JP2001238264A - Mobile communication system and direct speech communication method used for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mobile communication system that can relieve the load of a network and reduce the load of charging imposed on users by allowing mobile wireless stations to directly make communications (speech communication) not via the networks. SOLUTION: In the speech communication between mobile wireless stations 3, 4, a wireless base station management station 1 uses an inter-mobile-wireless-station distance estimation section 12 to retrieve the positions of the mobile wireless stations 3, 4 via a wireless base stations 1 to estimate the distance between the mobile wireless stations 3, 4 and an estimation section 13 for estimating electric field strength or the like estimates electric field strength or the like. When an inter-mobile-wireless- station speech communication control section 11 determines that the mobile wireless stations 3, 4 are within a distance at which the mobile wireless stations 3, 4 can sufficiently make a speech communication, the control section 11 informs the mobile wireless stations 3, 4 to start direct speech communication mode transmitter-receiver sets 32, 42, designates a communication channel between the mobile wireless stations 3, 4 and makes a notice of a wireless frequency and a connection code or the like, and the mobile wireless stations 3, 4 take wireless synchronization and signal synchronization according to a direct communication procedure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system and a direct communication method used therewith, and more particularly to a communication method between mobile radio stations in a mobile communication system.

[0002]

2. Description of the Related Art Conventionally, in a mobile communication system,
The mobile radio station has a small radio output, a radio base station called a pico cell for accommodating the mobile radio station, and a radio control station for managing a plurality of radio base stations having adjacent service areas.

In this mobile communication system, when a mobile radio station moving within a service area at a high speed moves to another area adjacent to the service area of the radio base station, the mobile radio station moves between the mobile radio station and the radio base station. , The location registration procedure is frequently performed, so that the radio channel (CH) becomes tight, or the call quality is degraded because the call is temporarily terminated and a new call connection is made when moving from one service area to another.

[0004] In order to avoid this, a plurality of radio base stations having pico cell service areas are grouped and managed, and when moving to a service area of another group, a location registration procedure is performed in the conventional manner. By simplifying the location registration procedure of a moving mobile radio station, the use of a radio channel is suppressed, the radio frequency of the entire system is used effectively, and the line quality of the mobile radio station during a call is improved.

[0005] Conventional mobile phone services and CDMA (Co
de Division Multiple Access
ss) In a communication system, there is a position search system in which a mobile radio station uses a reception electric field, a reference time, a radio wave arrival time, and the like using downlink radio waves or signals of a plurality of radio base stations. This position search system is disclosed in
38951, JP-A-10-48322 and JP-A-7-181242.

[0006]

However, in the conventional position search system, only the position of the mobile base station in the network is supplemented, and the position of the specific mobile station is separately requested by the contractor to search. Just do the service.

[0007] Therefore, an object of the present invention is to solve the above-mentioned problems and to enable direct communication (call) between mobile radio stations without going through a network, thereby reducing the load on the network and the burden on the user. And a direct communication method used for the mobile communication system.

[0008]

A mobile communication system according to the present invention is a mobile communication system for communicating between a plurality of mobile radio stations via a radio base station under the control of a radio base station management station. Determining means for determining whether direct communication is possible between the plurality of mobile wireless stations without passing through the wireless base station, and the direct communication is performed when the determining means determines that the direct communication is possible. Communication control means for instructing each of the plurality of mobile radio stations, the radio base station management station comprising: a dedicated communication dedicated circuit for performing the direct communication in response to an instruction from the communication control means; Prepared for each.

A direct communication method according to the present invention is a direct communication method for a mobile communication system in which communication is performed between a plurality of mobile radio stations via a radio base station under the control of a radio base station management station. Determining whether direct communication is possible between the plurality of mobile radio stations without going through a station, and instructing the direct call to each of the plurality of mobile radio stations when the direct communication is determined to be possible In the radio base station management station, and in each of the plurality of mobile radio stations, activating a dedicated circuit dedicated to direct communication in response to an instruction from the communication control means.

In other words, the mobile communication system of the present invention supplements the mobile radio station by a position search system in addition to the ordinary call between the mobile radio station and the network according to the calling / incoming call procedure. If this is the case, the dedicated circuit of the mobile radio station is activated, and after establishing wireless synchronization and communication synchronization, the call is switched to a two-way call.

The mobile radio station is equipped with a dedicated receiving circuit for communication between mobile radio stations, performs a two-party call procedure according to an instruction from the radio base station, notifies the network when the procedure is completed, and moves to the network side when switching permission is given. Switch to two-party calling between wireless stations. When the call between the two parties ends, the network side is notified.

In a CDMA communication system, one or a plurality of radio base stations share a service area. Also, C
In a DMA communication system, one base station always knows the distance (propagation delay time) from a mobile radio station during a call.

In operation of this CDMA communication system, two or three radio base stations have one mobile radio station in a service area. Although the direction can be limited to some extent from one radio base station, it is not possible to determine the exact position. Therefore, the position is determined by managing the distances (propagation delay times) from the plurality of radio base stations by the radio base station management station.

According to this method, if it is determined that two mobile radio stations are communicating and the communication quality can be maintained, the mobile radio station is contacted and the two parties communicate with each other without passing through the radio base station.

Since a reference timing is required, a line between mobile radio stations is opened by another circuit while receiving a downlink signal from the nearest radio base station. At the end of the call, the end of the call is notified to the radio base station. Even if the line is disconnected during a call, the call is reported to the wireless base station as a call termination. Otherwise, since they are disconnected from the network side, they cannot respond if there is an incoming call even during a call.

Thus, in a CDMA communication system, the position of a mobile radio station during a call is searched for, the distance between two mobile radio stations is calculated when a call is made between the mobile radio stations, and if the distance is short, the mobile radio station does not go through a radio base station. By making a call directly between two parties, C
Since the communication line from the DMA communication system is disconnected,
As the network becomes lighter and the subscriber is not charged, it is financially advantageous.

[0017]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a mobile communication system according to one embodiment of the present invention. In FIG. 1, a mobile communication system according to an embodiment of the present invention controls a radio base station (B
The radio communication is performed between the mobile radio station (MS-A) 3 and the mobile radio station (MS-B) 4 via the TS 2.

The radio base station management station 1 includes a mobile radio station communication control unit 11, a mobile radio station distance estimation unit 12, and an electric field strength etc. estimation unit 13. Units 31, 41 (the call control unit 41 is not shown);
Direct communication mode transceivers 32 and 42 (the direct communication mode transceiver 42 is not shown) are provided.

To perform communication (call) between the mobile radio stations 3 and 4, the mobile radio stations 3 and 4 desire direct communication (call).
Also, the distance must allow stable communication (call) between the two parties. Therefore, the radio base station management station 1 (network side) searches the mobile radio stations 3 and 4 via the radio base station 2 for the positions of the mobile radio stations 3 and 4 to which direct communication is desired by the mobile radio station distance estimation unit 12, and , 4 are estimated.

When the distance between the mobile radio stations 3 and 4 can be estimated, the radio base station management station 1 estimates the electric field strength and the like by the electric field strength estimating section 13. When it is determined that the communication distance between the mobile radio stations 3 and 4 is sufficient, the mobile radio station communication control unit 11 activates the direct communication mode transceivers 32 and 42 to the mobile radio stations 3 and 4 that desire direct communication. Notify you to

Thereafter, the inter-mobile radio station communication control section 11 issues a communication channel designation between the mobile radio stations 3 and 4, a radio frequency, a connection code, and the like.
Radio synchronization and signal synchronization are established between the mobile radio stations 3 and 4 according to the direct communication procedure between them.

When the mobile radio stations 3 and 4 receive the notification of the preparation for direct communication between mobile radio stations from the radio base station management station 1, they activate the direct communication mode transceivers 32 and 42 and receive the notification from the radio base station management station 1. The received radio frequency and connection code are set in the direct call mode transceivers 32 and 42 to synchronize radio and signal with each other.

When the communication between the mobile radio stations 3 and 4 is completed and the connection procedure between the mobile radio stations is completed, the mobile radio station 3 that has made the call sends a direct call to the radio base station management station 1 between the mobile radio stations. Notifies that the communication procedure has been completed. The mobile radio station distance estimating unit 12 estimates the distance and the electric field strength estimating unit 1.
Since the estimation of the electric field strength and the like by 3 is a technique well known to those skilled in the art, the detailed method and the like will be omitted.

FIGS. 2 and 3 are diagrams showing communication between the radio base station 2 and the mobile radio stations 3 and 4 in FIG. In FIG.
The interface in the radio section is performed on the radio channel A and format D for the downlink signal from the radio base station 2 to each of the mobile radio stations 3 and 4, and the uplink direction from each of the mobile radio stations 3 and 4 to the radio base station. It is assumed that the signal is transmitted in the radio channel B and the format U.

In FIG. 3, the direct call mode transceivers 32 and 42 of the mobile radio stations 3 and 4 use the radio channel D and the format U for the signal from the mobile radio station 3 to the mobile radio station 4, The signal going from 4 to the mobile radio station 3 is radio channel C and format U.

The mobile radio station 3 also multiplexes and transmits the radio channel B and format U for a short message to inform the radio base station 2 that a call is in progress. The short message is not demodulated by the mobile radio station 4.

FIG. 4 is a sequence chart showing a location registration procedure of the mobile communication system according to one embodiment of the present invention. In FIG. 4, when the mobile radio stations 3 and 4 transmit a location registration request to the radio base station 2, the radio base station 2 transmits the location registration request to the radio base station management station 1. Upon receiving the location registration request, the wireless base station management station 1 transmits an authentication request to the wireless base station 2. The radio base station 2 is a radio base station management station 1
Is transmitted to the mobile radio stations 3 and 4.

When receiving the authentication request from the radio base station 2, the mobile radio stations 3 and 4 transmit an authentication response to the request to the radio base station 2. The wireless base station 2 transmits an authentication response from the mobile wireless stations 3 and 4 to the wireless base station management station 1. Upon receiving the authentication response, the wireless base station management station 1 accepts location registration from the mobile wireless stations 3 and 4 and transmits a notification to that effect (location registration acceptance) to the wireless base station 2. The wireless base station 2 transmits a position registration reception from the wireless base station management station 1 to the mobile wireless stations 3 and 4.
Thereby, the position registration of the mobile radio stations 3 and 4 is performed.

FIGS. 5 and 6 are sequence charts showing a normal call connection procedure in the mobile communication system according to one embodiment of the present invention. With reference to FIGS. 1, 5 and 6, a normal call connection procedure of the mobile communication system according to one embodiment of the present invention will be described.

When the mobile radio station 3 goes off-hook and transmits a call request to the radio base station 2, the radio base station 2 transmits a call request A from the mobile radio station 3 to the radio base station management station 1.
Upon receiving the call request A, the wireless base station management station 1 transmits an authentication request A to the wireless base station 2. When receiving the authentication request A from the wireless base station management station 1, the wireless base station 2 transmits an authentication request to the mobile wireless station 3.

When the mobile radio station 3 receives the authentication request from the radio base station 2, it sends an authentication response to the authentication request to the radio base station 2. The wireless base station 2 transmits an authentication response A from the mobile wireless station 3 to the wireless base station management station 1. Upon receiving the authentication response A, the wireless base station management station 1 transmits the wireless channel designation A to the wireless base station 2, and the wireless base station 2 sends the wireless channel designation to the mobile wireless station 3.

Thereafter, the wireless base station 2 transmits a notification of a wireless electric field / error or the like to the mobile wireless station 3. When receiving the notification of the wireless electric field / error from the wireless base station 2, the mobile wireless station 3 transmits a wireless information confirmation to the wireless base station 2.

The radio base station management station 1 transmits a radio channel designation A
, The connection A is transmitted to the radio base station 2, and the radio base station 2 transmits the connection to the mobile radio station 3. When receiving the connection from the radio base station 2, the mobile radio station 3 transmits a connection response to the connection to the radio base station 2. Upon receiving the connection response from the mobile radio station 3, the radio base station 2 transmits a connection confirmation A to the radio base station management station 1. Upon receiving the connection confirmation A, the radio base station management station 1 transmits a call B to the radio base station 2, and the radio base station 2 transmits the call to the mobile radio station 4.

When the mobile radio station 4 transmits a report such as a received electric field to the radio base station 2 in response to the call from the radio base station 2, the radio base station 2 transmits a call response B to the radio base station management station 1. . Then, the radio base station management station 1 transmits an authentication request B to the radio base station 2, and the radio base station 2 transmits an authentication request to the mobile radio station 4.

Upon receiving the authentication request from the radio base station 2, the mobile radio station 4 transmits an authentication response to the authentication request to the radio base station 2. The wireless base station 2 transmits an authentication response B from the mobile wireless station 4 to the wireless base station management station 1. Upon receiving the authentication response B, the wireless base station management station 1 transmits a wireless channel designation B to the wireless base station 2, and the wireless base station 2 sends a wireless channel designation to the mobile wireless station 4.

The radio base station management station 1 transmits a radio channel designation B
Is transmitted, the radio information notification B is transmitted to the radio base station 2, and the radio base station 2 transmits a notification such as a radio electric field to the mobile radio station 4. When receiving the notification of the wireless electric field or the like from the wireless base station 2, the mobile wireless station 4 transmits wireless information confirmation to the wireless base station 2. When receiving the radio information confirmation from the mobile radio station 4, the radio base station 2 transmits a radio information confirmation B to the radio base station management station 1. Upon receiving the radio information confirmation B, the radio base station management station 1 transmits the connection B to the radio base station 2, and the radio base station 2 transmits the connection to the mobile radio station 4.

On the other hand, when receiving the connection from the radio base station 2, the mobile radio station 4 transmits a connection response to the connection to the radio base station 2. Upon receiving the connection response from the mobile radio station 4, the radio base station 2 transmits a connection response B to the radio base station management station 1. Thus, a call between the mobile radio stations 3 and 4 is established.

On the other hand, when the mobile radio station 3 goes on-hook and transmits a call termination request to the radio base station 2, the radio base station 2 transmits a call termination request A from the mobile radio station 3 to the radio base station management station 1. . Upon receiving the call termination request A from the mobile radio station 3, the radio base station management station 1 transmits a call termination reception A to the radio base station 2. Upon receiving the call termination reception A from the radio base station management station 1, the radio base station 2 transmits a call termination reception to the mobile radio station 3.

After transmitting the end of call reception A, the radio base station management station 1 transmits a communication channel release notification A to the radio base station 2, and the radio base station 2 transmits a communication channel release notification to the mobile radio station 3. . After transmitting the communication channel release notification A, the radio base station management station 1 transmits the communication channel release notification B.
Is transmitted to the radio base station 2, and the radio base station 2 transmits a communication channel release notification to the mobile radio station 4. Mobile radio stations 3, 4
Transmits a communication channel release response to the radio base station 2 in response to the communication channel release notification from the radio base station 2.

Upon receiving the communication channel release response from the mobile radio stations 3 and 4, the radio base station 2 transmits a radio channel disconnection notification to the mobile radio stations 3 and 4, respectively. Upon receiving the wireless channel disconnection notification from the wireless base station 2, the mobile wireless stations 3 and 4 transmit a wireless channel disconnection response to the wireless base station 2, respectively. When receiving the radio channel disconnection response from the mobile radio stations 3 and 4, the radio base station 2 transmits the radio channel disconnection response A and the radio channel disconnection response B to the radio base station management station 1.
Send to As a result, the call between the mobile radio stations 3 and 4 ends.

FIGS. 7 and 8 show the radio base station management station 1 of FIG.
9 is a flowchart showing the processing operation of FIG.
0 is a flowchart showing the processing operation of the mobile radio stations 3 and 4 in FIG. FIGS. 11 to 14 are sequence charts showing a two-party call connection procedure in the mobile communication system according to one embodiment of the present invention.

The operation of the mobile communication system according to one embodiment of the present invention will be described with reference to FIG. 1 and FIGS. Hereinafter, a case where the mobile radio station 3 originates a call and the mobile radio station 4 receives a call will be described.

When the mobile radio station 3 makes a call, the radio base station management station 1 completes the connection with the mobile radio station 3 (step S1 in FIG. 7), and then completes the connection with the mobile radio station 4 (FIG. 7). Step S2). Thereafter, the mobile radio station 3 starts talking with the mobile radio station 3 via the radio base station 2 (steps S3 in FIG. 7, steps S21 and S22 in FIG. 9). The connection procedure during this time is the same as the normal call connection procedure described above. When direct communication (call) is not performed between the mobile radio stations 3 and 4 (step S4 in FIG. 7 and step S23 in FIG. 9), normal call connection is continued as it is.

On the other hand, when performing direct communication (call) between the mobile radio stations 3 and 4 (step S4 in FIG. 7 and step S23 in FIG. 9), the mobile radio stations 3 and 4 desire direct communication (call). And the distance between the two must be a distance at which stable communication (call) can be performed. Therefore, the radio base station management station 1
The (network side) searches the positions of the mobile radio stations 3 and 4 that desire direct communication via the radio base station 2 and estimates the distance between the mobile radio stations 3 and 4 (step S in FIG. 7).
5). In this case, the radio base station management station 1
If the distance between the four exceeds a predetermined value, the normal call connection is continued.

When estimating the distance between the mobile radio stations 3 and 4, the radio base station 2 receives the broadcast information such as the service content from the radio base station management station 1 and transmits the broadcast information to the mobile radio station. Transmit to stations 3 and 4. The mobile radio station 3 transmits a location registration request to the radio base station 2 in response to the broadcast information.

Upon receiving the location registration request, the radio base station 2 transmits the location registration request and the received electric field / distance / propagation delay time notification A to the radio base station management station 1.
Sends a position registration confirmation to the mobile radio station 3.

Thereafter, when the radio base station 2 receives the location registration notification request B from the radio base station management station 1, the radio base station 2 transmits the location registration notification request to the mobile radio station 4. The mobile radio station 4 transmits a location registration notification to the radio base station 2 in response to the location registration notification request.

Upon receiving the location registration notification, the radio base station 2 transmits a location registration notification and a received electric field / distance / propagation delay time notification B to the radio base station management station 1. Accordingly, the radio base station management station 1 determines whether the mobile radio stations 3 and 4 have a two-party communication function, whether the mobile radio stations 3 and 4 are in a close area, whether the distance between the two is sufficiently short, or whether It is determined whether inter-call is possible (see FIG. 11).

If the distance between the mobile radio stations 3 and 4 is equal to or less than a predetermined value, the radio base station management station 1 estimates the electric field strength and the like and determines that the communication (communication) distance is sufficient. The mobile radio stations 3 and 4 that desire direct communication are notified to activate the direct call mode transceivers 32 and 42 (step S6 in FIG. 7).

Subsequently, the radio base station management station 1 designates a communication channel between the mobile radio stations 3 and 4, issues a radio frequency, a connection code, and the like, and prepares for a direct call between the mobile radio stations (MS). (Step S7 in FIG. 7).
Radio synchronization and signal synchronization are established between the mobile radio stations 3 and 4 in accordance with a direct communication procedure between the mobile radio stations 3 and 4.

When the mobile radio stations 3 and 4 receive the notification of the preparation for direct communication between mobile radio stations from the radio base station management station 1, they activate the direct call mode transceivers 32 and 42 (step S in FIG. 9).
24), the radio frequency and the connection code notified from the radio base station management station 1 are set (step S25 in FIG. 9), and radio synchronization and signal synchronization are established with each other (step S26 in FIG. 9).

When the connection procedure between the mobile radio stations is completed, the mobile radio station 3 that has made the call notifies the radio base station management station 1 that the direct communication procedure between the mobile radio stations has been completed (step in FIG. 9). S27, S28).

That is, when the two-party communication preparation notification A is sent from the wireless base station management station 1, the wireless base station 2 transmits the two-party communication preparation notification to the mobile wireless station 3. The mobile radio station 3 activates the direct call mode transceiver 32 in response to the two-party communication preparation notification, and transmits a circuit activation response to the radio base station 2.

Upon receiving the circuit activation response, the radio base station 2 transmits a circuit activation response A to the radio base station management station 1, and when the radio channel designation A is sent from the radio base station management station 1, the radio base station 2 transmits the circuit activation response A. The channel designation is transmitted to the mobile radio station 3. When the wireless base station 2 receives the wireless information notification A from the wireless base station management station 1, the wireless base station 2 sends the wireless information notification to the mobile wireless station 3. The mobile radio station 3 transmits a radio information confirmation to the radio base station 2 in response to the radio information notification. Upon receiving the wireless information confirmation, the wireless base station 2 transmits the wireless information confirmation A to the wireless base station management station 1.

Similarly, when the radio base station 2 receives the radio channel designation B from the radio base station management station 1, the radio base station 2 transmits to the mobile radio station 4 a radio channel designation / two-party communication preparation.
Further, when the radio base station 2 receives the radio information notification B from the radio base station management station 1, the radio base station 2 transmits the radio information notification to the mobile radio station 4. The mobile radio station 4 activates the direct call mode transceiver 42 in response to the radio channel designation / two-party communication preparation, and transmits a radio channel designation / two-party communication preparation response to the radio base station 2. Upon receiving the wireless channel designation / two-party communication preparation response, the wireless base station 2 transmits a wireless information response B to the wireless base station management station 1.

Thereafter, when the radio base station 2 receives the traffic channel designations A and B from the radio base station management station 1, the radio base station 2 transmits the traffic channel designations to the mobile radio stations 3 and 4. The mobile radio stations 3 and 4 set a communication channel in response to the communication channel designation, and transmit a communication channel preparation completion notification to the radio base station 2, respectively. Upon receiving the communication channel preparation completion notification, the radio base station 2 transmits communication channel preparation completion notifications A and B to the radio base station management station 1 (see FIG. 12).

When the radio base station management station 1 is notified by the mobile radio station 3 that the direct communication procedure between mobile radio stations has been completed, the radio base station management station 1 determines that the preparation for direct communication is complete and sends the transmission to the mobile radio stations 3 and 4 to the direct communication channel. (Steps S8 and S8 in FIG. 8)
9). Further, when the mobile radio station 3 can talk with the mobile radio station 4 (step S27 in FIG. 9), the mobile radio station 3 notifies the radio base station management station 1 that the mobile radio stations 3 and 4 have entered the direct call mode. (Step S28 in FIG. 10).

When the radio base station management station 1 is notified that the mobile radio stations 3 and 4 have entered the direct communication mode (step S10 in FIG. 8), a direct communication is performed between the mobile radio stations 3 and 4. While the call is being made (step S11 in FIG. 8), it is monitored whether or not the mobile radio station 3 is notified that a call is being made directly (FIG. 8).
Step S12). Here, a method of notifying during direct call using a short message or the like can be considered.

While the mobile radio station 3 is in direct communication with the mobile radio station 4 (step S29 in FIG. 10), the direct radio communication with the mobile radio station 4 is not completed (step S29 in FIG. 10). S30), it notifies the wireless base station management station 1 that it is directly in a call (step S31 in FIG. 10).

That is, when the wireless base station management station 1 receives the two-way communication channel synchronization acquisition A from the wireless base station management station 1, the wireless base station 2 transmits to the mobile wireless station 3 a start of transmission and reception of the two-way communication channel. The mobile radio station 3 responds to the start of the transmission / reception of the two-party communication channel, and the two-way communication radio channel D (FD ch) /
A format U transmission start is transmitted to the mobile radio station 4. As a result, the mobile radio station 4 establishes the reception synchronization between the two-party communication radio channel D (FD ch) / format U.

The radio base station 2 is a radio base station management station 1
When the two-way communication channel synchronization acquisition B is sent from
The start of transmission / reception of the two-way communication channel is transmitted to the mobile radio station 4. The mobile radio station 4 transmits to the mobile radio station 3 a start of two-party communication radio channel C (FCch) / format U transmission in response to the start of transmission and reception of the two-party communication channel. As a result, the mobile radio station 3 establishes a two-way communication radio channel C
(FC ch) / Format U reception synchronization is established.

Thereafter, the mobile radio stations 3 and 4 respectively open communication channels, and a direct communication is performed between the mobile radio stations 3 and 4. The mobile radio station 3 transmits a start of two-party communication to the radio base station 2, and the radio base station 2 transmits the start of the two-party communication to the radio base station management station 1. After transmitting the start of the two-party communication, the radio base station 2 transmits a communication channel release notification to the mobile radio stations 3 and 4. The mobile radio stations 3 and 4 close the communication channel for the radio base station 2 in response to the communication channel release notification (see FIG. 13).

When the direct communication with the mobile radio station 4 is completed (step S30 in FIG. 10), the mobile radio station 3 notifies the radio base station management station 1 that the direct communication has been completed (FIG. 10). 10 Step S32), the transmission channel is released and the direct call mode transceiver 32 is stopped (FIG. 10 Step S33). At this time, the mobile radio station 4 also releases the transmission channel and stops the direct call mode transceiver 42.

The radio base station management station 1 does not receive a notification during the direct call from the mobile radio station 3 for a fixed time (step S1 in FIG. 8).
2, S14), when it is determined that the call is disconnected (step S15 in FIG. 8) or when the mobile radio station 3 is notified of the end of the call directly (step S13 in FIG. 8), the mobile radio stations 3, 4
A call termination process is performed (step S16 in FIG. 8).

That is, when the mobile radio station 3 goes on-hook, it transmits a preliminary call termination notification to the mobile radio station 4. The mobile radio station 4 stops the transmission / reception of the communication channel / format U between the two parties, and transmits a preliminary call termination notification reception to the mobile radio station 3. When receiving the preliminary call termination notification reception, the mobile radio station 3 stops the transmission / reception of the two-way communication channel / format U, and transmits a two-party communication end notification to the radio base station 2 to notify the network. Upon receiving the two-party communication end notification, the wireless base station 2 transmits a two-party communication end notification A to the wireless base station management station 1.

When the two-way communication channel release notices A and B are sent from the wireless base station management station 1, the radio base station 2 transmits the two-way communication channel release notice to the mobile radio stations 3 and 4. The mobile radio stations 3 and 4 release the two-way communication channel in response to the two-way communication channel release notification. Mobile radio station 3
After releasing the two-way communication channel, transmits a two-way communication channel release confirmation to the wireless base station 2, and the wireless base station 2 transmits a two-way communication channel release confirmation A to the wireless base station management station 1. (See FIG. 14).

In the above-described processing operation, the interface in the radio section is performed on the downlink signal from the radio base station 2 to each of the mobile radio stations 3 and 4 in the radio channel A and format D. From radio base station 2
It is assumed that the uplink signal to be transmitted is transmitted in radio channel B and format U.

In the direct communication mode transceivers 32 and 42 between the mobile radio stations 3 and 4, a signal from the mobile radio station 3 to the mobile radio station 4 has a radio channel D and a format U. A signal from the opposing mobile radio station 4 to the mobile radio station 3 has a radio channel C and a format U. The mobile radio station 3 also multiplexes and transmits the radio channel B and the format U to the radio base station 2 to notify the radio base station 2 that a call is in progress. The notification during the direct call is not demodulated by the mobile radio station 4.

FIG. 15 is a sequence chart showing a procedure when a call is interrupted in the mobile communication system according to one embodiment of the present invention. Referring to FIG. 15, a procedure when a call is interrupted in the mobile communication system according to one embodiment of the present invention will be described.

The mobile radio station 3 performs a resynchronization operation and transmits a two-party call interruption to the radio base station 2 when the reception synchronization is lost during a call with the mobile radio station 4, and the radio base station 2 Transmits the end of the two-way call to the wireless base station management station 1. The radio base station management station 1 confirms the end of the two-party call,
The mobile radio stations 3 and 4 are registered in the normal standby mode. The mobile radio station 3 sends a line disconnection notification to the mobile radio station 4 after notifying the interruption of the two-party call. The mobile radio station 4 blocks the direct call mode transceiver 42.

FIG. 16 is a sequence chart showing a procedure when the electric field drops in the mobile communication system according to one embodiment of the present invention. Referring to FIG. 16, a procedure when the electric field is reduced in the mobile communication system according to one embodiment of the present invention will be described.

When a decrease in the received electric field occurs during a call with the mobile radio station 4, the mobile radio station 3 prepares for network reconnection and transmits a notification of the electric field reduction to the mobile radio station 4. The mobile station 4 starts preparing for network reconnection.

Thereafter, the mobile radio stations 3 and 4 respectively transmit return communication channel requests to the radio base station 2, and the radio base station 2 transmits those return communication channel requests A and B to the radio base station management station 1. I do.

When the corresponding communication channel notifications A and B are sent from the radio base station management station 1, the radio base station 2 transmits the communication channel notifications to the mobile radio stations 3 and 4, respectively. In response to this, the mobile radio stations 3 and 4 set communication channels and establish reception synchronization.

When the setting of the communication channel / establishment of the reception synchronization is completed, the mobile radio stations 3 and 4 respectively transmit radio information notifications to the radio base station 2, and the radio base station 2 transmits the radio information notifications A and B to the radio base stations. It is transmitted to the station management station 1.

When the connections A and B are sent from the radio base station management station 1, the radio base station 2 reconnects the mobile radio stations 3 and 4.
Respectively. In response to this, the mobile radio stations 3 and 4 perform communication channel switching / two-party call disconnection, respectively, and transmit a reconnection confirmation notice to the radio base station 2. , B to the radio base station management station 1.

FIG. 17 is a diagram showing a format example of a three-party call according to another embodiment of the present invention. FIG.
FIG. 17 shows an example of a normal wireless format of a user call.
(B) shows an example of a time-division format of a three-party call,
FIG. 17C shows another example of the time-division format of a three-party call. A three-party call according to another embodiment of the present invention will be described with reference to FIGS. 17 (a) to 17 (c). The three-party call indicates that three or more mobile radio stations perform direct communication (call) between the mobile radio stations.

In the connection procedure of the three-party call, a simultaneous call group by the network and a plurality of mobile radio stations is registered in advance, and each mobile radio station is connected via the network at first, and the direct communication (call) is sequentially performed. Transition. The communication channel is set to a dedicated channel to avoid interference with the public line or increase in traffic.

Each mobile radio station shares a transmission channel and a reception channel, and can perform apparently simultaneous calls by time-division connection based on the ratio of persons in a predetermined radio frame. A mobile radio station is provided with time-division connection radio equipment in addition to ordinary radio equipment, and establishes group communication (call) at the timing of notification from the network side.

The prerequisites are (1) a distance where there is no risk of receiving deterioration due to direct communication, (2) a contract with the network side, and (3) radio equipment adapted to the service. There are (4) a synchronous system including a network, and (5) line design to reduce the time division so that the chip clock does not lose synchronization.

Each mobile radio station is a signal from a radio base station,
MS-A, MS-B, MS-C, MS while performing synchronization using the same chip code by reset start
-A,... [See FIG. 17 (b)]. The receiving side also demodulates the time-division signal while synchronizing the code and the clock, and converts it into an audio signal. If synchronization cannot be obtained between mobile radio stations, the radio format is changed. Note that MS-A, MS-B, and MS-C indicate each mobile radio station.

Also, the transmission time of each mobile radio station within a unit frame time is short, and a large number is allocated. Thus, the fluctuation of the clock can be kept low. further,
The format is changed without changing the assigned time of each mobile radio station within the unit frame time. A preamble for clock recovery, phase synchronization, and the like is added to the beginning of each time slot, that is, the preamble, MS-A, preamble, MS-B, preamble, and MS-C are configured [FIG. (C), the information that can be transmitted is reduced, but demodulation can be performed in a short time in each time slot.

In addition to the above configuration, when communication between mobile radio stations includes not only voice but also packet communication, 2
When exchanging large amounts of data at high speed between users, connecting to the network increases the load on the network at once,
The communication capacity with the other party may be low. So 2
There is a one-stone method in which two-way communication is used to reduce the load on the network and obtain a desired communication capacity.

For example, when the mobile radio station is moving away from the network area, if a sufficient receiving electric field cannot be obtained to maintain a clear voice, which is a condition for two-party communication during a call. Then, a procedure for returning to the network and continuing the call is entered, and the two-party communication cannot be continued.

In the case of packet communication, synchronization is not required unlike voice, so if the user returns from the area within a certain time and recovers within a certain period of time, even if the wireless connection synchronization is once lost, it can be recovered immediately. In packet communication, data can be transmitted by retransmission or the like.

In other words, when the normal network connection shifts to two-party communication and further shifts to data (packet) communication, data communication can be performed at a high speed in a large amount within the wireless connection synchronization protection time. The connection distance between the two parties can be longer than that during voice communication.

Further, a method in which the procedure for shifting from network connection to communication between two mobile radio stations between two parties is led by the network may be considered. The network sends broadcast information on the downlink through the wireless base station. As one of the broadcast information, two-way communication between mobile wireless stations is possible in this wireless base station area.

Each mobile radio station transmits an uplink to the radio base station at the time of location registration or outgoing / incoming call. This uplink signal also includes the unique information of the mobile radio station, and if the mobile radio station has a two-party communication function, it registers with the network. When communication between mobile radio stations within the same radio base station starts with a call connection managed on the network side, the unique information is checked, and if both parties have a two-party communication function and satisfy various conditions, By automatically starting the two-party communication procedure, the load on the network can be reduced. The location of the mobile radio station may be searched by a method of receiving information calculated by the mobile radio station, or may be independently searched by a plurality of radio base stations using the reception electric field, arrival delay time, and the like.

There are two types of mobile radio stations: communication while moving (walking / transportation means) and communication after moving without moving (mobile fixed station). In the above-described embodiment, the position of the mobile radio station is searched, and it is determined whether or not two-party communication is possible based on the unique information of the mobile radio station. I have. This is because the mobile radio station that wants to communicate does not know where it is and is moving.

When the user moves to a certain place for communication and performs communication from a fixed point without moving from there, the radio wave transmission position is already known, and the position does not change because he does not move.
Under such conditions, when connection to the communication partner is established by connecting to the network, the communication is immediately shifted to two-party communication. This is because complicated procedures such as position search, reception electric field strength investigation, distance calculation between mobile radio stations, and the like are simplified, and the two-party communication is quickly shifted to.

Normally, the connection procedure first searches the network for the location of the mobile radio station, specifies the radio base station area, and specifies the location of the mobile radio station using a plurality of radio base stations. Take the procedure.

However, in the above case, since the position of the mobile (fixed) radio station is known in advance, this procedure is not required, so that the procedure can be simplified. Since the unique information of the mobile radio station is also registered on the network side, two-party communication is possible when the other party is called, so that it is possible to shift without searching for information.

[0093]

As described above, according to the present invention, in a mobile communication system in which a plurality of mobile radio stations communicate via a radio base station under the control of a radio base station management station, The station determines whether direct communication is possible between a plurality of mobile radio stations without passing through a radio base station, and when it is determined that direct communication is possible, directs a direct call to each of the plurality of mobile radio stations. In addition, by activating a dedicated circuit for direct communication of each of a plurality of mobile wireless stations that perform direct communication in response to the instruction, it is possible to perform direct communication (call) between mobile wireless stations without passing through a network, This has the effect of reducing the load on the network and reducing the burden on the user.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a mobile communication system according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating communication between the radio base station and the mobile radio station in FIG. 1;

FIG. 3 is a diagram illustrating communication between the radio base station and the mobile radio station in FIG. 1;

FIG. 4 is a sequence chart showing a location registration procedure of the mobile communication system according to one embodiment of the present invention.

FIG. 5 is a sequence chart showing a normal call connection procedure of the mobile communication system according to one embodiment of the present invention.

FIG. 6 is a sequence chart showing a normal call connection procedure of the mobile communication system according to one embodiment of the present invention.

FIG. 7 is a flowchart illustrating a processing operation of the wireless base station in FIG. 1;

FIG. 8 is a flowchart showing a processing operation of the wireless base station of FIG. 1;

FIG. 9 is a flowchart showing a processing operation of the mobile radio station in FIG. 1;

FIG. 10 is a flowchart showing a processing operation of the mobile radio station of FIG. 1;

FIG. 11 is a sequence chart showing a two-party call connection procedure of the mobile communication system according to one embodiment of the present invention.

FIG. 12 is a sequence chart showing a two-party call connection procedure of the mobile communication system according to one embodiment of the present invention.

FIG. 13 is a sequence chart showing a two-party call connection procedure of the mobile communication system according to one embodiment of the present invention.

FIG. 14 is a sequence chart showing a two-party call connection procedure of the mobile communication system according to one embodiment of the present invention.

FIG. 15 is a sequence chart showing a procedure when a call is interrupted in the mobile communication system according to one embodiment of the present invention.

FIG. 16 is a sequence chart showing a procedure when the electric field is reduced in the mobile communication system according to one embodiment of the present invention.

FIG. 17 is a diagram showing a format example of a three-party call according to another embodiment of the present invention.

[Description of Signs] 1 Radio base station 3, 4 Mobile radio station 11 Communication control unit between mobile radio stations 12 Distance estimation unit between mobile radio stations 13 Electric field strength etc. estimation unit 21 Communication control unit 22 Direct communication mode transceiver

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04M 3/00 H04J 13/00 A F-term (Reference) 5K022 EE01 EE21 EE31 5K027 AA12 CC08 JJ03 5K047 BB01 BB05 CC01 DD01 HH11 5K051 AA05 CC07 FF11 HH01 HH15 5K067 AA29 AA41 BB02 CC08 CC10 DD57 EE02 EE10 EE16 EE25 GG01 HH21 JJ21 JJ53 JJ66

Claims (22)

[Claims] 1. A mobile communication system for performing communication between a plurality of mobile radio stations via a radio base station under the control of a radio base station management station, wherein the plurality of mobile radio stations do not pass through the radio base station. Determining means for determining whether or not direct communication between stations is possible, and communication control means for instructing each of the plurality of mobile radio stations each of the direct calls when the determining means determines that the direct communication is possible. In the radio base station management station, and each of the plurality of mobile radio stations has a dedicated circuit for direct communication for performing the direct communication in response to an instruction from the communication control means. . 2. The distance estimating means for estimating a distance between the plurality of mobile radio stations, and the electric field strength estimating means for estimating at least the electric field strength between each of the plurality of mobile radio stations. The mobile communication system according to claim 1, further comprising: 3. The distance estimating means searches a position of each of the plurality of mobile radio stations based on position registration by each of the plurality of mobile radio stations, and estimates a distance between the plurality of mobile radio stations. The mobile communication system according to claim 2, wherein the mobile communication system is configured as described above. 4. When the determining unit determines that the distance estimated by the distance estimating unit is a distance capable of maintaining communication quality between the plurality of mobile radio stations, the communication control unit determines that 4. The mobile communication system according to claim 2, wherein a call is instructed to each of said plurality of mobile radio stations. 5. Each of the plurality of mobile radio stations is configured to switch to the direct communication after activating the dedicated circuit for direct call and establishing radio synchronization and communication synchronization with a partner station of the direct communication. 5. The method according to claim 1, wherein:
The mobile communication system according to any one of the above. 6. The calling mobile radio station of the plurality of mobile radio stations notifies the radio base station of the start and end of the direct communication and the communication from start to end, respectively. The mobile communication system according to any one of claims 1 to 5, wherein the mobile communication system is configured. 7. The direct communication according to claim 1, wherein the direct communication is performed by time-dividing a preset radio frame between the plurality of mobile radio stations.
The mobile communication system according to any one of the above. 8. The mobile communication system according to claim 7, wherein transmission and reception are performed by adding a preamble to the beginning of each time slot of said radio frame. 9. The mobile communication system according to claim 1, wherein said direct communication between said plurality of mobile radio stations includes packet communication. 10. The direct communication is managed by using broadcast information notified from the radio base station management station to the plurality of mobile radio stations in a downlink through the radio base station. The mobile communication system according to any one of claims 1 to 9. 11. The apparatus according to claim 1, wherein the direct communication is performed immediately between the plurality of mobile radio stations when the positions of the plurality of mobile radio stations are fixed.
0. The mobile communication system according to any one of 0. 12. A direct communication method of a mobile communication system for performing communication between a plurality of mobile radio stations via a radio base station under the control of a radio base station management station, wherein the direct communication method does not involve the radio base station. Determining whether direct communication is possible between a plurality of mobile radio stations; and instructing each of the plurality of mobile radio stations to perform the direct call when the direct communication is determined to be possible. A direct communication method, which is provided in a base station management station, and wherein each of the plurality of mobile radio stations has a step of activating a dedicated circuit for direct communication for performing the direct communication in response to an instruction from the communication control means. . 13. The step of determining whether or not direct communication is possible includes estimating a distance between the plurality of mobile wireless stations, and determining at least an electric field strength between each of the plurality of mobile wireless stations. The direct call method according to claim 12, further comprising the step of estimating. 14. The step of estimating the distance includes searching for a position of each of the plurality of mobile radio stations based on location registration by each of the plurality of mobile radio stations to determine a distance between the plurality of mobile radio stations. 14. The direct telephone call method according to claim 13, wherein the estimation is made. 15. When the determining means determines that the distance estimated in the step of estimating the distance is a distance capable of maintaining communication quality between the plurality of mobile radio stations,
2. The communication control unit according to claim 1, wherein the direct call is instructed to each of the plurality of mobile radio stations.
The direct call method according to claim 3 or 14. 16. The method according to claim 16, wherein each of the plurality of mobile radio stations activates the dedicated circuit for direct call and establishes radio synchronization and communication synchronization with a partner station of the direct communication, and then switches to the direct communication. The direct call method according to any one of claims 12 to 15, wherein: 17. The calling mobile radio station of the plurality of mobile radio stations notifies the radio base station of the start and end of the direct communication and the communication from the start to the end, respectively. The direct call method according to any one of claims 12 to 16, wherein: 18. The apparatus according to claim 12, wherein the direct communication is performed by time-sharing a preset radio frame between the plurality of mobile radio stations. Direct call method. 19. The direct communication method according to claim 18, wherein a transmission / reception is performed by adding a preamble to the beginning of each time slot of said radio frame. 20. The direct call method according to claim 12, wherein the direct communication between the plurality of mobile radio stations includes packet communication. 21. The direct communication is managed using broadcast information notified from the radio base station management station to the plurality of mobile radio stations on a downlink through the radio base station. The direct call method according to any one of claims 12 to 20. 22. The direct communication between the plurality of mobile radio stations when the positions of the plurality of mobile radio stations are fixed.
The direct call method according to any one of 1.