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[SOLVED] DVB-T2 pilot insertion PN sequence used in the reference sequence

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DVB-T2 pilot insertion PN sequence used in the reference sequence ????!!!!

hi everybody ;h r u??

i am working on the ofdm transmission and reception part in DVB-T2 standard
so for the pilot insertion there is something called reference sequence which uses both PRBS and PN sequences.
my problem is that for the PN sequence i am not given any polynomial generator equation, i am only given the maximum length for each FFT mode and PN sequence frame level hexadecimal description

so can any one please tell me how to implement this PN sequence using matlab ????? or in other words how to get the polynomial equation based on the previously mentioned situation ????

note that it also said in the standard :The overall PN-sequence has been optimized by fragment by using as starting point the fully optimized short PN-sequence of length 15. Each relevant length of a given PN-sequence derives from this latter sequence

i don't understand this statement, can any one explain it, i think it may help

thanks in advance
 

Re: DVB-T2 pilot insertion PN sequence used in the reference sequence

The relevant part of the specification is the part immediately above the note that you are quoting, that says "The sequence (pn0, pn1...pnNPN-1) of length NPN =LF, shall be formed by taking the first NPN bits from an overall PN-sequence. The overall PN-sequence is defined by table 56, and each four binary digits of the overall sequence are formed from the hexadecimal digits in table 56 taking the MSB first."

i.e., you should literally take the sequence from the table. The note is simply informative and explains how the sequence was arrived at, but it's the hex sequence in the table that specifies the sequence to be used. So you can just copy the hex string into the MATLAB code and convert it as required.

The DVB-T2 group are hoping to upload a release of an open source T2 coder/decoder software platform to SourceForge sometime this week, and there are also test streams available ( **broken link removed** ). Both of these might be useful to you. Particularly the simulation platform, since it's in MATLAB already. The SourceForge project at DVB-T2 Common Simulation Platform | Download DVB-T2 Common Simulation Platform software for free at SourceForge.net has been created but there is no code there yet.

I hope this helps.
 
---------- Post added 23-02-11 at 00:06 ---------- Previous post was 22-02-11 at 23:40 ----------

ndw said:
Re: DVB-T2 pilot insertion PN sequence used in the reference sequence

The relevant part of the specification is the part immediately above the note that you are quoting, that says "The sequence (pn0, pn1...pnNPN-1) of length NPN =LF, shall be formed by taking the first NPN bits from an overall PN-sequence. The overall PN-sequence is defined by table 56, and each four binary digits of the overall sequence are formed from the hexadecimal digits in table 56 taking the MSB first."

i.e., you should literally take the sequence from the table. The note is simply informative and explains how the sequence was arrived at, but it's the hex sequence in the table that specifies the sequence to be used. So you can just copy the hex string into the MATLAB code and convert it as required.

The DVB-T2 group are hoping to upload a release of an open source T2 coder/decoder software platform to SourceForge sometime this week, and there are also test streams available ( **broken link removed** ). Both of these might be useful to you. Particularly the simulation platform, since it's in MATLAB already. The SourceForge project at DVB-T2 Common Simulation Platform | Download DVB-T2 Common Simulation Platform software for free at SourceForge.net has been created but there is no code there yet.

I hope this helps.
Click to expand...

thank u very much,i have tried and copied the hexdecimal sequence part by part and converted it to bits using matlab then i added them together as on vector,so i think what u said is very reasonable way to implement this sequence
again thank u so much for ur help:-D:-D;-)
 
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