Accession Number : AD0665355

Title :   COMMUNICATION OVER FADING DISPERSIVE CHANNELS.

Descriptive Note : Technical rept.,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE RESEARCH LAB OF ELECTRONICS

Personal Author(s) : Richters,John S.

Report Date : 30 NOV 1967

Pagination or Media Count : 149

Abstract : The transmission of digital information over a fading dispersive channel is considered, subject to a bandwidth constraint on the input signals. A specific signaling scheme is proposed, in which information is transmitted with signals formed by coding over a set of smaller basic signals, all of which excite approximately independent and orthogonal outputs. The problem is then modeled as one of block coding over successive independent uses of a diversity channel. Upper and lower bounds to the minimum error probability attainable by such a scheme are derived. These bounds are exponentially decreasing in terms of the time available for information transmission, and agree asymptotically for a range of rates. These bounds are used to interpret the significance of different signal and channel parameters, and the interplay between them. Some conclusions are drawn concerning the nature of good input signals, the major one being that any basic signal should be transmitted at one of a small number of discrete voltage levels. Several numerical examples are included, to illustrate how these results may be applied in the estimation of performance levels for practical channels. (Author)

Descriptors :   (*COMMUNICATION AND RADIO SYSTEMS, PERFORMANCE(ENGINEERING)), DIGITAL SYSTEMS, IONOSPHERIC PROPAGATION, RADIO SIGNALS, SCATTERING, ERRORS, CODING, ATTENUATION, BANDWIDTH, MATHEMATICAL MODELS, THESES

Subject Categories : Cybernetics
      Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE