Frame-based listen-before-talk (FB-LBT) has been adopted as one of the channel access mechanism for Wi-Fi/LTE coexistence. We aim to explore the limits of FB-LBT by developing theoretical models to characterize the FB-LBT channel access performance under the coexistence of LTE and Wi-Fi. We first derive a steady-state model to calculate the spectrum share occupied by LTE under the assumption that the Wi-Fi transmissions have stationary distributions. The assumption does not hold when the time between two LTE transmissions is short, where the system is dominated by a dynamic phenomenon. A second model is developed that accounts for the dynamics of the Wi-Fi channel access mechanism. Our models, validated by simulation results, accurately calculate the spectrum share occupied by LTE over a range of FB-LBT frame periods and Wi-Fi traffic loads. We obtain upper bounds on the FB-LBT spectrum share when competing with heavy Wi-Fi traffic, which confirm the weakness of FB-LBT. Moreover, we demonstrate that our models can be used to control the FB-LBT spectrum share within a modest range.

中文翻译：

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基于帧的 Listen-Before-Talk 的共存性能和限制

基于帧的先听后谈 (FB-LBT) 已被用作 Wi-Fi/LTE 共存的信道接入机制之一。我们旨在通过开发理论模型来表征 LTE 和 Wi-Fi 共存下的 FB-LBT 信道访问性能，从而探索 FB-LBT 的局限性。我们首先推导出一个稳态模型来计算在 Wi-Fi 传输具有平稳分布的假设下 LTE 占用的频谱份额。当两次 LTE 传输之间的时间很短时，假设不成立，此时系统受动态现象支配。开发了第二种模型，用于说明 Wi-Fi 通道访问机制的动态。我们的模型经过仿真结果验证，可以准确计算 LTE 在一系列 FB-LBT 帧周期和 Wi-Fi 流量负载范围内占用的频谱份额。我们在与大量 Wi-Fi 流量竞争时获得了 FB-LBT 频谱份额的上限，这证实了 FB-LBT 的弱点。此外，我们证明我们的模型可用于在适度范围内控制 FB-LBT 频谱份额。