LTE-A异构网络干扰协调优化策略研究
发布时间：2018-07-17 19:23
【摘要】：目前,新的移动通信系统在宽带化的过程中,所支持的数据数率不断提升,所能够提供的业务类型不断扩展。在业务量激增的情况下,小区内的业务分布会更加不均匀,在一些用户分布比较集中的地方会形成数据业务热点区域。传统的网络拓扑结构一方面很可能会导致处于小区边缘的热点区域内用户的接收SINR较低、QoS严重下降；另一方面也不利于提升系统的频谱效率。针对此问题,3GPP在LTE-A标准中引入了异构网络的概念。在LTE-A异构网络中,针对上述热点区域,将采用Pico和Femto等低功率节点进行小范围同频覆盖从而提升这些区域内用户的QoS。但与此同时,同频组网会在微小区和宏小区之间引入严重的小区间干扰。异构网络复杂的拓扑结构和干扰场景使得传统的小区间干扰协调(ICIC, Inter-Cell Interference Coordination)技术难以适用。因此,必须有针对性的提出增强型ICIC (eICIC, enhanced ICIC)技术。 目前主要的eICIC技术包括：小区范围扩展、时域eICIC以及一些新技术辅助的eICIC。小区范围扩展是指通过设置一定的小区选择偏置值让更多用户接入到微小区,从而实现宏小区和微小区之间的负载均衡；时域eICIC是指让宏小区在物理层下行信道上空出一些几乎空白子帧(ABS)来为受干扰较为严重的微小区用户提供一些时域调度资源,从而减小下行干扰；其他一些eICIC技术主要以功率控制或载波聚合为基础来解决异构网络的小区间干扰问题。 本文提出了一种LTE-A异构网络时域eICIC优化方案。该方案基于LTE网络架构,在不影响原有的宏小区之间资源分配方案的前提下,针对引入Pico小区之后的异构场景,有效地解决了重叠小区之间的下行干扰问题。该方案采用了小区范围扩展技术和时域eICIC技术,通过将两种技术相结合,建立合理的数学模型,求解出最佳的小区范围扩展偏置值和宏小区ABS配置比例。与静态时域eICIC技术相比,该方案很大程度上提升了受干扰用户的接收SINR和Pico小区的吞吐率。 另一方面,就Femto小区而言,由于其采用了封闭用户组(CSG)的接入限制,没有接入权限的用户在非常靠近Femto小区时会受到其强烈的下行干扰。为了解决宏小区、Pico和Femto小区共存场景下的小区间干扰问题,本文分析了时域eICIC用于Femto小区存在的场景时所面临的问题,并在Macro小区和Pico小区同频异构组网场景下时域eICIC方案的基础上针对这些问题进行了进一步的方案优化。经系统级仿真验证,优化方案在保证不同小区之间用户公平性的条件下可以较大程度地提升宏小区和Pico小区的吞吐率
[Abstract]:At present, the new mobile communication system in the process of broadband, the number of supported data rate is increasing, and the types of services that can be provided continue to expand. In the case of traffic surge, the distribution of services in the cell will be more uneven, in some places where the user distribution is more concentrated, data service hot spots will be formed. On the one hand, the traditional network topology may lead to a serious decline in the received SINR of users in the hot area on the edge of the cell; on the other hand, it is not conducive to improving the spectral efficiency of the system. In order to solve this problem, 3GPP introduces the concept of heterogeneous network in LTE-A standard. In LTE-A heterogeneous networks, low power nodes, such as Pico and Femto, will be used to cover the same frequency in small range in order to improve the QoS of users in these areas. But at the same time, the same frequency network will introduce severe inter-cell interference between microcell and macro cell. The complex topology and interference scene of heterogeneous networks make the traditional ICIC (Inter-Cell interference Coordination) technology difficult to apply. Therefore, the enhanced ICIC (eICIC, enhanced ICIC) technology must be proposed. At present, the main technologies of eICIC include: cell range expansion, time domain eICIC and some new technology assisted eICs. The extension of cell scope refers to the load balancing between macro cell and micro cell by setting certain cell selection bias value to enable more users to access to microcell. Time domain eICIC is to let macro cell produce some almost blank sub-frames (ABS) over the downlink channel of physical layer to provide some time domain scheduling resources for the users with serious interference, so as to reduce the downlink interference. Some other eICIC technologies are mainly based on power control or carrier convergence to solve the problem of inter-cell interference in heterogeneous networks. This paper presents a time domain eICIC optimization scheme for LTE-A heterogeneous networks. This scheme is based on the LTE network architecture, and without affecting the original resource allocation scheme between macro cells, the downlink interference between overlapped cells is effectively solved for the heterogeneous scene after the introduction of Pico cells. By combining the two techniques, a reasonable mathematical model is established to solve the optimal cell range expansion bias value and the ratio of macro cell ABS configuration. The proposed scheme adopts the cell scope expansion technology and the time domain eICIC technology. Compared with the static time domain eICIC technology, the proposed scheme greatly improves the receiver throughput of SINR and Pico cells. On the other hand, as far as the Femto cell is concerned, because of the access restriction of the closed subscriber group (CSG), the users without access rights will be subjected to strong downlink interference when they are very close to the Femto cell. In order to solve the problem of intercellular interference in the coexistence of Pico and Femto cells, this paper analyzes the problems of time domain eICIC used in the scene of Femto cell. On the basis of the time domain eICIC scheme of Macro cell and Pico cell in the same frequency heterogeneous network scenario, the scheme optimization is carried out to solve these problems. System level simulation shows that the optimized scheme can greatly improve the throughput of macro and Pico cells under the condition of ensuring the fairness of users between different cells.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.5
本文编号：2130681
[Abstract]:At present, the new mobile communication system in the process of broadband, the number of supported data rate is increasing, and the types of services that can be provided continue to expand. In the case of traffic surge, the distribution of services in the cell will be more uneven, in some places where the user distribution is more concentrated, data service hot spots will be formed. On the one hand, the traditional network topology may lead to a serious decline in the received SINR of users in the hot area on the edge of the cell; on the other hand, it is not conducive to improving the spectral efficiency of the system. In order to solve this problem, 3GPP introduces the concept of heterogeneous network in LTE-A standard. In LTE-A heterogeneous networks, low power nodes, such as Pico and Femto, will be used to cover the same frequency in small range in order to improve the QoS of users in these areas. But at the same time, the same frequency network will introduce severe inter-cell interference between microcell and macro cell. The complex topology and interference scene of heterogeneous networks make the traditional ICIC (Inter-Cell interference Coordination) technology difficult to apply. Therefore, the enhanced ICIC (eICIC, enhanced ICIC) technology must be proposed. At present, the main technologies of eICIC include: cell range expansion, time domain eICIC and some new technology assisted eICs. The extension of cell scope refers to the load balancing between macro cell and micro cell by setting certain cell selection bias value to enable more users to access to microcell. Time domain eICIC is to let macro cell produce some almost blank sub-frames (ABS) over the downlink channel of physical layer to provide some time domain scheduling resources for the users with serious interference, so as to reduce the downlink interference. Some other eICIC technologies are mainly based on power control or carrier convergence to solve the problem of inter-cell interference in heterogeneous networks. This paper presents a time domain eICIC optimization scheme for LTE-A heterogeneous networks. This scheme is based on the LTE network architecture, and without affecting the original resource allocation scheme between macro cells, the downlink interference between overlapped cells is effectively solved for the heterogeneous scene after the introduction of Pico cells. By combining the two techniques, a reasonable mathematical model is established to solve the optimal cell range expansion bias value and the ratio of macro cell ABS configuration. The proposed scheme adopts the cell scope expansion technology and the time domain eICIC technology. Compared with the static time domain eICIC technology, the proposed scheme greatly improves the receiver throughput of SINR and Pico cells. On the other hand, as far as the Femto cell is concerned, because of the access restriction of the closed subscriber group (CSG), the users without access rights will be subjected to strong downlink interference when they are very close to the Femto cell. In order to solve the problem of intercellular interference in the coexistence of Pico and Femto cells, this paper analyzes the problems of time domain eICIC used in the scene of Femto cell. On the basis of the time domain eICIC scheme of Macro cell and Pico cell in the same frequency heterogeneous network scenario, the scheme optimization is carried out to solve these problems. System level simulation shows that the optimized scheme can greatly improve the throughput of macro and Pico cells under the condition of ensuring the fairness of users between different cells.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.5
【共引文献】
相关博士学位论文 前1条
1 张海君;IMT-Advanced异构无线网络中资源管理策略研究[D];北京邮电大学;2013年
相关硕士学位论文 前1条
1 杜亮;Nanocell系统接入控制和资源管理若干技术的研究[D];厦门大学;2014年
，本文编号：2130681
本文链接：https://www.wllwen.com/kejilunwen/wltx/2130681.html
