Patents by Inventor Keijo Ruotsalainen

Keijo Ruotsalainen 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).

  • Method and apparatus for modulation using an at least four-dimensional signal constellation
    Patent number: 7230993
    Abstract: A digital communication system (20) in which a signal constellation (30) of a dimensionality of at least four is used, with distance properties chosen to reduce the bit error rate compared to that of digital communication systems using signal constellations of half the dimensionality. A symbol generator (21) uses the higher dimensional signal constellation (30), or any orthogonal transformation of the higher dimensional signal constellation (30), to translate a bit stream into a stream of higher dimensional symbols, which it then provides to a modulator (22). The modulator (22) transmits each higher dimensional symbol in at least two parts, using a modulation scheme according to the prior art, such as QAM or QPSK.
    Type: Grant
    Filed: March 6, 2002
    Date of Patent: June 12, 2007
    Assignee: Nokia Corporation
    Inventors: Keijo Ruotsalainen, Markku Heikkilä
  • Method and apparatus for modulation using an at least four-dimensional signal constellation
    Publication number: 20030169830
    Abstract: A digital communication system (20) in which a signal constellation (30) of a dimensionality of at least four is used, with distance properties chosen to reduce the bit error rate compared to that of digital communication systems using signal constellations of half the dimensionality. A symbol generator (21) uses the higher dimensional signal constellation (30), or any orthogonal transformation of the higher dimensional signal constellation (30), to translate a bit stream into a stream of higher dimensional symbols, which it then provides to a modulator (22). The modulator (22) transmits each higher dimensional symbol in at least two parts, using a modulation scheme according to the prior art, such as QAM or QPSK.
    Type: Application
    Filed: March 6, 2002
    Publication date: September 11, 2003
    Applicant: NOKIA CORPORATION
    Inventors: Keijo Ruotsalainen, Markku Heikkila