BS ISO 22642:2015 pdf download

BS ISO 22642:2015 pdf download.Space data and information transfer systems — TC synchronization and channel coding
1.7 REFERENCES
The following documents contain provisions which, through reference in this text, constitute provisions of this Recommended Standard. At the time of publication, the editions indicated were valid. All documents are subject to revision, and users of this Recommended Standard are encouraged to investigate the possibility of applying the most recent editions of the documents indicated below. The CCSDS Secretariat maintains a register of currently valid CCSDS Recommended Standards.
[1] TC Space Data Link Protocol . Recommendation for Space Data System Standards,CCSDS 232.0-B-2. Blue Book. Issue 2. Washington, D.C.: CCSDS, July 2010.
[2] Information Technology—Open Systems Interconnection—Basic Reference Model:The Basic Model . International Standard, ISO/IEC 7498-1. 2nd ed. Geneva: ISO,1994.
[3] Information Technology—Open Systems Interconnection—Basic Reference Model—Conventions for the definition of OSI services . International Standard, ISO/IEC 10731:1994. Geneva: ISO, 1994.
[4] Radio Frequency and Modulation Systems—Part 1: Earth Stations and Spacecraft .Recommendation for Space Data System Standards, CCSDS 401.0-B-20. Blue Book.Issue 20. Washington, D.C.: CCSDS, April 2009.
[5] Space Link Extension—Forward CLTU Service Specification . Recommendation for Space Data System Standards, CCSDS 912.1-B-3. Blue Book. Issue 3. Washington,D.C.: CCSDS, July 2010.
NOTE – Informative references are listed in annex C.
2 OVERVIEW
2.1 ARCHITECTURE
Figure 2-1 illustrates the relationship of this Recommended Standard to the Open Systems Interconnection (OSI) reference model (reference [2]). Two sublayers of the Data Link Layer are defined for CCSDS space link protocols. The TC Space Data Link Protocols specified in reference [1] corresponds to the Data Link Protocol Sublayer, and provides functions for transferring data using the protocol data unit called the Transfer Frame. The Synchronization and Channel Coding Sublayer provides additional functions necessary for transferring Transfer Frames over a space link. These functions are error-control coding/decoding, delimiting/synchronizing codeblocks, and bit transition generation/removal.
2.2.2 ERROR-CONTROL CODING
This Recommended Standard specifies an error-control coding method using a modified BCH code. This is described in section 3. The modified BCH code specified in this Recommended Standard may be decoded either in an error-detecting mode or in an error-correcting mode, depending on mission requirements. If the modified BCH code is decoded in an error-detecting mode, the Frame Error Control Field (FECF) defined in reference [1] may be used to reduce the probability of undetected errors. NOTE – In this Recommended Standard, the characteristics of the codes are specified only to the extent necessary to ensure interoperability and cross-support. The specification does not attempt to quantify the relative coding gain or the merits of each approach discussed, nor the design requirements for encoders or decoders.