A novel coexistence scheme for IEEE 802.11 for user fairness and efficient spectrum utilization in the presence of LTE-U
A novel coexistence scheme for IEEE 802.11 for user fairness and efficient spectrum utilization in the presence of LTE-U
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DOI：
10.1016/j.comnet.2018.04.002
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发表时间：
2018-07
期刊：
影响因子：
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通讯作者：
Anand M. Baswade;Touheed Anwar Atif;T. B. Reddy;A. Franklin
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文献类型：
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作者：
Anand M. Baswade;Touheed Anwar Atif;T. B. Reddy;A. Franklin
占空比 LTE-U 方案是一种很有前途的解决方案，可以满足业界对 LTE 在免许可频谱上运行进行最小修改的需求，该方案采用不连续传输来确保与 802.11 (Wi-Fi) WLAN 的公平共存。尽管该方案保证维持Wi-Fi网络性能，但Wi-Fi用户之间的公平性仍然是个谜。在这项工作中，我们提出了一个实际场景，其中 LTE-U 尽管不连续（遵循开/关循环），但不仅会导致 Wi-Fi 用户之间的吞吐量分配不公平，还会导致 Wi-Fi AP 下行链路性能下降。这是由于少数 Wi-Fi 用户在 LTE-U 开启和关闭期间利用信道（即非受害者用户）占主导地位，而那些仅在关闭期间获得访问权限的用户（称为受害者用户）占主导地位。在本文中，我们研究了受害和非受害 Wi-Fi 用户以及 Wi-Fi AP 在改变 LTE-U ON 比例（即占空比）时的性能。考虑到易于实现，针对WLAN提出了一种有利的方案，采用802.11的点/混合协调功能(PCF/HCF)模式，保证Wi-Fi用户之间的公平性，同时提高Wi-Fi网络的信道利用率。其关键思想是，只能在 LTE-U OFF 期间才能获得服务的受害用户应该在无竞争期 (CFP) 中得到服务，从而提高其吞吐量并使其与非受害用户具有同等竞争力。此外，我们还提出了一个分析模型来证明有保证的改进并验证我们的模拟结果。
A promising solution satisfying the industry’s demand to have minimum modification in LTE for its operation in unlicensed spectrum is duty cycled LTE-U scheme, which adopts discontinuous transmission to ensure fair coexistence with 802.11 (Wi-Fi) WLANs. Even though the scheme guarantees to maintain Wi-Fi network performance, the fairness among Wi-Fi users still remains arcane. In this work, we present a practical scenario where LTE-U, despite being discontinuous (by following an ON/OFF cycle), results in not only unfair throughput distribution among Wi-Fi users but also causes degradation in Wi-Fi AP’s downlink performance. This is due to the domination of few Wi-Fi users who harness channel in both ON and OFF durations of LTE-U, namely non-victim users over those who get access only in OFF duration, called victim users. In this paper, we studied the performance of victim and non-victim Wi-Fi users, and Wi-Fi AP while varying LTE-U ON fraction (i.e.,duty cycle). A propitious scheme is proposed for WLANs, with regard to ease of implementation, employing Point/Hybrid Coordination Function (PCF/HCF) mode of 802.11, promising fairness among Wi-Fi users with improvement in the channel utilization of Wi-Fi network. The key idea is that the victim users, who can only be served during the LTE-U OFF period should be served in Contention Free Period (CFP)—so as to improve their throughputs and make them equally competitive with non-victim users. Also, we present an analytical model to demonstrate guaranteed improvement and to validate our simulation results.