Performance Modeling of an LTE LAA and WiFi Coexistence System Using the LAA Category-4 LBT Procedure and 802.11e EDCA Mechanism

Zheng, Jun; Xiao, Jie; Ren, Qilei; Zhang, Yuan

doi:10.1109/tvt.2020.2984693

Cited by 18 publications

(12 citation statements)

References 16 publications

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“…There are many works to analyze the performance of the coexistence for WiFi and LAA [13]- [20]. [13] addresses that downlink capacity degradation of WiFi is more severe than LAA in simulations when they operate in the same frequency band.…”

Section: B Related Workmentioning

confidence: 99%

“…Their numerical results demonstrate effects of various system parameters. [20] takes into account transmission priorities and the gap period problem in a coexistence system using the LAA Cat.4 LBT procedure and 802.11e enhanced distributed channel access mechanism under an unsaturated condition. They propose a reservation signal to filling in the gap so that the system performance can be significantly improved.…”

Section: B Related Workmentioning

confidence: 99%

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Listen Before Receive (LBR) Assisted Network Access in LAA and WiFi Heterogeneous Networks

et al. 2021

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The Listen-Before-Talk (LBT) is the main procedure for Licensed Assisted Access (LAA) to accomplish fair and friendly coexistence with other operators or technologies operating over unlicensed spectrum. However, in LBT, the lack of coordination with other existing systems brings challenges in sustaining performance in the coexistence of LAA and WiFi networks. Specifically, the hidden node problem (HNP) and exposed node problem (ENP) cannot be effectively handled when both LAA and WiFi nodes attempt to access the unlicensed spectrum at the same time. Thus, transmission failure might occur and the network performance would be degraded. In order to mitigate the influences caused by HNP and ENP, based on LBT, we firstly analyze HNP and ENP by means of mathematical approach. The analytical results surprisingly reveal that the hidden node and exposed node probabilities are as high as 41% and 39.33%, respectively. Then, a Give And p-persistent Take (GAT) mechanism with the Listen-Before-Receive (LBR) procedure, namely LBR-GAT, is proposed to cope with LBT to reduce the collision caused by HNP as well as to retrieve the bandwidth sacrificed by the ENP. With LBR-GAT, the LAA sender conditionally gives up or takes back transmission opportunities, and thus the unlicensed spectrum could be efficiently shared between LAA and WiFi. Evaluation results show that the proposed LBR-GAT could conditionally obtain better network performance comparing to legacy LBT.

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Section: B Related Workmentioning

confidence: 99%

Section: B Related Workmentioning

confidence: 99%

Listen Before Receive (LBR) Assisted Network Access in LAA and WiFi Heterogeneous Networks

et al. 2021

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“…4.1. Challenge 1: LBT Is Mandatory to Operate in the Unlicensed or Shared Band "Listen before talk" has been designed to ensure a better neighbor to WiFi while coexisting in the unlicensed band [41]. However, the presence of LBT in channel access, characterized by a decentralized and asynchronous random access to the radio channel for uplink data transmission, can highly degrade NR-U performance in terms of channel access delay and latency due to the LBT requirement for each new transmission.…”

Section: Challenges and Research Directionsmentioning

confidence: 99%

Future Is Unlicensed: Private 5G Unlicensed Network for Connecting Industries of Future

Bajracharya

Shrestha

Jung

2020

Sensors

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This paper aims to unlock the unlicensed band potential in realizing the Industry 4.0 communication goals of the Fifth-Generation (5G) and beyond. New Radio in the Unlicensed band (NR-U) is a new NR Release 16 mode of operation that has the capability to offer the necessary technology for cellular operators to integrate the unlicensed spectrum into 5G networks. NR-U enables both uplink and downlink operation in unlicensed bands, supporting 5G advanced features of ultra-high-speed, high bandwidth, low latency, and improvement in the reliability of wireless communications, which is essential to address massive-scale and highly-diverse future industrial networks. This paper highlights NR-U as a next-generation communication technology for smart industrial network communication and discusses the technology trends adopted by 5G in support of the Industry 4.0 revolution. However, due to operation in the shared/unlicensed spectrum, NR-U possesses several regulatory and coexistence challenges, limiting its application for operationally intensive environments such as manufacturing, supply chain, transportation systems, and energy. Thus, we discuss the significant challenges and potential solution approaches such as shared maximum channel occupancy time (MCOT), handover skipping, the self-organized network (SON), the adaptive back-off mechanism, and the multi-domain coexistence approach to overcome the unlicensed/shared band challenges and boost the realization of NR-U technology in mission-critical industrial applications. Further, we highlight the role of machine learning in providing the necessary intelligence and adaptation mechanisms for the realization of industrial 5G communication goals.

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“…Simply waiting for the next slot boundary may result in losing channel access if Wi-Fi stations start transmission before the next slot boundary. Thereby it entails low LTE-LAA performance [6], [7]. For this reason, many research papers [6]- [11] imply that a base station sends a reservation signal until the next slot boundary.…”

Section: Introductionmentioning

confidence: 99%

“…At the same time, it causes excessive overhead and dramatically reduces the performance of Wi-Fi networks [7], [10], [12].…”

Section: Introductionmentioning

confidence: 99%

Enhanced Collision Resolution Methods With Mini-Slot Support for 5G NR-U

et al. 2021

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To improve the capacity of cellular systems without additional expenses on licensed frequency bands, the 3GPP consortium has designed cellular technologies that use the unlicensed spectrum. The important peculiarity of the usage models of these technologies, the latest of which is New Radio Unlicensed (NR-U), is the coexistence with Wi-Fi networks deployed in the same frequency band. That is why NR-U uses channel access methods similar to those of Wi-Fi. However, the performance of Wi-Fi networks notably deteriorates in coexistence scenarios. One of the reasons is the slotted structure of transmissions of cellular base stations in the unlicensed spectrum, which may imply the use of a reservation signal. The paper proposes two novel channel access methods for NR-U, in which an NR-U base station randomly stops sending the reservation signal to listen to the channel to detect and resolve collisions. Analytical models are developed to validate the proposed methods and evaluate their efficiency, taking into account important features of NR-U networks, such as flexible numerology and mini-slot transmissions. The obtained numerical results show that the proposed methods significantly improve the performance of the Wi-Fi or NR-U network without degradation of the throughput of the other technology in coexistence scenarios.

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Performance Modeling of an LTE LAA and WiFi Coexistence System Using the LAA Category-4 LBT Procedure and 802.11e EDCA Mechanism

Cited by 18 publications

References 16 publications

Listen Before Receive (LBR) Assisted Network Access in LAA and WiFi Heterogeneous Networks

Listen Before Receive (LBR) Assisted Network Access in LAA and WiFi Heterogeneous Networks

Future Is Unlicensed: Private 5G Unlicensed Network for Connecting Industries of Future

Enhanced Collision Resolution Methods With Mini-Slot Support for 5G NR-U

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