User-Side Proactive Blockage Prediction and Fast Beam Switching in 5G NR Systems

Beam management under blockage has been challenging for millimeter wave communication relying on directional links. The baseline beam management protocols in 5G new radio (NR) are not able to predict and avoid the beam blockage timely, leading to significant link quality degradation and beam switching delays. In this paper, we propose a new dual- beam-sweeping-procedure (DBSP) scheme as well as a proactive blockage prediction and fast beam switching strategy at the user side. Specifically, we propose to only exploit existing resources in 5G NR standards and allocate them for DBSP, i.e., the regular beam sweeping procedure in 5G NR as well as an additional serving beam pair link (BPL) monitoring procedure. The DBSP then facilitates the user-side proactive blockage prediction. Once the beam blockage instance is predicted, users could determine candidate BPL earlier for fast beam switching so that the delays of beam switching can be reduced significantly. Compared to existing works, the proposed strategies are standard-compatible and require no additional side information, like location, map, or vision, making them easier to implement and of low complexity. Moreover, the proposed user-side strategies are more flexible than the base station (BS)-side methods, especially for beam switching/handover between BSs. Numerical results on both statistical and ray-tracing blockage channel models are provided to demonstrate the superiority of the proposed algorithms.