Re: [Discuss-gnuradio] How to calculate BER in different modulations with OFDM using GNURadio Companion

Hi Antonio,

The problem might be due to delay introduced by the processing blocks.

Your OFDM modulator and demodulator don't work instantaneously, they take some time to do their processing and forward their outputs to the next block in line. Therefore, there is a delay between the output of the OFDM demod block and the original signal.

What you need to do is add a delay block between your Random source and the BER block and set the delay properly.

When you're not adding any noise, your BER should be 0. So you can try to find the delay value this way.

Then add noise and see how your BER evolves.

I hope this helps.

Regards,

Jawad

2015-08-31 13:21 GMT+02:00 ANTONIO TAMAYO <atamayo2703@gmail.com>:

The configuration to which I refer in the previous email is the corresponding to the image attached

2015-08-31 13:18 GMT+02:00 ANTONIO TAMAYO <atamayo2703@gmail.com>:

Hello,

 I'm doing my College final project about gnuradio companion. Specifically I have to calculate the BER with OFDM using different modulations to the subcarriers. After that, I have to do a graphic with the BER numbers. The configuration I use is in the image attached.

When I'm using GRC to calculate BER I always have the same problem. First I try to simulate without introducing any noise and get a BER data. Then I try to introduce AWGN noise and the BER data is the same. Clearly I'm making a mistake, but I'm not able to identify what it is. In view of the configuration used, someone could tell me which are my mistakes?

Also, I would like to know how to configure the block Channel Model correctly.

Thank you all.

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