networks under LoS/NLoS propagation with blockage and directional beamforming

摘要

Due to the spectrum scarcity in conventional celluar frequency bands, millimeter wave (mmWave) frequency bands are attracting increasing attention as a promising candidate for future wireless cellular communication networks. The performance analysis in terms of coverage and rate of mmWave network is a crucial aspect and has been received an increasing interest in recent literature. However, the impact of LoS/NLoS propagation and outage on the coverage probability and rate of the mmWave network is yet to be completely understood. In this paper, we analyze the performance of mmWave networks considering (a) only Non Line-of-Sight (NLoS) environment and (b) both NLoS and LoS propagation. In particular, we compare the coverage and rate performances of mmWave networks with a more practical blockage model that encompasses an outage state, standard path loss function,and directional beamforming which is implemented using number of antennas and scanning angle at the transmitter and receiver. Further, for more practical and precise analysis, we assume that channel amplitudes are Nakgami-m distributed with different fading parameters for NLoS and LoS communication links. Also, different from existing works, the user association with a BS is assumed with a LoS/NLoS path with the smallest pathloss. Our numerical results depict that the presence of an outage state in blockage model decreases the performance of mmWave network. Also, we show the presence of LoS propagation increases the performance of network at the small average cell radius. Further, the impact of variable number of transmit antennas, scanning angle, and antenna radiation efficiency on the network performance is also addressed.