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Communication system for plural data streams

  • US 5,892,879 A
  • Filed: 09/27/1993
  • Issued: 04/06/1999
  • Est. Priority Date: 03/26/1992
  • Status: Expired due to Term
First Claim
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1. A communication system comprising:

  • a transmitter including;

    a signal input means for receiving an input signal and for dividing said input signal into a first data stream having n values and a second data stream,a modulator means for producing m (m≧

    4) signal points in a constellation expressed at least in a polar coordinate system (r, θ

    ) by modulating a carrier wave using said first data stream of n values and said second data stream, said modulator means dividing said m signal points into n signal point groups, assigning said n values of the first data stream to said n signal point groups, assigning m/n signal points in each signal point group to m/n values of said second data stream, allocating said m signal points at uneven intervals so that a distance between said m/n signal points in the same signal point group is reduced compared with a uniform interval obtained according to a uniform signal point allocation, anda transmitting means for transmitting a modulated signal modulated by said modulator means; and

    a receiver including;

    a receiver input means for reception of said modulated signal transmitted from the transmitter,a demodulating means for demodulating said modulated signal into demodulation signal representing P signal points in a constellation expressed at least in the polar coordinate system (r, θ

    ), by dividing said P signal points into n signal point groups, where P and n are integers, assigning said n signal point groups to n values to demodulate the first data stream of n values, and assigning P/n signal points in the same signal point group to P/n values to demodulate the second data stream of P/n values; and

    an output means for outputting said demodulation signal demodulated by said demodulating means, in such a manner that, when an error rate of said modulated signal is higher than a predetermined level, only said first data stream is output while said second data stream is cancelled.

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