Receiver with Orthogonal Beam Forming Technique

• US 20120063550A1
• Filed: 11/22/2010
• Published: 03/15/2012
• Est. Priority Date: 09/09/2010
• Status: Active Grant

• Current Assignee: Spatial Digital Systems Inc
• Original Assignee: Spatial Digital Systems Inc
• Inventors: Chang, Donald C. D., Sun, Yulan, Lu, Frank
• Granted Patent: US 9,252,799 B2
• Time in Patent Office: Days
• US Class Current: 375/340
• CPC Class Codes: H03M 1/002 Provisions or arrangements for saving power, e.g. by allowing a sleep mode, using lower supply voltage for downstream stages, using multiple clock domains or by selectively turning on stages when needed
• CPC Class Codes: H03M 1/0641 the dither being a random signal
• CPC Class Codes: H03M 1/08 of noise H03M1/0617 takes precedence
• CPC Class Codes: H03M 1/12 Analogue/digital converters H03M1/001 – H03M1/10 take precedence
• CPC Class Codes: H03M 1/1205 Multiplexed conversion systems
• CPC Class Codes: H03M 1/1215 using time-division multiplexing
• CPC Class Codes: H03M 1/188 Multi-path, i.e. having a separate analogue/digital converter for each possible range
• CPC Class Codes: H03M 1/20 Increasing resolution using an n bit system to obtain n + m bits
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence
• CPC Class Codes: H04B 1/123 using adaptive balancing or compensation means adaptive filter circuits and algorithms H03H
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04L 27/06 Demodulator circuits; Receiver circuits
• CPC Class Codes: H05K 999/99 dummy group

Abstract

A receiver with orthogonal beam forming technique is achieved that is capable of differentiating different signal components within the received composite signal. An adaptive processor is used to eliminate the signal component whose phase information is known or can be calculated. The phase information of the major component of a signal can be easily acquired by using a limiter. The phase information of other signal components can be acquired by their direction information and other characteristics, such as modulation scheme, etc. Multiple orthogonal beams can be formed by eliminating one unwanted signal component each time by the adaptive processor until all unwanted signal is eliminated. Thus, a composite signal from multiple sources can be broken down into their component signals.

Claims

1. An adaptive receiver capable of forming multiple orthogonal beams, with the present receiver comprising:

an antenna array system comprised of a plurality of elements,

a radio frequency signal conditioning unit,

a digital signal processing unit,

a memory element adapted to store digital calibration data comprising beam weighting vectors associated with said antenna elements,

wherein the aggregate received radio signals are converted to a useful format by the conditioning unit, then adaptively differentiated and separated into constituent signals by the signal processor based on differing signal strength and directionality.

2. The signal conditioning unit of claim 1, wherein the signal conditioning unit connected to the outputs of the antenna system, comprises

a plurality of low noise amplifiers,

a frequency down-conversion portion connected to outputs of the low noise amplifiers,

a digitizing portion connected to the outputs of the frequency down-conversion portion.

3. The frequency down-conversion portion of claim 2, wherein the frequency down-conversion portion comprises a plurality of frequency down-converters.

4. The digitizing portion of claim 2, wherein the digitizing portion comprises a plurality of analog-to-digital converters.

5. The digital signal processing unit of claim 1, wherein the processor adaptively separates and processes radio signals from multiple sources, comprises

a plurality of weighting processors,

a plurality of adaptive processors,

a plurality of electronic limiters which convert zero and positive signal sample into ‘

1’ and

convert negative signal sample into ‘

−

1’

,

a plurality of optimization loops which utilize adaptive algorithms to adaptively minimize the correlation between the optimized signal and unwanted signal component,

a phase alignment module to align the phase of input signal with the original phase on each channel which can be acquired by knowing directional information and modulation method of signal.

6. The digital signal processing unit of claim 5, wherein the composite input signal from said antenna array is digitized, amplified and frequency down-converted in the signal conditioning unit.

7. The digital signal processing unit of claim 5, wherein the adaptive processor is adapted to apply the beam weight vectors to the frequency down-converted signals to eliminate the signal component whose phase information is known or can be acquired.

8. The digital signal processing unit of claim 5, wherein said processor is further adapted to continually update beam weight vectors via running through said optimization loops until the desired output is achieved.

9. The adaptive receiver of claim 1, wherein the direction of arrival component of the received signal is used to approximate the phase information which is used by said adaptive processor to eliminate the direction of arrival component from said signal.

10. The adaptive receiver of claim 1, wherein other characteristics such as modulation of a signal component is used to approximate the phase information which is used by said adaptive processor to eliminate the component from said received signal.

11. The adaptive receiver of claim 1, wherein at least one orthogonal beam is formed by eliminating one unwanted signal component at each time until all unwanted components have been eliminated by said processor.