JP2000287248A - Radio base station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio base station which reduces a traffic amount in a telephone network by deciding whether or not an caller side mobile station and a callee side mobile station corresponding to the other station exist in the area of present station and mutually connecting radio lines of mobile stations when they are decided to exist. SOLUTION: In an ADPCM processing part 40, when it is decided by a CPU 70 that a calling side mobile station and an incoming call side mobile station corresponding to it exist in an area of its own station (a radio base station 100), a radio line of the caller side mobile station and a radio line of the callee side mobile station are mutually connected. That is, the CPU 70 mutually connects both the radio lines in the ADPCM processing part 40 and disconnects connection with a telephone network when the caller side mobile station and the callee side mobile station exist in the area of the radio base station 100. As a result, since the caller side mobile station and the callee side mobile station can communicate with each other through no telephone network, it is possible to reduce a traffic amount in the telephone network.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio base station for switching a connection path.

[0002]

2. Description of the Related Art In a mobile communication system, a plurality of radio base stations installed in various places are connected to a telephone network such as an ISDN, and mobile stations are relayed by relaying a radio line with the mobile station and the telephone network. It enables communication between stations. FIG.
0 is a diagram showing a schematic configuration of a mobile communication system.

In FIG. 1, a mobile communication system is an IS
It is composed of exchanges 1 and 2 which are components of a telephone network such as a DN, a control station 3 which performs location management of mobile stations, etc., radio base stations 4 and 5 which relay a radio line and a telephone network, and mobile stations 6 and 7. Is done. When the mobile station 7 attempts to communicate with the mobile station 6 1)
The mobile station 7 transmits a call setting signal to the radio base station 5. 2)
The wireless base station 5 returns a call setting confirmation signal to the mobile station 7 and transfers the call setting signal to the exchange 2. 3) Switch 2
Queries the control station 3 of the mobile communication system about the position of the mobile station 6, and as a result, obtains the position information of the mobile station 6. Here, the location information is indicated by the identification number (CS-ID) of the radio base station 4 whose location is registered in the control station 3 by the mobile station 6 via the radio base station 4 and the exchange 1. 4) The exchange 2 transfers the call setup signal to the exchange 1 to which the wireless base station 4 is connected based on the location information. 5) Exchange 1
The call setting signal is transferred to the radio base station 4. 6) The radio base station 4 transfers the call setting signal to the mobile station 4. According to such a procedure, a call setting signal is transmitted from the mobile station 7 to the mobile station 6 to establish a call, and when the mobile station 6 responds, the mobile station 7
-Wireless base station 5-exchange 2-exchange 1-wireless base station 4-
The communication path of the mobile station 6 is set, and the mobile station 7 and the mobile station 6 are set.
Starts communication.

[0004]

In the above-mentioned prior art mobile communication system, when two mobile stations communicate with each other under the control of the same radio base station, for example, as shown in FIG. When the station 6 'and the station 6' are present in the area of the radio base station 5 and communicate with each other, the communication route is as follows: mobile station 7-radio base station 5-switch 2-radio base station 5
Mobile station 6 '. In this communication path, a communication path reciprocating between the wireless base station 5 and the exchange 2 is useless. There is a problem that the exchange 2 is uselessly occupied by the traffic due to the useless communication path.

[0005] In view of the above problems, an object of the present invention is to provide a radio base station which reduces the amount of traffic in a telephone network by solving the problem that traffic is wastefully occupied in an exchange.

[0006]

In order to solve the above-mentioned problems, a radio base station according to the present invention has a radio interface for connecting mobile stations by radio and a telephone network interface. Determining means for determining whether a calling mobile station and a corresponding called mobile station are present in the area of the mobile station, and Connecting means for mutually connecting the wireless lines of the two mobile stations via a wireless interface when it is determined that the mobile stations exist.

[0007] Further, the determination means includes, for each mobile station wirelessly connected, a call management table storing a record in which the number of the calling mobile station and the number of the called mobile station are associated with each other, and Updating means for updating the call management table based on the call control information notified from the mobile station or the telephone network, wherein the numbers of the calling mobile stations match between the records of the call management table, and The determination is made by detecting two records having the same mobile station number.

The call control information includes a call request from a mobile station in the area, a call request to a mobile station in the area,
Alternatively, the request is a recall request from a mobile station that has moved into the area for handover. Further, the determining means is configured to make a determination when the call management table is updated by the updating means.

The radio base station has a radio interface for connecting the mobile station by radio and a telephone network interface,
A wireless base station for connecting a wirelessly connected mobile station to a telephone network, wherein the determining means determines whether two wirelessly connected mobile stations are communicating with each other, and is communicating with each other. Connection means for connecting the radio lines of the two mobile stations to each other via a radio interface and disconnecting from the telephone network.

The wireless base station has a wireless interface for connecting the mobile station wirelessly and a telephone network interface, and is a wireless base station for connecting a wirelessly connected mobile station to a public network. When receiving a call request, determining means for determining whether the called mobile station specified in the call request is within the wireless area of the wireless base station, and determining that the mobile station is present Connecting means for mutually connecting the wireless line of the calling mobile station and the wireless line of the called mobile station via a wireless interface.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <First Embodiment> A radio base station according to a first embodiment will be described below with reference to the drawings. The radio base station according to the present embodiment is configured such that, when two mobile stations (for example, the mobile station 8 and the mobile station 9) exist under the radio base station and communicate with each other, the mobile station 8 and the radio base station The communication is switched from the communication via the communication route of the switching system, the present wireless base station and the mobile station 9 to the communication route of the mobile station 8-the present wireless base station and the mobile station 9.

FIG. 1 is a block diagram showing a configuration of a radio base station according to the present embodiment. In the figure, the radio base station includes an antenna 10, a radio unit 20, a TDMA / TDD (Tim
e Division Multiple Access / Time Division Duplex) processing unit 30, ADPCM (adapted PCM for bandwidth com)
pression) processing unit 40, telephone network interface 50
(Hereinafter abbreviated as telephone network I / F 50), call management table 6
0, CPU 70.

The radio unit 20 includes a transmission / reception amplifier (not shown), a modulation / demodulation unit (not shown), and the like.
The transmission / reception of the π / 4 QPSK modulation signal by the TDD method is performed. Here, the 4-channel TDMA / TDD method is 5 m
In this scheme, a frame for each s is divided into eight slots, that is, four slots for uplink (mobile station → radio base station) and four slots for downlink (radio base station → mobile station), and a control channel and a communication channel are assigned to each slot. In the present embodiment, this method is used to allocate a control channel to one set of uplink and downlink slots, and allocate communication channels to the remaining three sets of uplink and downlink slots. This allows up to three mobile stations to communicate simultaneously via the radio base station 100.

The TDMA / TDD processing unit 30 allocates communication channels to three uplink and three downlink slots and decomposes and assembles frames of control channel and communication channel signals. The TDMA / TDD processing unit 30 has a function of arbitrarily assigning a communication channel to a plurality of decoders and encoders of the ADPCM processing unit 40 described later, and a function of assigning a communication channel to an arbitrary B channel of the telephone network I / F 50. Having. The decoder and the encoder will be described later.

The ADPCM processing section 40 has a TDMA / TD
Between the D processing unit 30 and the telephone network I / F 50, a 32 kbit / s ADPCM signal (hereinafter abbreviated as a 32k signal) used in a radio line and a telephone network are used for each communication channel and for each uplink and downlink slot. 64kbit / sμlaw PCM signal (hereinafter 64
k signal). Here, the wireless line indicates a communication path between the wireless base station 100 and a mobile station under the wireless base station 100. The telephone network refers to a digital network such as an ISDN to which an exchange, a control station, and the like are connected as shown in FIG.

The ADPCM processing section 40 outputs the 32k signal and 6
By converting the 4k signal, a wireless line in each communication channel is connected to a telephone network. Here, this connection is called a normal connection. Conversion of a 32k signal to a 64k signal is called decoding, and conversion of a 64k signal to a 32k signal is called encoding. Further, as a function unique to the present invention, the ADPCM processing unit 40 includes a CPU.
If it is determined by 70 that the calling mobile station and the corresponding called mobile station are present within the area of the own station (wireless base station 100), the wireless line of the calling mobile station and the called mobile station It has the function of interconnecting the mobile station's wireless line. Here, connecting the wireless line of the calling mobile station and the wireless line of the called mobile station to each other is called loopback connection.

The telephone network interface unit 50 has a DSU
(Not shown) and a telephone line control unit (not shown).
The DSU has four B-channel and one D-channel interface. The four B channels are TDMA
It is used for an arbitrary communication channel according to the assignment by the / TDD processing unit 30, and the D channel is used for the control channel.

The call management table 60 stores call information for each wirelessly connected mobile station within its own area, that is, for each call within its own area. Here, the term “call” refers to a series of exchanges of signals for communication at a mobile station under the control of the radio base station 100. Calls exist for the number of mobile stations wirelessly connected to the wireless base station 100. Also, here, the call information includes the number of the mobile station for indicating the correspondence between the calling mobile station and the called mobile station in the call, a flag indicating whether a loopback connection is possible, a call for the call, and the like. It consists of a call setup message received by the wireless base station 100 at the time of the setup request. The call information stored in the call management table 60 is created by the CPU 70 and written into the call management table 60, and is read from the call management table 60 by the CPU 70. Call information is transmitted when a mobile station within its own area transmits a call setup signal.
When a mobile station in another area has transmitted a call setup signal to the own station via the telephone network, and the mobile station transmits a call setup signal (handover) to the radio base station 100 to perform handover into the area of the own station. When the wireless base station 100
Is created based on the call setup message received from the mobile station.

The CPU 70 performs call control for transmitting and receiving call control information. Here, the call control information includes a call setting request,
Refers to a series of control signals exchanged between mobile stations when two mobile stations communicate with each other, such as calling, answering, and releasing. Since these pieces of call control information conform to the “2nd generation cordless telephone system standard RCR STD-28”, detailed description is omitted.

The CPU 70 transmits call control information such as disconnection and call setting to the telephone network in accordance with switching between the loopback connection and the normal connection. The CPU 70 updates the call management table 60 based on the transmitted and received call control information. Here, the update is addition, deletion, or update of information in the call management table 60.

The CPU 70 further includes a call management table 60
The call information of any two mobile stations stored therein is compared to determine whether they can make a loopback connection. C
When it is determined that the connection is possible, the PU 70 instructs the ADPCM processing unit 40 to perform the loopback connection. <Detailed Description of ADPCM Processing Unit 40> FIG.
FIG. 3 is a block diagram showing a detailed configuration of an M processing unit 40.

In the figure, an ADPCM processing unit 40 includes selectors 415 to 418 for performing a loopback connection, decoders 421 to 424 for decoding, encoders 425 to 428 for encoding, and decoder input terminals (decoders 421 to 424) corresponding to the decoders 421 to 424. (Hereinafter abbreviated as DI terminal) 4
01 to 404, decoder output terminals (hereinafter abbreviated as DO terminals) 431 to 434, and encode input terminals (hereinafter abbreviated as EI terminals) 4 corresponding to the encoders 525 to 428.
35 to 438 and encode output terminals (hereinafter abbreviated as EO terminals) 405 to 408.

At the time of normal connection, the decoders 421 to 424 decode a 32k signal input from the DI terminals 401 to 404 into a 64k signal and output the same to the DO terminals 431 to 434. 32k input to the decoders 421 to 424
Each signal corresponds to a signal transmitted from a mobile station in an uplink slot to which a communication channel is assigned.

The decoders 421 to 424 stop decoding at the time of loop connection. Encoders 425-4
The selector 28 converts the 64k signal input from the EI terminals 435 to 438 into 32k and converts the signal to 32k during normal connection.
To EO terminals 405 to 408 via.
Each of the 32k signals output from the encoders 425 to 428 corresponds to a signal transmitted to a mobile station in a downlink slot to which a communication channel is assigned.

The selectors 415 to 418 output the 64k signals output from the encoders 425 to 428 to the EO terminals 405 to 408 during normal connection, and the DI terminals 401 to 404 from the DI terminals 401 to 404 during return connection.
32k signal input through the EO terminals 405-4
08. In the normal connection, the decoder 421
424 and encoders 425 to 428 are paired, and each pair, that is, “decoder 4
21, encoder 425 "," decoder 422, encoder 426 "," decoder 423, encoder 42 "
7 ”and“ decoder 424, encoder 428 ”are assigned communication channels. For example, in two sets of uplink and downlink slots, when two mobile stations in the area independently communicate with the other mobile station outside the area (in this case, since the communication channels are allocated to the two mobile stations, respectively, Although there are two channels, in this case), the ADPCM processing unit 40 supplies each of two of the four pairs (for example, the “decoder 421 and the encoder 425” and the “decoder 422 and the encoder 426”) respectively. Assign a communication channel.

As described above, the ADPCM processing unit 40
Up to three communication channels can be processed simultaneously. On the other hand, when the loopback connection is performed, the communication channel allocation in the ADPCM processing unit 40 is as follows. Here, the calling mobile station and the called mobile station exist in the area, and the respective communication channels are called a calling communication channel and a called communication channel.

In this case, when the 32k signal of the uplink slot of the calling communication channel is input from the DI terminal 401,
The signal is output from the EO terminal 405 via the selector 415 by the loopback connection, and the output 32k signal is used as the signal of the downlink slot of the called communication channel by the TDMA.
It is processed by the / TDD processing unit 30 and transmitted to the called mobile station.

Similarly, when the 32k signal of the uplink slot of the called communication channel is input from the DI terminal 402,
The signal is output from the EO terminal 406 via the selector 416 by the loopback connection, and the output 32k signal is used as the signal of the downlink slot of the calling communication channel by the TDMA.
It is processed by the / TDD processing unit 30 and transmitted to the calling mobile station.

In this way, in the case of the loopback connection, the 32k signal in the uplink slot of one communication channel for one mobile station is returned and output when the loopback connection is performed in the downlink slot of the communication channel for the mobile station of the communication partner. Processed as a 32k signal. This is the same for the mobile station of the communication partner. In the case of the folded connection in this way, the signals output from the two EO terminals are:
In the TDMA / TDD processing unit 30, each signal is processed as a signal of the other party's downlink slot.

The decoders 421 to 424 and the encoders 425 to 428 may be constituted by one processor instead of them. <Detailed Description of Call Management Table 60> FIG. In the figure, rows 301,
Reference numerals 302 and 303 denote call information, respectively. Each call information corresponds to a call on a wireless line in the area of the wireless base station 100. The call information includes various items shown in columns 304 to 310.

The call management number 304 indicates a number for identifying a call on a radio line in the area of the radio base station 100. Indicates a call management number for identifying each piece of call information. The calling number 305 indicates a number for identifying the mobile station (calling mobile station) that originated the call according to each piece of call information. Here, the calling number is a number assigned in advance to the mobile station, such as the telephone number or PS-ID of the mobile station.

The called number 306 indicates a number for identifying a destination mobile station (called mobile station) for a call originator related to each piece of call information. Here, the called number is a number assigned to the mobile station in advance, such as the telephone number or PS-ID of the mobile station. The shortcut flag 307 indicates a flag for identifying whether or not a return connection is possible with respect to a wireless channel of a mobile station in an area for a call. When the shortcut flag is on, it indicates that the call can be connected back, and when it is off, it indicates that the call cannot be connected.

The outgoing call flag 308 is a flag for identifying whether or not a mobile station in an area for a call is a calling mobile station (is a called mobile station). The calling flag is
When on, it indicates that the mobile station involved in the call is the calling mobile station, and when off, it indicates that it is the called mobile station. The communication destination call management number 309 indicates a call management number corresponding to the mobile station of the other party when making a return connection. Invalid if loopback connection is not performed.

The data 310 includes other items (304 to 30).
9 shows a call setup message from which 9) was created. Among these items, the call management number 304, the calling number 305, the called number 306, the calling flag 308, and the data 310 are created by the CPU 70 when the own station receives the call setting request, and written into the call management table 60. It is.

The shortcut flag 307 is created and written when a call setting request is made, and each time the call information is updated, the shortcut flag in each call information is considered, and is changed when there is a change. The communication destination call management number 309 is written by the CPU 70 when making a return connection or releasing the return connection. <Connection Sequence> FIG. 4 shows a connection sequence when the mobile station 8 and the mobile station 9 existing in the area of the radio base station 100 communicate with each other. In FIG.
Is the calling mobile station, and the mobile station 9 is the called mobile station.

In the radio base station 100, the CPU 70
When a call setting request is received from the mobile station 8, call information is created based on the call setting message included in the call setting request and added to the call management table 60 (S401, S40).
2). The CPU 70 transmits a call setting reception indicating that the call setting request has been received to the mobile station 8, and transfers the call setting request to the exchange on the telephone network side (S403, S404).

The CPU 70 receives a call setting acceptance from the exchange on the telephone network side (S405). The exchange on the telephone network side
Based on the called number in the transferred call setup message, the control station inquires of the control station about the location information of the mobile station 9 having the called number. As a result, the mobile station 9 replies that the mobile station 9 exists in the area of the radio base station 100. Is received from the control station. The exchange is a CPU 70
(S406).

The CPU 70 creates call information based on the call setting message transferred from the exchange, and adds it to the call management table 60 (S407). The CPU 70 transmits a call request to the mobile station 9 and, as a result, the call response is transmitted to the mobile station 9.
When a reply is received, the call setting reception is transferred to the exchange (step 410). The CPU 70 searches the call management table and determines whether a call back connection is possible for each call of the call information (step 411). This determination is made by comparing the calling number and the called number of one call information with the calling number and the called number of the other call information. As a result, if the calling number and the called number are the same, the call It is determined that the call for information can be connected back.

Here, it is determined that the call information of the mobile station 8 and the call information of the mobile station 9 can be looped back, and the respective shortcut flags are set to ON. CPU
70 transmits a call setting request to the mobile station 9, and as a result, a call setting acceptance is replied (S412, 413). Mobile station 9
Receives a call setting, sounds a ringtone to notify the user, and transmits a call signal indicating that the call is being made to the wireless base station 100 (step 414).

When the CPU 70 transfers the call signal to the exchange, the call signal is transferred from the exchange to the mobile station 8, so the CPU 70 transfers the call signal to the mobile station 8 (S415, S416). , S417). When the user responds, a response signal and a response acknowledgment are exchanged on the route of the mobile station 9 → the radio base station 100 → the exchange → the radio base station 100 → the mobile station 8 (S418 to S4).
25), the mobile station 8 and the mobile station 9 shift to communication via the previous route (S426).

When the communication between the mobile station 8 and the mobile station 9 is established, the CPU 70 refers to the shortcut flag in the call management table 60 to detect a call that can be returned and establishes two calls that can be returned. The call is looped back (S428). Here, since the calls of the mobile station 8 and the mobile station 9 can be looped back, A
The mobile station 8 and the wireless line of the mobile station 9 are connected to the DPCM processing unit 40. Next, the CPU 70 performs a disconnection process with the exchange, and disconnects the route between the radio base station 100 and the exchange in the route of the mobile station 8-the radio base station 100-the exchange (S).
430-S432).

As a result of the previous disconnection, the exchange receives the
Since a disconnection signal for disconnecting between the exchange and the radio base station 100 on the route between the radio base station 100 and the mobile station 9 is transmitted, the radio base station 100 establishes a connection between the exchange and the radio base station 100. Disconnect the route (S433-44)
5). As a result, the mobile station 8 and the mobile station 9 are
Communication is performed via the route between the wireless base station 100 and the mobile station 9 (S436).

As described above, the CPU 70 controls the mobile station 8
If the mobile station 9 and the mobile station 9 are within the area of the wireless base station 100, the two wireless lines are connected to each other in the ADPCM processing unit 40, and the connection to the telephone network is disconnected. As a result, the mobile station 8 and the mobile station 9 can communicate with each other on the route of the mobile station 8, the wireless base station 100, and the mobile station 9 without passing through the telephone network. can do. <Disconnection Sequence> FIG. 5 shows that the mobile station 8 and the mobile station 9 existing in the area of the wireless base station 100 and communicating with each other by the loopback connection end communication, and the mobile station 8 becomes the wireless base station. A disconnection sequence when a disconnection signal is transmitted to 100 is shown.

When receiving the disconnection signal from the mobile station 8, the CPU 70 refers to the call information in the call management table 60 and determines whether or not the call is connected back (S50).
2, S503). More specifically, the CPU 70 first refers to the item of the destination call control number in the call information corresponding to the call control number in the disconnection message. By this reference, the CPU 70
Determines whether the call is making a return connection or a normal connection, and if the call is making a return connection, determines which call management number is the call of the other party. If the result of the determination is that the call is making a normal connection, the CP
U70 performs a conventional cutting process. On the other hand, as a result of the determination, if the loopback connection is performed, a disconnection process is performed between the mobile station for the call and the mobile station for the call of the call management number of the other party.

In FIG. 5, the call management number of the mobile station 9 is described in the item of the communication destination call management number of the call information corresponding to the mobile station 8, so that the CPU 70 It is determined that a return connection is established with the call of the mobile station 9,
The mobile station 8 and the mobile station 9 are disconnected. Specifically, CP
U70 transmits a release signal corresponding to the disconnection signal to mobile station 8, and receives a release completion signal from mobile station 8 (S50).
4, S505). Thereby, the mobile station 8 and the radio base station 1
The wireless line with 00 is disconnected.

When the CPU 70 transmits a disconnection signal to the mobile station 9 and receives a release signal from the mobile station 9, it transmits a release completion signal to the mobile station 9 (S506-508). As a result, the wireless line between the wireless base station 100 and the mobile station 9 is disconnected. In this way, when two mobile stations connected to each other by a loopback connection disconnect, the CPU 70 performs disconnection processing on the two mobile stations. <Second Embodiment> A radio base station according to a second embodiment will be described below with reference to the drawings.

The radio base station according to the second embodiment (hereinafter, referred to as a base station)
The wireless base station 200 is replaced by C instead of the CPU 70.
PU 270, and the other components are the radio base station 1
Same as 00. The radio base station 200 has a CPU
Due to the provision of 270, the timing at which the loopback connection is performed in the connection sequence shown in FIG.

FIG. 6 shows a connection sequence when the mobile station 8 and the mobile station 9 existing in the area of the radio base station 200 communicate with each other. In the figure, it is assumed that the mobile station 8 is the calling mobile station and the mobile station 9 is the called mobile station.
Note that the same numbers (S401 to S413) as those in FIG. CPU 270
When a call setting acceptance signal is returned from the mobile station 9 in S413, the mobile station 9 refers to the shortcut flag in the call management table 60 to detect a call that can be connected back.
Here, these calls are detected because the shortcut flags of the call information of the mobile stations 8 and 9 are turned on.

CPU 270 causes ADPCM processing section 40 to loop back and connect the radio line between mobile station 8 and mobile station 9 (S614). Next, the CPU 270 disconnects the connection between the mobile station 8 and the wireless base station 200 corresponding to the call of the mobile station 9 and the exchange (S615 to S620). On the other hand, the mobile station 9 that has transmitted the call setting acceptance signal to the radio base station 200 transmits a paging signal to the mobile station 8 via the radio base station 200 (S621, S622).

When the user goes off-hook to mobile station 9, mobile station 9 transmits a response signal to radio base station 200 (S623). The CPU 270 returns a response confirmation signal for the response signal to the mobile station 9 and transfers the response signal to the mobile station 8 (S624, S625). Mobile station 8
Returns a response confirmation to the wireless base station 200, the mobile station 8
Communication is established by loopback connection of the route between the wireless base station 200 and the mobile station 9 (S627).

As described above, in the connection sequence of FIG. 4, after the communication via the exchange is established once, the mobile station 8—the radio base station 200—the exchange—the radio base station 200—the mobile station 9 Although the connection with the wireless base station 200 has been cut off and switched to the loopback connection, in the connection sequence of FIG. 6, the mobile station 8 and the wireless base station 20 are connected.
When the call setup is established between 0, the exchange, the radio base station 200, and the mobile station 9, the connection between the exchange and the radio base station 200 is disconnected. After that, when the mobile station 9 responds to the call, the communication by the loopback connection is performed. Establish. <Third Embodiment> A radio base station according to a third embodiment will be described below with reference to the drawings.

The radio base station according to the third embodiment (hereinafter, referred to as a base station)
The radio base station 300) is replaced by C
PU 370, and other components include the radio base station 10
Same as 0. The radio base station 300 includes the CPU 370, and is configured to switch between the normal connection and the loopback connection according to the result of the mobile station moving in the area at the time of handover.

FIG. 7 shows that the mobile station 8 in the area of the radio base station 300 and the mobile station 9 in the area of the radio base station 301 communicate with each other via a network, and thereafter, the communication is continued. 3 shows a connection switching sequence when the mobile station 9 has handed over to the area of the radio base station 300. Here, the configuration of the wireless base station 301 is the same as that of the wireless base station 30.
Same as 0. However, C that the wireless base station 301 has
PU having the PU and the call management table in the radio base station 300
CP for distinguishing from PU 370 and call management table 60
U371 and call management table 61.

While the mobile station 8 in the area of the radio base station 300 and the mobile station 9 in the area of the radio base station 301 are communicating via the network, the mobile station 9 performs handover by movement. When a handover request is transmitted to the wireless base station 301 (S701, 702), the CPU 371
Performs the processing shown in the flowchart of FIG. Specifically, the CPU 371 in FIG.
It is determined whether the shortcut flag of the call information of the mobile station 9 is on or off (S801). That is, it is determined whether or not the mobile station 9 is performing communication by loopback connection.

Here, since the shortcut flag is turned off, the CPU 371 performs a normal handover process. Here, the normal handover processing means that the CPU 371 transmits a handover instruction to the mobile station 9 (S704). The CPU 371 deletes the call information of the mobile station 9 from the call management table 61 (S
605).

The mobile station 9 having received the handover instruction from the radio base station 301 transmits a call setup request (handover) to the radio base station 300 (S706). CPU
370 creates call information corresponding to the mobile station 9 based on the call setup message transmitted by the call setup request, and adds it to the call management table 60 (S707).

CPU 370 transmits a call setting acceptance signal to mobile station 9 (S708). The CPU 370 searches the call management table 60 to determine whether a call related to each piece of call information can be looped back and sets the shortcut flag to ON for the call information of the call that can be made (S709). ). Here, it is determined that the call of the mobile station 9 and the mobile station 8 can be connected back, and the respective shortcut flags are set to ON.

CPU 370 transfers the call setting request transmitted from mobile station 9 to the exchange (S710). CP
When a call setting acceptance signal corresponding to the call setting request is returned from the exchange and a response signal is transmitted (S710, S711), U370 returns a response acknowledgment signal to the exchange (S714). The response signal from the exchange is transferred (S715).

On the other hand, in the radio base station 301, a disconnection signal is transmitted from the exchange to disconnect the connection between the exchange and the radio base station 301.
01 and the exchange (S716, S7).
18, S720), disconnecting the connection between the wireless base station 301 and the mobile station 9 (S717, S719, S72).
1).

In S715, the mobile station 9 sets the radio base station 3
00, the mobile station 9-
Communication is established by a connection path of the wireless base station 300, the switch, the wireless base station 300, and the mobile station 8. CPU 370
Refers to the call information in the call management table 60 (S72).
3), two calls that can be connected back to each other are detected, and if detected, the ADPCM processing unit 40 performs the back connection (S724). Here, since the mobile station 8 and the mobile station 9 can be looped back to each other, the radio lines for these calls are connected in the ADPCM processing unit 40.

The CPU 370 disconnects the connection between the radio base station 300 and the exchange for the call of the mobile station 9 (S7).
25-S728). As a result, the CPU 370 determines that the exchange for the call of the mobile station 8 from the exchange and the radio base station 300
Since the disconnection signal supporting the disconnection is transmitted, the connection is disconnected (S729 to S731). As a result, the mobile station 8 and the mobile station 9 are connected to the mobile station 8 and the radio base station by the return connection. Communication on the connection path between the station 300 and the mobile station 9 is established (S732).

FIG. 9 shows a connection when the mobile station 9 moves to the area of the radio base station 301 while the mobile station 8 and the mobile station 9 are performing communication by loopback connection under the radio base station 300. 3 shows a switching sequence. When the mobile station 9 communicating with the mobile station 8 by the loopback connection transmits a handover request to the wireless base station 300 to perform a handover (S902), the CPU 370 of the wireless base station 300 performs the processing in FIG.

More specifically, the CPU 370 determines whether the shortcut flag in the call information of the mobile station 9 is on or off (S801). Thereby, the mobile station 9
It is determined whether or not the call is making a return connection. Here, since it is determined to be on, the CPU 370
Determines whether the call flag in the call information is on or off (S803). Thereby, the mobile station 9
Is a calling mobile station or a called mobile station.

As a result of the determination, if the outgoing call flag is on,
Since the mobile station 9 is the calling mobile station, the CPU 370
A call setting request is transmitted to the exchange using the call setting message in the call information of the mobile station 9. On the other hand, if the result of the determination is that the outgoing call flag is off, the mobile station 9 is the called mobile station, and the CPU 370 determines the call management number recorded in the communication destination call management number in the call information of the mobile station 9. Read the number. This call management number is the call management number of the mobile station 8 communicating with the mobile station 9. CPU 370 transmits a call setup request to the exchange using the call setup message of the call information corresponding to the read call management number (S903). The processing in S903 connects the wireless base station 300 and the exchange by transmitting a call setting request using the call setting message of the calling mobile station of the two mobile stations that have been performing communication through the loopback connection. .

S90 between the radio base station 300 and the exchange
By exchanging the call control signals shown in Steps S911 to S911, the communication of the connection route of the mobile station 9, the radio base station 300, the switch, the radio base station 300, and the mobile station 8 becomes possible.
The CPU 370 instructs the ADPCM processing unit 40 to release the loopback connection between the mobile station 8 and the mobile station 9 and switch to the normal connection (S912). By this switching, communication between the mobile station 9 and the mobile station 8 is established on the connection route of the mobile station 9-the radio base station 300-the switch-the radio base station 300-the mobile station 8 (S913).

The CPU 370 transmits a handover instruction which is a response to the handover request to the mobile station 9 (S91).
4), the call information of the mobile station 9 is deleted from the call management table 60 (S915). Upon receiving the handover instruction from 370, the mobile station 9 transmits a call setup request for handover to the wireless base station 301 (S916), and performs a call setup process with the wireless base station 301. The communication is established by the connection path of the mobile station 9-the radio base station 301-the switching system-the radio base station 300-the mobile station 8.

[0067]

The radio base station of the present invention has a radio interface for connecting a mobile station wirelessly and a telephone network interface, and is a radio base station for connecting a radio-connected mobile station to a telephone network, Determining means for determining whether the calling mobile station and the corresponding called mobile station are present in the area of the local station; and, when the determining means determines that the mobile station is present, the two Connecting means for mutually connecting the wireless lines of the mobile station via a wireless interface.

According to this configuration, the calling mobile station existing in the area of the radio base station and the corresponding called mobile station are connected to each other via the radio line without passing through the telephone network. Therefore, traffic is not wastefully occupied in the exchange of the telephone network, so that the load on the exchange is reduced, which has the effect of reducing the traffic volume in the telephone network. Further, even when a failure occurs in the telephone network, the calling mobile station and the called mobile station can communicate via the wireless base station, and there is no call loss that communication cannot be performed. effective.

Further, the determination means includes, for each mobile station wirelessly connected, a call management table for storing a record in which the number of the calling mobile station and the number of the called mobile station are associated with each other; Updating means for updating the call management table based on the call control information notified from the mobile station or the telephone network, wherein the numbers of the calling mobile stations match between the records of the call management table, and The determination is made by detecting two records having the same mobile station number.

According to this configuration, since the call management table has been conventionally used in the radio base station, the determination means can make the determination by effectively using the conventional call management table. There is an effect that can be. Further, the call control information includes a call request from a mobile station in the area,
It is a call request to a mobile station in the area, or a recall request from a mobile station that has moved into the area for handover.

Further, the determination means is configured to make a determination when the call management table is updated by the update means. The radio base station has a radio interface for connecting mobile stations wirelessly and a telephone network interface, and is a radio base station for connecting a radio connected mobile station to a telephone network. Determining means for determining whether or not the mobile stations are communicating with each other; and, when determining that the mobile stations are communicating with each other, connecting the wireless lines of the two mobile stations to each other via a wireless interface, Connection means for disconnecting the connection to the network.

According to this configuration, the calling mobile station existing in the area of the radio base station and the corresponding called mobile station are connected to each other via the radio line without passing through the telephone network. Therefore, traffic is not wastefully occupied in the exchange of the telephone network, so that the load on the exchange is reduced, which has the effect of reducing the traffic volume in the telephone network. Further, even when a failure occurs in the telephone network, the calling mobile station and the called mobile station can communicate via the wireless base station, and there is no call loss that communication cannot be performed. effective.

The radio base station has a radio interface for connecting the mobile station by radio and a telephone network interface, and is a radio base station for connecting the radio-connected mobile station to the public network. When receiving a call request, determining means for determining whether the called mobile station specified in the call request is within the wireless area of the wireless base station, and determining that the mobile station is present Connecting means for mutually connecting the wireless line of the calling mobile station and the wireless line of the called mobile station via a wireless interface.

According to this configuration, the calling mobile station existing in the area of the radio base station and the corresponding called mobile station are connected to each other via the radio line without passing through the telephone network. Therefore, traffic is not wastefully occupied in the exchange of the telephone network, so that the load on the exchange is reduced, which has the effect of reducing the traffic volume in the telephone network. Further, even when a failure occurs in the telephone network, the calling mobile station and the called mobile station can communicate via the wireless base station, and there is no call loss that communication cannot be performed. effective.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a wireless base station according to the present embodiment.

FIG. 2 is a block diagram showing a detailed configuration of an ADPCM processing unit 40.

FIG. 3 shows an example of storage contents of a call management table 60.

FIG. 4 is a connection sequence when the mobile station 8 and the mobile station 9 existing in the area of the wireless base station 100 communicate with each other.

FIG. 5 is a diagram illustrating a disconnection signal between the mobile station 8 and the mobile station 9 existing in the area of the wireless base station 100 and communicating with each other through a loopback connection, and the mobile station 8 transmits a disconnection signal to the wireless base station 100; 11 shows a disconnection sequence in the case of transmitting a.

FIG. 6 is a connection sequence when the mobile station 8 and the mobile station 9 existing in the area of the radio base station 200 communicate with each other.

FIG. 7 shows a mobile station 8 in the area of the wireless base station 300 and a mobile station 9 in the area of the wireless base station 301 communicating with each other via a network. 9 shows a connection switching sequence when handover to the area of the wireless base station 300 is performed.

FIG. 8 is a flowchart of processing performed when a CPU 371 receives a handover request.

FIG. 9 shows a state in which the mobile station 8 and the mobile station 9 are performing communication by loopback connection under the radio base station 300.
7 shows a connection switching sequence in the case where has moved to the area of the wireless base station 301.

FIG. 10 is a diagram showing a schematic configuration of a mobile communication system.

[Explanation of symbols]

 Reference Signs List 10 antenna 20 radio section 30 TDMA / TDD processing section 40 ADPCM processing section 50 telephone network I / F 60 call management table 70 CPU

Claims (6)

[Claims] A wireless base station having a wireless interface for connecting a mobile station wirelessly and a telephone network interface, and connecting a wirelessly connected mobile station to a telephone network, comprising a calling mobile station and a corresponding mobile station Determining means for determining whether a called mobile station to be called is present in the area of its own station;
Connection means for mutually connecting the radio lines of two mobile stations via a radio interface. 2. A call management table for storing a record in which a number of a calling mobile station and a number of a called mobile station are associated with each other for each mobile station connected wirelessly, Updating means for updating the call management table based on the call control information notified from the mobile station or the telephone network, wherein the numbers of the calling mobile stations match between the records of the call management table, and 2. The radio base station according to claim 1, wherein the determination is made by detecting two records having the same number of the calling mobile station. 3. The call control information includes a call request from a mobile station in the area, a call request to a mobile station in the area, or a recall request from a mobile station that has moved into the area for handover. The radio base station according to claim 2, wherein 4. The radio base station according to claim 3, wherein said determination means makes a determination when a call management table is updated by said update means. 5. A wireless base station having a wireless interface for wirelessly connecting a mobile station and a telephone network interface and connecting a wirelessly connected mobile station to a telephone network, wherein the two mobile stations are wirelessly connected. Determining means for determining whether or not the stations are communicating with each other; and, if it is determined that the stations are communicating with each other, connecting the wireless lines of the two mobile stations to each other via a wireless interface; And a connection means for disconnecting the connection with the radio base station. 6. A wireless base station having a wireless interface for connecting a mobile station wirelessly and a telephone network interface and connecting a wirelessly connected mobile station to a public network, wherein the wireless base station receives a call request from the mobile station. Receiving means for determining whether or not the called mobile station specified in the call request is present in the wireless area of the wireless base station; and A connection means for mutually connecting the wireless line of the mobile station on the side and the wireless line of the mobile station on the called side via a wireless interface.