Full Duplex Wireless Transmission with Channel Phase-Based Encryption

• US 20130301688A1
• Filed: 05/13/2013
• Published: 11/14/2013
• Est. Priority Date: 05/13/2012
• Status: Active Grant

• Current Assignee: Amir Keyvan Khandani
• Original Assignee: Amir Keyvan Khandani
• Inventors: Khandani, Amir Keyvan
• Granted Patent: US 9,572,038 B2
• Time in Patent Office: Days
• US Class Current: 375/211
• CPC Class Codes: H04B 1/123 using adaptive balancing or compensation means adaptive filter circuits and algorithms H03H
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 7/026 Co-operative diversity, e.g. using fixed or mobile stations as relays
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0478 Special codebook structures directed to feedback optimisation
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04B 7/0669 using different channel coding between antennas space-time coding H04L1/0618
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04L 1/18 Automatic repetition systems, e.g. Van Duuren systems
• CPC Class Codes: H04L 1/1825 Adaptation of specific ARQ protocol parameters according to transmission conditions
• CPC Class Codes: H04L 1/1896 ARQ related signaling
• CPC Class Codes: H04L 2001/0097 Relays
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04W 12/04 Key management, e.g. using generic bootstrapping architecture [GBA]
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks

Abstract

A method comprising: at a first transceiver, transmitting a plurality of signals to a second transceiver and receiving corresponding receive signals from the second transceiver, wherein each transmitted signal is sent using a channel perturbation; measuring a plurality of phase values, wherein each phase value is a phase difference between one of the plurality of transmitted signals and corresponding receive signal; masking a subsequent phase modulated signal employing phase rotation at the first transceiver using the plurality of phase values.

Claims

1. A method comprising:

at a first transceiver, transmitting a plurality of signals to a second transceiver and receiving corresponding receive signals from the second transceiver, wherein each transmitted signal is sent using a channel perturbation;

measuring a plurality of phase values, wherein each phase value is a phase difference between one of the plurality of transmitted signals and corresponding receive signal;

masking a subsequent phase modulated signal employing phase rotation at the first transceiver using the plurality of phase values.

2. The method of claim 1 wherein the first and second transceiver are full-duplex nodes.

3. The method of claim 1 wherein the first transceiver acts as a full-duplex repeater for a plurality of signals initiated by and transmitted from the second transceiver.

4. The method of claim 1 wherein the subsequent phase modulated signal is an encryption key.

5. The method of claim 4, wherein the encryption key is encoded with an error-correction code, and wherein the plurality of phase values includes phase noise that is corrected using the error-correction code.

6. The method of claim 1 wherein the channel is perturbed using radio frequency mirrors to alter antenna environments.

7. The method of claim 1 wherein the first transceiver is full duplex, and wherein

9. The method of claim 7 wherein the first transceiver performs calibration to measure its internal phase.

10. The method of claim 7 wherein the first transceiver measures the filters to be used in the cascaded analog cancellation using a low power pilot.

11. The method of claim 7 wherein the first transceiver acts as the master and transmits a sinusoidal signal of a known frequency and the second transceiver relays this signal sample by sample back to the first transceiver.

12. The method of claim 1 wherein the first transceiver accounts for an internal phase shift by subtracting a value of the internal phase shift from each of the plurality of phase values as the mask.

8. symmetrical antenna structures are used to reduce coupling and self-interference, and wherein a cascade of multiple analog cancellation is used to further reduce coupling and self-interference.

13. A method comprising:

measuring loop-back channels from a transmitter of a first transceiver to a receiver of the first transceiver;

transmitting at least one symbol and measuring a first relative phase of at least one returned symbol;

receiving at least one symbol and retransmitting the at least one received symbol;

perturb the channel at the first transceiver to change the channel phase;

transmitting at least one additional symbol and measuring a second relative phase of at least one additional returned symbol.

14. The method of claim 13 wherein a subsequent phase modulated signal is transmitted using a mask derived from the first and second relative phase.

15. The method of claim 13, wherein the subsequent phase modulated signal is an encryption key encoded with an error-correction code.