The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 24, 2004
Filed:
Oct. 22, 1999
Robert Fifield, Redhill, GB;
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
A method of operating a radio communication system uses orthogonal signals for transmission of packets of data between two or more stations. In the transmitter data is encoded onto a plurality of orthogonal carriers by a differential phase modulation technique, for example DQPSK. The carriers are combined into a single signal by an inverse discrete Fourier transform and clipped at a predetermined amplitude before being transmitted to reduce the crest factor of the transmitted signal. The phase of one or more of the carriers is randomized before each data packet, hence a different crest factor will result for retransmissions of the same packet. This ensures that if a packet is difficult to transmit, because of reduced signal to noise ratio caused by clipping, it will retransmit successfully.