U.S. patent application number 12/621968 was filed with the patent office on 2010-05-13 for radio communication apparatus, radio communication system and radio communication method.
This patent application is currently assigned to FUJITSU LIMITED. Invention is credited to Tomohiko Choraku, Shuya Hirata, Jun Sugiyama.
Application Number | 20100118751 12/621968 |
Document ID | / |
Family ID | 40074619 |
Filed Date | 2010-05-13 |
United States Patent
Application |
20100118751 |
Kind Code |
A1 |
Sugiyama; Jun ; et
al. |
May 13, 2010 |
RADIO COMMUNICATION APPARATUS, RADIO COMMUNICATION SYSTEM AND RADIO
COMMUNICATION METHOD
Abstract
A radio communication apparatus for performing radio
communication, including: a first interface conversion unit which
extracts a first signal and a second signal multiplexed and input,
and corresponding to two different formats, and combines the
extracted first and second signal; and a common amplifier which is
shared by the first and second signal by amplifying the combined
first and second signal, wherein a signal output from the common
amplifier is transmitted.
Inventors: |
Sugiyama; Jun; (Kawasaki,
JP) ; Hirata; Shuya; (Kawasaki, JP) ; Choraku;
Tomohiko; (Kawasaki, JP) |
Correspondence
Address: |
HANIFY & KING PROFESSIONAL CORPORATION
1055 Thomas Jefferson Street, NW, Suite 400
WASHINGTON
DC
20007
US
|
Assignee: |
FUJITSU LIMITED
Kawasaki-shi
JP
|
Family ID: |
40074619 |
Appl. No.: |
12/621968 |
Filed: |
November 19, 2009 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2007/000565 |
May 25, 2007 |
|
|
|
12621968 |
|
|
|
|
Current U.S.
Class: |
370/310 ;
370/465 |
Current CPC
Class: |
H04B 1/406 20130101;
H04W 4/18 20130101; H04W 92/20 20130101; H04W 88/06 20130101 |
Class at
Publication: |
370/310 ;
370/465 |
International
Class: |
H04B 7/00 20060101
H04B007/00 |
Claims
1. A radio communication apparatus for performing radio
communication, comprising: a first interface conversion unit which
extracts a first signal and a second signal multiplexed and input,
and corresponding to two different formats, and combines the
extracted first and second signal; and a common amplifier which is
shared by the first and second signal by amplifying the combined
first and second signal, wherein a signal output from the common
amplifier is transmitted.
2. The radio communication apparatus according to claim 1, further
comprising: a second interface conversion unit which is connected
with an other radio communication apparatus that processes a first
format in the two different formats, and which input with the first
signal from the other radio communication apparatus and the second
signal corresponding to a second format in the two different
formats, multiplexes the first signal and the second signal, and
outputs, wherein a signal output from the second interface
conversion unit is input to the first interface conversion
unit.
3. The radio communication apparatus according to claim 1, wherein
the first interface conversion unit is connected with an other
radio communication apparatus that processes a first format in the
two different formats, and outputs the first signal without
combining the second signal with the first signal from the other
radio communication apparatus, and the common amplifier amplifying
and outputs only the first signal.
4. The radio communication apparatus according to claim 2, wherein
the second interface conversion unit outputs the second signal to
the other radio communication apparatus without multiplexing the
second signal with the first signal, and the first interface
conversion unit is input with the first signal and the second
signal multiplexed in the other radio communication.
5. The radio communication apparatus according to claim 1, wherein
the first interface conversion unit is directly connected with an
other radio communication apparatus which processes a first format
in the two different formats, and is also directly connected with a
third interface conversion unit which processes a second format in
the two different formats, and the first interface conversion unit
is input with the first signal and the second signal from the other
radio communication apparatus and the third interface conversion
unit, respectively, without the first and second signal being
multiplexed, combines the first signal and the second signal, and
outputs to the common amplifier.
6. The radio communication apparatus according to claim 2, wherein
the second interface conversion unit frequency-converts the first
and second signal on a time axis to the first and second signal on
a frequency axis, combines the frequency-converted first and second
signal by adding the frequency-converted first and second signal on
the frequency axis, again converts the combined first and second
signal to signal on the time axis, and outputs the first and second
signal converted to signal on the time axis.
7. A radio communication system, comprising: a first radio
communication apparatus; and a second radio communication
apparatus, wherein the first radio communication apparatus includes
a first interface conversion unit which processes a first signal
corresponding to a first format, and the second radio communication
apparatus includes: a second interface conversion unit which is
directly connected with the first interface conversion unit, and
which is input with the first signal from the first interface
conversion unit and a second signal corresponding to a second
format, multiplexes the first signal and the second signal, and
outputs; a third interface conversion unit which is input with
multiplexed signal from the second interface conversion unit,
extracts the first and second signal, and combines the extracted
first and second signal; and a common amplifier which amplifies the
first and second signals combined by the third interface conversion
unit.
8. The radio communication system according to claim 7, wherein the
second interface conversion unit outputs the second signal to the
first interface conversion unit without multiplexing the second
signal with the first signal, the second interface conversion unit
multiplexes the second signal and the first signal, and the third
interface conversion unit is directly connected with the second
interface conversion unit, and is input with the multiplexed first
and second signal.
9. A radio communication method in a radio communication apparatus
for performing radio communication, the method comprising:
extracting multiplexed input first and second signal corresponding
to two different formats respectively; combining the extracted
first and second signal; amplifying the combined first and second
signal with a common amplifier; and transmitting signal output from
the common amplifier.
10. A radio communication method in a radio communication system
including a first radio communication apparatus and a second radio
communication apparatus, the method comprising: inputting a first
signal corresponding to a first format from the first radio
communication apparatus and multiplexing the first signal with a
second signal corresponding to a second format in the second radio
communication system; combining the extracted first and second
signal; and transmitting the combined first and second signal after
amplifying the signal with a common amplifier of the second radio
communication system.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of International
Application No. PCT/JP2007/000565, filed on May 25, 2007, now
pending, herein incorporated by reference.
TECHNICAL FIELD
[0002] The present invention relates to a radio communication
apparatus, a radio communication system and a radio communication
method.
BACKGROUND ART
[0003] In the field of radio communications, communication systems
using new communication formats are being constructed and radio
services are being provided accompanying advances in technology. At
that time, since normally numerous users do not switch to a new
radio service immediately, but rather switch gradually, multiple
radio services are implemented in parallel. In addition, when
constructing new communication formats, although this involves the
introduction of new, dedicated equipment to accommodate those
formats, since existing services are still being implemented, it is
necessary to secure locations for installing the dedicated
equipment that is compatible with the new communication format.
[0004] FIG. 10 is a drawing depicting an example of the
configuration of a radio base station (BTS) 200 of the prior art
(see, for example, Non-Patent Document 1). The radio base station
200 is provided with a radio equipment (RE) 220 which performs out
processing on radio signals such as filtering, modulation and
frequency conversion, and a radio equipment controller (REC) 210
which performs processing on baseband signals. The radio equipment
220 and the radio equipment controller 210 are connected by an
optic fiber in the form of an optical communication cable, and an
interface in the form of a common public radio interface (CPRI) is
interposed there between.
[0005] In addition, the following Patent Document 1 indicates an
example of the prior art that uses this type of CPRI for the
interface.
[0006] Non-Patent Document 1: CPRI Specification V2.1
[0007] Patent Document 1: Japanese Patent Application No.
2007-999656
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0008] In order to allow a radio base station to switch to a new
radio service, it is desirable that the radio base station be able
to share both old and new services to enable it to be compatible
both services.
[0009] In addition, it is possible to consider installing two radio
base stations in parallel as depicted in FIG. 10 in order to
provide radio base stations capable of being compatible with two
old and new services (or two different services).
[0010] However, it is necessary to install an optical cable for
connecting the radio equipment and the radio equipment controller
in order to additionally provide the radio base station. However,
installing the additional optical cable leads to increased costs.
Thus, it would be desirable to be able to integrate and transmit
two services using an existing optical cable.
[0011] Moreover, a radio base station compatible with multiple
services would also be desirable.
[0012] Therefore, with the foregoing in view, it is an object of
the present invention to provide a radio communication apparatus
capable of sharing two radio services so as to be able to be
compatible with both services, a radio communication system, and a
radio communication method.
[0013] In addition, it is another object of the present invention
to provide a radio communication apparatus and the like capable of
providing two services without increasing the number of optical
cables.
[0014] Moreover, it is another object of the present invention is
to provide a radio communication apparatus and the like that is
compatible with multiple services.
Means for Solving the Problem
[0015] A radio communication apparatus for performing radio
communication, including: a first interface conversion unit which
extracts a first signal and a second signal multiplexed and input,
and corresponding to two different formats, and combines the
extracted first and second signal; and a common amplifier which is
shared by the first and second signal by amplifying the combined
first and second signal, wherein a signal output from the common
amplifier is transmitted.
[0016] A radio communication system, including: a first radio
communication apparatus; and a second radio communication
apparatus, wherein the first radio communication apparatus includes
a first interface conversion unit which processes a first signal
corresponding to a first format, and the second radio communication
apparatus includes: a second interface conversion unit which is
directly connected with the first interface conversion unit, and
which is input with the first signal from the first interface
conversion unit and a second signal corresponding to a second
format, multiplexes the first signal and the second signal, and
outputs; a third interface conversion unit which is input with
multiplexed signal from the second interface conversion unit,
extracts the first and second signal, and combines the extracted
first and second signal; and a common amplifier which amplifies the
first and second signals combined by the third interface conversion
unit.
[0017] A radio communication method in a radio communication
apparatus for performing radio communication, the method including:
extracting multiplexed input first and second signal corresponding
to two different formats respectively; combining the extracted
first and second signal; amplifying the combined first and second
signal with a common amplifier; and transmitting signal output from
the common amplifier.
ADVANTAGEOUS EFFECT OF THE INVENTION
[0018] According to the present invention, a radio communication
apparatus, a radio communication system and a radio communication
method can be provided that enable two services to be accommodated
smoothly. In addition, a radio communication apparatus and the like
can be provided that is able to provide two services without
increasing the number of optical cables. Moreover, a radio
communication apparatus and the like can be provided that is
compatible with multiple services.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a drawing depicting an example of the
configuration of a radio communication system;
[0020] FIG. 2 is a drawing depicting an example of the
configuration of a radio base station;
[0021] FIG. 3 is a drawing depicting an example of a transmission
frame of a CPRI;
[0022] FIGS. 4(A) through 4(C) are drawings depicting examples of
transmission frames of a CPRI;
[0023] FIG. 5 is a drawing depicting another example of the
configuration of a radio communication system;
[0024] FIG. 6 is a drawing depicting another example of the
configuration of a radio base station;
[0025] FIGS. 7(A) through 7(C) are drawings depicting examples of
transmission frames of a CPRI;
[0026] FIG. 8 is a drawing depicting another example of the
configuration of a radio base station;
[0027] FIG. 9 is a drawing depicting another example of the
configuration of a radio base station; and
[0028] FIG. 10 is a drawing depicting an example of the
configuration of a radio base station of the prior art.
EXPLANATION OF REFERENCE NUMERALS
[0029] 1, 3 first, second host apparatus [0030] 2, 4 first, second
radio base station [0031] 21, 41, 44 first, second, third radio
equipment controller (REC) [0032] 42, 43, 44 second, third, fourth
radio equipment (RE) [0033] 213, 413, 421, 431, 441 first, second,
third, fourth, fifth interface conversion unit [0034] 422 reception
amplification unit [0035] 2131, 4131, 4134, 4137, 4312, 4314, 4415,
4218 first, second, third, fourth, fifth, sixth, seventh, eighth
CPRI processing unit [0036] 2132, 4132, 4133, 4136, 4138, 4211,
4311, 4313, 4416 first, second, third, fourth, fifth, sixth,
seventh, eighth, ninth conversion unit [0037] 4135, 4212 first,
second service multiplex separation unit [0038] 4213 frequency
shift unit [0039] 4214 IQ extraction unit [0040] 4222 modulation
unit [0041] 4225 down converter [0042] 4411, 4413, 4417 first,
second, third time-frequency conversion unit [0043] 4414, 4419,
4420 first, second, third frequency-time conversion unit
BEST MODE FOR CARRYING OUT THE INVENTION
[0044] The following provides an explanation of embodiments of the
present invention.
First Embodiment
[0045] First, an explanation is provided of a first embodiment.
FIG. 1 is a drawing depicting an example of the configuration of a
radio communication system 100. The radio communication system 100
includes a host apparatus 1 (to be referred to as a first host
apparatus) which corresponds to a radio service A, a radio base
station 2 (to be referred to as a first radio base station), a host
apparatus 3 (to be referred to as a second host apparatus) which
corresponds to a radio service B, a radio base station 4 (to be
referred to as a second radio base station), and an antenna 5.
[0046] In addition, the first radio base station 2 includes a first
radio equipment controller (REC) 21. The first radio equipment
controller 21 includes a first common control unit 211, a first
baseband signal processing unit 212, and a first interface
conversion unit 213.
[0047] On the other hand, the second radio base station 4 includes
a second radio equipment controller (REC) 41 and a second radio
equipment (RE) 42. The second radio equipment controller 41
includes a second common control unit 411, a second baseband signal
processing unit 412, and a second interface conversion unit 413. In
addition, the second radio equipment 42 includes a third interface
conversion unit 421 and a transmission and reception amplification
unit 422.
[0048] The two host apparatuses 1 and 3 are, for example, radio
network controllers (RNC) or access gateways (aGW), and transmit
and receive data corresponding to each of two radio services
(communication formats). Furthermore, in the embodiments indicated
to follow, the radio service A is explained as an old service,
while the radio service B is explained as a new service. Namely, in
the case the radio base station 2 corresponding to the radio
service A provides the radio service A via radio equipment not
depicted and the antenna 5, an explanation is provided for the case
in which radio services A and B are subsequently provided via the
antenna 5 by installing the radio equipment controller 41 and the
radio equipment 42 that are compatible with the radio service B in
order to provide the new service. Furthermore, at that time, the
connection line between the interface conversion unit 213 and radio
equipment not depicted is used as a line for connecting the
interface conversion unit 213 and the interface conversion unit 421
of the radio equipment 42, after which this line is reconnected as
a line for connecting the interface conversion units 413 and 421,
while a connection line that connects the interface conversion
units 213 and 413 is newly added.
[0049] The first and second radio equipment controllers 211 and 411
control the radio base stations 2 and 4 by, for example,
distributing synchronizing signals to each of the radio base
stations 2 and 4, set individual settings and so forth.
[0050] The first and second baseband signal processing units 212
and 412 convert data from the host apparatuses 1 and 3 to baseband
signals composed of I (in-phase) signals and Q (quadrature phase)
signals, outputs them to the first interface conversion unit 213,
and so forth.
[0051] The first through third interface conversion units 213, 413
and 421 convert to a signal format corresponding to the connection
cables (such as CPRI), convert to baseband signals and so forth.
The details of which are described later.
[0052] Although operation of the radio communication system 100
depicted in FIG. 1 will be described later, the effects thereof are
described as follows. Namely, the second interface conversion unit
413 of the second radio equipment controller 41 multiplexes (or
combines) two signals, consisting of signals corresponding to the
radio service A from the first interface conversion unit 213 and
signals corresponding to the radio service B from the second
baseband signal processing unit 412, and outputs multiplexed
signals, as an single signal, to the second radio equipment 42. In
addition, the second interface conversion unit 413 separates
signals from the third interface conversion unit 421 into two
signals consisting of signal corresponding to the radio service A
and signal corresponding to the radio service B, and outputs the
signals to the first interface conversion unit 213 and the second
baseband signal processing unit 412, respectively. Thus, the first
radio base station 2 is not required to be installed the internal
radio equipment (RE), and it is not necessary to additionally
install an optical cable within the first radio equipment
controller 21.
[0053] FIG. 2 is a drawing depicting an example of the detailed
configuration of the first interface conversion unit 213, the
second interface conversion unit 413, the third interface
conversion unit 421, and the transmission and reception amplifier
422.
[0054] The first interface conversion unit 213 includes a first
CPRI processing unit 2131 and a first conversion unit 2132.
[0055] In addition, the second interface conversion unit 413
includes a second CPRI processing unit 4131, a second conversion
unit 4132, a third conversion unit 4133, a third CPRI processing
unit 4134, a first service multiplex separation unit 4135, a fourth
conversion unit 4136, a fourth CPRI processing unit 4137, and a
fifth conversion unit 4138.
[0056] Moreover, the third interface conversion unit 421 includes a
sixth conversion unit 4211, a second service multiplex separation
unit 4212, a frequency shift unit 4213, and an IQ extraction unit
4214.
[0057] Moreover, the transmission and reception amplifier 422
includes a D/A conversion unit 4221, a modulation unit 4222, a
transmission amplification unit 4223, a reception unit 4224, a down
converter 4225, and an A/D conversion unit 4226.
[0058] The following provides an explanation of the operation of
the radio base stations 2 and 4, containing the first through third
interface units 213, 413 and 421, with reference to FIG. 1.
[0059] First, an explanation of the operation is provided while
moving downlink (from the host apparatuses 1 and 3 towards the
antenna 5). As depicted in FIG. 1, the first host apparatus 1
outputs data corresponding to the radio service A. This data is
converted to baseband signal including the I signal and Q signal by
the baseband signal processing unit 212 via the common control unit
211. The converted baseband signal is input to the first CPRI
processing unit 2131 depicted in FIG. 2.
[0060] The first CPRI processing unit 2131 converts the baseband
signal to signal of the CPRI format (to be referred to as CPRI
signal). FIG. 3 depicts an example of a CPRI format, and the I
signal and Q signal which are baseband signal are inserted into a
data block region. The first conversion unit 2132 converts the CPRI
signal to optical signal and transmits the optical signal to the
second radio base station 4 via an optical cable.
[0061] The fourth conversion unit 4136 of the second interface
conversion unit 413 converts optical signal from the first
conversion unit 2132 to CPRI signal which is electrical signal and
outputs CPRI signal. The fourth CPRI processing unit 4137 extracts
I signal and Q signal on the basis of the CPRI signal from the
fourth conversion unit 4136 and outputs them to the first service
multiplex separation unit 4135.
[0062] On the other hand, data corresponding to the radio service B
is output from the second host apparatus 3 depicted in FIG. 1, and
the baseband signal corresponding to the radio service B is output
via the second common control unit 411 and the second baseband
signal processing unit 412. The baseband signal is then input to
the second CPRI processing unit 4131 depicted in FIG. 2
[0063] The second CPRI processing unit 4131 converts the baseband
signal to CPRI signal (see, for example, FIG. 3) and outputs CPRI
signal. The second conversion unit 4132 converts the converted CPRI
signal to optical signal. The third conversion unit 4133 converts
the converted optical signal so as to return them to CPRI signal,
and the third CPRI processing unit 4134 extracts I signal and Q
signal from the CPRI signal and outputs them to the first service
multiplex separation unit 4135.
[0064] Here, the reason for CPRI signal being converted to optical
signal by the second conversion unit 4132 is as follows. Namely, as
indicated by the broken line in FIG. 2, the second conversion unit
4132 and the sixth conversion unit 4211 of the second radio
equipment 42 can be connected by a cable such as an optical cable.
As a result of this connection, the connection between the fifth
conversion unit 4138 and the sixth conversion unit 4211 is severed,
enabling only service corresponding to the radio service B to be
provided. In other words, this connection is effective in cases in
which a shared service is not to be provided. In order to realize
this connection, for example, the second interface conversion unit
413 is configured so as to be able to be separated by providing the
second CPRI processing unit 4131 and the second conversion unit
4132 on one board, while providing the third conversion unit 4133
to the fifth conversion unit 4138 on another board as indicated
with the dotted lines. Furthermore, 4131 to 4133 can be omitted,
and the input to 4131 can also be imparted to the CPRI processing
unit 4134.
[0065] The first service multiplex separation unit 4135 multiplexes
(or combines) I signal and Q signal in the form of baseband signal
from the third CPRI processing unit 4134 and baseband signal
corresponding to service A from the fourth CPRI processing unit
4137.
[0066] FIGS. 4(A) through 4(C) are drawings depicting examples of
multiplexing processing. FIG. 4(A) depicts an example of CPRI
signal into which is inserted I signal and Q signal of service A as
an example of signals output from the fourth conversion unit 4136.
In addition, FIG. 4(B) is an example of CPRI signal into which is
inserted I signal and Q signal of service B as an example of signal
output from the second CPRI processing unit 4131 or the third
conversion unit 4133. The first service multiplex separation unit
4135 multiplexes by inserting I signal and Q signal of services A
and B extracted with the third and fourth CPRI processing units
4134 and 4137 into their respective predetermined data block region
(see FIG. 4(C)).
[0067] Returning to FIG. 2, the fifth conversion unit 4138 converts
the multiplexed CPRI signal from the first service multiplex
separation unit 4135 to optical signal. The converted optical
signal is output to the third interface conversion unit 421 of the
second radio equipment 42 via an optical cable.
[0068] The sixth conversion unit 4211 of the third interface
conversion unit 421 converts the optical signal to CPRI signal of
electric signal format. The second service multiplex separation
unit 4212 extracts baseband signal of I signal and Q signal on the
basis of the converted CPRI signal. As depicted in FIG. 4(C), since
the CPRI signal is multiplexed, I signal and Q signal corresponding
to service A and I signal and Q signal corresponding to service B
are extracted, and the extracted I signals and Q signals of each
service are output to the frequency shift unit 4213.
[0069] The frequency shift unit 4213 shifts the frequency of the
respective I signals and Q signals corresponding to each service to
a predetermined frequency band. At that time, the frequency bands
are prevented from overlapping between services A and B. The
digitally represented waveform signal for which frequency is
shifted is output to the transmission and reception amplifier 422.
Furthermore, signal input to the interface conversion unit 213 is,
for example, digitally represented waveform signal which is
generated by spread processing and filtering processing, while
signal input to the interface conversion unit 4131 is, for example,
digitally represented waveform signal which is generated by IFFT
processing.
[0070] The D/A conversion unit 4221 converts the frequency-shifted
baseband signal to analog signal. The modulation unit 4222
modulates to frequencies corresponding to each service (e.g., 2
GHz) by performing quadrature modulation to I signal and Q signal
converted to analog signal.
[0071] The transmission amplification unit 4223 amplifies the
modulated signals corresponding to the two services and outputs
them to the antenna 5. The transmission amplification unit 4223 is
a common amplifier capable of amplifying both signals corresponding
to the two radio services A and B.
[0072] The antenna 5 transmits the amplified signals by radio
communication to information terminal such as a mobile phone or a
personal digital assistance (PDA). As a result, each radio service
can be provided to user.
[0073] In this manner, the radio communication system 100 in this
embodiment includes the second radio base station 4 as to enable
the use of the transmission amplifier 4223 which is a common
amplifier. Namely, the radio communication system 100 is configured
so that signals corresponding to two radio services (communication
formats) are time-multiplexed with the first service multiplex
separation unit 4135, signals of two different services are
respectively extracted by the second service multiplex separation
unit 4212, and after being frequency-shifted by the frequency
shifting unit 4213, are input to the common amplifier. Thus, the
radio communication system 100 can be in a shared state that
corresponds to two radio services. In addition, it is able to
provide at least two radio services, since the radio communication
system 100 performs processing by multiplexing signals
corresponding to two radio services.
[0074] Next, an explanation of the operation is provided while
moving uplink (direction in which signals are transmitted from the
antenna 5 to the first radio base station 2).
[0075] Signal received by the antenna 5 is converted to fixed
analog signal by the reception unit 4224, and is down-converted by
the down converter 4225 to a frequency enabling input to the A/D
conversion unit 4226 in a subsequent stage. The down-converted
signal is converted to digital signal by the A/D conversion unit
4226 and output to the third interface conversion unit 421.
[0076] The IQ extraction unit 4214 extracts I signals and Q signals
corresponding to each service from the digitally converted signal
and outputs those signals.
[0077] The second service multiplex separation unit 4212
multiplexes these baseband signals, converts to CPRI signal by
adding a header, and outputs. The CPRI signal in this case is
signal as depicted in FIG. 4(C), for example. The sixth conversion
unit 4211 converts the CPRI signal to optical signal and
outputs.
[0078] The fifth conversion unit 4138 converts optical signal from
the sixth conversion unit 4211 to CPRI signal which is electrical
signal, and the CPRI signal is separated into baseband signals of
each service by the first service multiplex separation unit 4135.
Processing precisely corresponding to the reverse of the processing
depicted in FIGS. 4(A) to 4(C) is performed. The baseband signal
corresponding to the radio service A is output to the fourth CPRI
processing unit 4137, while the baseband signal corresponding to
the radio service B is output to the third CPRI processing unit
4134.
[0079] The baseband signal corresponding to the radio service A is
converted to CPRI signal by the fourth CPRI processing unit 4137,
and further converted to optical signal by the fourth conversion
unit 4136. The optical signal is then converted to electrical
signal by the first conversion unit 2132 connected by the cable,
the electrical signal is converted to CPRI signal by the first CPRI
processing unit 2131, and the CPRI signal is output to the baseband
signal processing unit 212 depicted in FIG. 1. The baseband signal
is extracted from the CPRI signal by the first baseband signal
processing unit 212, and output to the first host apparatus 1 via
the first common control unit 211.
[0080] On the other hand, the baseband signal corresponding to the
radio service B is converted to CPRI signal by the third CPRI
processing unit 4134, and the CPRI signal is converted to optical
signal by the third conversion unit 4133. Subsequently, the
baseband signal is extracted from the CPRI signal by the second
conversion unit 4132 and the second CPRI processing unit 4131. The
extracted baseband signal is output as is without performing any
particular processing to the second baseband processing unit 412
depicted in FIG. 1, and then output to the second host apparatus 3
via the second common control unit 411.
Second Embodiment
[0081] The following provides an explanation of a second
embodiment. FIG. 5 is a drawing depicting an example of the
configuration of the radio communication system 100 in the second
embodiment. The same reference numerals are used to indicate those
portions of the radio communication system 100 of the second
embodiment that are the same as those of the first embodiment.
[0082] The second radio base station 4 of the radio communication
system 100 includes a third radio equipment (RE) 43. The third
radio equipment 43 is connected with the first and second interface
conversion units 213 and 413 via a cable, and can process the two
communication formats of the first and second radio equipment
controllers (REC) 21 and 41.
[0083] As depicted in FIG. 5, the configuration of the first radio
base station 2 and the configuration of the second interface
conversion unit 413 are the same as those of the first
embodiment.
[0084] The second interface conversion unit 413 of the second radio
base station 4 includes the second CPRI processing unit 4131 and
the second conversion unit 4132.
[0085] The third radio equipment 43 of the second radio base
station 4 includes a fourth interface conversion unit 431 and the
transmission and reception amplification unit 422. In addition, the
fourth interface conversion unit 431 includes a seventh conversion
unit 4311, a fifth CPRI processing unit 4312, an eighth conversion
unit 4313, a sixth CPRI processing unit 4314, the frequency shift
unit 4213 and the IQ extraction unit 4214. The configuration of the
transmission and reception amplification unit 422 is omitted from
the explanation since it is the same as that of the first
embodiment.
[0086] The operation of the principal portions of the radio
communication system 100 configured in this manner is as described
below. The first conversion unit 2132 of the first interface
conversion unit 213 outputs optical signal corresponding to the
radio service A. In addition, the second conversion unit 4132 of
the second interface conversion unit 413 outputs optical signal
corresponding to the radio service B.
[0087] The seventh conversion unit 4311 of the fourth interface
conversion unit 431 converts optical signal corresponding to the
radio service A to CPRI signal which is electrical signal, and the
fifth CPRI processing unit 4312 extracts I signal and Q signal
which is baseband signal from the converted CPRI signal.
[0088] The eighth conversion unit 4313 converts optical signal
corresponding to the radio service B to CPRI signal which is
electrical signal, and the sixth CPRI processing unit 4314 extracts
I signal and Q signal which is baseband signal from the converted
CPRI signal.
[0089] The frequency shift unit 4213 multiplexes signals of the
radio services employing two communication formats in the same
manner as the first embodiment. The frequencies of the signals of
the two radio services are shifted to prescribed frequency bands.
At that time, the frequency bands are prevented from overlapping.
An explanation of subsequent signal processing is omitted since it
is the same as that of the first embodiment.
[0090] Operation of the uplink direction is as follows. Namely,
baseband signals of each service corresponding to the two
communication formats in the I/Q extraction unit 4214 are output to
the fifth and sixth CPRI processing units 4312 and 4314, and are
respectively converted to each CPRI signal. The CPRI signals are
then converted to optical signals by the seventh and eighth
conversion units 4311 and 4313, after which they are output to the
first and second radio equipment controllers 21 and 42,
respectively.
[0091] As depicted in FIG. 5, the radio communication system 100 of
the second embodiment eliminates the need for providing separate
radio equipment corresponding to the first radio equipment
controller 21, thereby eliminating the need to intentionally
securing space for installing the radio equipment. The radio
communication system 100 effects obtained in the first embodiment
since it operates in the same manner as the first embodiment with
the exception of that described above.
Third Embodiment
[0092] The following provides an explanation of a third embodiment.
The third embodiment is an example of implementing two
communication formats in the same manner as the first embodiment by
combining and separating signals corresponding to two communication
formats on a frequency axis.
[0093] FIG. 6 is an example of the configuration of principal
portions of the radio communication system 100 of the third
embodiment. The same reference numerals are used to indicate those
portions of the radio communication system 100 of the third
embodiment that are the same as those of the first embodiment.
[0094] In comparison with the first embodiment, the second radio
base station 4 includes a third radio equipment controller (REC)
44, and the third radio equipment controller 44 includes a fifth
interface conversion unit 441.
[0095] The fifth interface conversion unit 441, includes, in
addition to the second through fourth CPRI processing units 4131,
4134 and 4137 and the second through fourth conversion units 4136,
a first time-frequency conversion unit 4411, a combining unit 4412,
a second time-frequency conversion unit 4413, a first
frequency-time conversion unit 4414, a seventh CPRI processing unit
4415, a ninth conversion unit 4416, a third time-frequency
conversion unit 4417, a separation unit 4418, and second and third
frequency-time conversion units 4419 and 4420. Furthermore, 4131,
4132 and 4133 are the same as previously described with respect to
being able to be omitted.
[0096] The following provides an explanation of downlink operation.
Namely, signal corresponding to the radio service A is input from
the first radio base station 2 to the fourth conversion unit 4136,
and converted from optical signal to CPRI signal which is
electrical signal. The fourth CPRI processing unit 4137 extracts I
signal and Q signal which is baseband signal from the converted
CPRI signal and outputs. The first time-frequency conversion unit
4411 converts I signal and Q signal on a time axis to I signal and
Q signal a frequency axis by a Fourier transform and the like and
outputs.
[0097] On the other hand, signal corresponding to the radio service
B is output to the second time-frequency conversion unit 4413 via
the second CPRI processing unit 4131, the second conversion unit
4132, the third conversion unit 4133, and the third CPRI processing
unit 4134. The second time-frequency conversion unit 4413 converts
I signal and Q signal on the time axis to I signal and Q signal on
the frequency axis by the Fourier transform and the like in the
same manner as the first time-frequency conversion unit 4411.
[0098] The combining unit 4412 inputs I signal and Q signal on the
frequency axis corresponding to the radio services A and B, and
combines signals by adding the two signals on the frequency axis on
the frequency axis.
[0099] The first frequency-time conversion unit 4414 again converts
the combined signals from the combining unit 4412 to I signal and Q
signal on the time axis by a reverse Fourier transform and the
like. It goes without saying that the converted signal is a signal
combined from signals corresponding to the two radio services.
[0100] The converted I signal and Q signal on the time axis is
converted to CPRI signal by the seventh CPRI processing unit 4415.
FIG. 7(C) is a drawing depicting an example of the format of CPRI
signal following conversion. As depicted in this drawing, two
signal combined on the frequency axis is inserted into the data
block region. Furthermore, FIG. 7(A) depicts an example of the
format of CPRI signal output from the fourth CPRI processing unit
4137, while FIG. 7(B) depicts an example of the format of CPRI
signal output from the third CPRI processing unit 4134.
[0101] Subsequently, the CPRI signal is converted to optical signal
by the ninth conversion unit 4416 and output to the second radio
equipment 42.
[0102] The sixth conversion unit 4211 of the third interface
conversion unit 421 converts the optical signal to CPRI signal
which is electric signal. The eighth CPRI processing unit 4218
extracts base band signal which is I signal and Q signal, from the
converted CPRI signal. As depicted in FIG. 7(C), since the CPRI
signals are already combined, the I signal and Q signal with which
the service A and B is combined is extracted, and the extracted I
signal and Q signal are output to a frequency mapping unit
4213.
[0103] The frequency mapping unit 4213 maps the extracted I signal
and Q signal to a predetermined frequency band. The mapped baseband
signal is then output to the transmission and reception
amplification unit 422.
[0104] An explanation of subsequent processing is omitted since it
is the same as that of the first embodiment.
[0105] Operation of the uplink direction is as follows.
[0106] Although signal received with the antenna 5 is processed in
the transmission and reception amplification unit 422, an
explanation thereof is omitted since processing in the transmission
and reception amplification unit 422 is the same as that of the
first embodiment.
[0107] The IQ extraction unit 4214 extracts I signal and Q signal
from digitally converted signal and outputs. The extracted I signal
and Q signal are in a state of combining the services A and B.
[0108] The eighth CPRI processing unit 4218 converts the baseband
signal to CPRI signal by, for example, adding a header and the like
thereto, and outputs the CPRI signals. The CPRI signal in this case
is signal like those depicted in FIG. 7(C), for example. The sixth
conversion unit 4211 converts the CPRI signal to optical signal and
outputs.
[0109] Signal from the second radio equipment 42 is output to the
third time-frequency conversion unit 4417 via the ninth conversion
unit 4416 and the seventh CPRI processing unit 4415.
[0110] The third time-frequency conversion unit 4417 converts I
signal and Q signal which is baseband signal from the seventh CPRI
processing unit 4415 to I signal and Q signal on the frequency axis
by the Fourier transform and the like.
[0111] The separation unit 4418 separates I signal and Q signal on
the frequency axis into I signals and Q signals of each radio
service. For example, the I signal and Q signal corresponding to
the radio service A are separated according to a certain
predetermined frequency band, while the I signal and Q signal
corresponding to the radio service B are separated according to
another predetermined frequency band. The I signal and Q signal
corresponding to the radio service A are output to the second
frequency-time conversion unit 4419, while the I signal and Q
signal corresponding to the radio service B are output to the third
frequency-time conversion unit 4420.
[0112] The second frequency-time conversion unit 4419 converts the
I signal and Q signal on the frequency axis to I signal and Q
signal on the time axis by the Fourier transform and the like and
then outputs. The converted I signal and Q signal are output to the
first radio base station 2 via the fourth CPRI processing unit 4137
and the fourth conversion unit 4136.
[0113] In addition, the third frequency-time conversion unit 4420
also converts the I signal and Q signal on the frequency axis to I
signal and Q signal on the time axis and outputs, the signals are
output from the fifth interface conversion unit 441 to the baseband
signal processing unit 412 (see FIG. 1). An explanation of
subsequent processing is omitted since it is the same as that of
the first embodiment.
[0114] In this third embodiment as well, since processing is
performed by combining signals of two communication formats by
deploying and adding the signals on the frequency axis, the radio
communication system 100 can be made to be corresponded with two
radio communication services in the same manner as the first
embodiment.
[0115] Furthermore, in this embodiment as well, the second
conversion unit 4132 and the sixth conversion unit 4211 can be
directly connected with the cable, thereby making it possible to
implement one service only.
Fourth Embodiment
[0116] Next, an explanation is provided of a fourth embodiment.
FIG. 8 is a drawing depicting an example of the configuration of
the principal portions of the radio communication system 100 in the
fourth embodiment. The fourth embodiment is an example in which the
first radio equipment controller 21 corresponding to the radio
service A and the second radio equipment 42 capable of processing
two communication formats are connected directly without going
through the second interface conversion unit 413 of the second
radio equipment controller 41 that processes a communication format
corresponding to the radio service B.
[0117] In this fourth embodiment, since a configuration is employed
that does not go through the second radio equipment controller 41,
when switching from the old second radio equipment controller 41 to
a new second radio equipment controller, the new second radio
equipment controller can be smoothly installed in the second radio
base station 4 while providing one of the radio services.
[0118] The configuration is the same as that of the first
embodiment with the exception of the first conversion unit 2132 and
the sixth conversion unit 4211 being connected, and the second
radio equipment controller 41 no longer being required. With
respect to processing, the second service multiplex separation unit
4212 does not performs multiplex processing or separation
processing, but rather directly outputs input CPRI signal to the
frequency shift unit 4213, and outputs the I signal and Q signal
which is input baseband signal directly to the sixth conversion
unit 4211. An explanation of subsequent processing is omitted since
it is the same as that of the first embodiment.
Fifth Embodiment
[0119] The following provides an explanation of a fifth embodiment.
FIG. 9 is a drawing depicting an example of the configuration of
principal portions of the radio communication system 100 in the
fifth embodiment. The same reference numerals are used to indicate
those portions of the fifth embodiment that are the same as those
of the first embodiment. Although the second interface conversion
unit 413 corresponding to the radio service B has multiplex and
separation function in the first embodiment, the first interface
conversion unit 213 corresponding to the radio service A has
multiplex and separation functions in this embodiment.
[0120] As depicted in FIG. 9, the second interface conversion unit
413 included in the second radio equipment controller 41 of the
second radio base station 4 includes the second CPRI processing
unit 4131 and the second conversion unit 4132.
[0121] On the other hand, the first interface conversion unit 213
included in the first radio equipment controller 21 of the first
radio base station 2 includes the third and fourth CPRI processing
units 4134 and 4137, the third and fourth conversion units 4133 and
4136, the first service multiplex separation unit 4135 and the
fifth conversion unit 4138 in addition to the first CPRI processing
unit 2131 and the first conversion unit 2132.
[0122] Signal corresponding to the radio service A can be output to
the first interface conversion unit 213 by connecting the fourth
conversion unit 4136 and the second conversion unit 4132 with an
optical cable, and the two multiplexed signals can be transmitted
from the second radio equipment 42 by connecting the fifth
conversion unit 4138 and the sixth conversion unit 4211.
[0123] Similar to the first embodiment, CPRI signal corresponding
to radio services A and B is multiplexed in the first multiplex
separation unit 4135. For example, the CPRI signal is multiplexed
by mapping to the prescribed region of the data block of the CPRI
format as depicted in FIG. 4(C).
[0124] In this manner, multiplex and separation functions of two
radio services can be performed in not only one interface
conversion unit, but also by another interface conversion unit in
this embodiment. Furthermore, since processing is performed in this
embodiment in the same manner as the first embodiment with the
exception of multiplex and separation processing being performed by
the first interface conversion unit 213, the same effects are
demonstrated as those of the first embodiment.
Other Embodiments
[0125] The following provides an explanation of other embodiments.
Although connection of the first conversion unit 2132 and the
fourth conversion unit 4136 with the optical cable is explained in
the first and third embodiments (see FIGS. 2 and 6), they may be
connected with a cable other than the optical cable. In addition,
the fourth conversion unit 4316 and the second conversion unit 4132
in the fifth embodiment may also be connected with a cable other
than the optical cable.
[0126] In addition, in the fifth embodiment, processing for
multiplexing and separating signal in the direction of the time
axis is performed in the first service multiplex separation unit
4135 of the first interface conversion unit 213 of the first radio
base station 2 corresponding to the radio service A. However,
combining processing on the frequency axis as explained in the
third embodiment may be performed in the first interface conversion
unit 213 instead of the first service multiplex separation unit
4135.
* * * * *