Mobility-Aware Analysis of Millimeter Wave Communication Systems With Blockages

Millimeter wave (mmWave) communication enables high rate transmission, but its network performance may be degraded significantly due to blockages between the transmitter and receiver. There have been two approaches to overcome the blockage effect and enhance link reliability: multi-connectivity and Ultra-Dense Network (UDN). Particularly, multi-connectivity under a UDN environment facilitates user-centric communication. It requires dynamic configuration of serving base station groups so that each user experiences high quality services. This paper models user mobility and mobility-aware performance in user-centric mmWave communication systems with multi-connectivity, and proposes a new analytical framework based on the stochastic geometry. To this end, we first derive compact mathematical expressions for state transitions and probabilities of various events that each user experiences. Then we investigate mobility-aware performance in terms of network overhead and downlink throughput. This helps us to understand network operation in depth, and impacts of network density and multi-connection capability on the probability of handover related events. Numerical results verify the accuracy of our analysis and illustrate the correlation between mobility-aware performance and user speed. Our findings provide useful insights into the design of user-centric mmWave communication systems.

I. Introduction

Millimeter wave (mmWave) communication is a promising technology for the next generation communication system due to its potential for multi-gigabit throughput. But it has limitations because high frequency signals propagate in a short transmission range only and are vulnerable to blockages due to the physical propagation characteristics of mmWave [1]. Blockages such as buildings, forests, and people incur Non-Line-Of-Sight (NLOS) connections between the mmWave Base Station (BS) and user. This seriously aggravates the Quality-of-Experience (QoE) of users with reduced received signal strength. Therefore it is crucial to manage Line-Of-Sight (LOS) connections well, considering the blockage effect in mmWave communications.