U.S. patent application number 14/174913 was filed with the patent office on 2014-06-12 for master unit, remote unit and multiband transmission system.
This patent application is currently assigned to ANDREW WIRELESS SYSTEMS GMBH. The applicant listed for this patent is ANDREW WIRELESS SYSTEMS GMBH. Invention is credited to OLIVER BRAZ, STEFAN EISENWINTER, MATHIAS SCHMALISCH, PETER SCHMID, JOERG STEFANIK.
Application Number | 20140161162 14/174913 |
Document ID | / |
Family ID | 43708742 |
Filed Date | 2014-06-12 |
United States Patent
Application |
20140161162 |
Kind Code |
A1 |
BRAZ; OLIVER ; et
al. |
June 12, 2014 |
MASTER UNIT, REMOTE UNIT AND MULTIBAND TRANSMISSION SYSTEM
Abstract
A master unit and a remote unit is provided for a multiband
transmission system for distributing and combining signals of at
least one wireless communication network and at least one digital
network. A reference frequency generator is arranged in the master
unit, the reference frequency generator being designed to clock a
master modem for converting the signals of the at least one digital
network. The reference frequency signal emitted by the reference
frequency signal is restored via a reference frequency receiver and
is used for closing a remote modem that is located there for
demodulation.
Inventors: |
BRAZ; OLIVER; (MONHEIM,
DE) ; EISENWINTER; STEFAN; (BUCHDORF, DE) ;
SCHMALISCH; MATHIAS; (AUGSBURG, DE) ; STEFANIK;
JOERG; (DONAUWOERTH, DE) ; SCHMID; PETER;
(NEUHAUSEN, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ANDREW WIRELESS SYSTEMS GMBH |
BUCHDORF |
|
DE |
|
|
Assignee: |
ANDREW WIRELESS SYSTEMS
GMBH
BUCHDORF
DE
|
Family ID: |
43708742 |
Appl. No.: |
14/174913 |
Filed: |
February 7, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13471032 |
May 14, 2012 |
8681916 |
|
|
14174913 |
|
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|
|
PCT/EP2010/006797 |
Nov 9, 2010 |
|
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|
13471032 |
|
|
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Current U.S.
Class: |
375/222 |
Current CPC
Class: |
H04L 7/06 20130101; H04W
88/085 20130101; H04B 7/15542 20130101 |
Class at
Publication: |
375/222 |
International
Class: |
H04W 88/08 20060101
H04W088/08; H04L 7/06 20060101 H04L007/06 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 12, 2009 |
DE |
102009052936.5 |
Claims
1. A master unit, comprising: a master downlink interface for
receiving a data signal to be wirelessly transmitted; a master
modem for converting the data signal into a coded digital data
signal; a reference frequency generator for generating a reference
frequency signal, wherein the master unit is configured for
combining the coded digital data signal with the reference
frequency signal to form a combined coded digital signal; and a
master transmission unit for transmitting the combined coded
digital signal on a wired transport link.
2. The master unit according to claim 1, wherein the combined coded
digital signal includes a digitized radio frequency signal from a
base transceiver station.
3. The master unit according to claim 1, wherein the data signal is
associated with one of a radio frequency communications network and
a wired digital communications network.
4. The master unit according to claim 1, wherein the reference
frequency signal is usable for modem clocking the master modem.
5. The master unit according to claim 1, wherein the reference
frequency generator is configured to concomitantly provide the
reference frequency signal for combining with the coded digital
data signal and to the master transmission unit as an uncombined
reference frequency signal.
6. The master unit according to claim 1, further comprising a
spread sequence generator connected downstream of the reference
frequency generator and being configured to spread the data
signal.
7. The master unit according to claim 1, further comprising a
spread sequence generator connected downstream of the reference
frequency generator and being configured to spread the reference
frequency signal.
8. The master unit according to claim 1, wherein the master
transmission unit is configured to transmit digital baseband data
on the combined coded digital signal.
9. The master unit according to claim 1, wherein the master modem
is configured for a QAM or an FSK modulation/demodulation.
10. The master unit according to claim 1, further comprising a
master uplink interface for receiving a combined uplink signal from
a remote unit and for communicating with a base station of at least
one wireless communication network.
11. The master unit according to claim 1, further comprising a
master uplink splitter for splitting an uplink coded digital signal
from the combined coded digital signal.
12. A remote unit, comprising: a remote downlink interface for
receiving a combined coded digital signal from a master unit via a
wired transport link, the combined coded digital signal including a
downlink coded digital data signal and a reference frequency
signal; a remote modem for converting the downlink coded digital
data signal into a downlink data signal; and a remote downlink
interface for transmitting the downlink data signal to a network
terminal of a wireless communication network.
13. The remote unit according to claim 12, further comprising: a
remote uplink interface for receiving an uplink data signal from
the network terminal of the wireless communication network, wherein
the remote modem is configured to convert the uplink data signal
into an uplink coded digital data signal; and a remote transmission
unit for transmitting the uplink coded digital data signal.
14. The remote unit according to claim 12, wherein the reference
frequency signal is usable for clocking the remote modem using the
reference frequency signal for modulating and demodulating data
signals.
15. A method, comprising: receiving a data signal for being
wirelessly transmitted; generating a reference frequency signal;
and transmitting a combined signal on a wired transport link, the
combined signal included an coded digital data signal and the
reference frequency single, the coded digital data signal being
formed from the data signal.
16. The method according to claim 15, wherein receiving a data
signal includes receiving a digital downlink data signal from a
base station associated with one of a radio frequency
communications network or a wired digital communications
network.
17. The method according to claim 15, further comprising spreading
at least one of the data signal or the reference frequency
signal.
18. The method according to claim 15, wherein the master
transmission unit is configured to transmit digital baseband data
that is included in the combined coded digital signal.
19. The method according to claim 15, further comprising converting
the data signal into the coded digital data signal.
20. The method according to claim 15, further comprising using the
reference frequency signal to clock a modem in converting the data
signal into the coded digital data signal.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation application of U.S. patent
application Ser. No. 13/471,032, which was filed on May 14, 2012,
which is a continuation of International Application No.
PCT/EP2010/006797, which was filed on Nov. 9, 2010, and which
claims priority to German Patent Application No. DE 10 2009 052
936.5, which was filed in Germany on Nov. 12, 2009, and all of
which are herein incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a master unit and to a remote unit
for distributing and combining signals of at least one wireless
communication network and of at least one digital network. The
invention further relates to a multiband transmission system with a
master unit of this type and with a remote unit of this type.
[0004] 2. Description of the Background Art
[0005] A multiband transmission system of the above-mentioned type
is basically used for distributing and combining signals of at
least one wireless communication network and of at least one
digital network. The master unit is hereby used for relaying and
amplifying signals between a base station and the remote unit. The
remote unit is set up for communication with the end user, in
particular by means of a mobile terminal. The communication is
hereby carried out bi-directionally. This is referred to as a
downlink direction with a signal propagation direction from the
base station or the master unit to the remote unit or to the end
user and an uplink direction in the case of a signal propagation
direction from the end user to the master unit or to the base
station.
[0006] The master unit is radio-connected or cable-connected to the
base station and transmits in the downlink direction and
respectively receives in the uplink direction signals of different
mobile communication standards in different frequency bands, such
as GSM, DCS, UMTS, LTE, AWS, PCS, WiMAX, etc. In addition, data or
signals of a digital communication network, such as digital video
data or audio data, DVD, etc. are exchanged. The respectively
received signals are processed in the master unit, in particular
amplified, and relayed to a remote unit in the downlink direction
or received therefrom in the uplink direction. The signals of the
wireless communication network are transmitted to the end user or
received therefrom via the remote unit. Likewise, the end user can
communicate in a cable-connected manner within the digital network
via the remote unit, in particular exchange data between the
terminals connected to the network, for example, computers, control
devices, televisions etc. or control devices hereby.
[0007] A remote unit is provided, for example, for different rooms
or floors of a building in order to achieve a locally sufficient
signal strength for the end user. A central master unit hereby
supplies in particular a plurality of remote units. To separate the
two signal propagation directions, generally the two techniques FDD
(Frequency Division Duplexing) and TDD (Time Division Duplexing)
are known.
[0008] In the transmission of signals between the master unit and
the remote unit by means of frequency division duplexing, and in
particular also with the simultaneous transmission of digital and
analog signals, an undesirable intermodulation between the
frequency bands used can occur. The signal quality is impaired as a
whole hereby. A clean separation of the frequency bands on the
receiver side may be no longer possible. These problems have
already been discussed, for example, in the IEEE Transactions on
Communications, Vol. COM-24, No. 9, September 1976, page 1008 et
seq.
[0009] From U.S. Pat. No. 7,336,680 B2 an architecture is known for
a multiband transmission system for transmitting frequency
multiplexed signals of different standards according to a
point-to-point configuration. For a bi-directional communication
between a central unit and an end user frequencies are
statistically assigned to the individual frequency channels and a
point-to-point connection channel is hereby created. A certain
frequency is thereby assigned to the signals with highest priority.
The frequencies of the other signals are assigned dynamically. The
data of different standards are thus transmitted by corresponding
modulation within the assigned frequency bands. The frequencies
themselves are not converted.
[0010] From U.S. Pat. No. 7,088,921 B1 a system is known for
transmitting Ethernet data via a passive optical network in a
point-to-multiple point system. Although to avoid collisions in the
uplink direction the Ethernet data are modulated with the aid of an
FSK modulator to a carrier signal here, the combination of the
different uplink data streams takes place only after the
electro-optical conversion.
[0011] From US 2008/0192855 A1 a system is known for transmitting
so-called MIMO signals. MIMO here stands for the abbreviation
"multiple input multiple output," wherein several antennas
spatially separated from one another are used to increase the radio
transmission rate within a frequency or within a frequency band. In
US 2008/0192855 A1 for the separation of the MIMO signals of the
same frequency it is provided to separate them from one another by
frequency conversion and subsequently to transmit them jointly in a
cable-connected manner. In particular one of the MIMO signals is
hereby transmitted at the same frequency. The other MIMO signals
are frequency-converted suitably accordingly to prevent an
intermodulation. To reestablish the original MIMO signals by a
frequency shift-back, a reference signal is concomitantly
transmitted.
[0012] Also from U.S. Pat. No. 5,339,184 a multiband transmission
system is known for transmitting a plurality of radio signals of
different frequencies. There the frequency bands of all signals of
different frequencies are converted to an identical number of
non-overlapping frequencies or frequency bands. The signals of the
non-overlapping frequency bands are transmitted optically between a
master unit and a remote unit. After the transmission in both
directions, the frequencies are respectively reconverted again.
SUMMARY OF THE INVENTION
[0013] It is therefore an object of the present invention to
disclose an improved multiband transmission system compared to the
prior art for distributing and combining signals of at least one
wireless communication network and of at least one digital network.
To this end an improved master unit as well as an improved remote
unit is to be disclosed.
[0014] According to an embodiment, a master unit is provided, which
has at least one master modem, a master uplink interface, a master
downlink interface, a master downlink combiner, a master uplink
splitter, a reference frequency generator and a master transmission
unit, wherein the master modem is set up for communication with the
at least one digital network and is connected to the reference
frequency generator, wherein the master downlink interface and the
master uplink interface are set up for communication with a base
station of the at least one wireless communication network, wherein
the master downlink combiner and the master uplink splitter are set
up for connection to at least one remote unit, wherein in the
downlink direction signal lines from the master downlink combiner
are combined to form a common signal line, to which the reference
frequency signal of the reference frequency generator and a data
signal of the master modem are connected, and the common signal
line is guided in the master transmission unit, wherein in the
uplink direction from a common signal line in the master uplink
splitter signal lines are split and a data signal of the master
modem is coupled out, wherein the reference frequency signal of the
reference frequency generator is used for modem clocking.
[0015] The remote unit provided for this purpose according to an
embodiment of the invention comprises at least one remote modem, a
remote uplink interface, a remote downlink interface, a remote
uplink combiner, a remote downlink splitter, a reference frequency
receiver and a remote transmission unit, wherein the remote modem
is set up for communication with at least one user terminal and is
connected to the reference frequency receiver, wherein the remote
downlink interface and the remote uplink interface are set up for
communication with a network terminal of the at least one wireless
communication network, wherein the remote downlink splitter and the
remote uplink combiner are set up for connection to a master unit,
wherein in the downlink direction a common signal line is guided
from the remote transmission unit, to which a reference frequency
signal and a data signal of the at least one digital network are
uncoupled and fed to the reference signal receiver or the remote
modem, and the common signal line in the remote downlink splitter
is divided among a number of signal lines, which are connected to
the remote downlink interface, and wherein in the uplink direction
a number of signal lines are combined in the remote uplink combiner
to form a common signal line, to which the data signal of the
remote modem is connected, and this common signal line in the
uplink direction is connected to the remote transmission unit.
[0016] The multiband transmission system according to an embodiment
of the invention for distributing and combining signals of at least
one wireless communication network and of at least one digital
network comprises at least one above-mentioned master unit and at
least one above-mentioned remote unit, wherein the remote uplink
interface and the remote downlink interface of the at least one
remote unit are connected to the master downlink interface and the
master uplink interface of the at least one master unit via a
central signal line. In particular for connection to the master
unit, several master uplink and master downlink interfaces and on
the remote unit several remote downlink and remote uplink
interfaces can be provided.
[0017] The invention is now based on the idea of guiding as
cost-effectively and simply as possible signals of at least one
wireless communication network (GSM, DCS, UMTS, LTE, AWS, PCS,
WiMAX, etc.) and signals of at least one digital network (computer
network, Ethernet, digital audio signals or video signals, DVB,
etc.) jointly between a master unit and a remote unit via a signal
line. To this end in the master unit a reference frequency
generator is centrally provided, the frequency of which in
particular is used to generate the carrier frequency for
transmission of the digital signals. To this end the reference
frequency generator in the master unit is connected to the master
modem, in which the corresponding modulation/demodulation take
place. On the remote side a reference frequency receiver is
provided, to which the uncoupled reference frequency signal
concomitantly transmitted in the downlink direction is fed. The
reference frequency receiver restores the reference frequency. With
this reference frequency a remote modem located in the remote unit
is actuated or clocked for the modulation/demodulation of the
transmitted or received signals of the digital network.
[0018] As a carrier frequency for the transmission of the signals
of the digital network, a frequency is and can be used which is
sufficiently spaced apart from the frequency bands of the standards
for the transmission of signals within wireless communication
networks so that intermodulation effects do not occur, even taking
sidebands into consideration. This renders possible in particular
the transmission of the signals of the wireless communication
networks at the same frequency. It is further utilized thereby that
the frequency bands of the standards for the transmission of
wireless communication also have a sufficient signal to noise ratio
with respect to one another.
[0019] With the arrangement according to the invention, in
particular a point to multiple point arrangement can be realized,
wherein a master unit is connected to several remote units via a
respective common signal line. At each of these remote units a
signal of the digital network can be fed in as well as picked off.
Likewise, at each of these remote units via a mobile terminal a
bi-directional communication can be set up within one of the
transmitted wireless communication networks.
[0020] The reference frequency signal concomitantly transmitted via
the common signal line represents a clocking for a clean scan of
the transmitted digital information. Because the remote unit has a
remote modem, for example a user can log in at the remote unit and
program the master unit for example via the Ethernet or another
digital network. The master unit itself has a master modem, which
is the interface with the digital network there. In other words,
the digital data or the network as such is as it were "looped
through" by the master unit to the remote unit or to several remote
units. In this respect, the end user can access via the remote unit
the devices connected in the network of the master unit. At the
same time all remote units are synchronized via the concomitantly
transmitted reference frequency signal; they all clock identically.
In particular a service channel to the master unit can also be set
up via the digital network carried along.
[0021] The master downlink interface and the master uplink
interface are used for communication of the master unit with the
base station in the downlink direction or in the uplink direction.
Accordingly, the remote downlink interface and the remote uplink
interface are provided for communication between the remote unit
and the terminal in the downlink direction or in the uplink
direction. The master downlink combiner combines the individual
signal lines of the master unit to the common signal line.
Accordingly, the master uplink splitter splits the common signal
line into individual signal lines. Conversely, the remote downlink
splitter splits the common signal line, while the remote uplink
combiner combines the individual signal lines to a common signal
line.
[0022] The master modem is provided in order to take the data
signal of the digital network from the common signal line in the
master unit in the uplink direction, which master modem uses the
reference signal for clocking. For modulation/demodulation in the
downlink direction and in the uplink direction, in particular
separate modems can also be used. Likewise, in the remote unit for
modulation/demodulation in the downlink direction and in the uplink
direction, separate remote modems can be used, which are
respectively connected to the reference frequency receiver for
clocking.
[0023] In an embodiment of the master unit, the reference frequency
generator is embodied to generate a reference frequency signal of
low signal strength with a sufficient signal to noise ratio, taking
into consideration harmonics and intermodulation products, from the
other frequency bands of the transmission signals. It is thus
ensured that the concomitantly transmitted reference frequency
signal itself does not contribute to intermodulation effects. Even
with a low signal strength, on the remote side the reference
frequency signal can be easily restored or detected due to its
simple and specific characteristics. The reference frequency signal
in the simplest variant is transmitted as a sine signal.
[0024] In a further embodiment, a spread sequence generator is
connected downstream of the reference frequency generator in the
master unit, which spread sequence generator is used to spread the
data signal of the master modem. In other words, the reference
frequency generator is used for clocking the spread sequence
generator. The spread sequence generator generates a spread
sequence or a spread code. By means of the spread sequence of the
spread code the data signal of the master modem is spread, whereby
the bandwidth of the data signal is characteristically enlarged.
The original signal can easily be removed again from a noise
background from the spread signal, even with relatively low
intensity.
[0025] In a further embodiment, the spread sequence generator is
used to spread the reference frequency signal itself. The reference
frequency signal is thus transmitted with the same advantages as
have just been described for the data signal. In particular the
intensity of the reference frequency signal can be further reduced
again. The reference frequency signal can easily be regenerated
from a background noise.
[0026] The master modem or the remote modem can be used for any
desired modulation of the carrier frequency or demodulation from
the carrier frequency. However, the master modem and the remote
modem are particularly preferably embodied for a QAM or an FSK
modulation/demodulation. In the QAM modulation, the digital data
are modulated onto two phase-shifted signals of the same carrier
frequency. The phase-shifted signals are subsequently added.
Digital data with high quality can be transmitted via a carrier
frequency via quadrature amplitude modulation (QAM). Depending on
the number of the coded conditions, this is also referred to as a 4
(2 bit), 8 (3 bit), 16 (4 bit) or in general a multi-QAM
modulation. For demodulation, the carrier signal is necessary in
the same phase according to the modulation. This takes place in
this case via the transmission of the reference frequency signal
over the same signal line. With FSK modulation (frequency shift
keying), different frequencies are assigned to given digital
signals or bit sequences. The carrier frequency is modulated
accordingly. In the simplest case, the modulation takes place with
two different frequencies. In the case of several frequencies, this
is referred to as a multi-FSK modulation.
[0027] Also, the signals of different standards of the mobile
communication networks can be transmitted at the same frequency. In
a particularly advantageous embodiment, the master unit comprises a
frequency mixer connected to the reference frequency generator,
which frequency mixer in the uplink direction is assigned to a
number of the signal lines from the master uplink splitter and in
the downlink direction is assigned to a number of the signal lines
in the master downlink combiner, wherein the frequency mixer is set
up in the downlink direction to convert a number of overlapping
frequency bands of the transmission signals into free intermediate
frequency bands and in the uplink direction to again convert a
number of converted intermediate frequency bands.
[0028] Accordingly, in the remote unit, a frequency mixer connected
to the reference frequency receiver is comprised, which in the
downlink direction is assigned to a number of the signal lines from
the master downlink splitter and in the uplink direction is
assigned to a number of the signal lines in the master uplink
combiner, and wherein the frequency mixer is set up in the uplink
direction to convert a number of overlapping frequency bands of the
transmission signals into free intermediate frequency bands and in
the downlink direction to convert again a number of converted
intermediate frequency bands.
[0029] A frequency mixer or frequency divider of this type can be
accomplished, for example, via a frequency generator or
synthesizer, which is clocked via the reference frequency signal.
In the master unit the reference frequency signal is taken from the
reference frequency generator. In the remote unit the reference
frequency signal is obtained by means of the reference frequency
signal receiver. By frequency mixing, the frequency of the desired
signal is then converted into a suitable different frequency. In
the master unit in the uplink direction the frequency-converted
signals received by the remote unit are then converted again. This
likewise occurs in the downlink direction in the remote unit. The
frequency of the converted signals does not necessarily need to be
thereby converted to the original frequency again. It is also
possible to convert the converted signals into a different
frequency band. In this manner, for example, a transmission
standard can be shifted into a different communication band.
[0030] For the frequency conversion and frequency reversal in the
uplink or downlink direction, in particular separate frequency
mixers can be used. These are respectively synchronized by the
reference signal.
[0031] A frequency conversion as described above is advisable in
particular when two separate signals are transmitted within
frequency bands that overlap or in which at least the danger of an
intermodulation exists. In order to avoid such an intermodulation
in a signal transmitted by means of Frequency Division Duplexing,
it is provided to convert overlapping frequency bands of the
transmission signals into free intermediate frequency bands. It is
assumed thereby that such free intermediate bands with sufficiently
large width or distance are provided between the frequency bands of
the standards for the transmission of wireless information for
avoiding overlapping effects. The hitherto free intermediate bands
of the overlapping frequency bands for the transmission of signals
are used by the described approach. In other words, overlapping
frequency bands of different signals are distributed among the free
intermediate bands so that overall a clear reduction of
intermodulation effects, etc. occurs. Preferably, with a number n
of overlapping frequency bands only a number of n-1 can thereby be
converted into free intermediate frequency bands, while one of
these signals is carried out on its frequency without conversion.
The intermodulation problem is hereby avoided with low expenditure
to the same extent.
[0032] The above-mentioned situation applies in particular when
same-frequency signals of different information content, in
particular so-called MIMO signals, are to be transmitted. Such
signals, which come for different sectors, for example, or, as in
the case of MIMO, are received via spatially separated antennas,
are transmitted within the same frequency band, but fundamentally
are to be separated from one another on the receiver side.
[0033] In a particularly advantageous embodiment, in the master
unit the frequency mixer or frequency mixers for frequency
conversion and frequency restoration of the same-frequency signals
is thus assigned to the signal lines of the same-frequency signals,
wherein the other frequency bands are carried out on their
frequency without conversion.
[0034] Accordingly, in the remote unit the frequency mixer for
frequency conversion and frequency restoration of the
same-frequency signals is assigned to the signal lines of the
same-frequency signals, wherein the other frequency bands are
carried out without conversion at the same frequency.
[0035] Through this embodiment it is achieved that the
same-frequency signals, in particular MIMO signals, for
transmission via the common signal line between the master unit and
the remote unit are converted separately from one another into free
intermediate frequency bands. Thus no modulation effects occur
during the transmission. The same-frequency signals in particular
can be separated again from the signals of the same standard and
from one another even after the transmission via the common signal
line. As already described, respectively the reference frequency
signal concomitantly transmitted or generated in the master unit is
used to this end both for frequency mixing as well as also for
frequency division.
[0036] Advantageously, further the master modem is embodied for the
transmission of digital baseband data on the common signal line.
Accordingly, preferably in the remote unit the remote modem is
likewise embodied for the transmission of digital baseband data on
the common signal line. The data are thereby transmitted with the
same frequency that they have as a time signal. An example of this
is the Ethernet. The digital data contained therein are transmitted
by means of a time multiplex method. The assignment to individual
devices or addresses is hereby carried out via a channel
coding.
[0037] In order to ensure with a point-to-multiple point connection
that the remote units transmit simultaneously, so that all of the
devices connected or linked thereto are synchronized, a number of
adjustable delay elements for delaying the transmission signals are
comprised by the remote unit or each remote unit. The transmission
links of different lengths between the master unit and the
different remote units can thus be taken into account.
[0038] In a preferred embodiment of the multiband transmission
system realized by means of master unit and remote unit, the
central signal line is an optical wave guide, wherein an
optoelectrical converter unit for the respective conversion of the
transmission signals between their electrical and optical
modification is respectively assigned to the remote unit and the
master unit
[0039] Further scope of applicability of the present invention will
become apparent from the detailed description given hereinafter.
However, it should be understood that the detailed description and
specific examples, while indicating preferred embodiments of the
invention, are given by way of illustration only, since various
changes and modifications within the spirit and scope of the
invention will become apparent to those skilled in the art from
this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] The present invention will become more fully understood from
the detailed description given hereinbelow and the accompanying
drawings which are given by way of illustration only, and thus, are
not limitive of the present invention, and wherein:
[0041] FIG. 1 illustrates diagrammatically the transmission path
between a master unit and a remote unit in downlink direction;
and
[0042] FIG. 2 illustrates diagrammatically the structure of a
master unit.
DETAILED DESCRIPTION
[0043] FIG. 1 shows diagrammatically the common transmission of
signals of two digital networks and of signals of three wireless
communication networks between a master unit 2, 2' and a remote
unit 3, 3'. The master unit 2, 2' and the remote unit 3, 3'
together form a multiband transmission system 1 for distributing
and combining signals of at least one wireless communication
network and of at least one digital network. The downlink region is
hereby labeled by 2, 3, while the uplink region is given by 2' and
3'.
[0044] The master unit 2, 2' hereby comprises signal lines a, b or
a', b' for transmitting or exchanging signals within respectively
one digital network. The digital data before transmission by means
of a first master modem 5 and by means of a second master modem 6
are hereby modulated on a carrier frequency. Both master modems 5,
6 are hereby embodied for a multi QAM modulation. In the uplink
direction the further master modems 5' and 6' are provided for the
demodulation of the corresponding modulated digital signals coming
from the remote unit 3, 3'.
[0045] Furthermore, the master unit 2, 2' comprises three signal
lines c, d and e or c', d' and e', which are connected via radio or
cable to the base station BTS of a wireless communication network.
The three signal lines c, d and e or c', d' and e' are thereby
respectively assigned to signals of different mobile radio
standards. In particular this can be LTE, UMTS, DCS or GSM.
[0046] The signal lines a through e or a' through e' are part of a
master downlink interface 9 or part of a master uplink interface 8.
The coupling of the master unit 2, 2' to the base station BTS and
to the two digital networks takes place via these interfaces 8 and
9. Likewise, the master downlink interface 9 and the master uplink
interface 8 are set up for communication with the remote unit 3,
3'.
[0047] The master unit 2, 2' has further a reference frequency
generator 12, for example, a vibrating quartz crystal, which on the
output side generates a reference frequency signal used for
clocking. The output line of the reference frequency generator 12
is labeled by f.
[0048] The reference frequency signal of the reference frequency
generator 12 is branched off for the two master modems 5, 6 or 5',
6' from the signal line f. It can thereby be provided in particular
to convert the reference frequency signal itself, for example, via
a multiplication or a division into a different carrier frequency
of the master modem 5, 6 or 5', 6'.
[0049] A first frequency generator 15 and 15' or a second frequency
generator 16 and 16' is respectively assigned to the signal lines d
and e as well as d' and e', which on the output side are assigned
via a first frequency mixer 17 and 17' or a second frequency mixer
18 and 18' to the signal lines d and e as well as d' and e'. The
frequencies of the signals propagated in the signal lines d and e
in the downlink direction are frequency converted by means of the
frequency mixer 17, 18, in particular into free intermediate bands
between the individual transmission standards. In particular the
signals in the signal lines d and e can be so-called MIMO signals
within a standard, which come from spatially separated antennas.
The two MIMO signals are converted in the master unit 2, 2' into
free intermediate bands, so that an intermodulation with other
signals is avoided and the two MIMO signals on the remote side can
be easily separated from one another again. In order to separate
the desired frequency band during frequency mixing, in the signal
lines d and e a first or a second bypass filter 19, 20 is connected
downstream of the frequency mixers 17 or 18. Conversely, the
signals of this signal line converted into free intermediate bands
are again converted to the original frequency with the two
frequency mixers 17' and 18' by frequency mixing in the uplink
direction.
[0050] The QAM modulated signals of the two digital data channels a
and b, the reference frequency signal in the signal line f, the
same-frequency signal of the signal line c as well as the frequency
converted signals of the signal lines d and e are combined in the
master downlink combiner 10 into a common signal line 23. In the
downlink direction DL the signals of the common signal line 23 are
further converted into optical signals in a master transmission
unit 25 via an optoelectrical converter unit 25 and fed via an
optical wave guide 27 to the remote unit 3.
[0051] The remote unit 3, 3' comprises a remote downlink interface
33 as well as a remote uplink interface 32, which basically are
used for the connection to an end user USER. Both of the interfaces
33 and 32 of the remote unit 3, 3' open via the signal lines 34,
34' into a common remote transmission unit 36, into which the
optical cable 27 of the master unit 2, 2' is guided.
[0052] In the remote transmission unit 36 the received signals and
the signals to be transmitted of the optical wave guide 27 are
converted into electrical or into optical signals. These run or
come via the signal line 34 or 34' into a remote downlink splitter
30 or a remote uplink combiner 31, in which they are separated from
one another, for example, by means of suitable filters and are
distributed in corresponding assignment according among the master
unit 2 or 2' to the signal lines a-e or a'-e' of the remote unit 3
or 3'.
[0053] The concomitantly transmitted reference frequency signal of
the reference frequency generator 12 (in the master unit 2) is
taken from the signal line f or restored from the transmission
frequency (for example, spread band coded). This takes place by
means of a reference frequency receiver 40 and a downstream
frequency generator 42 operating in slave operation. The restored
actual reference frequency is fed via the signal line f to a first
remote modem 38, 38' and a second remote modem 39, 39'. The
respective QAM modulated signals are demodulated or modulated there
by means of the reference frequency. Accordingly, in the downlink
direction the signals of the two digital networks are again present
in the signal lines a and b.
[0054] The same-frequency signal can be taken from signal line c as
provided on the side of the master unit 2.
[0055] The same-frequency signal in the uplink direction can be fed
for transmission to the master unit 2, 2' into the signal line
c'.
[0056] The downlink signals converted into side bands are taken
from the signal lines d and e via a first and a second band pass
filter 52, 53. The signals are returned to the original frequency
of the transmission standard via the frequency generators 47, 48
containing the restored reference frequency and embodied as
synthesizers as well as frequency dividers 49, 50 connected
thereto.
[0057] In the uplink direction the input signals on the signal
lines d' and e' with the aid of the frequency converters 50' and
49' are converted to non-overlapping frequency bands. After
filtering through the band pass filters 52' and 53', the signals d'
and e' are combined with the same-frequency signal c' as well as
the uplink signals of the remote modems 38' and 39'.
[0058] The end user can exchange digital data via the two signal
lines a and b or a' and b'. For example, he can address via the
Ethernet individual devices on the side of the master unit 2, 2'.
In particular an addressing of the master unit 2 or 2' itself is
possible, so that the programming thereof is possible via an access
to the remote unit 3, 3'.
[0059] The signal lines c, d and e or c', d' and e' are connected
to corresponding antennas for wireless communication. The end user
can communicate bi-directionally with a mobile terminal.
[0060] FIG. 2 shows diagrammatically the arrangement of individual
components of a master unit 2, 2', which corresponds approximately
to the master unit shown in FIG. 1. The orientation of the master
unit 2, 2' is thereby changed compared to the master unit according
to FIG. 1. In FIG. 2 the assigned base station BTS is on the right
side.
[0061] On the left side the optical wave guide 27 can be seen on
which all signals are exchanged bi-directionally with a remote unit
according to the Frequency Division Duplexing (FDD) method.
[0062] A master modem 5, 5' is provided for the transmission of
digital data or signals of a digital network. This master modem
comprises a physical interface PHY to the digital network for the
conversion of coded signals on the physical carrier medium of the
network in digital user data in the receiver direction and in the
transmission direction the conversion of digital user data into a
coded signal for the corresponding carrier medium. Via a field
programmable gate array (FPGA) and by means of a digital analog
converter (DAC) the digital user data obtained from the digital
network are modulated and combined with other signals as a
modulated frequency signal for transmission. A quadrature amplitude
modulation (QAM) is provided as modulation. On the receiver side a
modulated frequency signal is received by means of an analog
digital converter (ADC) and demodulated with corresponding receiver
logic. In this case the transmission of the digital user data is
provided according to the DVB-C standard.
[0063] For clocking the master modem 5, 5' a reference frequency
generator 12 is provided in the master unit 2, 2', which reference
frequency generator in this case is embodied as a vibrating quartz
crystal. The frequencies necessary for the modulation/demodulation
are derived herefrom via corresponding division. The reference
frequency generator 12 is used at the same time for clocking a
frequency generator 15, which in this case is embodied as a
synthesizer.
[0064] Furthermore, the master unit 2, 2' comprises a processor 60,
which controls via bus lines the leveling of the signal paths of
the wireless communication network. Furthermore, it is a function
of this processor 60 to carry out all operating adjustments and to
collect possible error or operating information. Like the
corresponding processor in the remote unit, this processor 60 is
connected via an Ethernet link to a central control and monitoring
unit.
[0065] The downlink combiner and the uplink splitter used for
combing the downlink signals or dividing the uplink signals
comprise a number of first duplexer units 65, 67 or 65', 67', which
are assigned to transmission bands of the different wireless
communication systems. The duplexer units 65, 67, 65', 67' have the
function of damping the signals in a band-specific manner for a
suitable transmission on the optical link in the downlink direction
and of amplifying them in the uplink direction.
[0066] Since the connection to the base station BTS of the
different wireless communication networks is carried out via a
combined line/antenna, the associated downlink and uplink signals
must be separated or combined in the duplexer units 62 according to
the FDD method. A first antenna A1 and a second antenna A2 for
receiving/transmitting MIMO signals, an antenna B for
receiving/transmitting UMTS signals, an antenna C for
receiving/transmitting DCS signals and an antenna D for
receiving/transmitting GSM signals are assigned to the master
uplink interface 8 or the master downlink interface 9. A connection
to a digital network can be established via the connection E. In
other words, the master unit 2, 2' is configured for a multiband
transmission system.
[0067] If the signal propagation in the downlink direction DL is
considered, the received signals of the MIMO antennas A1 and A2 by
means of the frequency mixers 17, 18, which are connected to
outlets of the frequency generator 15, are converted into free
intermediate frequency bands between the individual standards. The
other signals of the cited standards of mobile communication are
continued at the same frequency. The frequency converted MIMO
signals are connected by means of a coupling element 63.
[0068] Via the second duplexer units 65 respectively undesirable
sidebands are removed. The signals according to UMTS and according
to DCS are combined in the downlink direction DL. Likewise, the
MIMO signals and the signals according to GSM are combined in the
downlink direction.
[0069] In the third duplexer units 67 side bands are again
suppressed, or the undesirable larger or smaller frequencies are
removed. Subsequently in the downlink direction DL all the signals
of the wireless communication network services are combined.
[0070] In the downlink direction, further the common signals are
combined with the reference frequency signal of the reference
frequency generator 12 by means of the coupling element 70.
Respectively interfering larger or smaller frequencies are
suppressed via fourth duplexer units 72. In particular, the signals
of one or more digital networks are connected as data signals of
the master modem 5.
[0071] Via an optical converter unit 73 all of the electrical
frequency multiplexed signals are converted into optical signals
and fed to the optical wave guide 27. All of the signals are fed to
a connected remote unit via the optical wave guide 27.
[0072] In the uplink direction UL, the received signals initially
are converted into electrical signals by means of the
optoelectrical converter unit 73'. By means of the fourth duplexer
units 72' the signals of one or more digital networks are uncoupled
and the modulated frequency signal is fed to the master modem
5.
[0073] The other signals of the wireless communication networks are
initially distributed via the third duplexer units 67' between two
frequency bands. The further distribution among the total of four
signals of different frequency bands of the transmitted standard is
carried out via the second duplexer units 65'. The two MIMO signals
are distributed between two mixing steps by means of a splitter
63'. The MIMO signals are then restored via the frequency separator
17', 18' to the original frequency bands. All of the signals
finally run to the corresponding antennas for emission or to the
antenna connections of the BTS.
[0074] The invention being thus described, it will be obvious that
the same may be varied in many ways. Such variations are not to be
regarded as a departure from the spirit and scope of the invention,
and all such modifications as would be obvious to one skilled in
the art are to be included within the scope of the following
claims.
* * * * *