DRX in NR Unlicensed for B5G Wireless: Modeling and Analysis

The proliferation in the demand of high data rate and improved performance has urged the wireless vendors to think of extending 5G New Radio (NR) in unlicensed bands. The unlicensed band is typically used by Wi-Fi/Wi-Gig, resulting in the reduced probability of the availability of channel for transmission of data. The User Equipment (UE) has to keep its radio circuitry ON and wait until it gets access to the unlicensed channel again. This process escalates the energy expense of the battery-constrained mobile devices. Discontinuous Reception (DRX) introduced in LTE and 5G can also be used in NR-Unlicensed (NR-U) to reduce the UE's energy consumption. In this article we introduce a DRX mechanism over NR-U networks for both Standalone (SA) and Non-Standalone (NSA) deployment modes. We used two different flavors, Beam-Search and Beam-Aware, to model the DRX mechanism. Hence, the proposed DRX mechanisms are: Standalone DRX with Beam-Search (SBS-DRX), Standalone DRX with Beam-Aware (SBA-DRX), Non-Standalone DRX with Beam-Search (NBS-DRX), and Non-Standalone DRX with Beam-Aware (NBA-DRX). Semi-Markov based modeling is used to show the estimation of power-saving, average delay, and resource utilization in the proposed NR-U DRX mechanism. Mathematical analysis and simulation results indicate that DRX in NR-U significantly improves the UE's power-saving, average delay, and resources utilized by the network. The power-saving achieved with SBA-DRX is 21:13% and 24:84% higher than 5G NR DRX for both Trace 1 and Trace 2, respectively. Moreover, the delay achieved with NBA-DRX is 19:16% less than NBS-DRX with 18% less resource utilization.