Enhanced network sensitive access control scheme for LTE–LAA/WiFi coexistence: Modeling and performance analysis

Implementation of 5G and beyond networks is looking to expand the operation of licensed systems into unlicensed frequency bands through technologies such as license assisted access (LAA) and New Radio Unlicensed (NR-U). LAA aggregates licensed and unlicensed bands for long term evolution (LTE) imple...

Full description

Saved in:
Bibliographic Details
Published in:Computer communications 2021-04, Vol.172, p.45-53
Main Authors: Saadat, Salman, Ejaz, Waleed, Hassan, Shahzad, Bari, Inam, Hussain, Tariq
Format: Article
Language:English
Subjects:
Coexistence
License assisted access
Listen before talk
LTE
Unlicensed band
WiFi
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Implementation of 5G and beyond networks is looking to expand the operation of licensed systems into unlicensed frequency bands through technologies such as license assisted access (LAA) and New Radio Unlicensed (NR-U). LAA aggregates licensed and unlicensed bands for long term evolution (LTE) implementation to address the ever-increasing demand for cellular data traffic and shortage of licensed spectrum. Spectrum-efficient resource-sharing schemes are, however, critical for the harmonious coexistence of LTE–LAA with incumbent systems on the unlicensed band, especially WiFi, while opportunistically improving LTE throughput and enhancing spectrum utilization of the unlicensed band. In this paper, we present a listen before talk (LBT) based clear channel assessment (CCA) mechanism for LAA eNodeBs (eNBs) to improve the coexistence performance of LTE–LAA with WiFi. Particularly, we propose an adaptive exponential backoff scheme for LTE eNB that dynamically updates the contention window (CW) size and transmission opportunity (TXOP) parameters according to network load variations. A three-dimensional discrete Markov model is developed to describe the LBT procedure of LAA eNB, and a performance model is further derived to evaluate steady-state channel access, transmission, and failure probabilities. The proposed scheme’s performance is evaluated in terms of successful transmission probability, throughput, and delay according to the 3GPP and WiFi guidelines. The results are compared with the traditional schemes proposed in literature considering fixed and adaptive CW size for LAA eNB.
ISSN:0140-3664
1873-703X
DOI:10.1016/j.comcom.2021.03.003