FULL DUPLEX RADIO

• US 20160119019A1
• Filed: 08/14/2015
• Published: 04/28/2016
• Est. Priority Date: 10/22/2014
• Status: Active Grant

• Current Assignee: Analog Devices International Unlimited Company (Analog Devices, Inc.)
• Original Assignee: Analog Devices Global Unlimited Company (Analog Devices, Inc.)
• Inventors: Pratt, Patrick
• Granted Patent: US 10,097,233 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04L 25/00 Baseband systems
• CPC Class Codes: H04L 5/1461 Suppression of signals in the return path, i.e. bidirectional control circuits
• CPC Class Codes: H04W 4/70 Services for machine-to-machine communication [M2M] or machine type communication [MTC]

Abstract

Embodiments of full duplex radios are disclosed herein. For example, a radio may include: a first transmitter, a second transmitter, and a receiver. The first transmitter may be configured to receive an input signal, process the input signal to generate a first transmit signal, and transmit the first transmit signal. The second transmitter may be configured to receive the input signal, process the input signal to generate a second transmit signal, and couple the second transmit signal into an input path of the receiver. Leakage at the receiver may thus be reduced. Some embodiments of a radio may also include a base band correction circuit and means for reducing transmitter noise that leaks into the receiver.

Claims

1. A radio, comprising:

a first transmitter;

a second transmitter; and

a receiver;

wherein;

the first transmitter is to receive an input signal, to process the input signal to generate a first transmit signal, and to transmit the first transmit signal, and

the second transmitter is to receive the input signal, to process the input signal to generate a second transmit signal, and to couple the second transmit signal into an input path of the receiver.

2. The radio of claim 1, wherein the second transmitter further comprises a filter to receive the input signal and to filter the input signal, and an adaptation engine to receive an output from the receiver, and to examine the output from the receiver so as to identify components of the first transmit signal, and to modify filter coefficients of the filter so as to reduce the power of the first transmit signal within the receiver.

3. The radio of claim 1, further comprising a baseband cancellation engine to receive the input signal and to generate a correction to be introduced into the baseband processing components of the receiver.

4. The radio of claim 3, wherein the baseband cancellation engine is to, as part of generation of a correction, generate an analog correction signal for introduction into a receiver signal path upstream of an analog to digital converter of the receiver.

5. The radio of claim 3, wherein the baseband cancellation engine is to, as part of generation of a correction, generate a digital correction signal for combination with a data stream output from an analog to digital converter of the receiver.

6. The radio of claim 3, where the baseband cancellation engine is to, as part of generation of a correction, monitor one or more signals within the receiver and adapt a correction signal generated by the cancellation engine to reduce the power of the first transmit signal at the output of the receiver.

7. The radio of claim 1, further comprising a second receiver and a transmit noise canceller, and wherein signal combiners are provided to couple a scaled combination of the first and second transmit signals to an input of the second receiver, and the transmit noise canceller is to receive an output from the second receiver and to calculate a noise reduction signal that is to be combined with the output of the first receiver.

8. The radio of claim 1, wherein the radio is a full duplex radio in which the transmitter transmits at a first frequency, the receiver receives at the first frequency, and the transmitter and receiver can operate concurrently.

9. The radio of claim 1, further comprising a white space detector to detect an unused frequency band within a predetermined part of a frequency spectrum, and to adapt the transmitter and receiver to operate at the unused frequency band.

10. The radio of claim 1, wherein the radio is a MIMO radio having a plurality of transmitters and a plurality of receivers, and wherein the plurality of transmitters are to generate a plurality of transmit signals to be coupled into a corresponding plurality of receive paths of the plurality of transceivers receivers to reduce interference from one MIMO transmit-receive pairing of a transmitter and receiver to another transmit-receive pairing of a transmitter and receiver.

11. The radio of claim 1, wherein the radio is part of a mobile telephony unit.

12. The radio of claim 1, wherein the radio is part of a machine-to-machine communication system.

13. A radio, comprising:

a first transmit unit and a first receive unit, where the first transmit unit comprises;

a first transmitter to receive an input signal, and to up-convert it for supply to an antenna, and

a second transmitter to receive the input signal, to adapt it and to up convert it to generate an RF correction signal to be introduced into an RF receive path of the first receive unit so as to reduce a power level of the signal of the first transmitter at an RF amplifier of the first receive unit;

wherein the radio further comprises means for estimating a noise contribution from the first and second transmitters and for subtracting the noise contribution from an output of a receiver of the first transmit unit.

14. The radio of claim 13, wherein the means for estimating the noise contribution comprises a combining circuit for taking the output of the first transmitter and the output of the second transmitter and combining them such that information bearing components of the outputs substantially cancel, thereby leaving a combined noise component, and wherein the combined noise component is to be demodulated by a second receiver.

15. The radio of claim 14, further comprising a second transmit unit and a second receive unit, wherein the first transmit unit is to provide a first transmit unit cancellation signal to an RF path of the second receive unit prior to an RF front end amplifier of the second receive unit.

16. The radio of claim 15, wherein the first transmit unit further comprises a third transmitter to receive the input signal and to generate the first transmit unit correction signal.

17. The radio of claim 16, wherein the third transmitter includes an adaptation engine that is to receive an output of the second receive unit, analyze the output originating from the first transmitter, and modify a signal processing function applied to the input signal so as to reduce the influence of the first transmitter on the second receiver.

18. A duplex radio, comprising:

a transmitter;

a receiver;

an RF correction circuit to reduce a received signal from the transmitter at an RF front end of the receiver; and

a baseband correction circuit to reduce a received signal from the transmitter in a baseband portion of the receiver.

19. The duplex radio of claim 18, wherein the baseband correction circuit comprises a correction engine that is to receive a signal input stream to be provided to the transmitter, receive an output stream from the receiver, compare the output stream with a signal input stream to identify signal components of the signal input stream, and estimate parameters of a signal processing operation to be applied to the input stream to generate a correction signal to be combined with the output stream or injected into a baseband path of the receiver.

20. The duplex radio of claim 18, wherein the radio is to provide back haul from a mobile telephony base station.