Lan Xu

US Patent:

7856067, Dec 21, 2010

Filed:

Apr 4, 2007

Appl. No.:

11/732630

Inventors:

Charles C. Wang - Arcadia CA, US
Lan Xu - Cerritos CA, US
Samuel Lim - Los Angeles CA, US

Assignee:

The Aerospace Corporation - El Segundo CA

International Classification:

H04L 5/12
H04L 23/02

US Classification:

375261, 375265, 375241

Abstract:

Hierarchical modulation preferably uses a 16-ary quadrature amplitude modulation (QAM) modulator with a convolutional encoder that combine to effectively provide unequal protection to two different segments of streaming input data, with improved power efficiency with the same bandwidth efficiency, by encoding the first segment as coded data as LSBs as the second segment remains uncoded as uncoded MSBs, with the MSBs used for QAM constellation modest reliability interquadrant demodulation and detection, and with the LSBs used for low reliability intraquadrant detection, but with the LSBs subject to convolutional encoding and decoding rendering the LSBs with high reliability detection, such that, the two segments have unequal coding and modulation for providing unequal levels of reliability detection.

US Patent:

8614940, Dec 24, 2013

Filed:

Nov 14, 2012

Appl. No.:

13/676645

Inventors:

Christopher Joseph Clark - Hermosa Beach CA, US
Samuel Joseph Curry - Redondo Beach CA, US
Lan Xu - Cerritos CA, US

Assignee:

The Aerospace Corporation - El Segundo CA

International Classification:

H04J 11/00

US Classification:

370210, 370536, 370542

Abstract:

Under one aspect of the present invention, a system for processing a group of signals and interference includes (a) an analog-to-digital (A/D) converter for digitizing the group of signals and the interference; (b) a Fourier transform circuit for obtaining a Fourier transform of the digitized group of signals and the interference and to provide as output spectral bins, at least one of which contains the interference; (c) a power analysis circuit for comparing the collective power level of the spectral bins to a predetermined threshold, and if the collective power level exceeds the predetermined threshold, and for excising at least one bin that contains the interference; and (d) an inverse Fourier transform circuit for obtaining an inverse Fourier transform of the remaining spectral bins and outputting a digitized group of signals less the interference in any excised spectral bin.

US Patent:

20140133328, May 15, 2014

Filed:

Aug 26, 2013

Appl. No.:

14/010390

Inventors:

- EL SEGUNDO CA, US
Christopher Joseph Clark - Hermosa Beach CA, US
Samuel Joseph Curry - Redondo Beach CA, US
Lan Xu - Cerritos CA, US

Assignee:

THE AEROSPACE CORPORATION - EL SEGUNDO CA

International Classification:

H04B 15/00

US Classification:

370252

Abstract:

Under one aspect of the present invention, a system for processing a group of signals and interference includes (a) an analog-to-digital (A/D) converter for digitizing the group of signals and the interference; (b) a Fourier transform circuit for obtaining a Fourier transform of the digitized group of signals and the interference and to provide as output spectral bins, at least one of which contains the interference; (c) a power analysis circuit for comparing the collective power level of the spectral bins to a predetermined threshold, and if the collective power level exceeds the predetermined threshold, and for excising at least one bin that contains the interference; and (d) an inverse Fourier transform circuit for obtaining an inverse Fourier transform of the remaining spectral bins and outputting a digitized group of signals less the interference in any excised spectral bin.