U.S. patent application number 16/120628 was filed with the patent office on 2019-01-17 for antenna alignment using unmanned aerial vehicle.
The applicant listed for this patent is TELEFONAKTIEBOLAGET LM ERICSSON (PUBL). Invention is credited to Anders AHLSTROM, Bengt-Erik OLSSON, Jan SANDBERG, Stefan THORESSON, Ulf WENNERLOF.
Application Number | 20190020422 16/120628 |
Document ID | / |
Family ID | 54324985 |
Filed Date | 2019-01-17 |
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United States Patent
Application |
20190020422 |
Kind Code |
A1 |
WENNERLOF; Ulf ; et
al. |
January 17, 2019 |
ANTENNA ALIGNMENT USING UNMANNED AERIAL VEHICLE
Abstract
A system for antenna alignment of a directional antenna used for
wireless communication with respect to a target location. The
system comprising the directional antenna and an unmanned aerial
vehicle, UAV, arranged to be deployed in relation to the target
location. The system is configured for transmission of an alignment
signal between the UAV and the directional antenna and also for
measuring a level of antenna alignment of the directional antenna
with respect to the target location, based on the alignment signal
transmission.
Inventors: |
WENNERLOF; Ulf; (Ojersjo,
SE) ; AHLSTROM; Anders; (Vallda, SE) ;
THORESSON; Stefan; (Lindome, SE) ; SANDBERG; Jan;
(Frillesas, SE) ; OLSSON; Bengt-Erik; (Mountain
Lakes, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TELEFONAKTIEBOLAGET LM ERICSSON (PUBL) |
Stockholm |
|
SE |
|
|
Family ID: |
54324985 |
Appl. No.: |
16/120628 |
Filed: |
September 4, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14785901 |
Oct 21, 2015 |
10103824 |
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PCT/EP2015/073822 |
Oct 14, 2015 |
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16120628 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04B 17/12 20150115;
H01Q 1/1257 20130101; H04W 16/18 20130101; G01R 29/10 20130101;
H04B 7/0619 20130101; H01Q 3/08 20130101; H04B 7/18504
20130101 |
International
Class: |
H04B 17/12 20060101
H04B017/12; H04B 7/06 20060101 H04B007/06; H01Q 3/08 20060101
H01Q003/08; H04B 7/185 20060101 H04B007/185; G01R 29/10 20060101
G01R029/10; H01Q 1/12 20060101 H01Q001/12; H04W 16/18 20060101
H04W016/18 |
Claims
1. A system for antenna alignment of a directional antenna used for
wireless communication with respect to a target location, the
system comprising; the directional antenna, and an unmanned aerial
vehicle, UAV, arranged to be deployed in relation to the target
location, the system is configured for transmission of an alignment
signal between the UAV and the directional antenna, the system is
also configured for measuring a level of antenna alignment of the
directional antenna with respect to the target location, based on
the alignment signal transmission.
2. The system according to claim 1, wherein the directional antenna
comprises an adjustment module, the adjustment module being
arranged for aligning the directional antenna with respect to the
target location based on the measured level of antenna
alignment.
3. An unmanned aerial vehicle, UAV, for aligning a directional
antenna used for wireless communication with respect to a target
location, the UAV being arranged for deployment in relation to the
target location, and comprising an antenna alignment module
configured for transmission of an alignment signal between the UAV
and the directional antenna, wherein the transmission comprises any
of transmitting and receiving the alignment signal, the alignment
signal is arranged to indicate a level of antenna alignment of the
directional antenna with respect to the target location.
4. The UAV according to claim 3 further being arranged to be
deployed along a flight path in a vicinity of the target
location.
5. The UAV according to claim 3, further comprising a positioning
module arranged to determine a current position of the UAV.
6. The UAV according to claim 3, further comprising a control
module arranged to control a position of the UAV.
7. The UAV according to claim 6, wherein the control module is
arranged to control the position of the UAV based on a current
position of the UAV determined by the positioning module and on the
target location.
8. The UAV according to claim 6, wherein the control module is
arranged to control the position of the UAV based on an external
control signal received from a remote location via a communications
module comprised in the control module.
9. The UAV according to claim 3, wherein the alignment module
comprises a receiver module arranged to receive the alignment
signal from the directional antenna.
10. The UAV, according to claim 9, wherein the alignment module is
arranged to measure a signal quality of the received alignment
signal.
11. The UAV according to claim 10, wherein the alignment module is
arranged to generate and transmit an antenna alignment level
measurement report, based on the measuring of signal quality, to a
control entity of the directional antenna.
12. The UAV according to claim 11, wherein the receiver module
comprises a polarization module defining a reference polarization
of the UAV, and wherein the antenna alignment level measurement
report indicates a mismatch between a polarization of the received
alignment signal and said reference polarization.
13. The UAV according to claim 3, further comprising a memory
module arranged to record and store information relating to
received signal quality and/or relating to the antenna alignment
level measurement report.
14. The UAV according to claim 3, wherein the alignment module
comprises a transmitter module arranged to generate and transmit
the alignment signal towards the directional antenna.
15. The UAV according to claim 14, wherein the transmitter module
comprises an on-board directional antenna, the on-board directional
antenna being arranged to be directed towards the directional
antenna.
16. The UAV according to claim 15, further comprising a positioning
module arranged to determine a current direction of the on-board
directional antenna.
17. The UAV according to claim 16, further comprising a control
module arranged to control the direction of the on-board
directional antenna to be directed towards the directional
antenna.
18. The UAV according to claim 14, wherein the transmitter module
comprises a polarization module defining a reference polarization
for transmission of the alignment signal.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 14/785,901, filed Oct. 21, 2015, which is a 371 of
PCT/EP2015/073822, filed Oct. 14, 2015, the disclosures of which
are fully incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to wireless communication
systems, and in particular to antenna alignment of directional
radio antennas for point-to-point communication.
BACKGROUND
[0003] Directional antennas are antennas that concentrate
transmitted and/or received signal power in one or more directions.
Differently from isotropic antennas which have uniform radiation
patterns, and thus the same antenna gain in all directions,
directional antennas tend to have higher antenna gain in some
directions. Directional antennas can therefore be used to improve
communication conditions, but only if correctly aligned with
respect to, e.g., a far-end antenna.
[0004] FIG. 1 shows a schematic view of a point to point
communication system according to prior art. A directional antenna
101 is here shown to be aligned with respect to a far-end
directional antenna 102. An adjustment module 110a, 110b is used to
steer the antenna radiation pattern, i.e., to set 111 the direction
of a main lobe or to adjust an orientation of an antenna radiation
pattern. The adjustment module 110a, 110b may be purely mechanical
or motorized. A motorized adjustment module is possibly also
adjustable by remote control.
[0005] Directional antennas, such as dish antennas, are commonly
used in point-to-point radio links operating at microwave
frequencies. When deploying a point-to-point radio link it is
necessary, due to the narrow main lobes involved, to make sure that
the antennas on each side of the radio link, i.e., near-end and
far-end antennas, are oriented towards each other with sufficient
degree of accuracy. If such alignment is not achieved then the
radio link performance will be degraded due to loss in antenna
system gain.
[0006] A commonly used method for aligning a near-end radio link
antenna with respect to a corresponding far-end antenna is based on
measuring received signal strength at the near-end antenna with
respect to an alignment signal transmission from the far-end
antenna. Consequently, this commonly used method requires that the
far-end antenna is deployed, at least coarsely aligned with respect
to the near-end antenna, and is actively transmitting some type of
alignment signal. The measurement of received signal strength is
often done using a Volt-meter attached to a measurement port of an
alignment signal receiver connected to the near-end antenna. A
technician adjusts orientation of the directional antenna in an
attempt to maximize received signal strength. When the technician
has tested some given range of antenna directions, he selects the
orientation which gave the highest received signal strength, and
the antenna is then considered aligned.
[0007] Of course, a reverse procedure where the far-end antenna is
instead receiving an alignment signal transmission, is also
possible, but not very common.
[0008] A drawback with this commonly used alignment procedure for
aligning radio link antennas is that network roll-out must be
planned carefully and antennas must be aligned in a certain
sequence, since each new antenna alignment procedure requires an
actively transmitting and coarsely aligned antenna on the other
side of the radio link against which to align. Thus, aligning
directional radio antennas is cumbersome and usually involves a lot
of travel between near-end and far-end antennas, in particular
during network roll-out when many directional antennas should be
aligned at the same time.
[0009] Hence, there is a need for improvement of directional
antenna alignment techniques.
SUMMARY
[0010] An object of the present disclosure is to provide systems,
methods and devices which seek to mitigate, alleviate, or eliminate
one or more of the above-identified deficiencies in the art and
disadvantages singly or in any combination and to provide improved
alignment of directional antennas.
[0011] This object is obtained by a system for antenna alignment of
a directional antenna used for wireless communication with respect
to a target location. The system comprises the directional antenna
and an unmanned aerial vehicle (UAV) arranged to be deployed in
relation to the target location. The system is configured for
transmission of an alignment signal between the UAV and the
directional antenna. The system is also configured for measuring a
level of antenna alignment of the directional antenna with respect
to the target location, based on the alignment signal
transmission.
[0012] Hereby, the alignment state of the directional antenna is
not evaluated with respect to a far-end antenna which has been
deployed at the target location, at least coarsely aligned with
respect to the directional antenna, and which is actively
processing some type of alignment signal. Instead, the measuring of
antenna alignment of the directional antenna is made with respect
to the UAV.
[0013] Consequently, the level of alignment of a directional
antenna with respect to a target location can be evaluated
independently of any other antennas in the communication system, in
particular a far-end antenna which has been deployed at the target
location, at least coarsely aligned with respect to the directional
antenna, and which is actively processing some type of alignment
signal.
[0014] Advantageously, alignment of a microwave radio link
directional antenna is hereby performed without first having to
mount and activate transmission from a corresponding far-end
antenna as discussed above. Evaluating alignment of a microwave
radio link directional antenna with respect to a target location is
therefore simplified.
[0015] Advantageously, antenna alignment level, i.e., whether a
current setting of direction of a directional antenna is a
preferred direction or not, with respect to a target location, can
be determined in an efficient fashion for one or more radio links
in a communication system, since there is no dependence on any
other antennas in the communication system during evaluation due to
the use of the UAV.
[0016] According to aspects, the directional antenna comprises an
adjustment module. The adjustment module is arranged for aligning
the directional antenna with respect to the target location based
on the measured level of antenna alignment.
[0017] Hereby, alignment of the directional antenna is achieved
independently of any other antennas, such as a corresponding
far-end antenna of the directional antenna. Thus, by aligning the
directional antenna with respect to the UAV instead of with respect
to a far-end antenna which has been deployed at the target
location, at least coarsely aligned with respect to the directional
antenna, and which is actively processing some type of alignment
signal, the process of antenna alignment is simplified, especially
during network roll-out where many directional antennas are
deployed at the same time.
[0018] Advantageously, a technician does not need to travel back
and forth between antenna sites during antenna deployment and
alignment, which saves time and reduces cost of antenna
deployment.
[0019] Advantageously, many radio links can be installed in
parallel since there is no need for a far-end antenna transmitting
an alignment signal. Cost of network roll-out is also reduced since
there need only be personnel on one site at a time, and the travel
between sites is reduced.
[0020] The object is also obtained by a method for measuring
antenna alignment of a directional antenna used for wireless
communication with respect to a target location. The method
comprises deploying an unmanned aerial vehicle (UAV) in relation to
the target location, transmitting an alignment signal between the
UAV and the directional antenna, and measuring a level of antenna
alignment of the directional antenna with respect to the target
location, based on the alignment signal transmission.
[0021] Hereby, as for the above-mentioned system, the level of
alignment of the directional antenna with respect to the target
location can be evaluated independently of any other antennas in a
communication system, such as a corresponding far-end antenna of
the directional antenna. There is no need for deploying and
activating transmission from a far-end antenna during alignment
evaluation, since evaluation is made with respect to the UAV
instead of with respect to the far-end antenna Thus, evaluating
alignment of a directional antenna with respect to a target
location is simplified.
[0022] According to aspects, the method also comprises aligning the
directional antenna with respect to the target location by
adjusting a direction of the directional antenna in a direction
that improves the measured level of antenna alignment.
[0023] Hereby, alignment of the directional antenna is achieved
independently of any other antennas, such as a corresponding
far-end antenna of the directional antenna. Thus, by aligning the
directional antenna with respect to the UAV instead of with respect
to an already active far-end antenna, the process of antenna
alignment is simplified, especially during network roll-out.
Advantageously, a technician does not need to travel back and forth
between antenna sites during antenna deployment and alignment.
[0024] In addition to the methods there is disclosed herein
computer programs comprising computer program code which, when
executed in a UAV or in connection to a directional antenna, causes
the UAV or directional antenna to execute a method as disclosed
herein.
[0025] The object is furthermore obtained by an unmanned aerial
vehicle (UAV) for aligning a directional antenna used for wireless
communication with respect to a target location. The UAV is
arranged for deployment in relation to the target location, and
comprises an antenna alignment module configured for transmission
of an alignment signal between the UAV and the directional antenna.
The transmission comprises any of transmitting and receiving the
alignment signal. The alignment signal is arranged to indicate a
level of antenna alignment of the directional antenna with respect
to the target location.
[0026] Hereby, as discussed above in connection to the systems and
methods, improved directional antenna alignment is facilitated,
since alignment or evaluation of alignment of a directional antenna
can be made with respect to said UAV rather than with respect to a
far-end antenna which has been deployed at the target location, at
least coarsely aligned with respect to the directional antenna, and
which is actively processing some type of alignment signal.
[0027] It is appreciated that the computer programs and UAVs all
display additional advantages corresponding to advantages mentioned
above in connection to the disclosed systems and methods.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The present disclosure will now be described in more detail
with reference to the appended drawings, where
[0029] FIG. 1 shows a schematic view of a point to point
communication system according to prior art;
[0030] FIGS. 2, 3a, and 3b illustrate antenna alignment of
directional antennas according to embodiments;
[0031] FIGS. 4-6 show schematic views of unmanned aerial vehicles
according to embodiments;
[0032] FIG. 7 shows a flowchart illustrating methods according to
aspects of the present disclosure;
[0033] FIGS. 8-9 illustrate antenna alignment of directional
antennas according to embodiments;
[0034] FIG. 10 shows a flowchart illustrating methods according to
aspects of the present disclosure.
DETAILED DESCRIPTION
[0035] Aspects of the present disclosure will now be described more
fully with reference to the accompanying drawings. The different
devices, computer programs and methods disclosed herein can,
however, be realized in many different forms and should not be
construed as being limited to the aspects set forth herein. Like
numbers in the drawings refer to like elements throughout.
[0036] The terminology used herein is for the purpose of describing
particular aspects of the disclosure only, and is not intended to
limit the invention. As used herein, the singular forms "a", "an"
and "the" are intended to include the plural forms as well, unless
the context clearly indicates otherwise.
[0037] The solution described herein achieves improvements of
antenna alignment and antenna alignment procedures by making
antenna alignment, or evaluation of antenna alignment, with respect
to a target location independent of the remote antenna which is or
will be deployed, at or in a vicinity of the target location. This
independence is achieved by using an unmanned aerial vehicle (UAV)
to align or evaluate alignment against, instead of aligning or
evaluating alignment against a far-end antenna which has been
deployed at the target location, at least coarsely aligned with
respect to the directional antenna, and which is actively
processing some type of alignment signal.
[0038] According to the present teaching, there is no need to first
have a far-end antenna a-priori deployed, coarsely aligned, and
actively transmitting in order to be able to evaluate alignment or
to align a near-end antenna. According to the techniques described
herein, the UAV assumes the role of a far-end antenna which has
been deployed at the target location, at least coarsely aligned
with respect to the directional antenna, and which is actively
processing some type of alignment signal. Evaluation of antenna
alignment state, as well as the process of antenna alignment, is
therefore achieved independently of the far-end antenna, which can
be mounted and activated after antenna alignment has been evaluated
for the near-end antenna.
[0039] According to aspects, UAV herein refers to a drone, or any
other un-manned aerial vehicle which can be flown to and be made to
stay at a target location. In particular, the UAVs discussed herein
may be referred to as unmanned aerial systems (UAS).
[0040] Herein, target location may refer to a position in three
dimensions, or to a flight path as will be further discussed
below.
[0041] Herein, the two directional antennas of a point-to-point
communications link are referred to as near-end antenna and far-end
or remote antenna, respectively. Unless otherwise stated, the
near-end antenna is the antenna for which alignment is evaluated,
or which is aligned, with respect to the far-end or remote antenna
that is or will be deployed at the target location.
[0042] Herein, aligning of two antennas means that antenna
radiation patterns 121a, 121b are matched to each other. For
instance, a directional antenna may have a single main lobe as
illustrated in FIG. 1, in which case the main lobes 121a, 121b
should point towards each other for maximum system antenna gain.
There are also directional antennas that have more than one main
lobe, or an irregular radiation pattern. Such antennas may still
need aligning with respect to a far-end antenna radiation
pattern.
[0043] Some of the main differences between the novel solutions
described herein and prior art can be understood from comparing
FIGS. 1 and 2. Suppose in FIG. 1 that the left-hand side
directional antenna 101 is to be aligned with respect to a target
location X,Y,Z. To align this left-hand side directional antenna
101 according to prior art, one first deploys the right-hand side
antenna 102 at the target location, coarsely directs it towards the
left-hand side antenna, and configures it for transmission (or
reception) of an alignment signal. This requires personnel at the
target location in order to deploy the far-end antenna and to
activate the alignment signal processing. The left-hand side
directional antenna can then be aligned based on the alignment
signal transmission. For instance, alignment can be achieved by
sweeping the antenna main lobe 121a over some range of bearing and
azimuth angles, and determining a direction which, e.g., gives
highest received power. Highest received power may be determined,
e.g., by means of the Volt-meter mentioned above.
[0044] Comparing FIG. 1 to FIG. 2, which illustrates antenna
alignment of directional antennas according to embodiments, the
main difference is absence of the far-end antenna 102. Instead,
there is illustrated in FIG. 2 a system 250 for antenna alignment
of a directional antenna 101 used for wireless communication with
respect to a target location X,Y,Z. The system comprises the
directional antenna 101, and an unmanned aerial vehicle (UAV) 200
arranged to be deployed in relation to the target location X,Y,Z.
The system 250 is configured for transmission of an alignment
signal 211 between the UAV 200 and the directional antenna 101. The
system 250 is also configured for measuring a level of antenna
alignment of the directional antenna 101 with respect to the target
location X,Y,Z, based on the alignment signal transmission.
[0045] So, in FIG. 2 there is no right-hand side antenna 102. The
UAV 200 instead assumes the role of the far-end antenna 102 in FIG.
1. Hence, the level of alignment of the directional antenna 101
with respect to the target location X,Y,Z can be measured
independently of any far-end antenna. As a consequence, the
alignment of the directional antenna 101 with respect to the target
location X,Y,Z can be measured without having any personnel at the
target location, and without having a far-end antenna which has
been deployed at the target location, at least coarsely aligned
with respect to the directional antenna, and which is actively
processing some type of alignment signal as was the case in FIG.
1.
[0046] The UAV 200 being arranged to be deployed in relation to the
target location X,Y,Z is to be construed, according to different
aspects, as any of [0047] the UAV 200 being arranged to be deployed
at the target location X,Y,Z, or as [0048] the UAV 200 being
arranged to be deployed at a location having a known geometrical
relationship with the location of the directional antenna and with
the target location, e.g., along a straight line from the
directional antenna to the target location, or as [0049] the UAV
200 being arranged to be deployed along a flight path in a vicinity
of the target location.
[0050] According to some aspects, the directional antenna 101
comprises an adjustment module 110. The adjustment module 110 is
arranged for aligning the directional antenna 101 with respect to
the target location based on the measured level of antenna
alignment.
[0051] The proposed techniques can be used to evaluate an alignment
state or level of alignment of the directional antenna 101 with
respect to the target location, and also to actually align the
directional antenna with respect to the target location, i.e., to
improve the alignment level of the directional antenna 101 with
respect to the target location X,Y,Z. It is noted that these are
two different, although related, operations.
[0052] The operation of aligning a directional radio antenna
comprises evaluating alignment, possibly followed by adjusting a
direction of the directional antenna to improve on the level of
alignment.
[0053] The operation of evaluating alignment of a directional
antenna with respect to a target location can be performed in its
own right, e.g., in already existing networks as a maintenance
operation, in order to check if some alignment optimization is
warranted.
[0054] The operation of evaluating alignment of a directional
antenna does not necessarily imply that the antenna direction or
orientation will be changed following the evaluation.
[0055] As discussed below in connection to FIGS. 5 and 6, not only
alignment of direction or orientation of the directional antenna
can be measured and/or adjusted, but also polarization alignment.
Polarization of a polarized directional antenna can be adjusted by
rotating the antenna to adjust horizontal and vertical planes of
the directional antenna.
[0056] FIG. 3a illustrates antenna alignment of directional
antennas according to embodiments. Here, the UAV is shown to not be
still at a fixed target location X,Y,Z, but to move along a flight
path 301 in a vicinity of the target location. I.e., the UAV 300,
according to some aspects, is arranged to be deployed along a
flight path 301 in a vicinity of the target location X,Y,Z.
[0057] This type of operation may be preferred in order to evaluate
if a current direction of the directional antenna 101 is a
preferred direction or if some other direction would give better
communication conditions, without actually changing orientation of
the directional antenna. I.e., as the UAV moves along the flight
path, alignment of the directional antenna, keeping the directional
antenna main lobe fixed in a current direction, with respect to the
current location of the UAV can be evaluated. If alignment of the
directional antenna is better when the UAV is at some point in the
flight path other than the target location, then re-alignment or
adjustment of orientation of the directional antenna 101 can be
considered. Advantageously, this operation can be performed during
network operation, since connectivity of the point-to-point radio
link is not jeopardized by changing direction of any of the
directional antennas during alignment evaluation.
[0058] FIGS. 2 and 3a illustrate a UAV deployed at or in a vicinity
of the target location X,Y,Z. However, the UAV can be deployed in
relation to the target location, at some other known location
X',Y',Z' relative to the target location. This concept is
exemplified in FIG. 3b.
[0059] Antenna alignment evaluation and antenna alignment of the
directional antenna 101 with respect to the target location can be
derived or performed, respectively, based on a known relationship
between the actual location of the UAV X',Y',Z', the location of
the directional antenna 101, and the target location X,Y,Z. For
instance, the UAV may be located anywhere along a straight line 310
extending from the location of the directional antenna 101 to the
target location X,Y,Z in order to evaluate a level of alignment of
the directional antenna with respect to the target location. It is
appreciated that a directional antenna 101 aligned with respect to
some point X',Y',Z' on said line will necessarily also be aligned
with respect to the target location X,Y,Z.
[0060] Consequently, throughout this disclosure, deploying the UAV
200, 300, 400 in relation to the target location X,Y,Z is to be
understood, according to different aspects, as deploying the UAV at
the target location X,Y,Z, or deploying the UAV at a location
having a known geometrical relationship with the location of the
directional antenna and with the target location, or deploying the
UAV along a flight path 301 in a vicinity of the target location.
Similarly, the UAV is, according to different aspects, arranged to
be deployed at the target location X,Y,Z, or at a location having a
known geometrical relationship with the location of the directional
antenna and with the target location, or along a flight path in a
vicinity of the target location.
[0061] It is understood that said flight path 301 is, according to
aspects, defined at a point in-between the directional antenna 101
and the target location X,Y,Z, e.g., in a vicinity of a point on
the straight line 310 shown in FIG. 3b.
[0062] Turning now to details of the UAV; FIG. 4 shows a schematic
view of an unmanned aerial vehicle according to embodiments. In
particular, there is shown a UAV 400 for aligning a directional
antenna 101 used for wireless communication with respect to a
target location X,Y,Z. The UAV 400 is arranged for deployment in
relation to the target location X,Y,Z. The UAV comprises an antenna
alignment module 210 configured for transmission of an alignment
signal 211 between the UAV 200 and the directional antenna 101. The
transmission comprises any of transmitting and receiving the
alignment signal. The alignment signal is arranged to indicate a
level of antenna alignment of the directional antenna 101 with
respect to the target location X,Y,Z.
[0063] So, by deploying the UAV 400 illustrated in FIG. 4 at a
target location, a directional antenna 101 can be aligned with
respect to the UAV instead of with respect to a deployed and
actively transmitting far-end antenna. Alternatively, a level of
alignment of a directional antenna with respect to a target
location can be measured by using the UAV 400 illustrated in FIG.
4.
[0064] The level of alignment of the directional antenna 101 with
respect to the target location is evaluated independently of any
other antennas in the communication system, in particular a far-end
antenna which has been deployed at the target location, at least
coarsely aligned with respect to the directional antenna, and which
is actively processing some type of alignment signal.
[0065] Advantageously, antenna alignment level, i.e., whether a
current setting of direction of a directional antenna is a
preferred direction or not, with respect to a target location, can
be determined in an efficient fashion for one or more radio links
in a communication system, since there is no dependence on any
other antennas in the communication system during evaluation due to
the use of the UAV.
[0066] Advantageously, a technician does not need to travel back
and forth between antenna sites during antenna deployment and
alignment, which saves time and reduces cost of antenna
deployment.
[0067] Advantageously, many radio links can be installed in
parallel since there is no need for a far-end antenna transmitting
an alignment signal. Cost of network roll-out is also reduced since
there need only be personnel on one site at a time, and the travel
between sites is reduced.
[0068] As mentioned above, according to some aspects the UAV 400 is
arranged to be deployed at a position having a known relationship
with the target location and with the location of the directional
antenna, as discussed in connection to FIG. 3b above.
[0069] According to aspects, the UAV 400 further comprises a
positioning module 410 arranged to determine a current position of
the UAV 400. This positioning module is, according to aspects,
arranged to determine a position of the UAV by means of, e.g., the
Global Positioning System (GPS) or any other suitable satellite or
terrestrial positioning system.
[0070] According to aspects, the UAV 400 also comprises a control
module 420 arranged to control a position of the UAV 400. The
control module can be used to fly or otherwise re-locate the UAV to
the target location, or to a position having a known geometrical
relationship to the target location and to the directional antenna,
such as a point along the straight line discussed in connection to
FIG. 3b, and to stay or hover at said position or target location,
or to move along the above-mentioned flight path 301.
[0071] According to some aspects, the control module 420 is
arranged to control the position of the UAV 400 based on a current
position of the UAV determined by the positioning module 410 and on
the target location X,Y,Z. Thus, any discrepancy between actual
location of the UAV and target location can be automatically
corrected for by the control module 420. Of course, any discrepancy
between actual location of the UAV and a position having a known
geometrical relationship to the target location, such as
exemplified and discussed in connection to FIG. 3b, can also be
automatically corrected for by the control module 420, given the
location of the directional antenna 101.
[0072] According to some other aspects, the control module 420 is
arranged to control the position of the UAV 400 based on an
external control signal 426 received from a remote location via a
communications module 425 comprised in the control module 420. This
external control signal provides for the possibility of remote
control of the UAV, e.g., by means of remote control radio
transmitter. Thus, a technician may obtain control of the UAV and
deploy the UAV manually at the target location, or at any other
location of his choosing.
[0073] Alignment of a near-end antenna, such as the directional
antenna 101 shown in FIG. 2, using the UAV can be performed in at
least two different ways. Either the directional antenna 101 is
arranged to transmit an alignment signal which the UAV is
configured to receive, or the UAV is configured to transmit an
alignment signal which the directional antenna is configured to
receive.
[0074] In cases where the UAV is configured to receive the
alignment signal, the directional antenna is first coarsely aligned
with respect to the UAV, and then transmission of an alignment
signal from the directional antenna to the UAV is activated. The
UAV receives the alignment signal and evaluates some
characteristics of the received alignment signal, such as received
signal strength which is one example of a measure of signal
quality. The UAV then reports back to the operator how it
experiences the received alignment signal by transmitting an
antenna alignment level measurement report back towards the
directional antenna, or to some other operator location or antenna
control entity. The directional antenna can then be aligned by
trying different directions or orientations until a preferred
direction or orientation is identified based on reports from the
UAV. Cases where the UAV is configured to receive the alignment
signal are discussed below in connection to FIG. 5.
[0075] In cases where the UAV is configured to transmit the
alignment signal to the directional antenna, the directional
antenna is first coarsely aligned with respect to the UAV. The
alignment signal is then received from the UAV via the directional
antenna and some characteristics of the received signal are used as
measure of alignment of the directional antenna. For instance,
received signal strength can be used, in which case a direction of
the directional antenna yielding higher signal strength represents
better alignment than a direction yielding low received signal
strength. The Volt-meter discussed above can be used for the
purpose of measuring received signal strength, given that a
receiver connected to the directional antenna is equipped with a
suitable received signal strength measurement port. The directional
antenna can thus be aligned by trying different directions or
orientations until a preferred direction or orientation is
identified based on the received alignment signal. Cases where the
UAV is configured to transmit the alignment signal are discussed
below in connection to FIG. 6.
[0076] Of course, combinations of the two cases above are also
possible, i.e., the UAV and directional antenna can both transmit
and receive alignment signals. This can be expected to lead to
improvements in alignment accuracy. Furthermore, more than one
signal quality measure can be evaluated in parallel.
[0077] Herein, signal quality may, according to different aspects,
comprise any of measured or estimated; received signal strength,
bit-error rate, packet-error rate, block-error rate, mutual
information between the directional antenna and the UAV, or
log-likelihood ratio.
[0078] To make it easier to visually observe the UAV it, according
to aspects, is equipped with a light source 430 that makes it more
visible during dark operating conditions, e.g., at night.
[0079] FIG. 5 illustrates embodiments where the UAV 500 is
configured to receive the alignment signal 211a.
[0080] Here, the alignment module 210 comprises a receiver module
510 arranged to receive the alignment signal 211a from the
directional antenna 101.
[0081] According to some aspects, the alignment module 210 is
arranged to measure a signal quality of the received alignment
signal. This signal quality may, according to different aspects,
comprise any of measured or estimated; received signal strength,
bit-error rate, packet-error rate, block-error rate, mutual
information between the directional antenna and the UAV, or
log-likelihood ratio.
[0082] According to aspects, the alignment module 210 is arranged
to generate and transmit an antenna alignment level measurement
report 220, based on the measuring of signal quality, to a control
entity of the directional antenna 101. The antenna alignment level
measurement report can be transmitted to the control entity over
various communication channels. Examples of such communication
channels comprise a cellular communications network such as Global
System for Telecommunications (GSM), 3G, or Long Term Evolution
(LTE). It is also possible to use a wireless local area network
implementing, e.g., Wi-Fi, or a proprietary communications link for
transmission of the antenna alignment level measurement report
220.
[0083] According to aspects, the receiver module 510 comprises a
polarization module 511 defining a reference polarization of the
UAV 500. The antenna alignment level measurement report 220 may
then also indicate a mismatch between a polarization of the
received alignment signal 501 and said reference polarization.
Consequently, not only direction-alignment of the directional
antenna can be measured and/or adjusted, but also polarization
alignment. Polarization of a directional antenna can be adjusted by
rotating the directional antenna 101 to adjust horizontal and
vertical planes of the directional antenna 101.
[0084] According to aspects, the UAV 500 further comprises a memory
module 530 arranged to record and store information relating to
received signal quality and/or relating to the antenna alignment
level measurement report.
[0085] This memory module may also be used to transmit the antenna
alignment level measurement report back to the operator. In this
case, the UAV is deployed and makes alignment measurements based on
a received alignment signal. The UAV then stores results of
measurements in the memory module 530, which can be accessed later
by an operator interested in details of the alignment
measurements.
[0086] FIG. 6 illustrates embodiments where the UAV 600 is
configured to transmit the alignment signal 211b.
[0087] Here, the alignment module 210 comprises a transmitter
module 610 arranged to generate and transmit the alignment signal
211b towards the directional antenna 101 by means of an antenna
612.
[0088] The antenna 612 is, according to some aspects, arranged to
radiate signal power in a plurality of directions.
[0089] The antenna 612 is, according to some aspects, an
isotopically radiating antenna.
[0090] According to aspects, the transmitter module 610 comprises
an on-board directional antenna, i.e., the antenna 612 is a
directional antenna, such as a horn antenna. This on-board
directional antenna is arranged to be oriented or directed towards
the directional antenna 101. In this way, the alignment signal can
be transmitted from the UAV 600 to the directional antenna 101
without needlessly interfering with other receivers spatially
separated from the directional antenna 101.
[0091] According to aspects, the positioning module 410 is further
arranged to determine a current direction of the on-board
directional antenna. Such current direction may, e.g., be
determined by means of a compass or other direction-finding
device.
[0092] According to aspects, the control module 420 is further
arranged to control the direction of the on-board directional
antenna to be directed towards the directional antenna 101. Thus,
automatic control of transmit direction by the UAV is achieved.
[0093] According to aspects, the transmitter module 610 comprises a
polarization module 611 defining a reference polarization for
transmission of the alignment signal. Again, not only
direction-alignment of the directional antenna can be measured
and/or adjusted, but also polarization alignment. By means of the
present aspects, the polarization of the directional antenna can be
adjusted with respect to the reference polarization of the UAV. If
more directional antennas are adjusted in polarization with respect
to the same reference polarization, according to aspects with
respect to the same UAV, then the directional antennas can be
expected to be aligned in polarization with respect also to each
other.
[0094] The techniques and concepts discussed above in connection to
FIGS. 2-6 can be described also in terms of methods for measuring
antenna alignment of a directional antenna 101. FIG. 7 shows a
flowchart illustrating such methods. In particular, there is
illustrated a method for measuring antenna alignment of a
directional antenna 101 used for wireless communication with
respect to a target location X,Y,Z. The method comprises deploying
S1 an unmanned aerial vehicle (UAV) in relation to the target
location, transmitting S3 an alignment signal 211 between the UAV
and the directional antenna, and also measuring S5 a level of
antenna alignment of the directional antenna with respect to the
target location, based on the alignment signal transmission.
[0095] It is appreciated that the target location is not
necessarily exactly that of the current or future far-end antenna,
but may also be a position in a vicinity of a current or future
far-end antenna. This was discussed above in connection to FIG.
3b.
[0096] The illustrated method relates to the discussion above in
the context of the system 250 for antenna alignment discussed in
connection to FIGS. 2 and 3, and the different aspects of UAV 300,
400, 500, 600 discussed in connection to FIGS. 3-6.
[0097] In this way, the level of alignment of a directional antenna
with respect to a target location can be evaluated independently of
any other antennas, such as a corresponding far-end antenna of the
directional antenna. Thus, evaluating alignment of a directional
antenna with respect to a target location is simplified.
Advantageously, antenna alignment condition, i.e., whether a
current setting of direction of a directional antenna is a
preferred direction or not, with respect to a target location can
be determined in an efficient fashion for one or more radio links.
Further advantages of the disclosed method have been set out and
discussed above, and will not be discussed here again.
[0098] It is noted that the method set out above comprises
measuring S5 a level of antenna alignment of the directional
antenna with respect to the target location but not actually
aligning the directional antenna. Hence, the method is also
applicable as a diagnostic method for determining a state of
alignment of one or more directional antennas with respect to one
or more target locations. For instance, a UAV can be flown around
in a communication system and used for evaluating radio link
alignment. If some radio link is found to have sub-optimal
alignment, then this can be communicated to a technician.
[0099] Actual aligning of the directional antenna is, according to
aspects, performed following said measurement, i.e., according to
some aspects, the method further comprises aligning S7 the
directional antenna with respect to the target location X,Y,Z by
adjusting a direction or orientation of the directional antenna in
a direction that improves the measured level of antenna
alignment.
[0100] Thus, alignment of the directional antenna is achieved
independently of any other antennas, such as a corresponding
far-end antenna of the directional antenna. By aligning with
respect to the UAV instead of with respect to an already active
far-end antenna, the process of antenna alignment is simplified,
especially during network roll-out. Advantageously, a technician
does not need to travel extensively between antenna sites during
antenna deployment and alignment.
[0101] According to aspects, the measuring comprises recording S50
the measured level of antenna alignment of the directional antenna.
This recording can be achieved by means of the memory module 530
discussed in connection to FIG. 5. By recording the measured level
of antenna alignment, possibly in connection to a current location
of the UAV, an operator can perform a more detailed analysis of
directional antenna alignment by accessing the recorded data.
[0102] According to aspects, the deploying comprises remotely
controlling S11 the position of the UAV in relation to the target
location. Such controlling can be achieved by the control module
420 discussed above, which is arranged to control the position of
the UAV 400 based on an external control signal 426 received from a
remote location via a communications module 425 comprised in the
control module 420. This external control signal provides for the
possibility of remote control of the UAV, e.g., by means of remote
control radio transmitter. Thus, a technician may, e.g., obtain
control of the UAV and deploy the UAV manually in relation to the
target location or at a position relative to the target
location.
[0103] According to aspects, the deploying comprises setting
coordinates S12 for autonomous operation of the UAV to
automatically control the position of the UAV in relation to the
target location. As discussed above, such autonomous operation can
be achieved by use of the control module 420 in combination with
the positioning module 410.
[0104] According to aspects, the deploying further comprises
controlling S13 the position of the UAV along a flight path 301 in
a vicinity of the target location. The flight path 301 was
discussed above in connection to FIGS. 3a and 3b.
[0105] As already mentioned, the solutions for antenna alignment
measurements can be achieved either by transmission of an alignment
signal from the UAV to the directional antenna, or by transmission
of an alignment signal from the directional antenna to the UAV.
With reference to FIG. 7, S31, S32, S51, S52, S53, S54, S71 and S72
mainly relate to the case where the UAV transmits the alignment
signal, while S34, S35, S55, S56, S57, S73 and S74 mainly relate to
the case where the UAV receives the alignment signal
transmission.
[0106] Hence, according to aspects where the UAV is receiving the
alignment signal, the transmitting comprises generating and
transmitting S31 the alignment signal 211a from the directional
antenna 101 to the UAV 500.
[0107] The measuring then, according to some aspects, comprises
receiving S51 the alignment signal from the directional antenna 101
at the UAV 500, and measuring S52 a signal quality of the received
alignment signal.
[0108] The proposed solution is, according to aspects, also
applicable for polarization alignment. Thus, according to some
aspects, the transmitting further comprises transmitting S32 the
alignment signal on a polarization of the directional antenna, and
the measuring comprises measuring S53 a polarization difference
between the polarization of the received alignment signal and a
reference polarization of the UAV. This polarization difference
then serves to indicate a level of polarization alignment between a
current polarization of the directional antenna and the reference
polarization of the UAV, and thus to facilitate polarization
alignment of the directional antenna 101.
[0109] According to some aspects, the method further comprises
generating and transmitting S54 an antenna alignment level
measurement report 220, based on the measuring, from the UAV to a
control entity of the directional antenna. This antenna alignment
level measurement report 220 indicates a level of alignment of the
directional antenna. It can, for instance, be used to improve or
evaluate alignment of the directional antenna. In other words, the
level of alignment of the directional antenna with respect to the
target location can by the present technique be evaluated
independently of any other antennas, such as a corresponding
far-end antenna of the directional antenna. Thus, evaluating
alignment of a directional antenna with respect to a target
location is simplified. Advantageously, antenna alignment
condition, i.e., whether a current setting of direction of a
directional antenna is a preferred direction or not, with respect
to a target location can be determined in an efficient fashion for
one or more radio links.
[0110] Some practical examples of this procedure for generating and
transmitting S54 an antenna alignment level measurement report 220
will be given below in connection to FIGS. 8 and 9.
[0111] According to aspects, the method further comprises receiving
the antenna alignment level measurement report 220 at the control
entity of the directional antenna, and aligning S71 the directional
antenna with respect to the target location based on the received
antenna alignment level measurement report 220.
[0112] This implies that alignment of the directional antenna is
achieved independently of any other antennas, such as a
corresponding far-end antenna of the directional antenna, since the
UAV assumes the role of the far-end antenna. Thus, by aligning with
respect to the UAV instead of with respect to an already active and
coarsely aligned far-end antenna, the process of antenna alignment
is simplified, especially during network roll-out. Advantageously,
a technician does not need to travel extensively between antenna
sites during antenna deployment and alignment.
[0113] According to some aspects, the method further comprises
adjusting S72 a polarization of the directional antenna based on
the antenna alignment level measurement report 220. Consequently,
the method not only provides for alignment of direction, but
according to aspects also of polarization of a directional antenna.
Polarization adjustment was discussed in connection to FIGS. 5 and
6 above.
[0114] According to some aspects, the transmitting comprises
generating and transmitting S34 the alignment signal from the UAV
600 to the directional antenna 101. This transmission S34 is,
according to some aspects, achieved using the transmitter module
610 of the UAV 600 discussed in connection to FIG. 6 above.
[0115] According to some aspects, the measuring comprises receiving
S55 the alignment signal from the UAV 600 at the directional
antenna 101 and measuring S56 a signal quality of the received
alignment signal as function of direction of the directional
antenna 101. Some different examples of signal quality comprises
measured or estimated; received signal strength, bit-error rate,
packet-error rate, block-error rate, mutual information between the
directional antenna and the UAV, or log-likelihood ratio.
[0116] According to some aspects, the transmitting further
comprises transmitting S35 the alignment signal on a reference
polarization of the UAV, and the measuring comprises measuring S57
a polarization difference between the polarization of the
directional antenna and the reference polarization. Again, the
method not only provides for alignment of direction, but according
to aspects also of polarization of a directional antenna.
Polarization adjustment was discussed in connection to FIGS. 5 and
6 above.
[0117] According to some aspects, the method further comprises
aligning S73 the directional antenna with respect to the target
location based on the measured signal quality.
[0118] According to some aspects, the method further comprises
adjusting S74 a polarization of the directional antenna based on
the measured polarization difference.
[0119] According to some aspects, the deploying further comprises
configuring S14 a frequency band of the alignment signal.
Advantageously, antenna alignment can be performed in a frequency
band not intended for use in communication over, e.g., a
point-to-point radio link comprising the directional radio antenna.
Hereby, evaluating antenna alignment, and aligning directional
radio antennas, can be achieved without unnecessarily interfering
with other radio receivers.
[0120] In addition to the methods, there is disclosed herein a
computer program comprising computer program code which, when
executed in a UAV 200, 300, 400, 500, 600 or in connection to a
directional antenna 101, causes the UAV or directional antenna to
execute a method as described above.
[0121] FIGS. 8-9 exemplify antenna alignment of directional
antennas according to embodiments. In particular, examples of the
methods disclosed herein are given where a directional antenna is
aligned with respect to a UAV 200' configured to receive an
alignment signal transmitted from the directional antenna.
[0122] When mounting a directional antenna, such as a directional
microwave radio link dish antenna, the aim is to turn or aim the
antenna in the horizontal plane and in the vertical plane until the
focal point of its main lobe hits the antenna on the far-end. As
discussed above, polarization alignment is also relevant, but will
not be discussed here in connection to FIGS. 8 and 9.
[0123] Traditionally, alignment of radio link antennas has been
done by measuring the signal strength from a sending radio deployed
on the far-end. When the received signal at the near-end antenna
peaks then the near-end antenna is considered aligned. However, as
illustrated and discussed above, advantages are obtained if
alignment is instead performed with respect to a UAV instead of
with respect to a far-end antenna.
[0124] According to the example illustrated in FIG. 8, the UAV,
UAS, or drone, has a wireless device, such as a smart-phone, on
board (a "drone-phone") 810 which is connected to the UAV receiving
antenna via a receiver and a sound generator. The sound generator,
for example an oscillator, is creating a sound that has one or more
properties reflecting the received signal level. Examples of such
sound properties comprise: pitch, volume, intermittent sounds with
variable intervals.
[0125] Before the UAV is sent up and deployed in relation to the
target location, the drone operator (DO) uses the drone-phone to
call up an installation technician (IT) that shall perform the
antenna alignment. The IT answers the call 820 and listens to the
sound signal from the drone-phone using ear-plugs or a head-set so
that he or she can work with both hands free.
[0126] Compared to the traditional way of aligning antennas using a
volt-meter connected to the directional antenna, the IT phone
replaces the volt meter for measuring the received radio signal
strength and therefore also the current level of alignment.
[0127] FIG. 10 shows a flowchart illustrating methods according to
aspects of the present disclosure.
[0128] If the far-end site is not yet built and a UAV is used then
the Installation Technician (IT) and the Drone Operator (DO) may
operate according to the following alignment procedure, with
reference to FIG. 10; [0129] The DO configures A1 the UAV with the
GPS coordinates for the future far-end antenna including altitude;
[0130] The DO uses A2 the drone-phone to call up the IT; [0131] The
DO sends up A3 the UAV to the prepared location and makes sure that
the UAV is oriented so the cone antenna is directed towards the
aligning antenna; [0132] The IT makes a rough alignment A4 of the
directional antenna towards the UAV using a compass and (if
possible) visual sighting of the UAV; [0133] The IT listens to the
sound signal in his phone sent from the drone-phone and adjusts the
antenna direction until the sound has peaked; [0134] Now the
alignment is done. The IT hangs up the call from the drone-phone,
calls up the DO and tells him that the alignment is
accomplished.
[0135] To make it easier to see the UAV it, according to aspects,
is equipped with a light source that makes it more visible, as was
discussed in connection to FIG. 4.
[0136] Turning back to FIG. 9, instead of sending the UAV's
received signal level as a sound over a phone-call, the UAV could
have a processor that converts the signal level to digital
information sent to the drone-phone 910. In this case the
drone-phone can have an application, or `app`, that communicates
with a corresponding app on the ITs phone 920. In this case the IT
can read the current signal level in, e.g., units of dBm, on the
phone's display. This phone can also highlight the screen (and give
a sound signal) when the level reaches a target value.
[0137] The various aspects of the methods described herein are
described in the general context of method steps or processes,
which may be implemented in one aspect by a computer program
product, embodied in a computer-readable medium, including
computer-executable instructions, such as program code, executed by
computers in networked environments. The computer-readable medium
may e.g. be a non-transitory computer-readable medium. A
computer-readable medium may include removable and non-removable
storage devices including, but not limited to, Read Only Memory
(ROM), Random Access Memory (RAM), compact discs (CDs), digital
versatile discs (DVD), etc. Generally, program modules may include
routines, programs, objects, components, data structures, etc.,
that perform particular tasks or implement particular abstract data
types. Computer-executable instructions, associated data
structures, and program modules represent examples of program code
for executing steps of the methods disclosed herein. The particular
sequence of such executable instructions or associated data
structures represents examples of corresponding acts for
implementing the functions described in such steps or
processes.
* * * * *