ORLA/OLAA: Orthogonal Coexistence of LAA and WiFi in Unlicensed Spectrum

García‐Saavedra, Andrés; Patras, Paul; Valls, Víctor; Costa‐Pérez, Xavier; Leith, Douglas J.

doi:10.1109/tnet.2018.2876590

Cited by 24 publications

(15 citation statements)

References 42 publications

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“…Authors in [24] optimize LAA transmission time to increase LAA throughput while maintaining the service of WiFi. [25] creates orthogonal transmission blocks for both LAA and WiFi systems. Further, transmission optimization is derived for synchronous and asynchronous (i.e., with alignment to licensed anchor frame boundaries) modes.…”

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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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%

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

et al. 2021

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“…We generated and transmitted a Wi-Fi signal with a USRP, and captured the signal by another USRP acting as either a Wi-Fi device or an LAA device. 6…”

Section: ) Feasibility Checkmentioning

confidence: 99%

Lightweight Wi-Fi Frame Detection for Licensed Assisted Access LTE

et al. 2019

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Licensed assisted access LTE (LAA-LTE) aggregates 5 GHz unlicensed bands with LTE's licensed bands via carrier aggregation, and adopts energy detection (ED)-based clear channel assessment (CCA) for protection of coexisting Wi-Fi devices. Since LAA-LTE requires the ED threshold should be set conservatively in the potential presence of Wi-Fi, the spatial spectrum reuse of the LAA-LTE will be much impaired. Such non-flexible thresholding has been introduced mainly due to ED's incapability of differentiating Wi-Fi frames from LTE frames. As a remedy, this paper proposes a lightweight but effective Wi-Fi frame detection method with which the LAA-LTE devices can capture a Wi-Fi preamble by only using the LAA-LTE's own time domain samples while incurring very small latency. Built upon the proposed method, we also propose the Wi-Fi energy tracking algorithm to identify the duration of a Wi-Fi frame, and a dynamic ED threshold selection algorithm. The proposed schemes were evaluated via the MATLAB simulations and USRP-based experiments, through which their efficacy has been confirmed, e.g., Wi-Fi frame detection probability up to 98.7%. Moreover, via extensive NS-3 based simulations with a multi-cell coexistence topology, we further revealed that the proposed mechanism not only enhances the spatial efficiency of the LAA-LTE achieving up to 23.68% more throughput than the legacy LAA-LTE but also protects coexisting Wi-Fi better. INDEX TERMS Algorithm design and analysis, cellular networks, computer simulation, wireless LAN, LAA-LTE, schmidl-cox detection.

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“…The coexisting of LTE in unlicensed spectrum (LTE-U) and 802.11ac is evaluated in [7]. They show that it fails to fulfill fair coexisting with 802.11ac and proposes two optimal transmission policies.…”

Section: Related Workmentioning

confidence: 99%

3-Sector Cell vs. Omnicell: Cell Sectorization Impact on the Performance of Side-by-Side Unlicensed LTE and 802.11ac Air Interfaces

Mina

Ghani

2019

IEEE Access

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Due to the benefits of networks coexistence, it is common nowadays to equip mobile phones with two types of network interfaces: LTE and 802.11ac. However, using the same 5GHz bandwidth by 802.11ac and LTE in unlicensed spectrum, along with the structural differences of the two networks, result in multiple coexistence limitations and implementation issues. Considering the potential benefits of cell sectorization over the conventional omnicells for improving the performance of LTE users, can they achieve similar improvements in coexisting networks. Moreover, can LTE signals interfere and affect the performance of 802.11ac users coexisting with LTE. In this case, which LTE cell deployment, either omnicell or sectorized cell, has the most impact. Toward addressing these issues, this work proposes a link-level and physical-level model. The model consists of two distinct LTE sites: a conventional omnicell site (360 degrees) and a threesector site (3 × 120 degrees). In addition, the model contains two similar 802.11ac networks, one for each site, to coexist 802.11ac Wi-Fi stations with LTE users. The model is further optimized to include a pure 802.11ac network, dedicated as the baseline. Subsequently, the model is verified in NS3 through various simulation scenarios by means of measuring and quantifying the three-sector, omnicell, and pure 802.11ac networks performances to facilitate resolving any doubt of mobile operators and developers regarding the cell sectorization and coexistence issues. The simulation results indicate that in coexisting networks, LTE users in omnicell sites attain better performance than users in 3-sector sites, while the performance of 802.11ac users varies when different features are combined.

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ORLA/OLAA: Orthogonal Coexistence of LAA and WiFi in Unlicensed Spectrum

Cited by 24 publications

References 42 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

Lightweight Wi-Fi Frame Detection for Licensed Assisted Access LTE

3-Sector Cell vs. Omnicell: Cell Sectorization Impact on the Performance of Side-by-Side Unlicensed LTE and 802.11ac Air Interfaces

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