[OctDev] Bchenco - Communication Toolbox

[Marco M. <de...@gm...>]

Hi everybody, my name is Marco and this is my first message to the ML.
I've decided to subscribe because i have a little problem usign the
bchenco function provided with the communications toolbox of
octave-forge (versio 1.0.6). I'm currently using Octave 3.0.2. As i can
read on the Function Reference page this function:

"Encodes the message msg using a [n,k] BCH coding. The variable msg is a
binary array with k columns and an arbitrary number of rows. Each row
of msg represents a single symbol to be coded by the BCH coder. The
coded message is returned in the binary array code containing n columns
and the same number of rows as msg."

And after:

"By default the generator polynomial used in the BCH coding is based on
the properties of the Galois Field GF(2^m). This default generator
polynomial can be overridden by a polynomial in g. Suitable generator
polynomials can be constructed with bchpoly."

I'm developing a software that needs a BCH encoder with the following
parameters (among the others...):

- BCH uncoded word length = Kbch = 32208
- BCH coded word length = Nbch = 32400

- BCH uncoded word length = Kbch = 7302
- BCH coded word length = Nbch = 7200

In the first case i use a g polynomial obtained by multiplying 12
polynomials of grade 16. This polynomial generator works correctly with
the other 5 couples (n,k) i need to test on my simulator.

In the second case In the first case i use a g polynomial obtained by
multiplying 12 polynomials of grade 14. This polynomial generator works
correctly with the other 6 couples (n,k) i need to test on my simulator.

Obviously thes are not numbers invented by myself but i'm using a
manual as a reference so i'm sure they are correct.


In both cases i obtain this error:

error: bchenco: can not find valid generator polynomial for parameters
error: evaluating assignment expression near line 140, column 3

I can't properly understand where the problem can be even because i
can't find the source code of this function...

Can anybody explain me why i receive such an error?

Should i post the coefficients of my g polynomial?

Last question (stupid) : when working with octave a polynomial
insertion has always to be done from LSB to MSB am i right?

Thanks a lot

Marco  

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