NAME: NASIRAHMAD

PROGRAM: B.S TELECOM

SEMESTER: 7TH

REG#: SU/08-01-03028

PRESENTED TO: ENGR. GUL ZAMEEN KHAN

DATE: 10-03-2012

UNIVERSITY: SARHAD UNIVERSITY

A Survey on sensor network

Abstract• Development in wireless communication and

electronics has enabled the development of low cost sensor network.

• Application area is wide, use in domestic, industry, military, agriculture, e.t.c

Introduction

• Nodes (tiny sensors)= match box, it contain sensing unit, processing unit, communication components, power unit.

• Communicate each other in short distance make a network called sensor network.

• ISM (industrial, scientific, medical) band is used for communication, 915 MHz, 2.4 GHz

• ISM BAND(6.76MHz -246GHz)• A sensor network is composed of large number of nodes

densely deployed in the field.• Position is not predetermined.

Introduction

• That’s why design of algorithm and protocol for sensor networks must posses self organizing capabilities.

• Collect raw data but communicates information because of processing unit.

SENSOR NETWORKSCOMMUNICATION ARCHITECTURE

• sensor nodes are scattered in the sensing field collect data and route it to sink

• Sink communicate with task manager node via internet or satellite

• Design of sensor network is influenced by some factors

DESIGN FACTORS

• including fault tolerance, scalability, production costs, operating environment, sensor network topology, hardware constraints, transmission media, and power consumption.

Hardware Constraints

THE PHYSICAL LAYER

• The physical layer is responsible for frequency selection, carrier frequency generation, signal detection, modulation, and data encryption.

• Frequency selection 7km bluetooth radio system at 2.4 GHz, 10km infrared free licence 915 MHz.

• Modulation: binary and m-ary modulation

Problems

• The choice of a good modulation scheme iscritical for reliable communication in a sensornetwork. The binary modulation is good at start and

consume less power while m-ary is good scheme for sending multiple bits per cycle it reduce transmit on time but it need complex circuitry which consume more radio power.

• Ultra wide band (UWB) or impulse radio (IR) is used as good base band (carrier) for indoor wireless sensor networks communication.

OPEN RESEARCH ISSUES

• Open research issues range from power-efficient transceiver design to modulation schemes

• Hardware design

THE DATA LINK LAYER

• The MAC protocol in a wireless multi-hop self-organizing sensor network must achieve two goals. The first is the creation of the network infrastructure. The second objective is to fairly and efficiently share Communication resources between sensor nodes.

• Since thousands of sensor nodes are densely scattered in a sensor field, the MAC scheme must establish communication links for data transfer.

• This forms the basic infrastructure needed for wireless communication hop by hop and gives the sensor network self-organizing ability.

Reasons Existing MAC ProtocolsCannot Be Used

why the existing MAC cannot be adopted into the sensor network scenario ?

Let in an infrastructure based (cellular system) a mobile is a single hop away one hop from base station. Here MAC provide QOS and bandwidth efficiency and power consumption is secondary importance but in sensor n/w power consumption is important and there is no base station so it makes synchronization a difficult task in sensor n/w.

So what is good

• Bluetooth and the mobile ad hoc network (MANET) are probably the closest peers to sensor networks.

• Bluetooth is infrastructure less short range wireless system using star topology

• MANET form infrastructure and maintain it in the face of mobility

• Self-Organizing Medium Access Control for Sensor Networks (SMACS) and the Eavesdrop-And-Register (EAR) Algorithm

• The SMACS protocol achieves network startup and link-layer organization, and the EAR algorithm enables seamless connection of mobile nodes in a sensor network. The EAR protocol attempts to offer continuous service to the mobile nodes under both mobile and stationary conditions.

Hybrid TDMA/FDMA-Based

• a pure FDMA scheme allocates minimum signal bandwidth per node. Despite the fact that a pure TDMA scheme minimizes the transmit-on time,

ERROR CONTROL

• Another important function of the data link layer is the error control of transmission data. Two important modes of error control in communication networks are forward error correction (FEC) and automatic repeat request

(ARQ).• Reliable data communication can be provided either by

increasing the output transmit power (Pout) or the use of suitable FEC.

• FEC is used for controlling errors in data transmission over unreliable and noisy channel

OPEN RESEARCH ISSUES

• MAC for mobile sensor networks• Error control coding schemes• Power-saving modes of operation:

NETWORK LAYER

• special multihop wireless routing protocols between the sensor nodes and the sink node are needed. Traditional ad hoc routing techniques do not usually fit the requirements of the sensor networks due to the reasons explained earlier

• One important function of the network layer is to provide Internetworking with external networks such as other sensor networks, command and control systems and the Internet. In one scenario, the sink nodes can be used as a gateway to other networks.

Protocols• FLOODING (resource blindness)• GOSSIPING (derivation of flooding)• SENSOR PROTOCOLS FOR INFORMATION VIA

NEGOTIATION• SEQUENTIAL ASSIGNMENT ROUTING LOW-

ENERGY ADAPTIVE CLUSTERING HIERARCHY• DIRECTED DIFFUSION• SMALL MINIMUM ENERGY

COMMUNICATION NETWORK

TRANSPORT LAYER

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

THE APPLICATION LAYER

• SENSOR QUERY AND DATA DISSEMINATION PROTOCOL

CONCLUSION

• The flexibility, fault tolerance, high sensing fidelity, low cost, and rapid deployment characteristics of sensor networks create many new and exciting application areas for remote sensing. In the future, this wide range of application areas will make sensor networks an integral part of our lives.

• However, realization of sensor networks needs to satisfy the constraints introduced by factors such as fault tolerance, scalability, cost, hardware, topology change, environment, and power consumption.