INDUSTRIAL WIRELESS SENSOR NETWORKS

CHALLENGES, DESIGN PRINCIPLES, AND TECHNICAL APPROACHES

Presented By:

Jesmin Jahan Tithi

Std no: 0409052065

S.M.Arifuzzaman

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OUTLINE

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

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WIRELESS SENSOR NETWORK•consists of spatially distributed autonomous sensors

•cooperatively monitor physical or environmental conditionssuch as temperature, sound, vibration, pressure, motion or pollutants

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WIRELESS SENSOR NETWORK

Sensor

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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

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WIRELESS SENSOR NETWORK AT INDUSTRIES

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INDUSTRIAL MONITORING AND CONTROLLING

Three types of monitoringProcess monitoringStaff monitoringMachineries monitoring and controlling

companies often use manual labor-intensive techniques. • increases the cost • human errors

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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!!

Without sensors these types of monitoring are

very difficult or impossible!!

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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

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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

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Electric utility automation Monitoring device parameters

Automatic meter reading

Inventory management Monitoring the inventory product conditions and

environment

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APPLICATIONS OF WSN IN INDUSTRY

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.

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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

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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.14

CHALLENGES, DESIGN GOALS AND STATE OF ART

CONDITIONS OF WSN & IWSN

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CHALLENGE: RESOURCE CONSTRAINTS

Constraints Battery energy Limited memory Limited Processing Capabilities Bandwidth constraint

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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 17

DESIGN GOAL: RESOURCE-EFFICIENT DESIGN

Energy Recovery/Acquisition: Energy harvesting techniqueExtracts 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

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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

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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

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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

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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 22

INTERFERENCE

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.

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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 fadingAnti jamming

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CHALLENGE: SECURITYSecurity for external attacks 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

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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

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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

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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

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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

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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 may not be appropriate for IWSNs due to: resource and size limitations lack of a fixed infrastructure dynamic topologies

Adaptive and scalable time-synchronization protocols are required for IWSNs 30

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

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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

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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

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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

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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

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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

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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

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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 38

CROSS-LAYER DESIGN

IWSNs demandsCross 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

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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 40

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

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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 environments42

STANDARDIZATION ACTIVITIES: UWB (Cont.)

Disadvantage: Not viable for longer distance communication or measuring data

from unsafe zone

Challenges:Hardware developmentHandling MAC and multipath interferenceUnderstanding propagation characteristics

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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

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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

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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

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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

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POSSIBLE SOLUTIONS

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