3 the asm can be acquired either in the channel

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: f the pseudo-random generator, if used (see section 9). It is also useful in assisting the node synchronization process of the decoder for the convolutional code. For a coding system using the basic convolutional code specified in 3.3, the ASM can be acquired either in the channel symbol domain (i.e., before any decoding) or in the domain of bits decoded by the convolutional decoder. For a concatenated Reed-Solomon and convolutional coding system using the basic convolutional code specified in 3.3, the ASM can be acquired either in the channel symbol domain (i.e., before any decoding) or in the domain of bits decoded by the inner code (i.e., the code symbol domain of the Reed-Solomon code). For a coding system using the punctured convolutional codes specified in 3.4, the ASM can only be acquired in the domain of bits decoded by the convolutional decoder. It cannot be acquired in the channel symbol domain (i.e., before any decoding). For a concatenated Reed-Solomon and convolutional coding system using the punctured convolutional codes specified in 3.4, the ASM can only be acquired in the domain of bits decoded by the inner code (i.e., the code symbol domain of the Reed-Solomon code); i.e.; it cannot be acquired in the channel symbol domain (i.e., before any decoding). For a Turbo or LDPC coding system, the ASM can only be acquired in the channel symbol domain (i.e., before any decoding in the code symbol domain of the Turbo or LDPC code). 8.1.2 CHANNEL ACCESS DATA UNIT The data unit that consists of the ASM and the Transfer Frame (if the Physical Channel is not Reed-Solomon, Turbo, or LDPC coded) or the Reed-Solomon Codeblock or Turbo or LDPC Codeword (if the Physical Channel is Reed-Solomon, Turbo, or LDPC coded) is called the Channel Access Data Unit (CADU). The Transfer Frame, Codeword, or Codeblock in the CADU may or may not be randomized. CCSDS 131.0-B-2 Page 8-1 August 2011 CCSDS RECOMMENDED STANDARD FOR TM SYNCHRONIZATION AND CHANNEL CODING 8.2 THE ATTACHED SYNC MARKER (ASM) 8.2.1.1 Reed-Solomon Codeblocks or Turbo or LDPC Codewords (or Transfer...
View Full Document

This document was uploaded on 03/06/2014.

Ask a homework question - tutors are online