U.S. patent application number 14/779623 was filed with the patent office on 2016-02-25 for a radio antenna alignment tool.
This patent application is currently assigned to Telefonaktiebolaget L M Ericsson (publ). The applicant listed for this patent is TELEFONAKTIEBOLAGET L M ERICSSON (PUBL). Invention is credited to Jonas Hansryd, Christina Larsson, Bengt-Erik Olsson.
Application Number | 20160056525 14/779623 |
Document ID | / |
Family ID | 48050003 |
Filed Date | 2016-02-25 |
United States Patent
Application |
20160056525 |
Kind Code |
A1 |
Hansryd; Jonas ; et
al. |
February 25, 2016 |
A Radio Antenna Alignment Tool
Abstract
A radio antenna alignment tool (100) for aligning a first
antenna with respect to at least a second antenna is disclosed. The
tool comprises a sensor unit (120) disposed in connection to the
first antenna (110) comprising means to determine a present
direction of the first antenna (110). The radio antenna alignment
tool (100) further comprises guiding means (130) adapted to
receive, on a first input port, the present direction of the first
directive antenna (110) from the sensor unit (120). The guiding
means (130) is further arranged to indicate to a user at least one
of: the present direction of the first directive antenna (110), the
location of the second antenna, and a preferred direction of the
first directive antenna, where said preferred direction of the
first directive antenna is determined in order to maximize a signal
quality metric for communication between the first directive
antenna and at least the second antenna. The tool facilitates the
alignment of the first directive radio antenna without the user
having direct visual contact with the far end antenna.
Inventors: |
Hansryd; Jonas; (Goteborg,
SE) ; Larsson; Christina; (Molndal, SE) ;
Olsson; Bengt-Erik; (Hovas, SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TELEFONAKTIEBOLAGET L M ERICSSON (PUBL) |
Stockholm |
|
SE |
|
|
Assignee: |
Telefonaktiebolaget L M Ericsson
(publ)
Stockholm
SE
|
Family ID: |
48050003 |
Appl. No.: |
14/779623 |
Filed: |
April 2, 2013 |
PCT Filed: |
April 2, 2013 |
PCT NO: |
PCT/EP2013/056934 |
371 Date: |
September 24, 2015 |
Current U.S.
Class: |
342/359 |
Current CPC
Class: |
H01Q 15/08 20130101;
H04B 17/12 20150115; H01Q 1/125 20130101; H01Q 17/001 20130101;
H01Q 1/1257 20130101; H01Q 3/08 20130101 |
International
Class: |
H01Q 1/12 20060101
H01Q001/12 |
Claims
1-18. (canceled)
19. A radio antenna alignment tool for aligning a first directive
antenna with respect to at least a second antenna, the radio
antenna alignment tool comprising: a sensor unit disposed connected
to the first directive antenna, the sensor unit comprising: means
to determine a present direction of the first directive antenna; an
interface on which sensor information comprising the present
direction can be accessed, guiding means configured to: receive, on
a first input port, the present direction of the first directive
antenna from the interface of the sensor unit; indicate to a user
at least one of: the present direction of the first directive
antenna, the location of the second antenna, and a preferred
direction of the first directive antenna; wherein the preferred
direction of the first directive antenna is determined in order to
maximize a signal quality metric for communication between the
first directive antenna and at least the second antenna.
20. The radio antenna alignment tool of claim 19: wherein the
signal quality metric comprises at least one parameter of: a
received signal power; a mean squared error; a measure of frequency
selectivity; a bit error rate; a frame error rate; a
multiple-antenna communication channel rank; and a multiple-antenna
communication channel condition number; wherein the parameter is
measured based on a signal received at the first directive antenna
from at least the second antenna.
21. The radio antenna alignment tool of claim 19, wherein the
preferred direction of the first directive antenna is determined in
order to maximize the signal quality metric for communication
between the first directive antenna and the second antenna in
non-line-of-sight (NLOS) conditions.
22. The radio antenna alignment tool of claim 19, wherein the
sensor unit further comprises at least one of: a camera; a
positioning system unit; a three-dimensional compass; and a radar
transceiver unit.
23. The radio antenna alignment tool of claim 19: wherein the
sensor unit comprises a camera adapted to capture an image; wherein
the guiding means is configured to determine the preferred
direction of the first directive antenna by means of processing
image data received from the sensor unit.
24. The radio antenna alignment tool of claim 19: wherein the
guiding means further comprises a processing circuit configured to
receive at least one of: sensor information data from the sensor
unit on the first port of the guiding means; received signal
strength data from a radio receiver unit connected to the first
directive antenna; geographic data; wherein the geographic data
comprises at least one of: building coordinates; coordinates of the
first directive antenna; coordinates of the second antenna; and
geometry of buildings; wherein the processing circuit is configured
to determine the preferred direction based on the received
data.
25. The radio antenna alignment tool of claim 19, wherein the
guiding means further comprises a display unit configured to
display at least one of: a first indicator indicating the present
direction of the first directive antenna; a second indicator
indicating the location of the second antenna; a third indicator
indicating the preferred direction of the first directive
antenna.
26. The radio antenna alignment tool of claim 25, wherein the
display unit is further configured to display an image showing a
camera view as seen from the first directive antenna, in the
current direction of the first directive antenna.
27. The radio antenna alignment tool of claim 19: wherein the radio
alignment tool is configured to determine a plurality of preferred
directions of the first directive antenna with respect to the
second antenna, the preferred directions being suitable for
communication over an non-line-of-sight (NLOS) communication
channel where an obstacle blocks a line-of-sight (LOS), between the
first directive antenna and the second antenna, wherein the radio
alignment tool is configured to determine the plurality of
preferred directions by evaluating a plurality of alternative
propagation paths, including propagation paths with reflection and
propagation paths with diffraction.
28. The radio antenna alignment tool of claim 19: further
comprising an emitter unit connected to the second antenna, the
emitter unit being configured to transmit a known signal; wherein
the sensor unit is configured to receive the known signal and to
measure the power of the received known signal; wherein the guiding
means is configured to: receive the power measurement value from
the sensor unit; indicate the power measurement value to a user;
determine the preferred direction of the first directive antenna
based on the power measurement value.
29. The radio antenna alignment tool of claim 28: wherein the
emitter unit and sensor unit each comprise first and second antenna
arrays, respectively; wherein the emitter unit is configured to
transmit a known narrow-beam signal in a pre-determined sequence
over a first pre-determined range of antenna array beam transmit
directions; wherein the sensor unit is configured to measure
received signal power over a second pre-determined range of antenna
array beam receive directions, wherein the sensor unit is
configured to communicate the power measurements and corresponding
receive beam directions to the guiding means; wherein the guiding
means is configured to: store the power measurements together with
the corresponding receive beam directions in a memory; select a
suitable direction of the first directive antenna based on the
received power measurements and corresponding receive beam
directions.
30. A method for aligning a first directive antenna and at least a
second directive antenna in non-line-of-sight (NLOS) communication
conditions, the method comprising: sensing a current direction of
the first directive antenna; determining a preferred direction of
the first directive antenna, the preferred direction maximizing a
signal quality metric for communication between the first and
second antennas; presenting, to a user, at least one of: the
current direction of the first directive antenna; the location of
the second directive antenna; the preferred direction of the first
directive antenna.
31. The method of claim 30: wherein the signal quality metric
comprises at least one parameter of: a received signal power; a
mean squared error; a measure of frequency selectivity; a bit error
rate; a frame error rate; a multiple-antenna communication channel
rank; a multiple-antenna communication channel condition number;
wherein the parameter is measured based on a signal received at the
first directive antenna from at least the second antenna.
32. The method of claim 30, wherein the sensing the current
direction of the first directive antenna comprises sensing at least
one of: a camera image as seen from the first directive antenna;
coordinates of the first directive antenna; coordinates of the
second directive antenna.
33. The method of claim 30: wherein an emitter is connected to the
second directive antenna and configured to transmit a known radio
signal; wherein the sensing the current direction of the first
directive antenna comprises measuring a received signal power by
means of a radio receiver unit, connected to the first directive
radio antenna, that is configured to receive the known radio
signal.
34. The method of claim 33, wherein the determining a preferred
direction of the first directive antenna comprises determining the
preferred direction to maximize the signal quality metric based on
at least one of: the result from the sensing the current direction
of the first directive antenna; a measurement of received signal
power; map information, the map information comprising
pre-determined building coordinates, antenna unit coordinates, and
building geometry.
35. A computer program product stored in a non-transitory computer
readable medium for assisting in aligning a first directive antenna
with respect to at least a second directive antenna in
non-line-of-sight (NLOS) communication conditions, the computer
program product comprising software instructions which, when run on
one or more processors of a mobile device, causes the mobile device
to: sense a current direction of the first directive antenna;
determine a preferred direction of the first directive antenna, the
preferred direction maximizing a signal quality metric for
communication between the first and second antennas; present, to a
user, at least one of: the current direction of the first directive
antenna; the location of the second directive antenna; the
preferred direction of the first directive antenna.
36. A mobile device for assisting in aligning a first directive
antenna with respect to at least a second directive antenna in
non-line-of-sight (NLOS) communication conditions, the mobile
device comprising: a processor, a non-transitory computer readable
medium storing software instructions, the software instructions
configured to, when run on the processor, cause the mobile device
to: sense a current direction of the first directive antenna;
determine a preferred direction of the first directive antenna, the
preferred direction maximizing a signal quality metric for
communication between the first and second antennas; present, to a
user, at least one of: the current direction of the first directive
antenna; the location of the second directive antenna.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to alignment of directive
radio antennas.
BACKGROUND ART
[0002] Directive radio antennas are antennas which concentrate
radiated signal energy in one or several pre-determined directions
in order to increase the transmitted signal power in that or those
directions. The direction in which the most energy is radiated,
i.e., the direction with highest antenna gain, is often referred to
as the main lobe of the radio antenna. Due to reciprocity, antenna
gain characteristics for transmission and reception are often
similar in terms of antenna directivity. I.e., the direction of the
transmit main lobe as a rule coincides with the direction of the
receive main lobe. Examples of directive radio antennas comprise
disc antennas, horn antennas, and various forms of antenna
arrays.
[0003] Directive antennas are an integral part in microwave radio
links used for point to point communication, e.g., in cellular
backhaul applications. Microwave links as a rule have highly
directive antennas at both ends of the radio link. Due to the high
directivity, correct alignments of antennas are crucial in order to
reach expected performance in a radio link application, as an
erroneous alignment will adversely affect system gain. In radio
links, and also throughout this text, the directive antenna which
is closest to an observer is referred to as the near end antenna,
while the second antenna is referred to as the far end antenna.
Hence, the antenna which is being aligned is often the near end
antenna, which is being aligned with respect to the far end
antenna.
[0004] When a directive radio antenna is deployed in line-of-sight,
LOS, conditions, meaning that there is a clear line of sight
between the near end antenna and far end antenna, antenna alignment
can be done by visual means, i.e., by visually observing the
position of the far end antenna and aligning accordingly. However,
in case the communication system is deployed in non-line-of-sight,
NLOS, conditions, meaning that the LOS is in some way obstructed,
coarse radio antenna alignment can be complicated since the view of
the far end antenna is obstructed. In such cases it can be
difficult to know how to align the antenna since the direction of
the far end antenna is unknown. NLOS radio link deployment is
regularly needed for backhaul of small and dense cell deployments
in urban cellular networks.
[0005] Thus, in order to facilitate quick and cost effective
installation of directive radio antennas in NLOS conditions,
improvements in radio antenna alignment tools and procedures are
needed.
SUMMARY
[0006] An object of the present disclosure is to provide a method
and a tool for alignment of radio antennas in non-line-of-sight,
NLOS, conditions which seeks 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 a quick
and cost effective means for directive antenna alignment in NLOS
conditions.
[0007] This object is obtained by a radio antenna alignment tool
for aligning a first directive antenna with respect to at least a
second antenna. The radio antenna alignment tool comprises a sensor
unit disposed in connection to the first directive antenna, the
sensor unit comprising means to determine a present direction of
the first directive antenna, as well as an interface on which
sensor information comprising the present direction can be
accessed.
[0008] The radio antenna alignment tool further comprises guiding
means adapted to receive, on a first input port, the present
direction of the first directive antenna from the interface of the
sensor unit. The guiding means is also arranged to indicate to a
user at least one of: the present direction of the first directive
antenna, the location of the second antenna, and a preferred
direction of the first directive antenna, where said preferred
direction of the first directive antenna is determined in order to
maximize a signal quality metric for communication between the
first directive antenna and at least the second antenna.
[0009] Hence, a user of the tool can look to the guiding means
during antenna alignment in order to discern information which
facilitates the alignment of the first directive radio antenna
without the user having direct visual contact with the far end
antenna towards which the first directive antenna should be
directed. Thus a quick and cost effective means for directive
antenna alignment in NLOS conditions is provided.
[0010] According to an aspect, said preferred direction of the
first directive antenna is determined in order to maximize the
signal quality metric for communication between the first directive
antenna and the second antenna in non-line-of-sight, NLOS,
conditions.
[0011] According to an aspect, the sensor unit further comprises at
least one out of a camera, a positioning system unit, a
three-dimensional compass, and a radar transceiver unit.
[0012] According to an aspect, the camera is adapted to capture an
image, and the guiding means is arranged to determine the preferred
direction of the first directive antenna by means of processing
image data received from the sensor unit.
[0013] According to an aspect, the guiding means also comprises a
processing unit arranged to receive at least one out of: sensor
information data from the sensor unit on a first port of the
guiding means, received signal strength data from a radio receiver
unit connected to the first directive antenna, and geographic data,
which geographic data comprises at least one out of: building
coordinates, coordinates of the first directive antenna,
coordinates of the second antenna, and geometry of buildings. The
processing unit is adapted to determine the preferred direction
based on said received data.
[0014] According to an aspect, the guiding means also comprises a
display unit adapted to display at least one out of: a first
indicator indicating the present direction of the first directive
antenna, a second indicator indicating the location of the second
antenna, and a third indicator indicating the preferred direction
of the first directive antenna, thus facilitating alignment of the
first directive antenna.
[0015] According to an aspect, the display unit is further adapted
to display an image showing a camera view as seen from the first
directive antenna, in the current direction of the first directive
antenna.
[0016] According to an aspect, the radio antenna alignment tool is
further adapted to determine a plurality of preferred directions of
the first directive antenna with respect to the second antenna,
which preferred directions are suitable for communication over an
NLOS communication channel where an obstacle blocks the
line-of-sight, LOS, between the first directive antenna and the
second antenna, by evaluating a plurality of alternative
propagation paths, including propagation paths with reflection and
propagation paths with diffraction.
[0017] According to an aspect, the radio antenna alignment tool
further comprises an emitter unit disposed in connection to the
second antenna. The emitter unit is arranged to transmit a known
signal. The sensor unit is adapted to receive said known signal, as
well as to measure the power of the received known signal. The
guiding means is arranged to receive said power measurement value
from the sensor unit, and to indicate said power measurement value
to a user, as well as to determine the preferred direction of the
second directive antenna based on said power measurement value.
[0018] According to an aspect, the emitter unit and sensor unit
also comprises first and second antenna arrays, respectively. The
emitter unit is arranged to transmit a known narrow-beam signal in
a pre-determined sequence over a first pre-determined range of
antenna array beam transmit directions. The sensor unit is arranged
to measure received signal power over a second pre-determined range
of antenna array beam receive directions, as well as to communicate
said power measurements and corresponding receive beam directions
to the guiding means. The guiding means is arranged to store said
power measurements together with the corresponding receive beam
directions in a memory, and to select a suitable direction of the
first directive antenna based on said received power measurements
and corresponding receive beam directions.
[0019] The above stated object is also obtained by means of a
method for aligning a first directive antenna and at least a second
antenna in non-line-of-sight, NLOS, communication conditions. The
method comprising the steps of; [0020] Sensing a current direction
of the first directive antenna, [0021] Determining a preferred
direction of the first directive antenna, which preferred direction
maximizes a signal quality metric for communication between the
first and second antenna, [0022] Presenting to a user at least one
out of: the current direction of the first directive antenna, the
location of the second directive antenna, the preferred direction
of the first directive antenna.
[0023] Thus, the disclosed tool and method for antenna alignment
will simplify the installation of directive radio antennas used,
e.g., in wireless NLOS backhaul radio links. By reducing alignment
time, and also relaxing requirements on installer expertise, an
efficient and cost effective roll-out of radio link networks is
facilitated. These are important benefits, especially when it comes
to the deployment of radio link backhaul for small and dense cell
deployment in urban cellular networks.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The present technique will be described in more detail in
the following, with reference to the appended drawings, in
which
[0025] FIG. 1 shows a first aspect of a radio antenna alignment
tool, and
[0026] FIG. 2 shows a second aspect of a radio antenna alignment
tool, and
[0027] FIG. 3 shows a display unit, and
[0028] FIG. 4 shows a third aspect of a radio antenna alignment
tool, and
[0029] FIG. 5 shows a flowchart of a method of the disclosure.
DETAILED DESCRIPTION
[0030] Aspects of the present disclosure will be described more
fully hereinafter with reference to the accompanying drawings, in
which different aspects of the disclosure are shown. The present
technique may, however, be embodied in many different forms and
should not be construed as being limited to those aspects set forth
herein. Rather, these aspects are provided so that this disclosure
will be thorough and complete, and will fully convey the scope of
the technique to those skilled in the art. Like reference signs
refer to like elements throughout the description.
[0031] FIG. 1 shows a first aspect of a radio antenna alignment
tool 100. The alignment tool 100 comprises a sensor unit 120 which
has been attached to a first directive antenna 110. The antenna 110
shown in FIG. 1 is a disc antenna, but other types of directive
antennas are possible to use, e.g., a horn antenna or an antenna
array. The antenna 110 can also be part of a group of antennas
constituting a multiple antenna system, e.g., a multiple-input
multiple-output, MIMO, antenna system. The first directive antenna
110 is suitably attached to fixed infrastructure, here shown as a
mast pole 150, by means of an attachment device 140. The attachment
device 140 suitably allows for changing the direction of the
antenna 110. Thus, by means of the attachment device 140 the
alignment of the directive antenna 110 can be changed, either
manually or automatically by means of, e.g., an electric motor.
[0032] The first directive antenna 110 is directive in the sense
that it transmits and receives electromagnetic energy with higher
gain in some directions compared to other directions. The direction
of largest gain is referred to as the main lobe of the antenna.
Henceforth, when referring to a direction, e.g., a preferred
direction, in relation to a directive antenna, it is the direction
of the antenna main lobe which is referred to.
[0033] The sensor unit 120 comprises means to determine in which
direction the first directive antenna 110 is directed. As will be
explained in more detail below, the sensor unit 120 in aspects of
the tool 100 comprises a number of different sensors, sensing a
wide range of information which could be of assistance to a user of
the tool 100 in the alignment process. The sensor unit 120 further
comprises an interface 121 on which sensor information can be
accessed. This interface 121 is not necessarily an electrical or
optical data interface: A display where a user can read information
visually is used as interface 121 in various aspects of the tool
100.
[0034] The tool 100 further comprises guiding means 130 connected
to the interface 121 of the sensor unit 120 via a first port 131 of
the guiding means 130. The guiding means 130 suitably comprises
information processing and visualization means in order to assist a
user of the tool with aligning the first directive radio antenna
110. Aspects of the guiding means 130 will be described in more
detail in connection to FIG. 3 below.
[0035] Consequently, FIG. 1 shows a radio antenna alignment tool
100 for aligning a first directive antenna 110 with respect to at
least a second antenna. The radio antenna alignment tool 100
comprises a sensor unit 120 disposed in connection to the first
directive antenna 110, the sensor unit 120 comprising means to
determine a present direction of the first directive antenna 110,
as well as an interface 121 on which sensor information comprising
the present direction can be accessed.
[0036] The radio antenna alignment tool 100 further comprises
guiding means 130 adapted to receive, on a first input port 131,
the present direction of the first directive antenna 110 from the
interface 121 of the sensor unit 120. The guiding means 130 is also
arranged to indicate to a user at least one of: the present
direction of the first directive antenna 110, the location of the
second antenna, and a preferred direction of the first directive
antenna 110, where said preferred direction of the first directive
antenna 110 is determined in order to maximize a signal quality
metric for communication between the first directive antenna 110
and at least the second antenna.
[0037] Hence, a user of the system employs the guiding means 130 in
order to discern crucial information needed to align the first
directive antenna 110 without having direct visual contact with the
far end antenna towards which the first directive antenna 110
should be directed. In fact, a user of the tool 100 does not even
need to know approximately where the far end antenna is located as
this information is communicated to him via said guiding means
130.
[0038] It should be noted that the preferred direction of the first
directive antenna 110 is not necessarily directly towards the far
end antenna. The preferred direction depends on propagation
conditions in the particular communications scenario. Thus, the
preferred direction can be towards a point where a strong
reflection of radio energy occurs, or towards a point where a
diffraction of radio energy occurs, or even towards a point which
is preferred due to a combination of propagation phenomena working
together to make the direction a preferred direction.
[0039] In aspects of the tool 100, the signal quality metric
comprises an estimate or measure of received signal power, or,
alternatively, an estimate or measure of received signal energy.
The received signal in question being received by the first
directive antenna 110 from the far end antenna or alternatively
from a third antenna located in the immediate vicinity of the far
end antenna.
[0040] Concrete examples of the signal quality metric, which metric
is maximized by pointing the first directive antenna 110 in the
preferred direction, will be given below. This signal quality
metric takes on different forms in various aspects of the tool 100,
depending on, e.g., the communication system hardware. Signal
quality metrics are in different aspects of varying complexity
ranging from low complexity metrics such as received signal
strength, RSS, i.e., received signal energy or received signal
power, to more advanced signal quality metrics such as mutual
information metrics and other similar information theoretic
measures of received signal quality.
[0041] Signal quality metrics based on the detection of a
communication signal, e.g., a quadrature amplitude modulated, QAM,
signal, by means of a communications receiver are of course also
possible to use. Examples of such signal quality metrics include
the mean squared error, MSE, and the signal to noise ratio, SNR, as
well as the amount of frequency selectivity in the propagation
channel. MSE can be measured as the squared difference between a
received signal and a detected or a known signal, SNR can be
measured by comparing received signal power to receiver noise
power, and the frequency selectivity of a propagation channel can
be measured by analysis of the filter transfer function of an
equalizer comprised in the receiver. The bit error rate, BER, and
frame error rate, FER, in a detected communication signal are of
course viable signal quality metrics as well. It should be noted
that the determining of above-mentioned signal quality metrics can
be facilitated by a transmission of known pilot symbols from the
far end to the near end installations.
[0042] Thus, according to an aspect, the signal quality metric used
for aligning the first directive antenna 110 in the preferred
direction comprises at least one out of a received signal power, a
mean squared error, a measure of frequency selectivity, a bit error
rate, and a frame error rate, measured on a signal received by the
first directive antenna 110 from at least the second antenna.
[0043] According to an aspect, the preferred direction of the first
directive antenna 110 is determined in order to maximize a signal
quality metric for communication between the first directive
antenna 110 and the second antenna in non-line-of-sight, NLOS,
conditions. An example of this is if the communication system is a
multi-antenna communication system. In such cases the communication
channel rank or condition number is likely to be of importance.
Hence, channel quality metrics related to multi-antenna systems,
e.g., multiple-input multiple-output, MIMO, systems, such as
channel rank and channel condition number, is in aspects of the
tool 100 comprised in the signal quality metric.
[0044] A common trait in all signal quality metrics mentioned above
which can be considered for use in aspects of the disclosed system
100 is that they in some way indicate the quality or expected
quality of the signal received at the first directive antenna 110,
or at a second far end antenna. Thus, the better the antenna
alignment is, the higher the signal quality metric becomes.
[0045] FIG. 2 shows a second aspect of a radio antenna alignment
tool 200. A non-line-of-sight, NLOS, radio link is to be
established between a far end radio unit 240 and a near end radio
unit 230, which near end radio unit 230 transmits and receives by
means of a first directive radio antenna 110. In order to have the
radio link functional, the first directive radio antenna 110 must
be carefully aligned such as to enable communication between near
end 230 and far end 240 radio units. A sensor unit 120 is disposed
in connection to the first directive radio antenna 110. In this
aspect of the tool 200, the sensor unit 120 comprises a plurality
of sensors: A positioning unit 222, a 3D-compass 221, a radar
transceiver unit 223, and a camera 220.
[0046] The positioning unit 222 is suitably a global positioning
system, GPS, receiver, a Galileo positioning system receiver, a
Glonass receiver, or similar positioning system receiver. The
positioning system is arranged to determine the coordinates, i.e.,
the position, of the first directive antenna 110. Information from
said sensors is made available, i.e., is adapted to be transmitted,
via the sensor unit interface 121. Thus, by connecting to the
interface 121, the coordinates of the near end antenna, the 3D
direction of the near-end antenna, a radar image of the surrounding
environment, and an image of the surrounding environment can be
accessed.
[0047] The radio antenna alignment tool 200 further comprises
guiding means 130. The guiding means 130 accesses the sensor
information listed above by connecting to the sensor unit interface
121 via a first input port 131 of the guiding means 130. The
guiding means 130 also comprises a second input port 212, on which
second input port 212 the guiding means is arranged to receive
signal strength data from the near end radio unit 230, i.e., a
measure of the signal strength of a signal received from the far
end radio unit 240. Further, the guiding means 130 comprises a
third input port 211 on which external input data is received.
Examples of such external input data are geographic data, which
geographic data in different aspects of the tool 200 comprises at
least one out of: building coordinates, pre-determined coordinates
of the first directive antenna 110, pre-determined coordinates of
the far end radio unit 240, pre-determined coordinates of the
antenna of the far end radio unit, and geometry of buildings in the
vicinity of the radio link.
[0048] The inputs to the first 131, second 212, and third 211 input
ports are received by a processing unit 210. The processing unit
210 is arranged to process the sensor information and external data
in order to determine a preferred direction of the first directive
radio antenna 110. The preferred direction is in different aspects
of the tool 200 determined by interpolation between geographical
coordinates, or by means of propagation models of the surrounding
environment.
[0049] Thus, FIG. 2 shows an aspect of the tool 200 wherein the
sensor unit 120 comprises at least one out of a camera 220, a
positioning system unit 222, a two-dimensional compass (not shown
in FIG. 2), a three-dimensional compass 221, and a radar
transceiver unit 223.
[0050] The processing unit 210 is connected to a display unit 132,
which will be described in detail in connection to FIG. 3
below.
[0051] According to an aspect of the tool 200, the sensor unit 120
comprises a camera 220 adapted to capture an image, and the guiding
means 130 is arranged to determine the preferred direction of the
first directive antenna 110 by means of processing image data
received from the sensor unit 120. A number of image processing
techniques can be employed for this purpose. As an example, the
location in the captured image of the far end antenna is estimated
based on an input location of the far end antenna, or simply input
by the user. The preferred direction is then determined by means of
interpolation between the location in the image of the far end
antenna and the location of the camera 220.
[0052] Thus, the disclosed alignment tool 200 can aid in
visualizing the current alignment of the first directive radio
antenna 110, and supports the installer by determining and
visualizing a preferred direction of the first directive antenna
110, e.g., by projecting an aiming sight indicating the preferred
direction or the location of the far end antenna onto the captured
image. The location of the far end antenna can be programmed into
the guiding means 130 prior to installation or down-loaded on-site.
The user of the tool 200 can then change the alignment of the first
directive antenna 110 such that the current direction of the
antenna coincides with the preferred direction.
[0053] According to another aspect, the guiding means 130 comprises
a processing unit 210 arranged to receive at least one out of:
sensor information data from the sensor unit 120 on the first port
131 of the guiding means 130, received signal strength data from a
radio receiver unit 230 connected to the first directive antenna
110, and geographic data. The geographic data comprises at least
one out of: coordinates of surrounding buildings, coordinates of
the first directive antenna 110, coordinates of the second antenna,
and information pertaining to the geometry of surrounding
buildings.
[0054] The processing unit 210 is in aspects of the tool 200
adapted to determine the preferred direction based on said received
data. This means that the processing unit 210 can determine the
geographical and electromagnetical layout of the current link
between the first directive antenna 110 and the second antenna.
Then, based on this information the processing unit 210 determines
a direction in which to direct the near end antenna in order to
maximize a signal quality metric. An example of this is to apply
ray-tracing techniques based on an emitted signal from the far end
antenna, which simulates the propagation of the emitted signal
based on the propagation environment, in order to determine the
preferred direction of the near end antenna in which the most
signal energy is inbound. A less complex alternative aspect is to,
as mentioned above, apply a linear interpolation between the
position of the far end antenna and the position of the near end
antenna, and to base the preferred direction upon said
interpolation.
[0055] In aspects of the tool, the determining of preferred
direction is an iterative process, i.e., the guiding means 130
instructs the user to change the current direction upon which the
sensor unit 120 makes additional measurements of e.g., received
signal power. In this way a range of directions can be scanned in
order to determine which direction that gave the optimum signal
quality metric. The guiding means 130 suitably then instructs the
user to direct the near end antenna, i.e., the first directive
antenna 100, in the direction of highest signal quality metric.
[0056] Thus, input data to the processing unit 210 is first used to
determine a coarse alignment by means of image processing and
geometrical methods, following which a fine alignment is
performed.
[0057] FIG. 3 shows a display unit 132 suitable for use in a
guiding means. The display unit 132 can perform the function of
interfacing with a user of the radio antenna alignment tool 100. In
this aspect of the display unit 132, the display unit 132 comprises
a display or screen 332 on which an image as seen from the camera
220 of the sensor unit 120 can be displayed. Alternatively, in
other aspects of the display unit 132, no camera image is displayed
on the screen 332, which instead shows a background image, possibly
monochrome.
[0058] At least three indicators are in aspects displayed to the
user on the screen 332; a first indicator 333 indicating the
present direction of the first directive antenna 110, a second
indicator 334 indicating the location of the second antenna, and a
third indicator 335 indicating a preferred direction of the first
directive antenna 110.
[0059] Thus, a user of the tool can look to the display unit 132
and receive information which facilitates the alignment of the
first directive radio antenna 100. In this way, the user of the
tool will know at least approximately where the far end radio unit
and far end antenna unit is located, and how to direct the first
directive antenna 110 to achieve radio link connectivity, even
though there is no clear line of sight between the near end
installation and the far end installation of the radio link.
[0060] It should be noted that the display unit can take on many
alternative forms in aspects of the guiding means 130, such as a
simple arrangement of diodes, or audio means which indicate a
preferred direction by playing a sound to the user.
[0061] Consequently, the guiding means 130 comprises a display unit
132 adapted to display at least one out of: a first indicator 333
indicating the present direction of the first directive antenna, a
second indicator 334 indicating the location of the second antenna,
and a third indicator 335 indicating the preferred direction of the
first directive antenna 110, thus facilitating alignment of the
first directive antenna 110.
[0062] According to an aspect, the display unit 132 is further
adapted to display an image showing a camera view as seen from the
first directive antenna 110, in the current direction of the first
directive antenna 110.
[0063] Of course, the display unit can take on many forms in
different aspects of the alignment tool. One example as noted above
being a visual display unit which displays an image captured by a
camera, in which image the location of the far end antenna and the
preferred direction have been marked by visual indicators, another
example being a display unit which shows one or several direction
indicators, possibly in the shape of arrows, which point in the
direction of the far end antenna and in the preferred direction. An
even simpler display unit would just comprise one or several light
emitting diodes, LEDs, which guides the user to direct the first
directive antenna in a preferred direction, the preferred direction
suitably being indicated by a pre-determined LED.
[0064] FIG. 4 shows a non-line-of-sight, NLOS, communication
channel with first 110 and second 410 antennas. The channel between
the first 110 and second 410 antenna is blocked by obstacles 420,
421. However, radio signals transmitted from, e.g., the second
antenna 410 can still reach the first antenna 110 by means of
reflection 422 or diffraction 423. It is also noted that in this
aspect there are at least two preferred directions of the first
directive radio antenna 110. The tool for radio antenna alignment
is in this aspect constructed such as to provide a user with a
plurality of alternative preferred directions. The user of the tool
can then select between the preferred directions when mounting the
antenna. In case of a plurality of preferred directions, the
guiding means is suitably adapted to display each of these
preferred directions to a user of the tool, possibly by means of
additional indicators on the display unit 132 of the guiding means
130.
[0065] Thus, the radio antenna alignment tool 400 is adapted to
determine a plurality of preferred directions of the first
directive antenna 110 with respect to the second antenna 410, which
preferred directions are suitable for communication over an NLOS
communication channel where an obstacle 420, 421 blocks the
line-of-sight, LOS, between the first directive antenna 110 and the
second antenna 410, by evaluating a plurality of alternative
propagation paths, including propagation paths with reflection 422
and propagation paths with diffraction 423.
[0066] The user is in the present aspect given a plurality of
different alternatives in which to direct the first directive
antenna 110. This could be beneficial in cases where some
directions are difficult to achieve for practical reasons, e.g.,
due to the mounting of the first directive antenna 110. For
instance, the mounting of the antenna could be such as to not allow
certain antenna angles.
[0067] According to an aspect, the radio antenna alignment tool 400
also comprises an emitter unit 430 disposed in connection to the
second antenna 410, the emitter unit 430 is arranged to transmit a
known signal. The sensor unit 120 is in this case adapted to
receive the known signal, as well as to measure the power of the
received known signal. The guiding means 130 is further arranged to
receive said power measurement value from the sensor unit 120, and
to indicate said power measurement value to a user of the tool, as
well as to determine the preferred direction of the first directive
antenna 110 based on said power measurement value.
[0068] The emitter unit 430 suitably uses an isotropic antenna or
an antenna with a less narrow main lobe compared to the first
directive antenna 110, such that a signal can be received from the
emitter despite poor alignment of the emitter antenna with respect
to the first directive antenna 110.
[0069] According to an aspect, the emitter unit 430 and sensor unit
120 further comprises first and second antenna arrays,
respectively. The emitter unit 430 is in this aspect arranged to
transmit a known narrow-beam signal in a pre-determined sequence
over a first pre-determined range of antenna array beam transmit
directions. The sensor unit 120 is arranged to measure received
signal power over a second pre-determined range of antenna array
beam receive directions, as well as to communicate said power
measurements and corresponding receive beam directions to the
guiding means 130. The guiding means 130 is arranged to store said
power measurements together with the corresponding receive beam
directions in a memory, and to select a suitable direction of the
first directive antenna 110 based on said received power
measurements and corresponding receive beam directions.
[0070] Thus a range of transmit and receive direction combinations
can be scanned automatically, and a user can quickly evaluate a
range of possible alignment options and select a promising
direction of both the near end antenna and the far end antenna.
This is suitable in cases of complicated propagation conditions
where it is difficult to calculate or otherwise determine a
preferred direction by means of, e.g., image processing or ray
tracing techniques.
[0071] FIG. 5 shows a flowchart of a method for aligning a first
directive antenna and at least a second antenna in
non-line-of-sight, NLOS, communication conditions. The method
comprising the steps of; [0072] Sensing 510 a current direction of
the first directive antenna, [0073] Determining 520 a preferred
direction of the first directive antenna, which preferred direction
maximizes a signal quality metric for communication between the
first and second antenna, [0074] Presenting 530 to a user at least
one out of: the current direction of the first directive antenna,
the location of the second directive antenna, the preferred
direction of the first directive antenna.
[0075] According to an aspect, the step of sensing 510 further
comprises sensing at least one out of a camera image as seen from
the first directive antenna, the coordinates of the first directive
antenna, and the coordinates of the second directive antenna.
[0076] According to an aspect, an emitter is disposed in connection
to the second directive antenna and arranged to transmit a known
radio signal, and the step of sensing 510 further comprises
measuring a received signal power by means of a radio receiver unit
connected to the first directive radio antenna and adapted to
receive the known radio signal.
[0077] According to an aspect, the step of determining 520 further
comprises determining the preferred direction to maximize the
signal quality metric based on at least one out of: the result from
the step of sensing, a measurement of received signal power, and
map information, which map information comprises pre-determined
building coordinates, antenna unit coordinates, and building
geometry.
[0078] The above stated object of the disclosure is further
obtained by a computer program for assisting in aligning a first
directive antenna 110 with respect to at least a second antenna.
The computer program, when executed by a processor of a mobile
device, causes the mobile device to perform any one of the methods
disclosed herein.
[0079] The above stated object of the disclosure is also obtained
by a mobile device for assisting in aligning a first directive
antenna 110 with respect to at least a second antenna, comprising a
processor, and a storage medium for storing computer programs
executable by said processor.
[0080] The foregoing has described the principles, preferred
aspects and modes of operation of the present disclosure. However,
the invention described herein should be regarded as illustrative
rather than restrictive, and not as being limited to the particular
aspects discussed above. The different features of the various
aspects of the disclosure can be combined in other combinations
than those explicitly described. It should therefore be appreciated
that variations may be made in those aspects by those skilled in
the art without departing from the scope of the present disclosure
as defined by the following claims.
* * * * *