SENSOR NETWORKS BY Umesh Shah Mayuresh Patil G P Reddy GUIDES Prof U.B.Desai Prof S.N.Merchant

Outline Of Presentation Introduction to Sensor Networks:Umesh Overview of protocols: G P Reddy Localization: Mayuresh Work done & future plans : Umesh

Outline Of My Presentation Introduction to Sensor Networks. Characteristics & features. Applications. Communication protocols & issues. Physical layer for sensor networks.

What is sensor network ? Large number of nodes randomly deployed. Node localizes itelf & collects data. Nodes collaborate & send the data to base station/sink. Sink communicates with task manager.

Typical sensor network

Features of sensor networks Sensor nodes are very small in size, limited in power, computational capacities, and memory. Sensor network’s topology changes very frequently. Nodes may be mobile. Sensor nodes use broadcast communication paradigm in general.

Features (Contd…) Sensor nodes are very prone to failures. Nodes don’t have global identification. Nodes are large in number & densely deployed.

Applications Habitat monitoring. Climate monitoring. Defence applications: battle field surveillance, treaty monitoring, missile hunting. Warehouse inventory tracking. Vehicle tracking and detection. Monitoring dangerous areas.

Applications(cont…) Transportation. Health care. Disaster recovery. Warfare. Security.

Applications(cont…) Space exploration. Patient monitoring. Robot control and guidance in automatic manufacturing environments.

Typical application

Design factors Scalability Fault Tolerance Node Hardware Energy/Power Consumption Localization & Network Topology Cost Environment & medium

Limitations Energy Computation Communication

Energy/power consumption Battery lifetime/system life time Design of power-aware protocols and algorithms Node originator & router Power consumption: sensing, communication, and data processing

Energy consumption(cont..) Communication v/s processing Multihop network Sleeping node Data aggregation

Localization & Network Topology Large no of nodes close to one other. Node should localize itself &get into network. Creating & maintaining routing information. Additional nodes & mobile nodes.

Routing protocol design targets They must be power efficient. It must be reliable. Delays must be low Power emanation must be low.

Communication protocols Current architecture cant be used as :  Large number of nodes  Nodes are simpler & less complex  Nodes fail frequently  Nodes small in size &power  Header may be too long  Acknowledgement packet energy inefficient

Communication protocol New architecture should : Combine power and routing awareness Integrate data with networking protocols Communicate power efficiently through the wireless medium Share tasks among neighbors

PROTOCOL STACK Application layer Transport layer Network layer Data link layer Physical layer Power management plane Mobility management plane Task management plane

Protocol stack (cont..) Physical layer : simple & robust sensing, modulation, transmission, and receiving techniques MAC Protocol :must be power aware and able to minimize collision Network layer : routing the data supplied by the transport layer application layer : to meet user requirements

Management planes monitor the power, movement, and task distribution among the sensor nodes The power management plane manages how sensor node uses its power The mobility management plane detects and registers the movement of sensor nodes The task management plane balances and schedules the sensing tasks

Energy trade-offs Energy trade-offs in : MAC Protocols. Routing protocol.

PHYSICAL LAYER

Responsibilities Frequency selection. Carrier frequency generation. Signal detection. Modulation. Channel coding/decoding. Data encryption.

Sensor node Sensor should : Sense, process & transmit the data in most energy efficient way. Be of very small size. Use very small power. Extract power from the environment. Work unattended for long time.

Sensor node design Following points should be note : Integrated ckts strictly designed for sensor node. Node not a black box. Application specific processors. Low data rate & redundancy should be exploited. Short data packets and transmission distances

Sensor node design(cont…) Low duty cycle radio electronics. Startup time & energy. Protocols must be designed considering Energy,impact on hardware.

TYPICAL NODE

Typical node(cont…)

Radio Avg power consumption depends upon: Average number of times per second the transmitter/receiver is used. Power consumption of the Tx/Rx operation. ON time. Startup time. MAC protocol used. Modulation scheme used.

Radio(cont…) For energy efficiency should note: Startup time. Startup energy. Active transmit time. Packet size.

Modulation schemes Binary modulation schemes. M-ARY modulation schemes. Compare performance on basis of complexity, data rate, power consumption, transmit on time. Startup power dominant conditions, the binary modulation scheme is more energy-efficient than M-ary scheme.

Power modes Perodic sleep mode for node. Other subsystems can also be turned off when not in use. Subsystems:Processor,Sensor & ADC, Radio. Latency & Energy overhead. State selection policy.

Research issues Design of Sensor node. Modulation schemes. Hardware design. Channel Coding. Strategies to overcome signal propagation effect.

Summary Physical layer research is driven by power aware modulation and hardware design rather than targeting high data rates Adaptive transmit power,dynamic voltage scaling & ability to go to sleep mode are very important energy efficient techniques. Miniaturization, integration, and customization will be required to achieve this

References A Survey on Sensor Networks,Ian F. Akyildiz, Weilian Su,IEEE communications Magazine August E. Shih et al., “Physical Layer Driven Protocol and Algorithm Design for Energy-Efficient Wireless Sensor Networks,” Proc. ACM MobiCom ’01. A. Woo, and D. Culler, “A Transmission Control Scheme for Media Access in Sensor Networks,” Proc. ACM MobiCom ’01.

Thanks ….