1 / 23

Energy-Efficient, Collision-Free Medium Access Control for Wireless Sensor Networks

Energy-Efficient, Collision-Free Medium Access Control for Wireless Sensor Networks. Venkatesh Rajendran , Katia Obraczka , J.J. Garcia-Luna- Aceves Wireless Networks 2006 JY Hong 2008. 10. 30. Contents. Introduction Related Works TRAMA Protocol Overview Neighbor Protocol

armen
Télécharger la présentation

Energy-Efficient, Collision-Free Medium Access Control for Wireless Sensor Networks

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Energy-Efficient, Collision-Free Medium Access Control for Wireless Sensor Networks VenkateshRajendran, KatiaObraczka, J.J. Garcia-Luna-Aceves Wireless Networks 2006 JY Hong 2008. 10. 30

  2. Contents • Introduction • Related Works • TRAMA • Protocol Overview • Neighbor Protocol • Schedule Exchange Protocol • Adaptive Election Algorithm • Simulation Results • Conclusion TRAMA

  3. Introduction • Wireless Sensor Network (WSN) • Large ensembles of interconnected nodes • Self-organize into a multi-hop wireless network • The scheduling of transmissions among nodes is major challenge • Prolongs the battery life of each node • Self adaptive to changes in traffic, node state, connectivity TRAMA

  4. Related Works - 1 • Research Categories of MAC • Contention-based • DCF 802.11b (Distributed Coordination Function) • PAMAS (Power Aware Multi Access Protocol with Signaling for ad hoc networks) • S-MAC (Sensor MAC) • Schedule-based, Contention-free • TDMA, FDMA, CDMA • NAMA (Node Activation Multiple Access) TRAMA

  5. Related Works - 2 • S-MAC : Basic Mechanism TRAMA

  6. TRafficAdaptive Multiple Access • TRAMA Characteristics • Energy-Efficient • No collision, No idle listening, No idle sender • Schedule-based • Fair • Transmitter-Election Algorithm • Identify of nodes one and two hop away • Traffic information • Adaptive scheduling TRAMA

  7. Protocol Overview • Three components of TRAMA • Neighbor Protocol (NP) • Gather 2-hop neighborhood information • Schedule Exchange Protocol (SEP) • Gather 1-hop traffic information for Scheduling • Adaptive Election Algorithm (AEA) • Select transmitters TRAMA

  8. Protocol Overview • Access mode • Random Access • Node can join the network • All nodes must be in transmit or receive state  Collision • Significant role in energy consumption • Scheduled Access • Collision-free data exchange and schedule propagation Time slot Organization TRAMA

  9. NP • NP • Gather neighborhood information by exchanging small signaling packets in random access period TRAMA

  10. SEP - 1 • Transmission slots • Collision-free data exchange and schedule propagation • SEP • Traffic-based information (Schedules) with neighbors • Traffic coming from a node • The set of receiver for the traffic originating at the node • A node has to announce its schedule using SEP before starting actual transmissions TRAMA

  11. SEP - 2 • Schedule packet format TRAMA

  12. SEP - 3 Schedule packet of node u (if winning slot are 2, 10, 20, 30, 35, 50, 58, 60) • Example u 14 7 2 7 14 15 2 7 14 15 2 7 14 15 2 7 14 15 …….. 2 30 2 10 20 15 Changeover Slot Schedule packet of node 14 (if winning slot are 5, 15, 38, 42) 2 7 14 15 60 u u u u 15 38 5 42 TRAMA

  13. AEA - 1 • Original NCR algorithm • Contending set • All nodes that are in two-hop neighborhood • No sleep state, not adaptive with traffic • TRAMA’s AEA • Possible state of a node • TX(Transmit), RX(Receive), SL(Sleep) TRAMA

  14. AEA - 2 • U is a TX state • Highest priority among its contending set • U has data to send • U is a RX state • Intended receiver of the current transmitter • By consulting the schedule sent out by the selected transmitter • U is a SL state • No transmitter, No intended receiver • Each node executes AEA to decide its current state • Current node priorities in two-hop neighborhood • Based on the announced schedules form one-hop neighbors TRAMA

  15. AEA - 3 • When a node becomes an Absolute Winner for a particular timeslot and has announced a non-zero bitmap for this slot, it know that no other node in its two-hop neighborhood will be transmitting in this slot Absolute Winner Intended Receiver TRAMA

  16. AEA - 4 • To avoid wasting slots when the Winner has no data to send • Possible Transmitter Set in the one-hop neighborhood • Highest priority in two-hop neighbor  No collision • PTX(u) Absolute Winner TRAMA

  17. Simulation Parameters • Simulation platform • QUALNET • 500m X 500m area • 50 nodes are uniformly distributed • 6 one-hop neighbors on average • 17 two-hop neighbors on average • Node traffic • Statistically generated based on a exponentially distributed inter-arrival time TRAMA

  18. Simulation Results - 1 Percentage received TRAMA

  19. Simulation Results - 2 Average Delay TRAMA

  20. Simulation Results - 3 Percentage Sleep time TRAMA

  21. Conclusion • TRAMA achieves • Energy-savings comparable to S-MAC • Delivery guarantees comparable to NAMA • TRAMA Limitations • Complex election algorithm and data structure • Overhead due to explicit schedule propagation • Higher Queueingdelay  Long delay • TRAMA has higher delay • It Suited for • Not delay sensitive • High delivery guarantees • Energy efficiency WSAN : Research Challenges

  22. Questions or Comments WSAN : Research Challenges

  23. Appendix - Alternate Winner Absolute Winner Alternate Winner TRAMA

More Related