A Survey on Sensor Networks

1. A Survey on Sensor Networks Hussein Alzoubi Hussein_alzoubi@hotmail.com Rami Alnamneh Ramir11@yahoo.com

2. Outline • Introduction • Communication architecture • Protocol stack • Conclusion

3. Introduction • Sensor Networks…low-cost, rapid deployment, self-organizing, and fault tolerance. • Application areas: heath, military, and home. • Large number of sensor nodes that are densely deployed. • Nodes use their processing abilities to locally carry out simple computations and transmit the required and partially processed data. • Ad hoc networks are not suitable for the sensor networks because of their unique features and application requirements.

4. Communication Architecture Internet and Satellite Sink C D A E B Task manager node Sensor nodes Sensor field User

5. Design Factors • Fault Tolerancethe ability to sustain sensor network functionalities without any interruption due to sensor node failures because of lack of power, physical damage, or environmental interference. • Scalabilitythe density of sensor nodes can range from few sensor nodes to few hundred sensor nodes in a region. • Production Coststhe cost of sensor node should be much less than $1 in order for the sensor network to be feasible

6. Continue.. Design Factors Hardware Constraints Location finding system Mobilizer Sensing Unit Processing Unit Processor Transceiver Sensor ADC Storage Power Unit Power generator

7. Continue.. Design Factors • Sensor Network Topology- Predeployment and deployment phase- Post-deployment phase- Redeployment of additional nodes phase • Environmentcan work in different environments. • Transmission Medialinks between nodes can be formed by radio, infrared, or optical media. • Power Consumptionbattery lifetimedesign of power-aware protocols and algorithmsPower consumption: sensing, communication, and data processing

8. Protocol Stack Task management plane Application layer Mobility management plane Transport layer Power management plane Network layer Data link layer Physical layer

9. The Physical Layer • Frequency selection. • Carrier frequency generation. • Signal detection. • ModulationBinary and M-ary modulation schemesthe binary modulation scheme is more energy-efficient • Low transmission power and simple transceiver circuitry make Ultra wideband (UWB) an attractive candidate.

10. The Data Link Layer • Multiplexing of data streams. • Data frame detection. • Medium access and error control. • Ensures reliable point-to-point and point-to-multipoint connections in a communication network.

11. Continue.. The Data Link Layer Medium Access Control • Must achieve two goals- the creation of the network infrastructure- share communication resources between sensor nodes fairly and efficiently. • Can’t be adopted into sensor networks, because- there is no central controlling agent like the base station.- power efficiency directly influences network lifetime in sensor network.

12. Continue.. The Data Link Layer Some of the proposed MAC protocols

13. Continue.. The Data Link Layer Power saving modes of operation Turning the transceiver off during idling may not always be efficient due to energy spent in turning it back on each time. Error control Two modes of error control:- Forward Error Correction, decoding complexities.-Automatic Repeat Request (ARQ), additional retransmission energy cost and overhead. Best solutions: simple error control codes with low-complexity encoding and decoding

14. Sink α 3=2 α 1=1 E (PA=1) α 4=2 A (PA=2) α 2=1 D (PA=3) α 6=2 B (PA=2) α 5=2 α 7=1 α 8=2 α F (PA=4) α 9=2 T C (PA=2) Network Layer Route 1: Sink-A-B-T, total PA=4, total α = 3 Route 2: Sink-A-B-C-T, total PA=6, total α = 6 Route 3: Sink-D-T, total PA=3, total α = 4 Route 4: Sink-E-F-T, total PA=5, total α = 6 Task: energy efficient routes • Approaches: • Minimum PA route: route 4 • Minimum Energy (ME) route: route 1 • Minimum hop (MH) route: route 3 • Maximum minimum PA node route: route 3

15. Continue.. Network Layer Data Aggregation, data fusion C B A E D F G Sink

16. Continue.. Network Layer Routing techniques • Floodingeach node receiving a data or management packet repeats it by broadcasting. • Gossipingsend the incoming packets to a randomly selected neighbor.

17. ADV REQ DATA Step 1 Step 2 Step 3 ADV REQ DATA Step 4 Step 5 Step 6 Continue.. Network Layer Sensor Protocols for Information via Negotiation (SPIN)

18. Continue.. Network Layer Sequential Assignment Routing (SAR)Creates multiple trees where the root of each tree is a one-hop neighbor from the sink. Low-Energy Adaptive Clustering Hierarchy (LEACH)Forms clusters to minimize energy dissipation. Directed diffusionSets up gradients for data to flow from source to sink during interest dissemination.

19. Transport Layer Transport layer protocols are still unexplored: they may be purely UDP-type protocols, because each sensor node has limited memory and power.

20. The Application Layer • Sensor Management Protocol (SMP)makes the hardware and software of the lower layers transparent to the sensor network management applications. System administrators interact with sensor networks using SMP. • Task Assignment And Data Advertisement Protocol (TADAP)provides the user software with efficient interfaces for interest dissemination. • Sensor Query and Data Dissemination Protocol (SQDDP)provides user applications with interfaces to issue queries, respond to queries and collect incoming replies.

21. Conclusion The flexibility, fault tolerance, high sensing fidelity, low cost, and rapid deployment characteristics ofsensor networks create new and exciting application areas for remote sensing.

22. Questions? Thank you!