Optimization of MultiBasestation Codebook Beamforming for mmWave Connections to High Speed Trains The exploration of mmWave technology for future public broadband communications is set to mitigate congestion in the lower spectra bands and is poised to provide multiGigabit radio access to urban users, as well as road and rail passengers. However, due to the unique and challenging propagation characteristics experienced in the mmWave bands, and particularity those in rail environments, a large number of trackside Base Stations (BSs) may be required to provide continuous coverage. This paper uses advanced simulation techniques to quantify the minimum number of required trackside BSs, and hence to minimise the capital and operational costs of the network. Our simulation results are supported by realworld tracktotrain measurements captured on the UK test track. By combining detailed 3D geographic databases with mmWave propagation models and accurate simulations of the beamforming antenna arrays and mmWave data modems we present an analysis of the theoretic coverage along a 1.9km section of UK rail track. Simulated data rates are presented for each of the 36 potential trackside sites. All studies are performed using a carrier frequency of 60 GHz. The beamforming codebooks used in this work were taken from the mmWave modems used in the rail trials. The codebook choices at the trackside and ontrain modems were optimally selected to minimise the number of required BS. Statistical analysis is provided for two different Effective Isotropic Radiated Powers (EIRP). For the higher EIRP level (60dBm), results show that an interBS spacing of just under 1000m is viable. This allows Gigabit data rates to be delivered along the entire 1.9km test track using just two trackside mmWave BSs.

Performance Evaluation of Linear Precoding mmWave MultiUser MIMO Systems with NYUSIM Channel Simulator In this paper, we evaluate the performance of the digital beamsteering (DBS) precoder in multiuser multipleinput multipleoutput (MIMO) systems operating at mmWave frequencies. This evaluation is done using a 3D mmWave statistical channel model developed based on outdoor extensive measurement in New York city. The NYUSIM channel simulator generates 3D realistic statistical temporal and spatial parameters. The DBS performance is evaluated in terms of capacity achieved as a function of the number of users and compared with two classical precoders, namely, zero forcing (ZF) and conjugate beamforming (CB). The base station is equipped with three different antenna array configurations: uniform linear array, uniform square array and uniform rectangular array.Simulation results show that DBS can be realistically considered as an attractive precoder for mmWave multiuser MIMO system with tens of antennas at the base station; tradingoff performance, low implementation complexity and less overhead.