Design and Analysis of Random Access for Standalone LTE-U Systems
Design and Analysis of Random Access for Standalone LTE-U Systems
复制标题
独立 LTE-U 系统随机接入的设计与分析
DOI：
10.1109/tvt.2018.2847301
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发表时间：
2018-10
影响因子：
6.8
通讯作者：
ing
中科院分区：
文献类型：
--
作者：
Yuan Jiantao;Huang Aiping;Shan Hangguan;Quek Tony Q. S.;Yu Gu;ing
与长期演进（long-term evolution， LTE）系统垄断许可信道不同，非许可频谱中的独立LTE系统（SA LTE- u）不允许不间断地占用非许可信道，不能预先确定其占用信道的起始点，并限制其最大信道占用时间。因此，在随机存取（RA）过程中，用户设备可能会在信道占用时间内出现积压，从而在信道占用时间内造成严重的碰撞，导致SA LTE-U系统的序文不必要的重传。为了解决上述问题，我们提出了一种基于用户分组和有效窗口大小的RA协议。该协议将终端划分为若干组，在任何时候，只有一个组被激活并允许其终端发送RA尝试，从而避免了组间终端的冲突。激活组的积压终端分散在多个RA插槽中发送RA尝试，缓解了组内终端的冲突。此外，为了避免由于信道不确定性导致的不必要的序文重传，RA尝试的发送和RA响应的接收都在仅由信道占用期组成的有效信道上进行。导出了传输成功率和丢弃率、前置传输次数累积分布函数、承载RA时隙利用率和RA延迟的表达式。为了获得最优的承载RA槽数，提出了承载RA槽利用率最大化的优化问题。仿真结果表明，该协议在SA LTE-U系统中优于基线协议。
Different from a long-term evolution (LTE) system that monopolizes a licensed channel, the standalone LTE system in an unlicensed spectrum (SA LTE-U) is not allowed to occupy the unlicensed channel uninterruptedly, the starting point of its channel occupancy cannot be determined in advance, and its maximum channel occupancy time is restricted. Therefore, user equipments (UEs) may be backlogged during the channel unoccupancy time in their random access (RA) procedure, which causes severe collision during the channel occupancy time and unnecessary retransmissions of preambles in an SA LTE-U system. To address the aforesaid issues, we propose a user grouping and effective window size based RA protocol. In this protocol, the UEs are divided into several groups, and at any time only one group is activated and allowed for its UEs to send RA attempt, which avoids the intergroup UEs’ collision. The backlogged UEs of the activated group are scattered over multiple RA slots for them to send RA attempt, which alleviates the intragroup UEs’ collision. In addition, to avoid the unnecessary retransmissions of preambles caused by the channel uncertainty, the transmission of RA attempt and the reception of RA response are performed on the effective channel that consists of the channel occupancy periods only. The expressions of success and dropping rates, cumulative distribution function of preamble transmission times, utilization of carrying RA slots, and RA delay are derived. An optimization problem is formulated to maximize the utilization of carrying RA slots to obtain the optimal number of carrying RA slots. Simulation results demonstrate that the proposed protocol outperforms the baseline protocol in SA LTE-U systems.
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影响因子：
8.1
作者：
A. Gotsis;Athanasios S. Lioumpas;A. Alexiou
通讯作者：
A. Gotsis;Athanasios S. Lioumpas;A. Alexiou
DOI：
--
发表时间：
2012-03
期刊：
--
影响因子：
--
作者：
C. Cox
通讯作者：
C. Cox
影响因子：
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作者：
Liu Jiamin;Hangguan Shan;Aiping Huang;Jiantao Yuan;Lin X. Cai
通讯作者：
Liu Jiamin;Hangguan Shan;Aiping Huang;Jiantao Yuan;Lin X. Cai
DOI：
10.1109/jsac.2016.2520222
发表时间：
2016-05-01
影响因子：
16.4
作者：
Arouk, Osama;Ksentini, Adlen;Taleb, Tarik
通讯作者：
Taleb, Tarik
影响因子：
6.8
作者：
Wei, Chia-Hung;Cheng, Ray-Guang;Tsao, Shiao-Li
通讯作者：
Tsao, Shiao-Li