【作者】 袁勇；

【导师】 杨宗凯；

【作者基本信息】 华中科技大学 ， 信息与通信工程， 2005， 博士

【摘要】 随着芯片技术、通信技术和传感技术的飞速发展,目前传感技术正迈入无线传感器网络新时代。这种网络由大量集成有传感器、数据处理单元和无线通信模块的微小节点组成,通过自组织方式构成网络,借助于节点中内置形式多样的传感器,可以将所在周边环境信号,通过网络方式及时有效地传输到信息接收端,极大提高了传感器监测面积和性能,提高了监测网络可靠性和生存性,可以被广泛地应用于国防军事、国家安全、环境监测、交通管理、医疗卫生、制造业、反恐抗灾等领域。然而,由于节点靠电池供给能量,而又不易对如此众多的节点更换电池,节省能耗延长网络生命期就成为了无线传感器网络的关键; 另一方面,由于无线传感器网络应用领域非常广泛,不同应用领域对网络有不同程度的服务质量要求,如端到端传输实时性、可靠性。因此,设计能耗低同时又能灵活有效支持服务质量的无线传感器网络技术,对于无线传感器网络实用化具有非常重要的意义。根据对节点部件的分析,发现其能耗主要来源于传感、无线传输以及数据处理三个操作,而无线传输能耗远远超过其他两项操作需要重点考虑。另一方面,无线传感器网络各项技术,如网络路由技术,分布式信息处理技术都需要无线传输,因此,无线传输技术被公认为其余各项技术的基础,其性能好坏直接影响到其余技术设计,也根本性地影响到整网能耗与服务质量支持,因此,本文以无线传感器网络中的无线传输技术作为切入点,对能耗与服务质量支持进行了深入系统的研究。根据多跳传输、节点能力受限但数量大以及多应用共存的特点,无线传感器网络中的无线传输技术主要涉及到下面几方面的内容:点到点与端到端层面的传输技术; 通过多点协作的传输技术以及多应用环境下的传输技术。因此,本文根据无线传感器网络的特点,重点研究了这几个方面的无线传输技术,关注于其中的节能与服务质量支持问题及两者的联合优化。这些工作得到了国家自然科学基金“基于媒体传输特性的无线多媒体技术的研究”(No.60202005)的资助。本文取得的研究成果包括如下几个方面: (1) 点到点自适应码位调制无线通信技术本文分析了无线传感器网络对无线通信的低功耗,低复杂度,共存性及自适应更多还原

【Abstract】 With the rapid development of chip, communication and sensing technologies, wireless sensor network (WSN) has become the key technology in the new era of sensing technologies. In WSN, the tiny nodes, which consist of sensing, data processing and wireless communication components, are deployed densely and randomly in large numbers. The tiny nodes form the WSN in a self-organization manner. Based on the diverse onboard sensors, the WSN can sense the field and communicate the information to the remote sink in an efficient and timely manner. The sensing performance and reliability have been improved significantly in WSN. So the WSN can be widely used in military sensing, security, environmental monitoring, traffic surveillance, medical treatment, building and structures monitoring, even anti-terrorism, etc. However, since the sensor nodes are battery driven and it is impractical to recharge the battery for so many nodes after deployment, energy efficiency has been a key concern in the research work of WSN. On the other hand, in many WSN applications, the data gathering has the Quality of Services (QoS) requirements in terms of BER performance, end-to-end timeliness and reliability, etc. Therefore, to design the protocols with low energy consumption and flexible QoS provisioning is the guarantee for the efficient information gathering in WSN. According to the analysis of sensor nodes, the main sources of energy consumption are sensing, wireless transmission and data processing. And the energy consumption caused by wireless transmission is much more than sensing and data processing. On the other hand, since most technologies in WSN, such as data routing, distributed information processing, have the requirements for the wireless transmission. Wireless transmission technologies have been identified as the key technologies determining the energy consumption and QoS, which are also the basis for other technologies. Therefore, in this thesis, the author carried out a deep and systematic research work on the energy efficiency and QoS provisioning in WSN by designing the wireless transmission technologies. According to the characteristics of multi-hop transmission, limited energy resource, high density of sensor nodes and the coexistence of multiple applications’requests, the main aspects of wireless transmission technologies in WSN include point-to-point and end-to-end wireless transmission, cooperative wireless transmission among multiple nodes and the wireless transmission in multiple applications scenarios. Therefore, a systematic research work is done in this thesis to design these wireless transmission technologies with focus on energy saving and QoS provisioning. The work has been supported by the National Science Foundation of China "Investigation of Wireless Multimedia Techniques based on Multimedia Transmission Property" (No.60202005). The contributions of this thesis include: (1) Point-to-point wireless communication technology based on adaptive code position modulation This thesis analyzes the requirements of low power consumption and complexity, coexistence and self-adaptation on the design of the point-to-point wireless communication scheme in WSN. The disadvantages of the traditional short-range wireless communication technologies are analyzed. Then, a novel adaptive code position modulation technology is proposed for WSN. The technology has the merit of low power consumption and low complexity. And the communication parameters of the technology can be adjusted adaptively according to the channel condition and QoS requirements, so as to minimize energy consumption and provide QoS gaurantee. (2) End-to-end energy and QoS aware wireless transmission technology This thesis jointly integrates the application’s QoS requirements, network routing protocol and the transmission technology into a single framework. The impact of the communication parameters in the framework on the overall energy consumption and QoS performance are investigated and modelled. Based on the results, a centralized offline control policy is designed in the integrated framework to adjust the communication parameters for fixed QoS provisioning. And a distributed online control policy is also designed based on the feedback control theory for dynamic QoS provisioning. (3) Multi-hop cooperative MIMO wireless transmission technologyThis thesis analyzes the phenomena of radio irregularity and multipath fading in some applications of WSN. And a cooperative MIMO technology is designed by forming multiple single antenna nodes as the virtual antenna array. Based on the technology, a cluster based multihop cooperative MIMO protocol is designed, in which the cooperative MIMO technology is incorporated into the transmission between cluster heads. The energy consumption model of the protocol is developed and an adaptive cooperative nodes selection strategy is also designed in the protocol. (4) Energy aware transmission technology in supporting multiple applications’ requests This thesis analyzes the coexistence of multiple data gathering applications in WSN. An energy aware wireless transmission technology is developed with focus on the coexistence of multiple applications. The technology has two main components, the optimal transmission policy for each application and the optimal admission control policy for multiple applications. The objective is to maximize the expected overall reward under the residual energy constraint of the network. In designing the optimal transmission policy, a convex optimization model is developed in terms of the transmission scheme and the overall energy consumption of the network. Then the mature optimization technique is employed to solve the model and find the optimal transmission policy. In the design of the optimal admission control policy, the problem is abstracted as a dynamic and stochastic knapsack problem. The related theory is employed to model the problem. Based on the model, the related algorithms are used to design a distributed optimal admission control policy for multiple applications. In this thesis, a systematic research work on the wireless transmission technologies in most possible scenarios has been done with focus on energy efficiency and QoS provisioning. The achievements of the research work can be used to guide the design of the wireless transmission technologies in the real WSN products. And it can also be used in the applications with QoS requirements, such as fire detection and object tracking.更多还原