Automatic gain control and filtering techniques for use in on-channel repeater

• US 7,911,985 B2
• Filed: 03/03/2008
• Issued: 03/22/2011
• Est. Priority Date: 03/02/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Proctor, James A. Jr., Otto, James C., Gainey, Kenneth M.
• Primary Examiner(s): Qureshi; Afsar M.
• Application Number:
  US12/041,617
• Publication Number:
  US 20080225758A1
• Time in Patent Office: 1,114 Days
• Field of Search: 370272-403, 370400-406, 375211-233, 455 111- 25, 455/63.1, 455/67.13, 455/67.11, 455/562.1
• US Class Current: 370/279
• 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 having an automatic gain control 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 where gain between the uplink and downlink channels can be controlled according to one or more filter bank automatic gain control 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 cancellation 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 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 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 Third Generation (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 one of a 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 cancellation deploying automatic gain control operations in a digital repeater environment comprising:

receiving n blocks of i bins of data for an uplink channel and downlink channel in parallel;

determining total isolation of the system for block n at each bin i;

determining total allowable gain for each bin i from the total isolation;

determining estimate gain for each bin i;

identifying the minimum level of gain for each bin i among available gain values and storing the minimum gain value; and

producing an automatic gain control and filtered array for the uplink and downlink by multiplying the identified minimum gain level with the bin i of the digital filter.

12. The method as recited in claim 11, further comprising multiplying the bin i of the automatic gain control and filtered array with bin i of the uplink and downlink data blocks.

13. The method as recited in claim 11, further comprising performing the steps of the method of claim 11 across one or more frequency channels.

14. The method as recited in claim 13, further comprising performing the steps of the method of claim 11 across bin i of one or more frequency channels.

15. The method as recited in claim 11, further comprising comparing selected gain levels comprising estimate gain, maximum gain, and allowable gain to identify the minimum gain level for each bin i.

16. The method as recited in claim 11, further comprising identifying the minimum gain level between the uplink channel and the downlink channel.

17. A computer readable storage medium having stored thereon a set of instructions, which, when executed by a machine, cause the machine to perform acts, the acts comprising:

receiving n blocks of i bins of data for an uplink channel and downlink channel in parallel;

determining total isolation of the system for block n at each bin

determining total allowable gain for each bin i from the total isolation;

determining estimate gain for each bin i;

identifying the minimum level of gain for each bin i among available gain values and storing the minimum gain value; and

producing an automatic gain control and filtered array for the uplink and downlink by multiplying the identified minimum gain level with the bin i of the digital filter.

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

receiving n blocks of i bins of data for an uplink channel and downlink channel in parallel;

determining total isolation of the system for block n at each bin idetermining total allowable gain for each bin i from the total isolation;

determining estimate gain for each bin i;

identifying the minimum level of gain for each bin i among available gain values and storing the minimum gain value; and

producing an automatic gain control and filtered array for the uplink and downlink by multiplying the identified minimum gain level with the bin i of the digital filter.

19. A system that facilitates feedback loop cancellation in a repeater environment comprising elements configured to:

receive n blocks of i bins of data for an uplink channel and downlink channel in parallel;

determine total isolation of the system for block n at each bin i;

determine total allowable gain for each bin i from the total isolation;

determine estimate gain for each bin i;

identify the minimum level of gain for each bin i among available gain values and storing the minimum gain value; and

produce an automatic gain control and filtered array for the uplink and downlink by multiplying the identified minimum gain level with the bin i of the digital filter.

20. A repeater for a wireless communication network, the repeater operative to provide feedback cancellation 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, wherein the means for performing filter bank operations is operative to perform automatic gain control calculations across one or more frequency channels; and

means for performing one or more correlation operations for generating weights for use in signal cancellation and increasing isolation.