JP4374461B2 - Optical transmission system - Google Patents

Description

  The present invention relates to an optical transmission system for covering a dead zone of mobile communication, and in particular, when connecting more than a number of slave station devices connectable to one master station device, the base station device already has a master station device. Can be added to the system in which the signal level between the devices is properly adjusted and the output level of the base station device and the master station device is not adjusted again. About the system.

In recent years, mobile communication service area expansion projects promoted by each telecommunications carrier have almost completed the installation of base station facilities for major area services, and are now working to improve deadlines and measures for dead zones where radio waves do not reach The policy has been changed. Mobile communication dead zones include tunnels, underground malls, and buildings, and as countermeasures against mobile communication dead zones, countermeasure equipment that matches the characteristics of these various dead zones has been developed and used. ing.
As part of the countermeasures for the dead zone, an optical transmission system for providing a mobile communication service in the dead zone has been developed and provided.

As a prior art of an optical transmission system that covers a dead zone of a mobile communication system, Japanese Patent Laid-Open No. 11-234200 “Relay System” (Applicant: Kokusai Electric Co., Ltd., Inventor: Now) published on August 27, 1999 Yoshihiro So) has been proposed.
The above prior art converts a signal to be relayed received from a public line network from a high frequency signal to an optical signal in a central fixed station, and outputs it through an optical fiber to a plurality of relay fixed stations distributed in a dead zone. In the relay fixed station, the optical signal is converted into a high-frequency signal and radiated in the dead zone via the leaky coaxial cable, so that various signals can be relayed to the dead zone with a simple configuration, and the central fixed station and the relay fixed station By providing an optical branching device or an optical star coupler between the two, the service area of the dead zone can be expanded.

JP-A-11-234200 (pages 8-10, FIGS. 1, 4-5)

A conventional general optical transmission system that provides a mobile communication service in a dead zone will be described with reference to FIG. FIG. 3 is a configuration block diagram of a conventional general optical transmission system in which two master station devices (a master master device and a slave master device) are connected to a base station device.
In FIG. 3, the optical transmission system is connected to a base station apparatus (BTS (Base Tranceiver Station) in the figure) 1, a master station apparatus 4a (master master station apparatus) and 4b (slave master station apparatus), and a master station apparatus 4a. A plurality of slave station devices 5a-1 to 5a-m and a plurality of slave station devices 5b-1 to 5b-n connected to the master station device 4b.
In the optical transmission system of FIG. 3, the base station device 1 and the master station devices 4a and 4b are usually installed in a concentrated manner at a communication carrier station or the like, and the slave station devices 5a and 5b are installed in a dead zone to be communicated. The

  The master station devices 4a and 4b are connected to the base station device 1 through a coaxial cable, and perform bidirectional communication using electrical signals in a frequency band used for mobile communication. The coaxial cable is provided for each communication direction and for each frequency band. One end of the coaxial cable for downstream communication is connected to the output terminal (RF_OUT in the figure) of the base station apparatus 1 and the other end is branched by the distributor 6. Then, it is connected to the connector of the downlink connector group 44 in the master station devices 4a and 4b. Also, the coaxial cable for upstream communication is branched at one end and connected to the connector of the uplink connector group 45-1 or 45-2 in the master station devices 4a and 4b, and the other end is integrated by the combiner 7, It is connected to the input terminal (RF_IN in the figure) of the station apparatus 1. That is, the distributor 6 is provided on a coaxial cable for downstream communication for each frequency band, and the combiner 7 is provided on a coaxial cable for upstream communication for each frequency band.

  In the master station devices 4a and 4b, a connector for connecting a coaxial cable is provided for each frequency band in the downlink connector group 44 and the uplink connector group 45, and the electrical in the corresponding frequency band is connected via the connector. Signals are input and output.

  The master station device 4a is connected to the slave stations 5a-1 to 5a-m, and the master station device 4b is connected to the slave station devices 5b-1 to 5b-n via optical fibers, respectively. I do. An optical fiber is provided for each slave station device for each communication direction, and one end of an optical cable for downstream communication is an electrical / optical conversion unit (E / O unit in the figure, hereinafter referred to as this notation) in each master station device. The other end is connected to the corresponding slave station device 5a or 5b. The upstream optical fiber has one end connected to each slave station device 5a or 5b, and the other end connected to an optical / electrical conversion unit (O / E unit in the figure, hereinafter referred to as this notation) 43 in each master station device. Connected to.

In the master station devices 4a and 4b in FIG. 3, the signal processing for the downlink communication is performed in the series of the downlink connector group 44, the combiner 411, and the E / O unit 42, and the signal processing for the uplink communication is O / O This is performed in the sequence of the E unit 43, the distributor 412 and the uplink connector group 45.
In addition, the master station devices 4a and 4b in FIG. 3 are provided with two sequences for performing upstream communication signal processing. In consideration of the influence of fading in wireless communication, the base station device 1 This is to cope with a case where a diversity system that handles a signal with a high reception level as regular communication data among uplink signals processed in a plurality of streams is adopted. In the system of FIG. 3, the base station apparatus 1 does not employ a diversity system, and the master station apparatuses 4a and 4b include an O / E unit 43-1, a distributor 412-1 and an uplink connector group 45-1. It is used as a sequence for performing signal processing for uplink communication.

  A specific communication processing operation of the optical transmission system of FIG. 3 will be described for each communication direction. First, in the downlink communication processing operation, the communication data of the mobile communication system transmitted from the upper line network is modulated in the base station device 1 and then output as an electrical signal for each frequency band from the output terminal. Then, it passes through a coaxial cable for downlink communication corresponding to the band, is branched by the distributor 6, and is output to the master station devices 4a and 4b.

The electrical signals are output to the radio unit 41 for each band via the downlink connector group 44 in the master station devices 4a and 4b. In the wireless unit 41, the electric signals in the respective bands are input to the synthesizer 411, synthesized, and output to the E / O unit 42.
The combined result of the electrical signals is converted into an optical signal by the E / O unit 42 and output to each of the slave station devices 5a and 5b through the optical fiber. Each of the slave station devices 5a and 5b converts the received optical signal into a radio signal and transmits it through the antenna.

In the upstream communication processing operation, the radio signal of the mobile communication system received by the antennas of the slave station devices 5a and 5b is converted into an optical signal and then output to the master station device 4a or 4b through the optical fiber.
In the master station device 4a or 4b, the optical signal is converted into an electric signal by the O / E unit 43-1 and output to the radio unit 41. The electrical signal is input to the distributor 412-1 in the wireless unit 41, distributed for each specified frequency band, and then output to the connector in the corresponding band of the uplink connector group 45-1.
Then, the electric signal passes through the upstream communication coaxial cable connected to the output destination connector, and is combined with the electric signal of the same band from the other master station device in the midway synthesizer 7, to the base station device 1. Is output. The base station device 1 demodulates the electrical signal for each band and transmits it as communication data to the upper line network.

  In general, the number of slave station devices that can be connected to the master station device is limited, and the number of slave station devices that can be connected is also determined by the number of master station devices provided in the system. Conventionally, when the number of slave station devices exceeding the number of connectable slave station devices is increased due to expansion of the communication area or the like, the master station device 4 is added, as shown in the optical transmission system of FIG. Using the distributor 6 and the combiner 7, the master station devices 4a and 4b need to be connected to the base station device 1 in parallel, and the slave station devices need to be connected to the master station devices 4a and 4b.

  In order to cope with such a connection method, the optical transmission system of FIG. 3 is provided with a distributor 6 on a coaxial cable for downlink communication, and an electric signal for each frequency band from the base station apparatus 1 is sent to a plurality of master station apparatuses. 4a and 4b, and a synthesizer 7 is provided on the coaxial cable for upstream communication so that electrical signals from the plurality of master station apparatuses 4a and 4b are combined and output to the base station apparatus 1. It was.

  However, in the system of FIG. 3, the transmission loss occurs in the electric signal when distributing in the distributor 6, so that the level of the electric signal is attenuated, and the same transmission is performed in the combining in the combiner 7. Loss occurs.

Here, consider a case where the base station apparatus 4b is added to a system in which the base station apparatus 1 and the parent station apparatus 4a are directly connected to construct the system shown in FIG. In this case, between the base station apparatus 1 and the master station apparatus 4a, the level of the electric signal is adjusted to be a preset level, and the base station apparatus 1 transmits the electric signal of the set level. The
Therefore, in order to connect the second master station apparatus to the base station apparatus 1 so as to have the configuration shown in FIG. 3, the base station apparatus 1 side in consideration of the transmission loss due to the distributor 6 and the combiner 7 It is necessary to readjust the level at the master station and the level at the master station.
In the readjustment of the above level, the output level of the base station apparatus 1 or the like is increased in downlink communication, and an electric signal of the level is transmitted to the master station apparatuses 4a and 4b, and output in the master station apparatuses 4a and 4b in uplink communication. You need to readjust the level. Therefore, in the readjustment of the level, it is necessary to readjust the level of the electric signal in both the uplink communication and the downlink communication.

  For this reason, it takes time to readjust the output level of the base station apparatus and the output level of the parent station apparatus, and the additional addition of the parent station apparatus is troublesome. For this reason, there is a problem that it is difficult to add a slave station device of a scale that must be increased by adding a master station device.

  The present invention has been made in view of the above circumstances, and enables the addition of a master station device without re-adjusting the output levels of the base station device and the master station device required in the conventional system. It is an object of the present invention to provide an optical transmission system capable of easily adding a slave station device of a scale that must be increased by adding station devices.

  The present invention for solving the problems of the above-mentioned conventional example combines an electrical signal of a plurality of bands from a base station device, converts it into an optical signal, transmits it to a plurality of slave station devices, and from a plurality of slave station devices Is an optical transmission system having a plurality of master station devices that receive the optical signal of the received signal, convert it into an electrical signal, distribute it to a plurality of bands, and transmit it to the base station device. A first synthesizer that synthesizes electrical signals in a plurality of bands, and the synthesized electrical signal is distributed to a plurality of electrical signals at the same level, and one of the distributed electrical signals is output to the master station device and distributed. A first distributor that outputs the other electrical signal to the outside of the master station device, and a plurality of slave station devices that convert the electrical signal output from the first distributor into the master station device into an optical signal The electrical / optical converter that transmits to the network and the optical signal received from the slave station device are converted into electrical signals. A second optical / electrical converter that combines the electrical signal converted by the optical / electrical converter within the master station and the electrical signal converted by the optical / electrical converter outside the master station. It is characterized by comprising a synthesizer and a second distributor for distributing the electrical signals synthesized by the second synthesizer to a plurality of bands.

  In the optical transmission system described above, the master station device directly connected to the base station device is a master master device, the master station device connected to the master master device is a slave master device, and the master master device Is connected to the base station apparatus so that the electric signal from the base station apparatus is output to the first combiner, and the distribution result in the second distributor is output to the base station apparatus. And a distribution result in the first distributor of the master base station device is output to the electrical / optical converter of the slave base station device, and includes at least an electrical / optical converter and an optical / electrical converter. The electrical signal from the optical / electrical conversion unit of the slave station device is connected to the master station device so as to be output to the second combiner of the master station device.

  According to the present invention, electrical signals of a plurality of bands are synthesized from a base station apparatus, converted into optical signals, transmitted to a plurality of slave station apparatuses, and received by receiving optical signals from the plurality of slave station apparatuses. An optical transmission system having a plurality of master station devices that convert the data into a plurality of bands and transmit to a plurality of bands to transmit to the base station device, wherein the master station device synthesizes the electrical signals of the plurality of bands from the base station device The first combiner and the combined electric signal are distributed to a plurality of electric signals of the same level, one of the distributed electric signals is output into the parent station device, and the other distributed electric signal is output to the parent station device A first distributor that outputs to the outside, and an electrical / optical converter that converts an electrical signal output from the first distributor into the master station device into an optical signal and transmits the optical signal to a plurality of slave station devices; An optical / electrical converter that receives an optical signal from a slave station device and converts it into an electrical signal, and the parent A second synthesizer that synthesizes the electrical signal converted by the optical / electrical conversion unit in the device and the electrical signal converted by the optical / electrical conversion unit outside the master station device, and the second synthesizer Since the optical transmission system includes a second distributor that distributes the combined electric signal to a plurality of bands, the level of the electric signal input to the base station apparatus and the level of the electric signal output from the base station apparatus is re-established. There is an effect that it is possible to easily add a slave station on a scale that cannot be accommodated without adding a master station device without adjustment.

  According to the present invention, a master station device that is directly connected to a base station device is a master master device, a master station device that is connected to the master master device is a slave master device, and the master master device is Are output to the first combiner, and the distribution result in the second distributor is connected to the base station apparatus so that the distribution result is output to the base station apparatus. And an optical / electrical conversion unit, and the distribution result in the first distributor of the master base station device is output to the electrical / optical conversion unit of the slave base station device, and the slave station device optical Since the optical transmission system is connected to the main master station apparatus so that the electrical signal from the electrical converter is output to the second combiner of the main master station apparatus, the electric signal input to the base station apparatus Without re-adjusting the signal and the level of the electrical signal output from the base station device. There is an effect that it is possible to easily perform the addition of the scale of the slave station apparatus can not cope unless they are in set.

Embodiments of the present invention will be described with reference to the drawings.
In the optical transmission system according to the embodiment of the present invention, a slave base station device having the same configuration is connected to a master master station device connected to a base station device. The electrical signals for each frequency band from the base station apparatus are synthesized, distributed and output to the slave station apparatus at the same level, and the slave station apparatus converts the distributed electrical signal into an optical signal, and the slave station apparatus Is output to the slave station device connected to. In uplink communication, in the slave station device, the optical signal from the slave station device connected to the slave station device is converted into an electrical signal and output to the master master station device. It is combined with the electrical signal from the slave station device connected to the device, distributed for each frequency band, and output to the base station device, whereby the electrical signal input to the base station device and the output from the base station device Therefore, it is possible to easily add a slave station device of a scale that cannot be dealt with without adding a master station device without re-adjusting the level of the electric signal.
Note that the main master station device in the claims corresponds to the master station device 2a of FIG. 2, and the slave master station device corresponds to the master station device 2b.

A configuration of an optical transmission system (hereinafter, this system) according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a network configuration diagram of this system, and FIG. 2 is a configuration block diagram of a master station device in this system.
The system shown in FIG. 1 performs two-way communication of electrical signals using a coaxial cable between a base station device 1 and a master station device 2a, and between the master station device 2a and a master station device 2b, and the master station device 2a and a slave station device. 3a-1 to 3a-m, providing two-way communication of optical signals using optical fibers between the master station device 2b and the slave station devices 3b-1 to 3b-n to provide a mobile communication service to a desired dead zone It can be done.

As shown in FIG. 1, this system includes a base station device 1 (BTS in the figure), master station devices 2a and 2b, and slave station devices 3a and 3b. In this system, the base station device 1 and the master station device 2a, the master station device 2a and the master station device 2b are connected by coaxial cables, respectively, and the master station device 2a and the slave station devices 3a-1 to 3a-m, The station apparatus 2b and the slave station apparatuses 3b-1 to 3b-n (m and n are integers of 2 or more) are respectively connected by optical fibers.
In the optical transmission system of FIG. 1, the base station device 1 and the master station devices 2a and 2b are centrally installed in a communication carrier station or the like, and the slave station devices 3a and 3b are installed in a dead zone to be communicated.

Next, the configuration of each part of the system will be described.
The base station device 1 is connected to an upper line network (not shown) and is connected to the master station device 2a by a coaxial cable. When receiving communication data for mobile communication transmitted from the circuit network in downlink communication, the base station apparatus 1 modulates the data and transmits the data as an electrical signal through a coaxial cable for each frequency band of mobile communication. Output to the device 2a.
Further, when the base station device 1 receives an electrical signal for each frequency band from the slave station device 3a or 3b through the coaxial cable from the master station device 2a in the upstream communication, the base station device 1 demodulates the electrical signal to transmit communication data, etc. Then, the communication data is transmitted to the upper circuit network.

The coaxial cable connecting the base station apparatus 1 and the master station apparatus 2a is provided for each communication direction and for each frequency band. FIG. 2 shows an example in which coaxial cables are provided one by one for each communication direction for the sake of simplicity.
As shown in FIG. 2, the coaxial cable for downlink communication has one end connected to the output terminal (RF_OUT in the figure) of the base station apparatus 1 and the other end connected to the connector of the downlink connector group 24 in the master station apparatus 2a. Connected. The coaxial cable for uplink communication has one end connected to the connector of the uplink connector group 25-1 or 25-2 in the master station device 2a and the other end connected to the input terminal (RF_IN in the figure) of the base station device 1. Connected.

  The master station device 2a (main master station device) performs two-way communication of mobile communication high-frequency electric signals with a coaxial cable with the base station device 1, and with the slave station devices 3a-1 to 3a-m. Two-way communication of optical signals using optical fibers. Specifically, in the downlink communication, the master station device 2a synthesizes high-frequency electrical signals for each frequency band transmitted from the base station device 1 through the coaxial cable, converts the signals into optical signals, and converts each of the slave station devices 3a. -1 ~ 3a-m is transmitted using optical fiber. In upstream communication, optical signals transmitted from the slave station devices 3a-1 to 3a-m through optical fibers are converted into high-frequency electrical signals, and are distributed for each frequency band, and a coaxial cable is connected to the base station device 1. Use to send.

  As described above, the master station device 2a is connected to the slave station devices 3a-1 to 3a-m by optical fibers in addition to being connected to the base station device 1 by a coaxial cable. Two optical fibers for connecting the master station device 2a and each of the slave station devices 3a-1 to 3a-m are provided in total, one upstream and one downstream for each slave station device.

  Furthermore, the master station device 2a is connected to the master station device 2b by a coaxial cable, and performs bidirectional communication of electrical signals with the master station device 2b using the cable. That is, the master station device 2a distributes the synthesis result of the electrical signals from the base station device 1 in the downlink communication, transmits the result of the synthesis to the master station device 2b through the coaxial cable, and from the master station device 2b in the uplink communication. After the output electrical signals from the slave station devices 3b-1 to 3b-n are combined with the electrical signals from the slave station devices 3a-1 to 3a-m, they are distributed according to frequency bands, and then the base station device 1 to send.

The master station device 2b (slave master station device) performs two-way communication of electrical signals of communication data of mobile communication using a coaxial cable with the master station device 2a, and the slave station devices 3b-1 to 3b-n. Bidirectional communication of optical signals using optical fibers. Specifically, the master station device 2b converts a high-frequency electrical signal transmitted from the master station device 2a through the coaxial cable into an optical signal in the downlink communication, and converts it into each slave station device 3b-1 to 3b-n. Transmit using optical fiber. In upstream communication, the optical signal transmitted from each of the slave station devices 3b-1 to 3b-n through the optical fiber is converted into an electrical signal and transmitted to the master station device 2a using a coaxial cable.
The configuration of the master station device 2b is the same as that of the master station device 2a.

As described above, the master station device 2b is connected to the slave station devices 3b-1 to 3b-n by optical fibers in addition to being connected to the master station device 2a by a coaxial cable. A total of two optical fibers for connecting the master station device 2b and each of the slave station devices 3b-1 to 3b-n are provided for each slave station device, one upstream and one downstream.
The configuration of each part of the master station devices 2a and 2b and the connection method between the master station device 2a and the master station device 2b will be described later.

The slave station devices 3a-1 to 3a-m perform two-way communication of optical signals of mobile communication data using optical fibers with the master station device 2a.
Each of the slave station devices 3a-1 to 3a-m includes an antenna. In uplink communication, the slave station devices 3a-1 to 3a-m convert a radio signal of communication data of the mobile communication system received by the antenna into an optical signal. Send to device 2a.
In downlink communication, an optical signal of communication data transmitted from the master station device 2a through an optical fiber is converted into a radio signal, and radio transmission is performed using an antenna.

The slave station devices 3b-1 to 3b-n perform bidirectional communication of optical signals of mobile communication data using optical fibers with the master station device 2b.
The configuration of slave station devices 3b-1 to 3b-n is the same as that of slave station devices 3a-1 to 3a-m, and the operation during communication is the same as that of slave station devices 3a-1 to 3a-m.

Next, the configuration of each unit of the master station devices 2a and 2b and the connection method of the master station device 2a and the master station device 2b will be described with reference to FIG.
As shown in FIG. 2, the master station device 2a includes a radio unit 21, an electrical / optical conversion unit (E / O unit in the figure, hereinafter referred to as this notation) 22, and an optical / electrical conversion unit (O / O in the figure). E section (this notation is used hereinafter) 23-1 and 23-2, downlink connector group 24, uplink connector groups 25-1 and 25-2, U links 26-1 to 26-3, U Link connector groups 27-1 to 27-3 are provided.
The radio unit 21 includes a downlink communication combiner 211, a downlink communication distributor 212, uplink communication distributors 213-1 and 213-2, an uplink communication combiner 214-1 and 214-2 and expansion connectors 215-1 to 215-3.

  Since the configuration of the master station device 2b is the same as that of the master station device 2a, description of the configuration of each unit is omitted. Further, the extension connector 215-1 of the radio unit 21 in the master station device 2a and the U-link connector group 27-3 in the master station device 2b, and the extension connector 215-2 of the radio unit 21 in the master station device 2a and the master station The U-link connector group 27-1 in the device 2b is connected to each other by a coaxial cable as shown by a broken line in FIG.

Here, the structure of each part which comprises the main | base station apparatus 2a is demonstrated.
In the downlink communication, the radio unit 21 combines the electric signals from the base station apparatus 1 output for each frequency band via the connectors of the downlink connector group 24 by the combiner 211, and distributes the combined electric signals to the distributor In addition to being output to the E / O conversion unit 22 via the U link 26-3, it is transmitted to the master station device 2b via the expansion connector 215-1 connected to the coaxial cable. In the wireless unit 21, the distributor 212 distributes and outputs the electric signals combined by the combiner 211 at the same level.

In addition, the radio unit 21 of the master station device 2a receives the electric power from the slave station devices 3a-1 to 3a-m output from the O / E unit 23-1 via the U link 26-1 in uplink communication. The signal and the electrical signal from the master station apparatus 2b input via the extension connector 215-2 are combined by the combiner 214-1 and further distributed by the frequency band by the distributor 213-1 to be a coaxial cable. Are transmitted to the base station apparatus 1 through the connectors of the connected uplink connector group 25-1.
In the wireless unit 21, the distributor 213 may be configured using, for example, a bandpass filter.

The E / O unit 22 of the master station device 2a is connected to the slave station devices 3a-1 to 3a-m via optical fibers, and converts the downstream communication electrical signal output from the radio unit 21 into an optical signal. The slave station devices 3a-1 to 3a-m are output through optical fibers.
The O / E units 23-1 and 23-2 of the master station device 2a are connected to the slave station devices 3a-1 to 3a-m via optical fibers and transmitted from the slave station devices 3a-1 to 3a-m. The upstream optical signal is converted into an electrical signal and output to the radio unit 21.

  The downlink connector group 24 is composed of a plurality of connectors for connecting coaxial cables, and is connected to the base station apparatus 1 through coaxial cables so that an electrical signal for downlink communication from the base station apparatus 1 can be transmitted. The data is output to the synthesizer 211 of the wireless unit 21. Each connector of the downlink connector group 24 is provided for each frequency band. In this system, a coaxial cable is prepared for each frequency band, and the base station apparatus 1 and each connector are connected by the cable. An electric signal for direction communication can be transmitted to the master station device 2a for each band.

The uplink connector group 25 is also composed of a plurality of connectors for connecting coaxial cables, and is connected to the base station apparatus 1 with coaxial cables, so that an electrical signal for uplink communication from the master station apparatus 2a can be transmitted. It can be transmitted to the base station apparatus 1.
Each connector of the uplink connector group 25 is also provided for each frequency band, and this system prepares a coaxial cable for each frequency band, and connects the base station apparatus 1 and each connector with the cable to An electric signal for direction communication can be transmitted to the base station apparatus 1 for each band.

The U link 26 is a U-shaped coaxial cable, and the U link connector group 27 has two connectors, and the corresponding U link 26 can be attached and detached.
In this system, when the master station device 2a is used as a single master master device or as a master master station device, the U link 26 is attached to the corresponding U link connector group 27 and used as an electrical signal path in the master station device 2a. .
On the other hand, when the master station device 2b is subordinately connected to the master station device 2a, the U link 26 in the master station device 2b is removed, the U link connector group 27 corresponding to the U link, and the master station device 2a. The expansion connector 215 is connected with a coaxial cable.

In the system shown in FIG. 2, the U link 26-3 in the master station device 2b is removed, and the expansion connector 215-1 in the master station device 2a and the U link connector group 27-3 in the master station device 2b are: A connector for direct connection to the E / O unit 22 is connected by a coaxial cable to form a downlink communication path.
In addition, the U link 26-1 in the master station device 2b is removed, and the O / E section 23− of the expansion connector 215-2 in the master station device 2a and the U link connector group 27-1 in the master station device 2b. An upstream communication path is formed by connecting the connector directly connected to 1 with a coaxial cable.

The extension connector 215 is a connector used to connect a coaxial cable to the U link connector group 27 of the connection destination master station device when adding the master station device. When the master station device is used as a single unit or a slave master station device, the expansion connector 215 is connected to a terminator (not shown) and the master station device 2a subordinate to the master station device 2b. In this case, the terminator is removed from the master station device 2a.
In the system of FIG. 2, the expansion connector 215-1 of the master station device 2a is an output terminal of the distributor 212 in the radio unit 21, and when connected to the master station device 2b, it is downloaded to the master station device 2b. It becomes the output destination of the electric signal of direction communication.
Further, the expansion connectors 215-2 and 215-3 of the master station device 2a are input terminals to the combiners 214-1 and 214-2 in the radio unit 21, respectively, and are connected when connected to the master station device 2b. This becomes the input source of the electrical signal for uplink communication from the master station device 2b.

  In the master station devices 2a and 2b of this system, signal processing for downlink communication is performed by the downlink connector group 24, the combiner 211, the distributor 212, and the E / O unit 22 (hereinafter referred to as downlink communication processing sequence). The signal processing for uplink communication is performed by the O / E unit 23, the combiner 214, the distributor 213, and the uplink connector group 25 (hereinafter referred to as uplink communication processing sequence).

In addition, the master station devices 2a and 2b of this system are provided with two upstream communication processing sequences. This is because the base station device 1 is divided into a plurality of sequences in consideration of fading effects in wireless communication. This is to cope with a case where a diversity system that handles a signal having a high reception level as the regular communication data among the processed upstream signals is adopted. Here, the base station apparatus 1 does not employ a diversity system, and the master station apparatuses 2a and 2b are configured by an O / E unit 23-1, a combiner 214-1, a distributor 213-1 and an uplink connector group 25. The description will be made on the assumption that -1 is used for the upstream communication processing sequence.
Therefore, although not shown in FIG. 2, the master station device 2a is connected to each slave station device 3a-1 to 3a-m by the E / O unit 22 and the O / E unit 23-1 via an optical fiber. The station device 2b is connected to each of the slave station devices 3b-1 to 3b-n by the E / O unit 22 and the O / E unit 23-1 through an optical fiber.

Next, processing operations during communication of this system will be described with reference to FIGS. 1 and 2 for each communication direction.
First, the processing operation of the downlink communication will be described.
In FIG. 1, communication data from the higher-level network is modulated by the base station apparatus 1 and then output as a high-frequency electrical signal for each frequency band from the output terminal.
The electrical signal for each frequency band is output to the master station device 2a through a coaxial cable for downlink communication corresponding to the band.

In FIG. 2, the band-specific electrical signals input to the master station device 2 a are output to the radio unit 21 via the connectors of the downlink connector group 24. In the wireless unit 21, the electric signals of the respective bands are input to the combiner 211 and combined, and the combined level is distributed to two systems by the distributor 212, and is supplied to the E / O unit 22 and the expansion connector 215-1. Distributed and output.
The electric signal distributed and output to the E / O unit 22 is converted into an optical signal and output to each of the slave station devices 3a-1 to 3a-m through an optical fiber for downstream communication. Each of the slave station devices 3a-1 to 3a-m converts the received optical signal into a radio signal and wirelessly transmits it to an area covered by each of the slave station devices through an antenna.

The electrical signal distributed and output to the extension connector 215-1 passes through the coaxial cable and is directly connected to the E / O unit 22 in the U-link extension connector group 27-3 in the master station device 2b that is the connection destination. Output to the connector.
The electrical signal input to the master station device 2b via the connector is converted into an optical signal in the E / O unit 22, and is output to each slave station device 3b-1 to 3b-n through an optical fiber for downstream communication. Each of the slave station devices 3b-1 to 3b-n converts the received optical signal into a radio signal and wirelessly transmits it to an area covered by each of the slave station devices through an antenna. The above is the processing operation of the downlink communication in this system.

Next, the upstream communication processing operation in this system will be described.
In FIG. 1, the radio signal of the mobile communication system received by the antennas of the slave station devices 3a-1 to 3a-m is converted into an optical signal and then output to the master station device 2a through an optical fiber.
The optical signal input to the master station device 2a is converted into an electric signal by the O / E unit 23-1 and output to the radio unit 21 as shown in FIG. The electric signal is input to the combiner 214-1 via the U link 26-1 in the wireless unit 21.

Returning to FIG. 1, the radio signal of the mobile communication system received by the antenna of each of the slave station devices 3b-1 to 3b-n is converted into an optical signal and then output to the master station device 2b through the optical fiber. The
The optical signal input to the master station device 2b is converted into an electrical signal by the O / E unit 23-1 and output to the radio unit 21 as shown in FIG. The electrical signal is transmitted through the coaxial cable through the connector directly connected to the O / E unit 23-1 in the U-link expansion connector group 27-1 in the radio unit 21, and the expansion connector 215- in the master station device 2a. Output to 2. The electrical signal input to the master station device 2a is further input to the combiner 214-1 in the radio unit 21.

The electrical signals from the slave station devices 3a-1 to 3a-m and the electrical signals input from the slave station devices 3b-1 to 3b-n via the master station device 2b are combined with the master station device 2a. The data are combined in the output device 214-1 and output to the distributor 213-1.
The result of combining the electrical signals in the combiner 214-1 is distributed for each frequency band in the distributor 213-1 and is output to the corresponding band connector in the uplink connector group 25-1.
The distributed electrical signal is output to the base station apparatus 1 through a coaxial cable for uplink communication connected to the output destination connector. The base station apparatus 1 demodulates the electrical signal for each band and transmits it as communication data to the upper line network through the line network. The above is the processing operation of uplink communication in this system.

As described in the prior art, in the conventional general optical transmission system shown in FIG. 3, the base station device 1 and the master station devices 4a and 4b are connected in parallel with a coaxial cable. The electric signal in the same frequency band from the base station apparatus 1 is distributed to the master station apparatuses 4a and 4b by the distributor 6, and in uplink communication, the electric signals in the same frequency band from the slave station apparatuses 4a and 4b are synthesized. It was synthesized by the device 7.
For this reason, considering the case where only the master station device 4a is connected to the base station device 1 and the master station device 4b is newly added to the system in which the level of the electric signal is adjusted between the devices, the distributor 6 and the combiner There is a problem that the input level of the master station device 4a and the input level to the base station device 1 are lowered due to the device 7 and cable loss. In order to cope with this, the conventional optical transmission system has to adjust the output level of the base station apparatus 1 and the output levels of the master station apparatuses 4a and 4b again.

  This system does not distribute and synthesize electrical signals on the coaxial cable connecting the base station device 1 and the master station device 2a. In downlink communication, the radio unit 21 of the master station device 2a uses the synthesizer 211 to The electric signals having different frequency bands from the station device 1 are combined, and the combined electric signal is distributed to the E / O conversion unit 22 and the E / O unit 22 of the master station device 2b by the distributor 212 at the same level. Output.

  In the uplink communication, in the uplink communication, the radio unit 21 of the master station device 2a receives the electrical signal from the slave station device 3b including a plurality of frequency components and the slave station device 3a including a plurality of frequency components. Are combined by the combiner 214, and the combined electric signal is distributed by the frequency divider 213 for each frequency band and output to the base station apparatus 1.

  Therefore, in this system, the radio unit 21 of the master station device 2a distributes the electrical signals to the slave station devices 3a and 3b in the downlink communication and combines the electrical signals from the slave station devices 3a and 3b in the uplink communication. Therefore, when the master station device 2b is additionally added, the master station device 2b is subordinated to the master station device 2a and cascaded without adjusting the output level of the base station device 1 or the master station device 2a again. Since the slave station devices can be added with a simple configuration to be connected, the communication area can be easily expanded.

  In this system, when the base station apparatus 1 adopts the diversity method, the O / O of the connectors of the extension connector 215-3 in the master station apparatus 2a and the U-link connector group 27-2 in the master station apparatus 2b is used. It is necessary to connect the connector directly connected to the E section 23-2 with a coaxial cable so that an electric signal is output from the two upstream communication processing sequences in the master station device 2a to the base station device 1.

The master station device 2a of this system performs bidirectional communication of electrical signals of a plurality of different frequency bands with the base station device 1, but performs bidirectional communication of electrical signals of the same frequency band. May be.
As a specific example of bidirectional communication using electrical signals in the same frequency band, the master station device 2a handles electrical signals in the same frequency band, but is connected to a plurality of base station devices with different operators, and in downlink communication, The electric signals from the base station devices are combined by the combiner 211 of the radio unit 21 and the combined electric signals are combined at the same level to the E / O unit 22 of the master station device 2a and the master station device 2b by the distributor 212. Distribute and output.

Further, in uplink communication, the master station device 2a combines the electrical signals from the slave station devices 3a and 3b including a plurality of frequency components by the combiner 214 of the radio unit 21 and each distributor 213 The combined electrical signal is distributed to the station apparatus in the same frequency band handled by each base station apparatus and output. That is, in uplink communication, distributor 213 extracts and outputs components in the same frequency band handled by each base station device from the combined electrical signal including a plurality of frequency components. The distributor 213 may be configured using, for example, a band pass filter.
The system may adopt a CDMA (Code Division Multiple Access) communication system or a TDMA (Time Division Multiple Access) communication system when handling electrical signals in the same frequency band. .

  As described above, according to the optical transmission system according to the embodiment of the present invention, the master station device 2b having the same configuration is connected to the master station device 2a connected to the base station device 1, and downlink communication is performed. Then, in the radio unit 21 of the master station device 2a, the electrical signals for each frequency band from the base station device 1 are combined, distributed to the E / O unit 22 and the master station device 2b at the same level, and output, In addition to outputting to the slave station device 3a via the E / O unit 22, the master station device 2b converts the distributed electrical signal into an optical signal and outputs it to the slave station device 3b connected to the master station device 2b. In uplink communication, the master station device 2b converts the optical signal from the slave station device 3b into an electrical signal and outputs the electrical signal to the master station device 2a. The radio unit 21 of the master station device 2a uses the master station device 2a. Combined with the electrical signal from the slave station device 3a connected to the By distributing to each frequency band and outputting to the base station device, it is possible to add a master station device without re-adjusting the output level of the base station device and the master station device required in the conventional system Thus, there is an effect that it is possible to easily add a slave station device of a scale that must be provided by adding a master station device.

  The present invention is an optical transmission system for covering a dead zone of mobile communication, which enables the addition of a slave station device without re-adjusting the output levels of the base station device and the master master station device. It is possible to easily increase the number of slave station devices that must be increased by adding station devices.

1 is a network configuration diagram of an optical transmission system according to an embodiment of the present invention. FIG. It is a block diagram of the configuration of the master station device in the optical transmission system according to the embodiment of the present invention. It is a configuration block diagram of a conventional general optical transmission system in which two master station devices are connected to a base station device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Base station apparatus, 2a, 2b, 4a, 4b ... Master station apparatus, 3a, 3b, 5a, 5b ... Slave station apparatus, 6 ... Distributor, 7 ... Synthesizer, 21, 41 ... Radio | wireless part, 22, 42 ... Electric / optical conversion part, 23,43 ... Optical / electrical conversion part, 24,44 ... Downlink connector group, 25,45 ... Uplink connector group, 26 ... U link, 27 ... U link connector group

Claims (2)

A base station device combines electrical signals of a plurality of bands, converts them into optical signals, transmits them to a plurality of slave station devices, receives optical signals from a plurality of slave station devices, converts them into electrical signals, An optical transmission system having a plurality of master station devices that are distributed to a band and transmitted to a base station device,
The master station device includes a first combiner that combines electrical signals of a plurality of bands from the base station device;
The synthesized electric signal is distributed to a plurality of electric signals of the same level, one distributed electric signal is output into the master station apparatus, and the other distributed electric signal is output outside the master station apparatus. A distributor of
An electrical / optical converter that converts an electrical signal output from the first distributor into the master station device into an optical signal and transmits the optical signal to a plurality of slave station devices;
An optical / electrical converter that receives an optical signal from the slave station device and converts it into an electrical signal;
A second combiner that forms if the electric signal converted by the optical / electrical conversion of the electrical signals and the master station outside converted by the optical / electrical converter of the parent station,
An optical transmission system comprising: a second distributor that distributes the electric signal combined by the second combiner to a plurality of bands. A master station device directly connected to the base station device is a master master device, a master station device connected to the master master device is a slave master device,
The main master station apparatus outputs the electric signal from the base station apparatus to the first combiner, and the distribution result in the second distributor is output to the base station apparatus so as to be output to the base station apparatus. Connected,
The slave station device includes at least an electrical / optical conversion unit and an optical / electrical conversion unit, and a distribution result in the first distributor of the primary master station device is an electrical / optical conversion of the slave station device. And the electrical signal from the optical / electrical converter of the slave station device is connected to the master station device so that the electrical signal is output to the second combiner of the master station device. The optical transmission system according to claim 1.

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