JP2006211491A - Digital radio system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital radio system which eliminates the need for retransmission when a mobile station move from one area to another and makes a hand-over of communication from a current area to a next movement-destination area through a simple procedure. <P>SOLUTION: In the digital radio system comprising a control station, a plurality of base stations connected to the control station, and a plurality of mobile stations moving nearby the plurality of base stations; each of the plurality of mobile station transmits reply data including its mobile station code when receiving a base station code from an arbitrary base station among the plurality of mobile stations. A base station having received it stores the mobile station code included in the reply data, imparts replay order of a mobile station present in the area of the base station according to the stored information and transmits it, and transmits the mobile station code of the mobile station to the base station according to the reply order from the mobile station having received the reply order, thereby recognizing the mobile station present in the area of the base station. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a digital radio system, and more particularly to control of a mobile station that moves between a plurality of base stations.

  As a conventional digital radio system, for example, a radio communication system (Patent Document 1) for grasping the status of a mobile station by a polling signal between a base station and a mobile station on the base station side, or along a train line There is a radio system for a train (Patent Document 2) in which a mobile radio station installed on a train that has a plurality of base stations and moves on a track performs radio communication with these base stations.

JP 2004-172942 A JP 2001-268628 A

In a conventional digital radio system, for example, when a response signal of a polling signal is divided and transmitted, retransmission is necessary when a mobile station moves between areas while receiving one piece of divided data. There is a problem that.
In particular, in the case of a radio system for trains, it is necessary for a train (mobile station) straddling an area to perform communication handover between the current area and the next moving area in a complicated procedure, and data loss is large.

  The object of the present invention has been made in view of the above, and when a mobile station moves between areas, it does not require retransmission, and handover of communication between the current area and the next moving area An object of the present invention is to provide a digital wireless system capable of performing the above in a simple procedure.

In order to solve the above-described conventional problems, the invention described in claim 1 includes a control station, a plurality of base stations connected to the control station, a plurality of mobile stations moving around the plurality of base stations, When each of the plurality of mobile stations receives a base station code from an arbitrary base station of the plurality of base stations, the mobile station transmits reply data including the mobile station code of the local station. Then, the base station that has received the message stores the mobile station code included in the reply data, and assigns the response rank of the mobile station in the area of the base station according to the stored information to the mobile station. And transmitting the mobile station code of the mobile station to the base station based on the response order from the mobile station that has received this, thereby recognizing the mobile station existing in the area of the base station. It is characterized by performing.

In order to solve the above-described conventional problems, the invention according to claim 2 is the digital radio system according to claim 1, wherein each of the mobile stations acquires a moving direction of the mobile station, and The mobile station code of the mobile station is transmitted to the base station based on the response order, so that the mobile station existing in the area of the base station is recognized together with the moving direction of the mobile station.

In order to solve the above-mentioned conventional problems, the invention according to claim 3 is the digital radio system according to claim 1 or 2, wherein each of the plurality of base stations is connected to another base station. When the mobile station code transmitted from the mobile station includes means for acquiring transmission information a predetermined time before and includes the base station code of another base station, the base station code of the local station The mobile station code is transmitted, and the other base station receiving the code transmits communication data to be transmitted to the mobile station for a predetermined time.

In order to solve the above-mentioned conventional problems, the invention according to claim 4 is the digital radio system according to claims 1 to 3, wherein the plurality of base stations transmit base stations to arbitrary mobile stations. When there are a plurality of stations, the timing information of the mobile station is transmitted to each of the plurality of base stations that transmit to the mobile station, and the base station that receives the information generates the same timing, and based on the generated timing The plurality of base stations transmit data to the mobile station.

  According to the present invention, a digital radio that does not require retransmission when a mobile station moves between areas and can perform a handover of communication between the current area and the next moving area in a simple procedure. A system can be provided.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an example of a system block diagram showing a configuration of a digital radio system according to an embodiment of the present invention.
A plurality of base stations 21 to 23 are installed along a railway such as a Shinkansen or a highway, and communicate with radio mobile stations mounted on mobile stations 31 to 33 such as trains and automobiles moving on the railway track or road. Do.
Specifically, in the case of a train radio system, a coaxial leak cable is routed along the track, or in the case of a radio system on an automobile and road such as a highway, a coaxial leak cable is wired. A base station is installed at every interval, and each base station is managed by a control station.
In the figure, each base station 21 to 23 is connected to the control station 1, and the control station 1 distributes synchronization information, for example, and synchronizes between the stations according to the synchronization information distributed by these base stations. Control is performed.
Then, wireless communication is established between the base station and a mobile station mounted on a train in the area of each base station or a mobile station mounted on an automobile.

FIG. 2 is an example of an operation flow diagram (part 1) showing the operation of the digital radio system according to the embodiment of the present invention.
In FIG. 1 described above, there are a base station 21, a base station 22, and a base station 23 controlled by the control station 1, and a mobile body 31, a mobile body 32, and a mobile body 33 are present in the area of the base station 22. The mobile station 31 also straddles the area of the base station 21, and the mobile station 33 straddles the area of the base station 23.
Then, data communication such as IP communication is performed wirelessly between each base station and a mobile station in the area.

Here, the mobile station 31 that has moved from the area of the base station 21 into the area of the base station 23 receives the base station code from the base station 22, and receives this to identify the mobile station 31 to the base station 22. Send (reply) the code.
The identification code is added to the slot used for the control channel in the radio frame.
The base station 22 stores the returned identification code together with the returned time for a predetermined time.
Then, the base station 22 periodically transmits an identification code with a response order assigned to each mobile station.
The mobile station 31 transmits (replies) an identification code to the base station 22 according to this response order, so that the base station 22 recognizes the mobile station 31 existing in this area.
Similar operations are performed in the mobile station 32 and the mobile station 33 to enable communication with each base station for each mobile station moving in the area of the base station.
In addition, when the base station 22 assigns the response code to each mobile station as described above, for example, based on the time information d62 received by each mobile station in the memory table of FIG. The response order is determined based on the order of reception from the mobile station.

FIG. 5 is an example of an operation flow diagram (part 2) showing the operation of the digital radio system according to the embodiment of the present invention.
When the moving direction of the mobile station mobile station is known in advance, for example, it can be predicted that the mobile station 31 moves from the base station 21 to the base station 22 and then moves to the base station 23.
Therefore, the mobile station 31 can follow the above-mentioned response order and transmit an identification code to which information on the moving direction is added.
For example, the movement direction is obtained by acquiring the movement direction by grasping the movement direction in advance by the control station 1 from the train operation schedule or by grasping the movement direction by GPS (Global Positioning System). In a simple case, it is possible to easily grasp and set the moving direction.

Therefore, a case where the mobile station 33 moves from the area of the base station 22 to the area of the base station 23 will be described.
When the moving direction is determined from the base station 22, the transmission data is transmitted to the base station 23 via the control station 1 or directly, and the base station 23 stores the data transmitted from the base station 22 for a certain period of time.
The mobile station 33 moves into the area of the base station 23 and receives the base station code from the base station 23.
Then, the mobile station 33 adds the codes of the base stations 22 and 23, which are the previous areas, to the identification code and transmits (replies).
When the base station 23 obtains transmission data for a certain time to be sent to the mobile station 33 from the base station 22 in advance, and receives the identification code of the mobile station 33 to which the codes of the base station 22 and the base station 23 are added. The base station 23 transmits the transmission data from the predetermined time before to the mobile station 33.
By such an operation, it is possible to transmit and receive data between the base station and the mobile station with respect to the mobile station moving across the areas.
In general, communication between a base station and another base station has a transmission rate that is 10 times higher than communication between a base station and a mobile station.

FIG. 6 is an example of a memory table diagram of the base station of the digital radio system according to the embodiment of the present invention.
The base station transmits a specific slot of a radio frame, which is a format of radio data, with a unique code of the base station, and the mobile station that has received the code transmits a predetermined frame of the radio frame, which is a format of radio data. A code unique to the mobile station is added to the slot and transmitted (returned).
That is, in a digital radio system composed of a plurality of base stations and a plurality of mobile stations moving around the base station, a code different for each base station is given to a slot of a radio frame which is a transmission format of the base station, A code different for each mobile station is assigned to the slot of the radio frame from the mobile station that has received this, and transmitted (returned).
In the data transmission / reception shown in FIG. 2 (operation flow part 1) or FIG. 5 (operation flow part 2), the identification code of the mobile station is transmitted (returned) to the base station side. On the station side, information on mobile stations existing in the base station area is stored for a certain period of time.
The stored data includes a mobile station-specific code “mobile station code D61” included in the identification code, a response time “response time D62” from the mobile station, and the mobile station before the base station area. "Previous base station code D63" when the base station code of the area is held, "movement direction D64" indicating the direction of movement of the mobile station, and the like.
These data are stored as identification codes for each mobile station acquired by the control channel.

For example, in the first row of the table of FIG. 6, when a mobile station having a unique code of “0001” as the mobile station code D61 transmits a response to the base station, if this is received, "08:20" is stored at the response time D62.
If the previous base station code is added to the response signal, the base station code “k01” is added to the previous base station code D63, and the mobile station is moving When the direction D64 is added, information indicating a moving direction of “1” is stored.
For example, in the third row of the table in FIG. 6, a mobile station having a unique code of the mobile station code D61 “0013” transmits a response to the base station and receives it at a response time D62 “08:32”. The previous base station code D63 “k01” and the moving direction D64 “1” have moved from the same base station as the mobile station of “0001” in the first row and are traveling in the same direction. I understand.
For example, in the second row of the table in FIG. 6, a mobile station having a unique code of the mobile station code D61 “0012” transmits a response to the base station, and receives this response time D62 “08:25”. The previous base station code D63 “k03” and the moving direction D64 “2” have moved from the mobile station of “0001” in the first row or “0013” in the third row from another base station, You can see that it is moving in a different direction.
That is, for example, in the case of a train system, assuming an up train and a down train, if the mobile station codes “0001” and “0013” are up trains, it is understood that “0012” is a down train.

FIG. 4 is an example of a block diagram of a mobile station according to the embodiment of the present invention.
In the figure, an antenna 408 transmits a received signal transmitted from a base station (in the case of FIG. 1 described above, any of the base stations 21 to 23) to a demodulator 404 via a duplexer 402 via a coaxial leakage cable. A signal that is input or output from the modulation unit 403 via the duplexer 402 is transmitted to the base station (one of the base stations 21 to 23 in the case of FIG. 1 described above) via the coaxial leakage cable.
The demodulator 404 demodulates and demodulates the received signal transmitted from the base station (in the case of FIG. 1 described above, one of the base stations 21 to 23) via the coaxial leaky cable, the antenna 408, and the duplexer 404. Information is output to the control unit.
The synchronization detection unit 406 detects the synchronization bit of the frame of the signal demodulated by the demodulation unit 404.
The synchronization change amount detection unit 407 calculates a delay time according to the synchronization bit detected by the synchronization detection unit 406 and establishes synchronization between the base stations.
The modulation unit 403 modulates the information generated by the control unit 401, and transmits the modulated signal from the duplexer 402 and the antenna 408 to the base station side via the coaxial leakage cable.
In addition, the mobile station has a memory unit (not shown) that stores data received from the base station, for example, stores a base station code acquired through a control channel, or stores various data acquired through a communication channel. To do.

Furthermore, in FIG. 4, when making the base station follow the reference timing of the mobile station in establishing communication at high speed, a timing generation unit 405 and a free-running timing generation unit 501 are added.
The timing generation unit 405 adjusts the timing of the mobile station based on the delay time information detected by the synchronization detection unit 406, and generates a reception signal, that is, a timing synchronized with the base station.
The free-running timing generation unit 501 generates a free-running timing regardless of the received signal, and the synchronization change amount detection unit 407 performs the preceding change in the mobile station according to the change amount of the delay time with respect to the free-running timing. The delay time difference between the base station and the base station after movement is detected, and the information is transmitted to the base station after movement, and the transmission timing of the base station (after movement) is adjusted.
In this way, when the mobile station is moved in the base station area, the mobile station's timing tries to follow the received signal from the previous base station, and between the previous base station and the moved base station. Thus, the same delay timing can be obtained for both the base station before movement and the base station after movement.

FIG. 3 is an example showing a block diagram of a base station according to the embodiment of the present invention.
In the figure, the control unit 301 controls the entire base station, generates information to be transmitted, and receives the transmitted information.
The duplexer 302 sends the transmission signal output from the modulation unit 303 to the mobile station via the coaxial leakage cable, and inputs the transmission signal sent from the mobile station via the coaxial leakage cable to the demodulation unit 304.
The demodulator 304 demodulates the signal received from the coaxial leakage cable via the duplexer 302 and outputs the demodulated information to the controller 301.
The error information receiving unit 307 extracts the delay time difference information transmitted from the mobile station from the demodulation information received by the control unit 301 and outputs the information to the timing generation unit 305.
The timing generation unit 305 generates a frame timing whose timing is adjusted according to the delay time difference information input from the error information reception unit 307.
The modulation unit 303 modulates the information generated by the control unit 301 at the timing generated by the timing generation unit 305, and sends the modulated signal to the mobile station side via the duplexer 302 and the coaxial leakage cable. To do.
Further, the base station has a memory unit (not shown) for storing data received from the mobile station, and management data with the control station 1 and control information used for a control channel with the mobile station (corresponding to FIG. 6 described above). ), And stores various data acquired through the communication channel.

According to the embodiment of the present invention, regarding the control of a mobile body in a base station of a digital radio system, a response order is given from the base station to a mobile station in the area, and the base station recognizes the moving direction of the mobile station, It is possible to grasp the data to be sent to the mobile body to which the destination base station has moved and to send the data to the mobile body. Therefore, the loss of data during movement between the base station areas is small. Can be used effectively.
That is, conventionally, in mobile communication in a base station of a digital wireless system, when a mobile station moves between areas while receiving one piece of divided data, retransmission is necessary and data loss is large. For example, the base station gives a response order from the base station to the mobile stations in the area, the base station recognizes the direction of movement of the mobile station, and grasps the data to be sent to the mobile unit to which the destination base station has moved. However, this can be solved by sending data to the mobile unit.

In addition, according to the embodiment of the present invention, one or a plurality of control stations, a plurality of base stations connected to the control station, and a plurality of mobile bodies moving around the base station, the slot of the radio frame from the base station transmission In a digital radio system in which a different code is assigned to each base station and a different code can be transmitted to a slot of a radio frame from the mobile unit, a new frame is added to the slot of the radio frame from the base station. When the base station code is received, the code of the mobile unit is transmitted to the slot of the radio frame, the code from the mobile unit is stored in the base station for a predetermined time, and the radio frame from the base station is stored based on the stored information. A slot is assigned a response order for each mobile unit and periodically transmitted, and a code of the mobile unit is transmitted to a base station according to the response order to a slot of a radio frame from the mobile unit. It can be mobile body present in the predetermined time Chikyoku wireless service area is a digital wireless system can recognize.

In addition, according to the embodiment of the present invention, one or a plurality of control stations, a plurality of base stations connected to the control station, and a plurality of mobile bodies moving around the base station, the slot of the radio frame from the base station transmission In a digital wireless system in which a different code is assigned to each base station and a different code can be transmitted to a slot of a radio frame from the mobile body for each mobile body, the moving direction of the mobile body is acquired to the mobile body When a new base station code is received in a radio frame slot from the base station, the mobile code and the moving direction are transmitted to the radio frame slot of the mobile station. The mobile unit's code and the moving direction are stored for a certain period of time, and by using the stored information, a response order is given to the slot of the radio frame from the base station for each moving direction of the mobile unit, and the periodic transmission is performed. According to the answer order, the mobile unit code and the moving direction are transmitted to the slot of the wireless frame of the mobile unit, and the mobile unit existing in the radio service area of the base station can be recognized including the moving direction of the mobile unit within a certain period of time. It can be a digital radio system.

In addition, according to the embodiment of the present invention, one or a plurality of control stations, a plurality of base stations connected to the control station, and a plurality of mobile bodies moving around the base station, the slot of the radio frame from the base station transmission In a digital radio system in which a different code is assigned to each base station and a different code can be transmitted to each slot in a radio frame from the mobile unit, a fixed time from a neighboring base station between the base stations Providing a means for acquiring previous transmission information, when a new base station code is received in a slot of a radio frame from the base station, the mobile unit code and an old base station code are transmitted to the slot of the radio frame, The base station may be a digital radio system that transmits transmission information of a predetermined time from the old neighboring base station to a slot of a radio frame.

In addition, according to the embodiment of the present invention, one or a plurality of control stations, a plurality of base stations connected to the control station, and a plurality of mobile bodies moving around the base station, the slot of the radio frame from the base station transmission In a digital radio system in which a different code is assigned to each base station and a different code can be transmitted to each slot in a radio frame from the mobile unit, the code from the mobile unit of the base station is fixed. The stored information stored in time may be transmitted to the control station, and the control station may be a digital radio system that transmits only transmission information to be transmitted to the mobile unit within the predetermined time of the base station.

According to the present invention, in wireless communication between a base station and a mobile station in a digital wireless system, the mobile station enters and exits from the base station area by detecting an area (old zone) leaving from the control channel. Is transmitted to the base station and transferred from the base station to the base station (new zone) after moving, and the base station after moving moves a wireless slot such as an IP slot only to the mobile station existing in the base station. Assign and establish wireless communication.
Therefore, it can be set as a system especially suitable for a train radio system or a road traffic radio system.

1 is an example of a system block diagram showing a configuration of a digital radio system according to an embodiment of the present invention. It is an example of the operation | movement flowchart (the 1) which shows operation | movement of the digital radio system which concerns on embodiment of this invention. It is an example which shows the block diagram of the base station which concerns on embodiment of this invention. It is an example of the block diagram of the mobile station which concerns on embodiment of this invention. It is an example of the operation | movement flowchart (the 2) which shows operation | movement of the digital radio system which concerns on embodiment of this invention. It is an example of the memory table figure of the base station of the digital radio system which concerns on embodiment of this invention.

Explanation of symbols

1: control station, 21-23: base station, 31-33: mobile,
301, 401: Control unit, 302, 402: Duplexer, 303, 403: Modulation unit, 304, 404: Demodulation unit, 305, 405: Timing generation unit, 307: Error information reception unit, 406: Synchronization detection unit, 407 : Synchronous change amount detection unit, 501: free-running timing generation unit.

Claims (4)

In a digital radio system comprising a control station, a plurality of base stations connected to the control station, and a plurality of mobile stations moving around the plurality of base stations,
Each of the plurality of mobile stations, when receiving a base station code from an arbitrary base station of the plurality of base stations, transmits reply data including the mobile station code of the own station,
The base station that has received this stores the mobile station code included in the reply data,
With the stored information, the response rank of the mobile station in the area of the base station is given and transmitted to the mobile station,
The mobile station existing in the area of the base station is recognized by transmitting the mobile station code of the mobile station to the base station based on the response order from the mobile station that has received this. Digital wireless system. Each of the mobile stations is present in the area of the base station by acquiring the moving direction of the mobile station and transmitting the mobile station code of the mobile station to the base station based on the response order. 2. The digital radio system according to claim 1, wherein the mobile station is recognized together with the moving direction of the mobile station. When each of the plurality of base stations includes a base station code of another base station included in a mobile station code transmitted from the mobile station with a means for acquiring transmission information from another base station a predetermined time ago, Send the code of the mobile station along with the base station code of your station to other base stations,
3. The digital radio system according to claim 1, wherein the other base station receiving the same transmits communication data to be transmitted to the mobile station for a predetermined time. When there are a plurality of base stations that transmit to an arbitrary mobile station, the plurality of base stations transmit the timing information of the mobile station for each of the plurality of base stations that transmit to the mobile station,
The base station receiving this generates the same timing,
4. The digital radio system according to claim 1, wherein data is transmitted from the plurality of base stations to the mobile station based on the generated timing.

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