The author presents a comprehensive discussion of three major aspects of the work of the Consultative Committee for Space Data Systems (CCSDS), a worldwide cooperative effort of national space agencies. The author examines the CCSDS space data communications network concept on which the data communications facilities of future advanced orbiting systems will be based. He derives the specifications of an open communications architecture as a reference model for the development of services and protocols that support the transfer of information over space data communications networks. Detailed specifications of the communication services and information transfer protocols that have reached a high degree of maturity and stability are offered. The author also includes a complete list of currently available CCSDS standards and supporting documentation.>

It is shown that the only modification of the Berlekamp algorithm required to decode the class of alternant codes consists of a linear transformation of the syndromes prior to the application of the algorithm. Since alternant codes include all Bose-Chaudhuri-Hocquenghem (BCH) and Goppa codes, the Chien-Choy generalized BCH codes, and the generalized Srivastava codes, all of these can be decoded with no increase in complexity over BCH decoding.

Quick-look nonsystematic convolutional codes have the property that the information sequence may be recovered from the encoded sequence in straightforward fashion and with a minimum of error amplification. In this concise paper we investigate their relevant characteristics for constraint lengths less than eight and rate\frac{1}{2}and obtain a number of interesting and practically useful results. In particular, for the best of these codes, we derive their free distance and error amplification, their decoded bit error probability when used over the binary symmetric channel in conjunction with Viterbi decoding, and show how they can be employed to measure the channel bit error rate.

This paper presents a table of upper and lower bounds ond_{max} (n,k), the maximum minimum distance over all binary, linear(n,k)error-correcting codes. The table is obtained by combining the best of the existing bounds ond_{max} (n,k)with the minimum distances of known codes and a variety of code-construction techniques.

By shortening certain binary primitive BCH codes, we derive a number of linear error-correcting codes with minimum distances superior to any known previously. We also give the weight spectra of three nonprimitive BCH codes whose minimum distances likewise constitute a significant improvement over those of the best codes previously known.

Srivastava codes, a class of linear noncyclic error-correcting codes, offer performance potentially superior tO that of comparable BCH codes. Their properties are investigated by equivalence classification and subsequent computer evaluation of their weight spectra. In the process a constructive upper bound is obtained on the number of equivalence classes of Srivastava codes, a class of binary Srivastava codes whose parity-check matrices have row rank less than the maximum, and a class of binary double-error,correcting codes w!th highly structured parity-check matrices. A number of shortened binary Srivastava codes with minimum distances superior to those of the best comparable linear codes known are also presented.

This paper is concerned with the structure of a partial ordering of discrete, memoryless communication channels. These are identified with equivalence classes of stochastic matrices into which the set of all stochastic matrices is partitioned by a relation of matrix inclusion. The relation carries over to channels and induces a partial ordering on them, having the property that ifK_{1}andK_{2}are channels such thatK_{1}includesK_{2}, then if a code exists forK_{2}, there exists a code forK_{1}, whose probability of error is never greater than that of the code forK_{2}. Results are derived which specify the equivalence classes of stochastic matrices corresponding to the binary and the symmetric channels and resolve the structure of the partial ordering between them.

This paper concerns itseff with certain upper and lower bounds on the capacity of arbitrary discrete, memoryless channels. A given channel is related to ann-ary symmetric channel through a series of operations on the channel matrix, none of which can increase capacity. The bounds are then obtained from the known formula for capacity of a symmetric channel.