Charles D. Murphy

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Orthogonal frequency-division multiplexing is a multiple-access technique with modulation and demodulation implemented by an inverse discrete Fourier transform (DFT) and a DFT, respectively. In a downlink (uplink) environment, an individual receiver (transmitter) may only use a small number of subchannels at any given time, in which case it does not make(More)
I N T R O D U C T I O N When bandwidth is limited and data rates are high, digital communications systems employ large constellations of closely-packed symbols. M-ary QAM constellations with M = 64, 128, 256, 512, and 1024 satisfy the requirement of sending 6, 7, 8, 9, or 10 bits per symbol, assuming that the transmitted symbols are equiprobable and(More)
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