3GPP LTE计划

为了把握新一轮的技术浪潮,保持在移动通信领域的领导地位,3GPP在2004年底启动了3G演进型系统,即LTE(长期演进)的研究与标准化工作,并计划在2007年发布第一个版本的系统规范。目前,该项目已完成了SI(研究阶段)的工作,各方面研究都取得了一定进展。文章简要介绍了LTE的背景情况、项目计划、主要性能目标、关键技术以及目前的研究进展和发展趋势。     

3GPP LTE标准化进展

为了保持在移动通信领域的技术及标准优势,3GPP启动其长期演进（LTE）的标准化工作。在物理层（层1）、空中接口协议结构层（层2）和网络结构方面,3GPPLTE采纳一系列先进技术和创新理念,IP语音（VoIP）业务和多媒体广播及多播业务（MBMS）的解决方案的优化正在进行中,目前已经实现高数据率、低时延和基于全分组的设计目标。     

3GPP组织LTE研究进展

高级国际移动电信(IMT-Advanced)是一种新概念,用于描述具有超过IMT-2000能力的新移动系统.3GPP不仅为实现IMT-Advanced而不懈工作,同时也在为实现LTE-Advanced而努力.LTE-Advanced预计会成为3GPP R10规范的一部分,IMT-Advanced可能在2013年或更晚一...     

Progress of 3GPP LTE Standardization

The 3rd Generation Partnership Project (3GPP) initiated its Long Term Evolution (LTE) standardization work to retain its technology and standard advantages in the field of mobile communications. A series of advanced technologies and novel concepts related to the physical layer (Layer 1),air interface protocol structure layer (Layer 2) and network architecture are adopted. Solutions to Voice over IP (VoIP) and Multimedia Broadcast/Multicast Service (MBMS) are in the optimization process. 3GPP LTE has achieved the design goals of high data rate,low latency and an all-packet basis.     

具有低复杂度和QoS敏感的LTE调度算法

基于线性松弛原理和贪心法,设计并实现了一种适用于LTE网络、具有全QoS保证能力的低复杂度QPF调度算法。该算法分为时域和频域2个部分,对GBR业务和Non-GBR业务可一次性实现全部资源的分配,将算法复杂度从O(MN)下降到O(M lb N)。仿真表明,该调度算法各项性能较为均衡,在高负荷时部分性能较参考算法有10%的提升,较好地解决了调度的性能和复杂度之间的矛盾。     

3GPP LTE系统中小区负载均衡机制的研究

第三代合作伙伴计划(3GPP)长期演进(LTE)系统与上一代无线通信网络相比,在基站传输速率和小区容量上都有了极大的提高,相应地对网络无线资源管理功能也提出了更高的要求.文章探讨了无线资源管理中的一个重要方面:负载均衡的问题.首先分析了网络中小区可能发生过载的原因,并讨论了传统的基于小区切换的解决方法可能存在的风险.随...     

Energy-saving scheduling for LTE multicast services

In the Long Term Evolution （LTE） downlink multicast scheduling, Base Station （BS） usually allocates transmit power equally among all Resource Blocks （RBs）, it may cause the waste of transmit power. To avoid it, this paper put forward a new algorithm for LTE multicast downlink scheduling called the Energy-saving based Inter-group Proportional Fair （EIPF）. The basic idea of EIPF is to calculate an appropriate transmitting power for each group according to its data rate respectively, and then follow the inter-group proportional fair principle to allocate RBs among multicast groups. The results of EIPF simulation show that the proposed algorithm not only can reduce the transmit power of BS effectively but also improve the utilization rate of energy.     

Coexistence studies for 3GPP LTE with other mobile systems - [LTE part II: 3GPP release 8]

To ensure LTE systems can coexist with other mobile systems operating in the same geographical area, or the LTE Base Station (BS) can be collocated with other mobile system BSs, coexistence studies for LTE with other systems have been carried out in 3GPP. In this article, we provide an overview of the coexistence studies that have been done. First we list the terminologies that are commonly used for coexistence studies, and explain how deterministic analysis can be done for the BS to BS interference scenario. Then we provide the system simulation methodology and assumptions used in the coexistence studies, and show some simulation results for the possible impacts with different system parameters. Finally we provide the references to the 3GPP standards where the LTE BS and UE radio transmission and reception requirements are specified to facilitate LTE coexistence with other mobile systems.     

3GPP LTE小区间干扰协调方案研究

随着3G移动通信系统逐步成熟,3GPP已经开始了对其长期演进(LTE)系统的研究和标准化工作。由于使用了新的物理层技术,使得小区间干扰抑制成为一个热点问题。针对该问题,介绍了目前小区间干扰协调/躲避研究方面的现状,对几种具有代表性的方案进行了研究,最后对各方案进行了系统级计算机仿真分析。     

认知无线电在3GPPLTE中的应用

介绍了认知无线电的概念与应用研究,在此基础上论述了将认知无线电技术应用于LTE（Long Term Evolution）系统中的必要性和可行性;讨论了认知无线电在LTE系统的无线资源管理和其自组织网络形成两个方面的应用,同时给出了相应的认知结构模型。     

一种3GPP LTE伪随机序列生成优化算法

伪随机序列(Pseudo-random Sequence)被广泛应用在通信系统中信道估计、信号加扰和频率跳转等方面.3GPP LTE标准采用Gold序列作为伪随机序列,针对Gold序列生成公式中存在较大状态偏移量以及常规算法生成序列耗时较多等问题,提出了利用状态转移矩阵快速生成序列的优化算法.实验表明,基于TI公司TMS3206455开发测试平台,在生成相同长度序列时,优化算法比常规算法能减少大约17 000多个系统时钟周期,至少节省49%系统资源,对提高系统整体性能有重要意义.     

面向通信系统的GPP平台内核调度算法研究

Linux内核调度算法直接影响基于通用处理器(GPP)平台的通信系统传输性能。文中分析了Linux内核基于截止时间算法(DEADLINE)和先进先出算法(FIFO)的原理,及DEADLINE算法的准入条件。在此基础上搭建了基于GPP的LTE系统实验平台,通过实验比较了基于两种内核调度算法的通信系统在时间响应、CPU使用率等方面的性能。结果表明,基于DEADLINE算法的通信系统时间响应性能优于FIFO,提高了28.38%,同时CPU使用率提高了36.53%。实验结果对基于不同场景搭建软件定义无线电平台提供了参考。     

3GPP LTE系统安全性研究

长期演进（LTE）系统代表TUMTS标准的最新发展方向,作为一种纯分组系统,它具有全新的无线接口和体系结构,其频谱效率是HSDPA／HSUPA的2倍。本文分析了LTE系统安全的主要内容,提出TLTE用户安全的体系结构,描述TIP网络的NDS体系结构,介绍了隧道模式下的ESP保护原理。     

3GPP LTE: The Future of Mobile Broadband

The mobile broadband technologies are reaching a commonality in the air interface and networking architecture; they are being converged to an IP-based network architecture with Orthogonal Frequency Division Multiple Access (OFDMA) based air interface technology. From technical perspective, fundamental goal of mobile broadband is to offer higher data rates with reduced latency. The third Generation Partnership Project (3GPP) presents the Long-Term Evolution (LTE) project in order to accommodate increasing mobile data usage and new multimedia applications. In the near future, with the recent progress made by technical specifications and vendor technology demonstrations LTE will emerge as successor to cellular systems as a broadband wireless solution. This paper provides an overview of 3GPP LTE including its history, features, technology, architecture and future. The technology components include OFDMA air-interface, Multiple-Input and Multiple-Output (MIMO) antenna technology and higher order modulation. The architecture includes Evolved Packet Core (EPC) and Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) components. This paper will concentrate to describe the main functions of the most important network elements. Also, the aim of this paper is to present the future potential of LTE which will make it an inevitable choice for wireless network operators around the globe.     

Adaptive call admission control in 3GPP LTE networks

In this article, we propose new methods to reduce the handoff blocking probability in the 3rd Generation Partnership Project Long Term Evolution wireless networks. This reduction is based on an adaptive call admission control scheme that provides QoS guarantees and gives the priority of handoff call over new call in admission. The performance results of the proposed schemes are compared with other competing methods using simulation analysis. Simulation results show the major impact on the performance of the 3rd Generation Partnership Project Long Term Evolution network, which is reflected in increased resource utilization ratio to (99%) and in the ability in satisfying the requirements of QoS in terms of call blocking probability (less than 0.0628 for Voice over IP service) and dropping probability rate (less than 0.0558).Copyright © 2012 John Wiley & Sons, Ltd.     

3GPP LTE的预编码和空间多路复用MIMO技术

当多路径信道在一个或多个MIMO接收机上无法提供足够的SINR时,3GPP LTE中的预编码技术可以极大地提高系统性能.测试结果表明,各种测量均可在多路径和信道失真条件下,对预编码系统的操作和性能进行非常有用的深入分析.     

3GPP LTE系统的切换机制研究

3GPP LTE是基于OFDM和MIMO技术对当前3G系统的中长期演进,对现有的3G系统的网络结构和无线接入方式都有较大的改进.文章详细分析了3GPP LTE所规范的切换过程,并对各大厂商提出的移动终端接入目标基站的几种方法(同步和非同步)做了比较性研究.     

3GPP LTE系统中无线视频传输调度算法研究

摘要：针对3GPP LTE系统,本文提出了适用于下行链路视频业务的一种新的分组调度算法,即时延优先比例公平调度（Delay First-Proportional Fair Scheduling,DF-PFS）。当需要做出调度决策时,该算法利用每个用户的数据包时延信息和瞬时下行信道条件,在满足用户QoS前提下最大限度地提高系统吞吐量。同时,当用户选择资源块（RB）进行传输后,即从用户集合中将该用户删除,避免接近eNodeB的用户一直占用无线资源,确保了资源分配的公平性。实验仿真结果表明,该算法在丢包率和PSNR性能上优于最大权重时延优先（M-LWDF）算法,在保证用户间公平性前提下,满足了视频业务的QoS要求。     

基于TD-LTE系统的无线资源调度策略分析与实现

MAC层调度是TD-LTE系统最核心的部分,其目的是充分利用无线信道的时变特性,得到多用户的分集增益.针对不同系统容量与吞吐量的设计目标原则,调度策略按照轮询、最大载干比、比例公平3种方法实现.通过系统实现与实测表明,最大载干比算法以牺牲系统容量为代价在系统吞吐量上有明显增益;比例公平算法则很好地兼顾了系统容量与吞吐量,相比于最大载干比算法在容量上有显著提升.     

支持实时多媒体业务QoS醮LTE下行调度研究

日益增长的多媒体业务要求下一代移动通信系统支持具有不同QoS要求的业务。针对LTE下行链路资源分配和调度问题,介绍了支持实时多媒体业务QoS调度算法的最新成果与进展,并对未来研究方向进行了分析展望。