Novel Listen-Before-Talk Access Scheme With Adaptive Backoff Procedure for Uplink Centric Broadband Communication

To cater for the data-hungry Internet of Things (IoT) applications, uplink centric broadband communication (UCBC) has been identified as a new service class in the vision of 5.5G, where the unlicensed spectrum has been regarded as a promising solution to boost the uplink capacity. The new radio unlicensed (NR-U) network adopts category-4 (Cat4) listen before talk (LBT) access scheme to exploit the unlicensed spectrum and fairly coexist with the incumbent wireless fidelity (WiFi) network. However, the existing Cat4 LBT access scheme adopts single fixed energy detection (ED) threshold and backoff speed, which cannot adapt to the sophisticated interference and achieve the expected uplink system throughput. To tackle this issue, in this article, we develop a novel Cat4 LBT access scheme with adaptive backoff procedure for UCBC, which includes instantaneous interference level quantification, instantaneous interference level sharing, and backoff speed determination. The results have shown that our proposed adaptive Cat4 LBT scheme achieves over 70% uplink system throughput performance gain where cell throughput of NR-U network rises by over 100%, and cell throughput of WiFi network increases by 25%.