A tractable model for rate in noise limited mmWave cellular networks

The use of millimeter wave (mmWave) spectrum for future cellular systems can be made possible with the use of directional antenna arrays and dense base station deployments. MmWave broadband networks exhibit fundamentally different behaviors compared to conventional sub-3 GHz cellular systems. Prominently, interference and path loss models and the corresponding effect on rate need to be re-examined. We propose a general and tractable model to capture and analyze the key distinguishing features of mmWave cellular networks, and characterize the user rate distribution in such networks. The proposed model and analysis are validated by simulations using real building locations in a region of New York in conjunction with empirically measured mmWave path loss models. Using both the proposed model and simulations, it is shown that unlike interference-limited nature of 4G cellular networks, mmWave cellular networks often tend to be noise-limited, and coverage heavily relies on a user being able to received sufficient power from the serving BS. Further, the cell edge rates are shown to be limited mostly by the base station density and are not necessarily improved by increasing the bandwidth of the system.