JPH1084567A - Channel changeover control system between base stations - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a channel changeover control system between base stations in which a channel is switched during communication between a TCH(traffic channel) changeover type and a redialing type, each base station takes more accurately synchronization and a processing load in an exchange controller is relieved. SOLUTION: A part of PHS(personal handy phone system) base station equipments 31 is provided with a GPS(global positioning system) reception means 41 receiving a GPS signal and a synchronization means 51 synchronizing frames on a radio interface by a GPS time signal, an exchange controller 10 is provided with a synchronization state storage means 20 storing information denoting frame synchronization state corresponding to each base station and retrieves the synchronization state storage means 20 upon the receipt of a notice from a moving destination base station of a PHS mobile equipment 2 and executes a protocol by TCH changeover type with a short hit time only for a connecting state and when the base station of a moving destination is in synchronization state and executes a protocol by a redialing type when at least one base station is asynchronous to switch a communication state channel for the PHS mobile equipment 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-base-station channel switching control method of an exchange control apparatus for switching a connection channel from a base station connected by radio to a neighboring base station by moving a communicating mobile station during communication. In particular, the present invention relates to an inter-base-station channel switching control method capable of performing optimal channel switching control regardless of the presence or absence of synchronization between base stations.

[0002]

2. Description of the Related Art Conventionally, in this type of channel switching control method between base stations, for example, as implemented in a PHS (Personal Handy-phone System) which is a mobile communication system in an extremely small radio zone, each system has In the channel switching control method, a single method is fixedly implemented between all base stations.

That is, TDMA on the radio interface
In a system in which frames in the Time Division Multiple Access (Time Division Multiple Access) scheme are synchronized among all base stations, ARIB (Association of Radio Industries)
and Businesses) RCR (Research & Developmen)
t Center for Radio System: Radio wave system development center) STD (Standard) -28, P
TC used when switching channels in HS and short interruption time
H (Traffic Channel: information channel) While switching-type channel switching during communication is performed, in a system where frame synchronization cannot be achieved, re-calling-type channel switching during communication in which a switching destination channel is set by a re-calling procedure is performed.

[0004] In order to perform channel switching during TCH switching type communication with a short channel switching time, it is necessary to synchronize TDMA frames on the radio interface in all PHS base stations. The reason is that, in the TCH switching type communication-time channel switching, a switching destination wireless channel is set in response to a channel switching request, and then the communicating wireless channel is switched from the connected wireless channel to the switching destination wireless channel. That's why.

[0005] One of the methods for synchronizing is that a synchronization signal subjected to synchronization correction according to the length of a signal line for each PHS base station is transmitted from a switching control device to a P-line via a wired signal line.
It has been sent to the HS base station. However, in this method, it is necessary to know the length of the signal line from the switching control device to all the PHS base stations.

[0006]

In the above-described conventional channel switching control method between base stations, when TCH switching type channel switching during communication using a short channel switching time is used, TDMA frames on radio interfaces of all base stations are transmitted. Need to synchronize. For this reason, it is necessary to know the length of the signal line from the switching control device to all the base stations,
Since the accuracy of the signal line length is low, the synchronization accuracy is also low.In the case of loss of synchronization, a failure in channel switching during communication occurs, and the switching control device directly controls synchronization between all base stations. There is a problem that the processing load on the exchange control device is large.

An object of the present invention is to provide a system in which TC
The H-switching type channel switching during communication and the re-calling type channel switching during communication can be carried out, and a more accurate synchronization can be obtained in each base station, and a channel switching control method between base stations which can reduce the processing load on the switching control device. To provide.

[0008]

A channel switching control method between base stations according to the present invention is a switching control for switching a connection from a base station currently connected by radio to a neighboring base station by moving a communicating mobile station during communication. In the channel switching control method between base stations of the device, at least two base stations are connected to a GPS (Glob).
al Positioning System), a GPS receiving means for receiving a time signal, and a synchronizing means for synchronizing a frame on the wireless interface with the time signal, and the switching control device is performing frame synchronization on the wireless interface. The switching control device further includes a synchronization state storage unit that stores the synchronization-in-progress information in association with the base station, and the switching control device, when receiving a synchronization completion notification from the base station, stores a “synchronization state” in the corresponding base station area of the synchronization state storage unit. On the other hand, when a notification of out-of-synchronization is received, the stored “synchronizing” is deleted, and when a notification of a destination base station of the communication mobile device is received from a base station, the synchronization is performed. If both the connected base station and the movement-destination base station are "synchronizing" by searching the state storage means, execute a procedure by channel switching during short-interruption time channel switching type communication, and at least one of If the base station is “asynchronous”, the re-calling procedure sets the communication channel in the destination base station and performs a re-calling type communication channel switching procedure. Channel switching during communication or channel switching during recall-type communication is being executed.

The absolute time obtained from the GPS time signal received by the GPS receiving means has almost no relative error in each base station, so that the base station can synchronize the TDMA frame almost accurately. Also, by notifying and storing that synchronization has been achieved from the base station,
The switching control device can perform optimal channel switching control by distinguishing between switching of a communication channel only between synchronized base stations and switching of a communication channel to an asynchronous base station.

[0010]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a functional block diagram showing an embodiment of the present invention, and FIG. 2 is a functional block diagram showing an embodiment of the detail of FIG.

In the channel switching control method between base stations shown in FIG. 1, PHS base station apparatuses 31 to 33 control radio zones 11 to 13, respectively, and PHS mobile station 2, which is a communication mobile station, controls radio zones. 11 to 13 are sequentially moved. The PHS base station devices 31 to 33 are connected to the exchange control device 10 and
It is assumed that the setting of the communication channel of the mobile device 2 is controlled. The communication partner of the PHS mobile device 2 is omitted in the drawing and is not shown.

The switching control apparatus 10 has a synchronization state storage means 20, and the PHS base station apparatuses 31 and 32 have GPS reception means 41 and 42, synchronization means 51 and 52, respectively.
And the PHS base station apparatus 33 only includes the synchronization state notification means 63, and the GPS receiving means (31) and the synchronization means (3).
2) shall not be deployed.

In the switching control device 10, the synchronization status storage means 20 receives the notification of the synchronization status of each of the PHS base station devices 31 to 33 from the synchronization status notification means 61 to 63, and stores or updates and stores the information. When the switching control device 10 receives a channel switching request accompanying the movement of the PHS mobile device 2 from each of the PHS base station devices 31 to 33, the switching control device 10 refers to the synchronization state storage means 20 and performs a switching procedure, It is assumed that a decision is made as to whether a TCH switching type of a channel switching type with a short interruption time or a re-calling type in which a channel is set by a re-call.

In the PHS base station apparatus 31, a GPS receiving means 41 receives a time signal from a GPS satellite to calculate an absolute time, and a synchronizing means 51 uses a TDMA on a radio interface.
Frame synchronization is assumed. Synchronization status notification means 6
1 receives the notification from the synchronization means 51 and notifies "synchronization completion" or "out of synchronization" to the synchronization state storage means 20 of the exchange control apparatus 10.

GPS receiving means 42, synchronizing means 52, and synchronizing state notifying means 62 in PHS base station apparatus 32
The GPS receiving means 41, the synchronizing means 51, and the synchronizing state notifying means 61 in the PHS base station device 31 are respectively provided.
It has the same function as each.

The PHS base station apparatus 33 does not have the GPS receiving means (43) and the synchronizing means (53), and the synchronizing state notifying means 63 does not have the GPS receiving means (43) and the synchronizing means (53). To the synchronization state storage means 20.

Next, the switching control device 10 and the PHS base station devices 31 to 33 will be described with reference to FIG. In the illustrated exchange control device 10, the exchange control means 30, PH
Each of the S base station devices 31 to 33 has a wireless device 71 to 73
And control means 81 to 83 are additionally provided in FIG.

Synchronization state storage means 20 of exchange control device 10
Receive the notification of the synchronization status from each of the synchronization status notification means 61 to 63 of each of the PHS base station devices 31 to 33 and store or update and store them.

The exchange control means 30 of the exchange control device 10
The synchronization state storage means 20 and each of the PHS base station apparatuses 31 to 31
33 connected to each of the control means 81 to 83,
It shall control the exchange operation of the system. The main functions relating to the present invention will be described later with reference to FIGS.

GPS receiving means 4 of PHS base station apparatus 31
Reference numeral 1 denotes an absolute time calculated from a GPS signal received from a GPS satellite and notified to the control means 81.
Under the control of the control means 81, synchronizes the TDMA frame and monitors the synchronization in cooperation with the GPS receiving means 41 and the wireless device 71, and notifies the control means 81 of the completion or loss of synchronization.

The synchronization status notifying means 61 is to be notified by the control means 81 of "synchronization completed" or "out of synchronization" to the synchronization status storage means 20 of the exchange control apparatus 10. The wireless device 71 includes the PHS mobile device 2 (FIG. 1) and the control unit 8
Under the control of No. 1, it sets a wireless channel and has an interface function.

The control means 81 controls the operation function of the PHS base station apparatus 31, and the monitoring function according to the present invention will be described later with reference to FIG.

Each of the GPS receiving means 42, the synchronizing means 52, the synchronizing state notifying means 62, the radio 72, and the control means 82 in the PHS base station apparatus 32 is the same as each of the components having the same name in the PHS base station apparatus 31. It has a function.

The difference between the PHS base station device 33 and the PHS base station devices 31 and 32 is that, as described above,
Without the PS receiving means (43) and the synchronizing means (53), the synchronizing state notifying means 63 receives the control of the control means 83 and outputs the message "GPS receiving means (43) and synchronizing means (53)".
Is not notified to the synchronous state storage means 20 by the "asynchronous station" information, and the control means 83 does not perform synchronous control.

Next, with reference to FIG. 3 and FIG. 1 and FIG. 2, a description will be given of the switching of the channel during communication of the PHS mobile device 2 with a focus on the procedure in the exchange control means 30 of the exchange control device 10.

Each of the PHS base station apparatuses 31 and 32 having GPS receiving means 41 and 42 respectively has a GPS
Is synchronized with the TDMA frame on the radio interface. Therefore, "Synchronizing" is stored in the corresponding area of the synchronization state storage means 20 of the switching control apparatus 10, and the PHS having no GPS receiving means is stored. It is assumed that “asynchronous” is stored in the corresponding area of the base station device 33.

The PHS mobile device 2 is connected to the radio zone 11
And communicates with the PHS mobile station (not shown) connected to the PHS base station apparatus 31 on the wireless interface via the switching control apparatus 10 and on the wireless interface of the PHS base station apparatus 33. It is assumed that

Here, when the PHS mobile station 2 during a call moves from the radio zone 11 to the radio zone 12, the PHS mobile station 2 requests the PHS base station apparatus 31 during communication to switch the channel and moves. Channel switching to the PHS base station device 32 connected in the wireless zone 12 is performed.

The control means 81 of the PHS base station apparatus 31 which has received the request for channel switching via the radio 71 transmits the request for channel switching to the exchange control means 30 of the exchange control apparatus 10.
Send to

The exchange control means 30 is provided for the PHS base station 3
1 when a channel switching request is received from step 1 (procedure S
1), based on the channel switching request, the synchronization state storage unit 20
Next, the synchronization state of the PHS base station apparatus 31 that is communicating with the PHS mobile device 2 and that requests switching is confirmed (step S
2) The PHS base station apparatus 31 is synchronizing (YE in step S3)
S), and confirms the synchronization state of the PHS base station device 32 to which the PHS mobile device 2 has moved (step S4),
It can be seen that the base station device 32 is in synchronization (YES in step S5).

Accordingly, the switching control means 30 instructs the PHS base station apparatus 31 to perform channel switching by TCH switching-type communication-in-communication channel switching having a short instantaneous interruption time (step S6),
The connection of the communication channel of the S mobile station 2 is established by the PHS base station apparatus 3.
The connection is switched by changing the setting with the PHS base station device 31 by changing the setting between the two (step S7), and the switching procedure ends.

The PHS base station apparatus 31 that has received the instruction of the TCH switching type channel switching during communication transmits the channel switching information during communication corresponding to this instruction to the requesting PHS mobile device 2 as a response to the channel switching request. . The PHS mobile device 2 executes the TCH switching type communication-in-communication channel switching for the PHS base station device 32 of the movement destination in accordance with the content of the responded information, and as shown in FIG.
The PHS mobile device 2-2 communicates within the PHS mobile device.

When the PHS mobile station 2-2 further moves from the radio zone 12 to the radio zone 13, the PHS mobile station 2-2 requests the PHS base station 32 during communication to switch channels. Then, channel switching to the PHS base station device 33 connected in the destination wireless zone 13 is performed.

The control means 82 of the PHS base station apparatus 32 which has received the channel switching request via the radio 72 transmits the channel switching request to the switching control means 30 of the switching control apparatus 10.
Send to

The switching control means 30 executes the procedure shown in FIG. 3, and upon receiving a channel switching request received from the PHS base station device 32 (procedure S1), based on the channel switching request, the synchronization state storage section 20. Next, the PHS mobile station 2-2 confirms the synchronization state of the PHS base station apparatus 32 that is communicating and is the switching request source (procedure S2).
Is in synchronization (YES in step S3), and further checks the synchronization state of the PHS base station device 33 to which the PHS mobile device 2-2 moves (step S4), and the PHS base station device 33 It can be seen that the TDMA frame is out of synchronization with the GPS time signal (NO in step S5).

Accordingly, the switching control means 30 determines that it is impossible to execute the channel switching during the TCH switching type communication having a short instantaneous interruption time, and the requesting PHS mobile device 2-2 determines that the PHS mobile device 2-2 has not performed the channel switching during the re-calling type communication. The PHS base station apparatus 3 performs switching.
2 (step S8), and the switching procedure ends.

The PHS base station apparatus 32, which has received the instruction for the re-calling type communication-time channel switching, transmits the communication-time channel switching information corresponding to this instruction to the requesting PHS mobile device 2-2 as a response to the channel switching request. Send out. The PHS mobile device 2-2 executes a recalling-type communication-in-communication channel switching for setting a communication channel to the PHS base station device 33 of the movement destination according to the recalling procedure in accordance with the content of the responded information, and is illustrated. To communicate within the wireless zone 13
HS mobile device 2-3.

Next, the synchronization in the PHS base station apparatus 31 having the GPS receiving means 41 will be described with reference to FIGS.

The GPS receiving means 41 in the PHS base station apparatus 31, as shown in FIG.
The reception state of the PS signal is monitored (step S11), a change in the reception state is detected, and the reception state is notified to the control unit 81.
When receiving the notification that the GPS signal has been successfully received (YES in step S12), the control unit 81 sends the GPS signal to the synchronization unit 51.
It instructs to synchronize the time signal and the TDMA frame on the wireless interface.

Upon receiving this instruction, the synchronization means 51 sets the GPS
Acting on the receiving means 41 and the wireless device 71, the GPS time signal and the TDMA frame on the wireless interface are synchronized (step S13), and the control means 81 is notified of the synchronization. The control unit 81 having received this notification sends the synchronization via the synchronization state notification unit 61 to the synchronization state storage unit 20 of the switching control apparatus 10 as a “synchronization completion” notification (step S14), and performs the synchronization notification procedure. finish.

On the other hand, if the step S12 is "NO" and the GPS
When receiving from the GPS receiver 41 a notification that the GPS signal cannot be received because the signal cannot be received, the controller 81
Sends a message indicating that synchronization has been lost to the synchronization status storage means 20 of the switching control apparatus 10 via the synchronization status notification means 61 as a "loss of synchronization" notification (step S15). End the out-of-sync notification procedure.

As for the PHS base station apparatus 32 having the GPS receiving means, the PHS base station apparatus 31 described above is used.
It has the same operation function as.

Further, in the PHS base station apparatus 33 having no GPS receiving means, frame synchronization based on the GPS signal cannot be achieved, so the control means 83 informs the synchronization state notifying means 63 that synchronization cannot be achieved. It is sent to the synchronization status storage means 20 of the switching control device 10 as a "asynchronous station" notification.

As shown in FIG. 5 (A), the synchronization state storage means 20 of the switching control apparatus 10 transmits the “synchronization completed” from the PHS base station apparatuses 31 and 32 in the above-described procedure S14.
When the notification is received (procedure S21), the received “synchronization completion” notification is stored as “synchronizing” in the storage area corresponding to each of the PHS base station apparatuses 31 and 32, and the “asynchronous” stored until then is stored. Update (step S22) and end the procedure.

Further, as shown in FIG. 5 (B), the synchronization state storage means 20 of the switching control apparatus 10 stores the "out of synchronization" from the PHS base station apparatuses 31 and 32 in step S15.
When the notification is received or the “asynchronous station” information is received from the PHS base station device 33 (step S23), the received “out of synchronization” notification or the “asynchronous station” information is stored in the storage area corresponding to the PHS base station device 31. The information is stored as “asynchronous”, the “synchronizing” stored up to that time is updated (procedure S24), and the procedure ends.

As described above, the synchronization status storage means 20 of the switching control device 10 stores the synchronization status of all PHS base station devices including the PHS base station devices 31 to 33,
The exchange control means 30 can confirm the synchronization state of all the corresponding PHS base station devices by referring to the synchronization state storage means 20.

In the above description, the synchronization state storage means of the switching control apparatus stores the synchronized / asynchronous state corresponding to all PHS base stations to facilitate the search of the exchange control means. The means may store only the PHS base station that is “synchronizing”, and the switching control device may determine the PHS base station that is not stored as “asynchronous”.

Also, in the above description, in the PHS base station having the GPS receiving means, when the reception state of the GPS signal has changed, the synchronization state is reported from the PHS base station to the switching control apparatus. In order to prevent leakage, the exchange control device may be configured to make an inquiry to the PHS base station at a predetermined time.

The switching controller sets all the base station corresponding areas of the synchronization state storage means to "asynchronous" at the time of starting operation, and receives a notification of the synchronization state from each base station at a predetermined time to synchronize. A configuration for updating the storage content of the state storage means may be adopted.

In the above description, the ARIB RCR STD
Although the TDMA method and the TCH switching type / recalling type in-communication channel switching method in the PHS have been illustrated and described in accordance with the provisions of -28, other mobile communication systems,
The other channel switching method during communication can be applied as long as it has a similar function such as switching between information channels and switching by re-calling.

As described above, the functions can be diversified and realized, and the functional blocks and the operation procedure are illustrated and described. However, the block configuration by separating and merging the functions, the rearrangement of the procedure, and the parallel operation are described above. It is free as long as the function is satisfied, and the above description does not limit the present invention.

[0053]

As described above, according to the present invention, since the base station is provided with the GPS receiving means and the synchronizing means, the absolute time obtained from the GPS time signal received by the GPS receiving means can be used in each base station. Since there are almost no relative errors, the base station can synchronize the TDMA frame almost accurately and easily. Also, by storing the synchronized base station in the synchronization state storage means of the switching control device, it is possible to distinguish between switching of the communication channel only between the synchronized base stations and switching of the communication channel for the asynchronous base station. Optimum channel switching control can be processed. Therefore, the processing load on the exchange control device can be reduced.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing an embodiment of the present invention.

FIG. 2 is a functional block diagram showing an embodiment of the detail of FIG. 1;

FIG. 3 is a flowchart showing one embodiment of a channel switching procedure of the present invention.

FIG. 4 is a flowchart showing one embodiment of a synchronization status notification procedure according to the present invention.

FIG. 5 is a flowchart showing an embodiment of a synchronization state storage procedure according to the present invention.

[Explanation of symbols]

 2, 2-2, 2-3 PHS mobile station 10 exchange control device 11, 12, 13 wireless zone 20 synchronization state storage means 30 exchange control means 31, 32, 33 PHS base station apparatus 41, 42 GPS receiving means 51, 52 Synchronization means 61, 62, 63 Synchronization state notification means 71, 72, 73 Radios 81, 82, 83 Control means

Claims (4)

[Claims] In an inter-base-station channel switching control method of an exchange control apparatus, a communication mobile unit that is communicating moves and switches connection from a base station that is wirelessly connected to an adjacent base station, at least two base stations are connected. The station is GPS (Global Pos
and a synchronization unit for synchronizing a frame on a wireless interface with the time signal, and wherein the switching control unit is synchronized with a frame being synchronized on the wireless interface. The switching control device includes a synchronization status storage unit that stores medium information corresponding to the base station, and the switching control device, when receiving a synchronization completion notification from the base station, stores “synchronization in progress” in a corresponding base station area of the synchronization status storage unit. On the other hand, when a notification of out-of-synchronization is received, the "synchronizing" in the memory is deleted, and when a notification of a destination base station of the communication mobile station is received from a base station, the synchronization state is deleted. When both the connected base station and the destination base station are "synchronizing" by retrieving the storage means, a procedure by channel switching during short-interruption time channel switching type communication is executed, and at least one of them is executed. When the base station is “asynchronous”, a re-calling procedure for setting a communication channel in the destination base station is performed by a re-calling procedure. A channel switching control method between base stations, wherein channel switching during communication or channel switching during recall-type communication is performed. 2. The method according to claim 1, wherein the synchronization status notifying means of the base station having the GPS receiving means sets the synchronization status as G
A base station for notifying the switching control device of a "synchronization completion" when the synchronization means has completed the synchronization and a "loss of synchronization" when the synchronization means has lost the synchronization, when the PS signal reception state has changed. Inter-station channel switching control method. 3. The base station according to claim 1, wherein all of the base stations include a synchronization status notifying unit that notifies the switching control device of a synchronization status of the base station at a predetermined time, and the switching control device transmits the synchronization status to all the base stations. A channel switching control method between base stations, comprising a synchronization state storage means having a corresponding storage area. 4. The synchronous state according to claim 3, wherein the base station having no GPS receiving means notifies the switching control device at a predetermined time of information indicating that the base station does not have the GPS receiving means and the synchronizing means. A channel switching control method between base stations, comprising a notifying unit.