Method and apparatus for an adaptive filter architecture

• US 8,681,844 B2
• Filed: 09/14/2012
• Issued: 03/25/2014
• Est. Priority Date: 11/11/2008
• Status: Active Grant

• Current Assignee: ISCO International LLC
• Original Assignee: ISCO International Inc.
• Inventors: Abdelmonem, Amr, Cordone, Sean S.
• Primary Examiner(s): Liu, Shuwang
• Assistant Examiner(s): Tayong, Helene
• Application Number:
  US13/617,754
• Publication Number:
  US 20130010852A1
• Time in Patent Office: 557 Days
• Field of Search: 375/224, 375/148, 375/346, 375/350, 455/296, 455/278, 455/306, 370/335, 370/252
• US Class Current: 375/224
• 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 identifying a spectral region in a radio frequency spectrum, determining a signal strength of the spectral region, determining a correlation factor by correlating the signal strength of the spectral region, detecting according to the correlation factor interference in the spectral region, generating coefficient data to substantially suppress the interference in the spectral region, configuring a filter according to the coefficient data to substantially suppress the interference in the spectral region and produce a digital filtered signal, and transmitting the digital filtered signal to a base station. Other embodiments are disclosed.

Claims

1. A method, comprising:

scanning, by a device, a radio frequency spectrum;

identifying, by the device, an available frequency band in the radio frequency spectrum;

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

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

determining, by the device, 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 device, from the correlation factor a narrowband channel of the plurality of narrowband channels that contains narrowband interference;

generating, by the device, tuning coefficient data to substantially suppress the narrowband interference in the narrowband channel;

configuring, by the device, a filter according to the tuning coefficient data to substantially suppress the narrowband interference in the narrowband channel and produce a digital filtered signal; and

transmitting, by the device, the digital filtered signal to a base station.

2. The method of claim 1, wherein the digital filtered signal is formatted for transmission according to a Gigabit Ethernet protocol.

3. The method of claim 1, wherein the digital filtered signal is formatted for transmission according to an Open Base Station Architecture Initiative (OBSAI) protocol.

4. The method of claim 1, wherein the digital filtered signal is formatted for transmission according to a Common Public Radio Interface (CPRI) protocol.

5. The method of claim 1, wherein configuring the filter comprises tuning the filter to a filter frequency and a filter bandwidth according to the tuning coefficient data, and wherein the filter comprises a plurality of filter elements, and wherein the plurality of filter elements are arranged in parallel, or in 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 base station is a cellular base station.

8. The method of claim 1, wherein the method is performed by the device communicatively coupled to the base station.

9. The method of claim 8, wherein the device is located in the base station.

10. A device, comprising:

a filter apparatus; and

a circuit coupled to the filter apparatus, wherein execution of instructions by the circuit cause the circuit to perform operations comprising;

identifying a spectral region in a radio frequency spectrum;

selecting portions of the spectral region for engaging in a communication session independent of there being interference in the portions of the spectral region;

determining a signal strength for a plurality of channels corresponding to the portions of the spectral region;

determining a correlation factor by correlating the signal strength for each of the plurality of channels;

identifying from the correlation factor a channel of the plurality of channels experiencing interference;

generating coefficient data to substantially suppress the interference in the channel;

configuring the filter apparatus according to the coefficient data to substantially suppress the interference in the channel and produce a digital filtered signal; and

transmitting the digital filtered signal to a base station.

11. The device of claim 10, wherein the digital filtered signal is formatted for transmission according to one of a Gigabit Ethernet protocol, an Open Base Station Architecture Initiative (OBSAI) protocol, or a Common Public Radio Interface (CPRI) protocol.

12. The device of claim 10, wherein configuring the filter apparatus comprises tuning the filter to a filter frequency and a filter bandwidth according to the coefficient data.

13. The device of claim 10, wherein the filter apparatus comprises a plurality of filter elements.

14. The device of claim 13, wherein the plurality of filter elements are arranged in a parallel configuration.

15. The device of claim 13, wherein the plurality of filter elements are arranged in a cascaded configuration.

16. The device of claim 10, wherein the base station is a cellular base station, and wherein the device is communicatively coupled to the base station.

17. The device of claim 10, wherein the device is located in the base station.

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

identifying a spectral region in a radio frequency spectrum;

determining a signal strength of the spectral region;

determining a correlation factor by correlating the signal strength of the spectral region;

detecting according to the correlation factor interference in the spectral region;

generating coefficient data to substantially suppress the interference in the spectral region, wherein the coefficient data corresponds to at least one of notch frequencies, a bandpass frequency or a bandwidth;

configuring a filter according to the coefficient data to substantially suppress the interference in the spectral region and produce a digital filtered signal, wherein the configuring of the filter includes activating at least one target filter of a group of target filters, wherein the group of target filters includes at least one infinite impulse response filter or finite impulse response filter; and

transmitting the digital filtered signal to a base station.

19. The storage device of claim 18, wherein the circuit further performs operations comprising formatting the digital filtered signal according to one of a Gigabit Ethernet protocol, an Open Base Station Architecture Initiative (OBSAI) protocol, or a Common Public Radio Interface (CPRI) protocol.

20. The storage device of claim 18, wherein the circuit is located in the base station and wherein the operations further comprise selecting the spectral region for engaging in a communication session independent of there being interference in the spectral region.