U.S. patent application number 12/021895 was filed with the patent office on 2008-08-07 for cellular antenna.
Invention is credited to Peter Bruce Graham, Andrew Thomas Gray, Daniel Rhodes, Arthur George Roberts.
Application Number | 20080186107 12/021895 |
Document ID | / |
Family ID | 26652194 |
Filed Date | 2008-08-07 |
United States Patent
Application |
20080186107 |
Kind Code |
A1 |
Rhodes; Daniel ; et
al. |
August 7, 2008 |
Cellular Antenna
Abstract
An antenna for communicating with mobile devices in a land-based
cellular communication system via an antenna beam having a width,
azimuth angle and downtilt angle. The antenna includes: a two
dimensional array of radiating elements (31-34); and a feed network
(35-39) from a feed line to the radiating elements. The feed
network includes: downtilt phase shifting means (35,36) for varying
the phase of signals supplied to or received from the radiating
elements so as to vary the downtilt angle of the antenna beam;
azimuth phase shifting (38,39) means for varying the phase of
signals supplied to or received from the radiating elements so as
to vary the azimuth angle of the antenna beam; and beam width
adjustment means (37) for varying the power or phase of signals
supplied to or received from the radiating elements so as to vary
the width of the antenna beam.
Inventors: |
Rhodes; Daniel; (Wellington,
NZ) ; Gray; Andrew Thomas; (Wellington, NZ) ;
Roberts; Arthur George; (Wellington, NZ) ; Graham;
Peter Bruce; (Wellington, NZ) |
Correspondence
Address: |
WELSH & KATZ, LTD
120 S RIVERSIDE PLAZA, 22ND FLOOR
CHICAGO
IL
60606
US
|
Family ID: |
26652194 |
Appl. No.: |
12/021895 |
Filed: |
January 29, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10312979 |
Jun 16, 2003 |
|
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PCT/NZ01/00137 |
Jul 10, 2001 |
|
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12021895 |
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Current U.S.
Class: |
333/136 ;
333/156 |
Current CPC
Class: |
H01Q 21/22 20130101;
H01P 1/18 20130101; H01Q 3/36 20130101; H01Q 21/061 20130101; H01Q
1/246 20130101; H01Q 3/26 20130101; H01Q 3/24 20130101; H01Q 3/32
20130101; H01P 5/04 20130101 |
Class at
Publication: |
333/136 ;
333/156 |
International
Class: |
H01P 1/18 20060101
H01P001/18; H01P 5/12 20060101 H01P005/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 10, 2000 |
NZ |
505656 |
Apr 3, 2001 |
NZ |
510913 |
Claims
1. An antenna for communicating with mobile devices in a land-based
cellular communication system via an antenna beam having a width,
azimuth angle and downtilt angle, the antenna including: a two
dimensional array of radiating elements; and a feed network from a
feed line to the radiating elements, the feed network including:
downtilt phase shifting means for vary the phase of signals
supplied to or received form the radiating elements so as to vary
the downtilt angle of the antenna beam; azimuth phase shifting
means for varying the phase of signals supplied to or received from
the radiating elements so as to vary the azimuth angle of the
antenna beam; and beam width adjustment means for varying the power
or phase of signals supplied to or received form the radiating
elements so as to vary the width of the antenna beam
2. The antenna of claim 1 wherein the beam width adjustment means
includes power dividing means for varying the division of power
between radiating elements so as to vary the width of the antenna
beam.
3. The antenna of claim 2 wherein the power dividing means divides
power between one or more central radiating elements and two or
more outer radiating elements positioned in the array on opposite
sides of the central radiating elements(s).
4. The antenna of claim 2 or 3 wherein the power dividing means is
substantially non-attenuating.
5. The antenna of claim 3 or 4 wherein the downtilt phase shifting
means adjusts the relative phase between the pair of outer
radiating elements.
6. The antenna of claim 3, 4 or 5 wherein the phase relationship
between the central radiating elements(s) and the power dividing
means is substantially fixed for all values of downtilt and azimuth
angle.
7. The antenna of claim 3, 4, 5 or 6 wherein the azimuth phase
shifting means adjusts the relative phase between the pair of outer
radiating elements.
8. The antenna of claim 1 wherein the beam width adjustment means
includes means for varying the phase of signals supplied to or
received from the radiating elements so as to vary the width of the
antenna beam.
9. The antenna of any of the preceding claims wherein the array
includes at least three rows and at least three columns of
radiating elements.
10. The antenna of any of the preceding claims wherein the beam
width is adjustable in an azimuthal direction.
11. An antenna for communicating with mobile devices in a
land-based cellular communication system via an antenna beam having
a width and an angle, the antenna including: a plurality of
radiating elements; and a feed network from a feed line to the
radiating elements, the feed network including: power dividing
means for varying the division of power between radiating elements
so as to vary the width of the antenna beam; and phase shifting
means for varying the phase of signals supplied to or received from
the radiating elements so as to vary the angle of the antenna
beam.
12. The antenna of claim 11 wherein the power dividing means
divides power between one or more central radiating elements and
two or more outer radiating elements positioned on opposite sides
of the central radiating elements(s).
13. The antenna of claim 11 or 12 wherein the power dividing means
is substantially non-attenuating.
14. The antenna of claim 12 wherein the phase shifting means
adjusts the relative phase between the pair of outer radiating
elements.
15. The antenna of claim 14 wherein the phase relationship between
the central radiating elements(s) and the power dividing means is
substantially fixed for all values of beam angle.
16. The antenna of any one of claims 12 to 15 wherein the angle is
an azimuth angle
17. The antenna of any one of claims 12 to 16 wherein the angle is
a downtilt angle.
18. The antenna of claim 16 and 17 wherein the phase shifting means
can vary the azimuth and downtilt angle of the antenna beam.
19 the antenna of any of the preceding claims wherein the or each
phase shifting means is adjusted by varying the relative position
of two or more phase shifting components.
20. A land-based antenna system including one or more antennas
according to any of the preceding claims; and an encoder for
encoding downlink signals for transmission to the radiating
elements according to a code-division multiplexing (CDMA)
scheme.
21. A land-based antenna system including one or more antennas
according to any of the preceding claims; and a decoder for
decoding uplink signals received from the radiating elements
according to a code-division multiplexing (CDMA) scheme.
22. The land-based antenna system of claim 20 or 21 including
control means adapted to provide signals to the antenna(s) to
adjust a characteristic of the antenna beam.
23. A land-based antenna system including one or more antennas
according to any of claims 1 to 19; and control means adapted to
provide signals to the antenna(s) to adjust a characteristic of the
antenna beam.
24. The system of claim 23 wherein the control means comprises a
local receiver adapted to receive commands from a remote control
centre.
25. The system of claim 23 or 24 including a plurality of antennas,
and wherein the control means includes: means for receiving a
command to change a beam characteristic of one of the antennas;
means for calculating the beam characteristic required for all of
the antennas to achieve a desired coverage; and means for adjusting
one or more beam characteristic of each antenna as required to
achieve the desired coverage.
26. The system of claim 22, 23, 24, 25 or 26 wherein the control
means includes: graphical user interface means for graphically
displaying parameters of the configuration of a plurality of
antennas wherein, via use of an input device, graphical elements
may be manipulated to adjust parameters of the configuration; and
communication means for sending control signals to an actuation
means to adjust parameters of an antenna in accordance with those
displayed by the graphical user interface.
27. An antenna system for communicating with mobile devices in a
land-based cellular communication system via an antenna beam, the
antenna system including: an antenna having a plurality of
radiating elements, and an RF feed line for transmitting signals to
and/or from the radiating elements; transmission means coupled to
the RF feed line; and control means for adjusting a characteristic
of the antenna beam in accordance with control data received from
the transmission means via the RF feed line.
28. An antenna system for communicating with mobile devices in a
land-based cellular communication system, the antenna system
including: a plurality of antennas each having phase shifting means
for adjusting a characteristics of the beam of the antenna, each
antenna being provided at an elevated height on a structure; and an
antenna control system for controlling the phase shifting means,
the antenna control system being provided at an elevated height
near the antennas.
29. An antenna system for communicating with mobile devices in a
land-based cellular communication system, the antenna system
including: a plurality of radiating elements; one or more phase
shifter provided in a feed network to the plurality of radiating
elements for adjusting a characteristic of the beam of the antenna;
and control means for driving electromechanical means associated
with each phase shifter wherein the control means includes
processing means to control the antenna in accordance with control
data supplied thereto.
30. The system of any of claims 25 to 29 wherein the antenna is an
antenna according to any of claim 1 to 19.
31. A land-based cellular communication system including one or
more systems according to any of claims 20 to 30; and a remote
control centre for issuing commands to each system to adjust
antenna beam characteristics of each system.
32. An antenna control system for controlling the beam
characteristics of a plurality of antennas which communicate with
mobile devices in a land-based cellular communication system, the
antenna control system including: means for receiving a command to
change a beam characteristic of one of the antennas; means for
calculating the beam characteristics required for all of the
antennas to achieve a desired coverage; and means for adjusting one
or more beam characteristic of each antenna as required to achieve
the desired coverage.
33. A computer for controlling an antenna which communicates with
mobile devices in a land-based cellular communication system, the
computer including: graphical user interface means for graphically
displaying parameters of the configuration of a plurality of
antennas wherein, via use of an input device, graphical elements
may be manipulated to adjust parameters of the configuration; and
communication means for sending control signal to an actuation
means to adjust parameters of an antenna in accordance with those
displayed by the graphical user interface.
34. The hand held device including the computer of claim 33.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an antenna for
communicating with mobile devices in a land-based cellular
communication system. The invention also relates to an antenna
system and a cellular communication system incorporating one or
more antennas.
BACKGROUND OF THE INVENTION
[0002] Antennas used in early cellular base stations typically did
not include means for varying antenna beam direction and had to be
mounted to a support structure at an inclination required to
provide a beam producing the required cell coverage. More recent
antennas have included means for remotely adjusting downtilt of the
beam of an antenna of a cellular base station. WO96/14670 discloses
an antenna having mechanically adjustable phase shifters which
produce variable electrical phase shifts in the feed path of the
antenna to effect downtilting of the beam of an antenna.
[0003] Phased array antennas, used in radar applications, provide
both azimuth beam steering and vertical beam tilting (downtilt) to
direct the beam of an antenna in a required direction. Such
antennas have typically employed active switching elements and been
of complex and expensive construction.
[0004] If more than one characteristic of the beam of an antenna of
a cellular base station could be varied, cellular communication
systems could be more flexible in allocating capacity to desired
areas.
[0005] The applicant's prior application WO96/14670 discloses an
antenna control system for remotely adjusting the downtilt of a
plurality of antennas. The controller 80 is located at the base of
a cellular base station and a separate cable 78 is required to
control each antenna. This requires a new control cable 78 to be
run from the mast head to controller 80 each time a new antenna is
added.
[0006] In the system of WO96/14670 each antenna is identified by
the port to which cable 78 is connected. The number of antennas
that may be controlled by a controller 80 is limited by the number
of available ports.
[0007] Prior art systems have utilised proprietary controllers to
remotely adjust antenna characteristics. It would be desirable to
enable standard devices that are widely available to be utilised to
program and control the antenna control systems.
DISCLOSURE OF THE INVENTION
[0008] It is an object of the invention to provide an antenna
control system, an antenna and an antenna system that overcomes at
least some of the limitations of the prior art or to at least
provide the public with a useful choice.
[0009] A first aspect of the invention provides an antenna for
communicating with mobile devices in a land-based cellular
communication system via an antenna beam having a width, azimuth
angle and downtilt angle, the antenna including: [0010] a two
dimensional array of radiating elements; and [0011] a feed network
from a feed line to the radiating elements, the feed network
including: [0012] downtilt phase shifting means for varying the
phase of signals supplied to or received from the radiating
elements so as to vary the downtilt angle of the antenna beam;
[0013] azimuth phase shifting means for varying the phase of
signals supplied to or received from the radiating elements so as
to vary the azimuth angle of the antenna beam; and [0014] beam
width adjustment means for varying the power or phase of signals
supplied to or received from the radiating elements so as to vary
the width of the antenna beam
[0015] The first aspect of the invention provides an antenna having
a beam angle which is adjustable in horizontal (azimuth) and
vertical (downtilt) directions, as well as having adjustable beam
width.
[0016] A second aspect of the invention provides an antenna for
communicating with mobile devices in a land-based cellular
communication system via an antenna beam having a width and an
angle, the antenna including: [0017] a plurality of radiating
elements; and [0018] a feed network from a feed line to the
radiating elements, the feed network including: [0019] power
dividing means for varying the division of power between radiating
elements so as to vary the width of the antenna beam; and [0020]
phase shifting means for varying the phase of signals supplied to
or received from the radiating elements so as to vary the angle of
the antenna beam.
[0021] The second aspect provides a preferred feed network which
gives adjustable beam width and adjustable beam angle (which may be
adjustable in the azimuth and/or downtilt directions).
[0022] Preferably the power dividing means divides power between
one or more central radiating elements and two or more outer
radiating elements positioned in the array on opposite sides of the
central radiating element(s).
[0023] Preferably the power dividing means is a substantially
non-attenuating power divider, for example including a pair of
hybrid couplers and a phase shifter between the hybrid
couplers.
[0024] Preferably the downtilt or azimuth phase shifting means
adjusts the relative phase between the pair of outer radiating
elements.
[0025] Preferably the phase relationship between the central
radiating element(s) and the power dividing means is substantially
fixed for all beam angles.
[0026] In an alternative arrangement the beam width adjustment
means includes means for varying the phase of signals supplied to
or received from the radiating elements so as to vary the width of
the antenna beam.
[0027] Preferably the array includes at least three rows and at
least three columns of radiating elements.
[0028] The antenna is particular suited to a code-division multiple
access system (CDMA or W-CDMA) employing a CDMA encoder and/or
decoder.
[0029] Typically the antenna is part of a land-based antenna system
including control means adapted to provide signals to the
antenna(s) to adjust a characteristic of the antenna beam.
[0030] The control means typically includes a local receiver
adapted to receive commands from a remote control centre.
[0031] A third aspect of the invention provides an antenna system
for communicating with mobile devices in a land-based cellular
communication system via an antenna beam, the antenna system
including: [0032] an antenna having a plurality of radiating
elements, and an RF feed line for transmitting signals to and/or
from the radiating elements; [0033] transmission means coupled to
the RF feed line; and [0034] control means for adjusting a
characteristic of the antenna beam in accordance with control data
received from the transmission means via the RF feed line.
[0035] A fourth aspect of the invention provides an antenna system
for communicating with mobile devices in a land-based cellular
communication system, the antenna system including: [0036] a
plurality of antennas each having phase shifting means for
adjusting a characteristic of the beam of the antenna, each antenna
being provided at an elevated height on a structure; and [0037] an
antenna control system for controlling the phase shifting means,
the antenna control system being provided at an elevated height
near the antennas.
[0038] A fifth aspect of the invention provides an antenna system
for communicating with mobile devices in a land-based cellular
communication system, the antenna system including: [0039] a
plurality of radiating elements; [0040] one or more phase shifter
provided in a feed network to the plurality of radiating elements
for adjusting a characteristic of the beam of the antenna; and
[0041] control means for driving electromechanical means associated
with each phase shifter wherein the control means includes
processing means to control the antenna in accordance with control
data supplied thereto.
[0042] The systems according to the invention are typically
provided as part of a land-based cellular communication system
including a remote control centre for issuing commands to each
antenna system to adjust antenna beam characteristics of each
system.
[0043] A sixth aspect of the invention provides an antenna control
system for controlling the beam characteristics of a plurality of
antennas which communicate with mobile devices in a land-based
cellular communication system, the antenna control system
including: [0044] means for receiving a command to change a beam
characteristic of one of the antennas; [0045] means for calculating
the beam characteristics required for all of the antennas to
achieve a desired coverage; and [0046] means for adjusting one or
more beam characteristic of each antenna as required to achieve the
desired coverage.
[0047] A seventh aspect of the invention provides a computer for
controlling an antenna which communicates with mobile devices in a
land-based cellular communication system, the computer including:
[0048] graphical user interface means for graphically displaying
parameters of the configuration of a plurality of antennas wherein,
via use of an input device, graphical elements may be manipulated
to adjust parameters of the configuration; and [0049] communication
means for sending control signals to an actuation means to adjust
parameters of an antenna in accordance with those displayed by the
graphical user interface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] The invention will now be described by way of example with
reference to the accompanying drawings in which:
[0051] FIG. 1: shows a three radiating element array antenna;
[0052] FIG. 2: shows a schematic diagram of the feed network for
the antenna shown in FIG. 1;
[0053] FIG. 2A: shows the variable power divider;
[0054] FIG. 3: shows a six element array antenna;
[0055] FIG. 4: shows a schematic diagram of the feed network of the
antenna shown in FIG. 3;
[0056] FIG. 5: shows a four element array antenna;
[0057] FIG. 6: shows a schematic diagram of the feed network of the
antenna shown in FIG. 5;
[0058] FIG. 7: shows a ten element array antenna;
[0059] FIG. 8 shows a schematic diagram of the feed network of the
antenna shown in FIG. 7.
[0060] FIG. 9: shows the control arrangement of the antenna shown
in FIGS. 7 and 8.
[0061] FIG. 10: shows a cellular communications system.
[0062] FIGS. 11 to 14: disclose an embodiment utilising only phase
shifters.
[0063] FIGS. 15 & 16: show an embodiment utilising only phase
shifters for adjustment of antenna beam direction and width in two
dimensions.
[0064] FIG. 17: shows a minimal implementation for effecting beam
steering and beam width adjustment.
[0065] FIG. 18: shows an antenna system according to a first
embodiment.
[0066] FIG. 19: shows a first control system implementation for the
embodiment of FIG. 18.
[0067] FIG. 20: shows a second control system implementation for
the embodiment of FIG. 18.
[0068] FIG. 21: shows a third control system implementation for the
embodiment of FIG. 18.
[0069] FIG. 22: shows an antenna system according to a second
embodiment.
[0070] FIG. 23: shows a first control system implementation for the
embodiment of FIG. 22.
[0071] FIG. 24: shows a second control system implementation for
the embodiment of FIG. 22.
[0072] FIG. 25: shows an antenna system according to a third
embodiment.
[0073] FIG. 26: shows the control system of the embodiment shown in
FIG. 25.
[0074] FIG. 27: shows an antenna system according to a fourth
embodiment.
[0075] FIG. 28: shows a control system implementation for the
embodiment of FIG. 27.
[0076] FIG. 29: shows a remote control system according to a first
embodiment.
[0077] FIG. 30: shows a remote control system according to a second
embodiment.
[0078] FIG. 31: shows a graphical user interface according to one
embodiment.
[0079] FIG. 32: shows a user interface for adjusting downtilt.
[0080] FIG. 33: shows a tabular interface.
[0081] FIG. 34: shows a scheduling interface.
DETAILED DESCRIPTION OF BEST MODE FOR CARRYING OUT THE
INVENTION
[0082] Referring to FIG. 1 an antenna 1 has an array of three
radiating elements 2, 3, 4 arranged in a single row. FIG. 2 shows a
schematic diagram of the feed network 5 from a connector 6 to the
radiating elements 2, 3 and 4. Power divider 7 divides power
between antennas 2 and 4 and antenna 3. Adjustment of power divider
7 results in variation of beam width of the beam of antenna 1.
[0083] Power divider 7 is shown in detail in FIG. 2A. A first
hybrid coupler 71 has an input port 72 coupled to connector 6 and a
port 73 which is isolated. The hybrid coupler 71 splits the input
signal into two signals with equal amplitude which are output on
lines 74, 75 with a phase difference of 90. The phase of the signal
on line 75 can be adjusted by a phase shifter 79 which adjust the
length L2 of line 75 compared to the length L1 of line 74. The
lines 74, 75 are coupled to a second hybrid coupler 76 which splits
and combines the signals with a 90 phase shift. When L1=L2 the
signals interfere constructively at output 78 and cancel each other
out at output 77. If L1 L2 then the signal is divided between
outputs 77, 78, the ratio being determined by the position of the
phase shifter 79. For a certain ratio between L1 and L2 all of the
signal is output on output 77 and no signal is output on output 78.
It will be noted that the power divider 7 is substantially
non-attenuating--that is, it does not employ any attenuators (such
as resistors) which would result in power loss and overheating.
[0084] Phase shifters 8 and 9 differentially vary the phase of
radiating elements 2 and 4 with respect to radiating element 3.
Phase shifters 8 and 9 may be incorporated within a single variable
differential phase shifter of the type described in WO 96/14670.
Adjustment of phase shifters 8 and 9 results in azimuth steering of
the antenna beam.
[0085] The simple three element array described in FIGS. 1 and 2
thus allows azimuth steering by adjustment of phase shifters 8 and
9 and azimuthal beam width adjustment by variation of power divider
7.
[0086] Referring now to FIG. 3, antenna 10 includes six radiating
elements 11 to 16. In FIG. 4 a schematic diagram of the feed
network for the antenna shown in FIG. 3 is shown.
[0087] Signals are conveyed to or from connector 17 to or from the
radiating elements via the feed network 18. Phase shifter 19 varies
the phase of signals received from or sent to radiating elements
11, 12 and 13 with respect to those received from or transmitted to
radiating elements 14, 15 and 16. Variation of the phase between
the rows of radiating elements 11 to 13 compared to those of rows
14 to 16 results in vertical tilting of the beam of the antenna
(downtilting). Adjustment of phase shifter 19 may thus be utilised
to effect downtilting of the beam of the antenna.
[0088] The power dividers 20 and 23 and the phase shifters 21, 22,
24 and 25 operate in the manner described in relation to FIG. 2.
Power dividers 20 and 23 may be adjusted to modify beam width of
the beam of the antenna and phase shifters 21 and 22 and phase
shifters 24 and 25 may be adjusted to modify azimuth of the beam of
the antenna. Power dividers 20 and 23 may be driven by a common
mechanical linkage so that the beam width is adjusted uniformly for
both rows of radiating elements. Likewise, phase shifters 21 and 22
and phase shifters 24 and 25 may be driven by a common mechanical
linkage so that the azimuth of the beam of the antenna is constant
for both rows.
[0089] Referring now to FIG. 5 an alternative diamond arrangement
of elements is shown. Antenna 30 includes radiating elements 31,
32, 33 and 34. FIG. 6 shows the feed network for the antenna
arrangement shown in FIG. 5.
[0090] Phase shifters 35 and 36 differentially vary the phase of
the signals supplied to radiating elements 31 and 34 compared with
the phase of signals supplied to radiating elements 32 and 33.
Adjustment of phase shifters 35 and 36 may thus adjust downtilt of
the beam of the antenna. Phase shifters 35 and 36 may be provided
as a single variable differential phase shifter.
[0091] Power divider 37 adjusts the division of power between
radiating elements 32 and 33 and radiating elements 31 and 34. This
enables adjustment of beam width of the beam of the antenna.
[0092] Phase shifters 38 and 39 allow variable differential phase
shifting of the phase of signals supplied to or received from
radiating elements 32 and 33 with respect to the phase of signals
supplied to or received from radiating elements 31 and 34. This
enables adjustment of the azimuth of the beam of the antenna. Phase
shifters 38 and 39 may be provided as a single variable
differential phase shifter.
[0093] Referring now to FIG. 7 an antenna configuration of a
preferred design for use in cellular communications base stations
is shown. An antenna for use in a cellular base station preferably
includes at least 3 columns of elements and 3 vertically spaced
apart groups of elements. This enables good beam symmetry to be
achieved. Antenna 40 includes radiating elements 41 to 50 arranged
in three columns: 42, 45 and 48; 41, 44, 47 and 50; and 43, 46 and
49. The radiating elements are also divided into three groups
41-43; 44-47; and 48-50. These three groups fall within three broad
rows across antenna 40.
[0094] Referring now to FIG. 8 the feed network 51 is shown
schematically. Phase shifters 52 and 53 differentially shift the
phase of signals received from/sent to the first row of radiating
elements (41-43) and the third row of radiating elements (48-50)
with respect to the middle row of radiating elements (44-47). This
allows the downtilt of the beam of the antenna to be adjusted by
variation of phase shifters 52 and 53. Phase shifters 52 and 53 may
be a single variable differential phase shifter.
[0095] Power dividers 54 to 56 may be adjusted to vary beam width
in the same manner previously described. Power dividers 54 to 56
are preferably constructed and arranged so that they are adjusted
simultaneously so that the beam width of the antenna is constant
for each group of radiating elements.
[0096] Phase shifters 57 to 62 operate in the same manner as
discussed previously to effect azimuth steering. Each pair of phase
shifters 57 and 58; 59 and 60; and 61 and 62 may consist of a
single variable differential phase shifter. Again these phase
shifters are preferably driven in tandem so that the azimuth of the
beam of each group of radiating elements is aligned.
[0097] Another preferred arrangement is an array of 15 radiating
elements regularly arranged in 5 rows and 3 columns.
[0098] It will be appreciated that a range of other possible
radiating element and feed arrangements may be employed depending
upon the requirements for a particular application.
[0099] The radiating elements shown in these embodiments are dipole
pairs suitable for use in a dual polarisation antenna. Other
radiating elements may be substituted if appropriate for other
applications.
[0100] Referring now to FIG. 9 control means for controlling the
phase shifters of the antenna shown in FIGS. 7 and 8 is shown. A
control means 63 drives motive means 64 to 66. Motive means 64 to
66 may be suitably geared electrical motors or the like.
[0101] Motive means 64 adjusts a variable differential phase
shifter 70 (phase shifters 52 and 53) to vary the downtilt of the
beam of the antenna. Motive means 65 adjusts phase shifters 80, 81
and 82 (phase shifters 57-62) via linkages 69 to adjust the azimuth
of the beam of the antenna. Motive means 66 adjusts power dividers
54 to 56 via linkages 68 to adjust beam width of the beam of the
antenna. The drive mechanisms and linkages may be of the type
disclosed in WO 96/14670.
[0102] Port 83 enables control means 63 to communicate with a
remote control means. Typically port 83 will be connected to a
modem to facilitate remote communication with a control centre via
a physical or wireless communication. Control means 63 may convey
information about the current configuration and status of the
antenna to the remote control centre and the remote control centre
may provide instructions for adjustment of the downtilt, azimuth or
beam width of the antenna which may be implemented by control means
63. Control means 63 preferably controls a plurality of antennas of
the same type as antenna 40.
[0103] Referring now to FIG. 10 there is shown a cellular
communications system in which a control centre 84 is connected to
control means 63, 85 and 86 via data links 89 to 91 (physical or
wireless). Antennas 87, 88 and 92-97 are of the same type as
antenna 40 described above. The phase shifters of the antennas 40,
87 and 88 may be controlled by control means 63 in accordance with
instructions received from the control centre 84 over the data link
89. Likewise antennas 92 to 94 at another cellular base station are
controlled by control means 85 and antennas 95 to 97 are controlled
by control means 86.
[0104] It will be appreciated that any number of controllers 63, 85
and 86 may be controlled by a central control centre 84. This
enables the zones covered by antennas 40, 87 and 88, antennas 92-94
and antennas 95 to 97 to be controlled by control centre 84
dynamically to meet any demands placed upon a communications system
or to configure the system to any desired pattern of coverage.
[0105] In an alternative arrangement, the fixed control centre 84
may be replaced (or supplemented) with a mobile (roving) network
optimisation unit which communicates via a wireless link.
[0106] Referring now to FIGS. 11 to 13 an alternative arrangement
is shown in which azimuth steering and beam width adjustment is
achieved by the use of phase shifters alone.
[0107] In this embodiment phase shifters 103 and 104 are
independently adjustable. However, phase shifters 103 and 104 could
be driven by suitable linkages that enable phase shifters 103 and
104 to be adjusted differentially and in a non-differential manner
to achieve azimuth steering and beam width adjustment in a desired
manner.
[0108] Radiating element 100 is connected directly to feed point
105, radiating element 101 is connected via phase shifter 103 to
feed point 105 and radiating element 102 is connected via phase
shifter 104 to feed point 105. Phase shifters 103 and 104 may be
independently driven by suitable motive means such as a suitably
geared electric motor which is responsive to control signals from a
control means such as control means 63 shown in FIGS. 9 and 10.
[0109] In FIG. 11 phase shifters 103 and 104 are seen to be
adjusted in a differential manner to effect beam steering. In FIGS.
12 and 13 phase shifters 103 and 104 phase shifters 103 and 104 are
adjusted in unison to effect widening or narrowing of the beam of
the antenna. It will be appreciated that when the phase shift to
antennas 101 and 102 is increased the beam of the antenna will be
widened and when the phase shift is reduced that the beam of the
antenna will be narrowed. It will be appreciated that independent
adjustment of phase shifters 103 and 104 enables steering and beam
width adjustment to be performed simultaneously using only two
phase shifters.
[0110] FIG. 14 shows the physical arrangement of radiating elements
100 to 102 of a panel antenna 106.
[0111] Referring now to FIGS. 15 and 16 an embodiment of the
concept described in FIGS. 11 to 14 is shown using a two
dimensional array of radiating elements. In this case radiating
elements 107 to 110 of panel antenna 111 are arranged in a diamond
configuration.
[0112] As shown in FIG. 16 each radiating element 107 to 110 is
connected to feed point 116 via a phase shifter 112 to 115. Each of
the phase shifters 112 to 115 is independently adjustable.
Differential adjustment of phase shifters 114 and 115 can produce
azimuth beam steering. Non differential adjustment of phase
shifters 114 and 115 can alter the beam width in the horizontal
plane. Differential adjustment of phase shifters 112 and 113 can
result in beam tilting in the vertical plane. Non differential
adjustment of phase shifters 112 and 113 can result in beam width
adjustment in the vertical plane.
[0113] This arrangement thus enables beam steering in the vertical
and horizontal planes as well as beam width adjustment in the
vertical and horizontal planes.
[0114] FIGS. 15 to 16 show a minimal implementation of the concept
and it will be appreciated that greater numbers of radiating
elements may be desirable depending upon the application concerned.
Although the phase shifters 112 to 115 have been described as being
independently adjustable it will be appreciated that the phase
shifters may be suitably driven via common mechanical linkages to
achieve desired beam shape and direction adjustments.
[0115] Referring now to FIG. 17 a minimal implementation for
effecting beam width adjustment and azimuth steering is disclosed
for completeness. Power divider 119 divides power between radiating
elements 117 and 118 to effect beam width adjustment. Phase shifter
121 may be adjusted to effect azimuth steering. This embodiment is
described for the sake of completeness and would not be a preferred
design due to the lack of symmetry of the beam when radiating
elements 117 and 118 are not driven equally.
[0116] In a system of the type shown in FIG. 10 it will be
appreciated that control centre 84 may need to simultaneously
adjust the beam width and/or beam direction of a number of antennas
simultaneously. Adjustment of the cell coverage of one antenna may
leave a gap that needs to be filled by another antenna. Control
centre 84 will preferably have suitable computing means and
software to calculate required antenna adjustments to achieve a
desired coverage.
[0117] Referring to FIG. 18 there is an antenna system 201
consisting of a structure 202 supporting a plurality of antennas
203 to 205. Each of the antennas 203-205 may be any one of the
antennas shown in FIGS. 1-17. A transmission unit provides control
signals to antennas 203 to 205 by injecting control data onto RF
feed cables to the antennas. Transmission means 206 has an
interface port connected via serial cable 207 to socket 208. A PDA,
such as a Palm Pilot.TM., is connected to an interface unit 210
which is connected to socket 208 via cable 211. Interface unit 210
connects to a port of PDA 209 and converts from an RS 232 serial
communication protocol to an RS 485 serial protocol. Alternatively
PDA 209 may connect to transmission means 206 by a direct RS 232
connection.
[0118] FIGS. 19 to 21 show three possible control system
implementations for the antenna system of FIG. 18. Like components
have been given like numbers throughout.
[0119] Referring firstly to FIG. 19 a first control system
implementation is shown. In this case transmission means 206
injects control data onto each RF feed line 212, 213, 214 to each
antenna 203, 204 and 205. Each antenna includes an individual
actuation means 215, 216, and 217 which extracts control data from
the respective RF cable 212, 213 and 214 and drives actuators 218,
219 and 220 in accordance with the control data. Typically
actuators 218 to 220 will be electromechanical means for relatively
moving parts of one or more phase shifter of each antenna to adjust
downtilt and/or azimuth and/or beam width. The use of
electromechanical phase shifters ensures operating parameters
remain unchanged in case of a power failure. Actuation means 215 to
217 may also include transceivers for antennas 203 to 205.
[0120] Each antenna 203, 204 and 205 is also provided with unique
identification means 221, 222 and 223 this may be a chip which
stores a unique number, a series of switches or resistors etc. This
enables the actuation means 215, 216 and 217 to uniquely identify
each antenna and provide information in association with the
antenna ID. Although not shown in subsequent drawings this feature
may be incorporated in each other embodiment described below.
[0121] The transmission means 206 may be provided at any convenient
location, for example within a base station. The arrangement has
the advantage that no specific control cabling is required to
control each antenna 203, 204 and 205 or obtain information
regarding each antenna. In use, a hand-held PDA (Personal Digital
Assistant) 209, such as a Palm Pilot.TM., may be connected to
transmission means 206 via suitable interface means 207, 208, 210
and 211 to facilitate communication between actuation means 215 to
217 and PDA 209. The current attributes of each antenna such as
downtilt, beam width and azimuth may be downloaded to PDA 209 and
adjustments made by entering data at PDA 209 and transmitting this
to actuation means 215, 216 and 217. Alternatively, settings or a
schedule of future settings may be downloaded from PDA 209 to
actuation means 215 to 217 and the antenna operates in accordance
therewith. For example, required antenna settings for different
periods may be transferred as a file from PDA 209 to each actuation
means 215 to 217 which will then operate in accordance with the
schedule.
[0122] Referring now to FIG. 20 a second control system
implementation is shown. In this case control data from
transmission means 206 is extracted via a single actuation means
224 which drives each actuator 218, 219 and 220 via dedicated
cables. Actuation means 224 is preferably provided at the top of a
structure in close proximity to antennas 203, 204, 205 to minimise
the length of cable required from actuation means 224 to antennas
203, 204 and 205. As only short connection paths are required this
is still a dramatic advantage over the need to wire from the bottom
of an antenna base station to each antenna.
[0123] Referring now to FIG. 21 the implementation is similar to
that of FIG. 20 except that control data receiving means 225
supplies serial control data to actuation means 226, 227 and 228
which extract control data relevant to that antenna and drive
actuators 218, 219 and 220. Actuation means 226, 227 and 228 may
include data transceivers for antennas 203 to 205.
[0124] Referring now to FIG. 22 an alternative embodiment is shown
where signals are supplied to the actuation means via a serial line
rather than by inserting control data onto the RF feed line. In
this case serial line 230 is connected from socket 208 to actuation
means at the top of a structure. In all cases where a direct
connection is provided, suitable lightning strike protection is
required.
[0125] As shown in the embodiment of FIG. 23 serial line 230 is
connected from socket 208 to actuation means 231 of antenna 203
which is connected via a serial line to actuation means 232 and
233. In this case the serial line is an RS 485 serial connection.
The medium for the RS 485 serial connection may be a twisted pair
cable, coaxial cable or optical fibre cable. Other suitable
protocols may include a CAN bus or a 1 Wire.TM. connection etc.
Actuation means 231, 232 and 233 control actuators 218, 219 and 220
in accordance with control data supplied via serial line 230.
[0126] Again, details of each antennas current configuration may be
downloaded from actuation means 231, 232 or 233 to PDA 209 and
operating parameters may be adjusted in real time or a file may be
downloaded from PDA to each actuation means 231 to 233 to schedule
operation of the antennas.
[0127] Referring now to FIG. 24, a second implementation of the
embodiment of FIG. 21 is shown. In this case a single actuation
means 234 directly drives actuators 218, 219 and 220 in accordance
with control data supplied via serial line 230. This arrangement is
simpler in requiring only one actuation means 234 per site rather
than one per antenna. Actuation means 234 may also include
transceivers for each antenna 203, 204 and 205.
[0128] It will be appreciated that both implementations require
only a single serial cable to be provided to an actuation means to
enable control of all antennas of an cellular antenna base station.
This simply requires new antennas to be connected at the mast head
to the actuation means without any additional cabling from the
actuation means to the base of the support structure to be
installed.
[0129] Referring now to FIG. 25 a wireless embodiment is shown. In
this embodiment a PDA 240 capable of transmitting and receiving
wireless communications communicates with actuation means 241 of an
antenna system 201. Alternatively, PDA 240 may interface with a
wireless transceiver via a port, such as a serial communication
port. As shown in FIG. 26, actuation means 241 may directly drive
actuators 218, 219 and 220 of antennas 203, 204 and 205. Wireless
communication may be via suitable radio frequency communication,
although care must be taken to avoid interference with the cellular
base station. Alternatively, optical or other wireless
communications may be employed. Infrared communications may be
utilised or an optical fibre may be connected between actuation
means 241 and a connector adapted to engage with an optical port of
PDA 240. Wireless communication has the advantage that lightning
protection is not required.
[0130] Referring now to the embodiment of FIGS. 27 and 28, PDA 242
communicates directly with each actuation means 243 to 245 to
control actuators 218 to 220 directly. This embodiment has the
advantage that each antenna 203, 204, 205 is self contained and no
additional wiring is required when each antenna is installed.
[0131] Where reference is made above to actuators 218, 219 and 220
it will be appreciated that the number of actuators used in each
antenna will vary depending upon the functionality of the antenna
i.e. whether downtilt or beam width adjustment and/or azimuth
adjustment are employed.
[0132] Power may be supplied to each actuation means by a draw off
from the RF feed lines, separate power supply lines or an
independent power supply, such as solar cells charging a battery. A
separate power line may be integrated with a serial communication
line, where utilised, and connected to each actuation means in
series. An independent power supply may be integrated into each
antenna or the actuation means.
[0133] In the embodiments described above the actuation means have
been utilised to control phase shifters in the feed path to antenna
radiating elements and may include data transceivers for the
antennas. The control system of the invention could be extended so
that the actuation means controls a number of other elements of the
antenna system. Low noise amplifiers at the top of the structure
may be actively controlled via the actuation means to adjust gain.
Filters could be actively controlled by the actuation means. In
some applications duplexers and/or diplexers may also be controlled
to switch between bidirectional to unidirectional operation or visa
versa.
[0134] It is further envisaged that the main transmitters and
receivers of a cellular base station could be provided at the top
of a structure near the antennas. A single optical link could be
utilised to convey telecommunications data as well as control data.
The actuation means could be integrated with the base station
equipment, or remain separate therefrom.
[0135] Referring now to FIG. 29 a system for remote information
acquisition or control of antenna systems is shown. In this case a
computer 250 is connected via a WAN 251 to base station 252. The
WAN may be a switched circuit or packet switched connection using
internet protocols or cellular packet protocols as required. The
base station communicates with base station network hardware 253
and an antenna control unit 254. Antenna control unit 254
communicates via LAN 255 with an antenna actuation means 256. In
the embodiment of FIG. 18, antenna control unit 254 may correspond
with transmission means 206 and actuation means 215 to 217, 224 and
225 to 228 may correspond to actuation means 256. In the embodiment
of FIGS. 23 and 24 actuation means 256 may correspond to actuation
means 231 to 233 and 234.
[0136] The embodiment of FIG. 29 enables a network operator to
control an antenna system via communications with the base station.
This enables a network operator to download information regarding
the current configuration of any antenna, to actively control the
configuration of any antenna, and to download to actuation means
256 a schedule of operation for any antenna. A table of concordance
between antenna identification means (see 221 to 223 in FIG. 19)
may be maintained at computer 250 so that a network operator can
address antennas via a network operator assigned identification
code.
[0137] Referring now to FIG. 30 a remote control system over a
standard telecommunications network is shown. In this case a device
such as a lap top 260 or PDA 261 communicates via a
telecommunications network 262 with data communications equipment
263 interface to antenna control unit 264. Data communications
equipment 263 may be a router, modem, bridge etc. Antenna control
means 264 may communicate with an actuation means 266 via LAN 265.
Actuation means 266 may correspond to actuation means 215 to 217,
224, 225 to 228, 231 to 233, 234, 241 or 243 to 245 of the
embodiments previously described. It will be appreciated that
devices 260 and 261 may communicate directly with actuation means
266 if located locally. This system enables remote data acquisition
and control by a network operator via a standard telecommunications
connection. This allows control of an antenna system remotely via a
base station or separate telecommunications channel without having
to conform to any third party hardware or protocol standard.
[0138] LANs 255 and 265 may be twisted pair, coaxial or optical
fibre serial data communication links employing a suitable
communication protocol as desired.
[0139] Referring now to FIG. 31 the graphical user interface of a
PDA will be described. It will be appreciated that the description
below is directly applicable to a computer using an input device
such as a mouse. FIG. 31 shows a number of graphical elements
illustrating beam coverage for a three sector cellular
communication site. Lobes 271, 272 and 273 illustrate the beam
coverage of the three antennas of the telecommunication site. If
lobe 271 is selected, for example by tapping the screen with a
stylus, control bars 274 and 275 may appear. By clicking the stylus
on one bar and moving it to a desired position the shape of lobe
271 may be adjusted. The shape of lobe 271 may be likewise adjusted
utilising bar 275. It will be appreciated that by adjusting bar 274
and 275 both azimuthal steering and azimuthal beam width may be
adjusted for lobe 271. The numerical value of the angle of azimuth
steering from normal and the numerical variation of beam width may
be indicated. In the example shown in FIG. 31 an azimuth steering
variation of 2.degree. is indicated by numeral 276 and a narrowing
of the beam width by 15.degree. on either side is indicated by
numerals 277 and 278.
[0140] Each lobe 271, 272, 273 may be adjusted in this way and when
a desired configuration is achieved this information may be sent to
an actuation means as described above so that the actual antenna
settings are adjusted to concur with those shown on the graphical
user interface. Likewise, the actual settings of an antenna may be
downloaded from the actuation means and displayed on the screen of
a PDA. This enables the current configuration to be displayed in an
easily comprehensible manner and for adjustments to be made via the
use of a convenient graphical user interface.
[0141] In a refinement of the method described above a means for
automatic compensation may also be provided. When one antenna is
adjusted this may result in gaps in coverage. To adjust for this
the operating parameters of the other antennas may be automatically
adjusted to ensure the required coverage is still maintained. The
required coverage and optimisation parameters may be set for each
site. The automatic compensation may automatically calculate the
required operating parameters for the antennas based on this
information. In some cases it may be necessary to provide coverage
in all directions. In other situations only certain regions may
require coverage. Within different regions different capacity may
be required. The automatic compensation means optimises the
coverage and sharing of capacity between sectors for the site
constraints.
[0142] Referring now to FIG. 32 a graphical user interface for
adjusting downtilt is shown. The graphical user interface is in the
form of control bars 281, 282 and 283 for adjusting downtilt for
each site.
[0143] Referring now to FIG. 33 a simple table display interface is
shown. In this case the beam tilt, beam azimuth and beam width may
be viewed in table form and adjusted by selecting a box and
entering a value.
[0144] Referring now to FIG. 34 a scheduling interface is shown.
Using the scheduling interface, operational parameters for the
antennas may be set utilising the graphical user interface of FIG.
31 or 33. A user may then define the periods during a week over
which that configuration is to be used. Other configurations may be
likewise identified for other periods. As shown in FIG. 34
configurations 290, 291 and 292 are seen to be scheduled for
different periods during a week. Such a schedule may be created at
a PDA, computer etc and the entire schedule may be downloaded to an
actuation means which then controls the antenna according to the
schedule.
[0145] This enables a network operator to allocate capacity to
match demand as it varies over time. This enables more efficient
use of available spectrum. Theoretical calculations indicate that
significant improvements in network capacity may be achieved
utilising such active sector control. Such controllability may
reduce the number of sites required to provide coverage to an area,
allow concentrated coverage for small geographical areas for peak
demands without providing specific coverage (e.g. to cover events
at stadiums etc). The flexibility of the system also allows
disaster coverage in case there is a failure at a site and avoids
downtime associated with site maintenance.
[0146] The present invention provides an antenna system allowing
ease of control and programmability using standard devices such as
PDAs. The system facilitates the addition of new antennas requiring
minimal additional wiring.
[0147] The invention also provides an antenna in which downtilt and
beam width, azimuth and beam width or azimuth, beam width and
downtilt of the beam of an antenna may be independently and
remotely controlled. The antenna thus allows great flexibility in
control of the beam of the antenna to actively control the region
covered by an antenna beam in a cellular communications system.
[0148] Where in the foregoing description reference has been made
to integers or components having known equivalents then such
equivalents are herein incorporated as if individually set
forth.
[0149] Although this invention has been described by way of example
it is to be appreciated that improvements and/or modifications may
be made thereto without departing from the scope or spirit of the
present invention.
* * * * *