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Thread Subject:
How to check which digital signal was originally transmitted from group of known digital signals on receiver side?

Subject: How to check which digital signal was originally transmitted from group of known digital signals on receiver side?

From: Muhammad Nabeel

Date: 15 Jun, 2013 06:35:11

Message: 1 of 5

I am working in Simulink. At transmitter side I have some digital data (Let say of 10 bits with simply data rate 1 bit/sec) which I can see through scope as unipolar digital data. On receiver side let suppose I am unaware what was originally transmitted digital data but what I know is that the transmitted digital sequence must be from one of the ten known signals (if already added as a library) on receiver side. So I want to compare the received signal with ten known sequences one by one to check which digital signal among them was actually transmitted. I am not that much expert.

Kindly tell me should I use correlation for comparison of this digital data or any other thing. I will wait for your response.

Also can I do all this in Simulink? As I can do this with scope waveform by comparing waveform of received digital signal with available known waveforms one by one to check which waveform matches more OR should I import the data to MATLAB and should perform some comparison there?

Also the received waveform is little much distorted because of channel noise etc.

Thanks in advance.

Subject: How to check which digital signal was originally transmitted from group of known digital signals on receiver side?

From: Teresa Hubscher-Younger

Date: 18 Jun, 2013 08:57:09

Message: 2 of 5

Have you tried the Simulink Data Inspector?
http://www.mathworks.com/help/simulink/ug/simulation-data-inspector-overview.html

It gives you some functionality for comparing signal data:
http://www.mathworks.com/help/simulink/ug/comparison-of-signal-data.html

HTH,
Teresa

"Muhammad Nabeel" wrote in message <kph1uv$kdk$1@newscl01ah.mathworks.com>...
> I am working in Simulink. At transmitter side I have some digital data (Let say of 10 bits with simply data rate 1 bit/sec) which I can see through scope as unipolar digital data. On receiver side let suppose I am unaware what was originally transmitted digital data but what I know is that the transmitted digital sequence must be from one of the ten known signals (if already added as a library) on receiver side. So I want to compare the received signal with ten known sequences one by one to check which digital signal among them was actually transmitted. I am not that much expert.
>
> Kindly tell me should I use correlation for comparison of this digital data or any other thing. I will wait for your response.
>
> Also can I do all this in Simulink? As I can do this with scope waveform by comparing waveform of received digital signal with available known waveforms one by one to check which waveform matches more OR should I import the data to MATLAB and should perform some comparison there?
>
> Also the received waveform is little much distorted because of channel noise etc.
>
> Thanks in advance.

Subject: How to check which digital signal was originally transmitted from group of known digital signals on receiver side?

From: Muhammad Nabeel

Date: 25 Jun, 2013 07:14:07

Message: 3 of 5

Really thanks for the reply.

I will definitely look at the links you have referred and will provide you a feedback.

In continuation of the above question I have another question. If the problem of knowing that this specific digital waveform was transmitted is solved.

Now I have a collided response of two digital wave forms from two different receivers at the same time (modulated with a same carrier and from a wireless channel) which are added before entering into the receiver as a collision. After demodulating it and low pass filtering I am getting the added waveform of transmitted digital signals with a little much noise or distortion. I am aware that the response I got is added response of two transmitters and both the transmitters have chosen there digital signal wave form from those 10 known wave forms of the receiver but having varied amplitude, how will I be able to know that in collision these two specific wave forms are involved from group of known sequences or wave forms?

I have a rough idea that if I subtract each known sequence one by one from the received wave form in time domain and match/correlate the result with all of the available sequences/wave forms every time after each subtraction process. If the result matches more with one of the known sequence I will get know that one of the collided sequence was this one and obviously the other one will be the subtracted one I used before correlating the whole group...

But I am not getting good results, may be because every time transmitter uses different amplitude of each waveform rather than fixed one?

I will wait for you response. Thanks.

Subject: How to check which digital signal was originally transmitted from group of known digital signals on receiver side?

From: Muhammad Nabeel

Date: 25 Jun, 2013 07:34:09

Message: 4 of 5

Correction: In the last post (fourth paragraph first line) it is a mistake "from two different receivers", actually I mean "from two different transmitters".

Subject: How to check which digital signal was originally transmitted from group of known digital signals on receiver side?

From: Muhammad Nabeel

Date: 14 Jul, 2013 19:02:10

Message: 5 of 5

Why I am not getting the reply :(

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