Granted Patent B2

US 8,787,474 · App. 13/685,010 · Granted Jul 22, 2014

Abstract

Claims (9)

1. A method for generating a signal with a random low peak to average power ratio waveform for an orthogonal frequency division multiplexing system, the method comprising:

obtaining a complex vector and dividing the complex vector into a first vector section and a second vector section, wherein an inverse fast Fourier transform result of the complex vector has a low peak to average power ratio real waveform and the complex vector includes a plurality of elements, wherein each of the first and second vector sections includes half of the elements of the complex vector and the second vector section is the conjugate mirror of the first vector section;

processing the complex vector to generate a processed complex vector, wherein processing the complex vector includes randomly cyclically shifting the first vector section and the second vector section to generate a cyclically shifted first vector section and a cyclically shifted second vector section, wherein the cyclically shifted second vector section is the conjugate mirror of the cyclically shifted first vector section;

wherein randomly cyclically shifting the first vector section and the second vector section includes cyclically shifting the first vector section an amount in a direction using a linear feedback shift register to generate the cyclically shifted first vector section and cyclically shifting the second vector section in the opposite direction by the same amount to generate the cyclically shifted second vector section;

and performing an inverse fast Fourier transform on the processed complex vector to generate a signal with a random low peak to average power ratio waveform.

2. The method of claim 1 further comprising multiplying the complex vector by an imaginary unit before performing the inverse fast Fourier transform on the processed complex vector.

3. The method of claim 2 , wherein the signal with the low peak to average power ratio waveform is a purely imaginary signal.

4. The method of claim 1 further comprising multiplying the processed complex vector by a sum of a square root of one half and a product of the square root of one half and an imaginary unit before performing the inverse fast Fourier transform on the processed complex vector.

5. The method of claim 4 , wherein the signal with the low peak to average power ratio waveform includes an in phase component and a quadrature component and the in phase component is equal to the quadrature component.

Assignments (6)