JPH0287728A - Channel switching system during communication - Google Patents

Abstract

PURPOSE:To shorten switching time by allowing a mobile control station or the like to monitor the synchronizing state of each radio channel before and after the changeover and switching a radio channel on the condition of out-of-synchronism of a channel to be switched and the establishment of synchronization of the channel after the changeover CONSTITUTION:A mobile station 2 receiving a channel switching command signal changes the communication frequency from f1 to f2 based on the frequency information included in the signal. As a result out of synchronism takes place in the radio channel 1 of a mobile control station 1a. A synchronizing monitor 41 in the mobile control station 1a monitoring the synchronizing state of the channel 1 detects out of synchronism of the channel 1 and informs the information to a mobile controller 5. Then after frequency changeover, the mobile station 2 applies establishment of synchronization to the radio channel 2 being a channel of destination changeover. After the establishment of synchronization, the synchronizing monitor 2 detects the establishment of synchronization and transfers the information to the controller 5. Then the controller 5 based on the information switches the connection between the digital transmission line and the channel 1 into the connection between the digital transmission line and the channel 2 means of a switch 3.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a channel switching system during communication in a digital mobile communication system.

(Conventional technology) The conventional method will be described below with reference to the drawings.

FIG. 8 is a diagram showing the configuration of a conventional digital mobile communication system, where 1 is a mobile control station and 2 is a mobile station.

Each wireless channel after switching 111 is set to wireless channel 1.
．． 2, and the frequencies of radio channels 1.2 are assumed to be f, , f2, respectively.

In FIG. 8, when mobile device 2 receives a channel switching instruction signal containing frequency information of wireless channel 2, which is a switching destination channel, from mobile control station 1, it switches the communication frequency from fl to f2. Thereafter, synchronization of the wireless channel 2 is established, and after the synchronization is established, a channel switching completion signal indicating that channel switching is completed is sent back to the mobile control station 1 via the channel. When the mobile control station 1 receives the signal, it changes the connection between the digital transmission path and wireless channel 1 to the connection between the digital transmission path and wireless channel 2, and thereafter resumes communication via wireless channel 2. do.

(Problem to be Solved by the Invention) As explained above, in the conventional system, the connection between the wireless channel and the digital transmission path is switched based on the channel switching completion signal returned from the mobile device. Channel switching time increases by the delay and signal processing time. In addition, if the channel switching completion signal is lost or incorrect, there is a problem that the mobile switching center cannot switch the switch, and even if we try to avoid this by retransmitting the signal, the channel switching time will increase. there were.

It is an object of the present invention to provide a channel switching method that solves the problems of the conventional method and achieves shortening of channel switching time.

(Means for Solving the Problems) The features of the present invention for achieving the stated purpose include mobile devices scattered within a plurality of wireless zones, and at least one mobile control unit that transmits and receives digital signals to and from the mobile devices. In the communication channel switching method, the mobile control station or mobile switching center switches the radio channel used for communication during communication between the mobile device and the mobile control station or mobile switching center. Equipped with a synchronization monitoring device, the synchronization status of each radio channel before and after switching is monitored, and the mobile control station or mobile switching center monitors the synchronization status of each radio channel before and after switching, and when the channel to be switched is out of synchronization and the channel is synchronized after switching, the mobile control station or mobile switching center There is a channel switching method during communication that performs switching.

(Operation) According to the present invention, wireless channels are switched using the loss of synchronization of the channel to be switched and the establishment of synchronization of the channel after switching. Since the conventional channel switching completion signal is not required, the channel switching time can be shortened, and the object of the present invention is achieved.

(Embodiment 1) First, a first embodiment of the channel switching system according to the present invention will be described using FIGS. 1 to 3.

FIG. 1 is a diagram showing an example of the configuration of a digital mobile communication system to which the present invention is applied, where Ia is a mobile control station and 2 is a mobile station.

FIG. 2 is a diagram showing an example of the configuration of the mobile control station la,
3 is a switch that connects the digital transmission path and the wireless channel; 41 and 4° are synchronization monitoring devices that monitor the synchronization status of the wireless channels 1 and 2, respectively; and 5 is a mobile control station controller that controls each part of the mobile control station 1a. It is a device.

FIG. 3 is a diagram showing an example of a channel switching sequence when the present invention is applied in a digital mobile communication system using the system configuration shown in FIG. indicates a layer 1 signal (synchronization information).

In Figure 1, the wireless channels used for communication before and after channel switching are wireless channel 1 and wireless channel 2, respectively.
Assume that Furthermore, it is assumed that the frequencies of radio channels 1.2 are f, , f2, respectively.

The operation of the first embodiment will be described below with reference to FIG.

When switching the wireless channel used for communication between the mobile station 2 and the mobile control station 1a from the wireless channel 1 to the wireless channel 2, the mobile control station controller 5 first sends the following information to the mobile station 2: A channel switching instruction signal containing frequency information (frequency rz) of wireless channel 2, which is the wireless channel to be switched to, is sent to the wireless channel! Sending out via 5 simultaneously synchronous monitoring device 4. to start synchronous monitoring of wireless channel 2.

The mobile station 2 that received the channel switching instruction signal changes the communication frequency from fl to f based on the frequency information included in the signal.
Change to 2. As a result, radio channel 1 of the mobile control station
In this case, out of synchronization occurs.

In the mobile control station 1a, the synchronization monitoring device 41, which monitors the synchronization state of the radio channel 1, detects the loss of synchronization of the radio channel 1, and notifies the mobile control station controller 5 of this information.

After switching the frequency, the mobile station 2 establishes synchronization with the wireless channel 2, which is the channel to which the frequency is switched. At this time, in order to establish synchronization, control such as, for example, sending a synchronization pattern from the mobile control station 1a to the radio channel 2 is required. When the synchronization of the radio channel 2 is established, the synchronization monitoring device 4□ detects the establishment of synchronization and transfers this information to the mobile control station control device 5. Based on the information, the mobile control station controller 5
The switch 3 is instructed to switch the connection between the digital transmission path and the wireless channel 1 to the connection between the digital transmission path and the wireless channel 2, and the switching is performed. On the other hand, after establishing synchronization of the radio channel 2, the mobile station 2 sends a channel switching completion signal to the mobile control station 1a via the radio channel 2, and when the mobile control station 1a receives the signal, the channel switching is completed.

(Embodiment 2) Next, a second embodiment of the channel switching system of the present invention will be described using FIGS. 4 to 7.

FIG. 4 is a system configuration diagram of digital mobile communication (A method) when the channel switching method of the second embodiment is used, 6 is a mobile switching center, 71.7□ is a radio base station (hereinafter referred to as
(simply referred to as a base station). The base station C, 7° and the mobile switching center 6 are respectively connected to the digital transmission path 1.2 and the base station ~
They are connected by a signal line 1.2 for transferring control signals between mobile switching centers. Furthermore, the mobile station 2 is connected to the base station 7. ．． 72
and Sowa are connected by radio channel 1.2.

FIG. 5 is a diagram showing an example of the configuration of the base station 71.7□, where 8 is a transmitting/receiving device, 9 is a synchronization monitoring device, IO is a synchronization information insertion device, and 11 is a base station controller that controls each part of the base station. It is a device.

FIG. 6 is a diagram showing an example of the configuration of the mobile switching center 6.
2. ．． 122 is a synchronization information monitoring device; 1; 3 is a mobile switching center control device that controls each part of the mobile switching center 6;

FIG. 7 is a diagram showing an example of a channel switching sequence when the present invention is applied in a digital mobile communication system having the system configuration shown in FIG. 4, in which → indicates a control signal, -→ indicates a layer 1 signal (synchronization information).

The operation of the second embodiment will be described below with reference to the sequence diagram shown in FIG.

When switching the radio channel used for communication between the mobile station 2 and the mobile switching center 6 from the radio channel 1 to the radio channel 2, the mobile switching center control device 6 first tells the mobile station 2, A channel switching instruction signal (2) containing frequency information (frequency r2) of radio channel 20, which is the radio channel to be switched to, is sent out via digital transmission path 1, base station 71, and radio channel 1. At the same time, it sends a channel switching instruction signal ■ to the base station 7□ via the signal line 2, instructing it to start up the wireless channel 2 and to monitor the synchronization of the wireless channel 2. Base station 7 that received the signal
The base station control device 11 of the base □ instructs the transmitter/receiver device 8 to activate the wireless channel 2, and also instructs the synchronization monitoring device 9 to start synchronization monitoring of the wireless channel 2.

The mobile station 2 that has received the channel switching instruction signal (2) changes the communication frequency from f to r2 based on the frequency information included in the signal. As a result, loss of synchronization occurs in the wireless channel l. Base station 7 monitoring synchronization of wireless channel 2
When the synchronization monitoring device 9 detects that the wireless channel 1 is out of synchronization, it notifies the base station control device 11 of the information. The base station control device 11 instructs the synchronization information insertion device IO,
Synchronization information indicating that out-of-synchronization of wireless channel l has occurred is inserted into digital transmission path 1. As a method for transferring information, for example, a method may be used in which a bit area for information transfer is provided in the layer 1 frame of the digital transmission path, and an indication of out-of-synchronization and establishment of synchronization is displayed in this area.

The synchronization information monitoring device 121 of the mobile switching center 6 detects the synchronization information transferred onto the digital transmission path 1, and notifies the mobile switching center control device 13 that the synchronization of the radio channel 2 has occurred.

After switching the frequency, the mobile station 2 establishes synchronization with the radio channel 2, which is the radio channel to which the frequency is switched. When the synchronization monitoring device 9 of the base station 72 detects the establishment of synchronization of the wireless channel 2,
This information is notified to the base station control device 11, and the base station control device 11 instructs the synchronization information insertion device IO to insert synchronization information indicating that synchronization of the wireless channel 2 has been established on the digital transmission path 2 into the digital transmission path 2. Insert into.

When the synchronization information monitoring device 122 of the mobile switching center 6 detects the information, it notifies the mobile switching center control device 13, and the mobile switching center control device 13, which has received the notification, instructs the switch 3 to connect the digital transmission path 1. The connection of the digital transmission line 3 is switched to the connection between the digital transmission line 1 and the digital transmission line 2.

When the mobile station 2 establishes synchronization with the radio channel 2, it sends a channel switching complete Y signal to the mobile switching center 6 via the radio channel 2, the base station 7□, and the digital transmission path 2, and the mobile switching center 6 When the signal is received, channel switching is completed.

In this embodiment, an example of channel switching during communication between different base stations connected to the same mobile switching center was shown, but channel switching during communication between base stations belonging to different mobile switching centers Even in this case, the present invention can be applied by transferring synchronization information between mobile switching centers. Of course, the present invention can also be applied to channel switching during communication between different radio channels of the same base station.

(Effects of the Invention) As explained above, by using the present invention, switch switching in a mobile switching center can be performed using the wireless channel after switching (
This can be done instantaneously upon establishment of synchronization of the wireless channel 2), and the channel switching time and instantaneous interruption time accompanying channel switching can be reduced. In addition, when switching to another wireless channel due to an error in the channel switching support signal shown in FIG. 3 or the channel switching support signal (■) shown in FIG.
This can be dealt with by monitoring the time until synchronization is established on wireless channel 2) with a timer, and instructing the user to return to the wireless channel to which the switch was made (wireless channel l) via the channel that was accidentally switched when the timeout occurs. .

Furthermore, when the present invention is applied to a channel switching method, such as that disclosed in Japanese Patent Application No. 62-001599, which realizes channel switching without interruption by changing the amount of delay using a buffer, - Buffer control can be easily performed based on the detection of synchronization establishment or the reception of synchronization loss/synchronization establishment information, and a reduction in buffer waste can be expected.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a configuration example of a digital mobile communication system when the present invention is applied, FIG. 2 is a diagram showing a configuration example of a mobile control station 1a, and FIG. 3 is a diagram according to a second embodiment of the present invention. A diagram showing an example of a sequence when a channel is switched off in a digital mobile communication system that applies a channel switching method, FIG. 4 is a diagram showing an example of the configuration of a digital mobile communication system in the second embodiment, and FIG. 5 is a diagram showing a base station 7. ．． 72 is a diagram showing an example of the configuration of the mobile switching center 6, and FIG. 6 is a diagram showing an example of the configuration of the mobile switching center 6.
8 is a diagram showing a channel switching sequence when the channel switching method in the second embodiment is implemented, and FIG. 8 is a configuration diagram of a conventional digital mobile communication method. -1- 7,,72 11-=12,. 12□ 1:l --- Mobile control station controller, mobile switching center, 111 radio base station (base station), transmitting/receiving device, 9-m-synchronization monitoring device, synchronization information insertion device, radio base station control device , 111 synchronization information monitoring device, mobile switching center control device.

Claims (1)

[Claims] Consisting of mobile stations scattered within a plurality of radio zones and at least one mobile control station or mobile switching center that transmits and receives digital signals to and from the mobile stations; In the communication channel switching method in which the switching center switches the radio channel used for communication during communication, the mobile control station or mobile switching center is equipped with a synchronization monitoring device for each radio channel and monitors the synchronization status of each radio channel before and after switching. A communication channel switching method characterized in that a mobile control station or a mobile switching center performs wireless channel switching by monitoring and taking as an opportunity the synchronization of a channel to be switched out and the establishment of synchronization of a channel after switching.