Basics of Wireless Sensor Network

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1 Basics of Wireless Sensor Network

2 A sensor network is an infrastructure contain sensing (measuring), computing and communication elements that gives an administrator the ability to device to observe and react to events in a specified environment. There are four basic components in a sensor network: An Assembly of distributed or localized sensors An interconnecting network (usually wireless-based) A Central point of information clustering A set of computing resources at the central point to handle data correlation, event movement, status querying & data mining.

3 The technology for sensing and control includes Electric and magnetic field sensors; Radio-wave frequency sensors Optical-, electrooptic- and infrared sensors; Radars; lasers; location/navigation sensors; Seismic and pressure-wave sensors; Environmental parameter sensors (e.g., wind, humidity, heat); Biochemical national security oriented sensors. Today s sensors can be described as smart inexpensive devices equipped with multiple onboard sensing elements; they are low-cost, low-power,multifunctional nodes. Sensor devices or wireless nodes (WNs) are also called motes. Sensors are internetworked via a series of multihop shortdistance low-power wireless links

4 Wireless Sensor Networks are networks that consists of sensors which are distributed in an adhoc manner. These sensors work with each other to sense some physical phenomenon and then the information gathered is processed to get relevant results. Wireless sensor networks consists of protocols and algorithms with self-organizing capabilities. Introduction to Wireless Sensor Networks 4

5 A wireless sensor network (WSN) is a wireless network consisting of spatially distributed autonomous devices using sensors to cooperatively monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants, at different locations. - Wikipedia

6 Formed by hundreds or thousands of motes that communicate with each other and pass data along from one to another Research done in this area focus mostly on energy aware computing and distributed computing Links to Other networks or Similar Super Nodes Super Node Motes

7 Environmental/Habitat monitoring Acoustic detection Seismic Detection Military surveillance Inventory tracking Medical monitoring Smart spaces Process Monitoring

8 Energy Efficiency Limited storage and computation Low bandwidth and high error rates Errors are common Wireless communication Noisy measurements Node Failure are expected Scalability to a Large Number of Sensor Nodes Introduction to Wireless Sensor Networks 11

9 Power efficiency in WSNs is generally accomplished in three ways: 1. Low-duty-cycle operation. 2. Local/in-network processing to reduce data volume 3. Multihop networking reduces the requirement for long-range transmission since signal path loss is an inverse exponent with range or distance. Each node in the sensor network can act as a repeater, thereby reducing the link range coverage required and, in turn, the transmission power.

10 MANET MANETs are based on point-to-point communications. They are mobile this is not generally the case in MANETs. this is not always the case in MANETs, where the communicating devices handled by human users can be replaced or recharged relatively often. The number of sensor nodes in a MANET network are less. WSN sensor nodes use primarily multicast or broadcast communication, Sensors generally are not mobile Because the data being collected by multiple sensors are based on common phenomena, there is potentially a degree of redundancy in the data being communicated by the various sources in WSNs; A critical resource constraint in WSNs is energy; The number of sensor nodes in a sensor network can be several orders of magnitude higher than the nodes in a MANET.

11 Battery Memory CPU Wireless Transceiver Sensors Enabled by recent advances in MEMS technology Integrated Wireless Transceiver Limited in Energy Computation Storage Transmission range Bandwidth Sensing Hardware DAWN Lab / UMBC 14

13 DAWN Lab / UMBC 16

14 DAWN Lab / UMBC 17

15 Applications of Sensor Networks Military applications Monitoring inimical forces Monitoring friendly forces and equipment Military-theater or battlefield surveillance Targeting Battle damage assessment Nuclear, biological, and chemical attack detection Environmental applications Microclimates Forest fire detection Flood detection Precision agriculture 18

16 Applications of Sensor Networks continue Health applications Remote monitoring of physiological data Tracking and monitoring doctors and patients inside a hospital Drug administration Elderly assistance Home applications Home automation Instrumented environment Automated meter reading Commercial applications Environmental control in industrial and office buildings Inventory control Vehicle tracking and detection Traffic flow surveillance 19

19 Roles of participants in WSN Sources of data: Measure data, report them somewhere Typically equip with different kinds of actual sensors Sinks of data: Interested in receiving data from WSN May be part of the WSN or external entity, PDA, gateway, Actuators: Control some device based on data, usually also a sink 22

20 Network Architectures Base Statio n Layered Architecture Clustered Architecture Base Statio n Layer 1 Layer 2 Layer 3 Larger Nodes denote Cluster Heads Advanced Techniques of Mobile DAWN Ad Hoc Lab and / Wireless UMBCSensor Networks 23

21 Protocol Stack for sensor Network 25

22 WSN Protocol Stack Layer Name Upper layers Working In-network applications, including application processing, data aggregation, external querying query processing, and external database Layer 4 Transport, including data dissemination and accumulation, caching, and storage Layer 3 Networking, including adaptive topology management and topological routing Layer 2 Layer 1 Link layer (contention): channel sharing (MAC), timing, and locality Physical medium: communication channel, sensing, actuation, and signal processing 26

23 WSN Sensor types( Categories) Category 1 WSNs (C1WSNs) Category 2 WSNs (C2WSNs) mesh-based systems with multihop radio connectivity among or between WNs Utilizing dynamic routing in both the wireless and wireline portions of the network. support highly distributed high-nodecount applications (e.g., environmental monitoring, national security systems); C1WSNs tend to deal with large-scale multipoint-to-point systems with massive data flows, whereas Point-to-point or multipoint-to-point (starbased) systems generally with single-hop radio connectivity to WNs Utilizing static routing over the wireless network; typically, there will be only one route from the WNs to the companion terrestrial or wireline forwarding node C2WSNs typically support confined short-range spaces such as a home, a factory, a building, or the human body. C2WSN technology for short-range low-data-rate wireless applications such as RFID (radiofrequency identification) systems, light switches, fire and smoke detectors, thermostats, and, home appliances. 27

24 Category-1 WSN Architecture 30

25 Category 2-WSN architecture 31

26 EXAMPLES OF CATEGORY 2 WSN APPLICATIONS 1. Home Application 2. Building Automation 3. Industrial Automation 4. Medical Application 32

27 Home Control Automation 33

28 Home Control Automation Sensing applications facilitate management of lighting, heating, and cooling systems from anywhere in the home. Sensing applications automate control of multiple home systems to improve conservation, convenience, and safety. Sensing applications capture highly detailed electric, water, and gas utility usage data. Sensing applications embed intelligence to optimize consumption of natural resources. Sensing applications enable the installation, upgrading, and networking of a home control system without wires. Sensing applications enable one to configure and run multiple systems from a single remote control. Sensing applications support the straightforward installation of wireless sensors to monitor a wide variety of conditions. Sensing applications facilitate the reception of automatic notification upon detection of unusual events. 34

29 Building Automation 35

30 Building Automation Sensing applications integrate and centralize management of lighting, heating, cooling, and security (e.g., see Figure 2.6). Sensing applications automate control of multiple systems to improve conservation, flexibility, and security. Sensing applications reduce energy expenses Sensing applications enable one to allocate utility costs equitably based on actual consumption. Sensing applications enable the rapid reconfiguring of lighting systems to create adaptable workspaces. Sensing applications enable the extension and upgrading of building infrastructure with minimal effort. 36

31 Industrial Control Application 37

32 Industrial Control Application Industrial automation applications provide control, conservation, efficiency, and safety, as follows: Sensing applications improve asset management by continuous monitoring of critical equipment. Sensing applications reduce energy costs through optimized manufacturing processes. Sensing applications help identify inefficient operation or poorly performing equipment. Sensing applications help automate data acquisition from remote sensors to reduce user intervention. Sensing applications provide detailed data to improve preventive maintenance programs. Sensing applications help deploy monitoring networks to enhance employee and public safety. Sensing applications help data collection for improved compliance reporting. 38

33 Applications for Industrial and Commercial Spaces Include Warehouses, fleet management, factories, supermarkets, office complexes Gas, wat Smoke, CO, and HO detectors Refrigeration cage or appliance Equipment management services and preventive maintenance Security services Lighting control Assembly line and workflow and inventory Materials processing systems (heat, gas flow, cooling, chemical) Remote monitoring from corporate headquarters of assets, billing, and energy management 39

34 Medical Application 40

35 Medical Application A number of hospitals and medical centers are exploring applications of WSN technology to a range of medical applications, including pre-hospital and in-hospital emergency care, disaster response, and stroke patient rehabilitation. WSNs have the potential to affect the delivery and study of care by allowing vital signs to be collected and integrated automatically into the patient care record and used for real-time triage, correlation with hospital records, WSNs permit home monitoring for chronic and elderly patients, facilitating long-term care and trend analysis; This in turn can sometimes reduce the length of hospital stays. WSNs also permit collection of long-term medical information that populates databases of clinical data; this enables studies across populations and allows physicians to study the effects of medical intervention programs 41

36 EXAMPLES OF CATEGORY 1 WSN APPLICATIONS Military sensor networks to detect and gain as much information as possible about enemy movements, explosions, and other phenomena of interest Law enforcement and national security applications for inimical agent tracking or nefarious substance monitoring (e.g., see Figure 2.9) 42

37 Law enforcement and national security applications 43

38 EXAMPLES OF CATEGORY 1 WSN APPLICATIONS Sensor networks to detect and characterize chemical, biological, radiological, nuclear, and explosive (CBRNE) attacks and material Sensor networks to detect and monitor environmental changes in plains, forests, oceans, and so on Wireless traffic sensor networks to monitor vehicle traffic on highways or in congested parts of a city Wireless surveillance sensor networks for providing security in shopping malls, parking garages Wireless parking lot sensor networks to determine which spots are occupied and which are free Borders monitoring with sensors and satellite uplinks 44

39 Highway Monitoring Application 45

40 Highway Monitoring Application Traffic Pulse is targeted for open-air environments; it provides real-time collection of data (e.g., to check temperature or monitor pollution levels). The system is installed along major highways; the digital sensor network gathers lane-by-lane data on travel speeds, lane occupancy, and vehicle counts. These basic data elements make it possible to calculate average speeds and travel times. The data are then transmitted to the data center for reformatting. In each major city, Traffic.com maintains a traffic pulse operations center that collects and reports on real-time event, construction, and incident data. 46

41 Military Applications 47

42 Military Applications Condition-Based Monitoring Military Surveillance Borders Monitoring 48

43 Civil and Environmental Engineering Applications Sensors can be used for civil engineering applications. Research has been under way in recent years to develop sensor technology that is applicable for buildings, bridges, and other structures. The goal is to develop smart structures that are able to selfdiagnose potential problems and self-prioritize requisite repairs This technology is attractive for earthquake-active zones. Although routine mild tremors may not cause visible damage, they can give rise to hidden cracks that could eventually fail during a higher-magnitude quake. Furthermore, after a mild earthquake, a building s true structural condition may be visible through Smart Dust motes, tiny and inexpensive sensors 50

44 Wildfire Instrumentation Application Collecting real-time data from wild fires is important for life safety considerations and allows predictive analysis of evolving fire behavior. One way to collect such data is to deploy sensors in the wildfire environment. FireBugs are small wireless sensors (motes) based on TinyOS that self-organize into networks for collecting real-time data in wildfire environments 51

45 Habitat Monitoring Application Monitoring of sensitive wildlife and habitats. About three dozen motes were deployed on the island. Each mote has a microcontroller, a low-power radio, memory, and batteries. Sensor motes monitor and relay their readings into a satellite link that allows researchers to download real-time environmental data over the Internet. For habitat monitoring the planner needed sensors that can take readings for temperature, humidity, barometric pressure, and midrange infrared. Motes sample and relay their sensor readings periodically to computer base stations on the island 52

References. The vision of ambient intelligence. The missing component...

References. The vision of ambient intelligence. The missing component... References Introduction 1 K. Sohraby, D. Minoli, and T. Znadi. Wireless Sensor Networks: Technology, Protocols, and Applications. John Wiley & Sons, 2007. H. Karl and A. Willig. Protocols and Architectures