Ccsds 1320 b 1 page 2 12 september 2003 ccsds

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: e identifier. CCSDS 132.0-B-1 Page 2-12 September 2003 CCSDS RECOMMENDATION FOR TM SPACE DATA LINK PROTOCOL Packet Service VC Access VC_FSH Service Service Packet VCA_SDU VC_FSH VC_OCF Service VC_OCF VC Frame Service MC_FSH Service MC_OCF Service VC Frame VCID MC_FSH MC_OCF MC Frame Service MC Frame MCID All Frames Key Commutator/ Decommutator Multiplexer/ Demultiplexer Figure 2-7: TM Space Data Link Protocol Channel Tree 2.4 SERVICES ASSUMED FROM LOWER LAYERS 2.4.1 SERVICES ASSUMED FROM THE SYNCHRONIZATION AND CHANNEL CODING SUBLAYER As described in 2.1.1, the TM Synchronization and Channel Coding Recommendation (reference [3]) must be used with the TM Space Data Link Protocol as the Synchronization and Channel Coding Sublayer specification. The functions provided by the TM Synchronization and Channel Coding Recommendation are as follows: a) error control encoding and decoding functions (optional); b) bit transition generation and removal functions (optional); c) delimiting and synchronizing functions. The Synchronization and Channel Coding Sublayer, then, transfers contiguous, fixed-length, delimited protocol data units as a contiguous stream of bits over a space link using the services of the underlying Physical Layer. CCSDS 132.0-B-1 Page 2-13 September 2003 CCSDS RECOMMENDATION FOR TM SPACE DATA LINK PROTOCOL 2.4.2 PERFORMANCE REQUIREMENTS TO LOWER LAYERS The coding options of the TM Channel Coding and Synchronization Recommendation and the performance of the RF link provided by the Physical Layer shall be chosen according to the following criteria: a) the probability of misidentifying the MCID and VCID shall be less than a missionspecified value; b) the probability of not correctly extracting Packets from Transfer Frames using the First Header Pointer and the Packet Length Field shall be less than a missionspecified value. In order to assure correct decoding at the receiving end, the same coding options must be applied to all Transfer Frames of a Physical Channel. CCSDS 132.0-B-...
View Full Document

Ask a homework question - tutors are online