Extending mmWave Deployment in the Next-Generation Network: Coverage and Reliability Enhancements

Millimeter wave (mmWave) communication has been proposed as an enabling technology for the evolution from 4G to 5G. Using the enormous bandwidth between 24.25 GHz-71.0 GHz, this technology allows for a huge improvement in channel capacity compared to sub-6 GHz bands [1]. In addition, the smaller size of individual antenna elements also supports the integration of larger antenna arrays for beamforming and spatial multiplexing. 3GPP has therefore supported this technology and defined corresponding technical specifications for frequency range 2 (FR2) bands in 5G NR. Although mmWave communication has shown significant potential in research, its commercial deployment has not thrived as expected. Major deployment only happens in US and Japan, while in other regions (China, Europe, South Korea, etc.) the deployment is generally limited. Besides, the coverage can be almost non-existent in many urban areas even in those countries that deploy mmWave cells. The difficulty commercializing 5G mmWave results from inherent challenges which need solutions to fully unleash its benefits. In the following sections, we discuss five major challenges and elaborate on three enabling technologies for coverage and reliability enhancement that can be the current focus. Other technologies, such as reconfigurable intelligent surface, will be considered in future research.