15 Jul
2013
15 Jul
'13
2:52 p.m.
All of the error correcting block codes used in P25
are the sort where
the codeword includes the encoded data verbatim; the code appends bits
used for error correction, but a receiver can ignore those and just pull
out the data bits. This greatly increases the likelihood of
post-decoding bit errors, but it works fine when the SNR is good.
OK great, so I'll work on the error correction later.
My question now is how are the data bits currently extracted, or
separated, from the extra parity bits? So, from the bit_vector&
frame_body I can extract the 240 bits the LCW information is in; the
question is how do I know where the 12, 6-bit symbols (hex bits or
codewords) are within this 240 bits?
Please excuse me if there is some obvious answer to this, I am asking in
interest of time.
Thanks!