JP2019153945A - Optical radio converter, wraparound signal remover, communication network, and wraparound signal removing method - Google Patents

Abstract

To prevent deterioration in signal quality due to a wraparound radio signal or wraparound optical fiber radio signal in a communication network that connects a plurality of radio terminals by using RoF.SOLUTION: An optical radio converter according to the present disclosure is connected with another optical radio converter via an optical fiber transmission path. The optical radio converter includes: an antenna unit that transmits and receives radio signals to/from a radio terminal; an optical radio conversion unit that converts the radio signal received by the antenna unit into an optical fiber radio signal to output it to the optical fiber transmission path, and converts an optical fiber radio signal transmitted on the optical fiber transmission path into a radio signal to output it to the antenna unit; and a first wraparound signal suppression circuit that branches the radio signal output from the optical radio conversion unit to the antenna unit, generates a first suppression signal for suppressing a wraparound radio signal which is a radio signal received by the antenna unit by using the branched-off radio signal, and integrates the first suppression signal into the wraparound radio signal.SELECTED DRAWING: Figure 5

Description

  The present disclosure relates to a communication device and a communication network for enabling wireless terminals outside the wireless propagation distance range to perform communication in wireless communication.

  When wireless terminals communicate with other wireless terminals wirelessly, wireless terminals must establish wireless communication only when the wireless terminals exist within the wireless propagation distance range in which the wireless signal used for communication can be reached. (For example, refer nonpatent literature 1).

  When wireless terminals exist outside the wireless propagation distance range, each wireless terminal is connected to a wireless parent device installed within each wireless propagation distance range, and the wireless parent devices are connected by a network switch or a network router. Communication can be established by adopting a configuration in which a connection is made to the opposite wireless master unit via the configured relay network. Alternatively, each wireless terminal can be connected to a wireless relay installed within each wireless propagation distance range, and the wireless relay can establish wireless communication with each other, thereby establishing communication between wireless terminals. It is.

FIG. 1 is an example of a form in which wireless terminals are connected via a relay network.
The communication network shown in FIG. 1 includes wireless terminals 111 and 112, wireless master devices 121 and 122, and a relay network 151. The wireless master device 121 includes an antenna unit 131 and a transmission function unit 141. The wireless master device 122 includes an antenna unit 132 and a transmission function unit 142.

  At this time, the wireless terminal 111 is wirelessly connected to the antenna unit 131 of the wireless parent device 121, and the wireless parent device 121 is connected to the wireless parent device 122 from the transmission function unit 141 via the relay network 151 by the transmission function unit 142. The antenna unit 132 of the base unit 122 is wirelessly connected to the wireless terminal 112. The relay network 151 is generally configured using a plurality of network switches and network routers.

FIG. 2 is an example of a form in which wireless terminals are connected via a wireless repeater.
The communication network shown in FIG. 2 includes wireless terminals 211 and 212 and wireless relay devices 221, 222, and 223. The wireless repeater 221 includes antenna units 231 and 232 and a transmission function unit 241. The wireless repeater 222 includes antenna units 233 and 234 and a transmission function unit 242. The wireless repeater 223 includes antenna units 235 and 236 and a transmission function unit 243.

  At this time, the wireless terminal 211 is wirelessly connected to the antenna unit 231 of the wireless relay device 221, the wireless relay devices 221 and 222 are wirelessly connected to each other by the antenna units 232 and 233, and the wireless relay devices 222 and 223 are respectively connected to each other. Are wirelessly connected to each other, and the antenna unit 236 of the wireless repeater 223 is wirelessly connected to the wireless terminal 212. The antenna units 231 and 232 constituting the wireless repeater 221 are connected via the transmission function unit 241, and the antenna units 233 and 234 constituting the wireless repeater 222 are connected via the transmission function unit 242, and wireless relaying The antenna units 235 and 236 constituting the device 223 are connected via the transmission function unit 243.

  FIG. 2 shows an example in which three wireless repeaters are connected. However, the configuration is not limited to three wireless repeaters, and even in the configuration of one wireless repeater, two or more multiple repeaters Even in the configuration, it is possible to establish communication in any case, and it is possible to perform communication of a long-distance wireless terminal as the number of wireless relay devices increases.

  However, in the form in which wireless terminals as shown in FIG. 1 are connected via a relay network, a plurality of network switches and network routers are required to configure the relay network, and the network configuration is complicated.

  In the form in which the wireless terminals as shown in FIG. 2 are connected via a wireless relay device, when the distance between the wireless terminals is a long distance, it is necessary to establish communication via a plurality of wireless relay devices. To be complicated. In order to avoid complication, when it comprises a small number of radio repeaters, the communication distance between radio terminals will be limited.

  Furthermore, since the devices and wireless relay devices that make up the relay network need to be set, controlled, and maintained, a mechanism for device management must be separately configured. At this time, as a means for easily transmitting a radio signal over a long distance, there is a RoF (Radio over Fiber) technique for transmitting and receiving a radio signal via a low-loss, alternative optical fiber transmission line (for example, non-patent literature). 2).

FIG. 3 is an example of a form in which wireless terminals are connected using RoF technology.
The communication network shown in FIG. 3 includes wireless terminals 311 and 312, optical wireless converters 321 and 322, and an optical fiber transmission line 361. The optical wireless converter 321 includes an antenna unit 341 including a transmission antenna 331 and a reception antenna 332, and an optical wireless conversion unit 351. The optical wireless converter 322 includes an antenna unit 342 including a transmitting antenna 333 and a receiving antenna 334, and an optical wireless converter 352.

  At this time, the wireless terminal 311 is wirelessly connected to the antenna unit 341 of the optical to wireless converter 321, and the optical to wireless converter 321 performs optical to wireless conversion from the optical to wireless converter 351 through the optical fiber transmission path 361 by the optical to wireless converter 352. The antenna unit 342 of the optical wireless converter 322 is wirelessly connected to the wireless terminal 312.

  In the configuration of the communication network, the optical wireless converters 321 and 322 can directly convert the wireless signals transmitted from the wireless terminals 311 and 312 into optical fiber wireless signals in which the optical signals are modulated with the wireless signals, respectively. It is. Further, the optical wireless converters 321 and 322 do not require a transmission function unit for connection to the relay network.

  As a result, it is possible to connect directly using only an optical fiber transmission line without using a network switch or a network router used in a relay network, and the configuration of the optical wireless converter itself can be simplified. is there.

IEICE Knowledge Base Knowledge Forest (http://www.ieice-hbkb.org/portal/), 4 groups Mobile / Wireless, 1 Radio Communication Basics, 2 Radio Propagation Paths, 9 Radio Channel Design Reference Ver. 1 2010.10.1.9 Hiroyo Ogawa, “Microwave and Millimeter-Wave Fiber Optical Technologies for Subcarrier Transmission Systems,” IEICE Transactions on Communions. E76-B, no. 9, pp. 1078-1090, September 1993.

  However, in the form of the communication network as shown in FIG. 3, the problem shown in FIG. 4 occurs.

  In FIG. 4, the radio signal 411 transmitted from the radio terminal 311 is received by the receiving antenna 332, and is transmitted through the optical fiber transmission path 361 as an optical fiber radio signal 412 by the optical radio conversion unit 351. The optical fiber radio signal 412 is converted into a radio signal 413 by the optical radio conversion unit 352 and transmitted to the radio terminal 312 from the transmission antenna 333, but the radio signal 413 is received by the reception antenna 334 and wraps around by the optical radio conversion unit 352. An optical fiber radio signal 414 is transmitted through the optical fiber transmission line 361. The wraparound optical fiber wireless signal 414 is transmitted to the wireless terminal 311 from the transmission antenna 331 as a wraparound wireless signal 415 by the optical wireless conversion unit 351.

  The wireless signal 421 transmitted from the wireless terminal 312 is received by the receiving antenna 334 and transmitted through the optical fiber transmission line 361 as an optical fiber wireless signal 422 by the optical wireless conversion unit 352. The optical fiber wireless signal 422 is converted into a wireless signal 423 by the optical wireless conversion unit 351 and transmitted from the transmission antenna 331 to the wireless terminal 311. An optical fiber radio signal 424 is transmitted through the optical fiber transmission line 361. The wraparound optical fiber radio signal 424 is transmitted to the wireless terminal 312 from the transmission antenna 333 as a wraparound radio signal 425 by the optical wireless conversion unit 352.

  The wireless terminal 312 receives the wraparound wireless signal 425 transmitted from the wireless terminal 312 in addition to the wireless signal 413 transmitted from the wireless terminal 311. The wireless terminal 311 receives the sneaking wireless signal 415 transmitted from the wireless terminal 311 in addition to the wireless signal 423 transmitted from the wireless terminal 312. As a result, unnecessary radio signals 425 and 415 are received at the same time as the respective desired radio signals 413 and 423 are received, and the signal quality deteriorates. When the signal quality deteriorates, there arises a disadvantage that the radio propagation range becomes small and the transmission band becomes small. In the worst case, it becomes impossible to establish communication.

  Therefore, an object of the present disclosure is to prevent signal quality degradation due to a sneak radio signal or a sneak optical fiber radio signal in a communication network in which a plurality of radio terminals are connected using RoF.

  According to the present disclosure, in a communication network that connects a plurality of wireless terminals using RoF, a circuit or a device that suppresses a sneak radio signal or a sneak optical fiber radio signal is provided.

The optical wireless converter according to the present disclosure is:
An optical wireless converter connected to another optical wireless converter via an optical fiber transmission line,
An antenna unit for transmitting and receiving radio signals to and from a wireless terminal;
A radio signal received by the antenna unit is converted into an optical fiber radio signal and output to the optical fiber transmission line, and an optical fiber radio signal transmitted through the optical fiber transmission line is converted into a radio signal to be transmitted to the antenna unit. An optical wireless conversion unit for output;
The wireless signal output from the optical wireless conversion unit to the antenna unit is branched, and the branched wireless signal is used as the first suppression signal for suppressing the sneak radio signal received by the antenna unit. A first sneak signal suppression circuit that generates and synthesizes the first suppression signal with the sneak radio signal;
Is provided.

The optical wireless converter according to the present disclosure is:
An optical wireless converter connected to another optical wireless converter via an optical fiber transmission line,
An antenna unit for transmitting and receiving radio signals to and from a wireless terminal;
A radio signal received by the antenna unit is converted into an optical fiber radio signal and output to the optical fiber transmission line, and an optical fiber radio signal transmitted through the optical fiber transmission line is converted into a radio signal to be transmitted to the antenna unit. An optical wireless conversion unit for output;
A second suppression unit that branches a radio signal output from the antenna unit to the optical wireless conversion unit and suppresses a sneak optical fiber radio signal received by the antenna unit included in the other optical wireless converter; A second sneak signal suppression circuit that generates a signal using the branched radio signal and synthesizes the second suppression signal with the sneak optical fiber radio signal;
Is provided.

The optical wireless converter according to the present disclosure is:
An optical wireless converter connected to another optical wireless converter via an optical fiber transmission line,
An antenna unit for transmitting and receiving radio signals to and from a wireless terminal;
A radio signal received by the antenna unit is converted into an optical fiber radio signal and output to the optical fiber transmission line, and an optical fiber radio signal transmitted through the optical fiber transmission line is converted into a radio signal to be transmitted to the antenna unit. An optical wireless conversion unit for output;
The wireless signal output from the optical wireless conversion unit to the antenna unit is branched, and the branched wireless signal is used as the first suppression signal for suppressing the sneak radio signal received by the antenna unit. A first sneak signal suppression circuit that generates and synthesizes the first suppression signal with the sneak radio signal;
A second suppression unit that branches a radio signal output from the antenna unit to the optical wireless conversion unit and suppresses a sneak optical fiber radio signal received by the antenna unit included in the other optical wireless converter; A second sneak signal suppression circuit that generates a signal using the branched radio signal and synthesizes the second suppression signal with the sneak optical fiber radio signal;
Is provided.

The wraparound signal removal machine according to the present disclosure is:
A sneak signal remover disposed in the optical fiber transmission line of a communication network in which a plurality of optical wireless converters that convert a radio signal and an optical fiber radio signal to each other are connected by an optical fiber transmission line,
The optical fiber radio signal transmitted by the first optical fiber provided in the optical fiber transmission line is converted into a radio signal, the radio signal converted by the second signal converter is converted into an optical fiber radio signal, and the first A first signal converter that outputs to one optical fiber;
An optical fiber radio signal transmitted through a second optical fiber provided in the optical fiber transmission line is converted into a radio signal, a radio signal converted by the first signal converter is converted into an optical fiber radio signal, and A second signal converter for outputting to the second optical fiber;
A first sneak optical fiber that branches the radio signal converted by the first signal conversion unit, and that the radio signal is received by an antenna unit provided in an optical radio converter connected to the second optical fiber. A third suppression signal for suppressing the radio signal is generated using the branched radio signal, the third suppression signal is synthesized with the first wraparound optical fiber radio signal, and the second signal conversion unit The wireless signal converted in step 4 is branched, and the wireless signal is suppressed by the second wraparound optical fiber wireless signal received by the antenna unit provided in the optical wireless converter connected to the first optical fiber. A bi-directional sneak signal suppression circuit that generates the suppression signal using the branched radio signal and synthesizes the fourth suppression signal with the second sneak optical fiber radio signal;
Is provided.

The communication network according to the present disclosure is:
A communication network in which a plurality of optical wireless converters that convert a wireless signal and an optical fiber wireless signal to each other are connected by an optical fiber transmission line,
The optical wireless converter according to the present disclosure is used for at least one of the plurality of optical wireless converters.

The communication network according to the present disclosure is:
A communication network in which a plurality of optical wireless converters that convert a wireless signal and an optical fiber wireless signal to each other are connected by an optical fiber transmission line,
A wraparound signal removal machine according to the present disclosure is disposed in the optical fiber transmission line.

A wraparound signal elimination method according to the present disclosure includes:
A wraparound signal removal method executed by a communication network in which a plurality of optical to wireless converters that convert a radio signal and an optical fiber radio signal to each other are connected by an optical fiber transmission line,
The optical wireless converter is
An antenna unit for transmitting and receiving radio signals to and from a wireless terminal;
A radio signal received by the antenna unit is converted into an optical fiber radio signal and output to the optical fiber transmission line, and an optical fiber radio signal transmitted through the optical fiber transmission line is converted into a radio signal to be transmitted to the antenna unit. An optical wireless conversion unit for output;
With
A first sneak signal suppression circuit divides a radio signal output from the optical wireless conversion unit to the antenna unit, and the first suppression signal suppresses the sneak radio signal received by the antenna unit. Is generated using the branched radio signal, and the first sneak signal suppression procedure for combining the first suppression signal with the sneak radio signal, or
A second sneak signal suppression circuit branches a radio signal output from the antenna unit to the optical to radio conversion unit, and the sneak optical fiber received by the antenna unit provided in the other optical to radio converter A second sneak signal suppression procedure for generating a second suppression signal for suppressing the radio signal by using the branched radio signal and combining the second suppression signal with the sneak optical fiber radio signal;
Have

A wraparound signal elimination method according to the present disclosure includes:
A wraparound signal removal method executed by a communication network in which a plurality of optical to wireless converters that convert a radio signal and an optical fiber radio signal to each other are connected by an optical fiber transmission line,
The communication network is
The optical fiber radio signal transmitted by the first optical fiber provided in the optical fiber transmission line is converted into a radio signal, the radio signal converted by the second signal converter is converted into an optical fiber radio signal, and the first A first signal converter that outputs to one optical fiber;
An optical fiber radio signal transmitted through a second optical fiber provided in the optical fiber transmission line is converted into a radio signal, a radio signal converted by the first signal converter is converted into an optical fiber radio signal, and A second signal converter for outputting to the second optical fiber;
With
A bidirectional sneak signal suppression circuit branches the radio signal converted by the first signal conversion unit, and the radio signal is received by an antenna unit provided in an optical radio converter connected to the second optical fiber. A third suppression signal that suppresses the generated first wraparound optical fiber radio signal is generated using the branched radio signal, and the third suppression signal is combined with the first wraparound optical fiber radio signal. Procedure or
A bidirectional sneak signal suppression circuit branches the radio signal converted by the second signal conversion unit, and the radio signal is received by an antenna unit provided in an optical radio converter connected to the first optical fiber. A fourth suppression signal that suppresses the generated second wraparound optical fiber radio signal is generated using the branched radio signal, and the fourth suppression signal is combined with the second wraparound optical fiber radio signal. Bidirectional sneak signal suppression procedure,
Have

  The above disclosures can be combined as much as possible.

  The present disclosure provides a communication device and a communication network for establishing communication without using a complicated relay network or a plurality of wireless relay devices when wireless terminals outside the wireless propagation distance range communicate with each other. Can be provided.

It is an example of the form by which a wireless terminal is connected via a relay network. It is an example of the form by which a wireless terminal is connected via a wireless repeater. It is an example of the form by which a wireless terminal is connected using RoF technology. It is an example of the subject which arises with the form of a communication network like FIG. It is a figure which shows the 1st example of the communication network in this indication. The 1st structural example of a cancellation circuit is shown. 2 shows a second configuration example of a cancel circuit. FIG. 6 is a first explanatory diagram showing signal propagation and transmission in the communication network shown in FIG. 5. FIG. 6 is a second explanatory diagram showing signal propagation and transmission in the communication network shown in FIG. 5. It is a figure which shows the 2nd example of the communication network in this indication. It is explanatory drawing shown about the propagation and transmission of a signal in the communication network shown in FIG. It is a figure which shows the 3rd example of the communication network in this indication. It is a figure which shows the 4th example of the communication network in this indication. It is a figure which shows the 5th example of the communication network in this indication. It is a figure which shows the 6th example of the communication network in this indication. It is a figure which shows the 7th example of the communication network in this indication. It is a figure which shows the 8th example of the communication network in this indication. It is a figure which shows the 9th example of the communication network in this indication.

  Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In addition, this indication is not limited to embodiment shown below. These embodiments are merely examples, and the present disclosure can be implemented in various modifications and improvements based on the knowledge of those skilled in the art. In the present specification and drawings, the same reference numerals denote the same components.

(First embodiment)
FIG. 5 is a diagram illustrating a first example of a communication network in the present disclosure for solving the problem illustrated in FIG. 4.

  The communication network shown in FIG. 5 includes wireless terminals 511 and 512, optical wireless converters 521 and 522, and an optical fiber transmission line 571. The optical wireless converter 521 includes an antenna unit 541 including a transmission antenna 531 and a reception antenna 532, a cancel circuit 551, and an optical wireless conversion unit 561. The optical wireless converter 522 includes an antenna unit 542 including a transmission antenna 533 and a reception antenna 534, a cancel circuit 552, and an optical wireless conversion unit 562.

  At this time, the wireless terminal 511 is wirelessly connected to the antenna unit 541 of the optical wireless converter 521, and the optical wireless converter 521 performs optical wireless conversion from the optical wireless converter 561 via the optical fiber transmission line 571 by the optical wireless converter 562. The antenna unit 542 of the optical wireless converter 522 is wirelessly connected to the wireless terminal 512.

  The optical wireless conversion units 561 and 562 have a function of mutually converting a radio signal and an optical fiber radio signal. For example, the optical wireless conversion unit 561 converts the wireless signal received by the reception antenna 532 into an optical fiber wireless signal and outputs the optical fiber transmission signal to the optical fiber transmission line 571. The optical wireless conversion unit 561 converts the optical fiber wireless signal transmitted through the optical fiber transmission path 571 into a wireless signal and outputs the wireless signal to the antenna unit 541. Accordingly, the optical wireless converters 521 and 522 of the present disclosure transmit a wireless signal by RoF.

  Optical wireless conversion units 561 and 562 may employ any configuration that modulates an optical fiber wireless signal with the wireless signals received by receiving antennas 532 and 534 and extracts the wireless signal that is modulating the optical fiber wireless signal. The optical wireless conversion units 561 and 562 can be configured by combining, for example, an optical transmitter using a laser diode and an optical receiver using a photodetector. Further, in order to improve communication quality, a configuration may be used in which some or all of an optical external modulator, a signal amplifier that amplifies a radio signal to a desired intensity, and a bandpass filter that extracts a desired band of a radio signal are used. .

  The cancel circuit 551 is connected to the antenna unit 541 and the optical wireless conversion unit 561 inside the optical wireless converter 521. The cancel circuit 552 is connected to the antenna unit 542 and the optical wireless converter 562 inside the optical wireless converter 522. The cancel circuits 551 and 552 function as a sneak signal suppression circuit according to the present disclosure, and can be configured as shown in FIG. 6 or FIG. 7, for example.

  The cancel circuit shown in FIG. 6 includes a branching unit 611, a delay unit 621, an attenuator 631, and a combiner 641. Radio signals 651 and 661 and a sneak radio signal 654 of the radio signal 651 are input to the cancel circuit, and the radio signals 652 and 662 are output from the cancel circuit.

  The wireless signal 651 input to the cancellation circuit is branched into wireless signals 652 and 653 by the branching unit 611, and the wireless signal 652 is output from the cancellation circuit. The radio signal 653 is given a desired delay and attenuation so as to be a signal having a phase opposite to that of the wraparound radio signal 654 by the delay unit 621 and the attenuator 631, and becomes a suppression signal. The radio signal 653 that has become the suppression signal is synthesized by the synthesizer 641 with the radio signal 661 and the sneak radio signal 654 input to the cancel circuit. Since the radio signal 653 and the sneak radio signal 654 are controlled by the delay unit 621 and the attenuator 631 so as to have the opposite phase relationship with the same intensity, when they are synthesized by the synthesizer 641, they cancel each other, and as a result, the radio signal 661 is output as a radio signal 662 as it is.

  Note that the generation method of the suppression signal is not limited to the method using the delay unit and the attenuator, and any method that can generate a signal having the same intensity as the wraparound radio signal 654 by using the radio signal 653 can be adopted. be able to. The signal strength of the suppression signal is not limited to the same as that of the sneak radio signal 654, and may be any strength that the sneak radio signal 654 can suppress.

  At this time, as shown in FIG. 7, by using a plurality of delay units and attenuators, for example, in addition to the sneak radio signal in which the radio signal output from the transmission antenna is directly received by the reception antenna, walls, obstacles, etc. It is also possible to remove a sneak radio signal in a multipath environment that is reflected by the antenna and received by a receiving antenna.

  8 and 9 show signal propagation and transmission in the communication network shown in FIG. 8 illustrates a case where the cancel circuits 551 and 552 function as the first sneak signal suppression circuit according to the present disclosure, and FIG. 9 illustrates that the cancel circuits 551 and 552 function as the second sneak signal suppression circuit according to the present disclosure. Show the case.

  In FIG. 8, the radio signal 811 transmitted from the radio terminal 511 is received by the receiving antenna 532, and is transmitted through the optical fiber transmission line 571 as an optical fiber radio signal 812 by the optical radio conversion unit 561. The optical fiber radio signal 812 is converted into a radio signal 813 by the optical radio conversion unit 562 and transmitted from the transmission antenna 533 to the radio terminal 512. However, the radio signal 813 is received by the reception antenna 534 and becomes a wraparound radio signal 814. Propagated to the cancel circuit 552. At this time, the wraparound radio signal 814 is removed using the radio signal 813 with the configuration shown in FIG. 6 or FIG. A wireless signal 821 transmitted from the wireless terminal 512 is received by the receiving antenna 534 and is transmitted through the optical fiber transmission line 571 as an optical fiber wireless signal 822 by the optical wireless conversion unit 562. The optical fiber radio signal 822 is converted into a radio signal 823 by the optical radio conversion unit 561 and transmitted from the transmission antenna 531 to the radio terminal 511, but the radio signal 823 is received by the reception antenna 532 and becomes a sneak radio signal 824. Propagated to the cancel circuit 551. At this time, the wraparound radio signal 824 is removed using the radio signal 823 with the configuration shown in FIG. 6 or FIG.

  In FIG. 9, a wireless signal 911 transmitted from the wireless terminal 511 is received by the receiving antenna 532, and is transmitted through the optical fiber transmission line 571 as an optical fiber wireless signal 912 by the optical wireless conversion unit 561. The optical fiber radio signal 912 is converted into a radio signal 913 by the optical radio conversion unit 562 and transmitted from the transmission antenna 533 to the radio terminal 512. However, the radio signal 913 is received by the reception antenna 534 and wraps around by the optical radio conversion unit 562. An optical fiber wireless signal 914 is transmitted through the optical fiber transmission line 571. The sneak optical fiber radio signal 914 is propagated to the cancel circuit 551 as a sneak optical fiber radio signal 915 by the optical radio conversion unit 561, and the sneak optical fiber radio signal 915 is a radio signal by the configuration as shown in FIG. 911 to remove. The wireless signal 921 transmitted from the wireless terminal 512 is received by the receiving antenna 534 and is transmitted through the optical fiber transmission path 571 as an optical fiber wireless signal 922 by the optical wireless conversion unit 562. The optical fiber wireless signal 922 is converted into a wireless signal 923 by the optical wireless conversion unit 561 and transmitted from the transmission antenna 531 to the wireless terminal 511, but the wireless signal 923 is received by the reception antenna 532 and wraps around by the optical wireless conversion unit 561. An optical fiber radio signal 924 is transmitted through the optical fiber transmission line 571. The wraparound optical fiber radio signal 924 is propagated to the cancel circuit 552 as a wraparound radio signal 925 by the optical wireless conversion unit 562, and the wraparound radio signal 925 is transmitted using the radio signal 921 with the configuration shown in FIG. 6 or FIG. Removed.

  Here, the amount of delay and the amount of attenuation in the form of FIG. 8 can be determined according to the design and characteristics of the optical wireless converter. 9 can be determined in accordance with the design and characteristics of the optical fiber transmission line 571 and the optical wireless converter connected by the optical fiber transmission line 571. For example, when the length of the optical fiber transmission line 571 is determined in advance, the wraparound optical fiber radio signal arrives at the cancel circuit after a predetermined time has elapsed since the arrival of the radio signal. Therefore, by setting the delay amount of the delay unit to the time when the sneak optical fiber radio signal arrives, the sneak optical fiber radio signal can be suppressed.

  At this time, it is possible to remove the sneak radio signal and the sneak optical fiber radio signal in both the form of FIG. 8 and the form of FIG. 9, but in the case of the form of FIG. 8, the cancel circuit is compared with the form of FIG. Since the time difference between the passing radio signal and the sneaking radio signal is small, the amount of delay required by the delay device used in the cancel circuit can be suppressed to a small value.

  The communication network shown in FIG. 5 using the cancel circuit having the configuration as shown in FIG. 6 or FIG. 7 makes it possible to remove unnecessary radio signals as shown in FIG. 8 or FIG. As shown, the signal quality can be prevented from deteriorating, and the inconvenience that the radio propagation range becomes smaller and the transmission band becomes smaller can be solved. Furthermore, since it becomes possible to simultaneously transmit and receive wireless signals by the cancel circuit, it is possible to extend wireless communication, which has generally performed half-duplex communication by time division multiplexing, to full-duplex communication. .

(Second embodiment)
FIG. 10 is a diagram illustrating a second example of the communication network according to the present disclosure.
The communication network shown in FIG. 10 includes wireless terminals 1011 and 1012, optical wireless converters 1021 and 1022, and an optical fiber transmission line 1081. The optical wireless converter 1021 includes an antenna unit 1041 configured by a transmission antenna 1031 and a reception antenna 1032, a bidirectional cancellation circuit 1061 configured by cancel circuits 1051 and 1052, and an optical wireless conversion unit 1071. The optical wireless converter 1022 includes an antenna unit 1042 including a transmitting antenna 1033 and a receiving antenna 1034, and an optical wireless converter 1072.

  At this time, the wireless terminal 1011 is wirelessly connected to the antenna unit 1041 of the optical wireless converter 1021, and the optical wireless converter 1021 performs optical wireless conversion from the optical wireless converter 1071 via the optical fiber transmission path 1081 by the optical wireless converter 1072. The antenna unit 1042 of the optical wireless converter 1022 is wirelessly connected to the wireless terminal 1012.

  The bidirectional cancellation circuit 1061 is connected to the antenna unit 1041 and the optical wireless conversion unit 1071 inside the optical wireless converter 1021. The cancel circuits 1051 and 1052 constituting the bidirectional cancel circuit can be configured as shown in FIG. 6 or FIG. 7, for example.

FIG. 11 shows signal propagation and transmission in the communication network shown in FIG.
In FIG. 11, a radio signal 1111 transmitted from the radio terminal 1011 is received by the receiving antenna 1032, and is transmitted through the optical fiber transmission path 1081 as an optical fiber radio signal 1112 by the optical radio conversion unit 1071. The optical fiber radio signal 1112 becomes a radio signal 1113 by the optical radio conversion unit 1072 and is transmitted from the transmission antenna 1033 to the radio terminal 1012, but the radio signal 1113 is received by the reception antenna 1034 and wraps around by the optical radio conversion unit 1072. An optical fiber radio signal 1114 is transmitted through the optical fiber transmission line 1081. The wraparound optical fiber radio signal 1114 is propagated to the cancel circuit 1052 as a wraparound radio signal 1115 by the optical wireless conversion unit 1071, and the wraparound radio signal 1115 is transmitted using the radio signal 1111 with the configuration as shown in FIG. Removed. The wireless signal 1121 transmitted from the wireless terminal 1012 is received by the receiving antenna 1034 and transmitted through the optical fiber transmission line 1081 as an optical fiber wireless signal 1122 by the optical wireless conversion unit 1072. The optical fiber radio signal 1122 is transmitted to the radio terminal 1011 from the transmission antenna 1031 as a radio signal 1123 by the optical radio conversion unit 1071, but the radio signal 1123 is received by the reception antenna 1032 and becomes a sneak radio signal 1124. Propagated to the cancel circuit 1051. At this time, the wraparound radio signal 1124 is removed using the radio signal 1123 with the configuration shown in FIG. 6 or FIG.

  Here, the delay amount and attenuation amount in the cancel circuit 1051 can be determined according to the design and characteristics of the optical wireless converter 1021. The delay amount and attenuation amount in the cancel circuit 1052 can be determined according to the design and characteristics of the optical fiber transmission line 1081 and the optical wireless converter connected by the optical fiber transmission line 1081.

  Such a communication network shown in FIG. 10 makes it possible to consolidate the cancel circuit into one optical wireless converter while removing unnecessary wireless signals equivalent to those in the communication network shown in FIG. This configuration is particularly effective when it is required to simplify the configuration of one optical wireless converter as much as possible, such as when one optical wireless converter is located in a remote place.

(Third embodiment)
FIG. 12 is a diagram illustrating a third example of the communication network according to the present disclosure.
The communication network shown in FIG. 12 includes wireless terminals 1211 and 1212, optical wireless converters 1221 and 1222, optical fiber transmission lines 1261 and 1262, and a sneak signal remover 1291. The optical wireless converter 1221 includes an antenna unit 1241 including a transmission antenna 1231 and a reception antenna 1232, and an optical wireless conversion unit 1251. The optical wireless converter 1222 includes an antenna unit 1242 including a transmission antenna 1233 and a reception antenna 1234, and an optical wireless conversion unit 1252. The wraparound signal remover includes optical wireless conversion units 1271 and 1272 and a bidirectional cancel circuit 1281. The bidirectional cancellation circuit 1281 functions as a bidirectional sneak signal suppression circuit according to the present disclosure and has the same configuration as the bidirectional cancellation circuit 1061 shown in FIG. However, the delay amount and attenuation amount in the bidirectional cancel circuit 1281 can be determined according to the design and characteristics of the optical fiber transmission lines 1261 and 1262 and the optical wireless converters 1221 and 1222.

  At this time, the wireless terminal 1211 is wirelessly connected to the antenna unit 1241 of the optical wireless converter 1221, and the optical wireless converter 1221 is removed from the optical wireless converter 1251 by the optical wireless converter 1271 through the optical fiber transmission path 1261. The sneak signal remover 1291 is connected to the optical wireless converter 1222 from the optical wireless converter 1272 via the optical fiber transmission path 1262 by the optical wireless converter 1252, and the antenna unit 1242 of the optical wireless converter 1222. Is wirelessly connected to the wireless terminal 1212.

  The optical wireless conversion units 1271 and 1272 function as, for example, a first signal conversion unit and a second signal conversion unit. In this case, the optical fiber transmission lines 1261 and 1262 function as a first optical fiber and a second optical fiber.

  The optical wireless conversion unit 1271 converts the optical fiber wireless signal transmitted through the optical fiber transmission path 1261 into a wireless signal. The optical wireless conversion unit 1272 converts the wireless signal converted by the optical wireless conversion unit 1271 into an optical fiber wireless signal and outputs it to the optical fiber transmission line 1262. The wraparound signal remover 1291 branches the wireless signal converted by the optical wireless conversion unit 1271, and uses the branched wireless signal to send the wireless signal to the optical wireless converter 1222 connected to the optical fiber transmission line 1262. A third suppression signal for suppressing the first sneak optical fiber radio signal received by the antenna unit 1242 provided is generated. Then, when the first sneak optical fiber radio signal is converted into a radio signal by the optical radio converter 1272, the sneak signal remover 1291 synthesizes the third suppression signal with the first sneak optical fiber radio signal.

  The optical wireless conversion unit 1272 converts the optical fiber wireless signal transmitted through the optical fiber transmission path 1262 into a wireless signal. The optical wireless conversion unit 1271 converts the wireless signal converted by the optical wireless conversion unit 1272 into an optical fiber wireless signal and outputs the optical fiber transmission signal to the optical fiber transmission line 1261. The wraparound signal remover 1291 branches the wireless signal converted by the optical wireless conversion unit 1272, and uses the branched wireless signal to send the wireless signal to the optical wireless converter 1221 connected to the optical fiber transmission line 1261. A fourth suppression signal for suppressing the second wraparound optical fiber radio signal received by the antenna unit 1241 provided is generated. When the second sneak optical fiber radio signal is converted into a radio signal by the optical radio converter 1271, the sneak signal remover 1291 synthesizes the fourth suppression signal with the second sneak optical fiber radio signal.

  In the same manner as the communication network shown in FIG. 10, the communication network shown in FIG. 12 removes unnecessary radio signals by the sneak signal remover 1291, and the sneak signal remover on the optical fiber transmission line is removed. It is possible to aggregate them. This configuration is particularly effective in the case where it is required to simplify the configuration of both optical wireless converters as much as possible, such as when both optical wireless converters are located at remote locations.

(Fourth embodiment)
FIG. 13 is a diagram illustrating a fourth example of the communication network according to the present disclosure.
The communication network shown in FIG. 13 includes a plurality of wireless terminals 1311, 1312-1, 1312-2 to 1312-n, a plurality of optical wireless converters 1321, 1322-1, 1322-2 to 1322-n, and a branch type. An optical fiber transmission line 1331 is included. The optical wireless converter 1321 has the same configuration as the optical wireless converter 521 in the communication network shown in FIG. The plurality of optical wireless converters 1312-1 and 1312-2 to 1312-n have the same configuration as the optical wireless converter 522 in the communication network shown in FIG. The branched optical fiber transmission line 1331 is branched so that it can be connected to a plurality of optical wireless converters 1312-1, 1312-2 to 1312-n by an optical splitter 1341 installed in the optical transmission line.

  At this time, the plurality of optical wireless converters 1321, 1322-1, 1322-2, 1322-n are configured to remove the sneak radio signal by the cancel circuit immediately after receiving the wraparound radio signal by the receiving antenna as shown in FIG. As a result, the wraparound radio signal can be removed based on the radio signal.

  Such a communication network shown in FIG. 13 makes it possible to establish communication between one-to-many wireless terminals while removing unnecessary wireless signals equivalent to those in the communication network shown in FIG. This configuration is particularly effective when one wireless terminal needs to communicate with a plurality of wireless terminals.

(Fifth embodiment)
FIG. 14 is a diagram illustrating a fifth example of the communication network according to the present disclosure.
The communication network shown in FIG. 14 includes a plurality of wireless terminals 1411, 1412-1, 1412-2 to 1412-n, a plurality of optical wireless converters 1421, 1422-1, 1422-2 to 1422-n, and a branch type. An optical fiber transmission line 1451 is used. The optical wireless converter 1421 has the same configuration as the optical wireless converter 1021 in the communication network shown in FIG. The plurality of optical wireless converters 1412-1 and 1412-2 to 1412-n have the same configuration as the optical wireless converter 1022 in the communication network shown in FIG. The branch type optical fiber transmission line 1451 is branched so that it can be connected to a plurality of optical wireless converters 1412-1, 1412-2 to 1412-n by an optical splitter 1461 installed in the optical transmission line.

  The optical fiber radio signal output from the optical wireless converter 1421 to the branch optical fiber transmission line 1451 is transmitted to all of the optical wireless converters 1422-1, 1422-2, and 1422-n by the optical splitter 1461. In this case, a wraparound optical fiber radio signal is generated in all of the optical wireless converters 1422-1, 1422-2, and 1422-n.

  At this time, out of the cancel circuits 1431 and 1432 constituting the bidirectional cancel circuit 1441 in the optical wireless converter 1421, the cancel circuit 1432 is configured to include a plurality of delay devices and attenuators as shown in FIG. Thus, it is possible to individually remove a plurality of sneak optical fiber radio signals transmitted from the plurality of optical wireless converters 1422-1, 1422-2 to 1422-n.

  With such a communication network shown in FIG. 14, it is possible to establish communication between one-to-many wireless terminals while removing unnecessary wireless signals equivalent to those in the communication network shown in FIG. This configuration is particularly effective when one wireless terminal needs to communicate with a plurality of wireless terminals and when it is required to simplify the configuration of the plurality of optical wireless converters as much as possible.

(Sixth embodiment)
FIG. 15 is a diagram illustrating a sixth example of the communication network according to the present disclosure.
The communication network shown in FIG. 15 has a configuration in which the bidirectional cancel circuit 1441 in the communication network shown in FIG. 14 is arranged in the optical fiber transmission line as a sneak signal remover like the communication network shown in FIG. Specifically, an optical wireless converter 1521 is provided instead of the optical wireless converter 1421 shown in FIG. 14, and an optical fiber transmission line 1451, a sneak signal remover 1591, and an optical fiber are provided between the optical splitter 1461 and the optical wireless converter 1521. A fiber transmission line 1552 is provided in order, and a sneak signal remover 1591 is provided with a bidirectional cancel circuit 1441. The optical wireless converter 1521 has the same configuration as the optical wireless converter 1221 shown in FIG.

  Such a communication network shown in FIG. 15 makes it possible to establish communication between one-to-many wireless terminals while removing unnecessary wireless signals equivalent to those in the communication network shown in FIG. This configuration is particularly effective when one wireless terminal needs to communicate with a plurality of wireless terminals and when it is required to simplify the configuration of all optical wireless converters as much as possible.

(Seventh embodiment)
FIG. 16 is a diagram illustrating a seventh example of the communication network according to the present disclosure.
The communication network shown in FIG. 16 is obtained by extending the one-to-many configuration in the communication network shown in FIG. 13 to a many-to-many configuration. Specifically, wireless terminals 1611-1 and 1611-2 to 1611-m are provided instead of the wireless terminal 1311 shown in FIG. 13, and the optical wireless converter 1621-1 is used instead of the optical wireless converter 1321 shown in FIG. , 1621-2 to 1621-m, and the optical wireless converters 1621-1 and 1621-2 to 1621-m are connected to the branched optical fiber transmission line 1331 by the optical splitter 1642.

  The optical fiber wireless signals output from the optical wireless converters 1621-1, 1621-2 to 1621-m to the branch optical fiber transmission line 1331 are all transmitted to the optical wireless converters 1322-1, 1322-2, 1322-n. A wraparound optical fiber radio signal is generated at. Therefore, the cancel circuit included in the optical wireless converters 1621-1, 1621-2 to 1621-m is configured to include n delay units and attenuators as shown in FIG. This makes it possible to individually remove a plurality of wraparound optical fiber radio signals transmitted from a plurality of optical wireless converters 1322-1, 1322-2, 1322-n as shown in FIG.

  The optical fiber wireless signals output from the optical wireless converters 1322-1 and 1322-2 to 1322-n to the branch optical fiber transmission line 1331 are all transmitted to the optical wireless converters 1621-1 and 1621-2 to 1621-m. A wraparound optical fiber radio signal is generated at. Therefore, the cancel circuit provided in the optical wireless converters 1322-1 and 1322-2 to 1322-n is configured to include m delay units and attenuators as shown in FIG. This makes it possible to individually remove a plurality of wraparound optical fiber radio signals transmitted from a plurality of optical wireless converters 1621-1, 1621-2 to 1621-m as shown in FIG.

  Such a communication network shown in FIG. 16 makes it possible to establish communication between many-to-many wireless terminals while removing unnecessary wireless signals equivalent to those in the communication network shown in FIG. This configuration is particularly effective when a plurality of wireless terminals need to communicate with a plurality of wireless terminals.

(Eighth embodiment)
FIG. 17 is a diagram illustrating an eighth example of the communication network according to the present disclosure.
The communication network shown in FIG. 17 is obtained by extending the one-to-many configuration in the communication network shown in FIG. 14 to a many-to-many configuration. Specifically, wireless terminals 1711-1 and 1711-2 to 1711 -m are provided instead of the wireless terminal 1411 shown in FIG. 14, and the optical wireless converter 1721-1 is used instead of the optical wireless converter 1421 shown in FIG. , 1721-2 to 1721-m, and optical splitters 1762 connect the optical wireless converters 1721-1 and 1721-2 to 1721-m to the branch type optical fiber transmission line 1451.

  With such a communication network shown in FIG. 17, it is possible to establish communication between many-to-many wireless terminals while removing unnecessary wireless signals equivalent to those in the communication network shown in FIG. This configuration is particularly effective when a plurality of wireless terminals need to communicate with a plurality of wireless terminals and when the configuration of the plurality of optical wireless converters is required to be as simple as possible.

(Ninth embodiment)
FIG. 18 is a diagram illustrating a ninth example of the communication network in the present disclosure.
The communication network shown in FIG. 18 is obtained by extending the one-to-many configuration in the communication network shown in FIG. 15 to a many-to-many configuration. Specifically, wireless terminals 1811-1 and 1811-2 to 1811 -m are provided instead of the wireless terminal 1411 shown in FIG. 15, and an optical wireless converter 1821-1 instead of the optical wireless converter 1521 shown in FIG. , 1821-2 to 1821-m, and optical splitters 1862 connect the optical wireless converters 1821-1, 1821-2 to 1821-m to the optical fiber transmission line 1552.

  The optical fiber radio signal output from the optical wireless converter 1271 to the branching optical fiber transmission line 1552 is transmitted to all of the optical wireless converters 1821-1, 182-2 to 1821 -m by the optical splitter 1862. In this case, a wraparound optical fiber radio signal is generated in all of the optical wireless converters 1821-1, 1821-2 through 1821 -m. Therefore, the cancel circuit 1441 is configured to include m delay units and attenuators as shown in FIG.

  The optical fiber radio signal output from the optical wireless converter 1272 to the branch optical fiber transmission line 1551 is transmitted to all of the optical wireless converters 1422-1, 1422-2 to 1422-n by the optical splitter 1461. In this case, a wraparound optical fiber radio signal is generated in all of the optical wireless converters 1422-1, 1422-2 to 1422-n. Therefore, the cancel circuit 1442 is configured to include n delay devices and attenuators as shown in FIG.

  With such a communication network shown in FIG. 18, it is possible to establish communication between many-to-many wireless terminals while removing unnecessary wireless signals equivalent to those in the communication network shown in FIG. This configuration is particularly effective when a plurality of wireless terminals need to communicate with a plurality of wireless terminals and when it is required to simplify the configuration of all the optical wireless converters as much as possible.

  The present disclosure can be applied to the information communication industry.

111, 112, 211, 212, 311, 312, 511, 512, 1011, 1012, 1211, 1212, 1311, 1312-1, 1312-2, 1312-n, 1411, 1412-1, 1412-2, 1412- n, 1611-1, 1611-2, 1611-m, 1711-1, 1711-2, 1711-m, 1811-1, 1811-2, 1811-m: wireless terminals 121, 122: wireless master devices 141, 142 , 241, 242, 243: Transmission function unit 151: Relay network 221, 222, 223: Radio repeater 321, 322, 521, 522, 1021, 1022, 1221, 1222, 1321, 1322-1, 1322-2, 1322 -N, 1421, 1422-1, 1422-2, 1422-n, 1521, 162 -1,1621-2, 1621-m, 1721-1, 1721-2, 1721-m, 1821-1, 1821-2, 1821-m: optical wireless converters 1291, 1591: sneak signal removers 131, 132 31, 232, 233, 234, 235, 236, 341, 342, 541, 542, 1041, 1042, 1241, 1242: antenna part 331, 333, 531, 533, 1031, 1033, 1231, 1233: transmission antenna 332 334, 532, 534, 1032, 10341232, 1234: receiving antennas 351, 352, 561, 562, 1071, 1072, 1251, 1252, 1271, 1272: optical wireless conversion units 551, 552, 1051, 1052, 1431, 1432 : Cancel circuit 1061, 1 81, 1441: Bidirectional cancel circuits 571, 1081, 1261, 1262, 1552: Optical fiber transmission lines 1331, 1451: Branch type optical fiber transmission lines 1341, 1461, 1642, 1762, 1862: Optical splitter 611: Branch device 621: Delay device 631: Attenuator 641: Synthesizer

Claims (8)

An optical wireless converter connected to another optical wireless converter via an optical fiber transmission line,
An antenna unit for transmitting and receiving radio signals to and from a wireless terminal;
A radio signal received by the antenna unit is converted into an optical fiber radio signal and output to the optical fiber transmission line, and an optical fiber radio signal transmitted through the optical fiber transmission line is converted into a radio signal to be transmitted to the antenna unit. An optical wireless conversion unit for output;
The wireless signal output from the optical wireless conversion unit to the antenna unit is branched, and the branched wireless signal is used as the first suppression signal for suppressing the sneak radio signal received by the antenna unit. A first sneak signal suppression circuit that generates and synthesizes the first suppression signal with the sneak radio signal;
An optical wireless converter comprising: An optical wireless converter connected to another optical wireless converter via an optical fiber transmission line,
An antenna unit for transmitting and receiving radio signals to and from a wireless terminal;
A radio signal received by the antenna unit is converted into an optical fiber radio signal and output to the optical fiber transmission line, and an optical fiber radio signal transmitted through the optical fiber transmission line is converted into a radio signal to be transmitted to the antenna unit. An optical wireless conversion unit for output;
A second suppression unit that branches a radio signal output from the antenna unit to the optical wireless conversion unit and suppresses a sneak optical fiber radio signal received by the antenna unit included in the other optical wireless converter; A second sneak signal suppression circuit that generates a signal using the branched radio signal and synthesizes the second suppression signal with the sneak optical fiber radio signal;
An optical wireless converter comprising: An optical wireless converter connected to another optical wireless converter via an optical fiber transmission line,
An antenna unit for transmitting and receiving radio signals to and from a wireless terminal;
A radio signal received by the antenna unit is converted into an optical fiber radio signal and output to the optical fiber transmission line, and an optical fiber radio signal transmitted through the optical fiber transmission line is converted into a radio signal to be transmitted to the antenna unit. An optical wireless conversion unit for output;
The wireless signal output from the optical wireless conversion unit to the antenna unit is branched, and the branched wireless signal is used as the first suppression signal for suppressing the sneak radio signal received by the antenna unit. A first sneak signal suppression circuit that generates and synthesizes the first suppression signal with the sneak radio signal;
A second suppression unit that branches a radio signal output from the antenna unit to the optical wireless conversion unit and suppresses a sneak optical fiber radio signal received by the antenna unit included in the other optical wireless converter; A second sneak signal suppression circuit that generates a signal using the branched radio signal and synthesizes the second suppression signal with the sneak optical fiber radio signal;
An optical wireless converter comprising: A sneak signal remover disposed in the optical fiber transmission line of a communication network in which a plurality of optical wireless converters that convert a radio signal and an optical fiber radio signal to each other are connected by an optical fiber transmission line,
The optical fiber radio signal transmitted by the first optical fiber provided in the optical fiber transmission line is converted into a radio signal, the radio signal converted by the second signal converter is converted into an optical fiber radio signal, and the first A first signal converter that outputs to one optical fiber;
An optical fiber radio signal transmitted through a second optical fiber provided in the optical fiber transmission line is converted into a radio signal, a radio signal converted by the first signal converter is converted into an optical fiber radio signal, and A second signal converter for outputting to the second optical fiber;
A first sneak optical fiber that branches the radio signal converted by the first signal conversion unit, and that the radio signal is received by an antenna unit provided in an optical radio converter connected to the second optical fiber. A third suppression signal for suppressing the radio signal is generated using the branched radio signal, the third suppression signal is synthesized with the first wraparound optical fiber radio signal, and the second signal conversion unit The wireless signal converted in step 4 is branched, and the wireless signal is suppressed by the second wraparound optical fiber wireless signal received by the antenna unit provided in the optical wireless converter connected to the first optical fiber. A bi-directional sneak signal suppression circuit that generates the suppression signal using the branched radio signal and synthesizes the fourth suppression signal with the second sneak optical fiber radio signal;
A wraparound signal removal machine. A communication network in which a plurality of optical wireless converters that convert a wireless signal and an optical fiber wireless signal to each other are connected by an optical fiber transmission line,
The optical wireless converter according to any one of claims 1 to 3 is used for at least one of the plurality of optical wireless converters.
Communication network. A communication network in which a plurality of optical wireless converters that convert a wireless signal and an optical fiber wireless signal to each other are connected by an optical fiber transmission line,
The wraparound signal removal machine according to claim 4 is arranged in the optical fiber transmission line,
Communication network. A wraparound signal removal method executed by a communication network in which a plurality of optical to wireless converters that convert a radio signal and an optical fiber radio signal to each other are connected by an optical fiber transmission line,
The optical wireless converter is
An antenna unit for transmitting and receiving radio signals to and from a wireless terminal;
A radio signal received by the antenna unit is converted into an optical fiber radio signal and output to the optical fiber transmission line, and an optical fiber radio signal transmitted through the optical fiber transmission line is converted into a radio signal to be transmitted to the antenna unit. An optical wireless conversion unit for output;
With
A first sneak signal suppression circuit divides a radio signal output from the optical wireless conversion unit to the antenna unit, and the first suppression signal suppresses the sneak radio signal received by the antenna unit. Is generated using the branched radio signal, and the first sneak signal suppression procedure for combining the first suppression signal with the sneak radio signal, or
A second sneak signal suppression circuit branches a radio signal output from the antenna unit to the optical to radio conversion unit, and the sneak optical fiber received by the antenna unit provided in the other optical to radio converter A second sneak signal suppression procedure for generating a second suppression signal for suppressing the radio signal by using the branched radio signal and combining the second suppression signal with the sneak optical fiber radio signal;
A wraparound signal elimination method comprising: A wraparound signal removal method executed by a communication network in which a plurality of optical to wireless converters that convert a radio signal and an optical fiber radio signal to each other are connected by an optical fiber transmission line,
The communication network is
The optical fiber radio signal transmitted by the first optical fiber provided in the optical fiber transmission line is converted into a radio signal, the radio signal converted by the second signal converter is converted into an optical fiber radio signal, and the first A first signal converter that outputs to one optical fiber;
An optical fiber radio signal transmitted through a second optical fiber provided in the optical fiber transmission line is converted into a radio signal, a radio signal converted by the first signal converter is converted into an optical fiber radio signal, and A second signal converter for outputting to the second optical fiber;
With
A bidirectional sneak signal suppression circuit branches the radio signal converted by the first signal conversion unit, and the radio signal is received by an antenna unit provided in an optical radio converter connected to the second optical fiber. A third suppression signal that suppresses the generated first wraparound optical fiber radio signal is generated using the branched radio signal, and the third suppression signal is combined with the first wraparound optical fiber radio signal. Procedure or
A bidirectional sneak signal suppression circuit branches the radio signal converted by the second signal conversion unit, and the radio signal is received by an antenna unit provided in an optical radio converter connected to the first optical fiber. A fourth suppression signal that suppresses the generated second wraparound optical fiber radio signal is generated using the branched radio signal, and the fourth suppression signal is combined with the second wraparound optical fiber radio signal. Bidirectional sneak signal suppression procedure,
A wraparound signal elimination method comprising:

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