JP2595893B2 - Digital mobile communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital mobile communication system, and more particularly to a digital mobile communication system constructed using a public network.

[0002]

2. Description of the Related Art Hitherto, there has been proposed a digital mobile communication system such as a portable telephone system for transmitting a digitized signal through a wireless line in a time-division manner using a public network. FIG. 12 is a configuration diagram showing a mobile communication system in which a higher-level connecting device of each base station is connected to a public network (for example, Japanese Patent Application Laid-Open No. 2-216923). In the figure, reference numeral 805 denotes a mobile station, 831, 832
Is a connection device for directly accommodating the wireless base stations 811 to 813 and 821 to 823 in a star shape, respectively.
4 and connected to the general subscriber terminal 806, and the database 807 via dedicated lines 841 and 842.
It is connected to the.

Each of the connection devices 831 and 832 is a device equivalent to a private branch exchange, and each of the subordinate wireless base stations 811 to 813.
One private cordless telephone system is configured by controlling each of the local cordless telephones 821 to 823, and connected to the public network 804 to connect to the subscriber terminal 806 of the public network 804. The systems are combined to expand the coverage area. For the mobile station 805 during a call, when moving within the area of each local cordless telephone system, the radio base stations 811 to 813 and 821 to 8 which receive communication services.
23 is controlled by a higher-level connection device 831, 832 to maintain the call. When the mobile station 805 moves between the above-mentioned local cordless telephone systems, the mobile device 805 is provided in the connection device 831, 832. Public network 804
The call is transferred between the systems by the transfer function of the database and the movement management function of the database 807, so that the call can be continued.

[0004] FIG. 13 shows that a radio base station is connected to a public network as a general subscriber, and a busy telephone call receiving service function (commonly called a call waiting service) of an ordinary telephone exchange is used without using an exchange exclusively for a car telephone. FIG. 1 is a configuration diagram showing a mobile communication system using the same (for example, Japanese Patent Application Laid-Open
-84327). In the figure, 951, 961
Have wireless zones 950 and 960, and are connected to the exchange 920 in the terminal station 910 via the public network 940, and 952 and 962 are mobile stations in each wireless zone.
Is a subscriber terminal group composed of general subscriber terminals 931 to 93n connected to the exchange 920 via the public network 940.

[0005] Since the radio base stations 951 and 961 have the same function as the radio base station of a car telephone, the movement of the mobile stations 952 and 962 within the radio zones 950 and 960 can be reduced by the ordinary car telephone. A communication service equivalent to that of a network can be provided. When a mobile station 951 during a call needs to change the radio base station 951 to receive the communication service due to geographical movement, the communication service is provided. The wireless base station 951 warns the mobile station 952 with an alarm sound or the like. When a person who is talking on the mobile station 952 wants to continue the call, the mobile station 952 performs a predetermined operation to switch the wireless base station to the wireless base station 951 that originally received the call service. A signal is sent to hold the public line between the wireless base station 951 and the communication partner.

[0006] Subsequently, the mobile station 952 searches for a wireless base station, eg, 961, which can receive the communication service next, designates the telephone number of the other party who originally talked to this station, and automatically makes a call. Perform processing. The radio base station 961 that has received the call signal makes a call to the public network with the designated telephone number, but on the assumption that the designated communication partner has subscribed to the call waiting service, the mobile station 952 Recognizing that the mobile station has received the service during the call with the base station and has switched the radio base station, switches to the call via the radio base station 861 in accordance with a predetermined hooking operation by the communication partner, and continues the call. Will be able to

[0007] On the other hand, RCR STD-28, which is a standard of the second generation cordless telephone system, specifies a call processing sequence. Hereinafter, parts related to the present invention will be described with reference to FIGS. . Note that RCR STD-28 defines an interface in a wireless section between a wireless base station and a mobile station in a second generation cordless telephone system, and recommends a method for transmitting digitized signals in a time-division manner. I have.
FIG. 14 is a sequence diagram showing a calling sequence by batch calling between the mobile station (PS) and the radio base station (CS).

First, the radio base station uses a broadcast channel B
The CCH broadcasts control information m11d such as system information and channel structure information.
If the reception level of the radio wave transmitting the CH is checked and it is determined that access is possible, SCCH information as a control channel specific to each radio base station is obtained from the content of the received BCCH. In order to know a control channel and a communication channel to be used when a future call processing sequence is advanced to a radio base station using an available uplink SCCH in response to a call operation by a mobile station designating a communication partner number. Sends a link channel establishment request signal m12u to the base station, and the radio base station transmits a link channel assignment signal m12d on the downlink SCCH.
And notifies the mobile station of FACCH / SACCH information of a control channel to be used in a subsequent call processing sequence and TCH information of a communication channel.

Next, the mobile station exchanges synchronization burst signals m13u and m13d with the radio base station using the designated time slot of the designated radio channel to perform synchronization necessary for transmission and reception of digital signals. Through this process, a layer 1 for transmitting and receiving signals to and from the subsequent FACCH / SACCH / TCH is established. Subsequently, the mobile station moves to a layer 2 connection procedure, and performs uplink FACCH and SA
A SABM signal m14u is transmitted to both CCHs, and the radio base station transmits a UA signal m to both the down FACCH and the SACCH.
FACCH and SACCH by returning 14d
Establishes both layer 2 logical links, so that layer 3 call processing signals can be transmitted and received on either link.

[0010] Next, the mobile station transmits a call setup signal m15u belonging to the CC sublayer of layer 3 to the uplink SACCH or F
The data is transmitted to the radio base station on the ACCH to notify the communication partner of the mobile station to the network side. Thereafter, layer 3 signals m15d to m19 related to mobility management and radio management between the mobile station and the radio base station.
d is exchanged on the SACCH or FACCH, and the mobile station is authenticated by the radio base station (m20d, m20u).
Is completed, the DISC signal m21 from the radio base station
By transmitting d and returning the UA signal m21u from the mobile station, the link of the FACCH is disconnected, and the subsequent call control signals are performed only on the SACCH.

On the radio base station side, after the authentication work of the mobile station is completed, the mobile station proceeds with the call connection processing with the communication partner requesting the connection, and when the network side calls the communication partner,
Layer 3 C on the SACCH to the mobile station via the radio base station
While transmitting the call signal m22d of the C sublayer,
A ringback tone signal m23d indicating that a call is being made from the network side is sent out, so that a person using the mobile station can hear it. When the communication partner answers the call, a response signal m24d of the layer 3 CC sublayer is transmitted from the network side to the mobile station via the radio base station, and the mobile station uses the designated communication channel, TCH, to make a call. Will be able to

FIG. 15 shows a radio base station (CS) in the communication channel switching sequence of RCR STD-28.
FIG. 10 is a sequence diagram showing a call processing sequence in the case of switching between the switching modes and a recalling type with a mobile station (PS) request. The mobile station during communication constantly monitors the reception level and the reception quality (bit error rate) of the radio base station receiving the communication service, and utilizes the idle time during which no burst signal is transmitted or received. The reception level of the BCCH transmitted by a radio base station other than the receiving radio base station and the identification number of the radio base station are constantly monitored.

Here, when the mobile station detects the deterioration of the reception level or the deterioration of the reception quality of the radio base station receiving the communication service, the mobile station has established as a logical link together with the communication channel TCH. F of control channel
A TCH switching request signal m31 of the layer 3 RT sublayer to the radio base station via the ACCH or the SACCH.
By sending u, the identification number of the wireless base station desired as the switching destination can be notified with one or more priorities.

The TCH switching request is transmitted to the network side via the switching source radio base station, and the network side selects one of the optimum radio base stations to be switched to and selects the switching source. TCH of the layer 3 RT sublayer via the base station
The switching instruction signal m31d is transmitted to the requesting mobile station by FACCH or SACCH to notify the information of the wireless base station of the switching destination. Thereafter, the mobile station issues the TCH switching instruction (m
31d), the radio base station indicated in FIG.
4 (m12u to m24)
d), the procedure (m22d, m2) related to the calling
Except for 3d), call processing is performed in substantially the same procedure (m32d to m41d), and switching of the radio base station can be performed.

[0015]

Therefore, such conventional mobile communication systems have the following problems, respectively. First, in the mobile communication system (see FIG. 12) in which the higher-level connecting device of each base station is connected to the public network as described above, the connecting devices 831 and 832 are functionally exchanged in the mobile telephone network. Although there is no substantial difference from the dedicated exchange which performs the call, since the respective cordless telephone systems are connected via the ordinary public network 804, the call transfer processing is performed according to the protocol of the public network 804 as follows. There are various restrictions on communication services. First, in this mobile communication system, since the protocol of the public network 804 is an individual signal line system, when a call transfer process becomes necessary, a transfer communication line with the transfer destination connection device 832 is established. There has been a problem that the securing and the transfer of the call cannot be separated and are performed at the same time, and during the transfer process, a time during which the call cannot be made with the other party occurs.

Second, since the means for transmitting the radio channel information to be switched between the different connection devices 831 and 832 is not supported by the ordinary line signal system of the ordinary public network 804, the ordinary telephone transfer processing alone is not sufficient. The transfer of the wireless channel switching information cannot be realized, and the communication partner of the mobile station 805 to be transferred specifies the transfer destination connection device 832 in a complicated manner, or usually, information of the mobile subscriber itself or location registration information, etc. The database 807 responding to the inquiry of (1) needs to have a function of accumulating wireless channel information during communication and transferring wireless channel switching information between wireless base stations, and the frequency of accessing the database increases. there were.

In addition, as described below, the mobile station is connected to the public network as a general subscriber, and the mobile phone uses the call waiting service of the ordinary telephone exchange without using the exchange dedicated to the car telephone. Communication system (Fig. 1
3), the first is that the functional elements that correspond to the connection devices 831 and 832 in the mobile communication system of FIG. 12 and that collectively manage the respective radio base stations and perform call control are missing in the mobile communication system. In order to switch between the radio base stations 951 and 961, a person who is talking on the mobile station is requested to operate the mobile station 952, and the communication partner of the mobile station 952 is conscious of the change of the radio base station being talked on. The system is designed to reduce the economic burden of the system by imposing a burden on the user in terms of the convenience of the call that requires the user to perform the operation.
The price reduction effect of the system is limited only to the dedicated exchange part of the car telephone network, so the radio base station that occupies most of the system price is not different from that of the car telephone network, so there is not much price reduction effect. Unexpected, the inconvenience of the call has become noticeable.

Second, such a system lacks a database function to be shared by the radio base stations, which is indispensable for managing the information of the mobile station itself and the location of the mobile station. Will individually manage subscriber data, and since the radio base station itself is a subscriber of the public network, when calling a mobile station, the calling party must identify the radio base station where the mobile station is likely to be located. There is also a fatal problem that a call must be specified. In addition, in order to improve the convenience of incoming calls to mobile stations, it is necessary to increase the size of the radio base station. In this system, however, the radio base station must be made smaller in order to improve the use efficiency of radio frequencies. This is a countermeasure against the current technology trend of trying to reuse radio frequencies, and has been a problem in terms of radio wave usage and subscriber capacity.

Further, regarding the call processing sequence of RCR STD-28 which is a standard of the second generation cordless telephone system, a signal obtained by digitizing a signal digitized in a radio section with respect to switching of a radio base station for a mobile station during a call is time-division. In addition to adopting a transmission method, the processing load on the network side is reduced because the mobile station specifies the wireless base station of the switching destination, but the wireless base station of the switching destination is high. When the mobile station is operated in the traffic state, it is considered that there is a possibility that the mobile station may fail to switch due to the reason for the switching destination radio base station such as the TCH being full at the switching destination radio base station during the switching process. Can be

In particular, in the second-generation cordless telephone system, since the number of channels handled by one station is reduced, and a large number of wireless base stations for miniaturizing the device and the service area of one station are arranged, the wireless base station Although the probability of operation in a high-traffic state is very high, and the switching process of the radio base station is considered to occur frequently due to the small service area of one station, the above-mentioned danger is nevertheless low. There was no problem. The present invention is intended to solve such a problem, and realizes a flexible connection between a radio base station and a call connection processing device, thereby reducing the economical burden required for system construction and reducing It is an object of the present invention to provide a digital mobile communication system capable of automatically and securely switching a radio base station in response to the request.

[0021]

In order to achieve the above object, a digital mobile communication system according to the present invention comprises a plurality of radio base stations connected to a public network as subscribers, and a subscriber to a public network as subscribers. It is connected by providing a call connection processing means for controlling the call connection to the mobile station, a radio base station
Is established via a public network in response to a call connection request from a mobile station.
A call is made to the fixed call connection processing means, and
Public network from the wireless base station in response to the wireless base station switching request of
The switching request is transferred to the corresponding call connection processing means via
The connection processing means is connected to a public network in response to a call from a wireless base station.
A connection to the other party via the
Incoming calls from wireless base stations and outgoing calls to communication partners
To establish communication and switch from the wireless base station.
New wireless base station and mobile station via public network upon request
After establishing a communication line, the communication line
The communication line is switched and connected . Also,
Each wireless base station has, as system information constantly broadcast to a mobile station through a predetermined wireless channel, identification information for identifying the own station and a line assignment indicating whether or not a wireless channel capable of newly establishing a call connection within the own station is possessed. When the mobile station detects deterioration of the radio wave reception state during communication with the first wireless base station, the mobile station transmits the state information and the other wireless base station using the idle time of the time division communication. A plurality of radio base stations are prioritized and selected according to the reception level of the radio wave broadcasted from and the identification information and the line allocation state information in the received system information, and each of the selected radio base stations is selected. Is transmitted to the first radio base station as a switching candidate, and the first radio base station sends the switching request to the call connection processing means to which the mobile station is connected. Call via the Means for transmitting, via a public network, a request for securing a wireless channel to each wireless base station based on the priority in response to an incoming call based on the switching request, and a second wireless base station among the wireless base stations , The communication partner of the mobile station and the second wireless base station are communicated with each other in accordance with the establishment of a wireless channel between the mobile station and the second wireless base station using the secured wireless channel. And if the wireless channel between the mobile station and the second wireless base station has not been established, or if no wireless base station has returned the channel reservation completion, The communication with the first wireless base station is restored. Further, the second wireless base station secures an empty wireless channel in response to the channel securing request from the call connection processing means and returns the completion of channel securing, updates the line allocation state information in the system information, A radio channel with the mobile station is established by a radio channel secured in response to a call from the mobile station within a predetermined time from the update of the allocation state information, and the mobile station performs call connection processing via the first radio base station. In response to the switching destination radio base station information to which the second radio base station is to be switched, transmitted from the means, the line allocation status information from the second radio base station is ignored and the transmission to the second radio base station is performed. It is intended to be called. In addition, a database means for connecting to a predetermined dedicated line network and managing location registration information and subscriber information relating to all mobile stations as mobile station management information is provided, and all call connection processing means are provided with a predetermined dedicated line network. It is connected to the line network, acquires necessary mobile station management information from the database means, updates the mobile station management information in the database means, and performs various calls with other call connection processing means via the dedicated line network. The control information is exchanged.

[0022]

Therefore, in response to a call connection request from the mobile station, a call is made from the radio base station to any call connection processing means via the public network, and the call connection processing means communicates with the communication partner via the public network. A communication line is established, and the switching request is transferred from the wireless base station to the corresponding call connection processing unit via the public network in response to the switching request for the wireless base station from the communicating mobile station,
The connection is switched to a communication line between the new radio base station and the mobile station via the public network by the call connection switching means. When the mobile station communicating with the first wireless base station detects deterioration of the radio wave reception state, a plurality of radio stations selected by prioritizing according to the radio wave reception level and the line allocation state information are determined. A request to switch the radio base station is transmitted from the mobile station with the base station as a switching candidate, and in response to an incoming call from the radio base station via the public network based on the switching request, each The wireless base station is requested to secure a wireless channel and establish a wireless channel with the mobile station, and a call connection switching process is performed according to the wireless channel establishment. Further, in the second radio base station selected as the switching destination, in response to a channel reservation request from the call connection processing means, a channel is allocated before a radio channel is established before establishing a radio channel with the mobile station. In response to a call from the mobile station within a predetermined time after the update of the status information and ignoring the channel allocation status information of the second wireless base station, a wireless channel with the mobile station is established by the reserved wireless channel. Further, the database means is accessed from all the call connection processing means via the dedicated line network, and various pieces of call control information are exchanged with other call connection processing means.

[0023]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing a mobile communication system according to a first embodiment of the present invention.
Is a wireless base station connected as a subscriber to the public network 104 via the communication lines 101a and 102a and data lines 101d and 102d, and 103 is a subscriber as well as the communication lines 103a, 103b and 103e and the data line 10
A call connection processor connected to the public network 104 via 3c and 103d, 105 is a mobile station, and 106 is a general subscriber terminal.

Now, the mobile station 105 is in a state of talking with the subscriber terminal 106 of the public network 104 via the radio base station 101, and the radio base stations 101 and 102 transmit the call control information to the call connection processing device. Data line 1 for communicating with 103
01d and 102d, and communication lines 101a and 102a for assigning the mobile station 105 as a communication path.
It is connected to the public network 104, and the call connection processing device 103 is similarly connected to the public network 104 via the communication lines 103a and 103b and the data lines 103c and 103d.

FIG. 3 is a block diagram showing the call connection processing device 103. In the figure, reference numerals 201a to 201m denote communication lines 103a, 103b, 103 from the public network 104.
e, etc., and a subscriber circuit 206a-206n for connecting and processing speech path signals exchanged between the radio base stations 101 and 102 and the subscriber terminal 106;
4 to accommodate data lines 103c, 103d, etc.
A data line connection circuit for connecting and processing call processing control signals exchanged between the radio base stations 101 and 102 and another call connection processing device; 203a to 203j are tone generation circuits for generating call processing tones; 204k is a tone receiving circuit for receiving and identifying a call processing tone;
Reference numerals a to 205n denote data link processing circuits that logically terminate the data lines 103c and 103d by transmitting and receiving predetermined call processing control signals.

Reference numeral 202 denotes subscriber circuits 201a to 201m
And a tone generating circuit 203a-203j or a tone receiving circuit 203a-203k, and a data division connecting switch 206a-206n and a data link processing circuit 205a-205n. The connection between the connection circuits 206a to 206n and the data link processing circuits 205a to 205n establishes a call processing data link with the wireless base stations 101 and 102 or another call connection processing device via the public network 104. The data line 103c and others are physically (electrically) terminated by the data line connection circuits 206a to 206n, and logically terminated by the data link processing circuits 205a to 205n.

Reference numeral 207 denotes a control circuit for controlling the entire call connection processing apparatus 103, and includes subscriber circuits 201a to 201m.
Transmission / reception of call processing signals to / from, tone transmission circuits 203a to 203a-2
03j and the tone receiving circuits 204a to 204k, the time division switch 202, the monitoring and control of the data line connection circuits 206a to 206n, and the transmission and reception of call control signals to and from the data link processing circuits 205a to 205n. In addition to performing processing, it connects to a database device 501 or another call connection processing device described later via a dedicated line accommodated in the dedicated data line connection circuit 208, and manages the mobile station such as the location of the mobile station and subscriber information. Information is immediately obtained and updated to deal with the wide-area movement of mobile stations.

FIG. 4 is a block diagram showing the radio base station 101 (102). In FIG.
p accommodates the communication line 101a (102a) and
4, a subscriber circuit having a busy tone detection function while connecting a call path signal with the call connection processor 103, and 302a to 302p encoding / decoding circuits,
03 is a time-division switch, 304a to 304q are modulation / demodulation circuits, and 306 is an antenna. The speech path signals from each speech line are received by subscriber circuits 301a to 301p and encoded by encoding / decoding circuits 302a to 302p. And multiplexed by the time-division switch 303 to form a modulation / demodulation circuit 304a.
To 304q, and vice versa.
The signal from 4q is separated by the time division switch 303, decoded by the encoding / decoding circuits 302a to 302p, and then output to each communication line as a communication path signal via the subscriber circuits 301a to 301p.

The radio frequency signals between the modulation / demodulation circuits 304a to 304q and the antenna 306 are exchange-connected in a time division manner by a time division switch 305. Also, 30
8 accommodates the data line 101d (102d) and
A data line connection circuit for connecting and processing a call processing control signal to and from the call connection processing apparatus 103 via the communication line 04; a data link processing circuit 309 for logically terminating the data line 101d (102d); A control circuit for controlling each circuit in (102) to perform call processing, and includes a data link processing circuit 309 and a data line connection circuit 30
8, the call connection processing circuit 103 via the public network 104
And a data link between the base station and another wireless base station.

FIG. 5 is a block diagram showing the mobile station 105. Reference numeral 401 denotes an audio processing circuit for converting a user's voice into an electric signal, and reference numeral 402 denotes an encoding circuit for encoding a signal from the audio processing circuit 401. And 403, a modulation circuit for modulating the coded signal from the coding circuit 402 into a radio signal, 406 a demodulation circuit for converting the radio signal received by the antenna 405 into an electric signal, and 407 a signal for decoding the signal from the demodulation circuit. A decoding circuit 404 outputs the signal from the modulation circuit 403 to the antenna 405 and outputs a signal received from the antenna 405 to the demodulation circuit 40.
Reference numeral 408 denotes a control circuit for controlling each circuit in the mobile station for call processing and status monitoring.

The voice from the user is processed by a voice processing circuit 401,
Encoding circuit 402, modulation circuit 403, time division switch 4
, A radio wave transmitted from the antenna 405 via the antenna 405, and a radio wave received by the antenna 405 are transmitted through the time division switch 404, the demodulation circuit 406, and the decoding circuit 40.
7. Converted to an audio signal via the audio processing circuit 401,
It is output as voice to the user.

FIG. 9 is a block diagram showing a call control information transmission system in the mobile communication system of the present invention. In FIG. 9, reference numeral 501 denotes various information necessary for call control of the mobile communication system, for example, call control information, mobile station. A database device for centrally storing and managing location registration information and inquiry / response information of mobile station management information, etc., 502 is a database device 501 and call connection processing devices 503a to 503c (FIG. 1).
505a, a data exchange device for establishing a dedicated line network by connecting the dedicated call control processing device 103) with a dedicated line.
To 505e are radio base stations (the radio base stations 101 and 1 in FIG. 1).
02), 506a and 506b are wireless mobile stations (FIG. 1).
Corresponding to the wireless mobile station 105), and the call connection processing device 5
03a to 503c and wireless base stations 505a to 505e
Are connected to the public network 504 as general subscribers.

FIG. 10 is a block diagram of the database device 501. In FIG. 10, reference numerals 601a to 601r denote data line connection circuits accommodating a dedicated line from the data exchange device 502, and 602a to 602r denote data lines via the respective dedicated lines. A data link processing circuit for logically terminating the data link, 6
04, a storage device for storing various call control information;
Reference numeral denotes an arithmetic processing circuit for performing a response / update process to an inquiry or instruction from the call connection processing devices 503a to 503c based on various types of call control information stored and stored in the storage device 604.

FIG. 11 is a block diagram of the data exchange device 502. In FIG. 11, reference numerals 701a to 701r denote database devices 501 or call connection processing devices 503a.
, 702a to 702r are data link processing circuits for logically terminating a data link via each dedicated line, and 703 is a destination of data input from any dedicated line. Is an arithmetic processing circuit that reads the data and transfers the data to a predetermined dedicated line to which the other device is connected.

The communication path signal and the call control signal between the call connection processing devices 503a to 503c and the radio base stations 505a to 505e are carried by a normal signaling system supported by the public network 504. A dedicated line network is formed between each of the call connection processing devices 503a to 503c and the database device 501, and a call control signal, a location registration signal of a mobile station, an inquiry / response signal of mobile station management information, and the like are transmitted at a high speed. It has become something. Note that a plurality of radio base stations to be controlled are preset in each of the call connection processors 503a to 503c.

Next, the operation from the time when the mobile station 105 makes a call to the radio base station 101 will be described with reference to FIGS. FIG. 6 is a sequence diagram showing a mobile station calling sequence between the mobile station, the radio base station, and the call connection processing device. First, the radio base station 101 always uses the BCCH as a broadcast / line allocation status notification signal m11d1 to provide its own identification number and line allocation status information indicating whether or not the TCH of the local station has room for one or more channels. Broadcasting. The mobile station 105 extracts necessary information from the BCCH of the radio base station 101, calls the radio base station 101 with a link channel establishment request signal m12u in response to a call operation from a user of the mobile station 105, and The radio base station 101 that has accepted the call from the station 105 notifies the mobile station 105 of the radio channel information necessary for the mobile station 105 to perform the call processing by using the link channel assignment signal m12d.

Mobile station 105 that has obtained wireless channel information
Are synchronized with the radio base station 101 and the synchronous burst signals m13u and m1 for the time slot of the designated radio frequency signal.
3d is transmitted and received to establish synchronization, and the SABM signals m14u and m14d are transmitted and received to establish the FACCH and SACCH layers 2 of the control channel with the radio base station 101.
The mobile station 105 that has established Layer 2 transmits a call setting signal m15u on the FACCH or SACCH to the radio base station 101.
Send to

Upon receiving the call setting information from the mobile station 105, the radio base station 101 connects the data line 1 to the public network 104.
01d, it connects to the data line 103c of the call connection processing device 103 which is set in advance as a high-order jurisdiction station, and then communicates call control information on the mobile station 105 with the call connection processing device 103 in call processing. After establishing a data link for communication, the mobile station 105 notifies the mobile station 105 of the call setting information and the fact that a call is to be made using the communication line 101a as a communication path on the public network 104 to the mobile station 105 as a mobile station call information signal f11u. I do. In FIG. 1, a data link on the public network 104 is indicated by a broken line.

The call connection processing device 103 recognizes from the mobile station call information that the call is to be made using the communication line 101a as a communication path with the connection request destination of the mobile station 105, and to the public network 104 for the mobile station 105. The mobile base station 101 is notified by the mobile station call information reception signal f11d so that the call is received at the communication line 103a as the upper communication path. After transmitting the call setting acceptance signal m15d to the mobile station 105, the radio base station 101 outputs a signal m for radio channel management and mobility management.
From 16u to m21u, the mobile station 105 transmits and receives.

After receiving the mobile station call information acceptance signal f11d from the call connection processing device 103, the radio base station 101 performs a call connection process for allocating a communication path to the mobile station 105 on the public network 104. Talk line 1 of device 103
A call setting signal f11u is transmitted from the communication line 101a using the signal system of the public network 104 with the destination 03a as the destination. The call connection processing device 103 includes a communication line 101a of the radio base station 101 and a communication line 103 of the call connection processing device 103.
is connected to the mobile station 10 via the public network 104.
5 is returned to the radio base station 101, indicating that the call setting acceptance signal f12d indicates that it is assigned as a communication path on the public network 104 for the communication network No. 5.

On the other hand, when the call connection processing device 103 extracts from the mobile station call information from the mobile station 105 received via the radio base station 101 that the communication partner is the subscriber 106 of the public network 104, A call is sent as a general subscriber to the public network 104 via the communication line 103e with the caller 106 as a destination, and the call connection processing device 1 is transmitted via the public network 104.
A call path for connecting the subscriber 03 and the subscriber 106 is secured, and a response from the subscriber 106 is waited. Further, when the call connection processing device 103 transmits the call to the subscriber 106, the call connection processing device 103 notifies the wireless base station 101 that the subscriber 106 is being called based on the signal system on the public network 104 via the communication lines 103a and 101a. After transmitting the ringing signal f13d, a ringback tone signal f14d is transmitted via the communication lines 103a and 101a.

The radio base station 101 converts the call signal f13d into m22d for the mobile station 105, notifies the mobile station 105 of the converted signal on the SACCH, and outputs a ringback tone signal f from the public network 104.
14d is transmitted on the TCH as m23d. Mobile station 1
In step 05, the TCH is enabled when the call signal m22d is received, and the ringback tone signal m23d subsequently sent from the radio base station 101 is heard as a sound by the user's ear.

Thereafter, when the call connection processing device 103 detects a response from the subscriber 106, the call connection processing device 103
The transmission of the ringback tone signal f14d flowing to the communication line 01a is stopped, and the response of the subscriber 106 is notified to the wireless base station 101 by a response signal f15d according to the signal system of the public network 104 on the communication lines 103a and 101a. In the call connection processing device 103, both communication paths of the communication lines 103e and 103a are connected. The wireless base station 101 relays the response of the subscriber 106 from the call connection processing device 103 to the mobile station 105 as a response signal m24d, whereby the mobile station 105 shifts to a communicating state using TCH, Communication between users is substantially started, and a line connection as shown in FIG. 1 is formed.

Next, a radio base station switching process when the mobile station 105 moves to receive a communication service from the radio base station 102 will be described with reference to FIG. 2 and FIGS. FIG. 2 is a configuration diagram showing a line connection state when the mobile station 105 shown in FIG. 1 moves and receives a communication service from the radio base station 102, and FIGS.
FIG. 5 is a sequence diagram showing a switching sequence of a wireless base station. The following description focuses on the fact that a digitized signal is transmitted in a time division manner in a wireless section between a mobile station and a wireless base station.

The mobile station 105 in communication shown in FIG. 1 uses the idle time during which no burst signal is transmitted / received to / from the wireless base station 101 and broadcasts by the wireless base station located near the own station. The radio channel BCCH is intercepted, and the reception level and the line assignment state information are constantly monitored from the broadcast / line assignment state notification signal m30d1. here,
When the deterioration of the reception state with the radio base station 101 is detected,
The mobile station 105 first assigns the wireless base station 102 that transmits the line allocation status information indicating the optimum reception level and the presence of the idle wireless channel to the wireless base station 102, and assigns the priority to the other wireless base stations. Switching to radio base station 101 by TCH
It is requested by the switching request signal m31u. Wireless base station 101
Transmits a switching request from the mobile station 105 to the call connection processing device 103 as a wireless base station switching request signal f31u via a data link on the data lines 101d and 103c.

The call connection processing device 103 sends a switching request acceptance signal f31d as a response to this request,
01, the data line 1 via the public network 104
The mobile station 105 sends a wireless channel reservation request signal f32d to the wireless base station 102 by establishing a data link between the mobile station 105 and the mobile station 105.
And a request for securing a wireless channel to be allocated to the mobile station 105. The radio base station 102 determines that the allocation has been completed when the line allocation status information can be updated by subtracting one channel so that the mobile station 105 can allocate a radio channel, and sets a predetermined timer to secure the radio channel. The answer signal f32u is returned to the call connection processing device 103, and the updated line assignment state information is sent to the BCCH
Notify by the above signal m30d2

The line assignment state information is transmitted to the mobile station 1
When the TCH 05 no longer uses the TCH of the wireless base station 102, the TCH1 channel is updated to an empty state again. The timer set by the wireless base station 102 automatically sets the secured wireless channel when the mobile station 105 fails to switch the wireless base station and times out even if the wireless channel for the mobile station 105 is secured. It has a role to release it. Further, when the reservation of the wireless channel is rejected by the wireless base station 102, the call connection processing apparatus 103 issues a wireless channel securing request to the second desired switching destination wireless base station notified by the mobile station 105. Will do.

The call connection processing device 103 is connected to the radio base station 10
When the base station 101 receives the response from the wireless base station 101
Sends a switching instruction signal f33d via the data link to instruct the mobile station 105 to select the wireless base station 102 as the switching destination wireless base station. The wireless base station 101
The switching instruction from the call connection processing device 103 is relayed to the mobile station 105 by the TCH switching instruction signal m31d. on the other hand,
The mobile station 105 that has received the switching instruction is the switching destination radio base station 1
02 is substantially the same as the calling procedure described with reference to FIG. 6 except for the process of calling the wireless base station 102 ignoring the line allocation status information transmitted by the communication device 02 and the process of calling the communication partner. The sequence from m33u to m41d of 7, 8 is advanced.

The radio base station 101 is connected to the mobile station 105
After the mobile station 105 switches to the wireless base station 102 and the wireless channel is disconnected, the mobile station 105 synchronizes with the disconnected wireless channel so that the mobile station 105 can continue the call immediately after returning to the failed wireless base station. The burst signal m32d is continuously transmitted, and an idle signal is transmitted to the public network 104 so that an abnormal sound is not heard by the connected public network subscriber 106. On the other hand, when receiving the call setting signal m36u following the call from the mobile station 105, the wireless base station 102 connects the data lines 102d and 103d via the public network 104 and establishes a data link thereon. A call setting request from the mobile station 105 is notified to the call connection processing device 103 as a mobile station call information signal f34u, and at the same time, a line to be allocated for the communication path of the mobile station 105 on the public network 104 is originated from 102a. Notify that.

The call connection processor 103 knows from the mobile station call information signal f34u that the mobile station 105 has switched the radio base station, and returns the mobile station call information acceptance signal f34d to the radio base station 102. Mobile station 105 on the public network
Communication line 10 as a line to be allocated for the communication path for
Notify 3b to receive the call. The radio base station 102
When the mobile station call information reception signal f34d is received, the communication line 10 between the call connection processor 103 and the wireless base station 102 is received.
In order to connect 2a and 103b on the public network 104, the call processing sequence with the call connection processor 103 is changed from f35u to f3.
At the time point when the processing is advanced to 7u, the hold signal f38u is transmitted from the wireless base station 102 side to the call connection processing apparatus 103 via the data link. Further, the call connection processing device 10 receiving this signal
Reference numeral 3 holds the corresponding line, and returns the hold acceptance signal f38u to the wireless base station 102 via the data link.

On the other hand, the radio base station 102 is proceeding with the call processing sequence on the radio line for the mobile station 105 as described above in parallel with the connection processing on the public network, and is ready for the radio line. 8, that is, when the UA signal m40u is received from the mobile station 105 in FIG. 8, the hold release signal f39u is released from the data to release the hold of the communication channel line of the mobile station 105 held on the public network 104. The call is sent to the call connection processing device 103 via a link. Call connection processing device 1
03, upon receiving the signal f39u, returns a hold release acceptance signal f39d to the wireless base station 102 via a data link, and simultaneously calls the line 103e and the line 103b connected to the subscriber 106 via the public network 104. The connection is made in the connection processing device 103. At this point, the assignment of the communication line to the mobile station 105 is completed, the wireless base station 102 sends a response signal m41d to the mobile station 105, and the communication between the mobile station 105 and the subscriber 106 is resumed, and the mobile station 105 is communicating.

The call connection processing device 103 is connected to the line 10
3a, the source wireless base station 101 via the public network 104
Between the mobile station 105 and the base station in case the mobile station 105 fails to switch the radio base station.
40d to the wireless base station 101. In response, the wireless base station 101 disconnects the line reserved for the mobile station 105 and sends a disconnection completion signal f40u to the call connection processing device 1.
03 is returned, and if there is no other data to be communicated by call processing or the like, the data line is released, and the wireless base station switching processing for the mobile station 105 is completed.

[0053]

As described above, according to the present invention, the call connection processing means for controlling the call connection to the radio base station and the mobile station are respectively connected to the public network as subscribers, and the call connection request from the mobile station is provided. A call from the wireless base station to any call connection processing means via the public network, establishes a communication line with the communication partner via the public network by the call connection processing means, and The switching request is transferred from the wireless base station to the corresponding call connection processing means via the public network in response to the wireless base station switching request, and the call connection switching means transfers the new wireless base station and mobile station via the public network. Switching connection to the communication line with the wireless base station, it is possible to arbitrarily connect the wireless base station and its higher station, that is, the call connection processing means, via the existing public network, and to request switching of the wireless base station. Occurs, As described above, a call connection processing unit switches a call connection to an arbitrary wireless base station via a public network without requiring equipment for realizing a call transfer process requiring a large amount of information and a complicated connection process. The wireless base station can be switched only by itself, and the economic burden required for system construction can be reduced.

When the mobile station communicating with the first radio base station detects a deterioration in the radio wave reception state, the mobile station is prioritized and selected according to the radio wave reception level and the line allocation state information. A mobile base station transmits a switching request for a wireless base station with a plurality of wireless base stations as switching candidates, and in response to an incoming call from the wireless base station via the public network based on the switching request, the call connection processing means is given priority. Requesting each wireless base station to secure a wireless channel and establish a wireless channel with the mobile station based on the established wireless channel, and perform call connection switching processing in accordance with the wireless channel establishment. As in a mobile communication system in which the connection device is connected to a public network, there is no need to have a communication partner specify a transfer destination wireless base station or manage a wireless channel information in a database to perform call transfer processing. In addition Like the mobile communication system using the call waiting service of the telephone exchange of, without requiring an operation for the radio base station switching to the mobile station and the communication partner, based on the radio wave reception state at the mobile station,
The switching process to the optimum wireless base station is automatically performed, and the user and the communication partner can continue the communication without being aware of the switching of the wireless base station.

Further, in the second radio base station selected as the switching destination, in response to the channel reservation request from the call connection processing means, after establishing a free channel before establishing a radio channel with the mobile station, In response to a call from the mobile station within a predetermined time after updating of the line assignment state information and ignoring the line assignment state information of the second wireless base station, a wireless channel with the mobile station is established with the reserved wireless channel. Therefore, it is possible to completely avoid the problem that the switching fails due to the full radio channel of the switching destination radio base station in which the standard (RCR STD-28) of the conventional second generation cordless telephone system is inherent. Thus, it is possible to realize a safe and reliable switching process of the wireless base station.

In addition to being connected to a predetermined dedicated line network, database means for managing location registration information and subscriber information on all mobile stations as mobile station management information are provided, and all call connection processing means are dedicated. It is connected to a line network, accesses database means via this dedicated line network, and exchanges various call control information with other call connection processing means. It is possible to provide digital mobile communication services even in a larger area, and when access to database means is not necessary, call connection processing means can be used between call connection processing means. Can exchange information directly, reduce unnecessary access to database means,
This reduces the processing load on the database means.

[Brief description of the drawings]

FIG. 1 is a configuration diagram (before switching) of a digital mobile communication system according to an embodiment of the present invention.

FIG. 2 is a configuration diagram (after switching) of the digital mobile communication system according to one embodiment of the present invention.

FIG. 3 is a block diagram of a call connection processing device.

FIG. 4 is a block diagram of a wireless base station.

FIG. 5 is a block diagram of a mobile station.

FIG. 6 is a sequence diagram showing a mobile station calling sequence.

FIG. 7 is a sequence diagram (first half) showing a switching sequence of a wireless base station.

FIG. 8 is a sequence diagram (second half) illustrating a switching sequence of the wireless base station.

FIG. 9 is a configuration diagram relating to a call control information transmission system in the mobile communication system of the present invention.

FIG. 10 is a block diagram of a database device.

FIG. 11 is a block diagram of a data exchange device.

FIG. 12 is a configuration diagram showing a conventional mobile communication system.

FIG. 13 is a configuration diagram showing another conventional mobile communication system.

FIG. 14 is a sequence diagram showing a conventional mobile station calling sequence.

FIG. 15 is a sequence diagram showing a conventional radio base station switching sequence.

[Explanation of symbols]

101, 102: wireless base station, 103: call connection processing device, 104: public network, 105: mobile station, 106: subscriber terminal, 103a, 103b, 103e: communication line, 10
3c, 103d: data line, 501: database device, 502: data exchange device.

Claims (4)

(57) [Claims] 1. A digital mobile communication system for providing various services by transmitting a digitized signal in a time-division manner over a wireless line between a mobile station and a wireless base station, and connecting as a subscriber to a public network. And a call connection processing means connected to the public network as a subscriber and controlling a call connection to the mobile station , wherein the radio base station responds to a call connection request from the mobile station. The public
Make a call to a predetermined call connection processing means via a public network and communicate
Radio base station in response to a radio base station switching request from a moving mobile station.
From the station to the corresponding call connection processing means via the public network.
The call connection processing means transfers the switching request in response to the outgoing call from the radio base station.
Make a call to the connection partner via the public network and communicate with the communication partner
Incoming call from the radio base station according to the communication line establishment
Establishes communication by connecting to a call to the communication partner, and
Via the public network in response to the switching request from the wireless base station
To establish a communication line between the new radio base station and the mobile station
After that, disconnect the communication line with the communication partner to this communication line.
A digital mobile communication system characterized in that the mobile communication system is reconnected . 2. The digital mobile communication system according to claim 1, wherein each of the radio base stations includes identification information for identifying the self station and information in the self base station as system information that is constantly broadcast to the mobile station through a predetermined radio channel. Transmitting line allocation status information indicating whether or not a wireless channel that can be newly connected for call connection is held, and when the mobile station detects deterioration of the radio wave reception status during communication with the first radio base station. A plurality of radio base stations according to the reception level of the radio wave broadcast from another radio base station received using the idle time of the time-division communication and the identification information and the line assignment state information in the received system information. Stations are prioritized and selected, and each of the selected wireless base stations is transmitted as a switching candidate to the first wireless base station to transmit a wireless base station switching request, wherein the first wireless base station And said A switching request is issued via the public network to the call connection processing unit to which the mobile station is connected, and the call connection processing unit sets the priority in accordance with the incoming call based on the switching request. To each of the wireless base stations, based on the request to transmit a wireless channel reservation via the public network, when the second wireless base station among the respective wireless base stations returned channel secure completion, The mobile station communicates with the communication partner of the mobile station in accordance with the establishment of a wireless channel between the mobile station and the second wireless base station using the reserved wireless channel.
When the wireless link between the mobile station and the second wireless base station was not established, or the channel securing completion was not returned from any of the wireless base stations. In such a case, communication between the mobile station and the first wireless base station is restored. 3. The digital mobile communication system according to claim 2, wherein the second wireless base station secures a free wireless channel in response to a channel securing request from the call connection processing means and returns a channel secure completion. And updates the line assignment status information in the system information, and establishes a wireless channel with the mobile station by a wireless channel secured in response to a call from the mobile station within a predetermined time from the update of the line assignment status information. Establishing, the mobile station, according to the switching destination radio base station information to the second radio base station transmitted from the call connection processing means via the first radio base station as a switching destination, A digital mobile communication system, wherein a call is transmitted to said second radio base station ignoring line assignment status information from the second radio base station. 4. A digital mobile communication system according to claim 1, further comprising a database means connected to a predetermined dedicated line network and managing location registration information and subscriber information on all mobile stations as mobile station management information. Provided, all the call connection processing means are connected to a predetermined dedicated line network, acquire necessary mobile station management information from the database means, and update the mobile station management information in the database means, A digital mobile communication system characterized by exchanging various kinds of call control information with another call connection processing means via the dedicated line network.