How to change transmission power of wifi in ns3

rashad kasim

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Nov 27, 2015, 7:21:36 AM11/27/15

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Hi all,
I am trying to use wifi for longer range communication and as a part of it, I want to increase its transmission power.
I used below part of code
YansWifiPhyHelper wifiInternetPhy = YansWifiPhyHelper::Default ();
wifiInternetPhy.Set ("TxPowerStart", DoubleValue(1600.0206));
wifiInternetPhy.Set ("TxPowerEnd", DoubleValue(160.0206));
wifiInternetPhy.Set ("TxPowerLevels", UintegerValue(1));
wifiInternetPhy.Set ("TxGain", DoubleValue(15) );
wifiInternetPhy.Set ("RxGain", DoubleValue (5) );

But still the radiation range is still the same. Am I making any mistake? Is there any problem if I use default while object creation and then assign other values like I have done?

Regards,
RK

rashad kasim

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Nov 27, 2015, 7:30:53 AM11/27/15

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It would also be great if someone could give me pointer how I can use Wimax in mesh mode.

Regards,
RK

Konstantinos

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Nov 27, 2015, 7:47:37 AM11/27/15

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Hi Rashad,

I do not know what sort of wireless system you want to simulate but those Tx Power levels are un-realistic.

The maximum allowable power is usually <40dBm and you have put it 160 and 1600....
See this link http://www.digitalairwireless.com/wireless-blog/t-eirp/wifi-transmit-power-calculations-made-simples.html

Now, in order to have different levels you have to specify how many.

wifiInternetPhy.Set ("TxPowerLevels", UintegerValue(1));

Now, you have only one, so it simply does not change.

If you add more TxPowerLevels, then you can see dynamic range.

Regards,

K.

rashad kasim

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Nov 29, 2015, 5:40:59 PM11/29/15

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Hello Konstantinos,
Thanks for your reply.
Actually I am trying to see what is the maximum distance for which a node in wifi can be placed away from the wifi node. I tried with default of wifiPhyHelper object, and also tried with higher values. But all the corresponding simulation showed same distance without any improvement.
It would be great, if could give any suggestion to check the maximum signal reaching distance.

Regards,
Rashad

Konstantinos

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Nov 30, 2015, 5:24:21 AM11/30/15

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Hi Rashad,

Have you studied the examples already provided by NS-3, e.g. examples/wireless/rate-adaptation-distance.cc ?

Also, the communication range is a well discussed topic in the list. It has also been explained in the training slides regarding wireless and it depends on many parameters.

Please consider reading the documentation.

Regards,

K.

rashad kasim

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Nov 30, 2015, 7:12:14 AM11/30/15

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Hi Konstantinos,
Thanks for your timely reply and also for your valuable time.
I will go through those examples again and try to understand those examples for better insight.
But my question is more on the relationship between power and radiating distance, given all other parameters are kept fixed. Is it possible just by varying these power related parameters?

Regards,
Rashad

Konstantinos

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Nov 30, 2015, 7:25:05 AM11/30/15

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The relationship between power and radiating distance is explained in many books related to wireless communications.

I would recommend studying one of them, e.g. Digital Communications by J. Proakis.

Still when you vary them, you should use 'valid' values. With 1600dBm (~1.0e+157 Watts) you build a death ray, not a wifi transceiver.

rashad kasim

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Nov 30, 2015, 7:34:41 AM11/30/15

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Thanks Konstantinos,
I will have a looks at the book you suggested.
But the value 1600dBm was just some random value. I started with the default value 16dBm, then kept on varying up and down. I could not see any change in the radiating distance. Unfortunately the value was 1600dBm when I took the screenshot. :(

Regards,
Rashad

Konstantinos

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Nov 30, 2015, 7:49:12 AM11/30/15

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How do you define radiating distance because it is the first time I come across such term.

Usually it is communication range or similar term.

rashad kasim

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Nov 30, 2015, 8:14:42 AM11/30/15

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sorry about confusion on the terminology. When I say radiation distance, I mean the communication range. As in the minimum coordinate where the signal power 0mw.

Apologising again for the confusion.

Regards,
Rashad

Konstantinos

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Nov 30, 2015, 5:32:02 PM11/30/15

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I do not think that you will ever see signal power 0mw as you will always receive something, it could be noise. That's why you do not see any difference by changing the Tx signal power

The point is when that signal you receive is comprehensible.
Again, the place to look for is the manual and the book I referred you.

Regards,

K.

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