JP2023168908A - wireless communication system - Google Patents

Abstract

To provide a wireless communication system that can reliably monitor slave stations of each broadcast communication system using a single console when a plurality of broadcast communication systems are used together, and improve convenience.SOLUTION: In a wireless communication system, a plurality of broadcast communication systems are controlled with one console 10. When slave station monitoring is performed by sending slave station monitoring instructions to slave stations of the plurality of broadcast communication systems and receiving slave station monitoring responses, if slave station numbers are duplicated in the plurality of broadcast communication systems, the console 10 sequentially performs sending the slave station monitoring instruction and receiving the slave station monitoring response, as a set, targeted for the numbers, for each broadcast communication system.SELECTED DRAWING: Figure 5

Description

The present invention relates to a wireless communication system, and particularly to a wireless communication system that can improve convenience when multiple broadcast communication systems with different communication methods are used together.

[Description of prior art]
As a wireless communication system, it is defined by the standard ARIB STD-T86 (see Non-Patent Document 1), and is a digital broadcast communication system with a communication method of 16QAM (quadrature amplitude modulation) (hereinafter referred to as 16QAM system), and the standard ARIB STD- There is a digital broadcast communication system TYPE 2 (hereinafter referred to as QPSK system) which is defined by the T115 (see Non-Patent Document 2) and uses a communication method QPSK (Quadrature Phase Shift Keying).

[Example of configuration of digital broadcast communication system: Figure 6]
An example of the configuration of a general digital broadcast communication system will be explained using FIG. 6. FIG. 6 is an explanatory diagram showing a configuration example of a general digital broadcast communication system.
As shown in FIG. 6, the digital broadcast communication system basically includes master station equipment, relay station equipment, and slave station equipment.
The master station equipment includes an operation console 11 and a master station 12.
The console 11 is installed, for example, in a municipal office, and performs reporting operations and the like.
The master station 12 sends notifications via radio waves to receiving equipment serving as slave stations.
The relay station equipment includes a relay station 21 that relays wireless communication between the master station 12 and slave station equipment.

Further, as slave station equipment, an outdoor loudspeaker slave station 31, a door-to-door receiver 32, and a retransmission slave station 33 are provided.
The outdoor loudspeaker slave station 31 is mainly installed outdoors, receives radio waves from the master station 12, and outputs loudspeaker audio.
The door-to-door receiver 32 is mainly installed in a building, receives radio waves from the master station 12, and outputs audio.
Retransmission slave station 33 relays communication between relay station 21 and other slave station equipment. In some cases, the retransmission slave station 33 relays communication between the master station 12 and other slave station equipment.
The configuration described above is a basic configuration example of a digital broadcast communication system, and there is no difference between a 16QAM system and a QPSK system.

The QPSK system is a standard that was created to make the 16QAM digital broadcast communication system that has been used so far simpler and cheaper. system is mainly introduced.

[System combination]
Since QPSK systems will become mainstream in the future, it is conceivable that there will be more opportunities to update existing 16QAM systems to QPSK systems. In that case, there will be a period in which the 16QAM system and the QPSK system are used together.
Since the 16QAM system and the QPSK system have different communication methods, each system requires one or more master stations 12 when used together.
However, in order to simplify the operation, it is required that both systems be controlled by one console 11.

[Monitoring of slave station equipment]
The digital broadcast communication system has a slave station monitoring function for monitoring the status of slave station equipment such as the outdoor loudspeaker slave station 31 using the console 11.
In slave station monitoring, a slave station to be monitored is specified from the console 11 and a slave station monitoring instruction is transmitted, and the designated slave station transmits the device status to the master station 12 in a slave station monitoring response. The master station 12 transfers the device status to the console 11, and the console 11 displays the monitoring results.

The slave station equipment is assigned a number (slave station number) for individually specifying a call destination at the time of broadcasting, and monitoring of the slave stations from the console 11 is also performed in units of numbers.
Each broadcast communication system assigns its own slave station number, so if the systems are used together, the same slave station number will be assigned to the slave station of the 16QAM system and the slave station of the QPSK system. Sometimes.

[Conventional slave station monitoring sequence (1): Figure 7]
Here, the conventional slave station monitoring sequence (1) will be explained using FIG. 7. FIG. 7 is an explanatory diagram showing a sequence (1) of slave station monitoring in a conventional wireless communication system.
As shown in FIG. 7, when two systems are used together, the console 11 sequentially designates slave station numbers and transmits slave station monitoring instructions to the master stations of both systems all at once. In the example of FIG. 7, first, a slave station monitoring instruction for the slave station with slave station number 1 is output (S11, S12).

When the master station of the 16QAM system receives the slave station monitoring instruction, it transmits the slave station monitoring instruction to the outdoor loudspeaker slave station with target slave station number 1 (S13).
When the outdoor loudspeaker slave station receives the slave station monitoring instruction, it transmits a slave station monitoring response (S14), and the response is transmitted to the console 11 via the master station of the 16QAM system (S15).

On the other hand, in the example of FIG. 7, the QPSK system is not provided with the slave station with slave station number 1, so the master station of the QPSK system does not transfer the slave station monitoring instruction from the console 11.
Therefore, the console 11 can normally receive the response from the outdoor loudspeaker of the slave station number 1 of the 16QAM system without colliding with the responses from the plurality of slave stations.
In this way, even if a plurality of broadcast communication systems are used together, if the slave station numbers do not overlap, the slave stations can be monitored normally.

[Conventional slave station monitoring sequence (2): Figure 8]
Next, the conventional slave station monitoring sequence (2) will be explained using FIG. 8. FIG. 8 is an explanatory diagram showing a sequence (2) of slave station monitoring in a conventional wireless communication system.
In the conventional wireless communication system, even if the same slave station number (here, slave station number 1 (No. 1) exists in the 16QAM system and the QPSK system), the console 11 performs the same operation as shown in FIG. Perform similar processing.
That is, as shown in FIG. 8, the console 11 simultaneously transmits a slave station monitoring instruction for "slave station number 1" to the master stations of the 16QAM system and the QPSK system (S21, S22).

Then, when each master station receives the slave station monitoring instruction, the master station of the 16QAM system transmits a slave station monitoring instruction to the outdoor amplification slave station with slave station number 1 of the 16QAM system (S23), and the parent station of the QPSK system The station transmits a slave station monitoring instruction to the outdoor loudspeaker slave station with slave station number 1 of the QPSK system (S24).

The outdoor loudspeaker slave station of the 16QAM system and the outdoor loudspeaker slave station of the QPSK system transmit a slave station monitoring response to the console 11 via the master station in response to the slave station monitoring instruction (S25, S26), and the master station The slave station monitoring response is transferred to the console 11 (S27, S28).

At the console 11, the slave station monitoring responses of the two broadcast communication systems are received almost simultaneously by the same slave station number 1, and the collision causes an abnormality in the processing.
That is, in the conventional wireless communication system, when one console 11 is used, if multiple systems have the same slave station number, the slave stations cannot be monitored properly. Therefore, a restriction arises in that only one slave station is monitored and the other is not monitored.

[Related technology]
Note that, as a conventional technology related to a wireless communication system in which a plurality of communication methods are mixed, there is JP 2020-48065A "Wireless Communication System" (Patent Document 1).
Patent Document 1 describes that in a wireless communication system in which a plurality of communication methods coexist, broadcasting in a plurality of methods is performed with one operation using one operation console.

JP 2020-48065 Publication

Standard ARIBSTD-T86: Municipal digital broadcast communication system, Radio Industries Association Standard ARIBSTD-T115: Municipal digital broadcast communication system TYPE2, Radio Industries Association

As mentioned above, in conventional wireless communication devices, when multiple broadcast communication systems with different communication methods are used together, if the multiple broadcast systems have the same slave station number, one control console can There was a problem in that station monitoring was not possible and was inconvenient.

In addition, Patent Document 1 states that when multiple broadcast communication systems are used together, even if those broadcast communication systems have the same slave station number, the multiple broadcast communication systems can be accessed from one operation console. The configuration for monitoring slave stations is not described.

The present invention was made in view of the above-mentioned circumstances, and when multiple broadcast communication systems with different communication methods are used together, the slave stations of each broadcast communication system can be reliably monitored using one operation console. The purpose of the present invention is to provide a wireless communication system that can improve convenience.

The present invention to solve the problems of the conventional example is a wireless communication system in which a plurality of broadcast communication systems are controlled by one operation console, and the operation console is a slave station of the plurality of broadcast communication systems. When sending a slave station monitoring instruction using the monitoring function to a slave station and receiving a slave station monitoring response, if the slave station number is duplicated in multiple broadcast communication systems, the slave station with that number will be targeted. The transmission of a slave station monitoring instruction and the reception of a slave station monitoring response are sequentially performed for each broadcast communication system as a set.

Further, in the wireless communication system of the present invention, when the number of a slave station is duplicated in a plurality of broadcast communication systems, the operator console assigns an identifier for identifying the broadcast communication system to the number. It is characterized by the fact that it is managed by

Further, in the wireless communication system of the present invention, if the operation console does not receive a slave station monitoring response even after a specific time has elapsed after transmitting the slave station monitoring instruction, the operation console transmits the slave station monitoring instruction to the next broadcast communication system. It is characterized by transmitting a slave station monitoring instruction and receiving a slave station monitoring response to the slave station.

According to the present invention, there is provided a wireless communication system in which a plurality of broadcast communication systems are controlled by one operation console, and the operation console monitors slave stations of the plurality of broadcast communication systems using a monitoring function. When sending an instruction and receiving a slave station monitoring response, if the number of the slave station is duplicated in multiple broadcast communication systems, the slave station monitoring instruction for the slave station with that number will be sent and the slave station monitoring response will be sent. Since the wireless communication system is configured to receive station monitoring responses sequentially for each broadcast communication system as a set, even if the slave station numbers are duplicated in multiple broadcast communication systems, the slave station monitoring responses from the slave stations will not be received. This has the effect of preventing collisions, allowing a single operation console to normally receive the slave station monitoring responses of each broadcast communication system, and confirming the operating status, thereby improving convenience.

FIG. 1 is an explanatory diagram showing a configuration example of the present wireless communication system. FIG. 3 is an explanatory diagram of a slave station number management table. 3 is a flowchart illustrating processing when the console 10 monitors a slave station. It is a flowchart of reception processing. FIG. 2 is an explanatory diagram showing a sequence of slave station monitoring in the present wireless communication system. FIG. 1 is an explanatory diagram showing a configuration example of a general digital broadcast communication system. FIG. 2 is an explanatory diagram showing a sequence (1) of slave station monitoring in a conventional wireless communication system. FIG. 2 is an explanatory diagram showing a sequence (2) of slave station monitoring in a conventional wireless communication system.

Embodiments of the present invention will be described with reference to the drawings.
[Overview of embodiment]
A wireless communication system according to an embodiment of the present invention (the present wireless communication system) is a wireless communication system in which a plurality of broadcast communication systems with different communication methods are controlled by one operator console, and the operator console controls a plurality of broadcast communication systems with different communication methods. When performing slave station monitoring by sending a slave station monitoring instruction to a slave station of a broadcast communication system and receiving a slave station monitoring response, if the number of the slave station is duplicated in multiple broadcast communication systems, , the transmission of a slave station monitoring instruction for the relevant number and the reception of a slave station monitoring response are performed sequentially for each broadcast communication system as a set, and if the slave station number is duplicated in multiple broadcast communication systems. It also prevents collisions of slave station monitoring responses from slave stations, and allows you to correctly receive slave station monitoring responses from each broadcast communication system and check the operating status using a single console. It is something that can improve your sexuality.

In particular, in this wireless communication system, when switching from one broadcast communication system to another, even when both broadcast communication systems are used together, the broadcast communication system side It is possible to monitor slave station devices of both systems using one console without making any changes, thereby improving convenience.

[Configuration of this wireless communication system: Figure 1]
An example of the configuration of this wireless communication system will be explained using FIG. 1. FIG. 1 is an explanatory diagram showing an example of the configuration of this wireless communication system.
This wireless communication system uses a digital broadcast communication system based on 16QAM (16QAM system) and a digital broadcast communication system based on QPSK (QPSK system), and is controlled by a single console 10. As shown in FIG. 2, it is equipped with an operation console 10, a master station 13 of the 16QAM system, an outdoor loudspeaker slave station 31a, a door-to-door receiver 32a, a master station 14 of the QPSK system, an outdoor loudspeaker slave station 31b, and a door-to-door receiver 32b. There is.
If necessary, a relay station or a retransmission slave station may be provided.

The master station 13 of the 16QAM system wirelessly transmits a report from the console 10 to the outdoor loudspeaker substation 31a and the door-to-door receiver 32a using the 16QAM method.
Further, when the master station 13 receives a slave station monitoring instruction from the console 10, it transmits the instruction to the target outdoor loudspeaker slave station 31a, and when it receives a slave station monitoring response from the outdoor loudspeaker slave station 31a, , transfers the response to the console 10.

Similar to the outdoor loudspeaker slave station 31 shown in FIG. 5, the outdoor loudspeaker slave station 31a outputs the report received wirelessly from the master station 13 as loudspeaker audio.
Further, when the outdoor loudspeaker slave station 31a receives the slave station monitoring instruction by radio, it responds to the console 10 via the master station 13 with the device status as a slave station monitoring response.
The door-to-door receiver outputs the report received wirelessly from the master station 13 in audio form.
The QPSK system's master station 14, outdoor loudspeaker slave station 31b, and door-to-door receiver 32b operate in the same way as the master station 13, outdoor loudspeaker slave station 31a, and door-to-door receiver 32a, except that the wireless communication method is QPSK. I do.

The operation console 10 is basically a computer equipped with a control section, a storage section, and an interface section, and is connected to an operation section, an audio input section, a display section, a speaker, and the like. Further, the console 10 is connected to the master station 13 and the master station 14 by wire, outputs notifications to both the 16QAM system and the QPSK system, and performs control to monitor each slave station equipment.

Further, the operator console 10 has a slave station monitoring function as in the past, and monitors slave stations for a plurality of broadcast communication systems.
In particular, the operator console 10 of this wireless communication system is characterized by the processing of managing slave station numbers and monitoring slave stations when a plurality of broadcast communication systems are used together.

Specific processing will be described later, but if there is a slave station number that is used in duplicate in multiple broadcast communication systems, the operation console 10 will change the slave station number to the slave station number when monitoring the slave station. Rather than transmitting a monitoring instruction to a plurality of broadcast communication systems all at once, the system first transmits the monitoring instruction to one system, and after receiving the response, transmits the slave station monitoring instruction to another system. As a result, even if there are identical slave station numbers, slave station monitoring responses can be received one by one, and status monitoring can be performed reliably.
These processes are realized by the control unit activating and executing a processing program stored in the storage unit of the console 10.

[Slave station number management table: Figure 2]
The operator console 10 of this wireless communication system is equipped with a slave station number management table for managing the slave station numbers of slave stations connected to the broadcast communication system under its control.
The slave station number management table will be explained using FIG. 2. FIG. 2 is an explanatory diagram of the slave station number management table.
As shown in FIG. 2, the slave station number management table contains, for each item number, the slave station number of the slave station in this wireless communication system and the name of the broadcast communication system to which the slave station belongs (here, 16QAM system or QPSK system) and identifiers, and is stored in the storage section of the console 10.

In particular, the identifier is information added to distinguish between slave station numbers when they are used in multiple broadcast communication systems.
In the example of FIG. 2, slave station number 1 of item number 1 is used in a 16QAM system, and is associated with an identifier of "1-16QAM".
Furthermore, slave station number 1 in item number 4 is used in the QPSK system, and is given the identifier "1-QPSK." The slave station number 1 is a number used in both the 16QAM system and the QPSK system.
In other words, this indicates that the slave station number to which the identifier is attached is duplicated in a plurality of broadcast communication systems.

Further, since slave station number 2 of item number 2 is used in the 16QAM system and is not used in other systems, no identifier is stored. In other words, the slave station numbers to which no identifiers are attached are used only in the broadcast communication system, and there is no possibility that responses from the slave stations will collide when monitoring the slave stations.

As a result, even if the same slave station number is used in a plurality of broadcast communication systems, the console 10 of the present wireless communication system can distinguish each slave station and perform monitoring operations. Further, on the broadcast communication system side, even if the system is used in conjunction with another broadcast communication system, operation can be continued without changing the slave station number.

[Processing during slave station monitoring: Figure 3]
Next, processing in the control section of the console 10 during slave station monitoring will be described using FIG. 3. FIG. 3 is a flowchart illustrating processing when the console 10 monitors a slave station.
As shown in FIG. 3, when executing the slave station monitoring function (regularly or in response to an instruction from the input section), the console 10 reads out the slave station number to be monitored from the slave station number monitoring table. (100), the identifier corresponding to the slave station number is referred to in the slave station number monitoring table, and it is determined whether the slave station number overlaps with another broadcast communication system (102).

If the identifier is stored corresponding to the slave station number, the operation console 10 determines that it is a duplicate of another broadcast communication system (in the case of Yes), and first sends the message to the master station 13 of the 16QAM system. , and sends a slave station monitoring instruction with the relevant slave station number attached (104).
Then, the console 10 waits for a response and performs a reception process (106). The reception process will be described later, but it is a process that limits the time for waiting for a response from the slave station to be monitored to a specific time. If there is no response even after the specified time has elapsed, the process moves to process 108.

After performing the reception process for the 16QAM system, the console 10 then sends a slave station monitoring instruction to the master station 14 of the QPSK system with the slave station number attached (108). This slave station number is the same number as the number attached to the slave station monitoring instruction transmitted in process 104.
Then, the console 10 performs a reception process similar to process 106 (110), and proceeds to process 124.

In this way, in this wireless communication system, for slave station numbers that are duplicated in multiple broadcast communication systems, a slave station monitoring instruction is sent for one system, and after receiving a response, a slave station monitoring instruction is sent to another system. The transmission of the slave station monitoring instruction and the reception of the response are sequentially performed for each broadcast communication system as a set, such as transmitting a slave station monitoring instruction and receiving a response.
As a result, even one operation console 10 can normally receive the status of slave stations of a plurality of broadcast communication systems without conflicting responses.

In the example of FIG. 3, the slave station monitoring instruction is transmitted for the 16QAM system first, but the QPSK system may be transmitted first. In addition, even if there are three or more broadcast communication systems, it is possible to maintain normal operation by sequentially transmitting slave station monitoring instructions and receiving slave station monitoring responses for each broadcast communication system as a set. It is capable of monitoring slave stations.

Further, if it is determined in process 102 that no identifier is stored corresponding to the read slave station number and that it is not duplicated with another broadcast communication system (in the case of No), the operator console 10 , the master station 13 of the 16QAM system and the master station 14 of the QPSK system are simultaneously sent a slave station monitoring instruction with the relevant slave station number attached (120).
Since the slave station number is used only in one broadcast communication system, similarly to the conventional wireless communication system shown in FIG. or the master station 14) transfers the slave station monitoring instruction to the slave station.

In other words, if the number of a slave station in multiple broadcast communication systems does not overlap, the console of this wireless communication system sends a slave station monitoring instruction to the multiple broadcast communication systems for the slave station with that number. It is sent all at once.
In other words, in this wireless communication system, since there is no risk of collision for slave station numbers that are not duplicated in multiple broadcast communication systems, slave station monitoring instructions are sent all at once as in the past. This simplifies the process and allows the slave station monitoring process to be performed quickly.

Then, the console 10 waits for a response from the slave station and performs a reception process (122), and proceeds to process 124 to determine whether all the slave station numbers in the slave station number management table have been read out (at the end of the slave station number). If there are still slave station numbers remaining (in the case of No), the process returns to step 100 and the same process is performed for the next slave station number.

Further, in the process 124, if the process has been completed for all slave station numbers (in the case of Yes), the operation console 10 ends the process.
In this way, the processing when monitoring the slave station on the console 10 is performed.

In FIG. 3, an example is explained in which all slave stations are monitored periodically or by inputting instructions from the console 10. You may also specify and monitor.
In that case as well, the console 10 determines whether or not the numbers of slave stations are duplicated in multiple broadcast communication systems, and if there is a duplicate, the operator console 10 sends a slave station monitoring instruction and monitors the slave stations. The response is received as a set and is performed sequentially for each broadcast communication system.

[Reception processing: Figure 4]
Next, the reception processes shown in processes 106, 110, and 122 in FIG. 3 will be explained using FIG. 4. FIG. 4 is a flowchart of reception processing.
As shown in FIG. 4, when the reception process is started, the console 106 starts a timer implemented by the control unit through program processing (200), and starts counting the response waiting time.
The console 10 then determines whether or not a response has been received from the slave station (202), and if a response has been received (in the case of Yes), it stores the status of the slave station and displays the result ( 206).

In addition, in the process 202, if a response has not been received (in the case of No), the console 10 determines whether the timer has timed up (204), and if the timer has not timed out (in the case of No). ), the process returns to step 202 and waits for a response.
If the timer times up in step 204 (Yes), the console 10 moves to step 206, stores and displays information such as no response, and ends the process.
The reception process is performed in this way.

In particular, by performing the reception process 106 after the process 104 in FIG. 3, the slave station monitoring response from the slave station is limited to a specific time, and if the slave station monitoring response is not received even after the specific time has elapsed, , it is possible to send a slave station monitoring instruction to the next broadcast communication system.

[Sequence of slave station monitoring in this wireless communication system: Figure 5]
Next, the sequence of slave station monitoring in this wireless communication system will be explained using FIG. 5. FIG. 5 is an explanatory diagram showing a sequence of slave station monitoring in this wireless communication system.
As shown in FIG. 5, when a slave station monitoring operation is performed, the console 10 first transmits a slave station monitoring instruction for the slave station with slave station number 1 to the master station 13 of the 16QAM system (S31). , the master station 13 transfers the slave station monitoring instruction to the slave station with slave station number 1 of the 16QAM system (S32).

The outdoor loudspeaker slave station 31a1, which is slave station number 1 in the 16QAM system, receives the slave station monitoring instruction and transmits the status of its own device to the console 10 as a slave station monitoring response (S33). The slave station monitoring response is transferred by the master station 13 to the console 10 and received by the console 10 (S34).

After that, the console 10 transmits a slave station monitoring instruction for the slave station with the slave station number 1 to the QPSK system master station 14 (S35), and the master station 14 transmits the slave station monitoring instruction to the slave station with the slave station number 1. The slave station monitoring instruction is transferred to (S36).
The outdoor loudspeaker slave station 31b1, which is a slave station with slave station number 1 in the QPSK system, receives the slave station monitoring instruction and transmits a slave station monitoring response to the console 10 (S37), and the slave station monitoring response is as follows. It is received by the console 10 via the master station 14 (S38).
In this way, the slave station monitoring sequence in this wireless communication system is performed.

[Effects of embodiment]
According to this wireless communication system, a plurality of broadcast communication systems with different communication methods (for example, a 16QAM system and a QPSK system) are controlled by one console 10, and the console 10 controls multiple When performing slave station monitoring in which a slave station monitoring instruction is sent to a slave station of a broadcast communication system and a slave station monitoring response is received, if the slave station number is duplicated in multiple broadcast communication systems, The sending of a slave station monitoring instruction for the relevant number and the reception of a slave station monitoring response are performed as a set, and are performed sequentially for each broadcast communication system, so it is possible to perform slave station monitoring for each broadcast communication system. , it prevents collisions of slave station monitoring responses from slave stations, and allows you to correctly receive slave station monitoring responses from each broadcast communication system and check the operating status from a single console, making it convenient. It has the effect of improving the

The present invention improves convenience by making it possible to reliably monitor slave stations of each broadcast communication system using a single console when multiple broadcast communication systems with different communication methods are used together. Suitable for wireless communication systems.

10, 11...Operation console, 12...Main station, 13...Main station (16QAM), 14...Main station (QPSK), 21...Relay station, 31...Outdoor loudspeaker slave station, 32...Door-to-house receiver, 33...Retransmission Slave station

Claims (3)

A wireless communication system that controls multiple broadcast communication systems with one console,
When the console transmits a slave station monitoring instruction using the monitoring function to the slave stations of the plurality of broadcast communication systems and receives a slave station monitoring response, the operation console controls the slave stations of the plurality of broadcast communication systems. If the numbers overlap, the transmission of the slave station monitoring instruction targeting the slave station of the number and the reception of the slave station monitoring response are sequentially performed for each of the broadcast communication systems as a set. Communications system. The operation console is characterized in that when the number of a slave station is duplicated in the plurality of broadcast communication systems, the number is managed by adding an identifier for identifying the broadcast communication system to the number. The wireless communication system according to claim 1. If the console does not receive a slave station monitoring response even after a specific time has elapsed after transmitting the slave station monitoring instruction, the operation console transmits the slave station monitoring instruction to the next broadcast communication system and sends the slave station monitoring instruction to the next broadcast communication system. 3. The wireless communication system according to claim 1, further comprising receiving a slave station monitoring response.

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