IMPROVEMENT OF TWO-WAY COMMUNICATION BY MEANS OF FEEDBACK
Abstract
A general synthesis technique is presented for feedback systems with block codes. A theorem is derived which shows the equivalence in performance between various feedback systems. Codes for transmitting the decision signal are discussed, and a state transition diagram for analyzing the effects of decision signal errors is introduced. A conclusion which can be drawn from the theoretical developments is that decision feedback is the basic and most desirable form to use for simultaneous communication in both directions. Compound and information feedback should play supplementary roles and should be called upon only to speed up to transmission in one direction if the other channel is not in use for message transmission. In switching a two-way decision-feedback system to a compound- or information-feedback system little added equipment is necessary. The improvement of feedback systems over unidirectional systems can be readily estimated for channels with independent errors. However, the improvement is much greater under fading situations (or long burst errors), as is illustrated in an example. The methods discussed are general and versatile enough to cope with practically any situation. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 15, 1961
- Accession Number
- AD0259141
Entities
People
- Charles F. Hobbs
- Harold K. Work
- Leonard S. Schwartz
Organizations
- New York University