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Nov 21, 2013 (3 years and 10 months ago)

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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 NETWORKS

COMMUNICATION 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 is

critical for reliable communication in a sensor

network. 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 Protocols

Cannot 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.