Method and apparatus for an adaptive filter architecture

• US 8,774,335 B2
• Filed: 09/14/2012
• Issued: 07/08/2014
• Est. Priority Date: 11/11/2008
• Status: Active Grant

• Current Assignee: ISCO International LLC
• Original Assignee: ISCO International LLC
• Inventors: Abdelmonem, Amr, Cordone, Sean S.
• Primary Examiner(s): Liu, Shuwang
• Assistant Examiner(s): TAYONG, HELENE E
• Application Number:
  US13/617,692
• Publication Number:
  US 20130017850A1
• Time in Patent Office: 662 Days
• Field of Search: 375/350, 455/501
• US Class Current: 375/350
• CPC Class Codes: H04B 1/1036 with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters H04B1/123 takes precedence; filter circuits H03H
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/7093 Matched filter type
• CPC Class Codes: H04B 1/7103 the interference being multiple access interference
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04B 2001/1072 by tuning the receiver frequency
• CPC Class Codes: H04J 11/0023 Interference mitigation or co-ordination direct sequence spread spectrum [DSSS] systems H04B1/7097; frequency hopping H04B1/713; allocation criteria for ingress interference avoidance H04L5/0062; frequency allocation criteria for requirements on out-of-channel emissions H04L5/0066; arrangements for removing intersymbol interference or baseband equalisers H04L25/03006; peak power aspects in multicarrier modulation H04L27/2614; power management H04W52/00; traffic scheduling H04W72/54, H04W72/541
• CPC Class Codes: H04L 27/0006 Assessment of spectral gaps suitable for allocating digitally modulated signals, e.g. for carrier allocation in cognitive radio for spectrum sharing between different networks H04W16/14
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/542 using measured or perceived quality
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: H04W 88/10 adapted for operation in multiple networks, e.g. multi-mode access points

Abstract

A system that incorporates teachings of the subject disclosure may include, for example, a method for scanning a radio frequency spectrum for an available frequency band, selecting an available frequency band in the radio frequency spectrum even if the available frequency band is affected by radio frequency interference, measuring a signal strength in portions of the available frequency band, correlating the signal strength of each portion to generate a correlation factor, detecting radio frequency interference in the available frequency band according to the correlation factor, and generating tuning coefficient data to cause the filter apparatus to substantially suppress the radio frequency interference in the available frequency band. Other embodiments are disclosed.

Claims

1. A method, comprising:

scanning, by a cognitive radio, a radio frequency spectrum;

identifying, by the cognitive radio, an available frequency band in the radio frequency spectrum, wherein a portion of the available frequency band is subject to undesirable radio frequency interference;

selecting, by the cognitive radio, the available frequency band for engaging in communications independent of there being interference in the available frequency band;

determining, by the cognitive radio, a signal strength for each of a plurality of narrowband channels in the available frequency band;

determining, by the cognitive radio, a correlation factor for at least a portion of the plurality of narrowband channels by correlating the signal strength for each of the plurality of narrowband channels;

identifying, by the cognitive radio, from the correlation factor a narrowband channel of the plurality of narrowband channels that contains narrowband interference; and

generating, by the cognitive radio, tuning coefficient data to substantially suppress the narrowband interference in the narrowband channel for communicating in the narrowband channel.

2. The method of claim 1, comprising configuring a filter according to the tuning coefficient data to substantially suppress the narrowband interference in the narrowband channel.

3. The method of claim 2, wherein configuring the filter comprises tuning the filter to a filter frequency and a filter bandwidth according to the tuning coefficient data.

4. The method of claim 2, wherein the filter comprises a plurality of filter elements.

5. The method of claim 4, wherein the plurality of filter elements are arranged in parallel, or a cascaded configuration.

6. The method of claim 1, wherein determining the correlation factor comprises repeating a determination of the signal strength for each of the plurality of narrowband channels in the available frequency band.

7. The method of claim 1, wherein the available frequency band is a wide frequency band.

8. The method of claim 1, wherein the cognitive radio is a mobile phone.

9. The method of claim 1, wherein the cognitive radio is a cellular base station.

10. A cognitive radio, comprising:

an antenna;

a filter apparatus;

a digital radio tuner;

a first signal sampler positioned between the antenna and the filter apparatus, the first signal sampler obtaining first information associated with input signals to the filter apparatus;

a second signal sampler positioned between the filter apparatus and the digital radio tuner, the second signal sampler obtaining second information associated with output signals from the filter apparatus; and

a circuit coupled to the filter apparatus and the first and second signal samplers, wherein execution of instructions by the circuit causes the circuit to perform operations comprising;

scanning a radio frequency spectrum for an available frequency band;

selecting an available frequency band in the radio frequency spectrum independent of there being interference in the available frequency band;

measuring a signal strength in portions of the available frequency band;

correlating the signal strength of each portion to generate a correlation factor;

detecting radio frequency interference in the available frequency band according to the correlation factor;

generating first tuning coefficient data to cause the filter apparatus to substantially suppress the radio frequency interference in the available frequency band, wherein the generating of the first tuning coefficient data is according to the first information received from the first signal sampler; and

generating second tuning coefficient data to cause the filter apparatus to be adjusted for the suppressing of the radio frequency interference in the available frequency band, wherein the generating of the second tuning coefficient data is according to the second information received from the second signal sampler.

11. The cognitive radio of claim 10, wherein the portions of the available frequency band comprise narrowband channels in the available frequency band and wherein the operations further comprise receiving, by the circuit, a master clock signal which facilitates synchronizing the circuit with the digital tuner, wherein the generating of the first and second tuning coefficient data are according to a schedule based on the synchronizing of the circuit with the digital tuner.

12. The cognitive radio of claim 11, wherein measuring the signal strength in the portions of the available frequency band comprises measuring the signal strength in the narrowband channels of the available frequency band, and wherein the master clock signal is received by the circuit from the digital tuner.

13. The cognitive radio of claim 11, wherein detecting the radio frequency interference comprises detecting the radio frequency interference in at least one of the narrowband channels.

14. The cognitive radio of claim 11, wherein the circuit comprises a field programmable gate array.

15. The cognitive radio of claim 14, wherein configuring the filter apparatus comprises tuning the filter apparatus to a filter frequency and a filter bandwidth according to the tuning coefficient data.

16. The cognitive radio of claim 10, wherein the instructions comprise computer instructions, wherein the circuit comprises a processor to execute the computer instructions, and wherein the operations further comprise receiving, by the circuit, scanning limitation information from the digital tuner, wherein the scanning of the radio frequency spectrum for the available frequency band is limited to a subset of an available radio frequency spectrum according to the scanning limitation information.

17. The cognitive radio of claim 10, wherein the available frequency band is a wideband frequency band, and wherein the cognitive radio is one of a portable communication device or a base station.

18. A storage device, comprising instructions, which when executed by a cognitive radio, cause the cognitive radio to perform operations comprising:

scanning an available frequency band in a radio frequency spectrum for initiating a communication session, wherein the available frequency band is affected by radio frequency interference;

selecting the available frequency band for engaging in communications independent of there being interference in the available frequency band;

correlating a signal strength of portions of the available frequency band to generate a correlation factor;

detecting radio frequency interference in the available frequency band according to the correlation factor; and

generating tuning coefficient data to substantially suppress the radio frequency interference in the available frequency band during the communication session.

19. The storage device of claim 18, wherein the operations further comprise measuring the signal strength in narrowband channels of the available frequency band.

20. The storage device of claim 18, wherein the operations further comprise configuring a filter according to the tuning coefficient data to substantially suppress the radio frequency interference in the available frequency band during the communication session.