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Ubiquitous Healthcare Using MAC Protocols in Wireless Body Area Sensor Networks (WBASNs)

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Group Members Muhammad Sarim Hayat FA08-BET-131 Nadir Ali KhanFA08-BET-089 Umair Rafiq FA08-BET-132

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OUTLINE Abstract Introduction Summary of Architectures of WBANs Energy Efficient MAC Protocols MAC Frame structure Path Loss in WBAN Conclusion

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OUTLINE Abstract Introduction Summary of Architectures of WBANs Energy Efficient MAC Protocols MAC Frame structure Path Loss in WBAN Conclusion

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Abstract(1/2) Wireless Body Area Sensor Networks (WBASNs) Ubiquitous Healthcare (UHC) o Survey of different architectures of WBANs o Functionality of devices used in architectures Survey of different MAC protocols used in WBASNs o Advantages and disadvantages is discussed o Trade-offs o Mechanisms used by different protocols o Analyses of different MAC protocols with respect to different architectures used in UHC

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Abstract(2/2) Path loss in WBAN o In-body Communication With respect to MAC Protocols With respect to WBAN models o On-body Communication With respect to MAC Protocols With respect to distance, amplitude and RMS delay o Off-body communication With respect to MAC Protocols

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OUTLINE Abstract Introduction Summary of Architectures of WBANs Energy Efficient MAC Protocols MAC Frame structure Path Loss in WBAN Conclusion

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Introduction (1/3) WBASNs o Emerging domain of wireless communication o A lot of advancement in this domain o Consists of tiny sensors UHC o Provided to patients all around the globe, especially to elderly peoples o Different architectures are discussed o Each architecture has its own applications depending upon the communication scenarios

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Introduction (2/3) Energy Efficiency of the system o One of the basic requirement for WBASNs because of limited power of batteries o Life time of a node depends upon: Energy consumption during communication Energy wastage during communication Packet collision Overhearing Idle listening Over emitting Control overhead

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Introduction (3/3) Path loss o Data is transferred through wireless medium so path loss is probable to occur o Path loss is different for different scenarios and it depends upon: Frequency of operations Distance between transmitter and receiver nodes (d)

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Most Frequently Used Standards for WBAN Communication IEEE 802.15.1 Bluetooth ZigBee Medical Implant Communications Service (MICS) IEEE 802.15.6 Ultra Wide Band (UWB)

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Wearable Sensors used for Ubiquitous HealthCare Wrist watch (eWatch) Oximeter Chest belt Wearable shirt type (smart shirt/life shirt)

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General WBAN Architecture

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OUTLINE Abstract Introduction Summary of Architectures of WBANs Energy Efficient MAC Protocols MAC Frame structure Path Loss in WBAN Conclusion

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OUTLINE Abstract Introduction Summary of Architectures of WBANs Energy Efficient MAC Protocols MAC Frame structure Path Loss in WBAN Conclusion

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Energy Efficient MAC Protocols MAC Layer is the most suitable layer for discussing energy and power issues Collision avoidance for energy efficiency, minimum latency, high throughput, and communication reliability, are basic requirements in the design of MAC protocol. There are several sources of energy wastage:

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Energy minimization techniques in MAC Protocols for WBANs (1/2) There are three main approaches adopted for the energy saving mechanisms in MAC protocols for WBANs, which are listed and discussed below: o Low Power Listening (LPL) Node awakes for a very short period to check activity of channel If the channel is not idle then the node remains in active state to receive data and other nodes go back to sleeping mode. LPL is sensitive to traffic rates

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Energy minimization techniques in MAC Protocols for WBANs (2/2) o Scheduled Contention Combination of the scheduling and contention based mechanisms In Contention based protocols, contending nodes try to access the channel for data transmission Scheduling or Contention free means that each node has the schedule of transmission in the form of bandwidth or time slot. o Time Division Multiple Access (TDMA) Time slots are allocated to the sensor nodes by a master node (MN). This scheme is highly sensitive to clock drift The scheme is power efficient because a node gets time slot for transmission of data and remains in sleep mode for rest of the time

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Advantages and disadvantages of MAC Protocols

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Energy minimization mechanism in MAC protocols

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Performance Trade-offs made by MAC Protocols

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Observations o For Static Topology in WBANs Ta-MAC is best suited for Traffic System Architecture of WBASNs used for UHC It uses different mechanisms for on demand, emergency and normal traffics o For Dynamic Topology in WBANs B-MAC is best suited for all other architectures of WBASNs

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OUTLINE Abstract Introduction Summary of Architectures of WBANs Energy Efficient MAC Protocols MAC Frame structure Path Loss in WBAN Conclusion

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MAC Frame structure(1/2) MAC frame structure consists of control portion or control packet and data portion. Control portion is responsible for the management and control messages Data portion consist of two sub parts: o Contention Access Period (CAP) o Contention Free Period (CFP)

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MAC Frame structure(2/2)

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Comparison Between IEEE 802.15.4 MAC and Original

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Data Traffic Control

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OUTLINE Abstract Introduction Summary of Architectures of WBANs Energy Efficient MAC Protocols MAC Frame structure Path Loss in WBAN Conclusion

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Path Loss in WBAN (1/2) WBASNs is greatly influenced by the amount of path loss that occurs due to different impairments. Devices for WBASNs are generally placed inside or on the body surface. Reduction in power density of an electromagnetic wave introduces path loss.

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Path Loss in WBAN (2/2) The path loss model in dB between the transmitting and the receiving sensor nodes as a function of the distance d is computed by as:

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Scenarios of Path loss Three scenarios of Path loss: In-Body Communication On-Body Communication Off-Body Communication

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Nodes to Calculate Path Loss in WBAN Implant node Body Surface node External node

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Effect of WBASN Antennas Electrical antennas, such as dipole Magnetic antennas, such as loop

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Characteristics of Human Body Not Ideal Medium for Communication Human body consists of materials with different dielectric, thickness and impedance It encounters impairments due to different frequency of operation

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Pathloss models for In-Body Communication In-Body Communication o Deep Implant to On-Body o Near Surface Implant to On-body o Deep Implant to Implant o Near Surface Implant to Implant

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Implant to Implant Implant to Body Surface

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Path loss in different models of WBAN

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Summary of In-Body Path Loss in WBAN

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Amplitude Attenuation in On-Body

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Path Loss VS Distance for On-Body Communication

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RMS Delay at 15cm Separation

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RMS Delay at 45cm Separation

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Summary of On-Body Path Loss in WBAN

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OUTLINE Abstract Introduction Summary of Architectures of WBANs Energy Efficient MAC Protocols MAC Frame structure Path Loss in WBAN Conclusion

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Conclusion(1/3) Wireless Body Area Sensor Networks (WBASNs) o Emerging domain in Wireless Communication o Most important application is Ubiquitous Healthcare (UHC) Survey is done on: o General Architectures used in WBAN for UHC o Devices and their Functionality o MAC protocols used in WBAN o Advantages and Disadvantages of MAC protocols and their tradeoffs

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Conclusion(2/3) Path Loss in WBAN o In-Body Communication o On-Body Communication o Off-Body Communication We conclude that o For Static Topology in WBAN Ta-MAC is best suited for Traffic System Architecture of WBASN used for UHC o For Dynamic Topology in WBAN B-MAC is best suited for all other architectures of WBASN

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Conclusion(3/3) Simulation results of In-Body Communication show that o Path loss increases with increase in Frequency and Distance between Sensor Nodes o Path loss is greater for implantable sensors than for On-Body sensors

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List Of Publications Nadir Ali Khan, Jaffar Kulachi, Umair Rafiq, Ayesha Bibi, Zahoor Ali Khan, Nadeem Javaid, Ubiquitous Healthcare in Wireless Body Area Networks, 11th IEEE International Conference on Ubiquitous Computing and Communications (IUCC-2012), Liverpool, UK, 25-27 June 2012. Sarim Hayat, Abida Shareef, Anzar Mahmood, Zahoor Ali Khan, Safdar Hussain Bouk, Nadeem Javaid, Energy Efficient MAC Protocols in Wireless Body Area Sensor Networks, 14th IEEE International Conference on High Performance Computing and Communications (HPCC-2012), 25-27 June, Liverpool, UK, 2012.