Machine learning based scheme for contention window size adaptation in LTE-LAA

Ali, Zoraze; Giupponi, Lorenza; Mangues‐Bafalluy, Josep; Bojović, Biljana

doi:10.1109/pimrc.2017.8292751

Cited by 25 publications

(16 citation statements)

References 8 publications

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“…On the other hand, Wi-Fi increases its CW size when an Acknowledgment (ACK) or a Block Acknowledgment (BA) for the packet/s transmitted to a single user is not received. The Wi-Fi CW update scheme is then considering equally the feedback coming from different Wi-Fi Station (STA)s. This difference can cause that under specific conditions LAA updates the CW significantly less often than Wi-Fi [35].…”

Section: Cw Updatementioning

confidence: 99%

“…For example, if the sender does not receive an ACK before the timeout expires, it will usually retransmit the frame/packet until the sender receives an ACK or exceeds a predefined number of retransmissions. Therefore, due to the efficiency of a soft combining technique used in the LTE HARQ procedure, it may happen that, Wi-Fi detects more collisions than LAA, and consequently it increases the CW more often [35].…”

Section: E Collision Detection Mechanismmentioning

confidence: 99%

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Evaluating Unlicensed LTE Technologies: LAA vs LTE-U

et al. 2019

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Recently, there has been much interest by the cellular network industry in utilizing unlicensed spectrum to expand potential capacity. In particular, two LTE unlicensed technologies gained much attention: licensed-assisted access (LAA) and LTE unlicensed (LTE-U). While these are rapidly entering the market, there are not many studies in the literature that are providing a complete evaluation and comparison of their performance. Available work usually focuses on single technology standalone evaluations. Also, despite the vast body of simulation results by industry and academia, the simulators are not publicly available, and the analytical models proposed in the literature do not offer complex enough frameworks for thorough performance evaluations. To carry out an evaluation study, we have built a comprehensive simulation platform, strictly complying with the standards and specifications of each technology. The models are built upon popular ns-3 simulator, have been designed in close consultation with industry experts, and have been validated through calibration processes and against analytical proposals and experimental platforms. In this paper, we provide a detailed overview, performance evaluation, and comparison of LAA and LTE-U in a wide variety of scenarios, following 3GPP and Wi-Fi Alliance (WFA) guidelines. We show that despite the market is confirming LAA as the leading unlicensed LTE technology, in certain setups, efficient implementations of LTE-U may prove unexpectedly better in coexisting with Wi-Fi. Similarly, the expected behaviors of the LAA LBT procedure can reveal untrue, depending on the traffic or interference patterns and specific implementation details, even in Wi-Fi. This paper also includes scenarios involving TCP, which is a rarely treated topic in the literature in the context of LTE and Wi-Fi coexistence. The end-to-end and full protocol stack simulation platform is openly available to foster results' reproducibility and collaborative development.

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Section: Cw Updatementioning

confidence: 99%

Section: E Collision Detection Mechanismmentioning

confidence: 99%

Evaluating Unlicensed LTE Technologies: LAA vs LTE-U

et al. 2019

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“…When the channel is free, another eCCA period (e.g., 9µs) begins and N is decreased by one if the channel is clear. When N decrements to zero, the LAA eNB starts the transmission for a fixed configurable Transmission Opportunity (TxOP) time, which can be up to 10 ms depending on the channel access priority class (see Table 2 There are a few drawbacks of the 3GPP Cat 4 algorithm which considers the HARQ feedbacks to update the LAA CW [38], [39]. In particular, the LAA CW size will not be updated if less than 80% of the users suffer from the collision since the collision remains undetected below this threshold.…”

Section: B Lte-laa Technologymentioning

confidence: 99%

Novel LAA Waiting and Transmission Time Configuration Methods for Improved LTE-LAA/Wi-Fi Coexistence Over Unlicensed Bands

Alhulayil

López-Benítez

2020

IEEE Access

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Long Term Evolution-Licensed Assisted Access (LTE-LAA) has been pointed out as a key solution to cope with the increasing amounts of data traffic and the scarcity of the licensed spectrum. The 3rd Generation Partnership Project (3GPP) has standardised LAA to operate over the 5 GHz unlicensed spectrum which is mainly occupied by Wi-Fi. It is a challenging problem to ensure a fair coexistence between these technologies. Several studies have been proposed in the literature to allow a fair LAA/Wi-Fi coexistence. In this work, various methods are proposed to adapt/select the waiting times for LAA based on the activity statistics of the existing Wi-Fi network. The main novelty is that the knowledge of the existing Wi-Fi activities is exploited to tune the boundaries of the Contention Window (CW) for LAA and to select fixed waiting times for LAA. Moreover, a dynamic method is proposed to adapt the Transmission Opportunity (TxOP) times for LAA based on the Hybrid Automatic Repeat Request (HARQ) feedbacks. The methods are evaluated using ns-3 network simulator based on the 3GPP fairness definition. We show that selecting fixed waiting times for LAA based on the existing Wi-Fi activities is more friendly to the existing Wi-Fi and provides better total aggregated throughputs for both coexisting networks compared to the 3GPP Category 4 Listen Before Talk (Cat 4 LBT) algorithm. Moreover, the proposed dynamic TxOP method is more friendly to the existing Wi-Fi and provides better total aggregated throughputs compared to the fixed TxOP period approach of the 3GPP Cat 4 LBT scheme. INDEX TERMS Licensed assisted access, LTE/Wi-Fi coexistence, ns-3, Unlicensed spectrum, Wi-Fi.

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“…Ali et al [39] propose a NN based approach that adapts LBT's CW size based on the predicted number of Negative Acknowledgments (NACKs) for all subframes in a Channel Occupancy Time (COT) of LTE-LAA. The correct configuration of the CW size is of utmost importance to avoid collisions or to resolve contention among colliding radios.…”

Section: Related Workmentioning

confidence: 99%

A Spectrum Sharing Framework for Intelligent Next Generation Wireless Networks

Figueiredo¹,

Mennes²,

Jiao³

et al. 2018

Preprint

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The explosive emergence of wireless technologies and standards, covering licensed and unlicensed spectrum bands has triggered the appearance of a huge amount of wireless technologies, with many of them coexisting in the same band. Unfortunately, the wireless spectrum is a scarce resource, and the available frequency bands will not scale with the foreseen demand for new capacity. Certain parts of the spectrum, in particular the license-free ISM bands, are overcrowded, while other parts, mostly licensed bands, may be significantly underutilized. As such, there is a need to introduce more advanced techniques to access and share the wireless medium, either to improve the coordination within a given band, or to explore the possibilities of intelligently using unused spectrum in underutilized (e.g., licensed) bands. Therefore, in this paper, we present an open source SDR-based framework that can be employed to devise disruptive techniques to optimize the sub-optimal use of radio spectrum that exists today. Additionally, we describe three use cases where the proposed framework can be employed along with intelligent algorithms to achieve improved spectrum utilization.

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Machine learning based scheme for contention window size adaptation in LTE-LAA

Cited by 25 publications

References 8 publications

Evaluating Unlicensed LTE Technologies: LAA vs LTE-U

Evaluating Unlicensed LTE Technologies: LAA vs LTE-U

Novel LAA Waiting and Transmission Time Configuration Methods for Improved LTE-LAA/Wi-Fi Coexistence Over Unlicensed Bands

A Spectrum Sharing Framework for Intelligent Next Generation Wireless Networks

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