LTE自组织网络技术及其应用

异构网(Het Net)的引入及多制式网络的共存,使4G LTE网络运维复杂程度大为增加。2007年3GPP在进行LTE标准制订时,引入了LTE自组织网络(SON)机制,旨在移动网络建设和优化时能自动完成网络设备的参数配置,提升网络建设与维护效率,降低网络运营成本。经过多年的演进发展,SON功能已日渐丰富和完善。介绍了SON技术及其体系架构,举例说明了SON技术在我国的应用情况及效果,提出了SON技术发展面临的挑战。     

LTE-Advanced SON自优化和自愈用例研究

为了最大限度降低网络运行费用,提供自组织网络(SON)是LTE-Advanced的主要目标之一。文章介绍了自组织网络的产生背景,给出了移动负载均衡(MLB)解决方案,分析了移动鲁棒性优化(MRO)的工作原理,描述了随机接入信道优化过程,提出了节能思路,最后研究了自组织网络功能管理参考模型。     

浅析TD-LTE自优化功能实现方法

自优化功能是LTE系统中自组网技术的关键功能之一,多个无线网络参数将直接影响优化结果。文章对LTE中可调优化参数的相关性进行深入分析,以定量和定性两个方面准确地衡量各个参数之间的关系以及其自身重要程度,并提出自组网优化架构及相关流程,为工程实施提供指引。     

LTE中自组织网络技术的标准化进展

随着LTE标准的演进,自组织网络（SON）技术也不断发展。由运营商发起的自组织网络不同于传统的无线网络规划、优化方式。SON技术可以减少运营成本,提高操作效率及网络性能和稳定性。介绍了SON的标准化发展情况,重点分析了SON中的几个关键技术。随着SON标准和技术的不断完善,可以预见自组织网络将大大降低未来无线网络的运营成本。     

GSM网络无线利用率提升思路研究

随着LTE网络发展,VoLTE话务持续迁转, GSM语音话务量和语音业务占比持续走低;同时,运营商在GSM 900M频段上陆续完成FDD和NB-IoT网络部署,900M频段出现GSM、FDD LTE、NB-IoT共存的局面,频率资源进一步紧张。本文研究了GSM网络无线利用率提升思路,通过实现GSM网络资源利用率有效提升,为现网载频压降及频率压缩提供空间,为后续网络平稳演进做好准备。     

Minimal Delay Traffic Grooming in WDM Optical Star Networks

All-optical networks face the challenge of reducing slower opto-electronic conversions by managing assignment of traffic streams to wavelengths in an intelligent manner, while maximizing the bandwidth resources utilization. This challenge becomes harder in networks closer to the end users that have insufficient data to saturate single wavelengths as well as traffic streams outnumbering the usable wavelengths. Traffic grooming has been proposed as a possible solution in the network closer to the end users. However, it requires costly traffic analysis at access nodes. We study the problem of traffic grooming that reduces the need to analyze traffic, for a class of network architecture mostly used by Metropolitan Area Networks; the star network. We first prove that the problem is NP-hard, then provide an efficient greedy heuristics that can be used to intelligently groom traffics at the LANs to reduce latency at the access nodes. Simulation results show that our greedy heuristics achieves a near-optimal solution.     

LTE自组织网络MRO功能浅析

随着LTE网络规模的不断扩大,网络中存在的异常切换次数也逐渐增多。本文主要针对SON中的MRO功能及其实现方法进行了详尽的论述,并通过现网验证,优化后网络KPI指标有所提升,异常切换比例下降。     

Coverage and capacity optimization in LTE network based on non-cooperative games

As to provide the optimal coverage and capacity performance,support high-data-rate service and decrease the capital expenditures and operational expenditures(OPEX)(CAPEX) for operator,the coverage and capacity optimization(CCO) is one of the key use cases in long term evolution(LTE) self-organization network(SON).In LTE system,some factors(e.g.load,traffic type,user distribution,uplink power setting,inter-cell interference,etc.) limit the coverage and capacity performance.From the view of single cell,it always pursuits maximize performance of coverage and capacity by optimizing the uplink power setting and intra-cell resource allocation,but it may result in decreasing the performance of its neighbor cells.Therefore,the benefit of every cell conflicts each other.In order to tradeoff the benefit of every cell and maximize the performance of the whole network,this paper proposes a multi-cell uplink power allocation scheme based on non-cooperative games.The scheme aims to make the performance of coverage and capacity balanced by the negotiation of the uplink power parameters among multi-cells.So the performance of every cell can reach the Nash equilibrium,making it feasible to reduce the inter-cell interference by setting an appropriate uplink power parameter.Finally,the simulation result shows the proposed algorithm can effectively enhance the performance of coverage and capacity in LTE network.     

上海贝尔端到端LTE解决方案

介绍了上海贝尔的LTE端到端解决方案,该方案包含eUTARN、ePC、移动网络演进传送构架（META）和业务分发环境（SDE）;阐述了上海贝尔采用统一通用平台、融合演进的eNodeB对2G/3G网络的向下兼容;提供了完美的QoS保障和业务流量管理的分组演进核心,并为适应无线网络演进提出了全新的传送网络构架来支持2G/3G和LTE网络传输和未来演进。     

LTE网管系统建设研究

介绍了LTE网管系统管理功能要求,特别是网络自配置?自优化?自愈等LTE SON 技术,对网管设置原则及现网主流厂家网管设备的架构和配置进行了综合评述? 同时根据工程实际及运营需求对LTE网管组网方案进行探讨,并提出地址分配及网络路由方案?最后通过系统架构的对比,分析4G无线综合网管系统与3G综合网管系统二者之间的差异?     

LTE规模部署中潜在的网络安全风险分析

近年来,LTE成为全球通信行业的发展热点。针对LTE/SAE的安全特性,对LTE规模部署过程中面临的如控制平面拥塞、异常流量攻击、网络融合等各层面的安全风险进行深入分析,并提出相应的安全防护建议。这些安全防护建议包括安全域划分、信令保护、异常流量防护等措施,以期对我国LTE规模部署的安全保障提供必要的参考。     

混合业务场景下的合作博弈动态资源管理策略

LTE系统对各类多媒体业务的承载能力对其未来应用至关重要。面向混合业务场景，本文建立了合作博弈模型描述各类业务之间的关系，并提出了一种动态资源管理策略。系统根据当前业务状态为各类业务分配所需资源，进而，根据业务属性确定各个用户的调度优先级。结果表明所提出的资源管理策略能够有效提高系统频谱效率及各类业务的服务质量。     

Towards successful VoLTE and VoWiFi deployment: network function virtualization solutions’ benefits and challenges

The Recent decades have witnessed intensive efforts from operators to implement methods enabling better control over network utilization, service usage, and service monetization. Nevertheless, they report significant growth in Diameter signaling traffic, especially policy management signaling traffic. More specifically, operators offering long term evolution (LTE) data-only services and planning for a massive introduction of voice over LTE (VoLTE) and voice over WiFi (VoWiFi) services need to tackle the enormous growth in Diameter signaling traffic. The biggest challenge for those operators is to find an appropriate solution, scalable enough to handle the unpredictable growth of Diameter signaling traffic; as the VoLTE and VoWiFi services will reshape the landscape of LTE policies. Throughout this paper, we propose a network function virtualization (NFV) based model, mature enough to tackle the challenges of those operators planning to launch VoLTE and VoWiFi, without impacting existing services and without jeopardizing current revenues. In our approach we first used standard VoLTE and VoWiFi message flow and referenced users’ behavior; then we considered NFV architecture characteristics. We finally referred to the latest experiments and test results related to NFV maturity cycle.     

Small‐cell planning in LTE HetNet to improve energy efficiency

Cell planning is one essential operation in wireless networks, and it significantly affects system performance and cost. Many research efforts consider the cell planning problem with identical base stations (BSs) or to construct a new network on the region without any infrastructure. However, long‐term evolution (LTE) adopts heterogeneous network, which allows operators to tactically deploy small cells to enhance signal coverage and improve performance. It thus motivates us to propose a small‐cell planning problem by adaptively adding low‐powered BSs with the limitation of budget to an existing network to increase its energy efficiency, which is defined by the ratio of network throughput to the amount of energy consumption of BSs. We consider 2 types of LTE small cells, namely, microcells and picocells, and develop different clustering strategies to deploy these cells. Based on the available resource and traffic demand in each cell, we then adjust the transmitted power of the deployed BS with energy concern. Experimental results demonstrate that our small‐cell planning solution can achieve high‐energy efficiency of LTE networks, which means that BSs can better use their transmitted energy to satisfy the traffic demands of user devices. This paper contributes in proposing a practical problem for cell planning with heterogeneous network consideration and developing an efficient solution to provide green communications.     

Network Dimensioning in WDM-Based All-Optical Networks

The problem of network dimensioning, which involves optimal network designs using minimal resources for a given well-predicted traffic between individual nodes but without a pre-determined network topology, is analyzed in details in this paper. Such optimal designs are critical as the network resources are directly related to the cost of implementation. The problem complexity increases as the traffic between every node pair varies in a periodic manner. Furthermore, the presence of wavelength conflicts makes the network-dimensioning problem distinct and more complicated than that for traditional circuit-switching networks. Here, we adopt the approach based on a multi-commodity flow problem. A general cost function covering the resources of all system components is formulated, and two solution approaches are presented; one based on integer programming and one on heuristics.     

FDD LTE与TD-LTE业务速率分析

LTE网络现已规模化建设,其业务速率是指导网络规划的基础。通过分析LTE物理资源块以及信令格式,并对FDD LTE与TD-LTE的常规CP和扩展CP去除开销的上行各种Preamble格式峰值业务速率和下行的峰值业务速率进行仿真以及分析,得到了两种制式不同CP方式的速率差异。     

Adaptive envelope process and minimum service curve applied to resource block allocation in the LTE downlink

In this work, we propose a resource allocation algorithm for the LTE downlink that makes use of an adaptive multifractal envelope process and a minimum service curve. The proposed scheduling algorithm aims to improve some network parameters while guaranteeing a maximum delay to the user by considering the following information: backlog, channel condition and user traffic behavior. In order to estimate the maximum network delay, we propose an adaptive minimum service curve for the LTE network that can be used for admission control purposes in the resource allocation algorithm. The performance of the proposed scheduling algorithm is compared to those of several scheduling schemes known in the literature through computational simulations of the LTE downlink. In order to develop a new adaptive envelope process and to precisely describe network flows, we propose an adaptive algorithm to estimate the parameters of the Multifractal Wavelet Model (MWM). The proposed envelope process is compared to the main traffic model based envelope processes known in the literature. Simulations of the LTE downlink considering AMC (Adaptive Modulation and Coding) are carried out showing the efficiency of the proposed resource allocation approach that considers adaptive estimation of network traffic parameters.     

Dimensioning of the LTE access network

This paper proposes efficient analytical models to dimension the necessary transport bandwidths for the Long Term Evolution (LTE) access network satisfying the QoS targets required by different services. In this paper, we consider two major traffic types: elastic traffic and real time traffic. For each type of traffic, individual dimensioning models are proposed for both the S1 interface and the X2 interface. For elastic traffic the dimensioning models are based on the Processor Sharing models; while for real time traffic the dimensioning models are based on the fundamental queuing models. For validating these analytical dimensioning models, a developed LTE system simulation model is used. Extensive simulations are performed for various traffic and network scenarios. The analytical results derived from the proposed dimensioning models are compared with the simulation results. The presented results demonstrate that the proposed analytical models can appropriately estimate the required performances for different service classes and priorities. Hence they are suitable to be used for dimensioning of the LTE access network with different traffic and network conditions.     

LTE网络中业务识别方案的研究与实现*1

为了实现对长期演进(Long Term Evolution,LTE)网络的业务识别,分析了S1接口用户面协议栈,利用模块化设计思想实现了对S1接口流量的业务识别.针对传统业务识别系统识别度低、统计能力不强的缺陷,在传统的业务识别系统基础上,提出了一个多识别的业务识别方案,实现了对业务类型的精确识别.经过现网数据测试验证,所设计的多识别的业务识别方案达到了预期的效果,在LTE移动通信网络业务识别领域具有推广意义.     

Service overlay networks: SLAs, QoS, and bandwidth provisioning

We advocate the notion of service overlay network (SON) as an effective means to address some of the issues, in particular, end-to-end quality of service (QoS), plaguing the current Internet, and to facilitate the creation and deployment of value-added Internet services such as VoIP, Video-on-Demand, and other emerging QoS-sensitive services. The SON purchases bandwidth with certain QoS guarantees from the individual network domains via bilateral service level agreement (SLA) to build a logical end-to-end service delivery infrastructure on top of the existing data transport networks. Via a service contract, users directly pay the SON for using the value-added services provided by the SON. In this paper, we study the bandwidth provisioning problem for a SON which buys bandwidth from the underlying network domains to provide end-to-end value-added QoS sensitive services such as VoIP and Video-on-Demand. A key problem in the SON deployment is the problem of bandwidth provisioning, which is critical to cost recovery in deploying and operating the value-added services over the SON. The paper is devoted to the study of this problem. We formulate the bandwidth provisioning problem mathematically, taking various factors such as SLA, service QoS, traffic demand distributions, and bandwidth costs. Analytical models and approximate solutions are developed for both static and dynamic bandwidth provisioning. Numerical studies are also performed to illustrate the properties of the proposed solutions and demonstrate the effect of traffic demand distributions and bandwidth costs on SON bandwidth provisioning.