JP2003284131A - Digital radio system - Google Patents

Abstract

(57) [Summary] The present invention includes a central unit 4, a base station 18 connected to the central unit 4, and a mobile station 19 connected to the base station 18 via a radio line. It is an object of the present invention to provide a digital radio system in which the number of radio channels is reduced and the time required for line connection is short in a digital radio system for performing voice / data communication with the station 19. A control channel is allocated by assigning a wireless channel for each application (for example, command call, data communication, maintenance call) and switching between control information and call information (voice data, data other than voice data) within the wireless channel. It eliminates the need and shortens the time required for line connection.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a digital wireless system.

[0002]

2. Description of the Related Art At present, most of general digital radio systems are of a multiple access system, which is a system in which each base station allocates a radio channel in response to a request from a calling station. In Japan, TDM is used for mobile phones.
A (Time Division Multiple)
Access Hereinafter, it is referred to as TDMA. ) System, business radio, TDMA system and FDMA (Frequency)
Division Multiple Access
Hereinafter referred to as FDMA. ) Method is used. In this multiple access method, since wireless lines are allocated when there are communication requests from an unspecified number of terminal stations, the required number of wireless lines (the number of wireless channels) is statistically calculated from the usage of wireless lines. It is the sum of the number of communication channels and the number of control channels commonly used by each mobile station.

The above-mentioned multiple access method has a fixed number of radio frequencies or more and is indispensable for communicating between unspecified large number of radio stations. In the system), it is necessary to secure a large number of frequency resources (increase the number of wireless lines), and when securing a large number of frequency resources, there is a drawback that line connection control becomes complicated.

On the other hand, in a wireless system in which it is not necessary to perform complicated line connection control because a large number of frequency resources cannot be secured (the number of wireless lines is large), the SCP
C (Single Channel Per Carr
Hereinafter, it is referred to as SCPC. ) Method is used. However, since the SCPC wireless system does not have the function of controlling the line connection, it has only the same function as the simplex wireless device. Therefore, the SCPC method is unsuitable for constructing a medium-scale or larger wireless system.

A conventional digital wireless system will be described with reference to FIGS. FIG. 2 is a block diagram showing the configuration of a conventional digital wireless system. FIG. 4 is a sequence diagram showing an operation when a command call is made in the conventional digital wireless system. In a conventional digital wireless system, a command call function in which the commander (handler of the central device) and the driver in the mobile station talk with each other, and data that the data terminal of the central device and the data processing device of the mobile station exchange data with each other. There is a communication function and a maintenance call function for calling a telephone terminal of an arbitrary mobile station from a maintenance call telephone of the central unit. In the conventional digital wireless system, three wireless lines are prepared, one channel is pre-allocated to a control channel, and the remaining two channels are allocated as call channels that can be used simultaneously.

First, the configuration of a conventional digital radio system will be described in detail with reference to FIG. Reference numeral 1 is a command operation panel used by the commander to make a call, 2 is a data terminal, and 3 is a telephone for maintenance call. Reference numeral 4 is a central device (also called a control station, line control device, or exchange) that is the core of the present digital wireless system, 5 is a central device control unit for controlling the entire digital wireless system, and 6 is a line exchange. The exchanges, 7, 7 ', are central device interfaces. Reference numerals 8 and 8'represent base stations that are connected to the central unit and are deployed in various places.
Reference numeral 0 is a base station controller, and 11 is a base station radio. Reference numeral 12 is a mobile station that moves within the communication area of the base station 8.
Is a mobile station radio, 14 is a mobile station controller, 15 is a call control panel, 16 is a data processing device, and 17 is a telephone terminal.

Next, the operation of the conventional digital radio system will be described in detail with reference to FIGS. First, the operation when the central unit 4 calls the mobile station 13 by using the command operation panel 1, the data terminal 2, or the telephone 3 will be described. For example, when the communication start request signal is transmitted by operating the command operation panel 1, the central device control unit 5 transmits the communication start request signal to the base station 8 via the central device interface 7. In the base station 8, the communication start request signal input to the base station interface 9 is transmitted to the base station controller 10. When the communication start request signal is transmitted, the base station control unit 10 determines whether or not there is a free communication channel (a communication channel that is not currently used for communication) (block 41). When there is a vacant speech channel, a communication start signal is transmitted from the base station radio 11 to the mobile station 12 on the control channel designated in advance (block 42).
In the mobile station 12, the communication start signal received on the control channel of the mobile station radio 13 is transmitted to the mobile station controller 14. When the communication start signal is transmitted, the mobile station controller 14 determines whether the called terminal (call control panel 15, data processing device 16, or telephone terminal 17) is available (block 43). When the called terminal is available, the mobile station controller 14 sends a notification response signal on the control channel to the base station controller 1 via the mobile station radio 13 and the base station radio 11.
0 (block 44). When the notification response signal is transmitted, the base station controller 10 transmits a channel switching signal to the mobile station controller 14 on the control channel (block 45).
At the same time, a line securing completion notification signal is transmitted to the central unit 4 (block 46). When the channel switching signal is transmitted,
The mobile station controller 14 switches to the communication channel designated by the base station controller 10 (block 47). On the other hand, when the line securing completion notification signal is transmitted, the central device control unit 5 connects the base station 8 and the mobile station 12 via the communication channel designated by the base station control unit 10 (block 48), It is possible to talk with the mobile station 12.

Secondly, the operation when the mobile station 12 calls another mobile station using the call operation panel 15, the data processing device 16, or the telephone terminal 17 will be described. For example, when a communication start request signal is transmitted by operating the call operation panel 15, the mobile station control unit 14 sends the communication start request signal to the base station control unit via the mobile station radio 13 and the base station radio 11. Transmit to 10. When the communication start request signal is transmitted, the base station control unit 10 determines whether or not there is an empty call channel (call channel that is not currently used for communication). When there is a vacant speech channel, the base station radio 11 to the mobile station 1 are controlled by the control channel designated in advance.
2 transmits a communication start signal. When the communication start signal is transmitted, the mobile station controller 14 transmits a notification response signal to the base station controller 10 via the mobile station radio 13 and the base station radio 11. When the notification response signal is transmitted, the base station control unit 10 transmits a channel switching signal to the mobile station control unit 14 on the control channel and also transmits a line connection request signal to the central unit 4. When the line connection request signal is transmitted, the central unit control section 5 determines the state of the mobile station as the partner station (standby state,
Or if it is in a call), and if it is in standby, connect to the line. Then, while transmitting a line connection completion signal to the base station control unit 10, it also transmits a channel switching signal for switching to the call channel designated by the base station control unit 10 to the mobile station that is the partner station. When the channel of the mobile station serving as the partner station is switched, communication between the mobile station 12 and the mobile station serving as the partner station becomes possible.

In the above-mentioned conventional digital wireless system, the number of channels is secured for three functions (command call, data communication, maintenance call), but one of the three channels is controlled. Since it is used as a channel, the number of channels (call channels) that can actually be used for communication is only two for one base station. Therefore, it is not possible to deal with the case where three or more calling stations simultaneously send out communication request signals (call channels cannot be assigned to all calling stations). Therefore, by prioritizing the call channels, it becomes possible to connect the lines with higher priority to the call channels with higher priority,
Make sure that you are less likely to be forcibly disconnected during communication. For example, when making an urgent command call, naturally, a call channel with a high priority is used, but when there is no vacant call channel, the control channel is used to forcibly disconnect the call channel with the lowest priority and an urgent command is issued. Assign to a call. Then, after the emergency command call is completed, the line can be connected again. However, since it is necessary to disconnect extra lines, the immediacy in an emergency may be impaired.

In addition, both of the two use a control channel as a call channel when the call channel is being used and another communication needs to be newly performed, thereby simultaneously using three channels for a call. Although there is a digital wireless system that operates, a control channel is lost, so that a problem may occur due to restrictions on interrupt notification, control communication during handover, and interruption of emergency communication.

Further, if the frequency resources are abundant (if the number of wireless lines is large), the connection by the multiple access method as described above is sufficiently effective, but basically, for one central device. There are n mobile stations (n> 1), and in order to enable quick line connection and communication, the wireless channel assigned to each mobile station is determined according to the frequency of communication (communication). Higher frequency mobile stations are assigned more radio channels). However, there is a drawback in that it is not possible to always secure an emergency wireless channel simply by determining the number of wireless channels of each mobile station according to the high communication frequency. It would be desirable to be able to provide a digital wireless system that eliminates this drawback.

[0012]

In the above-mentioned conventional digital radio system, in order to realize the line connection by the multiple access method, it is necessary to prepare control channels in addition to the necessary number of communication channels and control the lines. There is. Also,
Since the call channels are vacantly assigned, it is necessary to manage the state of the call channel (whether the call channel is vacant or used for communication) at the central unit or the base station. Therefore, when receiving the communication start request signal from the calling station, it is only necessary to confirm whether the called station is in a communicable state (standby state by not communicating with other wireless stations). Instead, it is necessary to confirm whether or not there is a vacant call channel before the line can be connected, so that the time required for the line connection (hereinafter referred to as the line connection time) becomes long. . Due to this defect, there may occur a problem that the transmission of emergency information is delayed.

Therefore, in the present invention, by eliminating the above drawbacks, it is possible to provide communication by using only a necessary number of communication channels and to provide a digital radio system having a short line connection time. To aim.

[0014]

In order to achieve the above-mentioned object, the present invention has a radio channel (for example, a command communication channel, a data communication channel, and maintenance) for each application (for example, command telephone, data communication, maintenance telephone). A call channel) is assigned in advance, and control information and call information (voice, data) are switched at any time within the wireless channel. As a result, the control channel becomes unnecessary and it is not necessary to confirm the presence / absence of a vacant wireless channel, so that the line connection time can be shortened.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A digital radio system which is an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a block diagram showing the configuration of the digital wireless system of this embodiment. FIG. 3 is a sequence diagram showing an operation when a command call is made in the digital wireless system of this embodiment. The digital wireless system of this embodiment has the same function as the conventional digital wireless system shown in FIG. That is, a command call function in which the commander (handler of the central device) and the driver in the mobile station talk with each other, a data communication function in which the data terminal of the central device and the data processing device of the mobile station exchange data with each other, The device has a maintenance call function of calling a telephone terminal of an arbitrary mobile station from the maintenance call telephone of the device. Therefore, the digital wireless communication system of this embodiment has three functions. Three wireless channels are provided according to the number of functions, and each wireless channel is fixed and assigned in advance for command call, data communication, and maintenance call. With this allocation, it may not be possible to simultaneously make a plurality of command calls in the same base station. However, by providing a plurality of command call channels, a plurality of command calls can be simultaneously performed in the same base station. By providing a plurality of data communication channels and a plurality of maintenance call channels, it is possible to simultaneously perform a plurality of data communication and maintenance calls at the same base station. Therefore, multiple calls can be made by setting the number of wireless channels (the number of command call channels, the number of data communication channels, the number of maintenance calls) according to the frequency of use of each function (command call, data communication, maintenance call). Can be performed simultaneously in the same base station.

First, the configuration of the digital radio system of this embodiment will be described with reference to FIG. Reference numeral 1 is a command operation panel used by the commander to make a call, 2 is a data terminal, and 3 is a telephone for maintenance call. Reference numeral 26 is a central device (also called a control station, line control device, or exchange) that is the core of the present digital wireless system, 21 is a central device-side command call control unit for controlling command calls, and 22 is a data communication device. Central device side data communication system control unit, 23
Is the control unit for the maintenance call, which controls the maintenance call.
Reference numeral 6 is a switching unit that carries out circuit switching, and reference numerals 7 and 7 ′ are central device interfaces. Central device side command communication control unit 2
1. The central device-side data communication system control unit 22 and the central device-side maintenance call system control unit 23 respectively provide the number of wireless channels (command call) provided according to the frequency of use of the command call function, the data communication function, and the maintenance call function. The same number as the number of communication channels, the number of data communication channels, and the number of maintenance call channels). For example, there are 5 wireless channels, and among the 5 wireless channels, 1 channel is for command communication, 2 channels are for data communication,
When two channels are used for maintenance calls, the central device side command communication system control unit 21 and the central device side data communication system control unit 2
2. The number of the central device side maintenance communication system control units 23 is 1, 2, and 2, respectively. Reference numerals 18 and 18 'are base stations connected to the central unit and arranged in various places, 9 is a base station interface, and 11 is a base station radio. Reference numeral 19 is a mobile station that moves within the communication area of the base station 18 (or base station 18 '), 13 is a mobile station radio, 20 is a mobile station side command communication system control unit, and 24 is mobile station side data communication. A system control unit, 25 is a mobile station side maintenance call system control unit, 15 is a call operation panel, 16 is a data processing device, and 17 is a telephone terminal.

Next, the operation of the digital wireless system of this embodiment will be described with reference to FIGS. First, the operation when the central unit 26 calls the mobile station 13 using the command operation panel 1, the data terminal 2, or the telephone 3 will be described. For example, by operating the command operation panel 1, a call request signal is transmitted to the command communication control unit 21 on the central unit side. The central device side command communication system control unit 21 confirms whether or not the command communication channel of the base station 18 having the mobile station 19 as the partner station in the communication area is in use (block 31). When the command call channel is not in use, the central device side command call system control unit 21 creates call start request notification data (block 32), and the command call system data line 2
7 is used to transmit the call start request notification data to the base station 18 via the exchange unit 6 and the central unit interface 7 (block 33). The base station 18 transmits the received call start request notification data to the mobile station 19 via the base station radio 11. When transmitting to the mobile station 19, a code indicating that the call start request notification data is control information (hereinafter referred to as a data type code) is added. The mobile station radio 13 transmits the received call start request notification data to the mobile station side command call system control unit 20. When receiving the call start request signal, the mobile station side command call control unit 20 determines that the control information is control information from the data type code added to the call start request notification data, and also determines that the call can be started. (Block 34). On the other hand, when the mobile station side command call system control unit 20 does not receive the call start request signal, it is determined that the call cannot be started because the command call channel is not available. When the call can be started, the mobile station side command call system control unit 20 transmits the call request acceptance data to the central apparatus side command call system control unit 21 via the base station 18 (block 3).
5). When the call request acceptance data is transmitted, a data type code indicating that the call request acceptance data is control information is added as in the case of transmitting the call start request notification data to the mobile station radio 13 described above. When receiving the call request acceptance data, the central device side command call system control unit 21 determines that the data is the control information from the data type code added to the call request acceptance data, and the central device side command call system control unit 21. Transmits voice data on the same command call channel (without changing the radio channel) to the mobile station side command call system control unit 20 via the central device interface 7, the base station 18, and the mobile station radio 13 ( Block 3
6). When transmitting voice data, a data type code indicating that the voice data is call information is added. The mobile station command communication control unit 20 that has received the voice data determines from the data type code that it is call information (block 3).
7). When the voice data is received, the mobile station command communication control unit 20 converts the voice data and outputs the voice. The output voice is a command from the central unit 26. When the mobile station 19 responds to this command to the central unit 26, the mobile station command communication control unit 19 transmits voice data on the same command communication channel (without changing the wireless channel) to the mobile station wireless device. The data is transmitted to the central device side command / call system controller 20 via the base station 18, the central device interface 7, and the exchange 5 (block 38). When transmitting voice data, a data type code indicating that the voice data is call information is added. The central device side command communication system control unit 21 which has received the voice data determines from the data type code that it is the communication information (block 39). Then, the central device side command communication system control unit 21 converts the voice data into voice and outputs the voice. The output voice is a response from the mobile station 19.

As described above, when the central device 26 transmits the voice data by adding the call information after the central device 26 and the mobile station 19 transmit and receive the control information, the mobile station side command communication system control unit 19 Interprets that voice data is received from the call information, converts the voice data into voice, and outputs the voice to each terminal (for example, a speaker).

Similarly, when a call is made from the data terminal 2 or the maintenance call telephone 3, the control information is transmitted / received between the central unit 26 and the mobile station 19, and then the call information is added to the central portion. When the device 26 transmits data (including voice data), the mobile station side data communication system control unit 24 transmits the data to each terminal (for example, FAX), and the mobile station side maintenance call system control unit 25 receives the communication information. It is interpreted that the voice data is received, the voice data is converted into voice, and each terminal (for example, a speaker) is also output.

Secondly, in the case where the mobile station 13 makes a communication request using the call operation panel 15, the data processing device 16, or the telephone terminal 17 (calls the central device 4 or another mobile station). explain. The application you want to use (for example,
A communication request signal is transmitted to the base station 18 (the base station 18 in which the mobile station 19 is present in the communication area) to check the use status of the wireless channel of the (command call), and the presence or absence of a response signal to this communication request signal is checked. . When the usage channel you want to use (for example, the command call channel) is not in use,
Create and send communication start notification data. When transmitting the communication start notification data, a data type code indicating that the communication start request notification data is control information is added. Or later,
Similar to the case where the central device 21 calls the mobile station 19, the corresponding control unit (for example, the central device side command communication system control unit 21) of the partner station (central device or another mobile station) and the corresponding control unit of the mobile station (For example, the command communication system control unit 19 of the mobile station system) is connected by using the data circuit (for example, the command communication system control circuit 27), and then the data type code is changed from the control information to the communication information. Communicate.

As described above, by adding the data type code according to the type of data to be transmitted, it is possible to determine whether the data is control information or call information in each control unit of the central unit and each control unit of the mobile station. Since the determination can be made, the line connection using the control channel in the related art can be performed in the same channel as the communication channel in the present embodiment.

As an additional effect, it is possible to transmit data during voice communication. (The call information can also be transmitted as digital data during voice communication. Generally, if the amount of data is small, it can be transmitted with almost no effect on voice.) The data type code differs depending on the wireless system, but general business In the case of a wireless system, three types of control information, voice data information, and data information other than voice data are sufficient. Therefore, the general business radio system may have a 2-bit data amount as the data type code.

Since the ratio of this data amount is about 1% of the entire data format of the general business radio system, the influence on the data transmission is small. Also, fixed data originally used for other purposes (for example, a synchronization word for synchronizing data) can be used as the data type code.

Further, according to the digital wireless system of the present embodiment, by having the wireless channel and the control unit provided for each application (for example, command call, data communication, maintenance call), the control units are connected to each other. It is possible to eliminate the time required for the handshake, particularly the allocation of the wireless channel before the line connection and the switching to the wireless channel after the line connection. In addition, since each control unit performs data communication in the same wireless channel and performs line control, the control information content of the wired section and the control information content of the wireless section are made the same so that the frame conversion processing at the base station is deleted. Or it can be simplified. Therefore, the line control speed can be improved and the base station can be simplified.

In this embodiment, there are three types of applications (command call,
Although the digital wireless system having data communication and maintenance call) has been described, the present invention is not limited to this. Similarly, in a digital wireless system having two types or four types of applications, by adding a data type code according to the type of data to be transmitted (control information or call information), each control unit of the central device and Each control unit of the mobile station can determine whether the data is control information or call information. Therefore, after the line is connected, it is possible to perform communication on the same wireless channel as when the line is connected.

[0026]

As described above, according to the present invention, since the control channel becomes unnecessary, it is possible to have only the radio channel required for the call, and it is not necessary to confirm the presence or absence of the vacant radio channel. It is possible to provide a digital wireless system with a short circuit connection time.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a digital wireless system that is an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional digital wireless system.

FIG. 3 is a sequence diagram showing an operation when a command call is made in the digital wireless system which is an embodiment of the present invention.

FIG. 4 is a sequence diagram showing an operation when a command call is made in a digital wireless system which is an example of the related art.

[Explanation of symbols]

1: Command operation panel 2: Data terminal 3: Telephone for maintenance call 4: Central unit 5: Central unit side control unit 6: Exchange unit 7, 7 ': Central unit interface 8, 8': Base station 9: Base station interface 10: Base station controller 11, 11 ': Base station radio 12: Mobile station 13: Mobile station radio 14: Mobile station controller 15: Call control panel 16: Data processor 17: Telephone terminal 18, 18': Base station 19: Mobile station 20: Mobile station side command / call system control unit 21: Central device side command / call system control unit 22: Central device side data communication system control unit 23: Central device side maintenance communication system control unit 24: Mobile station Side data communication system control unit 25: mobile station side maintenance communication system control unit 26: central device 27: command communication system line 28: data communication system line 29: maintenance communication system line 31 to 39: blocks 41 to 48: block

Claims (2)

[Claims] 1. A central device having one or more first control means, a plurality of base stations connected to the central device, and one or more second controls connected to the base station via a wireless line. And a mobile station having means, wherein the first control means controls communication with the mobile station, and the second control means controls communication with the central device and communication between the mobile stations. In first and second control means, the number of which is equal to or greater than the number of communication types, and a code which is superimposed on a signal transmitted through the wireless line and identifies the type of the signal. When the lines and the first and second control means are assigned, the time required for the line connection between the central device and the mobile station and the time required for the line connection between the mobile stations are shortened. Characteristic digital wireless system. 2. The digital wireless system according to claim 1, further comprising a plurality of first and second control means and a plurality of said wireless lines used for the same communication type, and performing communication of the same communication type by the central unit. A digital radio system characterized in that the mobile station is configured to perform at the same time.