Hi Adeel,
Thanks for your prompt reply!
I don't quite understand your last email. If I want to test the performance of
transmission under different power allocation. What should I do? Can you please
be more specific about this?
Currently, what I'm doing is keep the tx-amplitude 0.2, and change the gain
from 35 to 65. You mean in this range, the power is not liner to gain change,
right? If so, is there any way to control or influence the power change?
Thank you!
Regards,
Ada
Date: Wed, 24 Jul 2013 06:12:15 +0500
Subject: Re: [Discuss-gnuradio] how to raise the packet error rate in benchmark
From: adeela...@gmail.com
To: yeran0...@hotmail.com; discuss-gnuradio@gnu.org
Ada,
>>once the signal has been up converted. Now I'm using 0.2 amplitude and
35 gain. But I don't understand, how come that the smaller the power is,
the better transmission performance there will be. And also, why does
power should be in the range of 0 to 1.0? How to calculate transmission
power using the -tx-amplitude and tx-gain?
Better performance is not due to smaller power but it is due to the non-linear
effects of RF-amplifiers. As per my observations, Tx-Dsp amplitude beyond 0.15
to 0.2 causes the USRP daughter-boards Tx-amplification-stage to go into
non-linear region thus error-rate of PSK/QAM increases. Non-linear modulation
e.g. FSK/GMSK are more robust to Amps non-linear effects. so u can experiment
increasing TX-amplitude both for FSK-variants & PSK/QAM and observe performance.
-Adeel
On Tue, Jul 23, 2013 at 9:25 PM, yeran <yeran0...@hotmail.com> wrote:
Hi everyone,
I'm doing a project on joint decode. But my problem is that in the lab
environment, the benchmark transmission is always good, there are hardly any
packet loss, so I can not show the advantage of joint decode.
I've tried to change the physical distance from transmission to receiver
attenna. Still works really well even put in opposite side of the building.
I've tried to change the transmission power and transmission rate. Inspired by
some previous study, I learned that transmission power is controlled by
-tx-amplitude and -tx-gain, in which -tx-amplitude sets the amplitude of the
signal going into the DAC. RF gain is applied in the daughtercard once the
signal has been up converted. Now I'm using 0.2 amplitude and 35 gain. But I
don't understand, how come that the smaller the power is, the better
transmission performance there will be. And also, why does power should be in
the range of 0 to 1.0? How to calculate transmission power using the
-tx-amplitude and tx-gain?
Is there any other way that may cause more error in transmission beside the
ones I mentioned?
Thanks in advance! Any suggestion will be greatly appreciated!
Ada
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