Range of IEEE802.11 node.

[Mukul Shukla]

I have modified the "MobileManetRoutingHost" to use IEEE 802.11b instead of IEEE 802.11g by replacing:

wlan: Ieee80211gNicAdhoc {
....
....

}

by

wlan: ieee80211NicAdhoc {

...
...

}

in MobileManetRoutingHost.ned

Now my question is that by just making this change am I using IEEE802.11b instead of IEEE 802.11g. I also want to no what will be the transmission range of the nodes as per the wireless NIC parameters of the Net80211_aodv examples?

Thanking you.

Mukul

[Mukul Shukla]

There was the problem in Net80211_aodv example of the INETMANET that the area was large and there were fewer hosts. The affect was that the routing packets could not be reached to the destination.

 I am using "Ieee80211NicAdhoc" (IEEE 802.11b) as a wlan protocol instead of Ieee80211gNicAdhoc. My question is what is the transmission range of the IEEE 802.11b protocol and where is it modeled in the INETMANET package?

Thanking you.

Mukul

[Alfonso Ariza]

 

in the file src/linklayer/radio/PathLossReceptionModel.cc

Method PathLossReceptionModel::calculateReceivedPower

[Mukul Shukla]

Thanks a lot for the reply. I have gone through the method:
 PathLossReceptionModel::calculateReceivedPower in src/linklayer/radio/PathLossReceptionModel.cc.

Wavelength is calculated as speedofLight/carrierFrequency. But I could not understand the power calculated in the return statement:

 "return(pSend * waveLength * waveLength / (16 * M_PI * M_PI * pow(distance, pathLossAlpha)))".

Can you please explain me how to calculate the power and from it the distance of the transmission in theory and in the code above?

Thanking you once again.

Mukul

[Alfonso Ariza]

You can find the equation in

http://en.wikipedia.org/wiki/Friis_transmission_equation

 

The antenna gain is 1 in the simulator

[Mukul Shukla]

Thank you so much for the help. Yes, the equation calculates the Received Power with the Free Space Model. But I could not understand one thing. How is the 'transmission range' calculated in the Ieee802b model? I mean the function returns the received power calculated and uses the distance, but how to calculate the transmission range? Or what is the realistic transmission range used in the standard Ieee 802.11 model?

Thanking you once again.

Mukul

[Alfonso Ariza]

In the ini file is defined the transmission power and the sensitivity. If the received power is bigger that the sensitivity the packet is received, in other case is only noise, these two parameters (and the propagation model) determine the maximum transmission distance

**.wlan.radio.transmitterPower=2.0mW
**.wlan.radio.sensitivity=-85dBm    

[Mukul Shukla]

Dear Alfonso,

Thanks for the prompt reply. Now it is making some sense to me. I want to know whether this is the criteria for calculating the transmission distance in the real life? Or in real life the situation is different?

Thanks.

Mukul

[Mukul Shukla]

And again, I am not able to understand the use of variable "pathLossAlpha".

[Alfonso Ariza]

this variable is the "speed" of the attenuation.

[Alfonso Ariza]

The free space model is not very realistic, but, due to the maximum transmission distance is very short, it’s enough. In real life (and simulations) the standard wifi maximum transmission is about 250 meters,

 

 

[Alfonso Ariza]

You can find more realistic models in this thesis

http://wsl.stanford.edu/Publications/Andrea/thesis.pdf

[Mukul Shukla]

I was trying to calculate the maximum transmission range with the parameters available:

Power Transmitted = Pt = 2mW = 3dBm (given from the ini file)
Power Received = Pr = (I have taken it to be the sensitivity value = -90 dBm (is it right?)
Gt, Gr are taken to be 1 in the simulation.

Now I have the following doubts:
1.How can I calculate  the value of Wavelength. It has been calculated in the method PathLossReceptionModel::calculateReceivedPower. The wavelength is calculated as speed of light / carrier frequency. What is the value of carrier frequency and where is it defined?
2. Will the maximum distance comes out to be approx 250m if I calculate it by above values?
3. Point me if I am going wrong?

Thanking you.

Mukul

[Alfonso Ariza]

The frequency

*.channelcontrol.carrierFrequency = 2.4GHz

 

you can find a expresion in

http://en.wikipedia.org/wiki/Free-space_path_loss

that help to compute the maximun distance

 

Atenuation(dB) = 20 log( d ) + 20 log ( f ) + 32.45

 

d in Km and f in Mhz

[Mukul Shukla]

The main problem is to find out attenuation (in db). As from the formula given, I should know frequency (that is known) and the attenuation (in db), only then one can calculate 'd' the distance. I am confused regarding the attenuation. How to set this?

Thanking you.

Mukul

[Alfonso Ariza]

I can't understand the problem.

The packet is received if

(Transmission power in dBm)  – (Attenuation in dB) > (sensibility in dBm)

[Shezi A]

Dear Alfonso, 

Could you please share some reference for this?

I have mostly seen 802.11g being described as having at most 50m range.. 

Here is one such reference:

http://my.safaribooksonline.com/book/certification/networkplus/9780768690347/wireless-networking/ch07lev1sec4

Kind regards,

Shezi

[Alfonso Ariza Quintana]

Most of ns2 simulation set the distance to 250 meters, I usually set the distance to the range 100-120 meters

 

And the distance that is in your reference is indoor, that it is a lots shorter than outdoor

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[N.omar]

Hello all 

I assigned the following parameters in the configration file 

*.channelControl.carrierFrequency = 2442MHz # old value 2.4GHz

*.channelControl.pMax = 20mW

_

_

_

**.wlan.radio.transmitterPower = 20mW

**.wlan.radio.sensitivity = -75.4dBm 

,  SO i got range = 257m

by using the formla 

So are my calculation correct ???? plz i need to know 

[Alfonso Ariza Quintana]

http://www.radio-electronics.com/info/propagation/path-loss/free-space-formula-equation.php

 

De: omn...@googlegroups.com [mailto:omn...@googlegroups.com] En nombre de N.omar
Enviado el: martes, 21 de mayo de 2013 20:34
Para: omn...@googlegroups.com
Asunto: [Omnetpp-l] Re: Range of IEEE802.11 node.

 

Hello all 

I assigned the following parameters in the configration file 

 

*.channelControl.carrierFrequency = 2442MHz # old value 2.4GHz

*.channelControl.pMax = 20mW

_

_

_

**.wlan.radio.transmitterPower = 20mW

**.wlan.radio.sensitivity = -75.4dBm 

 

,  SO i got range = 257m

 

by using the formla 

 

So are my calculation correct ???? plz i need to know 

--

[N.omar]

.Thank  you mr.Alfonso

but  what is the benifit from this website  ?! 

since I am using adhoc network 

?what i want to know is does Using the previous formula is correct or not

and how I can make sure about the transmission range  value ?! 

Thank