JP3934566B2 - Wireless base station system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radio base station system, and more particularly to a radio base station system in which a radio base station and a plurality of radio relay stations are daisy chain connected by a transmission cable.
[0002]
[Prior art]
As means for expanding the radio zone of a radio base station, the radio base station and a plurality of radio relay stations are daisy chain connected (cascade connected) using a transmission cable such as a coaxial cable or an optical fiber cable. That is, each radio relay station transmits a transmission signal transmitted from the radio base station via the transmission cable to the mobile station in the radio zone at the same radio frequency as the radio base station, and from the mobile station in the radio zone. The wireless base station system having a wide wireless zone is constructed by transmitting the received signal to the wireless base station via the transmission cable. (For example, refer to Patent Document 1.)
In a radio base station system using CDMA communication technology, two transmitters are used in the radio base station and the radio relay station in order to reduce the influence of multipath fading and ensure stable communication with the mobile station. In addition, a receiver is provided to perform transmission / reception by the diversity method. (For example, see Patent Document 2.)
[Patent Document 1]
JP 2002-185959 A
[Patent Document 2]
JP 2001-168778 A
[0003]
[Problems to be solved by the invention]
However, in the case of a wireless base station system connected in a daisy chain, if any failure occurs in the transmission cable, signal transmission between the lower wireless relay station connected to the failed transmission cable and the wireless base station is impossible. Therefore, it is impossible to provide a communication service for mobile stations in the radio zone of the corresponding radio relay station.
[0004]
In addition, in the case of a system that wirelessly connects between a radio base station and a radio relay station and between radio relay stations without using a transmission cable, it interferes with communication between the radio base station, the radio relay station, and the mobile station. In order not to give it, there is a problem that a wireless facility different from the wireless device used for communication between the wireless base station and the wireless relay station and the mobile station is required.
[0005]
An object of the present invention is to provide a wireless base station system in which a wireless base station and a plurality of wireless relay stations are daisy chain connected by a transmission cable, and even if a failure occurs in the transmission cable between the stations, another wireless facility is arranged. It is an object of the present invention to provide a radio base station system that can continue communication services between a radio base station, a radio relay station, and a mobile station.
[0006]
[Means for Solving the Problems]
In the radio base station system of the present invention, a radio base station apparatus and a plurality of radio relay apparatuses are daisy chain connected by a transmission cable, and the radio base station apparatus and the plurality of radio relay apparatuses are respectively a first transmitter and a second transmitter. And a first and second receiver, and a radio base station system that communicates with a mobile station by transmission diversity and reception diversity at the same frequency in radio zones formed by the radio base station device and a plurality of radio relay devices, respectively When the radio base station apparatus detects a failure of the transmission cable connected to the adjacent radio relay apparatus, the same signal is sent to the first transmitter and the second transmitter of the radio base station apparatus, respectively. And a transmission diversity signal generation unit that outputs a transmission baseband signal, and a transmission frequency of the second transmitter of the radio base station apparatus A control unit that changes to a predetermined first emergency frequency and changes a reception frequency of the second receiver of the radio base station apparatus to a predetermined second emergency frequency; A reception signal combining unit that combines signals received from the first receiver and the second receiver of a station apparatus and outputs a reception baseband signal, and the radio relay apparatus includes the radio base station When a failure of the transmission cable connected to the device is detected, the transmission frequency of the second transmitter of the wireless relay device is changed to the predetermined second emergency frequency, and the second receiver A control unit that changes a reception frequency to the predetermined first emergency frequency; and a signal included in the first emergency frequency received by the second receiver of the wireless relay device. Said first transmission of the device A transmission path and a transmission path to the radio relay apparatus located at a lower level connected by the transmission cable, and a lower level level connected by the transmission cable to the signal received by the first receiver of the radio relay apparatus A route setting unit configured to combine the signals received from the wireless relay device located in the wireless relay device and set a route to be transmitted by the second transmitter of the wireless relay device. .
[0007]
In the radio base station system of the present invention, the radio base station apparatus is a first radio relay apparatus that is one of the plurality of radio relay apparatuses, and the radio relay apparatus is the first radio relay apparatus. A second wireless relay device adjacent to the lower level of the wireless relay device .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described with reference to the drawings.
[0014]
FIG. 1 is a block diagram showing an example of a radio base station system according to the present invention.
[0015]
Here, an example of a radio base station system is shown in which a diversity-type radio base station apparatus 10 and a plurality of diversity-type radio relay station apparatuses 21 and 22 are daisy-chain connected by optical fiber cables 31 and 32, respectively.
[0016]
The radio base station apparatus 10 forms a radio zone 41, the radio relay station apparatus 21 forms a radio zone 42, and the radio relay station apparatus 22 forms a radio zone 43. Further, since the radio relay station apparatuses 21 and 22 have the same configuration and transmit at the same frequency as the radio frequency of the radio base station apparatus 10, the mobile stations 51 and 52 located in the radio zone communicate without switching the frequency. Is possible.
[0017]
FIG. 2 is a block diagram illustrating an example of the radio base station apparatus 10 and the radio relay station apparatus 21.
[0018]
First, the configuration of the radio base station apparatus 10 will be described.
[0019]
The radio base station apparatus 10 converts the transmission baseband signal transmitted to the radio relay station apparatus 21 into an optical signal by converting the transmission baseband signal transmitted to the radio transmission / reception section 110 and the radio relay station apparatus 21 using the two antennas 101 and 102 by the diversity method. An electrical / optical conversion unit (E / O) 120 that outputs to the optical fiber cable 31-1, and an optical signal transmitted from the wireless relay station device 21 via the upstream optical fiber cable 31-2 is converted into an electrical signal ( The optical / electrical conversion unit (O / E) 130 that converts the received baseband signal), the reception output signal of the wireless transmission / reception unit 110 and the output signal of the optical / electrical conversion unit (O / E) 130 are combined to provide a reception base. A combining unit 140 that outputs the signal as a band signal and a control unit (CPU) 150 that controls each unit when a failure occurs in the optical fiber cable are provided.
[0020]
By the way, as a diversity technique, there are a space diversity system for receiving by a plurality of spatially separated antennas and a transmission diversity system for obtaining a diversity effect on the receiving side by transmitting the same information by performing different encoding processes.
[0021]
Here, the transmission system of the wireless transmission / reception unit 110 transmits a transmission diversity signal generation circuit 111 that generates two different transmission diversity signals from a transmission baseband signal and two transmission diversity signals in order to perform transmission by a transmission diversity method. First and second transmitters (TX1, TX2) 112, 113 for converting the signals into predetermined transmission frequency signals and transmitting them through circulators 114, 115 and antennas 101, 102, respectively.
[0022]
In addition, the reception system of the wireless transmission / reception unit 110 includes first and second receivers (RX1, RX2) 116, 117 that receive diversity signals from mobile stations in wireless zones separated by the circulators 114, 115, respectively. is doing. The reception output signals of the receivers (RX1, RX2) 116, 117 are combined by the combining unit 140 and output as reception baseband signals.
[0023]
The optical / electrical converter (O / E) 130 has a function of converting an optical signal transmitted from the wireless relay station device 21 via the optical fiber cable 31-2 into an electric signal, and also an optical fiber cable 31-. 2 has a function of detecting an input disconnection of an optical signal due to occurrence of a failure such as disconnection 2 and outputting an optical signal disconnection detection signal Sd21, and a function of extracting and receiving an optical signal disconnection control signal Sc21 multiplexed with the optical signal. ing. The optical signal interruption detection signal Sd21 and the optical signal interruption control signal Sc21 are output to the control unit (CPU) 150.
[0024]
In addition to the function of converting the transmission baseband signal into an optical signal, the electrical / optical conversion unit (E / O) 120 outputs from the control unit (CPU) 150 when an optical signal input interruption is detected. The optical signal interruption control signal Sc12 is multiplexed with the optical signal.
[0025]
Next, the configuration of the radio relay station device 21 will be described.
[0026]
The radio relay station apparatus 21 is transmitted from the radio base station apparatus 10 via the downlink optical fiber cable 31-1 and the radio transmission / reception unit 210 that performs transmission / reception by the diversity method using the two antennas 201 and 202. An optical / electrical converter (O / E) 220 that converts an incoming optical signal into an electrical signal (transmission baseband signal) and a transmission baseband signal that is sent to the next radio relay station device 22 (not shown) as an optical signal An electrical / optical converter (E / O) 230 that converts and outputs to the downstream optical fiber cable 32-1,
An optical / electrical converter (O / O) that converts an optical signal transmitted from the next wireless relay station device 22 (not shown) through the upstream optical fiber cable 32-2 into an electrical signal (reception baseband signal). E) 240, a combining unit 250 that combines the reception output signal of the wireless transmission / reception unit 210 and the output signal of the optical / electrical conversion unit (O / E) 240 and outputs the combined signal as a reception baseband signal, and an output signal of the combining unit 250 An electrical / optical conversion unit (E / O) 260 that converts the signal into an optical signal and sends it to the radio base station apparatus 10 via the optical fiber cable 31-2 for upstream signals;
A control unit (CPU) 270 that controls each unit when a failure occurs in the optical fiber cable, and first and second switches 280 that are controlled by the control unit (CPU) 270 to switch the signal path when a failure occurs in the optical fiber cable. , 290.
[0027]
Here, the radio transmission / reception unit 210 has basically the same configuration as that of the radio transmission / reception unit 110 of the radio base station apparatus 10, and the transmission system generates two different encoded transmission diversity signals from the transmission baseband signal. Transmission diversity signal generation circuit 211, and first and second transmitters (TX1, TX2) that convert two transmission diversity signals into predetermined transmission frequency signals and transmit the signals through circulators 214, 215 and antennas 201, 202, respectively. 212, 213.
[0028]
The receiving system also includes first and second receivers (RX1, RX2) 216, 217 that receive diversity signals from mobile stations in radio zones separated by circulators 214, 215, respectively.
[0029]
The first switch 280 receives the output signal of the optical / electrical conversion unit (O / E) 220 and the output signal of the second receiver (RX2) 217 of the wireless transmission / reception unit 210, and selects one of them to select the electric signal. Output to the transmission diversity signal generation circuit 211 of the / optical converter (E / O) 230 and the wireless transceiver 210.
[0030]
The second switch 290 receives the output signal of the combining unit 250 and one output signal of the transmission diversity signal generation circuit 211 of the wireless transmission / reception unit 210, selects one of them, and outputs the second signal of the wireless transmission / reception unit 210. The data is output to the transmitter (TX2) 213.
[0031]
Similarly to the optical / electrical converter (O / E) 130 of the radio base station apparatus 10, the optical / electrical converters (O / E) 220 and 240 electrically convert the optical signal transmitted via the optical fiber cable. In addition to the function of converting each into a signal, the function of detecting the input disconnection of the optical signal due to the disconnection of the optical fiber cable and outputting the optical signal disconnection detection signals Sd12 and Sd32 respectively, and the optical signal multiplexed into the optical signal The disconnection control signals Sc12 and Sc32 are extracted. The optical signal disconnection detection signals Sd12 and Sd32 and the optical signal disconnection control signals Sc12 and Sc32 are sent to the control unit (CPU) 270.
[0032]
Similarly to the electrical / optical conversion unit (E / O) 120 of the radio base station apparatus 10, the electrical / optical conversion units (E / O) 230 and 260 convert the transmission baseband signal and the reception baseband signal to optical signals. In addition to the function of converting the optical signal to the optical signal, the optical signal cutoff control signals Sc23 and Sc21 output from the control unit (CPU) 270 when the optical signal input cutoff is detected are multiplexed with the optical signal. .
[0033]
By the way, when a failure occurs in the optical fiber cable, the optical signal transmitted from the electrical / optical conversion unit (E / O) is not input to the opposing optical / electrical conversion unit (O / E). Therefore, when the optical / electrical conversion unit (O / E) detects an optical signal input interruption, it can be determined that a failure has occurred in the optical fiber cable.
[0034]
Further, when a failure occurs in the optical fiber cable, the signal transmitted through the optical fiber cable until then is wirelessly transmitted using one of the two wireless transmission / reception systems for diversity. As shown in FIG. 3, even if a failure occurs in the optical fiber cable, the communication service can be continued without stopping. The present invention is configured by paying attention to this point.
[0035]
Next, the operation will be described.
[0036]
First, the flow of a transmission signal when the optical fiber cables 31-1 and 31-2 connected between the radio base station apparatus 10 and the radio relay station apparatus 21 are normal will be described.
[0037]
Transmission baseband signals transmitted from the radio base station apparatus 10 to the radio relay station apparatus 21 and the radio zone 41 are supplied to the electrical / optical conversion unit (E / O) 120 and the radio transmission / reception unit 110, respectively.
[0038]
The transmission baseband signal supplied to the electrical / optical conversion unit (E / O) 120 is converted into an optical signal and transmitted to the radio relay station device 21 via the downstream optical fiber cable 31-1.
[0039]
Further, the transmission baseband signal supplied to the wireless transmission / reception unit 110 is converted into two transmission diversity signals by the transmission diversity signal generation circuit 111, and the first and second transmitters (TX1, TX2) 112, 113 and the circulator 114 are used. , 115, respectively, and then transmitted to the wireless zone 41 via the antennas 101, 102 by the transmission diversity method.
[0040]
In the radio relay station apparatus 21, normally, as shown, the first switch 280 selects the output signal of the optical / electrical converter (O / E) 220, and the second switch 290 transmits. One output signal of the diversity signal generation circuit 211 is selected.
[0041]
An optical signal transmitted from the radio base station apparatus 10 to the radio relay station apparatus 21 via the optical fiber cable 31-1 is converted into an electric signal (transmission baseband signal) by the optical / electrical converter (O / E) 220. After that, the signal is supplied to the electrical / optical conversion unit (E / O) 230 and the transmission diversity signal generation circuit 211 of the wireless transmission / reception unit 210 via the first switch 280.
[0042]
The electrical signal (transmission baseband signal) supplied to the electrical / optical conversion unit (E / O) 230 is converted again into an optical signal and sent to the next radio relay station device 22 via the optical fiber cable 32-1. The
[0043]
The electrical signal (transmission baseband signal) supplied to the transmission diversity signal generation circuit 211 is converted into two transmission diversity signals, one of which is supplied to the first transmitter (TX1) 212, and the other is the second transmission signal. The signal is supplied to the second transmitter (TX2) 213 via the switch 290. Then, the signal is transmitted to the wireless zone 42 by the transmission diversity method at the same transmission frequency as that of the wireless base station apparatus 10 via the antennas 201 and 202 via the circulators 214 and 215.
[0044]
Next, the flow of the received signal will be described.
[0045]
In the radio relay station device 21, radio signals from the mobile station 52 in the radio zone 42 are diversity-received by the antennas 201 and 202, separated by the circulators 214 and 215 of the radio transmission / reception unit 210, and received by the first and second receptions. Are supplied to the units (RX1, RX2) 216, 217. Then, the output signals of the first and second receivers are combined by the combining unit 250.
[0046]
The optical signal transmitted from the next wireless relay station device 22 via the optical fiber cable 32-2 is converted into an electrical signal by the optical / electrical converter (O / E) 240 and synthesized by the synthesis unit 250. Is done. That is, the output signals of the first and second receivers (RX1, RX2) 216, 217 and the output signal of the optical / electrical converter (O / E) 240 are combined by the combining unit 250.
[0047]
The combined output signal of the combining unit 250 is converted into an optical signal by an electrical / optical conversion unit (E / O) 260 and sent to the radio base station apparatus 10 via the optical fiber cable 31-2.
[0048]
Similarly, in the radio base station apparatus 10, the radio signal from the mobile station 51 in the radio zone 41 is diversity-received by the antennas 101 and 102, separated by the circulators 114 and 115 of the radio transceiver 110, and the first and first 2 receivers (RX1, RX2) 116, 117. The output signals of the first and second receivers (RX1, RX2) 116, 117 are combined by the combining unit 140.
[0049]
The optical signal transmitted from the radio relay station device 21 via the optical fiber cable 31-2 is converted into an electric signal by the optical / electrical converter (O / E) 130 and is combined by the combining unit 140. . That is, the output signals of the first and second receivers (RX1, RX2) 116, 117 and the output signal of the optical / electrical converter (O / E) 240 are combined by the combining unit 250 and output as a received baseband signal. Is done.
[0050]
Since the radio relay station device 22 is the same as the radio relay station device 21, all mobile stations in each radio zone of the radio base station device 10 and the plurality of radio relay station devices 21 and 22 are radio base stations. Communication with the device 10 becomes possible.
[0051]
Next, an operation when a failure occurs in the optical fiber cable will be described.
[0052]
FIG. 3 is a diagram showing a communication state of the radio base station system when a failure occurs in the optical fiber cable 31.
[0053]
4 is a flowchart showing an operation example of the control unit (CPU) 150 of the radio base station apparatus 10, and FIG. 5 is a flowchart showing an operation example of the control unit (CPU) 270 of the radio relay station apparatus 21.
[0054]
Here, a case where a failure occurs in the optical fiber cable 31-2 that transmits a signal from the radio relay station device 21 to the radio base station device 10 is shown as an example.
[0055]
First, the optical / electrical conversion unit (O / E) 130 of the radio base station apparatus 10 detects the input interruption of the optical signal from the optical fiber cable 31-2, and sends the optical signal interruption detection signal Sd21 to the control unit (CPU) 150. To send.
[0056]
In FIG. 4, the control unit (CPU) 150 determines that a failure has occurred in the optical fiber cable 31-2 by receiving the optical signal disconnection detection signal Sd21 (step 401).
[0057]
Then, the transmission diversity signal generation circuit 111 is instructed to output to the second transmitter (TX2) 113 the same signal that has been output to the first transmitter (TX1) 112 until then. (Step 402) The second transmitter (TX2) 113 is changed so that the transmission frequency that has been the same as that of the first transmitter (TX1) 112 is changed to a predetermined emergency frequency f1. Instruct (Step 403), and also instruct the second receiver (RX2) 117 to change the reception frequency to a predetermined emergency frequency f2 (Step 404).
[0058]
Further, after the optical signal disconnection control signal Sc12 is transmitted to the electrical / optical conversion unit (E / O) 120 and multiplexed with the optical signal, the electrical signal transmission operation of the electrical / optical conversion unit (E / O) 120 is performed. Is stopped (step 405).
[0059]
On the other hand, the optical / electrical conversion unit (O / E) 220 of the radio relay station device 21 receives the optical signal disconnection control signal Sc12 multiplexed with the optical signal and sends it to the control unit (CPU) 270. Further, the transmission / stop control of the electrical / optical conversion unit (E / O) 120 of the radio base station apparatus 10 causes the optical signal disconnection detection signal Sd12 to be output to the control unit (CPU) 270.
[0060]
In FIG. 5, the control unit (CPU) 270 of the radio relay station device 21 receives the optical signal disconnection control signal Sc12 from the optical / electrical conversion unit (O / E) 220, so that the optical fiber cable 31-2 has a fault. It is determined that it has occurred (step 501).
[0061]
Then, the second transmitter (TX2) 213 is instructed to change the transmission frequency to the emergency frequency f2 (step 502), and the second receiver (RX2) 217 is set with the reception frequency. An instruction is given to change to the emergency frequency f1 (step 503).
[0062]
Further, the first and second switches 280 and 290 are instructed to switch signals. That is, the first switch 280 is caused to select the output signal of the second receiver (RX2) 217 (step 504), and the second switch 290 is caused to select the output signal of the combining unit 250 (step 505).
[0063]
As described above, the control unit (CPU) 150 of the radio base station apparatus 10 and the control unit (CPU) 270 of the radio relay station apparatus 21 control the respective units, so that the radio base station apparatus 10 can control the optical fiber cable 31-1. The transmission baseband signal transmitted to the wireless relay station device 21 via the wireless base station device 21 and the received baseband signal (combined) transmitted from the wireless relay station device 21 to the wireless base station device 10 via the optical fiber cable 31-2. The output signal of the unit 250 can be transmitted without going through the optical fiber cable.
[0064]
That is, the transmission baseband signal that has been transmitted from the radio base station apparatus 10 to the radio relay station apparatus 21 through the optical fiber cable 31-1 until then is transmitted to the second transmitter (TX2) 113, the circulator 115, and the antenna 102. Is transmitted to the radio relay station device 21 via the emergency frequency f1, received by the antenna 202 of the radio relay station device 21, separated by the circulator 215 of the radio transceiver 210, and a second receiver having the reception frequency f1. (RX2) 217 is supplied.
[0065]
The output signal of the second receiver (RX2) 217 is supplied to the first switch 280 and the combining unit 250. The output signal of the second receiver supplied to the first switch 280 is supplied to the electrical / optical converter (E / O) 230 via the first switch 280.
[0066]
In addition, the reception baseband signal (the output signal of the combining unit 250) that the wireless relay station device 21 has transmitted to the wireless base station device 10 through the optical fiber cable 31-2 until then passes through the second switch 290. Is supplied to the second transmitter (TX2) 213 and transmitted to the radio base station apparatus 10 at the emergency frequency f2 via the circulator 115 and the antenna 102.
[0067]
Then, the signal is received by the antenna 102 of the radio base station apparatus 10, separated by the circulator 115 of the radio transceiver 110, and supplied to the second receiver (RX2) 117 having the reception frequency f2, and the output of the second receiver The signal is combined with the output signal of the first receiver (RX1) 116 in the combining unit 140 and output as a reception baseband signal.
[0068]
Thus, even if a failure occurs in the optical fiber cable between the radio base station apparatus 10 and the radio relay station apparatus 21, as shown in FIG. 3, one of the two transmission / reception systems of the diversity system is used. Can be used for wireless transmission and the other transmission / reception system can continue communication services with mobile stations in the wireless zone.
[0069]
In the above description, the case where a failure occurs in the upstream optical fiber cable 31-2 connected between the wireless base station device 10 and the wireless relay station device 21 is described as an example. Even when a failure occurs in the optical fiber cable 31-1, or even when a failure occurs in both the upstream optical fiber cable 31-2 and the downstream optical fiber cable 31-1, Furthermore, even when a failure occurs in the optical fiber cable between other devices, the same operation can be performed.
[0070]
Here, when a failure occurs in both the upstream optical fiber cable 31-2 and downstream optical fiber cable 31-1, the optical / electrical converter (O / E) 130 of the radio base station apparatus 10 and Since both the optical / electrical conversion unit (O / E) 220 of the wireless relay station device 21 detects the optical signal input disconnection and sends the optical signal disconnection detection signals Sd21 and Sd12 to the control units (CPU) 150 and 270, respectively. Control units (CPU) 150 and 270 determine that a failure has occurred in optical fiber cables 31-2 and 31-1, respectively, and control optical signal disconnection for electrical / optical conversion units (E / O) 120 and 260, respectively. After the signals Sc12 and Sc21 are multiplexed with the optical signal, the optical / optical conversion units (E / O) 120 and 260 are each instructed to stop the optical signal transmission operation.
[0071]
However, in this case, since the optical fiber cables 31-2 and 31-1 are faulty, the optical signal disconnection control signals Sc12 and Sc21 are not transmitted, but the control units (CPUs) 150 and 270 Regardless of whether or not the signal disconnection control signals Sc12 and Sc21 are received, signals transmitted through the optical fiber cable up to now in accordance with the optical signal disconnection detection signals Sd21 and Sd12 are included in two diversity transmission / reception systems. Each unit is controlled to wirelessly transmit using one of the above.
[0072]
FIG. 6 is a block diagram showing another example of the radio base station system according to the present invention.
[0073]
Here, the radio base station apparatus 10 has a diversity system configuration having two antennas, but the radio relay station apparatuses 23 and 24 show a radio base station system that is not a diversity system using one antenna.
[0074]
FIG. 7 is a diagram illustrating a communication state of the radio base station system when a failure occurs in the optical fiber cable 31 between the radio base station device 10 and the radio relay station device 23.
[0075]
In this case, the signal that has been transmitted through the optical fiber cable 31 is transmitted using one of the diversity transmission / reception systems of the radio base station apparatus 10 and the transmission / reception system of the radio relay station apparatus 23. Wireless transmission.
[0076]
FIG. 8 is a block diagram illustrating an example of the radio base station apparatus 10 and the radio relay station apparatus 23. Here, the same components as those shown in FIG.
[0077]
The radio base station apparatus 10 is the same as the radio base station apparatus 10 shown in FIG.
[0078]
The radio relay station device 23 converts an optical signal transmitted from the radio base station device 10 through the optical fiber cable 31-1 into an electrical signal (transmission baseband signal) (O / E). 220 and an electrical / optical converter that converts the signal selected by the first switch 280 into an optical signal and sends it to the next radio relay station device 24 (not shown) via the downstream optical fiber cable 32-1. (E / O) 230,
A transmitter (TX) 212 that converts a signal selected by the second switch 290 into a predetermined transmission frequency signal and transmits the signal via the circulator 214 and the antenna 201, and a receiver that receives the signal separated by the circulator 214 ( RX) 216,
An optical / electrical converter (O / E) 240 that converts an optical signal transmitted from the wireless relay station device 24 (not shown) through the optical fiber cable 32-2 into an electrical signal (received baseband signal); A combining unit 250 that combines the reception output signal of the receiver (RX) 216 and the output signal of the optical / electrical conversion unit (O / E) 240 and outputs the combined signal as a reception baseband signal, and the output signal of the combining unit 250 as an optical signal And an electric / optical conversion unit (E / O) 260 that transmits the data to the radio base station apparatus 10 via the optical fiber cable 31-2 and a control unit (CPU) 270 that controls each unit when a failure occurs in the optical fiber cable. And.
[0079]
Here, an operation when a failure occurs in the optical fiber cable 31-2 that transmits a signal from the radio relay station device 23 to the radio base station device 10 will be described.
[0080]
First, the optical / electrical conversion unit (O / E) 130 of the radio base station apparatus 10 detects an optical signal input interruption and sends an optical signal interruption detection signal Sd21 to the control unit (CPU) 150. The control unit (CPU) 150 instructs the transmission diversity signal generation circuit 111 to output the same signal to the second transmitter (TX2) 113 in response to the optical signal break detection signal Sd21, and the second The transmitter (TX2) 113 is instructed to change to the predetermined emergency frequency f1, and the second receiver (RX2) 117 is set to the predetermined emergency frequency f2. Instruct to change.
[0081]
Further, after the optical signal disconnection control signal Sc12 is transmitted to the electrical / optical conversion unit (E / O) 120 and multiplexed with the optical signal, the electrical signal transmission operation of the electrical / optical conversion unit (E / O) 120 is performed. To stop.
[0082]
On the other hand, the control unit (CPU) 270 of the radio relay station device 23 receives the optical signal disconnection control signal Sc12 from the optical / electrical conversion unit (O / E) 220, and also performs electrical / optical conversion of the radio base station device 10. It is determined that a failure has occurred in the optical fiber cable 31-2 by receiving the optical signal disconnection detection signal Sd12 due to the transmission stop control of the unit (E / O) 120.
[0083]
Then, the control unit (CPU) 270 instructs the transmitter (TX) 212 to change the transmission frequency to the emergency frequency f2, and the receiver (RX) 216 uses the reception frequency as an emergency. Instruct to change to frequency f1.
[0084]
Further, the first switch 280 selects the output signal of the receiver (RX) 216, and the second switch 290 selects the output signal of the combining unit 250.
[0085]
As described above, the control unit (CPU) 150 of the radio base station apparatus 10 and the control unit (CPU) 270 of the radio relay station apparatus 23 control the respective units. -1 is transmitted to the radio relay station apparatus 23 via the second transmitter (TX2) 113, the circulator 115 and the antenna 102 to the radio relay station apparatus 23 via the emergency frequency f1. It is transmitted, received by the antenna 201 of the radio relay station device 23, separated by the circulator 214, and supplied to the receiver (RX) 216 having the reception frequency f 1.
[0086]
An output signal of the receiver (RX) 216 is supplied to the first switch 280 and the combining unit 250. The output signal of the receiver (RX) 216 supplied to the first switch 280 is supplied to the electrical / optical conversion unit (E / O) 230 via the first switch 280 and via the optical fiber cable 32-1. To the next wireless relay station device 24.
[0087]
In addition, the reception baseband signal (the output signal of the combining unit 250) that the wireless relay station device 23 has transmitted to the wireless base station device 10 through the optical fiber cable 31-2 until then is transmitted via the second switch 290. To the transmitter (TX) 212 and transmitted to the radio base station apparatus 10 at the emergency frequency f2 via the circulator 214 and the antenna 201.
[0088]
Then, the signal is received by the antenna 102 of the radio base station apparatus 10, separated by the circulator 115 of the radio transceiver 110, and supplied to the second receiver (RX2) 117 having the reception frequency f2, and the output of the second receiver The signal is combined with the output signal of the first receiver (RX1) 116 in the combining unit 140 and output as a reception baseband signal.
[0089]
If a failure occurs in the optical fiber cable 31 between the radio base station apparatus 10 and the radio relay station apparatus 23, one of the diversity transmission / reception systems of the radio base station apparatus 10 and the radio relay station Since wireless transmission is performed using the transmission / reception system of the device 23, the communication service for the wireless zone 42 of the wireless relay station device 23 is hindered, but the transmission power of the wireless base station device 10 and the wireless relay station device 24 is increased. If the service area of the adjacent wireless zones 41 and 43 is expanded by controlling the above, the influence can be reduced.
[0090]
【The invention's effect】
As described above, according to the present invention, in a radio base station system in which a radio base station and a plurality of radio relay stations are daisy chain connected by a transmission cable, the radio base station and the plurality of radio relay stations are used for diversity. Each system is equipped with a wireless transmission / reception system, and when a transmission cable fails, signal transmission between stations connected by the transmission cable is used for one of the two wireless transmission / reception systems for diversity. By wireless transmission, the communication service can be continued without separately arranging wireless facilities.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an example of a radio base station system according to the present invention.
2 is a block diagram showing an example of a radio base station apparatus 10 and a radio relay station apparatus 21 shown in FIG.
3 is a diagram showing a communication state when a failure occurs in the optical fiber cable 31 in the radio base station system shown in FIG. 1. FIG.
4 is a flowchart showing an operation example of a control unit (CPU) 150 of the radio base station apparatus 10 shown in FIG.
5 is a flowchart showing an operation example of a control unit (CPU) 270 of the radio relay station device 21 shown in FIG.
FIG. 6 is a block diagram showing another example of a radio base station system according to the present invention.
7 is a diagram showing a communication state when a failure occurs in the optical fiber cable 31 in the radio base station system shown in FIG.
8 is a block diagram showing an example of a radio base station apparatus 10 and a radio relay station apparatus 23 shown in FIG.
[Explanation of symbols]
10 Radio base station equipment
21, 22 Radio relay station apparatus
31, 32 Optical fiber cable
101,102 antenna
110 Wireless transceiver
111 Transmit Diversity Signal Generation Circuit
114, 115 Circulator
112,113 first and second transmitters (TX1, TX2)
116,117 First and second receivers (RX1, RX2)
120 Electrical / Optical Conversion Unit (E / O)
130 Optical / electrical converter (O / E)
140 Synthesizer
150 Control unit (CPU)
201, 202 Antenna
210 Wireless transceiver
212,213 First and second transmitters (TX1, TX2)
216, 217 first and second receivers (RX1, RX2)
220,240 Optical / electrical converter (O / E)
230, 260 Electric / optical converter (E / O)
250 Synthesizer
270 Control unit (CPU)
280 First switch
290 Second switch

Claims (2)

A radio base station apparatus and a plurality of radio relay apparatuses are daisy chain connected by a transmission cable, and the radio base station apparatus and the plurality of radio relay apparatuses are respectively a first transmitter and a second transmitter, and a first receiver and a second receiver. In a radio zone formed by the radio base station device and a plurality of radio relay devices, respectively, in a radio base station system that communicates with a mobile station at the same frequency by transmission diversity and reception diversity,
When the radio base station device detects a failure of the transmission cable connected to the adjacent radio relay device,
A transmission diversity signal generation unit that outputs a transmission baseband signal to each of the first transmitter and the second transmitter of the radio base station apparatus using the same signal;
The transmission frequency of the second transmitter of the radio base station apparatus is changed to a predetermined first emergency frequency, and the reception frequency of the second receiver of the radio base station apparatus is predetermined A control unit for changing to the second emergency frequency;
A reception signal combining unit that combines signals received from the first receiver and the second receiver of the radio base station apparatus and outputs a reception baseband signal,
When the wireless relay device detects a failure of the transmission cable connected to the wireless base station device,
The transmission frequency of the second transmitter of the wireless relay device is changed to the predetermined second emergency frequency, and the reception frequency of the second receiver is changed to the predetermined first emergency frequency. A control unit for changing to a frequency;
A signal included in the first emergency frequency received by the second receiver of the wireless relay device is transmitted by the first transmitter of the wireless relay device and connected to the lower level by the transmission cable. A route to be transmitted to the wireless relay device that is located, and a signal received by the first receiver of the wireless relay device and a signal received from the wireless relay device that is located at a lower level connected by the transmission cable are combined. And a route setting unit for setting a route to be transmitted by the second transmitter of the wireless relay device.
A wireless base station system . The radio base station apparatus is a first radio relay apparatus that is one of the plurality of radio relay apparatuses, and the radio relay apparatus is adjacent to a lower level of the first radio relay apparatus. The radio base station system according to claim 1, wherein the radio base station system is a radio relay apparatus .

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