131x0b2ec1

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Unformatted text preview: sing the following equation: L = (255-2E-q) I such that L is a positive integer, where E = error correction capability, q = number of virtual fill symbols per R-S codeword, and I = interleaving depth. 10.5.4 When 32-bit compatibility is required, the Transfer Frame length must be chosen so that a) it is expressed by the equation in 10.5.3; and b) the codeblock length (255-q)I (in octets) is a multiple of 4. 10.6 CASE 4: CONCATENATED The allowable lengths of Transfer Frames when the concatenated (Reed-Solomon and convolutional) coding is used are the same as those for the Reed-Solomon–only case (Case 3) shown in 10.5. 10.7 CASE 5: TURBO 10.7.1 The Transfer Frame lengths shall be selected to match the information block lengths for the selected Turbo code. NOTE – The Turbo Codes specified in section 5 of this Recommended Standard are block codes. 10.7.2 Only the following information block lengths shall be used (values are in octets): a) 223; b) 446; c) 892; d) 1115. CCSDS 131.0-B-2 Page 10-2 August 2011 CCSDS RECOMMENDED STANDARD FOR TM SYNCHRONIZATION AND CHANNEL CODING NOTE – Performance for only the above block lengths (i.e., Transfer Frame lengths) has been validated by CCSDS and approved for use (values are in octets). 10.8 CASE 6: LDPC 10.8.1 The Transfer Frame lengths must match the information block lengths for the selected LDPC code. NOTE – The LDPC Codes specified in section 7 of this Recommended Standard are block codes. 10.8.2 When the rate-7/8 LDPC code is used, the only allowable Transfer Frame length is 892 octets. 10.8.3 When the 1/2-, 2/3-, and 4/5-rate LDPC codes are used, the allowable Transfer Frame lengths are 128 octets, 512 octets, or 2048 octets. CCSDS 131.0-B-2 Page 10-3 August 2011 CCSDS RECOMMENDED STANDARD FOR TM SYNCHRONIZATION AND CHANNEL CODING 11 MANAGED PARAMETERS 11.1 OVERVIEW In order to conserve bandwidth on the space link, some parameters associated with synchronization and channel coding are handled by management rather than by inline communications protocol. The managed parameters are those whi...
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This document was uploaded on 03/06/2014.

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