Performance analysis for 5G beamforming heterogeneous networks

The heterogeneous network (HetNet) is an attractive solution to solve limited spectral efficiency, the increasing traffic demands, and crowded coverage. In 5G, massive multiple-input multiple-output and millimeter-wave technologies are considered to explore high array gain and alleviate high path loss with beamforming. In this paper, we propose a general tractable model for signal-to-interference-plus-noise ratio (SINR) analysis with cell expansion and beamforming for 5G. In this HetNet, each layer is characterized by particular parameters such as base station (BS) density, transmission power, beam gain, beamwidth, propagation loss, and bias factor. In our model, the expressions of outage probability for each layer and the whole network, which represent the SINR distributions, are derived through a typical user. We also analyze the rate performance by the minimum average user rates and the rate coverage probabilities. Furthermore, the spectrum reuse strategy, some layers are spectrum separation while others are spectrum sharing, are considered to consistent with the existing and future cellular network. From the simulations, system performance can be greatly improved by beamforming and affected by beamwidth, and the optimal bias changes with BS density and path loss. Furthermore, the proposed method provides practical deployment guidelines with some determined parameters.