Uninterrupted Connectivity Time in THz Systems Under User Micromobility and Blockage

Abstract

Terahertz (THz) band is considered as the main candidate for new radio access technology in sixth-generation (6G) cellular systems. However, the performance of these systems will be severely affected by not only blockage but user equipment (UE) micromobility in hands of a user. The negative effects of these phenomena can be alleviated by utilizing the multi-connectivity functionality that allows UE to maintain two or more links to nearby base stations (BS) and use them when the currently active link is lost. By accounting for THz specific propagation, antenna and beamsearching design, the density of THz BS deployment, and multi-connectivity operation, we investigate the successful session completion probability under both types of impairments. Our results indicate that the gains of multi-connectivity are observed up to 5 simultaneously supported links and heavily depend on the application outage tolerance time and is mostly affected by micromobility. To improve it, one needs to ensure that the application may tolerate outage caused by beamsearching time which is on the order of milliseconds.