SECURE RADIO METHODS AND APPARATUS

• US 20170019235A1
• Filed: 12/29/2015
• Published: 01/19/2017
• Est. Priority Date: 07/16/2015
• Status: Active Grant

• Current Assignee: LGS Innovations LLC (CACI International Incorporated)
• Original Assignee: LGS Innovations LLC (CACI International Incorporated)
• Inventors: BRANNON, ALAN SCOTT, PACK, RILEY NELSON, BAKER, BENJAMIN JOSEPH
• Granted Patent: US 10,594,469 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H04B 1/0003 Software-defined radio [SDR] systems, i.e. systems wherein components typically implemented in hardware, e.g. filters or modulators/demodulators, are implented using software, e.g. by involving an AD or DA conversion stage such that at least part of the signal processing is performed in the digital domain digital baseband systems H04L25/00; digital modulation/demodulation H04L27/00; CDMA H04B1/707; TDMA H04B7/2643; image transmission H04N5/00
• CPC Class Codes: H04B 1/0042 Digital filtering H04B1/0035 takes precedence; digital filters per se H03H17/00
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence
• CPC Class Codes: H04B 1/10 Means associated with receiver for limiting or suppressing noise or interference
• 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 1/401 for selecting or indicating operating mode
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 1/713 using frequency hopping
• CPC Class Codes: H04B 1/715 Interference-related aspects
• CPC Class Codes: H04B 15/00 Suppression or limitation of noise or interference by means associated with receiver H04B1/10
• CPC Class Codes: H04B 15/02 Reducing interference from electric apparatus by means located at or near the interfering apparatus
• CPC Class Codes: H04B 2001/0408 with power amplifiers
• CPC Class Codes: H04L 25/0212 of impulse response
• CPC Class Codes: H04L 25/025 using least-mean-square [LMS] method
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04L 5/1461 Suppression of signals in the return path, i.e. bidirectional control circuits

Abstract

The present application describes a computer-implemented method for frequency hopping including configuring a radio front end to operate on a first frequency; receiving a transmit signal in a first path in the radio front end; amplifying a transmit signal in the first path; phase shifting the transmit signal in a second path in the radio front end, the second path being different from the first path; coupling the amplified transmit signal to a third path in the radio front end; coupling the phase-shifted transmit signal in the second path to the amplified transmit signal in the third path to form a carrier-cancelled signal in a fourth path in the radio front end in the radio front end; phase shifting the carrier-cancelled signal in the fourth path; coupling the phase-shifted carrier-cancelled signal in the fourth path to the amplified transmit

Claims

1. A computer-implemented method for frequency hopping comprising:

configuring a radio front end to operate on a first frequency;

receiving a transmit signal in a first path in the radio front end;

amplifying a transmit signal in the first path;

phase shifting the transmit signal in a second path in the radio front end, the second path being different from the first path;

coupling the amplified transmit signal to a third path in the radio front end;

coupling the phase-shifted transmit signal in the second path to the amplified transmit signal in the third path to form a carrier-cancelled signal in a fourth path in the radio front end in the radio front end;

phase shifting the carrier-cancelled signal in the fourth path;

coupling the phase-shifted carrier-cancelled signal in the fourth path to the amplified transmit signal in the first path; and

reconfiguring the radio front end to operate on a second frequency.

2. The method of claim 1, further comprising:

controlling a delay of the phase shifting of the transmit signal in the second path.

3. The method of claim 1, further comprising:

controlling an amplitude of the phase shifted transmit signal in the second path.

4. The method of claim 1, further comprising:

controlling a delay of the phase shifting of the carrier-cancelled signal in the fourth path.

5. The method of claim 1, further comprising:

controlling an amplitude of the carrier-cancelled signal in the fourth path.

6. The method of claim 1, wherein the first frequency is in a different frequency band than the second frequency.

7. The method of claim 1, wherein the first and second frequencies are determined by a radio access technology.

8. The method of claim 1, further comprising:

filtering the phase-shifted transmit signal in the second path to remove energy in a receive frequency band, the receive frequency band being different from a transmit frequency band.

9. The method of claim 8, further comprising:

filtering the transmit signal in the first path; and

adjusting a transmit band group delay of the filtered transmit signal in the first path to equal a transmit band group delay of the filtered transmit signal in the second path.

10. A computer-implemented method for frequency hopping comprising:

upconverting a first tone to a first frequency and a second tone to a second frequency;

injecting the upconverted first tone into a receive channel;

sweeping the upconverted second tone through a frequency band of the receive channel;

characterizing the receive channel using the upconverted second tone;

processing the transmit signal using an infinite impulse response filter based on the characterized receive channel to generate an interference-cancelling signal; and

upconverting the first tone to a third frequency and the second tone to a fourth frequency.

11. The method of claim 10, wherein:

the first, second, third, and fourth frequencies are precalibrated so that each of the frequencies operate on a different frequency band.

12. The method of claim 10, further comprising:

upconverting a third tone to a fifth frequency.

13. The method of claim 10, further comprising:

coupling the interference-cancelling signal to a received signal containing interference.

14. The method of claim 10, wherein the first frequency and the second frequency are pre-calibrated to operate in a plurality of frequency bands.

15. The method of claim 10, wherein the upconverted first tone overlays the frequency band of the receive channel.

16. The method of claim 10, wherein the first and second frequencies are in a different frequency band than the third and fourth frequencies.

17. The method of claim 10, further comprising:

generating coefficients of the infinite impulse response filter using the receive channel characteristics to model the receive channel.

18. The method of claim 17, wherein the coefficients of the infinite impulse response filter are generated in conjunction with a least-squares estimator circuit.

19. The method of claim 10, wherein the first frequency and the second frequency are determined by a radio access technology.

20. A computer-implemented process for frequency hopping in a network comprising:

providing a radio front end including a software-implemented filter for processing a signal from a transmitter, the radio front end being calibrated to operate on multiple frequencies associated with the transmitter;

configuring the radio front end to operate on a first frequency for receiving the signal;

assigning a second frequency in the radio front end for receiving the signal; and

reconfiguring the radio front end to operate on the second frequency.

21. The process according to claim 20, wherein the assigning step is controlled by a frequency hopping algorithm.

22. The process according to claim 21, further comprising:

identifying a triggering event before the assigning step.

23. The process according to claim 20, wherein

the radio front end operates in a frequency division duplex system, and

the network is selected from cellular, Wi-Fi and combinations thereof.

24. The process according to claim 20, wherein the assigning and reconfiguring steps occur during a single call.

25. The process according to claim 24, wherein the frequency hopping during the call enhances communications security.