Trends in Wireless [Multimedia] Sensor Networks

1. Trends in Wireless [Multimedia] Sensor Networks Mr.M.Balasubramani Asst. Professor CSE Department PSNA CET Faculty seminar 14.02.2015

2. Agenda • Intro.. • Features • Applications-WSN:WMSN • Goals/characteristics of WMSN • Architecture • Challenges/Issues • Components & characteristics of wireless video systems • Factors influencing the design • Application domains • Proposals… • Interesting applications…

3. Introduction Sensor networks VS ad hoc networks: • The number of nodes in a sensor network > the nodes in an ad hoc network. • Sensor nodes are densely deployed. • Sensor nodes are limited in power, computational capacities and memory. • The topology of a sensor network changes frequently. • Sensor nodes mainly use broadcast, most ad hoc networks are based on p2p. • Sensor nodes may not have global ID.

4. Wireless Sensor Networks (WSNs) • Wireless Sensor Networks features • Homogeneous devices • Stationary nodes • Dispersed network • Large network size • Self-organized • All nodes acts as routers • No wired infrastructure • Potential multihop routes

5. Applications of Sensor networks

6. Applications of sensor networks Military applications • Monitoring friendly forces, equipment and ammunition • Investigation/survey of opposing forces and terrain • Battlefield surveillance(observation) • Battle damage assessment • Nuclear, biological and chemical attack detection

7. Applications of sensor networks Environmental applications • Forest fire detection • Biocomplexity mapping of the environment • Flood detection • Precision agriculture

8. Applications of sensor networks Health applications • Tele-monitoring of human physiological data • Tracking and monitoring patients and doctors inside a hospital • Drug administration in hospitals

9. Applications of sensor networks Home and other commercial applications • Home automation and Smart environment • Interactive museums • Managing inventory control • Vehicle tracking and detection • Detecting and monitoring car thefts

10. WSNs - Applications • Applications • Habitat monitoring • Disaster relief • Target tracking • Agriculture

11. What’s so special about WMSNs ? • computation-communication paradigm of traditional WSNs • focused only on reducing energy consumption • WMSNs applications have a second goal, as important as the energy consumption • delivery of application-level quality of service (QoS) • mapping of this requirement to network layer metrics, like latency • This goal has (almost) been ignored in mainstream research efforts on traditional WSNs

12. What’s so special about WMSNs ? • Resource constraints • sensor nodes are battery-, memory- and processing-starving devices • Variable channel capacity • multi-hop nature of WMSNs implies that wireless link capacity depends on the interference level among nodes • Multimedia in-network processing • sensor nodes store rich media (image, video), and must retrieve such media from remote sensor nodes with short latency

13. Wireless Multimedia Architecture

14. Wireless Multimedia Challenges • Adaptive Decoding - Optimizing rich digital media for mobile information devices with limited processing power, limited battery life and varying display sizes • Error Resilience - Delivering rich digital media over wireless networks that have high error rates and low and varying transmission speeds • Network Access - Delivering rich digital media without adversely affecting the delivery of voice and data services • Negotiable QoS for IP multimedia sessions as well as for individual media components

15. Components of a Wireless Video System Input Video Transport + Network Layer Video Encoder Packetizer Channel Encoder Modulator Wireless Channel Output Video Video Decoder Depacketizer Channel Decoder Demodulator Tradeoff: Throughput, Reliability, Delay

16. Characteristics of a Wireless Video System • The capacity of wireless channel is limited by the available bandwidth of the radio spectrum and various types of noise and interference • The wireless channel is the weakest link of multimedia networks – mobility causes fading and error bursts • Resulting transmission errors require error control techniques (such as FEC - forward error control and ARQ – automatic repeat request)

17. The Case for Scalable Video Coding • In emerging wireless applications, multimedia data will be streamed: • over various access networks (GPRS, UMTS, WLANs, etc.) • to a variety of devices (PCs, TVs, PDAs, cellular phones, etc.) • The transmission of multimedia data need to cope with unpredictable bandwidth variations: • due to heterogeneous access technologies of receivers (3G, 802.11a, etc.) or • due to dynamic changes of network conditions (interference, etc.)

18. Factors Influencing Sensor Network Design

19. Factors influencing sensor network design

20. Factors influencing sensor network design • Fault Tolerance • Scalability • Hardware Constrains • Sensor Network Topology • Environment • Transmission Media • Power Consumption

21. Factors influencing sensor network design Fault tolerance • Fault tolerance is the ability to sustain sensor network functionalities without any interruption due to sensor node failures. • The fault tolerance level depends on the application of the sensor networks.

22. Factors influencing sensor network design Scalability • Scalability measures the density of the sensor nodes. • Density = (R) =(N R2)/AR – Radio Transmission Range

23. Factors influencing sensor network design Production costs • The cost of a single node is very important to justify the overall cost of the networks. • The cost of a sensor node is a very challenging issue given the amount of functionalities with a price of much less than a dollar.

24. Factors influencing sensor network design Hardware constraints

25. Factors influencing sensor network design Sensor network topology • Pre-deployment and deployment phase • Post-deployment phase • Re-deployment of additional nodes phase

26. Factors influencing sensor network design Environment • Busy intersections • Interior of a large machinery • Bottom of an ocean • Surface of an ocean during a tornado • Biologically or chemically contaminated field • Battlefield beyond the enemy lines • Home or a large building • Large warehouse • Animals • Fast moving vehicles • Drain or river moving with current.

27. Factors influencing sensor network design Transmission media In a multihop sensor network, communicating nodes are linked by a wireless medium. To enable global operation, the chosen transmission medium must be available worldwide. • Radio • infrared • optical media

28. Factors influencing sensor network design Power Consumption • Sensing • Communication • Data processing

29. proposals … • Cooperative Caching: • multiple sensor nodes share and coordinate cache data to cut communication cost and exploit the aggregate cache space of cooperating sensors • Each sensor node has a moderate local storage capacity associated with it, i.e., a flash memory

30. Proposals… • Organize nodes into groups based on their data request pattern and their mobility pattern • Zone Co-operative, Cluster Cooperative: form clusters of nodes based either in geographical proximity or utilizing widely known node clustering

31. Proposals… • CacheData: intermediate nodes cache the data to serve future requests instead of fetching data from their source • CachePath: mobile nodes cache the data path and use it to redirect future requests to the nearby node which has the data instead of the faraway origin node • the placement of caches

32. The cache discovery protocol (1/2) A sensor node issues a request for a multimedia item • Searches its local cache and if it is found (local cache hit) then the K most recent access timestamps are updated • Otherwise (local cache miss), the request is broadcasted and received by the mediators • These check the 2-hop neighbors of the requesting node whether they cache the datum (proximity hit) • If none of them responds (proximity cache miss), then the request is directed to the Data Center

33. The cache discovery protocol (2/2) When a mediator receives a request, searches its cache • If it deduces that the request can be satisfied by a neighboring node (remote cache hit), forwards the request to the neighboring node with the largest residual energy • If the request can not be satisfied by this mediator node, then it does not forward it recursively to its own mediators, since this will be done by the routing protocol, e.g., AODV • If none of the nodes can help, then requested datum is served by the Data Center (global hit )

34. Application Domains • Home networking: Smart appliances, home security, smart floors, smart buildings • Automotive: Diagnostics, occupant safety, collision avoidance • Industrial automation: Factory automation, hazardous material control • Traffic management: Flow monitoring, collision avoidance • Security: Building/office security, equipment tagging, homeland security • Environmental monitoring: Habitat monitoring, seismic activity, local/global environmental trends, agricultural

35. Some Interesting Applications • The ring sensor • Monitors the physiological status of the wearer and transmits the information to the medical professional over the Internet • Nose-on-a-chip • It is a MEMS-based sensor • It can detect 400 species of gases and transmit a signal indicating the level to a central control station

36. A 16mm computer chip armored in a stainless steel Can Up-to-date information can travel with a person or object iButton

37. Caregivers Assistance Do not need to keep a bunch of keys. Only one iButton will do the work Elder Assistance They do not need to enter all their personal information again and again. Only one touch of iButton is sufficient They can enter their ATM card information and PIN with iButton Vending Machine Operation Assistance iButton Applications

38. iBadge - UCLA • Investigate behavior of children/patient • Features: • Speech recording / replaying • Position detection • Direction detection / estimation(compass) • Weather data: Temperature, Humidity, Pressure, Light

39. iBadge - UCLA

40. Thank you for your attention! Any questions?