SIA OpenIR  > 工业控制网络与系统研究室
面向工业无线网络的实时介质访问的控制方法研究
Alternative TitleReal-time Media Access Control for Industrial Wireless Networks
林俊如1,2
Department工业控制网络与系统研究室
Thesis Advisor于海斌 ; 梁炜
ClassificationTN92
Keyword工业无线网络 实时性 Mac协议 介质访问控制
Call NumberTN92/L61/2013
Pages117页
Degree Discipline机械电子工程
Degree Name博士
2013-11-28
Degree Grantor中国科学院沈阳自动化研究所
Place of Conferral沈阳
Abstract无线技术以易安装、易维护、低成本以及部署灵活等优势,成为了工业应用中极具前景的通信解决方案。然而,由于工业应用对通信的实时性、确定性、可靠性、网络规模等方面的苛刻要求,以及无线信道的共享特性和高误码率,无线技术要在工业,特别是工厂自动化中应用依然面临诸多挑战。要实现高实时、高可靠通信,且具备较大的网络规模,介质访问控制方法(Media Access Control,MAC)显得十分重要。一方面,介质访问控制在保证通信确定性方面的作用不可替代。另一方面,介质访问控制涉及通信资源的调度与分配问题,是实时、可靠通信的关键部分。因此,论文针对工业应用的需求和特点,展开了无线网络实时介质访问控制的研究工作。针对无线传感器网络在输电线路在线监测应用中拓扑结构、网络流量等方面的特点,提出了一种链式无线传感器网络的接入和传输方法,在保证实时性的同时,兼顾了网络的能耗。首先,基于拓扑特征提出了基于紧密集的分簇算法和基于命名机制的路由算法,解决了簇内能耗不均衡的问题。随后,为适应不同时期网络流量差异大的特点,提出了一种混合的介质访问协议。在空闲时期,设计了S-XMAC协议,并提出了基于位置信息的唤醒时间调度方法,满足了网络对告警等上行数据的实时性要求;在繁忙时期,提出了流水线式的传输调度方法,以避免隐藏终端问题,从而支持大数据量信息的实时传输。针对工厂自动化应用信息报文短、传输频发所导致的无线技术传输效率低下的问题,利用OFDM无线技术,提出了一种基于频域轮询的新型介质访问控制机制。该机制通过利用OFDM子载波进行轮询,可实现大量节点的并行轮询,大大降低了轮询的协议开销;通过基于能量的轮询响应检测降低了方法的复杂性,提高了方法的可实现性。在轮询基础上,使用动态TDMA调度,提高了TDMA的带宽利用率;同时,提出了下行ACK响应聚合方法,缩短了时隙长度并提高了物理层传输报文的效率。现有的针对实时业务的OFDMA资源分配算法,均以整体速率最大化或总能量最小化为优化目标。但由于在针对的业务模式和追求的性能目标方面的差异,这些算法不适合工厂自动化应用的要求。针对这一问题,提出了以最小化超时概率为优化目标的TD-OFDMA系统上行通信资源分配的优化模型。随后,结合最大化通信可靠性的速率和功率分配规则,提出了一种面向工厂自动化的TD-OFDMA上行链路的启发式资源分配算法。和IEEE 802.16中针对实时业务的上行链路资源调度算法相比,本文所提算法在支持的节点数量、对信道质量的适应性及超时丢包率的性能上有显著的提高。对工厂自动化无线网络进行实验验证,存在着难于进行物理层技术验证、MAC层实验缺少硬件平台支持及难于实现大规模环境下的性能验证的问题。为了解决这些问题,开发了一套半物理仿真平台。首先,基于GNU Radio和USRP N210,为频域轮询等物理层相关技术提供了实验和验证手段;另外,在商用的IEEE 802.11硬件上,实现了确定性传输及高精度同步等功能,为具有确定性要求的介质访问控制实现提供了基础服务;最后,利用OPNET仿真软件建立协议模型,用于分析协议/算法在较大规模网络情况下的性能。该半物理仿真平台提供小规模实验验证和大规模仿真验证的方式,能够验证协议/算法的有效性,并对协议/算法的设计与开发提供指导。
Other AbstractWireless technology is considered as a promising solution for industrial communications due to its advantages in easier and costless installation and maintenance. However, stringent communication requirements of industrial application, in terms of real time, predictability, reliability and network capacity, and limitations of wireless environments such as more error prone, low per-station throughput, make it really challenging when wireless technology is utilized in industrial applications, especially in factory automation applications. In order to accomplish industrial wireless networks with high reliability, real time and high network capacity, media access control strategy is especially import, because it plays an indispensable role in guaranteeing communication’s predictability. It also a critical part to accomplish real-time and reliable communication as it involves allocation of communication resources. So this dissertation does research on real-time media access control of wireless network according to industrial applications’ requirements and characteristics. Content details of this dissertation are summarized as follows:Based on the characteristics of network topology and traffic patterns, unique communication requirements of transmission line monitoring, an efficient wireless sensor network framework, which guarantees real time performance and achieves energy efficient transmission at the same time, is proposed. This framework includes a clustering algorithm and an address-based routing protocol to resolve the problem of intra-cluster energy unbalance. A hybrid MAC (H-MAC) is proposed to handle traffic variability. In H-MAC, we use S-XMAC, which takes advantage of loose synchronization, to reduce the number of preambles sent before data packet transmission, and we also propose a location-based wake up schedule to optimize the real time performance of uplink data. In the busy period, we use Pipelined MAC to deal with the hidden terminal problem and support the sensors with large volume of data.To alleviate the inefficiency of wireless transmission caused by highly frequent communication with small packets in industrial applications, a new media access scheme based on frequency domain polling (FDP-MAC) is proposed. In this scheme, by using physical layer signaling techniques of OFDM systems for polling, FDP-MAC is capable of polling many stations concurrently, thus significant overheads are reduced. Besides, based on polling results, a dynamic TDMA scheduling scheme is presented to improve the bandwidth utilization, a downlink ACK aggregation scheme is also introduced to alleviate the inefficiency of static TDMA scheduling and wireless physical layer in industrial scenarios.Most of current OFDMA resource allocation algorithms for real time services are based on sum rate maximization or total power consumption minimization, however, these algorithms are not applicable to communication systems in industrial applications. Thus an optimization problem, whose object is timeout probability minimization, for uplink resource allocation in TD-OFDMA system is proposed. A heuristic algorithm for this problem is also introduced, compared with other algorithms for real time services, this algorithm outperforms other algorithms in terms of performances which are more concerned in industrial communication.Most researches on wireless technologies for industrial applications are limited to simulations and experimental studies are rare. To bridge this gap, a verification platform includes experimental testbed and simulation platform is developed. The high data rate wireless networks experimental testbed is based on TDMA mechanism and commodity IEEE 802.11 hardware, the testbed can be utilized for developments and experiments of filed level industrial wireless network protocols. It can also undertake experimental studies on wireless technologies in physical layer or closed to physical layer, by using GNU Radio and software radio USRP N210. In order to evaluate protocols/algorithms’ performance in large-scale network, simulation software OPNET is utilized, meanwhile the experimental data from experimental testbed is inputted to OPNET to promote the credibility of results.
Language中文
Contribution Rank1
Document Type学位论文
Identifierhttp://ir.sia.cn/handle/173321/14825
Collection工业控制网络与系统研究室
Affiliation1.中国科学院沈阳自动化研究所
2.中国科学院大学
Recommended Citation
GB/T 7714
林俊如. 面向工业无线网络的实时介质访问的控制方法研究[D]. 沈阳. 中国科学院沈阳自动化研究所,2013.
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