Duplexing apparatus, wireless devices and related methods

Patent metadata

Field	Value
Publication number	US-9929854-B2
Application number	US-201514614371-A
Country	US
Kind code	B2
Filing date	Feb 4, 2015
Priority date	Feb 4, 2014
Publication date	Mar 27, 2018
Grant date	Mar 27, 2018

Abstract

The invention provides duplexing apparatus, wireless devices and methods for duplexing signals in which measurements are taken at multiple frequencies across a frequency band of interest, and in which a balancing impedance is controlled as a function of those measurements. Isolation between the RX and TX nodes is enhanced across the frequency band as a result.

First claim

What is claimed is:

1. An apparatus for duplexing signals to be transmitted wirelessly and signals received wirelessly by an antenna, comprising:
a hybrid junction comprising an antenna node for coupling to the antenna, an input node for receiving a signal to be transmitted by the antenna, an output node for outputting a signal received wirelessly by the antenna, and a balancing node;
a variable impedance coupled to the balancing node; and
a controller arranged to:
a) set the variable impedance to a first impedance setting;
b) transmit a first transmit signal at a first transmit frequency in a first frequency band;
c) measure a first signal at the output node at a first receive frequency in a second frequency band \as a result of the first signal transmitted at the first transmit frequency;
d) select a second impedance setting of the variable impedance;
e) transmit a second transmit signal at a second transmit frequency in the first frequency band;
f) measure a second signal at the output node at a second receive frequency in the second frequency band as a result of the second signal transmitted at the second transmit frequency;
g) employ a system of equations comprising variables associating the first measured signal, the second measured signal, the first impedance setting, and the second impedance setting; and
h) determine a third impedance setting to isolate the input node from the output node of the hybrid junction using the system of equations.

2. The apparatus according to claim 1 , wherein the first frequency band and the second frequency band do not overlap, overlap partially or overlap completely.

3. The apparatus according to claim 1 , wherein the first transmit frequency and the first receive frequency are identical or different.

4. The apparatus according to claim 1 , wherein the controller is further arranged to:
for each measurement in operation c), calculate respective quantities representing interference and balance channels of the hybrid junction; and
control the variable impedance as a function of the respective quantities.

5. The apparatus according to claim 1 , wherein the controller is configured to control the variable impedance such that a reflection coefficient at the balancing node is proportional to a mean reflection coefficient of the antenna over the first or second frequency band.

6. The apparatus according to claim 1 , wherein the controller is arranged to control the variable impedance further as a function of at least one of a power density with which signals are transmitted by the antenna as a function of frequency, and a filter gain with which signals are received as a function of frequency.

7. The apparatus according to claim 1 , wherein the controller is configured to: set the variable impedance to a further impedance setting; repeat operations b) and c) for the further impedance setting in order to obtain another plurality of measurements at the output node; and control the variable impedance further as a function of the another plurality of measurements.

8. The apparatus according to claim 1 , wherein the controller is configured to carry out operations a) to h) periodically.

9. The apparatus according to claim 1 , wherein the controller is arranged to control the variable impedance to take an impedance proportional to

1
+

k
⁢

Γ
ANT

⁡

(
ω
)

_

1
-

k
⁢

Γ
ANT

⁡

(
ω
)

_

,

where Γ ANT (ω) is the mean reflection coefficient of the antenna over the first or second frequency band, and where k is a constant of proportionality.

10. A wireless device comprising an antenna and an apparatus for duplexing signals to be transmitted wirelessly and signals received wirelessly by an antenna, comprising:
a hybrid junction comprising an antenna node for coupling to the antenna, an input node for receiving a signal to be transmitted by the antenna, an output node for outputting a signal received wirelessly by the antenna, and a balancing node;
a variable impedance coupled to the balancing node; and
a controller arranged to:
a) set the variable impedance to a first impedance setting;
b) transmit a first transmit signal at a first transmit frequency in a first frequency band;
c) measure a first signal at the output node at a first receive frequency in a second frequency band as a result of the first signal transmitted at the first transmit frequency;

d) select a second impedance setting of the variable impedance;
e) transmit a second transmit signal at a second transmit frequency in the first frequency band;

f) measure a second signal at the output node at a second receive frequency in the second frequency band as a result of the second signal transmitted at the second transmit frequency;
g) employ a system of equations comprising variables associating the first measured signal, the second measured signal, the first impedance setting, and the second impedance setting; and
h) determine a third impedance setting to isolate the input node from the output node of the hybrid junction using the system of equations.

11. A method of duplexing signals to be transmitted wirelessly and signals received wirelessly by an antenna, in a system comprising a hybrid junction, the hybrid junction comprising an antenna node for coupling to the antenna, an input node for receiving a signal to be transmitted by the antenna, an output node for outputting a signal received wirelessly by the antenna, a balancing node, and a variable impedance coupled to the balancing node, the method comprising:
a) setting the variable impedance to a first impedance setting;
b) transmitting a first transmit signal at a first transmit frequency in a first frequency band;
c) measuring a first signal at the output node at a first receive frequency in a second frequency band as a result of the signal transmitted at the first frequency;
d) selecting a second impedance setting of the variable impedance;
e) transmitting a second transmit signal at a second transmit frequency in the first frequency band;
f) measuring a second signal at the output node at a second receive frequency in the second frequency band as a result of the second signal transmitted at the second transmit frequency;
g) employing a system of equations comprising variables associating the first measured signal, the second measured signal, the first impedance setting, and the second impedance setting; and
h) determining a third impedance setting to isolate the input node from the output node of the hybrid junction us

Assignees

• Ublox Ag
• Ublox Ag

Inventors

• Laughlin Leo
• Marshall Christopher

Classifications

• H04B1/525 Primary

  with means for reducing leakage of transmitter signal into the receiver · CPC title

• H04L5/1461 Primary

  Suppression of signals in the return path, i.e. bidirectional control circuits · CPC title

• H04B1/581

  using a transformer · CPC title

• H04L5/1438 Primary

  Negotiation of transmission parameters prior to communication (modified according to link quality H04L1/0001) · CPC title

• H04W24/08

  Testing, {supervising or monitoring} using real traffic · CPC title