LTE-U系统的容量分析和用户驻留研究
发布时间：2019-07-07 07:23
【摘要】：近年来,随着移动智能设备的飞速发展,无线用户数量呈指数倍增长,人们对无线通信的需求也不断增大,有限的许可频段资源已经越来越无法满足人们的需求。在这种状况下,有人提出将LTE(Long Term Evolution Unlicensed)技术应用于免许可频段,即免许可频段LTE(Long Term Evolution Unlicensed,LTE-U)技术。通过利用LTE技术的优势提高免许可频段的频谱利用率,以此来分担许可频段的压力。本文对LTE-U网络的容量和用户驻留进行了深入研究。首先,研究了 LTE-U网络在支持时延敏感业务时的网络容量。我们用离散马尔科夫链来对采用轮询调度策略的LTE-U系统的传输机会进行建模,通过概率生成函数和泊松网格算法计算得到马尔科夫链的状态转移概率。基于时延敏感业务的两个服务质量(Quality of Service,QoS)要求——最大容忍时延和丢包率门限,得到LTE-U网络在支持时延敏感业务时的网络容量。仿真结果表明我们所提出的分析模型不仅可以有效评估LTE-U网络与不同负载的Wi-Fi(Wireless Fidelity)网络共存时的网络容量,而且也揭示了其网络容量与时延敏感业务的两个QoS指标要求之间的关系。其次,研究了多信道场景中采用信道绑定技术的LTE-U网络的性能。以吞吐量为性能指标,我们提出了一种将主信道和辅信道分开独立建模的分析方法。该分析方法根据信道被占用的情况将信道分为四种状态,利用不同状态出现的概率以及持续时间求出不同状态的时间占比,从而分别得到LTE-U网络和Wi-Fi网络的吞吐量。仿真结果不仅表明该分析方法的有效性,而且还揭示了 LTE-U网络吞吐量与主辅信道上Wi-Fi网络负载之间的关系。最后,研究了 LTE-U独立系统的用户驻留流程及小区选择准则。为了缓解LTE小区的压力,我们提出了让用户优先驻留LTE-U小区的思想,即通过让用户优先搜索LTE-U小区来提高LTE-U小区的优先级。在搜索LTE-U小区和同步过程中,为了避免用户因为LTE-U小区的信道非连续可用而延长其完成驻留的时间,我们使用了一个基于LTE-U小区相邻两次接入信道的平均时间间隔的同步计时器。另外,我们提出了一种新的小区选择准则——在考虑小区参考信号接收功率强度的同时结合LTE-U独立系统基站相邻两次接入信道的平均时间间隔,通过计算剩余有效容量和剩余吞吐量来进行小区选择。此外,该准则从用户侧出发,在用户的历史业务数据中挖掘出对小区选择有用的信息,从而使用户能够做出更加合适的小区选择决策,提高用户成功发起业务的概率,降低用户小区重选的频率以及小区重选所带来的资源消耗。
文内图片：
图片说明：图１．１邋ＬＴＥ－Ｕ系统逡逑１．２国内外研究现状逡逑
[Abstract]:In recent years, with the rapid development of mobile intelligent devices, the number of wireless users is exponential growth, the demand for wireless communication is also increasing, the limited licensed frequency band resources have become more and more unable to meet the needs of people. In this case, some people propose to apply LTE (Long Term Evolution Unlicensed) technology to license-free frequency band, that is, license-free frequency band LTE (Long Term Evolution Unlicensed,LTE-U) technology. By making use of the advantages of LTE technology to improve the spectrum efficiency of the licensed frequency band, so as to share the pressure of the licensed frequency band. In this paper, the capacity and user residence of LTE-U network are deeply studied. Firstly, the network capacity of LTE-U network when supporting delay-sensitive traffic is studied. We use discrete Markov chain to model the transmission opportunity of LTE-U system with polling scheduling strategy, and calculate the state transition probability of Markov chain by probability generation function and Poisson grid algorithm. Based on the two quality of service (Quality of Service,QoS) requirements of delay-sensitive services, the maximum tolerance delay and packet loss rate threshold are obtained, and the network capacity of LTE-U networks supporting delay-sensitive services is obtained. The simulation results show that the proposed analysis model can not only effectively evaluate the network capacity of LTE-U network and Wi-Fi (Wireless Fidelity) network with different loads, but also reveal the relationship between the network capacity and the two QoS index requirements of delay-sensitive traffic. Secondly, the performance of LTE-U network using channel binding technology in multi-channel scenario is studied. Taking throughput as the performance index, we propose an analysis method to separate the primary channel from the auxiliary channel. According to the occupation of the channel, the channel is divided into four states. The time ratio of different states is calculated by using the probability and duration of different states, and the throughput of LTE-U network and Wi-Fi network are obtained respectively. The simulation results not only show the effectiveness of the analysis method, but also reveal the relationship between LTE-U network throughput and Wi-Fi network load on primary and secondary channels. Finally, the user residence process and cell selection criteria of LTE-U independent system are studied. In order to relieve the pressure of LTE cell, we put forward the idea of letting users stay in LTE-U cell first, that is, to improve the priority of LTE-U cell by letting users search LTE-U cell first. In the process of searching LTE-U cells and synchronizing, in order to prevent users from prolonging their residence time because the channels of LTE-U cells are not continuously available, we use a synchronization timer based on the average time interval of two adjacent access channels in LTE-U cells. In addition, we propose a new cell selection criterion, which takes into account the received power intensity of the cell reference signal and combines the average time interval of the adjacent two access channels of the base station of the LTE-U independent system to select the cell by calculating the remaining effective capacity and residual throughput. In addition, the criterion excavates useful information for cell selection from the user's historical service data, so that the user can make more suitable cell selection decision, improve the probability of the user successfully initiating the service, reduce the frequency of the user cell reselection and the resource consumption caused by the cell reselection. the user can make a more suitable cell selection decision, improve the probability of the user successfully initiating the service, and reduce the frequency of the user cell reselection and the resource consumption caused by the cell reselection.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.5
本文编号：2511365
文内图片：
图片说明：图１．１邋ＬＴＥ－Ｕ系统逡逑１．２国内外研究现状逡逑
[Abstract]:In recent years, with the rapid development of mobile intelligent devices, the number of wireless users is exponential growth, the demand for wireless communication is also increasing, the limited licensed frequency band resources have become more and more unable to meet the needs of people. In this case, some people propose to apply LTE (Long Term Evolution Unlicensed) technology to license-free frequency band, that is, license-free frequency band LTE (Long Term Evolution Unlicensed,LTE-U) technology. By making use of the advantages of LTE technology to improve the spectrum efficiency of the licensed frequency band, so as to share the pressure of the licensed frequency band. In this paper, the capacity and user residence of LTE-U network are deeply studied. Firstly, the network capacity of LTE-U network when supporting delay-sensitive traffic is studied. We use discrete Markov chain to model the transmission opportunity of LTE-U system with polling scheduling strategy, and calculate the state transition probability of Markov chain by probability generation function and Poisson grid algorithm. Based on the two quality of service (Quality of Service,QoS) requirements of delay-sensitive services, the maximum tolerance delay and packet loss rate threshold are obtained, and the network capacity of LTE-U networks supporting delay-sensitive services is obtained. The simulation results show that the proposed analysis model can not only effectively evaluate the network capacity of LTE-U network and Wi-Fi (Wireless Fidelity) network with different loads, but also reveal the relationship between the network capacity and the two QoS index requirements of delay-sensitive traffic. Secondly, the performance of LTE-U network using channel binding technology in multi-channel scenario is studied. Taking throughput as the performance index, we propose an analysis method to separate the primary channel from the auxiliary channel. According to the occupation of the channel, the channel is divided into four states. The time ratio of different states is calculated by using the probability and duration of different states, and the throughput of LTE-U network and Wi-Fi network are obtained respectively. The simulation results not only show the effectiveness of the analysis method, but also reveal the relationship between LTE-U network throughput and Wi-Fi network load on primary and secondary channels. Finally, the user residence process and cell selection criteria of LTE-U independent system are studied. In order to relieve the pressure of LTE cell, we put forward the idea of letting users stay in LTE-U cell first, that is, to improve the priority of LTE-U cell by letting users search LTE-U cell first. In the process of searching LTE-U cells and synchronizing, in order to prevent users from prolonging their residence time because the channels of LTE-U cells are not continuously available, we use a synchronization timer based on the average time interval of two adjacent access channels in LTE-U cells. In addition, we propose a new cell selection criterion, which takes into account the received power intensity of the cell reference signal and combines the average time interval of the adjacent two access channels of the base station of the LTE-U independent system to select the cell by calculating the remaining effective capacity and residual throughput. In addition, the criterion excavates useful information for cell selection from the user's historical service data, so that the user can make more suitable cell selection decision, improve the probability of the user successfully initiating the service, reduce the frequency of the user cell reselection and the resource consumption caused by the cell reselection. the user can make a more suitable cell selection decision, improve the probability of the user successfully initiating the service, and reduce the frequency of the user cell reselection and the resource consumption caused by the cell reselection.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.5
【参考文献】
相关期刊论文 前2条
1 彭丽;张纯波;;LTE-U技术及发展浅析[J];数据通信;2016年01期
2 孙波;钟征斌;;非授权载波上的黑马——LTE-U[J];硅谷;2014年16期
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