Blind selected mapping for peak-to-average power ratio reduction in OFDM with PSK input

Communication apparatus, comprising:

• (1) a transmitter comprising:
• an amplitude lookup table comprising a plurality of distinct amplitude functions;
• a plurality of amplitude tagging processes for processing a constant modulus frequency domain signal using the distinct amplitude functions to generate a plurality of different sub-channel signals;
• a phase lookup table comprising a plurality of pseudo-random phase sequences;
• a plurality of phase rotation processes for rotating phases of the sub-channel signals using the respective pseudo-random phase sequences;
• a plurality of inverse discrete Fourier transforms for inverse Fourier transforming the respective sub-channel signals into the time domain;
• a plurality of upsampling processes for upsampling the inverse Fourier transformed sub-channel signals;
• a process for calculating the crest factor for each of the upsampled sub-channel signals to select the sub-channel signal having the minimum crest factor;
• a digital-to-analog converter for converting the selected sub-channel signal having the minimum crest factor to an analog signal for transmission over a communication channel;
• and
• a power amplifier for amplifying the analog signal for transmission;
• and
• (2) a receiver comprising:
• an analog-to-digital converter for digitizing the received analog signal;
• a discrete Fourier transform for transforming the digitized received signal into the frequency domain;
• an amplitude tag detector for detecting the amplitude tag in each sub-channel signal by matching the estimated amplitude function with the distinct amplitude function templates;
• a phase lookup table for selecting a phase de-rotation sequence associated with the detected amplitude tag;
• a phase de-rotation process for de-rotating the phases of the Fourier transformed signal using the phase de-rotation sequence from the phase lookup table;
• and
• a symbol detector for detecting the constant modulus frequency domain signal transmitted by the transmitter.

A method comprising:

• processing a constant modulus frequency domain source signal using a plurality of unique amplitude tags and a plurality of invertible transforms to transform the source signal into a plurality of unique sub-channel signals;
• upsampling the inverse Fourier transformed sub-channel signals;
• calculating the crest factor for each of the upsampled sub-channel signals and selecting the sub-channel signal having the minimum crest factor;
• transmitting an analog version of the selected sub-channel signal over a communication channel;
• digitizing the received signal;
• Fourier transforming the digitized received signal into the frequency domain;
• detecting the unique amplitude tag associated with the digitized received signal;
• identifying the invertible transform associated with the detected amplitude tag;
• and
• detecting the constant modulus frequency domain source signal transmitted by the transmitter.