Unformatted text preview: ed to
the data stream.
Punctured Code: As used in this document, a code obtained by deleting some of the parity
symbols generated by the convolutional encoder before transmission. The bandwidth
efficiency obtained by puncturing is increased compared to the original code, although the
minimum weight (and therefore its error-correcting performance) will be less than that of the
Reed-Solomon (R-S) Symbol: A set of J bits that represents an element in GF(2J), the code
alphabet of a J-bit Reed-Solomon code.
Systematic Code: A code in which the input information sequence appears in unaltered
form as part of the output codeword.
Transparent Code: A code that has the property that complementing the input of the
encoder or decoder results in complementing the output.
Trellis Termination: The operation of filling with zeros the s stages of each shift register
used in the Turbo encoder, after the end of the information block. During trellis termination
the encoders continue to output encoded symbols for s-1 additional clock cycles. CCSDS 131.0-B-2 Page D-3 August 2011 CCSDS RECOMMENDED STANDARD FOR TM SYNCHRONIZATION AND CHANNEL CODING Turbo Code: As used in this document, a block code formed by combining two component
recursive convolutional codes. A Turbo code takes as input a block of k information bits.
The input block is sent unchanged to the first component code and bit-wise interleaved (see
Turbo Code Permutation) to the second component code. The output is formed by the parity
symbols contributed by each component code plus a replica of the information bits.
Turbo Code Permutation: A fixed bit-by-bit permutation of the entire input block of
information bits performed by an interleaver, used in Turbo codes.
Virtual Fill: In a systematic block code, a codeword can be divided into an information part
and a parity (check) part. Suppose that the information part is k symbols long (a symbol is
defined here to be an element of the code’s alphabet) and that the parity par...
View Full Document
This document was uploaded on 03/06/2014.
- Spring '14