JPH0514963A - Channel changeover control system for movile object communication - Google Patents

Abstract

PURPOSE:To reduce a software processing for channel changeover in a small zone by limiting a soft processing at the time of hand over to the capture of a channel changeover trunk and executing a release autonomously by hardware. CONSTITUTION:When a movile object exists around the center of a zone a, the movile object connects with the line of the side of an opposite subscriber via a radio base station 10a and a bus 110 of a time division switch 11. When the movile object approaches an adjacent zone b, a hand over is started and the formation of buses 111, 112 inputting channel signal of each radio base station 10a, 10b in a channel changeover trunk 112 and a bus 114 performing the line connection of an opposite subscriber for the output of the trunk 12 is performed by software by controlling a switch 11. The stations 10a, 10b transmit the signal level from a movile object by adding it to a communication signal. The trunk 12 transmits a control output to a signal generation means 15 in accordance with the difference of the reception level of two radio channel signals. A termination decision means 14 selects and switches channels in accordance with the output of a level decision means 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a channel switching control system in mobile communication. In recent years, communication services for mobile terminals such as automated telephones and mobile phones have become widely used. Since such a mobile unit moves during communication, a station providing the service detects that the wireless zone boundary set in advance for each certain area has been exceeded, and controls to switch to a channel in a new wireless zone. There is a need to do. On the other hand, there is a tendency to make the wireless zone smaller due to effective use of the radio frequency used for mobile communication and miniaturization of the mobile terminal. If this is done, the control of channel switching of the wireless zone becomes more complicated, and the improvement is improved. Is desired.

[0002]

2. Description of the Related Art FIGS. 9 to 11 are views showing conventional examples.
FIG. 9 shows a state in which the mobile unit is communicating in zone A, and FIG.
Indicates the state of handover from zone A to zone B, and FIG. 11 shows communication in zone B (after completion of handover)
It is a figure showing the state of.

In FIGS. 9 to 11, 1 is a radio base station provided for each fixed area (for example, within a circle having a radius of several Km), 2 is a plurality of radio base stations 1, and they are mutually controlled. A radio line controller for transmitting and receiving signals, 3 an intra-exchange control processing unit for controlling switches of each radio line controller and an exchange, 4 a time division switch in an exchange station which is connected to each radio base station 1 and forms a communication path, Reference numeral 5 is a channel switching trunk used when communication during a call switches zones.

First, it is assumed that the mobile unit (terminal) shown in FIG. 9 is in communication in zone A. In this case, the user of the mobile unit communicates with the wireless base station 1 in zone A via one of the wireless channels, and the wireless base station 1 is connected to the exchange through the wired line L1 and time division within the exchange is performed. A communication path between a subscriber of another exchange and a user of the mobile is formed via the switch 4.

In this state, the moving body moves from zone A to zone B, and it is detected that the radio base station 1 in zone A has weakened the signal of the radio channel used until then, and the other zones are detected. The wireless base station 1 of B is in a state in which the wireless channel is detected. This state is shown in FIG. 10 as a state of handover from zone A to zone B. At this time, the wireless base station 1 in zone A and the wireless base station 1 in zone B
The wireless network control device 2 is notified of the detection information. When the radio network controller 2 transmits the status information to the intra-exchange control processing device 3, the intra-exchange control processing device 3 determines that the zone A
The line L1 connecting from the wireless base station 1 to the switching center and the line L2 connecting from the wireless base station 1 in the zone B to the switching center are connected to the channel switching trunk 5. The channel switching trunk 5 has a function of synthesizing (mixing) signals from two lines, compensating for signal level drop by combining signals from two radio base stations 1 and shifting from zone A to zone B. When switching, the communication is switched without interruption.

After the state shown in FIG. 10, the intra-exchange control processing unit 3 discriminates from the state of the signal that the mobile has completely moved to the zone B, and disconnects the connection via the channel switching trunk 5 (zone A). The connection between the wireless base station 1 and the exchange L1 is cut off, and the line L2 is connected to the other subscriber in order to connect with the communication partner only by the signal of the wireless channel between the wireless base station 1 in zone B and the mobile unit. Control to connect to the line to be connected. This state is zone B shown in FIG.
Is in communication (after completion of handover).

[0007]

The conventional acquisition and release control of the channel switching trunk described above is performed by the network (radio base station 1,
It is realized by the software of the radio network controller 2, the switching center control processor 3, etc.). On the other hand, it is necessary to reduce the zone size to increase the number of mobile terminals, effective use of radio frequency and miniaturization of terminals. It becomes frequent and complicated, the amount of software processing increases, and it may not be possible to provide services by the conventional method.

An object of the present invention is to provide a channel switching control system in mobile communication which can reduce the software processing amount for channel switching in a small zone.

[0009]

FIG. 1 is a first principle diagram of the present invention, and FIG. 2 is a second principle diagram of the present invention. In FIG. 1, 10a is a radio base station in zone a, and 10b is zone b.
Of the radio base station, 11 is a time division switch of an exchange station, 12 is a channel switching trunk, 13 is a level determination means, 14 is an end determination means, and 15 is a signal generation means.

In FIG. 2, 20 is a large zone, 2
1 is a plurality of small zones, in this example, three small zones a ...
c, 22a to 22c are radio base stations provided in each small zone, 23 is a front portion provided in the preceding stage of the communication path of the exchange,
Reference numerals 24a to 24c are addition means for adding signals of two channels, 25 is a multiplexing means, and 26 is a wireless line controller.

The first principle of the present invention is that the radio base station in each zone transmits the reception level of the signal sent from the mobile unit together with the communication signal, and the mobile unit moves from one zone where the mobile unit is located to the other zone for handover. When two wireless channels are connected to the channel switching trunk by activating, the reception level of each wireless channel is discriminated and the generation of a signal and the detection of the end of handover are performed in the wireless channel switching trunk.

The second principle of the present invention corresponds to a combination of a plurality of small zones in a large zone and a signal of a wireless channel of each small zone and all two wireless channels in each small zone. The addition output of the two channel signals is generated in advance, and one of the plurality of channels is selected at the time of handover between the small zones to switch the channels.

[0013]

In FIG. 1, when the mobile unit is located near the center of the zone a, the mobile unit is connected to the line of the other subscriber side via the radio base station 10a and the path 110 of the time division switch 11. When the mobile unit approaches the adjacent zone b, handover is started by a method similar to the conventional one, and paths 111 and 112 for inputting signals of the corresponding channels of the lines of the radio base stations 10a and 10b to the channel switching trunk 12 and channel switching. The operation of forming the path 114 for connecting the output of the trunk 12 to the line of the partner subscriber is performed by controlling the time divisional switch 11 by software.

On the other hand, the radio base stations 10a and 10b add the level of the signal received from the mobile unit as data to a communication signal (digitized signal) such as voice and transmit it through the line (whether it is always transmitted, Or transmitted at the start of handover). The channel switching trunk 12 discriminates the data of the reception level in the signals (including the reception level and the communication signal) of the two wireless channels in the level determination means, and which is larger, the difference in level is less than a certain value. It is determined whether or not the change in the identification situation is sent to the end determination means 14, and a control output indicating whether the level difference is less than or equal to a certain value or greater than the certain value is given to the signal generating means 15. Supply.

The signal generating means 15 inputs communication signals of two radio channels and adds the two signals (mixing).
And a communication signal of the zone a (when the signal of the zone a is large and the level difference exceeds a certain value) by a control signal from the level determination means 13, and an addition output signal of the two communication signals (level difference). Is below a certain value) and zone b
Communication signal (when the signal in zone b is large and the level difference exceeds a certain value), any one of the three is selected.

The end judging means 14 is a level judging means 13
When the output history of 1 is judged and it is found that the reception level of zone b has exceeded a certain value, a control signal indicating the end of handover is notified to a control unit (not shown). As a result, the path 113 of the time division switch 11 is formed and the channel switching trunk 12 is opened.

In this way, the operation of selecting a channel in the channel switching trunk and the operation of opening the channel switching trunk at the time of handover are autonomously performed by hardware.

Next, referring to FIG. 2, the respective radio base stations 22a to 22a provided in the three small zones a to c in the large zone 20.
Each radio channel signal from 2c is input to the front section 23 provided in the preceding stage of the time division switch of the exchange. The front-end portion 23 generates three independent signal outputs of the zones a to c as channels 0 to 2 (Ch0 to Ch2), and three addition means for combining and adding the two signals of the zones a to c. 24a to 24c.

The three adding means 24a to 24c respectively add the outputs of the zones a and b, add the outputs of the zones b and c,
Generates the summed outputs of zones c and a, and outputs them to channel 3 respectively.
.About.5 (Ch3 to Ch5). The signals of these respective channels are multiplexed by the multiplexing means 25 and supplied to a time division switch (not shown). The wireless line control unit 26 monitors the moving body during handover, controls the wireless base station, and transmits / receives control information to / from the switching center.

In this configuration, when a mobile unit is located in the small zone a within the large zone 20 and is communicating with the other party, the radio channel signal between the radio base station 22a and the mobile unit is set in the front section. It is input to the switch of the exchange through channel 0 of 23 and connected to the other subscriber (including other exchanges). When this mobile unit starts to move from the small zone a to the small zone b, the change in the signal level of the wireless base stations 22a and 22b in each small zone is monitored by the wireless line control unit 26 and the control unit (not shown) of the exchange. ) Will be notified. The control unit knows that a handover has occurred between the small zone a and the small zone b, and a channel constituted by a signal obtained by adding the signals of the small zone a and the small zone b out of the channels generated by the front portion 23. Three
Select to control the connection to the other subscriber.

When the wireless line control unit 26 detects the completion of the handover by the change in the signal level of the wireless base stations 22a and 22b, the control unit uses the channel generated in the front unit 23 as the wireless channel used by the mobile unit. Only 1 (radio channel of small zone b) is selected. For handover between large zones, the channel switching trunk is used as in the conventional method.

As described above, the handover between the small zones in the large zone does not use the channel switching trunk, so that the software processing can be simplified.
In the principle diagram of FIG. 2, a multiplexer 25 is provided in the front part 23 and a plurality of outputs of channels Ch0 to Ch5 are multiplexed and sent to a time division switch. However, a selector is provided instead of the multiplexer 25. It is also possible to receive a control signal from a control unit (not shown), select one of Ch0 to Ch5, and supply only the selected channel signal to the time division switch.

[0023]

3 to 5 show an embodiment corresponding to the first principle, and FIGS. 6 to 8 show an embodiment corresponding to the second principle.

FIG. 3 is a system configuration diagram of the first embodiment, FIG. 4 is a configuration diagram of the channel switching trunk according to the embodiment, and FIG. 5 is a first embodiment.
6 is a system configuration diagram of the second embodiment, FIG. 7 is a configuration diagram of the front part of the embodiment, and FIG. 8 is an example of the operation sequence of the second embodiment.

FIG. 3 shows an example of managing communication for the four zones a to d, 30 is a radio base station provided in each of the zones a to d, 31 is a radio base station for monitoring and controlling each radio base station, A radio line controller controlled by the central control unit of the exchange, 32 is a line interface connected to each radio base station by a line for communication, 33 is a time division switch of the exchange,
Reference numeral 34 is a channel switching trunk having the configuration according to the present invention, 35 is a network controller (indicated by NWCTL) for controlling the time division switch, and 36 is a central controller (C).
C) and 37 are public network interfaces.

The channel switching trunk 34 shown in FIG.
The configuration of this embodiment is shown in FIG. In the example of FIG. 4, a case where signals of one pair (two channels represented by Fa and Fb) to be handed over are input will be described. However, in reality, multiplex processing is performed on inputs of a plurality of pairs.

The symbols used in FIG. 4 are explained below. Fa, Fb: Received data IN from the line interface (HWIF) 32 connected to the zones a and b: Received data from the public network subscriber CTL: Control data from the central controller CC END: To the central controller CC Handover completion display OUT: Transmission data Ba to public network subscribers Ba, Bb: Transmission data to each line interface connected to zone a and zone b DATA: Handover completion information to be transmitted to NW control unit Each part of FIG. 4 will be described. Then, 40 computes the level information of the reception data Fa and Fb of the two channels, and if both levels are small, it is in an unused state, if only one is large, it is before or after handover, and if both are large, it is an output indicating that handover is in progress. The state determination unit 41 that generates a signal manages the history of information of the state determination unit 40, and ends the handover. It is a handover end determination unit that determines completion.

Reference numeral 42 indicates a handover end display from the output information of the handover end determination unit 41, and a handover end display unit that returns the end display in the reading order of the central control unit (CC). Reference numeral 43 indicates the output information of the state determination unit 40. It is a signal generation unit that selects a signal obtained by adding signals Fa and Fb during a handover and selects a signal having a higher level before and after the handover and sends it as an output signal (indicated by OUT).

Reference numeral 44 denotes a distributor for distributing a signal sent from a communication partner (digital signal such as voice, which is the content of communication) to the zones a and b in order to send it to the mobile unit, and 45 denotes a signal from the central controller (CC). An order distributing unit that distributes the order (reading the handover status, notifying NW (time division switch) compatible channel numbers of Fa and Fb, etc.), and 46 is an NW compatible channel number of Fa and Fb received from the order distributing unit 45. Is a data output unit that transmits to the NW control unit when the handover end determination unit 41 receives the handover end information. The operation of the system configuration of FIG. 3 using the channel switching trunk having the above configuration will be described with reference to the operation sequence example shown in FIG.

First, the mobile unit is the radio base station 3 in the zone a.
0, the line interface (HWIFa) 32, the time divisional switch (NW) 33, and the public network interface 37 to communicate with the other party connected to the public network.

When a mobile unit moves between zone a and zone b during communication, a handover request is issued from the radio network controller 31 that monitors the radio base stations 30 in zones a and b, and the central controller (CC) ) 36 (FIG. 5). This causes the central control unit to have two line interfaces (HWIFa, HWIF) connected to the zones a, b.
The communication channel assigned to this mobile unit of the IFb) 32 is changed to the channel switching trunk 34 (CXT in FIG. 5).
NW control unit 35 (NWC in FIG. 5) so that the public network interface 37 of the mobile communication partner is connected to the output side of the channel switching trunk 34.
(Displayed by TL) (in FIG. 5). NW control unit 35
This allows two line interfaces (HWIFa,
The channel of the public network interface 37 connected to HWIFb) is stored as a pair. Also, the channel switching trunk (CXT) is notified of the NW compatible channel numbers of the two communication channels (channel numbers assigned to the highway that transmits the multiplexed signal of the time division switch to the radio channels Fa and Fb). (Fig. 5).

Thus, the received data F of the corresponding channel number
a and Fb are connected to the channel switching trunk shown in FIG. 4 (34 in FIG. 3), handover is started, and only one large signal or two signals are added depending on the signal levels of the two channels. The output signal thus obtained is selected and an output signal to be sent to the communication partner is generated.

After this, when the handover is completed, FIG.
Handover end determination unit 41 of the channel switching trunk of
Is displayed by the handover end display unit 42, and the handover end information from the handover end determination unit 41 is displayed on the data output unit 46.
Sent to. Then, the data output unit 46 notifies the NW control unit (35 in FIG. 3) of an instruction to release the NW corresponding channel numbers Fa and Fb (in FIG. 5).

Upon receiving this notification, the NW control section receives the notification, and the line interface (HWIFb) and the public network interface 37 of the destination (zone b) stored at the start of the handover.
Connect.

The software in the central controller CC recognizes at the time of handover, but not at the time of termination. However,
Since it is necessary to manage the usage status of the channel switching trunk, scan processing is performed asynchronously with communication to understand the usage status of the channel switching trunk. This operation is shown in FIG.
When the handover status reading order is sent from the central control device CC to the channel switching trunk at, the operation corresponds to the operation of returning the end display information if the handover is completed at that time (in FIG. 5). To explain this mechanism with the configuration of FIG. 4, when the order distribution unit 45 receives a read order in the handover state from the central control device CC, the order is distributed to the handover end display unit 42. Then, the handover end display unit 42 returns the display contents at that time (indicating whether or not the display is the end) to the central control device CC.

The wireless line control device (31 in FIG. 3) monitors the handover and controls the wireless base station (30 in FIG. 3) with the same function as before. However, since the software of the central controller CC of the exchange does not need to recognize the end of the handover, it is not necessary for the radio network controller to notify the exchange of the termination information.

Next, the configuration of the second embodiment will be described with reference to FIGS. In the system configuration of Example 2 of FIG. 6,
There are A, X, Y, etc. as large zones, and each large zone is divided by a small zone having a smaller radius. In this example, only the large zone A is shown, and small zones a to d are provided as shown in the figure. Has been.

A radio base station 60 is provided corresponding to each small zone, each radio base station is connected to a radio line controller 61 by wire, and the radio line controller 61 is a controller 6 of the exchange.
4 (including the central control device CC and the NW control device). The line connecting the radio base station 60 and the exchange in each small zone is accommodated in the front device 62 (including the front unit 23 of FIG. 2) of the time division switch 63. Time division switch 63
A channel switching trunk 65 for performing a handover between large zones, a public network interface 66 for connecting to a subscriber of a communication partner, and the like are connected to the same.

The configuration of an embodiment of the front device 62 of FIG. 6 is shown in FIG.
Shown in. In FIG. 7, reference numeral 620 denotes a line interface (HWIFa) that connects to each radio base station in each of the small zones a to d.
˜HWIFd), 621 is a combination of communication channels of each line interface (a and b, a and c, a and d, b).
And c, b and d, and 6 sets of c and d). The signals independently generated from each line interface 620 are output as channels 0 to 3 corresponding to the small zones a to d, and the signals of the six adder circuits 621 are output as channels 4 to 9. These signals are multiplexed (multiplexer is not shown)
Then, it is input to the time division switch 63 of FIG.

FIG. 8 shows an example of an operation sequence of each part having the configuration of the second embodiment shown in FIGS. 6 and 7. First, a mobile unit located in the small zone a passes from the radio base station 60 to the public network interface 66 via the channel 0 (FIG. 7) of the line interface (HWIFa) 620 of the front device 62 and the time division switch 63. Assume that you are communicating with the other subscriber connecting to. After that, when the mobile unit moves to the small zone b, the wireless network controller 61 that monitors the wireless base station 60 issues a handover request between the zones a and b to the controller 64 (in FIG. 8). .

As a result, the control device 64 selects the channel 4 (addition output of the signals of the zones a and b) from the line in which the channels 0 to 9 input from the front device 62 to the time division switch 63 are multiplexed. Control to connect to the public network interface 66 (FIG. 8). As a result, the state of handover is in progress.

After that, when the wireless link control device 61 notifies the control device 64 that the moving body has moved to the small zone b and the handover is completed (FIG. 8), the control device 64 causes the front device 62 to The channel 1 (communication channel of the small zone b) is selected from the plurality of output channels and connected to the public line interface 66 (FIG. 8). After this, the end device sends the end information to the control device (FIG. 8). In this case, the front device does not control anything.

In the above embodiment, the control device selects one channel from the multiplexed channels 0 to 9 generated in the front device, but the front device selects one channel. It is also possible to provide a means for selecting the corresponding channel by the front device in response to a channel selection instruction from the control device.

Next, the radio circuit controller 61 of the large zone A
(FIG. 6) and when a handover between large zones is requested from a wireless line control device (not shown) in the large zone X (FIG. 8), the same processing as in the conventional case is performed. That is, the control device connects the channels assigned to the mobiles in the large zones A and X to the channel switching trunk (FIG. 8), notifies the end of handover (FIG. 8), and notifies the channel switching trunk of the end. Then (same), the termination information is returned from the channel switching trunk (same ').

[0045]

According to the invention of the first principle of the present application, since the soft processing at the time of handover is limited only to the acquisition of the channel switching trunk and the opening is autonomously executed by the hardware, the soft processing in the exchange can be performed. Since the load can be reduced and the processing capacity is increased, it is possible to deal with small zone configurations.

Further, according to the invention of the second principle, the software processing in units of small zones is limited to the channel selection, so that the resource management processing of software can be reduced and the small zone configuration can be dealt with.

[Brief description of drawings]

FIG. 1 is a first principle diagram of the present invention.

FIG. 2 is a second principle diagram of the present invention.

FIG. 3 is a system configuration diagram of the first embodiment.

FIG. 4 is a configuration diagram of an embodiment of a channel switching trunk.

FIG. 5 is an example of an operation sequence of the first embodiment.

FIG. 6 is a system configuration diagram of a second embodiment.

FIG. 7 is a configuration diagram of an embodiment of a front portion.

FIG. 8 is an example of an operation sequence of the second embodiment.

FIG. 9 is a diagram showing a state during communication in zone A of the conventional example.

FIG. 10 is a diagram showing a state of handover from zone A to zone B in the conventional example.

FIG. 11 is a diagram showing a state in which communication is being performed in zone B of the conventional example (after completion of handover).

[Explanation of symbols]

10a Wireless base station in zone a 10b Zone b wireless base station 11 Time-sharing switch of exchange 12-channel switching trunk 13 Level judgment means 14 Termination determination means 15 Signal generation means

Claims (3)

[Claims] 1. In a channel switching control system for mobile communication, when a mobile moves from one zone to another, the exchange station inputs the radio channel signals of the two zones and outputs them to the line of the other subscriber. And a channel switching trunk for supplying the data, the channel switching trunk receives a communication signal and a reception level data from a wireless base station of each zone to determine two levels, and the two wireless channels are determined based on the level determination result. And 2
One of the signals obtained by adding the two radio channels is selected and output, and handover end information is generated according to the progress of the level judgment, and the control unit of the exchange confirms that the channel switching trunk is opened by the end information. A channel switching control method for mobile communication. 2. In a channel switching control method in mobile communication, a large zone is composed of a plurality of small zones, handover processing between the large zones is performed via a channel switching trunk, and small zones within the large zone are connected. The handover is performed by selecting one of a plurality of small zone signals generated in the front part provided in the preceding stage of the call switch of the exchange station or a combination of two small zone signals. A channel switching control method for mobile communication. 3. The front part according to claim 2, wherein the front part inputs a channel signal from each small zone in the large zone and outputs a channel signal corresponding to an individual zone and two channel signals from each zone. Each adding means for adding corresponding to a different combination; and a multiplexing means for multiplexing the channel signals corresponding to the individual zones and each channel signal generated from each adding means and outputting the multiplexed signals to the communication path switch. A channel switching control method for mobile communication.