Use of Adaptive Antenna Array in Conjunction with an On-Channel Repeater to Improve Signal Quality

• US 20080225931A1
• 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 8,619,837 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 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 one or more of selected metrics (e.g., composite metrics) comprising 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, beam forming operations, and pilot control and overhead channel control operations. 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

Claims

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

a metric module configured to perform calculations for weights used by the repeater, and to generate a composite metric derived from metric execution of one or more of an adaptive algorithm, beam forming, and filter bank approach; and

an adaptive antenna array cooperating with the metric module to condition signals as part of calculating the composite metric.

2. The repeater as recited in claim 1, further comprising pilot and overhead channel demodulators for use in one or more operations to allow for signal isolation and improvement in the quality of one or more of a pilot channel and overhead channel.

3. The repeater as recited in claim 1, wherein the filter bank approach calculation 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 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 Third Generation (3G) network.

8. The repeater as recited in claim 1, wherein the reception and/or transmission antennas comprise one or more 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 metric module 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 promote signal integrity in a digital repeater environment comprising:

producing pilot energy measurements representative using available correlation metrics;

measuring non-correlated energy values;

calculating the residual leakage metric;

determining the total transmitted power from the repeater;

calculating a metric that is a function of one or more of the pilot energy measurements, non-correlated energy values, residual leakage metric, and output power of the repeater to generate a composite metric; and

applying a steepest descent adaptive algorithm to modify the spatial weight settings to optimize the composite metric.

12. The method as recited in claim 11, further comprising producing a pilot energy measurement using one or more repeater values comprising a set of time series of one or more post cancellation receive frequency bins, time series of post cancellation receive signal associated with the desired carrier signal frequency channel.

13. The method as recited in claim 12, further comprising measuring the average interference as a correlation of one or more repeater values comprising a set of time series of one or more post cancellation receive frequency bins, time series of post cancellation receive signal associated with the desired carrier signal frequency channel and a cooperating wireless communication channel value to generate the average interference value, the average interference value described as the non-correlated energy of the wireless communication channel.

14. The method as recited in claim 13, further comprising processing a selected number of transmitter transmitted weighted repeater signals to determine the transmitted power output.

15. The method as recited in claim 11, further comprising summing the mean squared averages of array signals to generate the power output value.

16. The method as recited in claim 11, further comprising repeating the steps of the method of claim 11 across the input signal.

17. The method as recited in claim 11, further comprising selecting a number representative of the degree of misalignment between a selected channel value and the peak correlation.

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

producing pilot energy measurements;

measuring non-correlated energy values;

calculating the residual leakage metric;

determining the sum of the mean squared averages of an array of signals;

calculating a metric that is a function of one or more of the pilot energy measurements, non-correlated energy values, residual leakage metric, and output power of the repeater to generate a composite metric; and

applying a steepest descent adaptive algorithm to modify the spatial weight settings to optimize the composite metric.

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

producing pilot energy measurements representative using available correlation metrics;

measuring non-correlated energy values;

calculating the residual leakage metric;

determining the sum of the mean squared averages of an array of signals;

calculating a metric that is a function of one or more of the pilot energy measurements, non-correlated energy values, residual leakage metric, and output power of the repeater to generate a composite metric; and

applying a steepest descent adaptive algorithm to modify the spatial weight settings to optimize the composite metric.

20. A system that facilitates feedback loop cancellation 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 M zero appended receive block from M receivers to produce M sets of frequency bins;

means for applying M complex spatial weight arrays respectively to the M number of sets of frequency bins;

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 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.

21. A repeater for a wireless communication network, the repeater operative to provide repeater signal quality improvement comprising:

means for performing filter bank calculations for weights provided by a metric module, 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 cancellation, isolation, and signal quality improvement.

22. The method as recited in claim 21, wherein the signal quality improvement is a improvement in the ratio of the correlation signal power to the non correlated signal power.

23. The method as recited in claim 21, wherein the signal quality improvement is an increase in the receive signal strength of the desired signal.

24. The method as recited in claim 21, wherein the signal quality improvement is an improvement in the signal to noise ratio of the desired signal.