Industrial Wireless Sensor Networks Challenges, Design Principles, and Technical Approaches

1. Industrial Wireless Sensor NetworksChallenges, Design Principles, and Technical Approaches Presented By: JesminJahanTithi Std no: 0409052065 S.M.Arifuzzaman

2. Outline • WSN (Wireless Sensor Network) • Industrial Monitoring • Applications of WSN in Industry • Challenges & Design Goals • Standardized Activities • Open Issues

3. Wireless Sensor Network • consists of spatially distributed autonomous sensors • cooperatively monitor physical or environmental conditions • such as temperature, sound, vibration, pressure, motion or pollutants

4. Wireless Sensor Network Sensor

5. Applications of WSN • military applications e.g. battlefield surveillance • environment and habitat monitoring • health monitoring & healthcare applications • home automation • traffic control • industrial process monitoring and control machine

6. Wireless Sensor Network at Industries

7. Industrial Monitoring and Controlling • Three types of monitoring • Process monitoring • Staff monitoring • Machineries monitoring and controlling • companies often use manual labor-intensive techniques. • increases the cost • human errors

8. Industrial Monitoring and Controlling and Sensors • some monitoring process can not be done by human beings • they are out of reach • it is dangerous to monitor them directly ( for example because of RF interference/Highly caustic or corrosive environments/High humidity levels /Vibrations /Dirt and dust) Without sensors these types of monitoring are very difficult or impossible!!

9. Applications of WSN in Industry • Building automation • Building access controls , HVAC controls , Lighting controllers, Thermostat , Lifts / Elevators / Escalators , Remote alarm triggering , Water Management, Electrical blinds

10. Applications of WSN in Industry • Industrial process automation • Water/Wastewater Monitoring • Landfill Ground Well Level Monitoring and Pump Counter • Flare Stack Monitoring • Water Tower Level Monitoring • Vehicle Detection • Agriculture • Windrow Composting • Greenhouse Monitoring

11. Applications of WSN in Industry • Electric utility automation • Monitoring device parameters • Automatic meter reading • Inventory management • Monitoring the inventory product conditions and environment

12. Machine Health Monitoring or Condition based maintenance • Condition-based maintenance (CBM) -significant cost savings and enable new functionalities. • US Navy shipboard systems -reduced manning levels -automated maintenance monitoring systems. Inaccessible locations, rotating machinery, hazardous or restricted areas, and mobile assets can now be reached with wireless sensors.

13. What happens at Industry • Wireless tiny sensor nodes are installed on industrial equipment • Sensors monitor the parameters critical to each equipment • based on a combination of measurements such as vibration, temperature, pressure, and power quality

14. What happens at Industry (contd.) • Data are then wirelessly transmitted to a sink node that analyzes the data from each sensor • Any potential problems are notified to the plant personnel as an advanced warning system. • This enables plant personnel to repair or replace equipment before their efficiency drops or they fail entirely. • In this way, catastrophic equipment failures and the associated repairing can be prevented in advance.

15. Challenges, Design Goals and State of Art Conditions of WSN & IWSN

16. Challenge: Resource constraints • Constraints • Battery energy • Limited memory • Limited Processing Capabilities • Bandwidth constraint

17. Design Goal: Resource-efficient design • Energy saving with energy-efficient protocols • Energy-aware routing on network layer • Energy-saving mode on MAC layer • For certain FEC (forward error correction) codes, hop-length extension decreases energy consumption • Hardware optimizations • Sleeping schedules to keep electronics inactive most of the time, dynamic optimization of voltage, and clock rate • System-on-chip (SOC) technology for low power consumption by integrating a complete system on a single chip ( ZigBee SOC, CC2430, EM250) • Local data processing

18. Design Goal: Resource-efficient design • Energy Recovery/Acquisition: Energy harvesting technique • Extracts energy from environment Some approaches • Photovoltaic cell with rechargeable battery • Background radio signal: small energy • vibrations, thermoelectric conversion, human body • RF signal transmission: safety issue • employing piezoelectric materials

19. Challenge: Data redundancy • High Density in network topology cause redundant data in both spatial and temporal domain • Spatial correlation: redundant data possibly from nearby sensors • Temporal correlation: redundant data from consecutive observation

20. Design Goals: Data fusion and localized processing Data aggregation and fusion • Locally filter the sensed data and transmit only the processed one • Only necessary information is transported to the end-user Intermediate node checks the contents of incoming data and then combines them by eliminating redundant information under some accuracy constraints

21. Challenge: Packet errors and variable-link capacity • Attainable capacity and delay at each link depends on • Location • Interference level perceived at the receiver • Varying characteristics of the link over space and time due to obstructions and noisy environment • High bit error rates

22. Interference • Broadband interference • Generated by motors, inverters, computers, electric-switch contacts, voltage regulators, pulse generators, thermostats, and welding equipment • Have constant energy spectrum over all frequencies and high energy • Emitted unintentionally from radiating sources • Narrowband interference • Intentional and have less Energy • Caused by UPS system, electronic ballasts, test equipment, cellular networks, radio–TV transmitters, signal generators, and micro wave equipment

23. Design Goals: Fault tolerance and reliability • Sensed data should be reliably transferred to the sink node (specially mission-critical information) • Programming/command and queries should be reliably delivered to the target sensor node to assure the proper functioning • To combat the unreliability, verification and correction on each communication layer are required • automatic repeat request (ARQ): not suitable for real time system • forward error correction (FEC) • hybrid schemes.

24. Design Goal: Fault tolerance and reliability • Forward error correction (FEC) • Improve the error resiliency more than ARQ • Radio-modulation techniques to reduce interferences and improve reliability • Direct- sequence spread spectrum • Frequency-hopping spread spectrum Benefits of SSM: • Multiple access • Anti-multipath fading • Anti jamming

25. Challenge:Security Security for externalattacks and intrusion • Passive attacks: eavesdropping on transmissions , traffic analysis, disclosure of message contents • Active attacks: modification, fabrication, and interruption (in case of IWSN, node capturing, routing attacks, or flooding) • External denial-of-service attacks and intrusion

26. Design Goal:Secure design • Low level and high level security should be addressed • key establishment and trust control, secrecy and authentication, privacy, robustness to communication DoS, secure routing, resilience to node capture • secure group management, intrusion detection, secure data aggregation • Security overhead should be balanced against QoS

27. Challenge:Dynamic topologies and harsh environmental conditions In harsh industrial environments, the topology and connectivity of the network may vary due to • link and sensor-node failures • a portion of sensor nodes to malfunction

28. Design Goal: Adaptive network operation • Adaptability enables to cope with dynamic wireless-channel conditions and new connectivity requirements for new industrial processes • Adaptive signal-processing algorithms and communication protocols are required to balance the trade offs among • Resources • Accuracy • Latency • time synchronization requirements

29. Challenge: Quality-of-service requirements • Accuracy between the data reported and what is actually occurring in the industrial environment • Time sensitive data should be reached in a timely manner • Different IWSNs have different QoS requirements and specifications

30. Design Goal: Application-specific design and Time synchronization • Designs and techniques should be based on the application-specific QoS requirements • Existing time synchronization strategies designed for other traditional wired and wireless networks maynot be appropriate for IWSNs dueto: • resource and size limitations • lack of a fixed infrastructure • dynamic topologies • Adaptive and scalable time-synchronization protocols are required for IWSNs

31. Challenge: Large-scale deployment and ad hoc architecture • Large number of sensor nodes • Randomly spread over the deployment field • Need for autonomous establishment of connections and maintenance of network connectivity

32. Design Goal: Low-cost and small sensor nodes and Self-configuration and self-organization • To accomplish large scale deployments feasible hardware cost should be minimized • Commercial release: • Smart Dust motes • uAMPS • CC2430 and EM250 • ZigBee SOC • self-organizing architectures and protocols are required for • supporting the dynamic topologies caused by node failure/mobility/ temporary power-down/addition of new nodes • large-scale node deployments

33. Challenge: Integration with Internet and other networks IWSN needs to provide service for querying the network to retrieve useful information from anywhere and anytime • Should be remotely accessible from the Internet • Need to be integrated with the Internet Protocol(IP) architecture

34. Design Goal: Scalable architectures and efficient protocols • Needs to support heterogeneous industrial applications • necessary to develop flexible and scalable architectures to accommodate the requirements of various applications in the same infrastructure • Modular and hierarchical systems • Interoperability with existing legacy solutions such as fieldbus and Ethernet-based systems

35. Software development: API • Should be accessible through a simple application programming interface • Should make the underlying network complexity transparent to the end users • Should be able to integrate seamlessly with the legacy fieldbus

36. Software development: Operating System and Middleware Design • Operating system should balance the tradeoff between energy and QoS requirements • Tiny OS • component-based development • flexible platform for implementing new communication protocols • supports communication, multitasking, and code modularity • Middleware should provide efficient network and system management • abstracts the system as a collection of massively distributed objects • enables industrial sensor applications to originate queries and tasks, • gather responses and results, • monitors the changes within the network

37. Software: System Installation and Commissioning • During installation, what and where a sensor will monitor, should be indicated • Network management and commissioning tools should be provided by software • for example: a graphical user display to show network connectivity and help to set the operational parameters • Network performance analysis and other management features • detecting failed nodes, assigning sensing tasks, monitoring network health, upgrading firmware, and providing QoS provisioning

38. Network Architecture • Network should be scalable • Flexible and hierarchical architectures • should accommodate the requirements of both heterogeneous and homogeneous infrastructure • flat single-tier network of homogeneous sensor nodes • Multi-tier heterogeneous approaches (clustering/partitioning) • resource-constrained low-power elements are in charge of performing simpler tasks, such as detecting scalar physical measurements • resource-rich high-power devices (such as gateways) perform more complex tasks

39. Cross-Layer Design • IWSNs demands • Cross layer optimization (physical, MAC, and routing layers optimization) due to • Technical challenges caused by harsh industrial conditions • Application specific QoS requirements • Methodologies to • Leverage potential improvements of exchanging information between different layers of the communication stack • Some form of logical separation of these functionalities should be kept to preserve modularity

40. Standardization Activities • ZigBee • A mesh-networking standard based on IEEE 802.15.4 radio technology • Targeted at industrial control and monitoring, building and home automation, embedded sensing, and energy system automation • Advantages • Extremely low energy consumption • Support different topologies • Disadvantage • Cannot serve the high number of nodes within the specified cycle time

41. Standardization Activities • Wireless HART • Specifically designed for process monitoring and control • Employs IEEE 802.15.4-based radio, frequency hopping, redundant data paths, and retry mechanism • Utilize mesh networking, both transmission and relay

42. Standardization Activities • UWB • Short-range transmission of very short impulses emitted in periodic sequences • Used in Multimedia and personal area networking, now trying in industries Advantages: • Good localization capabilities • Share previously allocated radio frequency bands by hiding signals under noise floor • Transmit high data rates with low power • Good security characteristics • Ability to cope with multipath environments

43. Standardization Activities: UWB (Cont.) Disadvantage: • Not viable for longer distance communication or measuring data from unsafe zone Challenges: • Hardware development • Handling MAC and multipath interference • Understanding propagation characteristics

44. Standardization Activities (Cont..) • IETF6LoWPAN • Aims for standard IP communication over low power wireless IEEE 802.15.4 networks utilizing IPV6 Advantages : • Communicate directly with other IP in wireless sensor devices • Established application level model and services (e.g., HTTP, HTML, XML) • Established network-management tools • Transport protocols • Support for IP option

45. Standardization Activities (Cont..) • ISA100 • Targeted for reliable communication system for monitoring and control applications • Bluetooth and Bluetooth Low Energy • Ultralow-power technology address very low battery capacity

46. Open Issues • To devise analytical models • to evaluate and predict IWSNs performance characteristics, such as communication latency and reliability and energy efficiency • Optimal sensor-node deployment • localization, security, and interoperability between different IWSN manufacturers

47. Open Issues • To cope with RF interference and dynamic wireless channel conditions in industrial environments • Porting a cognitive radio paradigm to a low power industrial sensor node • Developing controlling mechanisms for channel hand-off • Because of the diverse industrial application requirements and large scale of the network, several technical problems still remain to be solved in analytical IWSN models

48. Possible Solutions ? ? ?