US 9,083,595 B2 · Signal modulation method resistant to echo reflections and frequency offsets

Abstract

A method of modulating communications signals, such as optical fiber, wired electronic, or wireless signals in a manner that facilitates automatic correction for the signal distortion effects of echoes and frequency shifts, while still allowing high rates of data transmission. Data symbols intended for transmission are distributed into N×N matrices, and used to weigh or modulate a family of cyclically time shifted and cyclically frequency shifted waveforms. Although these waveforms may then be distorted during transmission, their basic cyclic time and frequency repeating structure facilitates use of improved receivers with deconvolution devices that can utilize the repeating patterns to correct for these distortions. The various waveforms may be sent in N time blocks at various time spacing and frequency spacing combinations in a manner that can allow interleaving of blocks from different transmitters. Applications to channel sounding/characterization, system optimization, and also radar are also discussed.

Claims20

Dependent claims

A method of transferring a plurality of data symbols using a signal modulated to allow automatic compensation for the signal impairment effects of echo reflections and frequency offsets, said method comprising:

distributing said plurality of data symbols into one or more N×N symbol matrices;
using said one or more N×N symbol matrices to control the signal modulation of a transmitter, wherein for each said N×N symbol matrix, said transmitter uses each data symbol to weight N waveforms, selected from a N2 sized set of all permutations of N cyclically time shifted and N cyclically frequency shifted waveforms determined according to an encoding matrix U, thus producing N symbol-weighted cyclically time shifted and cyclically frequency shifted waveforms for each data symbol;
wherein said encoding matrix U is chosen to be an N×N unitary matrix that has a corresponding inverse decoding matrix UH;
for each data symbol in said N×N symbol matrix, summing the N symbol-weighted cyclically time shifted and cyclically frequency shifted waveforms, producing N2 summation-symbol-weighted cyclically time shifted and cyclically frequency shifted waveforms;
and transmitting said N2 summation-symbol-weighted cyclically time shifted and cyclically frequency shifted waveforms, structured as N composite waveforms, over any combination of N time blocks or frequency blocks.

2 more elements

A method of transferring a plurality of data symbols using a wireless signal modulated to allow automatic compensation for the wireless signal impairment effects of echo reflections and frequency offsets, said method comprising:

Distributing said plurality of data symbols into one or more N×N symbol matrices;
Using said one or more N×N symbol matrices to control the wireless signal modulation of a wireless transmitter, wherein for each said N×N symbol matrix, said wireless transmitter uses each data symbol to weight N waveforms, selected from a N2 sized set of all permutations of N cyclically time shifted and N cyclically frequency shifted waveforms determined according to an encoding matrix U, thus producing N symbol-weighted cyclically time shifted and cyclically frequency shifted waveforms for each data symbol;
Wherein said encoding matrix U is chosen to be an N×N unitary matrix that has a corresponding inverse decoding matrix UH;
For each data symbol in said N×N symbol matrix, summing the N symbol-weighted cyclically time shifted and cyclically frequency shifted waveforms, producing N2 summation-symbol-weighted cyclically time shifted and cyclically frequency shifted waveforms;
And transmitting said N2 summation-symbol-weighted cyclically time shifted and cyclically frequency shifted waveforms, structured as N composite waveforms, over any combination of N time blocks or frequency blocks.

2 more elements

Dependencies are inferred from the claim text.

Signal modulation method resistant to echo reflections and frequency offsets

Life of this patent

Signal modulation method resistant to echo reflections and frequency offsets

Life of this patent

Abstract

Claims20