LTE-A异构网络中基于ABS配置和载波聚合的干扰协调方案研究
发布时间：2019-01-19 11:04
【摘要】：近年来,随着移动智能终端的普及和各种实时多媒体业务的广泛应用,宽带无线网络中的通信量以指数速率增长,随之产生的是对更高覆盖质量、更高数据速率业务需求的增长。相对于用户需求的快速增长来说,最严峻的问题就是频谱资源的稀缺。为了提高频谱利用率,LTE-Advanced (LTE-A)相比LTE进一步缩小了蜂窝尺寸,然而由于地形、建筑布局和其他条件的限制,蜂窝尺寸不可能无限缩小。尤其是对室内、热点区域、覆盖盲区等特殊场景,只是简单的缩小蜂窝尺寸并不能有效地解决问题。于是3GPP在LTE-A标准的制定过程中提出了异构网络(heterogeneous networks)技术用于解决上述问题,从而提升系统整体性能。 异构网络是一种全新的组网模式,由宏基站(Macro/MeNB)和其覆盖范围内部署的微微基站(Pico/PeNB)、家庭基站(Femto)和中继(Relay)等低功率节点混合组成。异构网络的部署拉近了终端用户和基站节点间的距离,有效提高了单位区域内的频谱利用率,并能改善热点区域、信号盲区和小区边缘的通信质量。异构网络作为一种极好的增强系统性能的方法,同时面临着很多技术上挑战,其中由于网络拓扑结构的改变以及异构网络同频部署带来的小区间干扰问题尤为重要。 在Macro-Pico异构小区场景下,由于Macro小区和Pico小区发射功率的差异,如果采用传统的小区接入准则会导致Pico小区服务的用户数非常有限,从而达不到部署Pico小区希望带来的系统性能增益。因此,异构网络中引入了小区范围扩展(Cell Range Expansion, CRE)技术来平衡Macro小区和Pico小区之间的负载。但是采用CRE技术以后,位于Pico小区边缘的用户,尤其是CRE区域内的用户会受到Macro小区强烈的下行干扰。因此本文提出将几乎空白子帧(Almost Blank Frame, ABS)比例和CRE偏置值进行联合优化的增强型小区间干扰协调(enhanced Iner-Cell Interference Coordination, eICIC)方案,该方案根据小区间的负载情况调整CRE偏置,然后基于稳定后的偏置调整ABS,找到使得系统吞吐量最大的ABS比例。 载波聚合是在LTE-A中提出的新技术,通过聚合多个成员载波(Component carrier,CC)达到扩展系统带宽的目的。LTE-A系统采用载波聚合技术后同时支持跨载波调度,既提高了调度的灵活性,又可以用于解决异构网络中的小区间干扰问题。本文提出一种基于载波聚合的干扰协调方案,让Macro小区在部分载波的控制信道(CCH)上静默,并保证在不损害系统整体性能的前提下,在这些载波的数据信道(DCH)上降低发射功率,以减轻对其覆盖范围内Pico小区边缘用户的干扰。
[Abstract]:In recent years, with the popularity of mobile intelligent terminals and the wide application of various real-time multimedia services, the traffic in broadband wireless networks has increased exponentially, resulting in higher coverage quality. Higher data rate business demand growth. Relative to the rapid growth of user demand, the most serious problem is the scarcity of spectrum resources. In order to improve spectral efficiency, LTE-Advanced (LTE-A) further reduces the size of honeycomb compared with LTE. However, due to the constraints of terrain, architectural layout and other conditions, the size of honeycomb can not be reduced indefinitely. Especially for indoor, hot spot, blind area and other special scenes, simply reducing the size of honeycomb can not effectively solve the problem. So 3GPP put forward the heterogeneous network (heterogeneous networks) technology to solve the above problems in the process of establishing the LTE-A standard, so as to improve the overall performance of the system. Heterogeneous network is a new networking mode, which is composed of Acer Base Station (Macro/MeNB) and pico base station (Pico/PeNB) deployed within its coverage, home base station (Femto) and relaying (Relay), etc. The deployment of heterogeneous network can shorten the distance between the end user and the base station node, effectively improve the spectral efficiency of unit area, and improve the communication quality of hot spot, signal blind area and cell edge. As an excellent method to enhance system performance, heterogeneous networks are facing many technical challenges. Among them, the problem of inter-cell interference caused by the change of network topology and the co-frequency deployment of heterogeneous networks is particularly important. In the Macro-Pico heterogeneous cell scenario, because of the difference of the transmission power between the Macro cell and the Pico cell, if the traditional cell access criterion is adopted, the number of users serving the Pico cell will be very limited. Thus, the system performance gains that the deployment of Pico cells want to bring can not be achieved. Therefore, cell range extension (Cell Range Expansion, CRE) is introduced into heterogeneous networks to balance the load between Macro cells and Pico cells. However, after the adoption of CRE technology, users located on the edge of Pico cell, especially those in CRE area, will be strongly interfered by the downlink of Macro cell. Therefore, this paper proposes an enhanced inter-cell interference coordination (enhanced Iner-Cell Interference Coordination, eICIC) scheme, which optimizes the (Almost Blank Frame, ABS) ratio of almost blank subframes and the CRE offset value, which adjusts the CRE bias according to the load of the cell. Then, based on the stable bias adjustment ABS, we find the ABS proportion that makes the system throughput maximum. Carrier aggregation is a new technique proposed in LTE-A to expand the system bandwidth by aggregating multiple member carriers (Component carrier,CC). The LTE-A system uses carrier aggregation technology to support cross-carrier scheduling at the same time. It not only improves the flexibility of scheduling, but also can be used to solve the inter-cell interference problem in heterogeneous networks. In this paper, a interference coordination scheme based on carrier aggregation is proposed, in which the Macro cell is silent on the partial carrier control channel (CCH), and the overall performance of the system is not compromised. Transmission power is reduced on the data channel (DCH) of these carriers to mitigate interference to Pico cell edge users within their coverage.
【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：2411310
[Abstract]:In recent years, with the popularity of mobile intelligent terminals and the wide application of various real-time multimedia services, the traffic in broadband wireless networks has increased exponentially, resulting in higher coverage quality. Higher data rate business demand growth. Relative to the rapid growth of user demand, the most serious problem is the scarcity of spectrum resources. In order to improve spectral efficiency, LTE-Advanced (LTE-A) further reduces the size of honeycomb compared with LTE. However, due to the constraints of terrain, architectural layout and other conditions, the size of honeycomb can not be reduced indefinitely. Especially for indoor, hot spot, blind area and other special scenes, simply reducing the size of honeycomb can not effectively solve the problem. So 3GPP put forward the heterogeneous network (heterogeneous networks) technology to solve the above problems in the process of establishing the LTE-A standard, so as to improve the overall performance of the system. Heterogeneous network is a new networking mode, which is composed of Acer Base Station (Macro/MeNB) and pico base station (Pico/PeNB) deployed within its coverage, home base station (Femto) and relaying (Relay), etc. The deployment of heterogeneous network can shorten the distance between the end user and the base station node, effectively improve the spectral efficiency of unit area, and improve the communication quality of hot spot, signal blind area and cell edge. As an excellent method to enhance system performance, heterogeneous networks are facing many technical challenges. Among them, the problem of inter-cell interference caused by the change of network topology and the co-frequency deployment of heterogeneous networks is particularly important. In the Macro-Pico heterogeneous cell scenario, because of the difference of the transmission power between the Macro cell and the Pico cell, if the traditional cell access criterion is adopted, the number of users serving the Pico cell will be very limited. Thus, the system performance gains that the deployment of Pico cells want to bring can not be achieved. Therefore, cell range extension (Cell Range Expansion, CRE) is introduced into heterogeneous networks to balance the load between Macro cells and Pico cells. However, after the adoption of CRE technology, users located on the edge of Pico cell, especially those in CRE area, will be strongly interfered by the downlink of Macro cell. Therefore, this paper proposes an enhanced inter-cell interference coordination (enhanced Iner-Cell Interference Coordination, eICIC) scheme, which optimizes the (Almost Blank Frame, ABS) ratio of almost blank subframes and the CRE offset value, which adjusts the CRE bias according to the load of the cell. Then, based on the stable bias adjustment ABS, we find the ABS proportion that makes the system throughput maximum. Carrier aggregation is a new technique proposed in LTE-A to expand the system bandwidth by aggregating multiple member carriers (Component carrier,CC). The LTE-A system uses carrier aggregation technology to support cross-carrier scheduling at the same time. It not only improves the flexibility of scheduling, but also can be used to solve the inter-cell interference problem in heterogeneous networks. In this paper, a interference coordination scheme based on carrier aggregation is proposed, in which the Macro cell is silent on the partial carrier control channel (CCH), and the overall performance of the system is not compromised. Transmission power is reduced on the data channel (DCH) of these carriers to mitigate interference to Pico cell edge users within their coverage.
【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
【参考文献】
相关期刊论文 前1条
1 李俊;陈力;王彬;张欣;杨大成;;LTE-Advanced系统部署Pico后的小区间干扰协调技术[J];现代电信科技;2011年Z1期
，本文编号：2411310
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