Enhanced listen-before-talk scheme for frequency reuse of licensed-assisted access using LTE

Abstract

Licensed-Assisted Access (LAA) using Long Term Evolution (LTE) is a promising solution to alleviate the problem of scarce spectrum resources by extending to the unlicensed band. However, co-existence mechanisms should be carefully taken into consideration to provide fair co-existence to other LAA and 802.11 based Wi-Fi networks that operate on the same unlicensed carrier. In this paper, we focus on the design of listen-before-talk (LBT) for the LAA system and provide insights into the impact of LAA clear channel assessment (CCA) threshold on the trade-off between frequency reuse and interference avoidance. Moreover, an enhanced LBT scheme is proposed by adaptively adjusting the LAA CCA threshold to exploit the benefits of frequency reuse for LAA while guaranteeing the fair co-existence with Wi-Fi at the same time. System-level simulation is performed to analyze the CCA threshold among LAA networks and evaluate the effectiveness of the proposed LBT scheme compared to that with fixed CCA threshold. It is shown that significant performance gains can be achieved for LAA by using the proposed LBT scheme under efficient protection of Wi-Fi performance.