1. Critical Area Attention in Traffic Aware Dynamic Node Scheduling for Low Power Sensor Network Proceeding of the 2005 IEEE Wireless Communications and Networking Conference Reporter : Chia-Nung Wang Reporter : Chia-Nung Wang

2. 2 Outline Introductions Introductions The protocols of SMAC and DMD The protocols of SMAC and DMD DNSM DNSM TADNS TADNS Simulations Simulations Conclusions Conclusions

3. 3 Introductions The main idea of sensor network is long time functionality. The main idea of sensor network is long time functionality. For many applications, full coverage and power saving is very important. For many applications, full coverage and power saving is very important. FDMA and CDMA are not suitable for sensor network. FDMA and CDMA are not suitable for sensor network. Use local traffic information to optimize power consumption. Use local traffic information to optimize power consumption.

4. 4 Introductions (cont.) Current sensor network protocol is Current sensor network protocol is SMAC( Sensor Media Access Control ) and SMAC( Sensor Media Access Control ) and DMD( Distributed node schedule management DMD( Distributed node schedule management includes a Mediation Device ) includes a Mediation Device ) This paper will descript TADNS, that is DNSM (Distributed node schedule management ) This paper will descript TADNS, that is DNSM (Distributed node schedule management ) including local traffic information including local traffic information

5. 5 SMAC Utilize virtual clustering to provide good scalability. Utilize virtual clustering to provide good scalability. If no one wants to talk to the node, it will go to sleep until the next listen period. If no one wants to talk to the node, it will go to sleep until the next listen period. Each node shares its listening schedule with neighbors in order to form a virtual cluster. Each node shares its listening schedule with neighbors in order to form a virtual cluster. Nodes on the board of different clusters must support more than one schedule. Nodes on the board of different clusters must support more than one schedule.

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7. 7 SMAC (cont.) Clusters are resynchronized at the beginning of scheduled listening interval (SYNC packet)

8. 8 DMD A new task called mediation device ( MD ). A new task called mediation device ( MD ). The node in charge acts as a mediator between other nearby nodes. The node in charge acts as a mediator between other nearby nodes. All the nodes periodically enter MD mode and listen to other sensor ’ s queries. All the nodes periodically enter MD mode and listen to other sensor ’ s queries. Each node wake up at a random time, and transmits a query packet to announce its next scheduled wake up time that is record by MD. Each node wake up at a random time, and transmits a query packet to announce its next scheduled wake up time that is record by MD.

9. 9 DMD (cont.)

10. 10 DNSM Combine the benefits of SMAC and DMD. Combine the benefits of SMAC and DMD. Construct on a scheduled listening scheme. Construct on a scheduled listening scheme. Data transmission in DNSM use a collision avoidance. Data transmission in DNSM use a collision avoidance. Each node establishes a database of neighbor node ’ s schedules. Each node establishes a database of neighbor node ’ s schedules. In this protocol, the MD role has been assigned to all of nodes. In this protocol, the MD role has been assigned to all of nodes.

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12. 12 TADNS There are three main design parameters in the DNSM. There are three main design parameters in the DNSM. Dynamic selection of DNSM parameters is the main idea of traffic aware scheduling. Dynamic selection of DNSM parameters is the main idea of traffic aware scheduling. The data transformation is kept the same as DNSM. The data transformation is kept the same as DNSM. In the listening interval, each node may receive a SU ( schedule update ). In the listening interval, each node may receive a SU ( schedule update ).

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14. 14 Simulation Symmetric traffic case: Symmetric traffic case: Asymmetric traffic case: Asymmetric traffic case:

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19. 19 Conclusions A new wireless sensor network MAC layer was presented and compares with SMAC and 802.11. A new wireless sensor network MAC layer was presented and compares with SMAC and 802.11. The new protocol inherits certain properties of MD and SMAC. The new protocol inherits certain properties of MD and SMAC. Low power consumption and collision avoidance are the main advantage of DNSM. Low power consumption and collision avoidance are the main advantage of DNSM. TADNS protocol reduce power when the traffic node in the network is high. TADNS protocol reduce power when the traffic node in the network is high.