Use of a Filterbank in an Adaptive On-Channel Repeater Utilizing Adaptive Antenna Arrays

• US 20080225930A1
• Filed: 03/03/2008
• Published: 09/18/2008
• Est. Priority Date: 03/02/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Otto, James C., Gainey, Kenneth M., Proctor, James A.
• Granted Patent: US 8,116,239 B2
• Time in Patent Office: Days
• US Class Current: 375/214
• CPC Class Codes: H04B 7/15542 Selecting at relay station its transmit and receive resources selection of wireless resources by user or terminal H04W72/02; arrangements affording multiple use of the transmission path by two-dimensional division of the resources H04L5/0003, or by allocating sub-channels H04L5/003
• CPC Class Codes: H04B 7/15571 by signal isolation, e.g. isolation by frequency or by antenna pattern, or by polarization
• CPC Class Codes: H04B 7/15585 by interference cancellation

Abstract

A repeater environment is provided operative to deploy a feedback cancellation loop that is adaptively coupled with an antenna array such that a selected metric can be derived by deploying a selected filter bank operative to process the signal on a bin by bin basis and the derived metric can be applied to the antenna array and feedback cancellation loop combination to improve signal integrity and amplification. In an illustrative implementation, an exemplary repeater environment comprises, a transmitter, a receiver, an equalized feedback cancellation loop circuitry comprising a filter bank, the cancellation loop being operatively coupled to an antenna array. In the illustrative implementation, the feedback cancellation loop can receive signals as input from a cooperating antenna array and provide output signals such as a feedback leakage signal to a cooperating antenna array.

Claims

1. A repeater for a wireless communication network, the repeater operative to provide feedback cancellation, the repeater comprising:

a calculation module configured to perform filter bank calculations for weights used by an equalizer, wherein N samples of the transmitter and/or receiver signal are stored as part of filter bank operations; and

an equalized feedback cancellation loop comprising a filter bank cooperating with the calculation module to generate weights derived from one or more correlation operations to provide signal cancelation and isolation.

2. The repeater as recited in claim 1, wherein N is greater than or equal to one.

3. The repeater as recited in claim 1, wherein the filter bank cancellation calculations comprise minimum mean squared error (MMSE) calculations.

4. The repeater as recited in claim 1, further comprising one or more fast Fourier transform (FFT) modules operative to convert an input signal to the repeater from the time domain to the frequency domain.

5. The repeater as recited in claim 4, further comprising one or more FFT modules operative to transform a conditioned frequency domain signal conditioned according to one or more filter bank operations to a time domain series.

6. The repeater as recited in claim 1, wherein the repeater is a Time Division Duplex repeater and the wireless communication network is one of a Wireless-Fidelity (Wi-Fi), and Worldwide Interoperability for Microwave Access (Wi-max) network.

7. The repeater as recited in claim 1, wherein the repeater is a Frequency Division Duplex repeater and the wireless communication network is one of a cellular, Global System for Mobile communications (GSM), Code Division Multiple Access (CDMA), and ThirdGeneration (3G) network.

8. The repeater as recited in claim 1, wherein the reception and/or transmission antennas comprise at least one of dipole antennas and patch antennas.

9. The repeater as recited in claim 1, wherein the calculation module comprises digital logic to manage, control, monitor, and direct the filter bank calculations.

10. The repeater as recited in claim 1, wherein the filter bank calculations are performed by executing a linear algebra algorithm comprising minimum mean squared error (MMSE) algorithm, maximum signal-to-noise ration algorithm, and linear constrained minimum variance algorithm.

11. A method to facilitate feedback loop cancelation in a digital repeater environment comprising:

receiving transmitter leakage signal and receive signal at M number of receivers;

zero-padding time samples to input to a fast Fourier transform (FFT) for each of the M number of receivers;

performing an FFT on the zero appended receive block;

applying a M number complex spatial weight array on the M number of receivers;

combining the weighted frequency bins into a composite signal;

producing a post cancellation receive frequency bin;

applying an inverse FFT on the N weighted transmit frequency bin arrays to produce N time domain series;

transmitting N number of transmit time domain series; and

receiving N number of repeater transmit signals at M number of receivers to form M number repeater transmit leakage signals summed with M number of received signals.

12. The method as recited in claim 11, further comprising storing Ns samples as M number of receiver time blocks from cooperating receivers.

13. The method as recited in claim 12, further comprising producing a post cancellation receive frequency bin using the composite signal.

14. The method as recited in claim 13, further comprising producing a post cancellation receive frequency bin using one or more closed form calculations.

15. The method as recited in claim 11, further comprising updating values for the feedback loop based on one or more selected values comprising time series of composite weighted receiver frequency bins, time series of post cancellation receive frequency bins, and the time series of delayed transmitter frequency bins.

16. The method as recited in claim 11, further comprising producing a filtered automatic gain control output frequency bin by multiplying coefficients by generated post cancellation receive frequency bins.

17. The method as recited in claim 11, further comprising calculating an updated automatic gain control and filter array by utilizing one or more of pre-correlation leakage frequency bin metric, residual leakage correlation frequency bin metric, power in frequency bin, power out frequency bin metric, and isolation margin per frequency bin metric to perform an automatic gain control calculation on a bin by bin basis.

18. The method as recited in claim 11, wherein a time series of AGC Filter frequency bin are multiplied by at least one coefficient derived from a correlation process and added or subtracted to the a composite receive frequency bin time series.

19. A computer readable medium having stored thereon computer executable instructions for performing at least the following acts:

receiving transmitter leakage signal and receive signal at M number of receivers;

zero-padding M number of receiver time series of Ns samples as input to a fast Fourier transform (FFT) for the M number of receivers;

performing an FFT on the zero appended receive block;

applying a M number complex spatial weight array on the M number of receivers;

combining the weighted frequency bins into a composite signal;

producing a post cancellation receive frequency bin;

applying an inverse FFT on the N weighted transmit frequency bin arrays to produce N time domain series;

transmitting N number of transmit time domain series; and

receiving N number of repeater transmit signals at M number of receivers to form M number repeater transmit leakage signals summed with M number of received signals.

20. A processor, comprising a memory having stored thereon computer executable instructions to cause the processor to performing at least the following acts:

receiving transmitter leakage signal and receive signal at M number of receivers;

zero-padding M number of receiver time series of Ns samples as input to a fast Fourier transform (FFT) the M number of receivers;

performing an FFT on the zero appended receive block;

applying a M number complex spatial weight array on the M number of receivers;

combining the weighted frequency bins into a composite signal;

producing a post cancellation receive frequency bin;

applying an inverse FFT on the N weighted transmit frequency bin arrays to produce N time domain series;

transmitting N number of transmit time domain series; and

receiving N number of repeater transmit signals at M number of receivers to form M number repeater transmit leakage signals summed with M number of received signals.

21. A system that facilitates feedback loop cancelation in a repeater environment comprising:

means for receiving transmitter leakage signal and receive signal at M number of receivers;

means for performing an FFT on the zero appended receive block;

means for applying a M number complex spatial weight array on the M number of receivers;

means for combining the weighted frequency bins into a composite signal;

means for producing a post cancellation receive frequency bin;

means for applying an inverse FFT on the N weighted transmit frequency bin arrays to produce N time domain series;

means for transmitting N number of transmit time domain series; and

means for receiving N number of repeater transmit signals at M number of receivers to form M number repeater transmit leakage signals summed with M number of received signals.

22. A repeater for a wireless communication network, the repeater operative to provide feedback cancellation, the repeater comprising:

means for performing filter bank calculations for weights used by an equalizer, wherein samples of the transmitter and/or receiver signal are stored as part of closed loop calculations and the input signal is transformed to the frequency domain for filter bank calculations, wherein the input signal is decomposed into narrow bands across one or more processing bins; and

means for generating weights for use in one or more correlation operations to provide signal cancelation and isolation.