【作者】 徐雷；

【导师】 徐大专；

【作者基本信息】 南京航空航天大学 ， 通信与信息系统， 2012， 博士

【摘要】 随着无线通信网络的迅速发展和多媒体业务需求的日益增长，有限的频谱资源和业务服务质量(Quality of Service, QoS)要求不断增长之间的矛盾日益尖锐。为了缓解这一矛盾，无线网络资源分配技术成为当前无线通信领域研究的热点，并且正交频分复用(Orthogonal FrequencyDivision Multiplexing, OFDM)技术的独特优势为资源分配提供了灵活的自由度。因此，OFDM无线网络中的资源分配问题在近几年得到了广泛的关注。本文研究了OFDM无线网络中的资源分配算法，重点研究了蜂窝网络、无线局域网和无线Mesh网络的资源分配问题。本文在前人工作的基础上，对前人工作进行了改进，主要工作如下：针对上行多用户多输入多输出正交频分复用(Multi-Input Multi-Output Orthogonal FrequencyDivision Multiplexing, MIMO-OFDM)蜂窝网络的资源分配问题，在考虑各用户最小传输速率需求和TCM编码的情况下，以最小化蜂窝网络平均消耗总功率为目标提出了一个基于有限反馈的资源分配算法。该算法首先根据拉格朗日乘子法和凸优化理论中Karush-Kuhn-Tucher条件设计发射速率码本、发射功率码本和等效信道量化门限码本，然后基站根据各用户当前的信道状态信息分配子载波并对等效信道增益量化，最后基站广播资源分配结果。该算法不仅有效降低蜂窝网络平均消耗总功率，而且具有有限反馈的特点。针对上行多用户MIMO-OFDM蜂窝网络的资源分配问题，在考虑尽力而为业务和TCM编码的情况下，以最大化网络吞吐量为目标提出了一个基于有限反馈的资源分配算法。该算法首先根据发射模式码本和用户的误比特率需求定义各用户当前时刻的有效发射模式集合，其次根据拉格朗日对偶法和凸优化理论中的Karush-Kuhn-Tucher条件推导了各用户链路质量指示函数；最后，根据次梯度迭代的方法更新拉格朗日乘子。该算法在不仅能提高蜂窝网络的吞吐量，而且具有有限反馈的特点。针对单用户MIMO-OFDM蜂窝网络的资源分配问题，在考虑延时信道状态信息和信道编码情况下，以最大化吞吐量为目标提出了一个低复杂度的资源分配算法。该算法首先利用延时信道状态信息推导了考虑编码增益的保证用户误比特率需求的星座距离表达式；然后证明了该优化问题是凸优化问题，并根据拉格朗日乘子法和凸优化理论中Karush-Kuhn-Tucher条件推导了最优比特和功率加载的封闭形式解；最后通过加载的比特取整和功率调整得到最终的资源分配解。该算法不仅能有效逼近单用户整数比特加载时的最优吞吐量，而且具有计算复杂度低的特点。针对下行多用户MIMO-OFDM蜂窝网络的比例公平资源分配问题，在考虑延时信道状态信息和用户比例速率权重的情况下，以最大化应用时间窗内的网络吞吐量为目标提出了一个基于应用时间窗的比例公平算法。该算法首先把基站总功率在各子载波上等功率分配，并且把网络中的每个用户按照其比例速率权重映射为相应数目的虚拟用户；然后根据运筹学中影子价格(Shadow Price)的概念定义虚拟用户在子载波上接入时间分配准则；最后根据子载波接入时间分配准则和分类的影子价格得到最终的子载波接入时间百分比。该算法不仅能保证用户的公平性，而且能有效提高网络吞吐量。针对上行多用户MIMO-OFDM无线局域网的跨层资源分配问题，在考虑多包接收和用户数据包长度的情况下，以最小化传输时间为目标提出了低复杂度的基于多包接收跨层资源分配算法和改进的基于多包接收跨层资源分配算法。首先，研究了在物理层采用基于波束形成的MIMO-OFDM传输技术和在媒体接入控制(Media Access Control, MAC)层采用基于多包接收的分布式协调功能(Distributed Coordination Function, DCF)协议；然后，根据Huang文献的无线局域网基于多包接收的数学优化模型提出了一个低复杂度的跨层资源分配算法，该算法在网络性能和计算复杂度之间取得良好的折中；最后，针对Huang文献的数学优化模型不足进行了修改，即把网络的总功率限制用各个用户的最大功率限制替代，并在此基础上提出了一个改进的基于多包接收跨层资源分配算法，该算法不仅能有效提高网络吞吐量，而且能降低平均包延时。针对基于OFDM技术的多跳无线Mesh网络资源分配问题，在各链路最大发射功率限制和满足各链路实时业务传输速率需求的情况下，以最大化网络效用函数为目标提出了一个联合考虑功率、时隙和子载波的资源分配算法。该算法首先根据语音业务和视频业务的特点为各链路的实时业务分配时隙-子载波对，并且为各链路语音业务和视频业务设计服务区分机制；然后把一帧中剩余的时隙-子载波对分配给边际效应最大的链路来增加网络的数据业务吞吐量；最后根据注水原理进行功率分配。该算法不仅能保证网络语音业务和视频业务的QoS要求，而且能有效提高数据业务吞吐量。更多还原

【Abstract】 The rapid development of the wireless networks and the explosive growth of multimediaapplications inevitably aggravate the contradiction between the limited spectrum resource and theincreasing quality of service (QoS) requirement of multimedia services. To alleviate the contradiction,the wireless network resource allocation technology becomes the hot research field recently. Due tothe distinct advantages of orthogonal frequency division multiplexing (OFDM), it provides flexiblefreedoms for resource allocation. Thus, resource allocation in OFDM system has attracted greatinterests in recent years. In this thesis, the resource allocation algorithms in OFDM wireless networksincluding cellular network, wireless local area network and wireless Mesh network are intensivelystudied. In this thesis, we make some improvements on the basis of previous work. The main work ofthis thesis are listed as follows:For the cellular network resource allocation problem of the uplink multiuser multi-inputmulti-output orthogonal frequency division multiplexing (MIMO-OFDM), a minimizing powerresource allocation algorithm based on limited feedback which considers the minimum transmissionrate requirement of each user and TCM is proposed. Firstly, the algorithm designs the codebook ofrate, power and equivalent channel quantization threshold utilizing the Lagrange multiplier methodand the Karush-Kuhn-Tucher condition of convex optimization theory. Secondly, the subcarriers areallocated according to current channel state information and the equivalent channel gain is quantized.Finally, the base station broadcasts the resource allocation solution to users. Proposed algorithm notonly saves efficiently the energy of cellular network, but also has advantage of limited feedback.For the cellular network resource allocation problem of the uplink multiuser MIMO-OFDM, amaximizing throughput resource allocation algorithm based on limited feedback which considers thebest effort service and TCM is proposed. Firstly, the algorithm defines the effective set oftransmission mode per user according to the code of transmission mode and the requirement of BER.Secondly, the function of link quality indicator is derived according to the Lagrange dual method andthe Karush-Kuhn-Tucher condition in convex optimization theory. Finally, updates the Lagrangemultipliers utilizing sub-gradient iterative method. Proposed algorithm not only improves the networkthroughput, but also has advantage of limited feedback.For the cellular network resource allocation problem of single user MIMO-OFDM, a maximizingthroughput resource allocation algorithm which considers the delay channel state information and channel coding is proposed. Firstly, the algorithm derives the constellation distance which guaranteesthe requirement of the user’s BER utilizing the delay channel state information from the perspectiveof coding gain. Secondly, it proves that the optimization problem is convex and the closed formsolution for optimal power and bit loading is derived according to the Lagrange multiplier method andthe Karush-Kuhn-Tucher condition of convex optimization theory. Finally, the resource allocationsolution is obtained through rounding bit and power adjustment. Proposed algorithm is close to theoptimal integer bit loading solution of single user and has advantage of low computationalcomplexity.For the cellular network resource allocation problem of the downlink multiuser MIMO-OFDM, aproportional fairness resource allocation algorithm which considers the delay channel stateinformation and users’ proportional rate weight is proposed. Firstly, the algorithm allocates the totalpower of base station equally across the subcarrier and maps each user into the corresponding virtualusers according to the users’ proportional rate weight. Secondly, it defines the subcarrier allocationcriteria of virtual users accessing time according to the concept of shadow price in operation research.Finally, it obtains the percentage of subcarrier accessing time in accordance with the subcarrierallocation criteria and shadow price classification. Proposed algorithm can improve the networkthroughput efficiently under the condition of guaranteeing the proportional fairness of users.For the wireless local area network resource allocation problem of the uplink multiuserMIMO-OFDM, cross-layer resource allocation algorithm with low complexity and improvedcross-layer resource allocation algorithm which consider multi-packet reception and the data packet’slength are proposed. Firstly, we study MIMO-OFDM transmission technology based on beamformingat the physical layer and the distributed coordination function (DCF) protocol based on multi-packetreception at the media access control (MAC) layer. Secondly, we propose a low complexity crosslayer resource allocation algorithm based on multi-packet reception according to the mathematicaloptimization model of Huang’s literature. This algorithm has a good compromise between networkperformance and computational complexity. Finally, in order to overcome the mathematicaloptimization model deficiency of Huang’s literature we substitute the total power of the network withthe maximum power of each user and propose an improved cross-layer resource allocation algorithmbased on multi-packet reception. This algorithm not only effectively improves the network throughput,but also reduces the average packet delay.For the resource allocation problem of the multi-hop wireless Mesh network based on OFDMtechnology, a joint power-timeslot-subcarrier resource allocation algorithm which considers the maximum transmission power constraint of each link and the real-time traffic transmission raterequirement of each link is proposed. Firstly, according to the characteristics of voice traffic and videotraffic the algorithm allocates the pair of timeslot-subcarrier for the real-time traffic of each link anddesigns the service differentiation mechanism for the voice traffic and video traffic of each link.Secondly, it allocates the remaining pairs of timeslot-subcarrier in the frame to the largest marginaleffect link in order to increase the network throughput of data traffic. Finally, water filling algorithmis performed in the power allocation stage. Proposed algorithm not only guarantees the QoSrequirement of voice traffic and video traffic, but also improves the throughput of data trafficeffectively.更多还原