Interference reduction for multiple signals

• US 7,076,228 B1
• Filed: 03/30/2003
• Issued: 07/11/2006
• Est. Priority Date: 11/10/1999
• Status: Expired due to Term

• Current Assignee: Kenneth F. Rilling
• Original Assignee: Kenneth F. Rilling
• Inventors: Rilling, Kenneth F.
• Primary Examiner(s): Orgad, Edan
• Assistant Examiner(s): Rego, Dominic E.
• Application Number:
  US10/405,010
• Time in Patent Office: 1,199 Days
• Field of Search: 455/278.1, 455/279.1, 455/283, 455/129, 455/63.1, 455/114.2, 455/296, 342/368, 342/203, 342/421, 342/423, 342/434
• US Class Current: 455/278.1
• CPC Class Codes: H04B 1/10 Means associated with receiver for limiting or suppressing noise or interference
• CPC Class Codes: H04B 1/1081 Reduction of multipath noise by equalising H04B7/005
• CPC Class Codes: H04B 7/0848 Joint weighting
• CPC Class Codes: H04B 7/0851 using training sequences or error signal minimizing error signal H04B7/0854
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming
• CPC Class Codes: H04B 7/0862 receiver computing weights based on information from the transmitter
• CPC Class Codes: H04L 25/03019 adaptive, i.e. capable of adjustment during data reception
• CPC Class Codes: H04L 25/03025 using a two-tap delay line
• CPC Class Codes: H04L 25/03885 adaptive
• CPC Class Codes: H04L 27/38 Demodulator circuits; Receiver circuits

Abstract

The present invention reduces the degradation in performance of one or more radio signals that are co-transmitted with a first radio signal from the same transmitting antenna in the same frequency channel and received by the same antenna due to multipath or other shared interference, where the one or more radio signals can be separated from the first radio signal. All received signals are coupled to the same adaptive array or adaptive filter to reduce multipath or other shared interference of the first radio signal, which reduces multipath and other shared interference in the other radio signals before they are separated and processed by their respective receivers, or the individual radio signals are separated before the first signal enters the adaptive array or adaptive filter and each of the other signals coupled to an individual associated adaptive array or adaptive filter slave weighting network with weights slaved to the weights of the adaptive array or adaptive filter of the first signal to reduce the multipath and other shared interference in all the signals.

Claims

1. A method for using one adaptive array and plurality of antenna elements for reducing first multipath interference of first radio signal, second multipath interference of second radio signal and other interference, where said second radio signal has power much less than said first radio signal, each input of said adaptive array is coupled to separate one of said antenna elements, and said adaptive array is configured for said first radio signal, said method comprising the steps of:

a. forming separable signal combination of said first radio signal and said second radio signal in same frequency channel to generate transmit antenna input signal;

b. transmitting said transmit antenna input signal generated in step a. to generate transmitted radio signal;

c. receiving said transmitted radio signal generated in step b. with said antenna elements to generate antenna output signals;

d. reducing said first multipath interference, said second multipath interference and said other interference in representation of said antenna output signals generated in step c. with said adaptive array to generate an adaptive array output signal including representation of said first radio signal with reduced said first multipath interference, representation of said second radio signal with reduced said second multipath interference and reduced said other interference; and

e. separating said representation of second radio signal from said representation of first radio signal in said adaptive array output signal generated in step d. to generate a separated representation of said second radio signal.

2. A method as in claim 1, wherein said first radio signal is FM radio signal of IBOC system, said second radio signal is digital signal of said IBOC system.

3. A method as in claim 1, wherein said separable signal combination in step a. is an explicitly separable signal combination.

4. A method as in claim 1, wherein:

said second radio signal of said separable signal combination in step a. is implicitly separable from said first radio signal; and

separating said representation of second radio signal from said first radio signal includes suppressing said representation of first radio signal in said adaptive array output signal generated in step d.

5. A method for using one CMA adaptive array and plurality of antenna elements for reducing first multipath interference of FM radio signal, second multipath interference of second radio signal and other interference, said second radio signal has power much less than said FM radio signal, each input of said CMA adaptive array is coupled to separate one of said antenna elements, and said CMA adaptive array is configured for said FM radio signal, said method comprising the steps of:

a. forming explicitly separable signal combination of said second radio signal from said FM radio signal in same frequency channel to generate transmit antenna input signal;

b. transmitting said transmit antenna input signal generated in step a. to generate transmitted radio signal;

c. receiving said transmitted radio signal generated in step b. with said antenna elements to generate antenna output signals;

d. reducing said first multipath interference, said second multipath interference and said other interference in representation of said antenna output signals generated in step c. with said CMA adaptive array to generate an CMA adaptive array output signal including representation of said FM radio signal with reduced said first multipath interference, representation of said second radio signal with reduced said second multipath interference and reduced said other interference; and

e. separating said representation of second radio signal from said representation of FM radio signal in said CMA adaptive array output signal generated in step d. to generate a separated representation of said second radio signal.

6. A method for using one adaptive array with weights, slave weight network with slave weights and plurality of antenna elements for reducing first multipath interference of first radio signal, second multipath interference of said second radio signal and other interference, where each input of said adaptive array and each corresponding input of said slave weight network are coupled to separate associated one of said antenna elements, said slave weight network output is coupled to receiver for second radio signal, and said adaptive array is configured for said first radio signal, said method comprising the steps of:

a. forming signal combination of explicitly separable said first radio signal from said second radio signal and implicitly separable said second radio signal from said first radio signal in same frequency channel to generate transmit antenna input signal;

b. transmitting said transmit antenna input signal generated in step a. to generate transmitted radio signal;

c. receiving said transmitted radio signal generated in step b. with said antenna elements to generate antenna output signals;

d. separating first representation of said first radio signal from first representation of said second radio signal for representation of each one of said antenna output signals generate in step c. to generate separate first radio signal;

e. reducing said first multipath interference and associated said other interference in all said separate first radio signals generated in step d. with said adaptive array to generate an adaptive array output signal including second representation of said first radio signal with reduced said first multipath interference and reduced associated other interference by adjusting said weights and to generate associated slave weight signals from said weights;

f. reducing said first multipath interference said second multipath interference and said associated other interference in said representation of said antenna output signals generated in step c. with said slave weight network to generate an slave weight network output signal including second representation of said second radio signal with reduced said second multipath interference and reduced associated said other interference by applying said slave weight signals generated in step e. to associated said slave weights; and

g. suppressing said second representation of first radio signal in said slave weight network output signal generated in step f. with said receiver.

7. A method for using one adaptive array with weights, slave weight network with slave weights and plurality of antenna elements for reducing first multipath interference of first radio signal, second multipath interference of second radio signal and other interference, where each input of said adaptive array and each corresponding input of said slave weight network are coupled to separate one of said antenna elements, and said adaptive array is configured for said first radio signal, said method comprising the steps of:

a. forming signal combination of implicitly separable said first radio signal from said second radio signal and explicitly separable said second radio signal from said first radio signal in same frequency channel to generate transmit antenna input signal;

b. transmitting said transmit antenna input signal generated in step a. to generate transmitted radio signal;

c. receiving said transmitted radio signal generated in step b. with said antenna elements to generate antenna output signals;

d. separating first representation of said second radio signal from first representation of said first radio signal of said antenna output signals generate in step c. to generate separate first radio signals;

e. reducing said first multipath interference, second multipath interference, and other interference in said antenna output signals generated in step c. with said adaptive array to generate an adaptive array output signal including second representation of said first radio signal with reduced said first multipath interference, second representation of said second radio signal with reduced second multipath interference and reduced associated said other interference by adjusting said weights and to generate slave weight signals from said weights; and

f. reducing said second multipath interference and said other interference in said separate second radio signal generated in step d. with said slave weight network to generate an slave weight network output signal including second representation of said second radio signal with reduced said second multipath interference and reduced said other interference by applying said slave weight signals generated in step e. to associated said slave weights.

8. A method for using one adaptive array with weights, slave weight network with slave weights and plurality of antenna elements for reducing first multipath interference of first radio signal, second multipath interference of said second radio signal and other interference, where each input of said adaptive array and each corresponding input of said slave weight network are coupled to separate one of said antenna elements, and said adaptive array is configured for said first radio signal, said method comprising the steps of:

a. forming explicitly separable signal combination of said first radio signal and said second radio signal in same frequency channel to generate transmit antenna input signal;

b. transmitting said transmit antenna input signal generated in step a. to generate transmitted radio signal;

c. receiving said transmitted radio signal generated in step b. with said antenna elements to generate antenna output signals;

d. separating first representation of said first radio signal from first representation of said second radio signal for each one of said antenna output signals generate in step c. to generate separate first radio signals and separate second radio signals;

e. reducing said first multipath interference and said other interference in said separate first radio signals generated in step d. with said adaptive array to generate an adaptive array output signal including second representation of said first radio signal with reduced said first multipath interference and reduced associated other interference by adjusting said weights and to generate associated slave weight signals from said weights; and

f. reducing said second multipath interference and said other interference in said separate second radio signals generated in step d. with said slave weight network to generate an slave weight network output signal including second representation of said second radio signal with reduced said second multipath interference and reduced said associated other interference by applying said slave weight signals generated in step e. to said associated said slave weights.

9. A claim, as in claim 8, where said first radio signal is FM radio signal of IBOC system, said second radio signal is an OFDM signal of IBOC system, and said adaptive antenna is CMA adaptive antenna.

10. A method as in claim 8, wherein:

said adaptive array further includes;

a computing system; and

an algorithm representation of said adaptive array;

step c. further includes the step of;

g. generating a digital representation of each one of said antenna output signals; and

said method further includes the step of;

h. computing a real time digital representation of said adaptive array output signal from said digital representation of each of said antenna output signals of step f. with said computing system and said algorithm.

11. A method for using one adaptive filter with antenna for reducing first multipath interference of first radio signal, second multipath interference of second radio signal and other interference, where said second radio signal has power much less than said first radio signal, input of said adaptive filter is coupled to said antenna, and said adaptive filter is configured for said first radio signal, said method comprising the steps of:

a. forming separable signal combination of said first radio signal and said second radio signal in same frequency channel to generate transmit antenna input signal;

b. transmitting said transmit antenna input signal generated in step a. to generate transmitted radio signal;

c. receiving said transmitted radio signal generated in step b. with said antenna to generate antenna output signal;

d. reducing said first multipath interference, said second multipath interference and said other interference in representation of said antenna output signal generated in step c. with said adaptive filter to generate an adaptive filter output signal including representation of said first radio signal with reduced said first multipath interference, representation of said second radio signal with reduced said second multipath interference and reduced said other interference; and

e. separating said representation of second radio signal from said representation of first radio signal in said adaptive filter output signal generated in step d. to generate a separated representation of said second radio signal.

12. A method as in claim 11, wherein said first radio signal is FM radio signal of IBOC system, and said second radio signal is digital signal of said IBOC system.

13. A method as in claim 11, wherein said separable signal combination in step a. is explicitly separable.

14. A method for using one adaptive filter with weights, slave weight network with slave weights and antenna for reducing first multipath interference of first radio signal, second multipath interference of said second radio signal and other interference, where each input of said adaptive filter and input of said slave weight network are coupled to said antenna, and said adaptive filter is configured for said first radio signal, said method comprising the steps of:

a. forming explicitly separable signal combination of said first radio signal and said second radio signal in same frequency channel to generate transmit antenna input signal;

b. transmitting said transmit antenna input signal generated in step a. to generate transmitted radio signal;

c. receiving said transmitted radio signal generated in step b. with said antenna to generate antenna output signal;

d. separating first representation of said first radio signal from first representation of said second radio signal for said antenna output signal generate in step c. to generate separate first radio signal and separate second radio signal;

e. reducing said first multipath interference and said other interference in said separate first radio signal generated in step d. with said adaptive array to generate an adaptive array output signal including second representation of said first radio signal with reduced said first multipath interference and reduced associated other interference by adjusting said weights and to generate associated slave weight signals from said weights; and

f. reducing said second multipath interference and said other interference in said separate second radio signal generated in step d. with said slave weight network to generate an slave weight network output signal including second representation of said second radio signal with reduced said second multipath interference and reduced said associated other interference by applying said slave weight signals generated in step e. to associated said slave weights.

15. Apparatus for using one adaptive array for reducing first multipath interference of first radio signal, second multipath interference of second radio signal and other interference, where said adaptive array is configured for said first radio signal, said first radio signal and said second radio signal are separable, said second radio signal is transmitted from the same transmitter antenna and in same frequency channel with said first radio signal with a power much less than said first radio signal, said adaptive array including N inputs, N is at least 2, said apparatus comprising:

N antenna elements with output terminal to generate separate N received signals;

N bandpass filters with input terminal and output terminal, each said input terminal coupled to receive associated one of said N received signals from associated one of said N antenna elements to generate bandpass signal;

an adaptive array with output terminal and N input terminals with each one of said N input terminals coupled to said output terminal of associated one of said N bandpass filters to receive associated said bandpass signal for generating adaptive array output signal with representation of first radio signal and representation of said second radio signal with reduced said first multipath interference, reduced said second multipath interference and reduced said other interference with said adaptive array output signal applied to said output terminal; and

a separator with an input terminal, said input terminal coupled to said output terminal of said adaptive array to receive said adaptive array output signal to separate said representation of second radio signal from said representation of said first radio signal to generate separate second radio.

16. Apparatus for using one adaptive array for reducing first multipath interference of first radio signal, second multipath interference of second radio signal and other interference, where said first radio signal and said second radio signals are explicitly separable, said second radio signal is transmitted from the same transmitter antenna and in same frequency channel with said first radio signal with a power much less than said first radio signal, said adaptive array including N inputs, where N is at least 2, and said adaptive array is configured for said first radio signal, said apparatus comprising:

N antenna elements with output terminal to generate separate N received signals;

N bandpass filters with input terminal and output terminal, each said input terminal coupled to receive associated one of said N received signals from associated one of said N antenna elements to generate bandpass signal;

adaptive array with output terminal and N input terminals with each one of said N input terminals coupled to said output terminal of associated one of said N bandpass filters to receive associated bandpass signal for generating adaptive array output signal with representation of said first radio signal and representation of said second radio signal with reduced said first multipath interference, reduced said second multipath interference and reduced said other interference with said adaptive array output signal applied to said output terminal;

a separator with an input terminal and output terminal, said input terminal coupled to said output terminal of said adaptive array to receive said adaptive array output signal to separate said representation of second radio signal from said representation of said first radio signal to generate separate second radio signal with said separate second radio signal applied to said output terminal; and

a receiver with input terminal, said input terminal coupled to said output terminal of said separator to receive said separate second radio signal.

17. Apparatus as in claim 16, wherein said first radio signal is FM radio signal of IBOC system and said second radio signal is digital signal of IBOC system.

18. A system as in claim 16, wherein:

said adaptive array includes;

N second analog-to-digital converters having an input terminal and an output digital data port with said input terminal of each of said N second analog-to-digital converters disposed to be coupled to associated one of each of said N input terminals of said adaptive array to receive associated bandpass signal to generate a digital representation of said bandpass signal; and

a computing system having N input signal digital data ports and one output terminal with each of said N input signal digital data ports coupled to said output signal digital data port of associated one of said second N analog-to-digital converters, said computing system computing a real time digital representation of said adaptive array output signal with an algorithm representation of said adaptive array with said digital representation of said adaptive array output signal applied to said output terminal of said computing system.

19. Apparatus for using one adaptive array and slave weight network for reducing first multipath interference of first radio signal, second multipath interference of second radio signal and other interference, where said first radio signal and said second radio signals are explicitly separable, said second radio signal is transmitted from the same transmitter antenna and in same frequency channel with said first radio signal, said adaptive array and slave weight network including N inputs, where N is at least 2, M weights and associated M slave weights per each one of said N inputs, where M is at least 2, NM weights, NM slave weights, and said adaptive array is configured for said first radio signal, said apparatus comprising:

N antenna elements with output terminal to generate separate N received signals;

N bandpass filters with input terminal and output terminal, each said input terminal coupled to receive associated one of said N received signals from associated one of said N antenna elements to generate bandpass signal;

N separators with an input terminal and first and second output terminals, said input terminal coupled to said output terminal of associated one of said N bandpass filters to receive said bandpass signal to separate said representation of first radio signal from said representation of second radio signal to generate separate first radio signal with said separate first radio signal applied to said first output terminal and generate separate second radio signal with said separate second radio signal applied to said second output terminal;

an adaptive array with NM weights, N input terminals, NM slave weight output terminals, with each one of said N input terminals coupled to said first output terminal of associated one of said N separators to receive associated separate first radio signal for generating adaptive array output signal with representation of said first radio with reduced said first multipath interference and reduced associated said other interference generating NM slave weight output signals, each one of said NM slave weight output signals associated separate one of said NM weights, with each one of said NM slave weight output signals applied to associated one of said NM slave weight output terminals;

a slave weight network with NM slave weights, N slave weight network input terminals, NM slave weight input terminals, and output terminal with each one of said N slave weight network input terminals coupled to said second output terminal of associated one of said N separators to receive associated separate second radio signal, said NM slave weight input terminals coupled to associated one of said NM slave weight output terminals to receive associated one of said NM slave weight output signals for generating slave weight network output signal with representation of said second radio with reduced said second multipath interference and reduced said associated other interference, and applying said slave weight network output signal to said output terminal; and

a receiver with input terminal, said input terminal coupled to said output terminal of said slave weight network to receive said slave weight network signal.

20. Apparatus as in claim 19, wherein said adaptive array further includes:

an output terminal to which said adaptive array output signal is applied; and

a second receiver with input terminal coupled to said adaptive array output terminal to receive said adaptive array output signal.

21. Apparatus as in claim 19, wherein said first radio signal is FM radio signal of IBOC system, said second radio signal is OFDM signal of IBOC system, and said adaptive array is CMA adaptive array.