Patent ID: 7668266

Claim:
Communication apparatus, comprising: a transmitter comprising: a plurality of invertible differentiating transforms for processing a frequency domain signal to generate a plurality of different sub-channel signals; a plurality of tagging processes for uniquely identifying each of the sub-channel signals by way of a unique tag embedded in the respective sub-channel signal; a plurality of inverse discrete Fourier transforms for respectively inverse Fourier transforming the 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 and for selecting the sub-channel having the minimum crest factor; a digital-to-analog (D/A) converter for converting the selected sub-channel signal having the minimum crest factor to an analog signal for transmission; a power amplifier for amplifying the analog signal for transmission over a communication channel; a plurality of pilot shifting processes for processing a frequency domain signal to generate a plurality of different sub-channel signals having shifted pilot tones in each sub-channel signal that are shifted by a unique delay; a lookup table comprising a plurality of pseudo-random phase sequences; and a plurality of phase rotation processes for rotating phases of the sub-channel signals using the respective pseudo-random phase sequences to generate the sub-channel signals; and a receiver comprising: an analog-to-digital converter for digitizing a received analog signal; a discrete Fourier transform for transforming the digitized received signal into the frequency domain; a tag detector for detecting the unique tag embedded in the received signal and identifying the invertible differentiating transform associated with the detected tag; an inverse process for processing the received signal using an inverse transform of the identified differentiating transform; a channel estimator for estimating the communication channel; a symbol detector for compensating for distortion associated with the communication channel and for detecting the frequency domain signal transmitted by the transmitter; a peak detector for detecting the power peaks in the transformed signal to identify the shift of the pilot tone; a lookup table for selecting an inverse phase rotation sequence associated with the detected shift of the pilot tone; and a phase rotation process for rotating the transformed signal using the inverse phase sequence from the lookup table.