Technique for full duplex with single antenna

• US 10,644,394 B2
• Filed: 02/16/2017
• Issued: 05/05/2020
• Est. Priority Date: 06/13/2016
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Watkins, Gavin
• Primary Examiner(s): Smith, Graham P
• Assistant Examiner(s): Kim, Jae K
• Application Number:
  US15/434,505
• Publication Number:
  US 20170358857A1
• Time in Patent Office: 1,174 Days
• CPC Class Codes: H01Q 1/525 between emitting and receiving antennas
• CPC Class Codes: H01Q 21/00 Antenna arrays or systems arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system H01Q3/00
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence
• CPC Class Codes: H04B 1/56 with provision for simultaneous communication in two directions
• CPC Class Codes: H04B 1/58 Hybrid arrangements, i.e. arrangements for transition from single-path two-direction transmission to single-direction transmission on each of two paths or vice versa
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex

Abstract

A system and method for duplexing radio frequency signals for full-duplex transmission and reception by an antenna. The system comprises a signal coupler comprising an antenna node configured to be connected to the antenna, an input node for receiving radio frequency signals for transmission by the antenna, an output node for outputting radio frequency signals received by the antenna, and a coupling node. The system further comprises a variable impedance element connected to the coupling node to reduce interference between the signals for transmission by the antenna and the signals received by the antenna, the variable impedance element comprising a variable phase shifter connected to a variable attenuator.

Claims

1. A system comprising:

baseband circuitry configured to modulate a transmission signal having a first frequency band, and to demodulate a reception signal having a second frequency band, wherein the transmission signal is to be transmitted via an antenna, and the reception signal is received via the antenna, the first frequency band and the second frequency band are at least partially overlapped, and the transmission signal and the reception signal are subject to a full duplex scheme;

a signal coupler comprising;

an antenna node configured to be electrically coupled to the antenna;

an input node configured to receive, from the baseband circuitry, the transmission signal to be transmitted via both the antenna node and the antenna;

an output node configured to transmit, to the baseband circuitry, the reception signal received via both the antenna node and the antenna; and

a coupling node electrically coupled to the antenna node; and

a variable impedance element electrically coupled to the coupling node to reduce interference between the transmission signal and the reception signal, the variable impedance element comprising a power splitter and a plurality of sets of a variable phase shifter and a variable attenuator, each variable phase shifter being electrically coupled to a corresponding variable attenuator,

wherein a signal output from the coupling node is split by the power splitter, and signals split by the power splitter are re-combined by the power splitter, and the signal re-combined by the power splitter are input to the coupling node.

2. A system according to claim 1 wherein the system is configured to adjust an impedance of the variable impedance element to reduce the interference between the transmission signal and the reception signal.

3. A system according to claim 1 wherein the system comprises one or more further variable impedance elements and wherein the variable impedance element and the one or more further variable impedance elements are coupled to a coupling terminal via the power splitter.

4. A multiple-input and multiple-output system for duplexing radio frequency signals, the system comprising a plurality of systems according to claim 1 wherein the systems are connected to each other via a common node connected to the coupling node of each system.

5. The multiple-input and multiple-output system of claim 4 wherein one or more of the systems have a variable impedance element located between the coupling node for the respective system and the common node.

6. The multiple-input and multiple-output system of claim 4 wherein each of the systems has a variable impedance element located between the coupling node for the respective system and the common node.

7. A device for wireless communication comprising:

a system according to claim 1;

the antenna connected to the antenna node of the signal coupler for full duplex wireless communication; and

a controller configured to;

provide the transmission signal to the input node of the signal coupler;

receive from the output node of the signal coupler the reception signal; and

control the variable impedance element to reduce the interference between the transmission signal and the reception signal.

11. A multiple-input and multiple-output method for duplexing signals, the method comprising connecting a plurality of systems according to claim 1 to each other via a common node connected to the coupling node of each system.

12. The multiple-input and multiple-output method of claim 11 wherein one or more of the systems are connected to the coupling node via a variable impedance element located between the coupling node for the respective system and the common node.

13. The multiple-input and multiple-output method of claim 11 wherein each of the systems is connected to the coupling node via a respective variable impedance element located between the coupling node for the respective system and the common node.

14. A system according to claim 1, further comprising a controller configured to control both of a variable phase shifter and a variable attenuator independently.

15. A system according to claim 1, further comprising a controller configured to control a set of the variable phase shifter and the variable attenuator to adjust a phase and a magnitude of a reflection coefficient at the coupling node, the reflection coefficient corresponding to a reflection signal returned to the antenna.

8. A method being performed by a system comprising

baseband circuitry configured to modulate a transmission signal having a first frequency band, and to demodulate a reception signal having a second frequency band, wherein the transmission signal is to be transmitted via an antenna, and the reception signal is received via the antenna, the first frequency band and the second frequency band are at least partially overlapped, and the transmission signal and the reception signal are subject to a full duplex scheme,

a signal coupler comprising an antenna node configured to be electrically coupled to the antenna, an input node, an output node and a coupling node, and

a variable impedance element electrically coupled to the coupling node, the variable impedance element comprising a power splitter and a plurality of sets of a variable phase shifter and a variable attenuator, each variable phase shifter being electrically coupled to a corresponding variable attenuator,

the method comprising:

receiving at the input node, from the baseband circuitry, the transmission signal to be transmitted via both the antenna node and the antenna and transmitting, to the baseband circuitry, the transmission signal at the antenna node;

receiving at the antenna node the reception signal received by the antenna and transmitting the reception signal at the output node;

applying a variable impedance to the coupling node via the variable impedance element to reduce interference between the transmission signal and the reception signal;

splitting a signal output from the coupling node by the power splitter, and re-combining signals split by the power splitter, and inputting the signal re-combined by the power splitter to the coupling node.

9. A method according to claim 8 wherein the method further comprises adjusting an impedance of the variable impedance element to reduce the interference between the transmission signal and the reception signal.

10. A method according to claim 8 wherein the system comprises one or more further variable impedance elements, the variable impedance element and the one or more further variable impedance elements are coupled to a coupling terminal via the power splitter, and the method further comprises applying one or more further variable impedances to the coupling node via the one or more further variable impedance elements.