Predicting 5G: Performance Analysis of Millimeter Wave Cellular Networks

With advances in RF circuits, the era of operating cellular networks in millimeter wave (mmWave) bands is coming. The lightly licensed mmWave band offers the potential to solve the spectrum gridlock in current cellular networks. It is not clear, however, whether both high data rates and coverage in signal-to-noise-and-interference ratio (SINR) can be achieved in mmWave cellular networks; as the propagation conditions and hardware constraints become different, and prior microwave network models do not directly apply to mmWave systems.

Leveraging concepts from stochastic geometry and random shape theory, WNCG graduate student Tianyang Bai and WNCG Professor Robert Heath have proposed an analytical network model that incorporates key features of mmWave cellular systems, such as blockage effects and directional beamforming.  In their recent paper, the model was applied to analyze the coverage and rate performance in mmWave cellular networks. In their study, they derived expressions for SINR and rate distributions as functions of the base station density, parameters of blockages (e.g. buildings in urban areas), and geometries of beamforming. Based on their analyses, it has been found that mmWave networks will move from a power-limited regime to interference-limited regime when increasing base station density. More importantly, they showed that mmWave cellular networks can achieve comparable SINR coverage and significantly higher achievable rates than conventional microwave networks when the base station density is sufficiently high. Their results indicate that in dense mmWave networks, the SINR and rate performance is mostly determined by the ratio of base station density to the blockage density.

This research funded by the National Science Foundation under Grant No. 1218338 and 1319556 and a gift from Huawei.

Paper: T. Bai and R. W. Heath, Jr., "Analysis of coverage and rate in millimeter wave cellular networks", Submitted to IEEE Trans. Wireless Commun., March 2014 Available on http://arxiv.org/abs/1402.6430.