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1、中国科学技术大学 硕士学位论文 无线传感器网络中基于分簇的虚拟MIMO传输策略的研究 姓名：肖明 申请学位级别：硕士 专业：计算机软件与理论 指导教师：黄刘生 2011-04-19 摘 要 I 摘摘 要要 无线传感器网络被认为是引领未来经济和社会发展的革命性技术，它将计 算、网络和物理环境有机的融合，能够实现物理世界与信息世界的实时感知、信 息交互和动态控制。无线传感器网络的应用领域涵盖了军事、航空航天、能源、 生物、日常生活的各个方面，目前已经成为国内外学术界研究的重要方向、企业 界优先发展的产业领域。不同于传统的无线自组织网络，无线传感器网络有着非 常严格的能量限制， 因此如何降低能耗以延
2、长网络的生存时间一直是研究人员和 用户都最为关心的问题。 通信能耗是无线传感器网络能耗的主要来源，而多输入多输出（Multi-input Multi-output，MIMO）技术是一个有效提高无线通信能量效率的方案。MIMO技 术通过在发射端和接收端上安装多根天线来获取分集增益， 在相同的发射功率和 误码率要求下能够显著节省通信能耗。但是普通的传感器节点受到体积、功耗以 及制造成本等因素的限制，无法直接安装多天线来实现MIMO通信。而虚拟 MIMO技术利用多个单天线节点以协作的方式构成虚拟多天线节点，克服了节点 受体积限制无法安装多天线的问题，从而将MIMO通信的分集增益引入无线传感 器网络中
3、以节省数据传输能耗。因此虚拟MIMO技术被众多研究人员视为延长无 线传感器网络生存时间的一个全新的解决方案，然而要将虚拟MIMO技术应用于 无线传感器网络中仍有许多问题亟待解决或完善，如何设计能量有效的虚拟 MIMO传输策略便是其中之一。 本文以最大化无线传感器网络的生存时间为目标，围绕如何设计能量有效的 虚拟 MIMO 传输策略展开分析和研究，并根据传输方式的不同，分别提出了两 种新颖的基于分簇的虚拟 MIMO 传输策略。本文的主要工作和贡献如下： 1） 基于分簇的虚拟 MIMO 传输策略被证明可以显著提高网络传输能量效率， 然而现有的工作只考虑了如何利用协作通信减少簇间传输能耗， 在簇内传
4、输时仍 采用传统的单输入单输出（Single-input Single-output，SISO）通信方式，需要消 耗较多的能量。本文将结合协作数据聚集和分簇协议，提出了一个基于簇内协作 对的虚拟 MIMO 单跳传输策略（ICPVM） ，该策略通过选择簇内协作对（CPN） 进行数据聚集，从而节省簇内传输能耗。我们将 CPN 选择问题形式化为一般图 的最大加权匹配，并采用 PGA（Path Growing Algorithm）算法求解该问题。仿 真结果表明，与现有的虚拟 MIMO 单跳传输策略相比，ICPVM 传输策略能够有 效延长网络生存时间达 27%以上。 2）多跳通信是无线传感器网络的重要特
5、征之一，结合虚拟 MIMO 技术和多 跳路由可以进一步节省数据传输能耗。目前所提出的虚拟 MIMO 多跳传输策略 摘 要 II 的单跳通信过程至少包括 2 个步骤：簇内数据广播和簇间协作转发。本文提出了 一个基于虚拟 MIMO 多播的多跳传输策略（VMMM） ，由于该策略避免了多跳 数据转发时的簇内广播过程，从而极大地提高了整个网络的能量有效性。为优化 该传输策略的性能，本文对 VMMM 策略的能耗进行了建模分析，并在此基础上 通过联合优化以确定满足最小能耗时的网络参数。仿真结果表明，与之前提出的 虚拟 MIMO 多跳传输策略相比， VMMM 传输策略能够有效延长网络生存时间达 50%以上。
6、关键词：关键词：无线传感器网络；虚拟MIMO；基于分簇；能量有效；网络生存时间； Abstract III ABSTRACT Wireless sensor networks (WSN) is considered as a revolutionary technology leading the development of future economic and society. Through the integration of cyber and physical worlds, WSN enables people to sense, communicate and interac
7、t with the physical world in all aspects of daily life, military, aerospace, energy, biology, etc, and thus has gained more and more attention from academy and industry. However, WSN has constrained energy constraint, which is different from traditional wireless self-organization network. Therefore,
8、 how to prolong the network lifetime by decreasing energy consumption is one of the most key problems in the research field of WSN. Wireless transceivers usually consume a major portion of batter energy in WSN, and MIMO (Multi-input Multi-output) technique is shown to be a perfect solution to enhanc
9、e wireless communication energy efficiency. Through using multiple-antennas in transmitting and receiving end, the MIMO technique could achieve diversity gain, which could significantly reduce energy consumption under the same transmit power budget and bit error rate. However, due to the constraints
10、 of size, power and cost, it is impossible to equip each sensor with multiple antennas to realize MIMO communications for WSN. In order to tackle this problem, researchers propose the virtual MIMO technique to allow multiple single-antenna nodes cooperate with each other, forming a virtual multi-ant
11、ennas node. Using virtual MIMO technique in WSN could make use of the diversity gain to decrease the transmission energy consumption. Therefore, the virtual MIMO technique is regarded as a promising solution to prolong the lifetime of WSN. However, the application of virtual MIMO technique to WSN st
12、ill faces many problems, in which how to design an energy efficient virtual MIMO transmission scheme is one of the key problems. Taking network-lifetime maximization as our primary purpose, we investigate the problem on how to design an energy efficient virtual MIMO transmission scheme, and propose
13、two novel cluster-based virtual MIMO transmission schemes. The major contents and contributions of this paper are as follows: 1) Cluster-based virtual MIMO transmission scheme is shown to significantly enhance transmission energy efficiency. However, existing works only consider how to reduce the en
14、ergy consumption of inter-cluster transmission by cooperative Abstract IV communication, and intra-cluster transmission still use traditional SISO (Single-input Single-output) communication, which consume more energy. In this paper, we propose a new cluster-based virtual MIMO transmission scheme (IC
15、PVM) by combining cooperative data aggregation with cluster protocol. Through selecting intra-cluster cooperative pairs (CPN) for data aggregation, the proposed scheme can obtain energy savings of intra-cluster transmission. We formalize the CPN selection problem to the maximum weighted matching (MW
16、M) in general graphs, and adopt PGA (Path Grow Algorithm) to solve it. Simulation results show that compared with the previous virtual MIMO transmission scheme, our scheme prolongs the network lifetime by at least 27%. 2) Multi-hop communication is an important feature of WSN, and data transmission energy consumption could be reduced further by incorporating multihop routing and virtual MIMO technique. So far, the existing vi
