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Systems and method for orthogonal frequency divisional multiplexing

  • US 7,881,180 B2
  • Filed: 10/29/2007
  • Issued: 02/01/2011
  • Est. Priority Date: 02/06/1995
  • Status: Expired due to Fees
First Claim
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1. A remote communication device using minimum allocations in a multipoint-to-point communication system, the device comprising:

  • at least one symbol mapper that maps data into symbols using quadrature amplitude modulation (QAM) symbol mapping and phase-shift keying (PSK) symbol mapping;

    a Fast Fourier Transform (FFT) engine that receives a frame of parallel data based on symbol data generated by the symbol mapper, the Fast Fourier Transform (FFT) engine generating a frame of time domain in-phase and quadrature phase data from the symbol data generated by the symbol mapper;

    at least one converter generating an analog signal based on the stream of time domain in-phase and quadrature phase data;

    a radio frequency transmitter for transmitting a radio frequency signal based on the analog signal;

    wherein the radio frequency signal comprises a plurality of orthogonal frequency division multiplexing (OFDM) sub-carriers transmitted by the transmitter, the plurality of OFDM sub-carriers synchronized in time and frequency to combine with OFDM sub-carriers transmitted by at least one other transmitter to form a composite OFDM waveform at a host unit;

    wherein the minimum bandwidth allocation received by the remote communication device from the host unit for upstream payload comprises at least two OFDM sub-carriers within the composite OFDM waveform available for transmitting the radio frequency signal.

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