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Apparatus and method for improved performance in radio telecommunication systems that use pulse-shaping filters

  • US 7,400,686 B2
  • Filed: 12/22/2003
  • Issued: 07/15/2008
  • Est. Priority Date: 07/25/2002
  • Status: Expired due to Fees
First Claim
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1. An apparatus comprising:

  • a transmitter for transmitting a time domain signal, wherein the transmitter comprises;

    an orthogonal frequency division multiplexing (OFDM) modulator that divides a modulated information-bearing signal into a plurality of streams, spreads each of the plurality of streams with a spreading code, sums the spread streams into an input vector X of length Nb, divides the input vector X of length Nb into two parts, inserts Nx zeros between the two parts, and takes an inverse fast Fourier transform (IFFT) of size NbNx to obtain a time-domain signal; and

    a pulse-shaping filter coupled to the OFDM modulator for processing the time-domain signal prior to transmission; and

    a receiver for receiving the transmitted time-domain signal, wherein the receiver comprises an OFDM demodulator for taking a fast Fourier transform (FFT) of size NbNx of the received signal and removes the zeros inserted in the transmitter from the resulting frequency-domain signal.

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