U.S. patent application number 12/952294 was filed with the patent office on 2012-05-24 for module for an active antenna system.
Invention is credited to Peter Kenington.
Application Number | 20120128040 12/952294 |
Document ID | / |
Family ID | 46064346 |
Filed Date | 2012-05-24 |
United States Patent
Application |
20120128040 |
Kind Code |
A1 |
Kenington; Peter |
May 24, 2012 |
Module for an Active Antenna System
Abstract
A module for an active antenna system for receiving and
transmitting radio signals sealed in a housing. It comprises a
power connector placed at the outside of the housing for supplying
the module with supply power; at least one micro radio for
receiving/sending digital radio signals having a digital
down-converter/a digital up-converter and a control signal
converter. The micro radio converts the digital radio signals to
analogue RF (radio frequency) signals and vice versa and is
connected to the internal bus. At least one antenna element is
connected to the micro radio and an internal data bus for the
exchange of digital radio data and control data is connected to
micro radio and hub. By placing two or more modules next to each
other on a frame these modules form an active antenna system.
Inventors: |
Kenington; Peter; (
Chepstow, GB) |
Family ID: |
46064346 |
Appl. No.: |
12/952294 |
Filed: |
November 23, 2010 |
Current U.S.
Class: |
375/219 |
Current CPC
Class: |
H04B 1/40 20130101; H01Q
1/246 20130101; H01Q 1/1242 20130101; Y10T 29/49018 20150115 |
Class at
Publication: |
375/219 |
International
Class: |
H04B 1/38 20060101
H04B001/38 |
Claims
1. A module for an active antenna system for receiving and
transmitting radio signals, comprising: a housing; at least one
radio unit for transceiving digital radio signals; at least one
antenna element located within the housing connected to the at
least one radio unit an internal data bus for the distribution and
collection of the digital radio signals within the module; and at
least one contactless communication interface for data distribution
and collection with an adjacent module.
2. The module according to claim 1, wherein the at least one
contactless communication interface is one of inductive couplers,
capacitive couplers, electromagnetic couplers or optical
couplers
3. The module according to claim 1, wherein at least part of the
housing is electromagnetically transparent.
4. The module according to claim 1, wherein at least part of the
housing is optical transparent.
5. The module according to claim 1, further comprising a hub for
controlling the distribution and collection of the digital radio
signals within the module
6. The module according to claim 5, further comprising a control
device for switching the hub into at least one of an activated
state, in which the hub communicates with the at least one radio
unit, or a deactivated state, in which the hub does not communicate
with the at least one radio unit.
7. The module according to claim 1, further comprising at least one
feedback sampling circuit.
8. The module according to claim 1, further comprising mounting
parts for mounting the module to an external frame.
9. The module according to claim 8, wherein the mounting parts are
arranged such that the module can be placed to and displaced from
the external frame without being blocked by other modules.
10. The module according to claim 9, wherein the mounting parts are
formed such that when the module is placed to the frame the module
power connector is engaged with a counterpart supply voltage
connector of the frame.
11. The module according to claim 1, further comprising a module
power connector connectable with an external power supply external
to the housing for supplying the module with supply power.
12. The module according to claim 1 wherein the at least one radio
unit, the internal bus, and the at least one contactless
communication interface are integrated on a single circuit
board.
13. The module according to claim 1, wherein the at least one radio
unit further comprises a digital signal converter.
14. A module for an active antenna system for transceiving radio
signals, comprising: a housing, the housing comprising a housing
back, at least a first end panel of the housing and at least a
second end panel opposite to the first end panel; at least one
radio unit for transceiving digital radio signals having a digital
signal-converter at least one antenna element located in the
housing connected to the at least one micro radio an internal data
bus for the exchange of digital radio signals with the at least one
radio unit and a hub; at least a first communication interface
being connected to the internal bus and placed at the first end
panel for exchanging digital data in case another module is placed
next to the first end panel at least a second communication
interface being connected to the internal bus and placed at the
second end panel for exchanging data in case another module is
placed next to the second end panel.
15. A method for manufacturing a module comprising the steps of
connecting at least one radio unit for transceiving digital radio
signals having a digital signal-converter; whereby the at least one
radio unit converts the digital radio signals to analogue RF (radio
frequency) signals and vice versa, to an internal data bus;
connecting at least one antenna element to the at least one radio
unit; connecting at least one contactless communication interface
for data distribution and collection to an adjacent module to the
internal bus.
16. An active antenna system for receiving and transmitting radio
signals comprising at least a first module and a second module,
each one of the first module and the second module sealed in a
housing; each one of the first module and the second module
comprising: at least one radio unit for transceiving digital radio
signals having a digital signal converter; at least one antenna
element located within the housing connected to the at least one
radio unit; an internal data bus for collection and distribution of
digital radio signals with the at least one radio unit; at least
one contactless communication interface for data exchange to an
adjacent module.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is related to U.S. patent application Ser.
No. 12/339,239 "Antenna Array System" filed on 17 Jul. 2007, the
contents of which are incorporated by reference.
FIELD OF THE INVENTION
[0002] This field of the present application relates in general to
a module for an active antenna system and, in particular, for a
module of an active antenna system used in a mobile communication
system. The field of the application also relates to a method of
manufacturing a module for an active antenna array as well as an
active antenna array.
BACKGROUND OF THE INVENTION
[0003] The use of mobile communications networks has increased over
the last decade. Operators of these mobile communications networks
have increased the number of base transceiver stations in order to
meet an increased demand for service by users of the mobile
communications networks. The operators of the mobile communications
network wish to purchase components for the base transceiver
stations at a lower price and also wish to reduce the running costs
of the base station. Active antenna systems have proven to meet
these goals.
[0004] The term "base transceiver station (BTS)" in the context of
this disclosure includes, but is not limited to, base stations, as
known from GSM networks, as well as a node B (known from UMTS/3G
networks) or enhanced node B, and similar units used in other
mobile communication network.
[0005] The term "subscriber device" in the context of this
disclosure is intended to encompass all types of mobile stations
and other devices connected to the mobile communication network.
Such subscriber devices can be portable or stationary. For example
wireless modules can be incorporated into vending machines for the
transceiving of data over the mobile communication network. Such
wireless modules are also considered to be subscriber devices.
[0006] An active antenna system is known, for example, from the
Applicant's co-pending international application PCT/EP2007/006334
and U.S. patent application Ser. No. 12/339,239, which is published
as US Patent Application Publication No. US 2009/0252205. In the
known active antenna system, the antenna is formed by a plurality
of antenna elements. At least one of the antenna elements is
directly connected to a dedicated radio unit. However, two or more
of the antenna elements may be coupled to a single radio unit, for
example by a Wilkinson coupler. As the digital radio unit is formed
by a plurality of the radio units which are placed close to the
antenna elements no coaxial cable is required in order to couple
the digital radio unit to the antenna elements, especially if the
radio units are arranged on the same printed circuit board or even
monolithically integrated by micro-electronic means or as a
multi-chip module.
[0007] The radio units comprise at least one filter to separate
downlink signals and uplink signals, e.g. transmit signals and
receive signals. A receive signal is converted into a digital
band-pass signal by a low-noise analogue-to-digital converter. The
digital band-pass signal is down-converted into a digital base-band
signal by a digital down converter, which is integrated in a
digital transceiver. In order to generate the transmit signal a
digital base-band signal is up-converted by a digital up-converter
and transferred by a digital-analogue converter into a RF signal.
Each one of the radio units is connected via a so-called C-Hub
through an optical fibre to a base station. The C-hub converts the
transmit signals and receive baseband signals into optical signals
for transmission along the optical fibre according to a CPRI or
OBSAI (or similar) standard interface. These optical signals are
then transferred via the optical fibre to a digital radio server
located at the base station. The optical fibre thereby may be up to
40 km long, enabling the remote location of the base station with
respect to the antenna elements mounted on a tower-top.
[0008] The radio units, the C-hub and the antenna elements are
arranged in one common housing. The common housing is usually
mounted on the tower top of an antenna mast and is therefore part
of the so-called tower-top equipment. Typically the active antenna
system may comprise sixteen antenna elements, but this number is
not limiting. The active antenna system with sixteen antenna
elements may weigh up to 40 kg.
[0009] As the active antenna system contains active circuit
elements, the risk of failure is higher than for purely passive
antennas. The mobile communications network operators are generally
hostile to the idea of having to replace the entire active antenna
system in the event of a failure, even if the mobile communications
operators can schedule and/or delay this replacement until a number
of the modules have failed. The expense and time involved in a
crane-based replacement of the active antenna system at a cell site
may be a disincentive to the adoption of active antenna
systems.
SUMMARY OF THE INVENTION
[0010] It is an aspect of the teachings of this disclosure to
provide a module for an active antenna system to enable a splitting
of an active antenna arrangement into at least two separate
modules. Each one of the separate modules is substantially sealed
in a weather-proof housing. Each one of the separate modules may
also comprise a power connector placed at the outside of the
housing for supplying the module with supply power. It is,
possible, to supply the module with supply power by other means.
The active antenna system further comprises at least one radio unit
for transceiving digital radio signals having a digital
down-converter/a digital up-converter and a control signal
converter. The at least one radio unit converts the digital radio
signals to analogue RF (radio frequency) signals and vice versa.
The at least one radio unit is connected to the internal bus and at
least one antenna element connected to the at least one radio unit.
The module further comprises an internal data bus for collection
and distribution of digital radio data and control data with the at
least one radio unit as well at least one contactless
communications interface.
[0011] In one aspect of the invention, the module also includes a
hub that controls the collection and distribution of the digital
radio data and control data. The hub may be switchable on and off
so that in some implementations of the invention a single central
hub controls the collection and distribution of the digital radio
data and control data in different ones of the modules. In another
implementation of the invention, each one of the modules has its
own hub for controlling the collection and distribution of the
digital radio data and control data in its own module as well as
between the modules.
[0012] Each one of the modules weighs less than the active antenna
arrangement in total and so each module is easier to handle by
service personnel. If each one of the modules weighs less than 15
kg, the majority, if not all of, health and safety requirements
world-wide for single-man lift/deployment operations at height are
met. The service personnel can exchange single modules or all of
the modules one by one on an antenna mast, without the need of a
crane. This is in contrast to the active antenna system of the
prior art that is contained in a single housing. The single housing
of the prior art is so heavy that a crane has to be used to
exchange the active antenna system as a whole.
[0013] Another aspect of the teachings of this application is that
the module comprises at least one contactless communication
interface for data collection and distribution between two or more
adjacent modules. The contactless data exchange between the modules
removes the need for plugs and sockets between adjacent ones of the
modules. These plugs and sockets, in the field, might be a source
of contact problems due to their exposure to weather and hence of
unreliability for the active antenna system as a whole. It is less
time-consuming for the service personnel to exchange the module, as
the service technician does not have to carefully align and
weather-proof seal the plugs and sockets to connect the adjacent
modules. This reduces another source of error as well as reducing
the time for the exchange of the module.
[0014] Another aspect of the teaching of this application is that
the module is equipped on the outside of the housing with mounting
parts which are formed such that when the module is slid into a
frame the supply voltage connector is engaged with a counterpart
supply voltage connector of the frame. As each of the modules is
equipped with a power supply connector that engages with the power
supply connector of the frame the module is mounted to, there is no
need to connect one module with another module for the purpose of
distributing a power supply. In this case the power supply is
distributed over the frame to each one of the modules and the
adjacent modules do not need to be connected directly to each
other.
[0015] Another aspect of the teaching of this application is that
the at least one radio unit, the internal bus, and the at least one
interface are integrated on a single circuit board.
[0016] Another aspect of the teaching of this application is a
method for manufacturing the module of an active antenna
system.
DESCRIPTION OF THE FIGURES
[0017] FIG. 1 shows a first aspect of the module according to the
present disclosure.
[0018] FIG. 2 shows a further aspect of the module according to the
present disclosure.
[0019] FIG. 3 shows yet another aspect of the module according to
the present disclosure.
[0020] FIG. 4 shows yet another aspect of the module according to
the present disclosure.
[0021] FIGS. 5a, 5b and 5c show another aspect of the module
according to the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0022] The invention will now be described on the basis of the
drawings. It will be understood that the embodiments and aspects of
the invention described herein are only examples and do not limit
the protective scope of the claims in any way. The invention is
defined by the claims and their equivalents. It will be understood
that features of one aspect or embodiment of the invention can be
combined with a feature of a different aspect or aspects and/or
embodiments of the invention.
[0023] FIG. 1 shows a first aspect of the module according to the
present disclosure. An active antenna system 1 comprises a first
module 11, a second module 12, and a third module 13 attached to an
antenna mast 2. In this aspect of the present disclosure the three
modules (the first module 11, second module 12 and the third module
13) commonly form the active antenna system 1. The person skilled
in the art will appreciate that the active antenna system 1 may be
arranged only with two modules or even by four or more modules. The
person skilled in the art will strive to split the active antenna
system 1 into the fewest possible number of modules. At the time of
the present disclosure the active antenna system 1 with sixteen
antenna elements was implemented and its weight was under 40 kg.
The active antenna system 1 according to the present disclosure is
designed to fit into the three modules 11, 12 and 13. The weight of
each one of the three modules 11, 12 and 13 is envisioned to not
exceed 15 kg; that is the weight that most health and safety
requirements accept for deployment/lift of equipment at height by a
single person. It will be appreciated that the modularisation of
the active antenna system 1, as described in this disclosure, does
add slightly to the overall weight of the active antenna system 1,
however this disadvantage is outweighed by the previously mentioned
advantages.
[0024] In the active antenna system 1 payload signals and control
signals are sent and received from a base station equipment rack 3
in digital form. The payload signals and the control signals can be
exchanged via a fibre optic cable 4 up to 40 km in length. The base
station equipment rack 3 can be located in a remote place. Only a
power supply cable 5 has to supply the active antenna system 1 with
power from a power supply unit 6 located proximally. In the event
that the base station equipment rack 3 is also very close to the
active antenna system 1, the power supply unit 6 may also be
incorporated in the base station equipment rack 6. The active
antenna system 1 and the base station equipment rack 3 together
form a traditional base transceiver station. The active antenna
system 1 and the base station equipment rack 3 may together form a
logical unit but the active antenna system 1 and the base station
equipment rack 3 may be located physically apart from one
another.
[0025] FIG. 2 shows another aspect of the present disclosure with
the active antenna system 1 depicted sideways. A frame 21 is
attached to the mast 2. In turn the first module 11, the second
module 12 and the third module 13 are attached to the frame 21.
Usually more than one frame is attached to the mast 2 so as to
deploy more than one active antenna system 1 for supplying
different directions from one mast 2. The mounting frame 21 is
attached to the mast 2 when the modular active antenna system 1 is
first installed and the modules are then attached to this mounting
frame 21. The mounting frame 21 may also be formed in a way to
support mechanical downtilt requirements, in addition to electronic
downtilt capabilities of the active antenna system 1. Suitable
mounting spacers (not shown) may be used for example to offset the
mounting frame 21 from the mast 2 and to provide any required fixed
tilt. The fibre optic cable 4 is not shown in FIG. 2 for
simplicity.
[0026] The mechanical mounting of the active antenna system 1 is
arranged in a way that each of the first module 11, the second
module 12 or the third module 13 can be mounted and de-mounted
without the need to de-mount any one of the other two modules.
Depending on the chosen support the first module 11, the second
module 12 or the third module 13 may, for example, be slid in and
out or pivoted in and out of the frame 21. In the present
disclosure each of the first module 11, the second module 12 or the
third module 13 has mounting means only on the back side 113 of
their respective module housing, so that the first module 11, the
second module 12 or the third module 13 are attached only to the
frame 21 but not to each other. Once mounting means like screws
have been de-mounted on the backside of the housing of a module 11,
the module 11 can be moved, horizontally outwards from the frame.
Thus for example, the upper-most module 13 does not need to be
removed as a part of the process in replacing the centre module
12.
[0027] On the frame 21 are located in predetermined positions power
plugs 22 which correspond to power plugs 110 that extend from or
into the backside 113 of the housing of first module 11, the second
module 12 or the third module 13. In the event that the module 11
is mounted to the frame 21 the power plug 22 of the module 11 and
the power plug 22 mounted to the frame 21 engage and can then be
sealed to be weatherproof. As all of the power plugs 22 that are
attached to the frame 21 are connected with the power supply cable
5, each one of the first mounted module 11, the mounted second
module 12 or the mounted third module 13 is supplied with power
independently of the other modules.
[0028] The fibre optic cable 4 is connected to at least one of the
first module 11, the second module 12 or the third module 13. The
connection of the fibre optic cable 4 is carried out by, for
example, an SFP (small form factor pluggable) module as is known in
the art. The purpose of the SFP module (not shown in the Figs) is
to convert the light signals passing through the fibre optic cable
4 from light into data signals in the module 11, 12 or 13. The SFP
module therefore comprises a least a photodiode and suitable
electronics. It will be noted that the SFP module only converts the
light signals to electronic signals. The SFP module does not
process either the light signals or the electronic signals. In most
cases, the SFP module will be bi-directional, that is to say that
the SFP module is capable of transmitting light signals back to the
base transceiver station as well as receiving light signals from
the base transceiver station. In this aspect, the SFP module will
also contain a laser source, typically a laser-emitting diode, and
suitable electronics to drive this laser-emitting diode with
digital data signals.
[0029] It would be possible to connect the fibre optic cable 4 to
all of the first module 11, the second module 12 or the third
module 13, but this is generally not required in practice. It would
be possible to equip all of the first module 11, the second module
12 or the third module 13 with an SFP module and only use one of
the SFP modules, for example in the bottommost module--in the
aspect shown in FIG. 2 this would be the third module 13. It would
also be possible to equip one or more of the first module 11, the
second module 12 or the third module 13 with more than one SFP
module. For example a first one of the SFP modules would be used
for signals operating using a GSM protocol and a second one of the
SFP modules would be used for signals operating using a UMTS
protocol. This would require either multiplexing of the light
signals along the fibre optic cable 4 or the provision of two
separate fibre optic cables 4.
[0030] FIG. 3 shows the electrical structure of one of the first
module 11, the second module 12 or the third module 13. For
simplicity, the first module 11 will be chosen to illustrate the
electrical structure. Each module 11 comprises a plurality of micro
radio units 111. Each one of the micro radio units 111 is connected
at least to one antenna element 112. In the present disclosure each
one of the micro radio units 111 is connected to exactly one
antenna element 112, but the person skilled in the art will
appreciate that the micro radio unit 111 may be connected, for
example by means of a hybrid coupler to two or more of the antenna
elements 112. The micro radio units 111 are transceivers that
transmit the radio signal to be sent in the downlink and receive
radio signals in the uplink. In the present disclosure each one of
the micro radio units 111 comprises a bidirectional serial
interface connected to an internal bus 115.
[0031] The bidirectional link between the micro radio units 111 and
a so called C-hub 113 is based on the well known standard termed
"SerDes". The SerDes functionality basically comprises
parallel-to-serial as well as serial-to-parallel conversion,
channel coding and decoding plus clock recovery and
synchronization. A signal received in the micro radio unit 111 is
converted from its analogue form into digital samples that are
transmitted to the C-hub 113 via an internal bus 115. Similarly the
bidirectional interface of each one of the micro radio units 111
extracts from the internal bus 115 the data that is destined for
that specific micro radio unit 111 and converts the data samples
into an analogue radio signal to be transmitted over the attached
antenna element 112.
[0032] The C-hub 113 converts a CPRI/OBSAI downlink signal received
at the CPRI/OBSAI terminal 114 and supplies the converted signals
in an appropriate time frame and distributes them in the "SerDes"
Format via the internal bus 115 to the micro radio units 111.
Similarly received uplink signals from the micro radio units 111
are arranged in an uplink data stream that is sent by the C-Hub 113
via the CPRI/OBSAI terminal 114 to the remote base transceiver
station.
[0033] Optionally a so-called micro sniffer 118 can be inserted
between the C-Hub 113 and the CPRI-terminal 114. The micro sniffer
118 is a special micro radio unit with inverse receive and
transceiver band for monitoring and calibrating purposes. The micro
sniffer 118 transmits pilot signals towards and detects the
radiation emitted from the antenna elements 112, thus providing the
C-hub 113 with feedback control operation as required by the micro
radio units 111 for calibration purposes. More detailed information
on the interaction of micro radio units 111, serial interface 115
and C-hub 113 can be found in U.S. patent application Ser. No.
12/339,239 wherein this concept was presented.
[0034] In this aspect of the present disclosure two inter-module
interfaces 116, 117 are connected to the internal bus 115. By means
of the two inter-module interfaces 116, 117 the internal bus 115
can be extended to an internal bus of at least the second module 12
that is placed in the vicinity of the first module 11.
[0035] The C-hub 113 may or may not be present in all of the first
module 11, the second module 12 or the third module 13. In practice
only one C-hub 113 in one module is required to control the
collection and distribution of the data signals along the internal
bus and to the other ones of the modules. It is possible for
manufacturing simplicity to provide all of the first module 11, the
second module 12 or the third module 13 with the C-hub 113 and then
switch off non-required ones of the C-hub 113 in other modules. It
is also possible to operate all of the C-hubs 113 in all of the
first module 11, the second module 12 or the third module 13. The
provision of the C-hub 113 in each of the modules enables each one
of the C-hubs 113 to made using a small FPGA as each one of the
C-hub 113 would effectively take over 1/3 of the performance of a
central or master C-hub in a single one of the modules 11, 12,
13.
[0036] FIG. 4 shows another aspect of the present disclosure, where
the second module 12 and the third module 13 are placed adjacent to
each other. In the three dimensional FIG. 4 the part of the housing
that forms the longest side of the housing is located on the front
side 1201, 1301 of the second module 12 and third module 13
respectively. In order to demonstrate that the arrangement of the
second module 12 and the third module 13 can be chosen in any
appropriate alignment, the second module 12 and the third module 13
are placed horizontally adjacent to each other, so that the second
module 12 is on the left side of the third module 13. A person
skilled in the art will also appreciate that the modules 11, 12 and
13 may be arranged more generally as a matrix, for example as two
modules horizontally and three modules vertically, resulting in an
active antenna array 1 composed of six modules.
[0037] In FIG. 4 the second module 12 comprises, on a right side of
its housing 1203, a third interface 126 and the third module 13
comprises on a left side of its housing 1302 a fourth interface
137. Electrically the third interface 126 and the fourth interface
137 are identical to the first interface 116 and the second
interface 117 of the first module 11 shown in FIG. 3. The third
interface 126 and the fourth interface 137 are designed for near
field communication purposes and are directed such that only
adjacent ones of the third interface 126 and the fourth interface
137 communicate with each other. The second module 12 and the third
module 13 may comprise further interfaces to communicate with
further modules either placed to the right of the second module 12,
to the left of the third module 13 or on top of the second module
12 or the third module 13, or below the second module 12 or third
module 13. For the purpose of providing the interfacing capability
for a matrix of modules, each one of the modules may provide an
interface on its top side of the housing 1204, the bottom side of
its housing 1205, the left side of its housing 1202 and the right
side of its housing 1203.
[0038] In FIG. 4 the third interface 126 and the fourth interface
137 are chosen to be optical interfaces establishing a
bi-directional optical link 7 between the second module 12 and the
third module 13. The optical link 7 may be in the infrared range of
light. Due to the optical link 7 at least part of the housing, or
all of the end-panels on the left and right side of the housing
have to be transparent in order to allow the optical link to pass
from one module to an adjacent module, whilst still permitting the
modules themselves to be factory sealed and thereby reliable from
an environmental ruggedness perspective. The internal bus of the
second module 12 is extended via this optical link 7 to the
internal bus of the third module 13.
[0039] The extension of the internal bus means that only one of the
C-hubs 113, either in the second module 12 or the third module 13,
is needed to distribute and collect data between all the micro
radio units 111 in the second module 12 and the third module 13 and
the remote base transceiver station 3. In the aspect shown in FIG.
4, for example, the second module 12 comprises a C-hub 113. The
third module 13 may be delivered in a second version of the module
without a C-hub 113, or be supplied with a second C-hub 113. This
second C-hub 113 is not necessary for the function of the active
antenna system 1. The person skilled in the art may decide, as
noted above, to implement a C-hub 113 in each one of the modules,
as this may simplify the C-hub 113 and/or reduce the number of
different modules to be produced and to be held in storage as spare
parts. In the case that all of the modules are identical and all of
the modules provide a C-hub 113, in case of failure of a C-hub 113,
the defective C-hub may be deactivated remotely and one the other
C-hubs can take over the task of the defective C-hub 113.
[0040] The choice of which one of the C-hubs 113 in which one of
the modules 11, 12 or 13 is activated can be decided on a number of
factors. In practice any one of the C-hubs 113 will be able to
address any one of the micro radio units 111. The choice of the
master or central C-hub 113 can either be pre-programmed or decided
by a process of auto-negotiation.
[0041] The person skilled in the art will also consider, in a
specific application, if it is more efficient to exchange other
control information like status control, status messages, warnings
and alarms over one interface by multiplexing the information with
the data of the internal bus 115, or to provide at least a second
link in parallel by a control interface purely for the exchange of
the other information.
[0042] FIGS. 5a, 5b and 5c show other aspects of the present
disclosure in which the inter-module interfaces use electromagnetic
transmission from a first inter-module interface in a first module
11 to a second inter-module interface in a second module 12. In
this aspect of the present disclosure the signals are coupled
electromagnetically. In this aspect the housing material of the
housing needs to be electromagnetically transparent, but may be
optically non-transparent. This means that virtually any form of
plastic could be used given the extremely short transmission
distance between the two modules that are mounted adjacent to each
other. The selection of the housing material is therefore
simplified and could be selected primarily for mechanical strength,
cost and environmental longevity without needing to worry too much
about its electromagnetic properties.
[0043] As one aspect of electromagnetic transmission, FIG. 5a shows
the use of inductive coupling between a first interface 116 in the
first module 11 and a second interface 217 located in the second
module 12. This inductive coupling can take many forms. FIG. 5a
shows one non-limiting example of inductive coupling. A first coil
71 is connected to the first interface 116 and a second coil 72 is
connected to the second interface 217. When the first interface 116
and the second interface 127 are placed adjacent to each other both
of the first coil 71 and the second coil 72 commonly form a
transformer 70 with a primary winding and a secondary winding. If
the first interface 116 is transmitting the first coil 71 of the
first interface 116 forms a primary winding and the second coil 72
of the second interface that is receiving forms a secondary
winding. If the second interface 217 is transmitting the roles
change and the second coil 72 is the primary winding and the first
coil 71 is the secondary winding of that transformer 70. The
signals flowing in the primary windings induce corresponding
signals in the secondary winding. The induced signals can then be
processed, e.g. by amplifying and discriminating the amplified
signal. As signals on the first internal bus 115 are transmitted by
the first interface and second interface to the second internal bus
215 and vice versa, the first internal bus 115 and the second
internal bus 215 behave like a single bus and transmit the
information to and from each micro radio unit 111 to one or more of
the C-hubs 113, as noted above.
[0044] It will be appreciated that it may be opportune to provide
two separate inductive couplings between two of the modules 11, 12
and 13, for example on opposite sides of the antenna housing. This
will enable one of the two separate inductive couplings to transfer
the signals in one direction and other one of the two separate
inductive couplings to transfer the signals in another direction.
Each one of the separate inductive couplings would thus form a
unidirectional link.
[0045] As another aspect of the electromagnetic interfaces, FIG. 5b
shows a capacitive coupling arrangement, in which the end panels
1103, 1202 of the modules 11, 12 together form a dielectric between
a first plate 81 and a second plate 82 of a capacitor 80. The first
plate 81 of the capacitor 80 is within the first module 11 and is
electrically connected to the first inter-module interface 116. The
second plate 82 of the capacitor 80 is within the second module 12
and is electrically connected to the second inter-module interface
217. The first plate 81 and the second plate 82 might be formed by
a foil of metal attached on the insides of the modules housings to
the end panels 1103, 1202. This arrangement functions like any
other capacitor, passing alternating current signals through a
dielectric. In this case the material of the end panels, due to
dielectric losses, influence the signal strength that is received
at the other end of the capacitor.
[0046] It will also be appreciated that two separate capacitive
coupling arrangements may be provided between two of the modules
11, 12 and 13 which enable each one of the two separate capacitive
couplings to transfer the signals in different directions. Each one
of the two separate capacitive couplings is therefore a
unidirectional link.
[0047] As another aspect of the electromagnetic interfaces FIG. 5c
shows the use of radiation. The first inter-module interface 116 in
the first module 11 is connected with a first antenna 91 and the
second inter-module interface 217 in the second module 12 is
connected to a second antenna 92. The first antenna 91 and the
second antenna 92 are each placed in the inside of the housing of
the first module 11 and the second module 12 and are operated in
their near-field. Similarly there may be two different antennas in
each one of the modules for transmitting radiation in only one
direction (thus forming the unidirectional link). One of the two
different antennas transmits the radiation in one direction and
another one of the two different antennas transmits the radiation
in another direction.
[0048] In this aspect of the present disclosure three modules form
an active antenna system 1, each one of the three modules
comprising six antenna elements. This arrangement comprises
eighteen antenna elements in total. The non-modular active antenna
systems in one housing known at the time of the disclosure have
sixteen antenna elements. The modularized active antenna system 1
of this disclosure has therefore two antenna elements in excess of
the usual number of antenna elements. The person skilled in the art
may decide to offer two types of modules with a different number of
antenna elements, for example to provide an active antenna system
of two modules with six antenna elements and one module that only
provides four antenna elements. If the modules with the six antenna
elements are used as the top and the bottom module, one could also
chose not to implement the second communications interface for the
top module and the bottom module, as only a module in the middle
needs two communication interfaces to extend the internal bus to
both sides, i.e. to the top and the bottom, or to the left and to
the right. Although by economising two antenna elements and two
micro radio units 111, and maybe even one communications interface,
in the end the production and delivery of two different type of the
modules may be more costly than providing only one single type of
module. The person skilled in the art may even prefer three
identical modules, as this provides two spare micro radio
interfaces and two spare antenna elements which could be used as
redundancy in the event that one of the other sixteen micro radio
units/antenna elements fails.
[0049] The present disclosure further relates to a computer program
product embedded on a computer readable medium. The computer
program product comprises executable instructions for the
manufacture of the module of the present disclosure.
[0050] While various embodiments of the present invention have been
described above, it should be understood that they have been
presented by way of example, and not limitation. It will be
apparent to persons skilled in the relevant arts that various
changes in form and detail can be made therein without departing
from the scope of the invention. Thus, the present invention should
not be limited by any of the above-described exemplary embodiments,
but should be defined only in accordance with the following claims
and their equivalents.
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