Patents by Inventor Epworth Richard

Epworth Richard has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Reference phase and amplitude estimation for coherent optical receiver
    Patent number: 7469106
    Abstract: An optical receiver demodulates optical orthogonal frequency division multiplexed signals and generates a number of subcarrier reference signals, each for demodulating a frequency channel of the frequency division multiplexed signals. It compensates for degradations in the generated reference signals by averaging a number of estimates derived from different inputs to make the references more resilient to degradations. It can encompass time averaging to compensate for amplification noise, and frequency averaging of phase drift estimation to compensate for phase drift caused by reduced source coherence. It can enable longer system reach and/or increased optical power margins by means of better system resilience to amplification noise and reduced source coherence. The bit error rate can be reduced, and/or the capacity can be increased by increasing bit rate or introducing more frequency channels.
    Type: Grant
    Filed: February 17, 2004
    Date of Patent: December 23, 2008
    Assignee: Nortel Networks Limited
    Inventors: Ricardo Feced, Robin Rickard, Epworth Richard
  • Reference phase and amplitude estimation for coherent optical receiver
    Publication number: 20050180760
    Abstract: An optical receiver demodulates optical orthogonal frequency division multiplexed signals and generates a number of subcarrier reference signals, each for demodulating a frequency channel of the frequency division multiplexed signals. It compensates for degradations in the generated reference signals by averaging a number of estimates derived from different inputs to make the references more resilient to degradations. It can encompass time averaging to compensate for amplification noise, and frequency averaging of phase drift estimation to compensate for phase drift caused by reduced source coherence. It can enable longer system reach and/or increased optical power margins by means of better system resilience to amplification noise and reduced source coherence. The bit error rate can be reduced, and/or the capacity can be increased by increasing bit rate or introducing more frequency channels.
    Type: Application
    Filed: February 17, 2004
    Publication date: August 18, 2005
    Inventors: Ricardo Feced, Robin Rickard, Epworth Richard