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Efficient shadow reduction antenna system for spread spectrum

  • US 6,128,330 A
  • Filed: 11/24/1998
  • Issued: 10/03/2000
  • Est. Priority Date: 11/24/1998
  • Status: Expired due to Term
First Claim
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1. An antenna system employing space diversity and coding, for transmitting data having symbols, over a communications channel having fading caused by multipath and shadowing, comprising:

  • a forward-error-correction (FEC) encoder for FEC encoding the data, thereby generating FEC data;

    an interleaver, coupled to said FEC encoder, for interleaving the symbols of the FEC data, thereby generating interleaved data;

    a demultiplexer coupled to said interleaver, for demultiplexing the interleaved data into a plurality of subchannels of data;

    a plurality of spread-spectrum devices coupled to said demultiplexer, for spread-spectrum processing the plurality of subchannels of data with a plurality of chip-sequence signals, respectively, with each chip-sequence signal different from other chip-sequence signals in the plurality of chip-sequence signals, thereby generating a plurality of spread-spectrum-subchannel signals, respectively;

    a plurality of transmit antennas, coupled to said plurality of spread-spectrum devices, respectively, with each transmitter antenna of said plurality of transmit antennas spaced from other transmit antennas of said plurality of transmit antennas, for radiating at a carrier frequency, using radiowaves, the plurality of spread-spectrum-subchannel signals, respectively, over the communications channel, as a plurality of spread-spectrum signals;

    said communications channel imparting fading on the plurality of spread-spectrum signals, thereby generating a multiplicity of fading spread-spectrum signals;

    a plurality of receiver subsystems, coupled to the communications channel, for receiving the plurality of spread-spectrum signals and the multiplicity of fading spread-spectrum signals from the communications channel, with each receiver subsystem of said plurality of receiver subsystems including,a receiver antenna, coupled to the communications channel, for receiving the plurality of spread-spectrum signals and the multiplicity of fading spread-spectrum signals;

    a plurality of matched filters, coupled to said receiver antenna, having a plurality of impulse responses matched to the plurality of chip-sequence signals, respectively, for detecting the plurality of spread-spectrum signals and the multiplicity of fading spread-spectrum signals, as a plurality of detected spread-spectrum signals and a multiplicity of detected-fading spread-spectrum signals, respectively;

    a plurality of RAKE and space-diversity combiners, coupled to said plurality of matched filters, with a first RAKE and space-diversity combiner coupled to each matched filter having an impulse response matched to a first chip-sequence signal, and with respective RAKE and space-diversity combiners coupled to respective matched filters having impulse responses matched to respective chip-sequence signals, for combining, for a respective chip-sequence signal, the plurality of detected spread-spectrum signals and the multiplicity of detected-fading spread-spectrum signals from said plurality of matched filters, thereby generating a plurality of combined signals and a plurality of signal amplitudes, respectively, with a first combined signal from the first RAKE and space-diversity combiner, and with respective combined signals from respective RAKE and space-diversity combiners;

    a multiplexer, coupled to said plurality of RAKE and space diversity combiners, for multiplexing the plurality of combined signals, thereby generating a multiplexed signal;

    a de-interleaver, coupled to said multiplexer, for de-interleaving the multiplexed signal from said multiplexer, thereby generating a de-interleaved signal; and

    a decoder, coupled to said de-interleaver, for decoding the de-interleaved signal.

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