NEW CODES FOR FEEDBACK COMMUNICATION SYSTEMS.
Final rept. 4 Jan 68-31 Oct 69,
SYLVANIA ELECTRONIC SYSTEMS-EAST WALTHAM MASS COMMUNICATION SYSTEMS DIV
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A number of schemes to improve the quality of data transmission over discrete memoryless and Gaussian noise channels by using a feedback channel are presented, compared, and analyzed. It is indicated that linear schemes cannot achieve an arbitrarily small error probability when a peak-power constraint is applied. Variable geometry schemes are introduced as one possible solution to this difficulty. The binary communication schemes of Turin and of Kramer are presented and developed for the case of bandlimited signals and non-zero error probability. The optimization of the energy distribution for each of the two schemes is presented and the effects of a peak-power constraint are derived. Some new mathematical results are presented for the discrete memoryless and Gaussian noise channels. The error exponents for the binary and M-ary symmetric channels with sequential decision feedback are derived and shown to be less than that for sequential information feedback. For the Gaussian white noise channel, the error exponent of the optimum information feedback scheme subject to a peak-power constraint is evaluated. Author