Performance Modeling of an NR-U and WiFi Coexistence System Using the NR-U Category-4 LBT Procedure and WiFi DCF Mechanism in the Presence of Hidden Nodes

Abstract

The hidden-node problem is an important problem that should be considered in the design of a wireless communication system. This paper studies the performance modeling of an NR-U and WiFi coexistence system using the NR-U category-4 LBT procedure and WiFi DCF mechanism in the presence of hidden nodes. 2-D Markov models are first developed to describe the NR-U category-4 LBT procedure of an NR-U gNB and the WiFi DCF procedure of a WiFi AP, respectively, taking into account the effects of hidden nodes. Based on the two Markov models, theoretical models are further derived for analyzing the throughput of a gNB/AP and the delay of an NR-U/WiFi packet. Finally, the derived theoretical models are validated through simulation results and based on the theoretical models, the impacts of major system parameters on the system performance in terms of the throughput and packet delay are investigated, including the data packet arrival rate, the density, the sensing distance, and the channel transmission rate of a gNB.