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
Date: Wed, 24 Jul 2013 06:12:15 +0500
Subject: Re: [Discuss-gnuradio] how to raise the packet error rate in
From: [email protected]
To: [email protected]; [email protected]
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.
On Tue, Jul 23, 2013 at 9:25 PM, yeran [email protected] wrote:
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
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!
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