Internet of things and wireless sensor networks

wireless sensor networks and the internet of things selected challenges and internet of things in healthcare applications
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Published Date:13-07-2017
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White Paper ® Internet of Things: Wireless Sensor Networks Executive summary Today, smart grid, smart homes, smart water Section 2 starts with the historical background of networks, intelligent transportation, are infrastruc- IoT and WSNs, then provides an example from the ture systems that connect our world more than we power industry which is now undergoing power ever thought possible. The common vision of such grid upgrading. WSN technologies are playing systems is usually associated with one single con- an important role in safety monitoring over power cept, the internet of things (IoT), where through the transmission and transformation equipment and use of sensors, the entire physical infrastructure is the deployment of billions of smart meters. closely coupled with information and communica- Section 3 assesses the technology and charac- tion technologies; where intelligent monitoring and teristics of WSNs and the worldwide application management can be achieved via the usage of net- needs for them, including data aggregation and worked embedded devices. In such a sophisticat- security. ed dynamic system, devices are interconnected to Section 4 addresses the challenges and future transmit useful measurement information and con- trends of WSNs in a wide range of applications trol instructions via distributed sensor networks. in various domains, including ultra large sensing A wireless sensor network (WSN) is a network device access, trust security and privacy, and formed by a large number of sensor nodes where service architectures to name a few. each node is equipped with a sensor to detect Section 5 provides information on applications. physical phenomena such as light, heat, pressure, The variety of possible applications of WSNs to the etc. WSNs are regarded as a revolutionary real world is practically unlimited. On one hand, information gathering method to build the WSNs enable new applications and thus new information and communication system which possible markets; on the other hand, the design will greatly improve the reliability and effi ciency is affected by several constraints that call for new of infrastructure systems. Compared with the paradigms. This section outlines WSN uses for the wired solution, WSNs feature easier deployment smart grid, smart water, intelligent transportation and better fl exibility of devices. With the rapid systems, and smart home domains. technological development of sensors, WSNs will become the key technology for IoT. Section 6 offers analysis of standardization being a major prerequisite in achieving the interoperability In this White Paper we discuss the use and of WSNs, not only between products of different evolution of WSNs within the wider context of vendors, but also between different solutions, IoT, and provide a review of WSN applications, applications and domains. while also focusing the attention on infrastructure technologies, applications and standards featured Section 7 concludes with a number of key in WSN designs. This White Paper is the sixth in recommendations for industry, regulators, the IEC, a series whose purpose is to ensure that the IEC and general observations on WSN security and can continue to contribute with its International data topics. Standards and Conformity Assessment services to solve global problems in electrotechnology. 3Executive summary Acknowledgments This White Paper has been prepared by the Wireless Sensor Networks project team, in the IEC Market Strategy Board. The project team includes: Dr. Shu Yinbiao, Project Leader, MSB Member, SGCC Dr. Kang Lee, Project Partner, NIST Mr. Peter Lanctot, IEC Dr. Fan Jianbin, SGCC Dr. Hu Hao, SGCC Dr. Bruce Chow, Corning Incorporated Mr. Jean-Pierre Desbenoit, Schneider Electric Mr. Guido Stephan, Siemens Mr. Li Hui, Siemens Mr. Xue Guodong, Haier Mr. Simon Chen, SAP Mr. Daniel Faulk, SAP Mr. Tomas Kaiser, SAP Mr. Hiroki Satoh, Hitachi Prof. Ouyang Jinsong, ITEI China Mr. Wang Linkun, ITEI China Ms. Wang Shou, ITEI China Dr. Zhen Yan, Nari Group Corporation Dr. Sun Junping, China-EPRI Prof. Yu Haibin, SIA Dr. Zeng Peng, SIA Dr. Li Dong, SIA Dr. Wang Qin, University of Science and Technology, Beijing 4Table of contents List of abbreviations 9 Glossary 12 Section 1 Introduction 13 1.1 Overview 13 1.2 Scope of this White Paper 14 Section 2 History and industrial drivers of WSNs 15 Section 3 WSN technology 19 3.1 Characteristic features of WSNs 19 3.2 Sensor nodes 20 3.2.1 Miniaturization technology of sensor based on MEMS 20 3.2.2 Ambient energy harvesting technology 21 3.3 Access network technologies 22 3.4 Topology 24 3.4.1 Self-organizing and reliable networking technology 25 3.4.2 Low cost IP interconnection technology 25 3.4.3 Self-adaptive fl ow control technology 27 3.5 Data aggregation 28 3.6 Security 29 3.6.1 Trust, security and privacy 29 3.6.2 Crypto algorithms 30 3.6.3 Key management of WSNs 31 3.6.4 Secure routing of WSNs 31 3.6.5 Secure data aggregation of WSNs 32 5Table of contents Section 4 Challenges of WSNs 33 4.1 System qualities, architecture divergence, and the need for an architecture framework 33 4.2 Ultra-large sensing device access 35 4.2.1 Massive heterogeneous data processing 35 4.2.2 Intelligent control and services to dynamic changes 35 4.3 Sensor network architecture 36 4.4 High concurrent access 36 4.4.1 High concurrent access with frequency division multiplexing 37 4.4.2 High concurrent access with distributed antenna systems 37 4.5 High real-time transmission 37 4.5.1 Distributed solution 38 4.5.2 Centralized solution 38 4.6 Semantic representation and processing 40 4.7 More secure WSNs 40 4.7.1 Protocol security framework 41 4.7.2 Trust, security and privacy 41 Section 5 WSN applications in the infrastructure systems 43 5.1 WSN application in the smart grid 43 5.1.1 Online monitoring system for transmission lines 43 5.1.2 Intelligent monitoring and early warning system for substations 44 5.1.3 Online monitoring and early warning system for distribution networks 46 5.1.4 Smart electricity consumption services 47 5.2 WSN application in smart water networks 48 5.2.1 Sustainability (water resource focus) 48 5.3 WSN application in intelligent transportation 50 5.3.1 Sensing of traffi c fl ows 50 5.3.2 City logistics 51 5.3.3 On-board WSNs 51 5.3.4 WSN in traffi c infrastructures 52 5.4 WSN application in smart homes 52 5.4.1 The energy challenge 52 5.4.2 Energy effi ciency in buildings – Case study 53 6Table of contents 5.4.3 Active control in buildings 54 5.4.4 WSNs are key for improving the energy effi cient performances of existing buildings 55 5.5 Additional application benefi ts of WSN 57 5.5.1 Improve energy effi ciency 57 5.5.2 Contribute to environmental monitoring 57 5.5.3 Enhance social services 57 Section 6 Standards of WSNs and systems 59 6.1 General 59 6.2 Present status 59 6.3 Standardization needs and outlook 67 6.4 Challenges and future standardization needs 68 Section 7 Conclusions and recommendations 69 7.1 General recommendations 69 7.2 Recommendations addressed to the IEC and its committees 70 Annex A Access technologies 71 A.1 Developing trend of access technologies 71 A.1.1 Bluetooth 4.0 71 A.1.2 IEEE 802.15.4e 72 A.1.3 WLAN IEEE 802.11™ 73 References 75 7List of abbreviations ABS anti-lock braking system Technical and scientifi c terms AMI advanced metering infrastructure CAPEX capital expenditure CoAP constrained application protocol COSEM companion specifi cation for energy metering CPU control processing unit DLMS device language message specifi cation DSN distributed sensor network ESC electronic stability control FCD fl oating car data FDM frequency-division multiplexing FH frequency hopping GHG greenhouse gases GPS global positioning system ICT information and communication technologies IoT internet of things KPI key performance indicator M2M machine to machine MAC media access control MEMS microelectromechanical systems MIMO multiple-input multiple-output OEM original equipment manufacturer OFDM orthogonal frequency-division multiplexing OPEX operational expenditure PHY physical layer PV photovoltaic QoS quality of service RES renewable energy source 9List of abbreviations RFID radio-frequency identifi cation SOA service oriented architecture SOAP service oriented architecture protocol TDMA time division multiple access TSMP time synchronized mesh protocol TSP trust, security and privacy UCC urban consolidation centre USN ubiquitous sensor network WIA-FA wireless networks for industrial automation – factory automation WIA-PA wireless networks for industrial automation – process automation WISA wireless interface for sensors and actuators WLAN wireless local area network WMAN wireless metropolitan area network WPAN wireless personal area network WSN wireless sensor network WWAN wireless wide area network XFCD extended fl oating car data Organizations, ABB ABB Group institutions and ARPANET Advanced Research Projects Agency Network companies BBF Broadband Forum CAB Conformity Assessment Board (of the IEC) China-EPRI China Electric Power Research Institute DARPA Defense Advanced Research Projects Agency (USA) ETSI European Telecommunications Standards Institute IEC International Electrotechnical Commission IEEE Institute of Electrical and Electronics Engineers IETF Internet Engineering Task Force ISO International Organization for Standardization ITEI Instrumentation Technology and Economy Institute (China)List of abbreviations ITU-T International Telecommunication Union – Telecommunication Standardization Sector MSB Market Strategy Board (of the IEC) NIST National Institute of Standards and Technology OGC Open Geospatial Consortium OMA Open Mobile Alliance SGCC State Grid Corporation of China SIA Shenyang Institute of Automation (China) SMB Standardization Management Board (of the IEC) UCB University of California Berkeley (USA) W3C World Wide Web Consortium 11Glossary internet of things wireless metropolitan area network IoT WMAN refers to the interconnection of uniquely identifi able also known as a wireless local loop (WLL). WMANs embedded computing-like devices within the are based on the IEEE 802.16 standard. Wireless existing internet infrastructure local loop can reach effective transfer speeds of 1 to 10 Mbps within a range of 4 to 10 kilometres media access control layer MAC layer wireless personal area network part of the data link protocol that controls access WPAN to the physical transmission medium in IEEE 802 a low-range wireless network which covers an area networks (LANs) of only a few dozen metres system on a chip wireless sensor network SoC WSN integrated circuit (IC) that integrates all components self-organizing, multi-hop networks of wireless of a computer or other electronic system into a sensor nodes used to monitor and control physical single chip phenomena time synchronized mesh protocol wireless wide area network TSMP WWAN a networking protocol that forms the foundation wireless network that provides communication of reliable, ultra low-power wireless sensor services to a geographic area larger than a single networking urban area. The most common of all wireless networks wireless local area network WLAN local area network in which data are transferred without the use of wires 12Section 1 Introduction A WSN can generally be described as a network 1.1 Overview of nodes that cooperatively sense and may control Today sensors are everywhere. We take it for the environment, enabling interaction between granted, but there are sensors in our vehicles, persons or computers and the surrounding in our smart phones, in factories controlling CO 2 environment 2. In fact, the activity of sensing, emissions, and even in the ground monitoring processing, and communication with a limited soil conditions in vineyards. While it seems that amount of energy, ignites a cross-layer design sensors have been around for a while, research on approach typically requiring the joint consideration wireless sensor networks (WSNs) started back in of distributed signal/data processing, medium the 1980s, and it is only since 2001 that WSNs access control, and communication protocols 3. generated an increased interest from industrial Through synthesizing existing WSN applications and research perspectives. This is due to the as part of the infrastructure system, potential availability of inexpensive, low powered miniature new applications can be identifi ed and developed components like processors, radios and sensors to meet future technology and market trends. that were often integrated on a single chip (system For instance WSN technology applications for on a chip (SoC)). smart grid, smart water, intelligent transportation The idea of internet of things (IoT) was developed systems, and smart home generate huge amounts in parallel to WSNs. The term internet of things of data, and this data can serve many purposes. was devised by Kevin Ashton in 1999 1 and refers Additionally, as the modern world shifts to this new to uniquely identifi able objects and their virtual age of WSNs in the IoT, there will be a number of representations in an “internet-like” structure. legal implications that will have to be clarifi ed These objects can be anything from large buildings, over time. One of the most pressing issues is the industrial plants, planes, cars, machines, any kind ownership and use of the data that is collected, of goods, specifi c parts of a larger system to human consolidated, correlated and mined for additional beings, animals and plants and even specifi c body value. Data brokers will have a fl ourishing business parts of them. as the pooling of information from various sources While IoT does not assume a specifi c communi- will lead to new and unknown business opportu- cation technology, wireless communication tech- nities and potential legal liabilities. The recent US nologies will play a major role, and in particular, National Security Administration scandal and other WSNs will proliferate many applications and many indignities have shown that there is wide interest in industries. The small, rugged, inexpensive and low gathering data for varied uses. powered WSN sensors will bring the IoT to even One of the more complex issues which arise the smallest objects installed in any kind of envi- within this new world is the thought of machines ronment, at reasonable costs. Integration of these making autonomous decisions, with unknown objects into IoT will be a major evolution of WSNs. impact on the environment or society within which 13Introduction it functions. This can be as simple as a refrigerator 1.2 Scope of this White Paper requesting replenishment for milk and butter at This White Paper is the sixth in a series whose the local store for its owner, or as complex as a purpose is to ensure that the IEC can continue robot that has been programmed to survive in a to contribute through its International Standards harsh environment that originally did not foresee and Conformity Assessment services solving human interaction. It can also be as simple as a global problems in electrotechnology. The White vehicle that records its usage, as does the black Papers are developed by the IEC MSB (Market box in the aerospace industry, but then not only Strategy Board), responsible for analyzing and using the information to understand the cause of understanding the IEC’s market so as to prepare an accident, but also to provide evidence against the IEC to strategically face the future. the owner and operator. For example, a machine that notifi es legal authorities if it was used against the law. It comes to the point where a machine starts acting as if it were a legal entity. The question of liability starts to get fuzzy and the liability question for the “owner” and “operator” of the machine gets more diffi cult to articulate if there is little to no real human intervention in the actions of the machine or robot. This is certainly the worst case scenario, but the question is how to balance the cost of potential liabilities with the benefi ts of IoT solutions? This quickly starts to become more of a societal or ethical, and moral discussion. That is what we usually refer to as generational shifts in values – but the IoT trend will not wait a generation. 14Section 2 History and industrial drivers of WSNs The development of WSNs was inspired by military suitable for highly dynamic ad hoc environments applications, notably surveillance in confl ict zones. and resource-constrained sensor nodes. Further- Today, they consist of distributed independent more, the sensor nodes have been much smaller devices that use sensors to monitor the physical in size (i.e. from that of a pack of cards to dust conditions with their applications extended to particle) and much cheaper in price, and thus industrial infrastructure, automation, health, traffi c, many new civilian applications of sensor networks and many consumer areas. such as environment monitoring, vehicular sensor network and body sensor networks have emerged. Research on WSNs dates back to the early 1980s when the United States Defense Advanced Again, DARPA acted as a pioneer in the new wave Research Projects Agency (DARPA) carried out the of sensor network research by launching an distributed sensor networks (DSNs) programme initiative research programme called SensIT 5 for the US military. At that time, the Advanced which provided the present sensor networks Research Projects Agency Network (ARPANET) with new capabilities such as ad hoc networking, had been in operation for a number of years, dynamic querying and tasking, reprogramming with about 200 hosts at universities and research and multi-tasking. Currently, WSNs have been institutes 4. DSNs were assumed to have many viewed as one of the most important technologies spatially distributed low-cost sensing nodes, for the 21st century 6. China for example has collaborating with each other but operated included WSNs in their national strategic research autonomously, with information being routed to programmes 7. As a result, the commercialization whichever node that can best use the information. of WSNs is accelerating and many new technology Even though early researchers on sensor networks companies are emerging such as Crossbow had the vision of a DSN in mind, the technology was Technology (connecting the physical world to the not quite ready. More specifi cally, the sensors were digital world) and Dust Networks. rather large (i.e. the size of a shoe box and bigger), Today, industrial automation is one of the most and the number of potential applications was thus important areas of WSN applications. According limited. Furthermore, the earliest DSNs were not to Freedonia Group, the global market share of tightly associated with wireless connectivity. sensors for industrial use is 11 billion USD, while Recent advances in computing, communication the cost of installation (mainly cabling costs) and and micro-electromechanical technology have usage is up to more than 100 billion USD. This high resulted in a signifi cant shift in WSN research and cost is the main issue hindering the development brought it closer to the original vision. The new wave of industrial communication technology. WSN of research on WSNs started around 1998 and technology, allowing “ubiquitous sensing” over the has been attracting more and more attention and whole industrial process, can secure the important international involvement. The new wave of sensor parameters which are not available by online network research puts its focus on networking monitoring due to the cost reasons stated above. technology and networked information processing These parameters are important foundations for 15History and industrial drivers of WSNs the implementation of optimal control in order to In today’s market, three-fourths of the industrial achieve the objective of improving product quality, WSN income comes from the process industry; and reducing energy consumption. with the oil and power industry being the fastest growing ones. For example, PetroChina is carrying According to ON World 8, wireless devices to out IoT projects in its oil fi elds, with the purpose be installed in industrial fi elds will increase by to reconstruct 200 000 oil wells. WSN technology 553 % between 2011 and 2016 when there will be applied in the digital conversions of the oil wells will 24 million wireless-enabled sensors and actuators, make use of online monitoring to measure oil well or sensing points, deployed worldwide. Among production and ensure production safety. these, 39 % will be used for new applications that are only possible with wireless sensor networking. In the power industry which is now undergoing By 2014, the number of WSN devices will account the power grid upgrading, WSN technology is also for 15 % of the entire industrial measurement and playing an important role in safety monitoring over control equipment sensing points, and 33 % by power transmission and transformation equipment 2016. and the reconstruction of billions of smart meters. Figure 2-1 Global installed industrial wireless sensing points 8 16History and industrial drivers of WSNs Figure 2-2 Global industrial fi eld instrument shipments, wired and wireless 8 In-plant process 7 500 Oil and gas Power transmission Vertical markets Factory automation 5 000 2 500 2012 2011 Millions 2013 2014 2015 2016 Source: ON World Figure 2-3 WSN revenue growth in all industries 8 17Section 3 WSN technology hop routing, and fi nally reach the management 3.1 Characteristic features node through the internet or satellite. It is the user of WSNs who confi gures and manages the WSN with the A WSN can generally be described as a network management node, publish monitoring missions of nodes that cooperatively sense and control the and collection of the monitored data. environment, enabling interaction between persons As related technologies mature, the cost of or computers and the surrounding environment 2. WSN equipment has dropped dramatically, and WSNs nowadays usually include sensor nodes, their applications are gradually expanding from actuator nodes, gateways and clients. A large the military areas to industrial and commercial number of sensor nodes deployed randomly inside fi elds. Meanwhile, standards for WSN technology of or near the monitoring area (sensor fi eld), form ®1 have been well developed, such as Zigbee , networks through self-organization. Sensor nodes monitor the collected data to transmit along to other ® 1 Zigbee is an example of a suitable product available sensor nodes by hopping. During the process of commercially. This information is given for the convenience transmission, monitored data may be handled by of users of this standard and does not constitute an multiple nodes to get to gateway node after multi- endorsement by IEC of this product. Figure 3-1 Wireless sensor networks 19WSN technology Figure 3-2 Market size of WSN applications 9 WirelessHart, ISA 100.11a, wireless networks module) then transfers the data, so that the physical for industrial automation – process automation realization of communication can be achieved. (WIA-PA), etc. Moreover, with new application It is important that the design of the all parts of a modes of WSN emerging in industrial automation WSN node consider the WSN node features of tiny and home applications, the total market size of size and limited power. WSN applications will continue to grow rapidly. 3.2.1 Miniaturization technology 3.2 Sensor nodes of sensor based on MEMS The sensor node is one of the main parts of a WSN. The miniaturization technology of WSN nodes The hardware of a sensor node generally includes based on microelectromechanical systems (MEMS) four parts: the power and power management has made remarkable progress in recent years. module, a sensor, a microcontroller, and a wireless The core technology of MEMS is to realize the transceiver, see Figure 3-3. The power module combination of microelectronics technology, micro- offers the reliable power needed for the system. machining technology and the packaging tech- The sensor is the bond of a WSN node which can nology. Different levels of 2D and 3D micro- obtain the environmental and equipment status. A sensitive structures can be produced based on sensor is in charge of collecting and transforming microelectronics and micro-machining technology, the signals, such as light, vibration and chemical which can be the miniature sensing elements. These signals, into electrical signals and then transferring miniature sensing elements, associated power them to the microcontroller. The microcontroller supply and signal conditioning circuits can be inte- receives the data from the sensor and processes grated and packaged as a miniature MEMS sensor. the data accordingly. The Wireless Transceiver (RF 20WSN technology Power and power management Sensor Microcontroller Transceiver Figure 3-3 Hardware structure of a WSN sensor node At present, there are already many types of miniature Some companies have begun to commercialize MEMS sensors in the market which can be used to sensor network applications using energy acqui- measure a variety of physical, chemical and biomass sition devices. For example, the German compa- signals, including displacement, velocity, accelera- ny EnOcean has provided light energy harvesting tion, pressure, stress, strain, sound, light, electric- devices, vibration energy harvesting devices and ity, magnetism, heat, pH value, etc. 10. In 2003, temperature-based energy harvesting devices for researchers at the University of California Berkeley smart building lighting and air monitoring appli- (UCB) developed a WSN sensor node (mote) with a cations. For equipment and construction health micro sensor. The actual size of its MEMS sensing monitoring applications, a variety of piezoelectric module was only 2.8 mm × 2.1 mm 11. vibration energy harvesting products have entered the market. The British company of Perpetuum provides a series of products that converts mechan- 3.2.2 Ambient energy harvesting ical vibration into electrical energy used to perpetu- technology ally power autonomous, maintenance-free industrial wireless sensor nodes. For these sensor nodes the Nodes need an energy source, and ambient energy of vibration made by your fi ngers knock- energy harvesting from external sources are used ing the desk can support the sensor node sending to power small autonomous sensors such as those 2 kB data to 100 m away every 60 seconds. based on MEMS technology. These systems are often very small and require little power, however For the monitoring applications of piping systems, their applications are limited by the reliance on a large number of products based on temperature battery power. difference energy harvesting have been developed. Nextreme Company’s products can produce Ambient energy harvesting cannot only be realized 0.25 W of power by a temperature difference of by conventional optical cell power generation, 60 °C in an area of 3.2 mm × 1.6 mm energy but also through miniature piezoelectric crystals, harvesting materials. Figures 3-4 and 3-5 show micro oscillators, thermoelectric power generation some sensor nodes confi gured with ambient elements, or electromagnetic wave reception energy harvesting devices. devices 12 13. 21