power consumption by means of wi fi

MEASUREMENT OF POWER CONSUMPTION IN DIFFERENT

PROPAGATION MODELS USING Wi-Fi - a case study

Wi-Fi Case 1 study of quasi-open

propagation modelConclusion Future work Bibliography

Out l ine

What is Wi-Fi Why Wi-Fi Brief history of Wi-Fi Various transmission impairments Channel modeling Log-distance path loss model Disadvantages Case study 1- quasi-open propagation environment Matlab program for pathloss graph Conclusion Future work Bibliography

CONTENTS

• Short name for wireless fidelity and is meant to be used generically when referring to any type of IEEE 802.11 network. Whether 802.11b, 802.11a, 802.11g etc.

• Wi-Fi is a wireless technology that uses radio frequency (ISM Band, 2.4/5 GHz) to transmit data through data through air.

What is Wi-Fi ?

Setup cost - Reduced cabling required Flexibility - Quick and easy to setup in

temperature and permanent space

Scalable - Can be expanded with growth

Freedom - You can work from any location that can get a signal

Why Wi-Fi ?

Lower total cost of ownership – Because of affordability and low installation cost.

Additionally- Mobile users can access the

corporate network from any public hotspot using VPN.

Why Wi-Fi ? (contd.)

IEEE established the 802.11 group in 1990. Specifications for standard ratified in 1997.

Initial speed were 1 and 2 Mbps. IEEE modified the standard in 1999 to include

802.11 a and b. 802.11 g was added in 2003. 802.11 b equipment first available, then a,

followed by g. IEEE create standard but wireless Ethernet

compatibility alliance certifies products.

Brief History

Attenuation: The strength of a signal falls off with distance over any transmission medium.

Free space loss: A receiving antenna will

receive less signal power the farther it is from the transmitting antenna. This form of attenuation is known as free space loss.

Fading: Fading refers to the time variation of received signal power caused by changes in the transmission medium or path.

VARIOUS TRANSMISSION IMPAIRMENTS

Multipath: Multipath is caused by the following propagation mechanisms: - Reflection Diffraction Scattering Refraction Noise Atmospheric absorption.

Various transmission impairments (contd.)

A channel model is useful in determining the mechanisms by which propagation in the indoor environment occurs, which in turn is useful in the development of a communication system.

Indoor channels are highly dependent upon the placement of walls and partitions within the building. As placement of these walls and partitions dictates the signal path inside a building.

Channel Modeling

In both indoor and outdoor environments the average large-scale path loss for an arbitrary Transmitter-Receiver (T-R) separation is expressed as a function of distance by using a path loss exponent, n.

The average path loss PL(d) for a transmitter and receiver with separation d is:

PL(d)=PL(d0)+10•n•log10(d/d0)

Log-distance Path Loss Model

Wireless LAN is typically deployed as an extension of an existing wired network as shown below

Wireless LAN Topology

• Planning – Depending on the goal • Security - Greater exposure to risks • Range – Affected by various media• Travels best through open space • Reduced by water, walls, glass etc.

Disadvantages

Quasi-Open Propagation Environment

DISTANCE (M)

TRANSMITTER SIGNAL STRENGTH (dB)

RECEIVER SIGNAL STRENGTH (dBm)

POWER CONSUMTION (watt)

3 -11 -30 13.16 -17 -419 -21 -4912 -18 -4315 -21 -5118 -22 -54 12.421 -17 -6624 -18 -6327 -16 -66

OBSERVATION TABLE

DISTANCE (M)

TRANSMITTER SIGNAL STRENGTH (dB)



30 -18 -6133 -18 -6936 -22 -80 12.639 -25 -7542 -23 -7845 -26 -8148 -25 -7651 -29 -7554 -17 -72 12.2

OBSERVATION TABLE (contd.)

DISTANCE (m)

TRANSMITTER SIGNAL STRENGTH (dBm)

RECEIVER SIGNAL STRENGTH (dm)


57 -15 -6660 -23 -7763 -21 -7066 -27 -8269 -17 -6772 -12 -73 12.475 -17 -7478 -16 -5781 -15 -69


DISTANCE (M)

TRANSMITTER SIGNAL STRENGTH (dBm)



84 -15 -6787 -15 -7590 -16 -76 12.393 -16 -7596 -15 -7999 -16 -73102 -34 -87105 -22 -86108 -26 -83


y=[19 24 28 25 30 32 49 45 50 43 51 58 50 55 55 51 46 55 51 54 49 55 50 61 57 43 54 52 60 60 59 64 57 53 64 57];x=1:1:36;lx=log10(x);p=polyfit(lx,y,1);figure(1)plot(lx,y,'o');xlabel('log10(d/d0)');ylabel('pathloss(dBm)');

MATLAB PROGRAM FOR PATHLOSS GRAPH

Plot for finding out pathloss coefficient(n)

So far , we have studied one environment in this semester (i.e.- Quasi-open environment).Few more environments are needed to be studied in order to draw a conclusion about the energy efficient propagation model but we are able to find out only the path-loss coefficient(n) in the present semester.

CONCLUSION

In the next semester, we shall be concluding with our rest of the observation readings in some more environments i.e... closed environment; open environment; dense environment.

FUTURE WORK

T H A N KY O UFOR

PAYINGATTENTION

power consumption by means of wi fi

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