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Time varying delay diversity of OFDM

  • US 8,233,555 B2
  • Filed: 03/10/2005
  • Issued: 07/31/2012
  • Est. Priority Date: 05/17/2004
  • Status: Active Grant
First Claim
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1. A wireless transmitter, comprising:

  • at least three antennas; and

    a memory coupled with the at least three antennas, the memory storing a plurality of symbols each comprising a plurality of samples,wherein the plurality of samples of a first symbol of the plurality of symbols are provided to one antenna of the at least three antennas after a first delay period, and the plurality of samples of a second symbol of the plurality of symbols are provided to the one antenna after a second delay period, wherein the first delay period and the second delay period are different, each of the symbols comprising a cyclic prefix of one or more samples, wherein the delay periods that vary according to a defined time varying function are limited based on a number of symbols in a frame, burst period or symbol stream; and

    wherein the plurality of samples of the first symbol are provided to another of the at least three antennas after a third delay period and the plurality of samples of the second symbol are provided to the another antenna after a fourth delay period, wherein the first delay period, second delay period, third delay period, and fourth delay period are all different from each other, wherein the second delay period varies by n*β

    samples from the first delay period and the fourth delay period varies by n*(β

    +k) samples from the third delay period, where n is a location of a symbol in a symbol stream and β and

    k are constants, and wherein time diversity is provided even if a channel is not of itself time selective.

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