On the minimum distance problem for faster-than-Nyquist signaling.

Motivated by recent work of D. J. Hajela, we here reconsider the problem of determining the minimum distance between uncoded binary data sequences which have been transmitted through an ideal bandlimiting channel at a rate exceeding Nyquist. This distance is the main parameter determining the error rate for recovery of the data in noise. We show for signaling rates up to about 25 percent faster than the Nyquist rate, that the minimum distance does not drop below the pulse energy, the value which it would have in the ideal intersymbol interference- free case.