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SELF-ORGANIZING MEDIA ACCESS MECHANISM OF A WIRELESS SENSOR NETWORK

SELF-ORGANIZING MEDIA ACCESS MECHANISM OF A WIRELESS SENSOR NETWORK. AHM QUAMRUZZAMAN. Sensor Networks. Composed of large number of sensor nodes. Nodes are able to communicate in short distance Limited energy Limited storage, processing power Multi-hop topology. Application.

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SELF-ORGANIZING MEDIA ACCESS MECHANISM OF A WIRELESS SENSOR NETWORK

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  1. SELF-ORGANIZING MEDIA ACCESS MECHANISM OF A WIRELESS SENSOR NETWORK AHM QUAMRUZZAMAN

  2. Sensor Networks • Composed of large number of sensor nodes. • Nodes are able to communicate in short distance • Limited energy • Limited storage, processing power • Multi-hop topology

  3. Application • Useful to extract and monitor data • Randomly deployed for military surveillance • Widespread environmental sampling • Health monitoring

  4. Important Issue • Power conservation and management are most important factors • Quality of service and bandwidth efficiency are secondary issue • An improved low-power scalable self-organization protocol will be desirable

  5. Sensor Network Challenges • Major drawback- limited energy • Topology changes very frequently • Hardware design challenge • Scalability • Prone to failure • Broadcast communication • Cost

  6. Sensor Network vs. other Wireless Network • A cellular network • composed of stationary and mobile nodes. • The network has infrastructure • The base station has unlimited power • The base station covers a wide range • Main objective- quality of service with high bandwidth

  7. Sensor Network vs. other Wireless Network • Mobile ad hoc Network (MANET) • Peer-to-peer network • Consists of 10 to 100 nodes • Main objective- quality of service • Energy resource is secondary important

  8. Sensor Network vs. other Wireless Network • Bluetooth technology • Enables wireless link among electronic devices • One master and can support up to seven devices within its network to form a piconet • All nodes are synchronized to master • Low power and low data rate • TDMA protocol

  9. Sensor Network vs. other Wireless Network • Sensor network is different from all of these networks • Main objective- power management • It may have a much larger of nodes • Transmission power and radio range are much less than Bluetooth and MANET • Mobility rates are much slower than MANET

  10. Media Access Control (MAC) • Self-organization capability • Ability of the system to function properly without human assistance • It enable nodes to coordinate among themselves to achieve a large sensing task with little energy usage

  11. Media Access Control (MAC) • Transmission Media: • Optical Media • Infrared • Radio • Channel access is done by two different methods: • Contention based protocol • TDMA based protocol

  12. Media Access Control (MAC) • Nodes power saving technique • Letting the nodes sleep whenever possible • Nodes go into the idle mode when it has nothing to do • Idle node consumes the same energy as the active node • Proper choice of protocols will be able to turn off and on the radio when necessary

  13. Media Access Control (MAC) • Scalability of nodes • Error control • Forward Error Correction (FEC) • Automatic Repeat Request (ARQ)

  14. Traditional MAC Protocols • CSMA Scheme • MACA and MACAW • CSMA with collision detection and Slotted ALOHA • IEEE 802.11 • Bluetooth based protocol

  15. Current Survey of MAC Protocol for Wireless Sensor Network • Sohrabi and Pottie proposed S (Stationary)-MAC • TDMA based protocol • Power conservation achieved by using random wakeup schedule and by turning off the radio during idle times. • Limitation: low bandwidth utilization

  16. Current Survey of MAC Protocol for Wireless Sensor Network • Adaptive transmission control (ARC) proposed by Woo and Culler • In ARC mechanism, node periodically attempts to inject the packet. • If the packet is not injected successfully, it signals that the road is jammed. • So the node can reduce the transmission rate.

  17. Current Survey of MAC Protocol for Wireless Sensor Network • DE-MAC, distributed energy-aware protocol • treats the critical nodes differently • Criticality depends on the relative energy levels within the neighboring nodes. • Protocol performs a local election process to select the weaker nodes and make them sleep. • Low energy nodes sleep more than high energy nodes and increases energy saving.

  18. Current Survey of MAC Protocol for Wireless Sensor Network • Sensor MAC protocol proposed by Heidemann and Estrin • Nodes go into periodic sleep. • During the sleep, nodes turn off the radio • Also sets the nodes sleep during the transmission of other nodes • To prevent collision and overhearing, it uses 802.11 contention based mechanism (RTS/CTS)

  19. Comparative Performance

  20. Conclusion • Many important research questions remain regarding prolong lifetime of nodes • Current error detection control scheme are not enough • Future research must satisfy fault tolerance, scalability, cost, hardware, topology change and power consumption.

  21. THANK YOU

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