LTE-A技术中基于功能博弈的无线资源分配策略

针对LTE-A(长期演进技术的后续演进)技术的RRM(无线资源管理)及优化问题,提出一种在LTE-A系统中基于RRM功能博弈的无线资源分配策略。其主要思想是根据RRM中的两个功能——无线接纳控制和无线承载控制之间的竞合关系,建立博弈模型,通过求取博弈模型的纳什均衡,实现系统服务量的最大化,以达到运营商经济利益和用户满意度的有效统一。     

3G演进型技术标准化进程

宽带无线接入技术对蜂窝移动通信技术形成了挑战，加快了对更高传输速率的第三代移动通信演进型技术的研究和标准化进程。国际标准组织3GPP和B3GPP2均启动了对3G新轮演进型技术的研究和标准化工作。目前3GPP长期演进（LTE）项目在无线接口的关键技术指标、无线网络架构及高层协议方面取得了进展，3GPP2无线接口演进（AIE）项目在空中接口层二（L2）及更高层标准的制订、空中接口物理层标准的制订方面取得了进展。     

TD-LTE-A系统关键技术分析

LTE-A是3GPP为了满足ITUIMT-A(4G)的需求而推出的LTE后续演进技术标准,LTE-A系统中TDD模式———TD-LTE-A系统被认为是未来4G标准方案之一。为了满足IMT-Advanced系统中较高带宽的需求,3GPP在LTE-A标准中引入了载波聚合、自组网、分层网干扰协调增强和多点协作传输(CoMP)等关键技术。     

第三代移动通信系统WCDMA无线定位技术及其应用

无线定位技术是第三代移动通信系统中一个非常有前号的技术本文首先对无线定位技术的网络构架进行了描述,然后阐述了各个关键的网络元素的功能,然后分析研究了目前在3GPP标准中的几种定位方法以及各个定位方法的信令流程,最后对3G中无线定位技术的应用前景进行了展望。     

基于协作中继的LTE-A干扰对齐技术研究

为满足下一代移动通信系统高速率传输的要求,LTE-A系统引入了无线中继技术,用户终端可通过中继节点接入网络以获得高质量的服务。但是随着中继节点及用户的增加会导致系统的同道干扰更加突出,成为限制LTE-A网络容量的主要因素。因此,需要研究有效的干扰抑制技术以增强网络性能。近年提出的干扰对齐技术能够获得干扰网络的最大自由度并可达其最优容量。研究了基于低秩干扰空间的多小区干扰对齐技术,然后将该算法推广到LTE-A中继网络,提出了基于协作中继的LTE-A干扰对齐方案。仿真结果表明,提出的干扰对齐技术能够有效提高LTE-A中继网络容量。     

LTE/LTE-A技术及标准进展

随着无线数据业务的迅速增长,新空口技术的不断引入,无线扁平化技术的出现与兴起,无线网络架构会发生什么样的变化成为业界关注的焦点。本文对LTE/LTE-A的需求、研究进展、关键技术进行了介绍,浅析了EUTRAN的演进方式。     

LDPC编码在LTE-A中的应用研究

为了达到4G的指标要求,需要在LTE的基础上采用先进的技术,其中重要技术之一就是信道编码技术,因此演进了LTE-A技术。目前研究的信道编码技术有两种:改进的Turbo码和LDPC码。以LDPC码为例,对LTE-A展开研究,研究表明,LDPC编码性能在某些方面优于Turbo码,是LTE-A信道编码技术的较好选择。     

WCDMA无线定位技术及其应用

无线定位技术是第三代移动通信系统中一个非常有前景的技术。文章首先对无线定位技术的网络构架进行了描述,并阐述了各个关键的网络元素的功能,然后分析研究了目前在3G P P标准中的几种定位方法以及各个定位方法的信令流程,最后对3G中无线定位技术的应用前景进行了展望。     

LTE-A物理层下行参考信号的研究

LTE-A（改进的长期演进）OFDM系统接收端采用相干解调技术恢复原始数据信息,相干解调必须利用信道的相关信息,获取信道相关信息接收端需采用先进的信道估计技术实现。LTE-A OFDM系统是基于导频信号的信道估计获取信道的脉冲响应特性。本文主要对LTE-A物理层下行CRS（小区特定参考信号）进行了深入的分析研究。     

移动无线通信的过去和未来发展趋势

本文首先简要介绍了移动通信系统的发展历程,然后对3GPP系统、3GPP2系统和WiFi等宽带技术的标准,特点,系统参数、网络结构、应用范围和演进方向等进行了详细地比较和分析,重点讨论了3GPP系统无线接入网络演进过程中各种技术的标准、优缺点,改进措施及进一步演进,最后展望了未来移动无线通信的研究热点和发展趋势.     

LTE-A下行单用户MIMO增强技术研究

无线通信系统中,基站可以针对信道空间特性采用不同的下行传输模式获得空间复用增益和波束成形增益以提升系统性能。LTE-A中的下行单用户MIMO增强技术,采用了基于码本以及非码本的预编码技术优化性能,有必要分析其技术特点和增益来源以指导产品设计。分析了LTE-A中单用户MIMO技术演进的新特点,着重研究了新的双码本结构,在对信道属性匹配、码本搜索运算复杂度和UE上报载荷方面的改进。针对LTE-A预编码技术性能问题,通过计算机链路级仿真比较了LTE—A中基于码本以及非码本预编码技术的吞吐量性能,仿真结果表明码本技术较非码本技术具有一定优势。     

Smart heterogeneous networks: a 5G paradigm

An exponential growth in data demand on wireless networks and wireless link capacity approaching its theoretical limits, bound us to find new solutions and innovative network designs to handle the enormous amount of traffic. In this paper, we discuss long term evolution-advance (LTE-A) heterogeneous networks (HetNets) being a most effective solution to break this wireless cellular capacity crunch. LTE-A HetNets provide adequate increase in capacity by utilizing multi-tier architecture consisting of different type of cells i.e macro cell, small cell, relay and device to device. However this increase in capacity comes with certain challenges in HetNets outlined in this article. Considering inter cell interference coordination (ICIC) as biggest challenge in LTE-A HetNets, this article surveys state of the art LTE-A HetNets deployments with focus on ICIC. Effective ICIC techniques allow further substantial capacity increase. We give state of the art ICIC on air-interface as well as backhaul strategies for effective ICIC in LTE-A HetNets. Operators perspective of LTE-A HetNets with some insight to future of 5G LTE-A HetNets is provided. We also provide simulation results to show how LTE-A HetNets lead to realize ambitious targets of 5G technology in terms of capacity.     

Impact of antenna and beam-selection-based sectored relay planning for performance evaluation of 4G LTE-A tri-sectored cell

The deployment of Relay Nodes (RNs) in 4G LTE-A networks, mainly originating from the wireless backhaul link, provides an excellent network planning tool to enhance system performance. Better coordination between the base station and relays to mitigate inter-cell interference becomes an important aspect of achieving the required system performance, not only in the single-cell scenario, but also in multi-cell scenarios. In this paper, we model and analyze two basic approaches for designing a 4G LTE-A tri-sectored cellular system. The approaches are based on Antenna Selection Sectored Relaying (ASSR) and Beam Selection Sectored Relaying (BSSR). The main purpose of the proposed schemes is to enhance system performance by improving the quality of the wireless relay backhaul link. In this technique, antenna selection takes into consideration Non-Line-Of-Sight (NLOS) communication, whereas BSSR considers the case of Line-Of-Sight (LOS) communication using heuristic beam forming approach. The resource allocation problem has also been investigated for relay based cooperative LTE-A tri-sectored cell in the downlink. The best possible location for relay node in the sector, power allocation and MIMO channel modeling is formulated as an optimization problem with the aim of maximizing the end to end link rate and the Signal to Interference plus Noise Ratio (SINR) of 4G LTE-A systems. Power allocation/optimization has been solved by means of the duality equation of the stationary Karush-Kuhn-Tucker (KKT) condition and is used to derive optimal values for the beam forming vector on both the relay as well as the access link. The performance of the proposed scheme is verified through simulations carried out using MATLAB software. The simulation results show a significant improvement in the SINR, throughput capacity, and coverage area of the 4G LTE-A cell, while guaranteeing better quality of service.     

A Survey on Dynamic Spectrum Access for LTE-Advanced

Increasing utilization of LTE-Advanced (LTE-A) to meet the rapid growth in wireless bandwidth demand is an important focus for current research. Dynamic spectrum access (DSA) is a promising approach that can be utilized to improve bandwidth utilization in LTE-A systems and networks. The application of DSA is not limited to commercial use but can also be applied to provide access to other systems including public safety communication systems and device to device communications. This paper provides a general overview of DSA and a review of the recent research into the use of DSA to improve bandwidth utilization in LTE-A networks. DSA is a flexible technique that is being applied to different network technologies including cognitive radio, mobile cellular femtocells and wireless relay.

     

Radio resource management with QoS guarantees for LTE-A systems: a review focused on employing the multi-objective optimization techniques

The increasing number of subscribers’ demand has led to the evolution of future wireless networks that support multimedia applications and require ensuring the quality of services it provides. As the radio resource is becoming scarce, it is turning out to be a vital issue that how should the demands for higher data rates with limited resources is met for the evolving long term evolution-advanced (LTE-A) systems. Moreover, the efficiency and performance of resource management can be further improved by autonomously assigning and managing resources among various users and applications. We have surveyed various radio resource management (RRM) techniques being used for resource sharing in LTE-A networks that focus on the potential of multi-objective optimization algorithms for achieving desired QoS in LTE-A system. In this paper, we present a comprehensive review of RRM techniques, scheduling, and QoS along with a focus on implementing the multi-objective optimization techniques for efficient resource allocation.     

基于LTE-A系统下行双码字解调的算法设计

为了进一步提升下行通信的传输能力,提高有限资源的利用率,LTE-A系统在发送端给出采用专用导频端口的8层数据的映射方案。在LTE-A系统使用双码字和8层映射的基础上,设计了一种利用专用导频信息对双码字数据的解调算法,并通过仿真画出了LTE-A利用此算法解调数据的误码率。仿真结果表明,在无线环境较优时,利用此算法能够很好地控制误比特率(约为0.1),并证实了利用该算法解调数据的可靠性和实用性。     

LTE-A与WiMax2网间切换的研究与实现

随着通信技术的迅速发展,在无线通信领域,无论是GSM,TD-SCDMA,WCDMA,CDMA2000,WLAN,LTE,还是LTEA、WiMax2等都有各自独立的优缺点,任何一种无线通信技术都不能独立支持所有业务的发展,多种技术的共存与融合将会成为未来移动通信网络发展的趋势。基于LTE-A(TDD)和WiMax2网络融合的可行性研究成果,提出了一种异构网络下基于相对信号强度,滞后差值和触发时长作为判断准则的垂直切换算法。最后,采用MATLAB仿真工具,建立LTE-A(TDD)与WiMax2混合组网的仿真模型,来验证该算法的可行性。     

TCP traffic performance improving in LTE-A networks

This paper presents a novel way to improve Transmission Control Protocol (TCP) performance of the users at the edge areas of the macro cells in Long Term Evolution Advanced (LTE-A) systems. Previous works on improving wireless TCP performance are reviewed and current considerations on TCP in LTE-A are explained. However, those solutions are neither too complex nor limited to some presuppositions which are too restricting for the deployment of LTE-A networks. In this paper a substituted TCP acknowledgement transmission scheme based on Automatic Repeat reQuest (ARQ) information in layer 2 is proposed. The simulation result shows that the proposed method can reduce the delay and improve the throughput of the edging users of the cell, as well as reducing radio resources in LTE-A macro cells.     

Performance Enhancement of 5G OFDM Systems Using Modified Raised Cosine Power Pulse

Wireless Personal Communications - OFDM is a key modulation technology of current wireless communication systems such as 4G LTE/LTE-A. The fifth generation (5G) of wireless cellular networks is...