Ronald D Huff

US Patent:

6477208, Nov 5, 2002

Filed:

Aug 30, 2000

Appl. No.:

09/651302

Inventors:

Ronald J Huff - Sunnyvale CA

Assignee:

ComTier - Sunnyvale CA

International Classification:

H04L 512

US Classification:

375265, 714786, 714796

Abstract:

This invention provides a method and apparatus for processing a received digitally-modulated carrier signal to coherently demodulate or, for some applications, coherently demodulate and decode said signal when the signals phase has an undesired component and/or to generate successive estimated values of said undesired phase of the received signal. Signal processing operations are performed in accord with a composite trellis diagram formed from one or more component trellis diagrams that are phase-displaced versions of a root trellis diagram and, when applicable, phase migration transitions. Desired variations in signal parameter values that result from modulating the signal effect transitions between states in the root trellis diagram. For some embodiments of this invention, phase migration transitions which typically recur periodically in the composite trellis diagram accommodate undesired variations in the received signals phase for which the rate of change in phase is adequately small relative to the modulation rate but not otherwise restricted. The applicable signal processing is implemented through appropriate application of the Viterbi maximum likelihood processing algorithm or any variant, derivative or counterpart thereof.

US Patent:

59740914, Oct 26, 1999

Filed:

Oct 30, 1997

Appl. No.:

8/961324

Inventors:

Ronald J Huff - Sunnyvale CA

Assignee:

Communication Network Systems - Santa Clara CA

International Classification:

H04L 512
H04L 2302

US Classification:

375265

Abstract:

This invention provides means for processing a received digitally-modulated carrier signal to coherently demodulate or, for some applications, coherently demodulate and decode said signal when the signal's phase has an undesired component and/or to generate successive estimated values of said undesired phase of the received signal. The signal processed is partially represented by a composite trellis diagram formed by combining multiple component trellis diagrams which are phase-displaced versions of a root trellis diagram. Desired variations in signal parameter values that result from modulating the signal effect transitions between states within the root trellis diagram. For some embodiments of this invention, transitions between states within different component trellis diagrams for which phase values are proximate, trellis coupling transitions, are incorporated into the composite trellis diagram in a periodic manner to accommodate undesired variations in the received signal's phase for which the rate of change in phase is adequately small relative to the modulation rate but not otherwise restricted. The received signal is processed in accord with the composite trellis diagram through appropriate application of the Viterbi maximum likelihood processing algorithm or any sub-optimum variant, derivative or counterpart thereof. A demodulated data sequence and/or a sequence of estimated values of the received signal's phase are derived from appropriately structured path history values generated for the multiple states in the composite trellis diagram.