Revisiting LTE LAA: Channel Access, QoS, and Coexistence with WiFi

TL;DR

This paper clarifies LTE LAA's channel access and QoS mechanisms, evaluates its coexistence with WiFi, and discusses future research challenges in unlicensed bands.

Contribution

It provides an updated analysis of LTE LAA's operation aligned with current standards and experimentally assesses its impact on WiFi performance.

Findings

LAA's channel access methods are clarified and aligned with standards.

Experimental results show LAA's QoS settings affect WiFi performance.

Future research challenges in LTE unlicensed band coexistence are outlined.

Abstract

Network operators are looking towards LTE License Assisted Access (LAA) as a means of extending capacity by offloading traffic to unlicensed bands. However, operation in these bands requires abiding to certain coexistence rules in terms of channel access. The description of these rules in existing literature is not always in line with the latest standards. Therefore, in this paper, we clarify the operation of LAA, focusing on channel access and methods of providing Quality of Service (QoS) support. In terms of coexistence, we evaluate the impact of LAA under its various QoS settings on Wi-Fi performance in an experimental testbed. Finally, we describe the upcoming research challenges for LTE-based technologies in unlicensed bands considering the latest developments.