JP2873649B2 - Mobile device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile station used in a mobile communication system integrating a plurality of mobile communication modes.
In particular, the present invention relates to a technology for performing communication by selecting one of a plurality of mobile communication modes.

[0002]

2. Description of the Related Art There has been proposed an integrated mobile communication system in which a plurality of mobile communication modes having different radio interfaces are integrated. In this integrated mobile communication system, one mobile station can communicate in a plurality of mobile communication modes, for example, a cellular ground communication mode and a satellite communication mode.

In such an integrated mobile communication system, it is essential to detect the outside of the service area of each mobile communication mode. In the conventional mobile communication system, the detection of the outside of the service area is performed by the base station of the mobile device. This is performed when the average value of the reception level of the radio wave from the station for a certain period of time falls below a predetermined level. In general, in terrestrial mobile communication, radio waves from a base station in a mobile device undergo fading, so that the average value of the reception level fluctuates greatly. Therefore, even if it is determined that the vehicle is out of the service area, it may be determined that the vehicle has returned to the service area within a short period of time. At this time, if the location registration is performed every time the mobile station returns to the service area, the location registration traffic increases. Therefore, the conventional mobile communication system stores the latest location registration information and stores the same location registration area as before leaving the service area. When returning to the above, the amount of location registration traffic was suppressed by not performing location registration.

[0004]

In an integrated mobile communication system in which a plurality of mobile communication modes are integrated, when a mobile station switches between the mobile communication modes, a control channel of a mode to which the mobile station is switched is used. It is necessary to access the location registration memory and rewrite its contents. Therefore, if the switching between the mobile communication modes is performed by using the out-of-service area determination algorithm of the conventional mobile communication system, entering and exiting the service area of a certain mobile communication mode due to a change in the reception level of the mobile device due to fading is short. If it is repeated in time, there is a problem that the location registration traffic increases. This is called fluttering of mode switching.

[0005] It is an object of the present invention to provide a mobile station capable of reducing flutter of switching between modes in order to suppress the amount of location registration traffic and minimizing the communication unavailable time due to mode switching.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided a mobile station for performing communication by selecting a plurality of mobile communication modes having different radio interfaces, and a mode switching control means for controlling the switching of the mobile communication mode; A mobile communication mode reception level measuring unit; and a mode selection timer, wherein the mode switching control unit changes the reception level of the communication mode currently selected by the measurement of the reception level measuring unit to another communication mode. Means for activating the mode selection timer when the switching determination level falls below;
Means for controlling switching to another communication mode that can be switched by termination of the operation of the mode selection timer, and when the reception level of the currently selected communication mode exceeds the switching determination level while the mode selection timer is operating. Means for initializing a mode selection timer.

Preferably, the mode switching control means includes means for initializing the mode selection timer when an incoming call is received while the mode selection timer is operating.

The mode switching control means includes means for switching to another communication mode whose reception level is higher than the reception level of the currently selected communication mode when a call request is made while the mode selection timer is operating. Is preferred.

[0009] The mode switching control means, if the reception level of the mobile communication mode having a high selection priority exceeds the switching determination level from the currently selected communication mode to another communication mode, sets the currently selected communication mode. Means for selecting a communication mode with a high priority regardless of the reception level of the mode can be included.

Further, the plurality of mobile communication modes are a terrestrial mode and a satellite mode, and the mode switching control means determines that the short-term average value of the reception level in the terrestrial mode is lower than the determination level for switching from the terrestrial mode to the satellite mode. Means for activating a mode selection timer when the terrestrial mode is switched from the satellite mode to the terrestrial mode having a hysteresis with respect to the terrestrial mode to the satellite mode switching determination level. Means for switching from satellite mode to ground mode when the level is exceeded.

[0011]

When the mobile station is within the service area of the terrestrial mode, which is one mobile communication mode, the average value of the terrestrial wave reception level of the mobile station conforms to the operation sequence of the conventional terrestrial mode and the out-of-range determination level is obtained. It is determined that the service area is out of the service area when the value falls below the service area. After the out-of-service area determination, a mode selection timer for a predetermined time is started, and when it is determined that the mode selection timer has returned to the service area during operation, the mode selection timer is initialized and the mode returns to the ground mode. When an incoming call is received while the mode selection timer is operating, the mode selection timer is initialized and the mode is forcibly returned to the ground mode.

When a call request is issued from a terminal during operation of the mode selection timer, if the reception level of the satellite mode, which is another mobile communication mode, is equal to or higher than the out-of-range determination level,
Stop the mode selection timer and register the location in satellite mode. If it is not determined that the vehicle has returned to the terrestrial mode service area until the end of the mode selection timer, if the satellite mode reception level is equal to or higher than the out-of-service level, the location registration is performed in the satellite mode, and if the satellite mode reception level is equal to or less than the out-of-service determination level, The mode selection timer is restarted and the mode selection operation is repeated.

In the conventional mobile communication system, out of service area (switch from terrestrial mode to satellite mode)
Detection is based on the fact that the radio wave reception level from the base station in the mobile device falls below the out-of-service determination level, whereas the present invention uses the service area out-of-service detection mode selection timer, and uses the outgoing call information from the mobile device. Are switched together. The detection of entry into the service area (detection from the satellite mode to the terrestrial mode) is based on the fact that the average value of the reception level of radio waves from the base station in the mobile device exceeds the out-of-service determination level. The average value of the reception level of the measurement method of the mobile communication system exceeds the out-of-range determination level, and the average value of the reception level for a longer time exceeds the level higher than the out-of-range determination level by the amount of hysteresis to suppress further flutter. Is performed in combination.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a configuration of a mobile communication system in which a terrestrial mode and a satellite mode are integrated as an example of an integrated mobile communication system in which a mobile station according to an embodiment of the present invention is used.

In this integrated mobile communication system, the satellite mode service area 10 is set so as to include the terrestrial mode service area 11 formed by the terrestrial mode base station 8. The terrestrial mode base station 8, the terrestrial mode switch 7, the satellite mode base station, and the satellite mode switch 3 are connected to the mobile communication network 2 to enable communication between the terrestrial mode mobile station and the satellite mode mobile station. I have. The mobile communication network 2 is connected to the general telephone network 1 and can communicate with terminals of the general telephone network.

FIG. 3 is a block diagram showing an example of the configuration of a terrestrial / satellite dual mode mobile device 9 capable of performing mobile communication in both the terrestrial mode and the satellite mode according to the embodiment of the present invention. The radio system of this dual mode mobile unit has two systems, a terrestrial mode system and a satellite mode system.
5 allows communication in either mode.

That is, as a terrestrial mode system, a terrestrial radio control circuit 46, a terrestrial audio encoder 47 for encoding transmission audio, a terrestrial transmitter 49 for modulating and amplifying the encoded signal, A transmission / reception antenna 52, a transmission / reception duplexer 51, a terrestrial receiver 50 for receiving and amplifying and demodulating a signal from a base station, and a terrestrial audio decoder 48 for decoding the received signal into audio. Similarly, the satellite mode system includes a satellite audio decoder 53 and a satellite receiver 55.
Transmission / reception duplexer 58 and satellite transmission / reception antenna 59
, A satellite transmitter 56, a satellite voice encoder 54, and a satellite radio control circuit 57.

As a common circuit, the handset 41
A control signal changeover switch 42, a transmission sound changeover switch 43, a reception sound changeover switch 44,
A mode switching control circuit 45.

According to the present invention, the mode switching control circuit 4
5, and the mode switching control circuit 45
A mode selection timer is built in or connected to a mode selection timer, and mode switching is controlled by the operation of the mode selection timer. Although there is a reception level measuring circuit for detecting the reception level in the terrestrial mode and the satellite mode for mode switching, it is not shown because it is always provided in the mobile device.

Next, FIG. 2 shows an operation example of mode selection using the reception level in the mobile station in the terrestrial mode. FIG. 4 shows a case where the mobile station originates a call during the mode selection timer operation from the terrestrial mode to the satellite mode. FIG. 5 shows an operation example in the case where a call is received from the terrestrial mode during the operation of the mode selection timer from the terrestrial mode to the satellite mode, and FIG. Mode switching operation in the device will be described.

First, the mode switching operation of the mobile station will be described with reference to FIG.

The reception level short-term average value 22 and the reception level long-term average value 21 in FIG. 2 represent the reception level in the terrestrial mode received by the terrestrial receiver 50. This information is obtained by the processing, and is always notified to the mode switching control circuit 45.

While the mobile station is in the terrestrial mode service area 11, the mobile station is in the terrestrial mode operation 26, and the mode switching control circuit 45 monitors only the reception level short-term average value 22. As the mobile station approaches the edge of the terrestrial mode service area 11, the terrestrial mode reception level decreases, and at a certain time 29, the reception level short-term average value 22 falls below the deciding level 25 for switching from the terrestrial mode to the satellite mode. . This level is equal to the out-of-area determination level in the ground mode. At this time, the mode switching control circuit 45 sets the service area 11 of the mobile station in the ground mode.
Is determined to have gone out of the service area, the mode selection timer is started, and the mobile station shifts to the state of timer operation 27.

If the reception level short-term average value 22 exceeds the determination level 25 for switching from the terrestrial mode to the satellite mode at the time point 30 when the mode selection timer is operating,
The mode switching control circuit 45 determines that the mobile device has again entered the ground mode service area 11, stops the mode selection timer, and returns to the state of the ground mode operation 26.

When the reception level decreases again and, at time 31, the reception level short-term average value 22 falls below the determination level 25 for switching from the terrestrial mode to the satellite mode, the mode switching control circuit 45 switches the mobile station to the terrestrial mode service area. It is determined that the time has come out of 11, and the mode selection timer is started, and the mobile station shifts to the state of timer operation 27. If the reception level short-time average value 22 does not exceed the switching determination level 25 from the terrestrial mode to the satellite mode by the time 32 when the mode selection timer expires, the mode switching control circuit 45 stops the mode selection timer. Then, the state shifts to the state of the satellite mode operation 28.

At this time, the mode switching control circuit 45
It notifies the satellite radio control circuit 57 that the mobile station has entered the satellite mode service area 10. The satellite radio control circuit 57 performs location registration in the location registration memory 6 via the communication satellite 5, the satellite mode base station 4, and the satellite mode switch 3, using a satellite mode control channel. The mode switching control circuit 45 operates the control signal switching switch 42, the transmission voice switching system 43, and the reception voice switching switch 44, and
The radio control line and the communication line connected to the terrestrial radio control circuit 46, the terrestrial voice coder 47, and the terrestrial voice decoder 48 are transmitted from the satellite radio control circuit 57, the satellite voice coder 54, Switch to satellite audio decoder 53.

When the mobile station is in satellite mode operation 28,
The mode switching control circuit 45 monitors the reception level long-term average value 21 and the reception level short-time average value 22. When entering the terrestrial mode service area 11, the reception level in the terrestrial mode increases. The reception level short-term average value 22 exceeds the determination level 25 for switching from the terrestrial mode to the satellite mode, and the long-term reception level average value 21 suppresses the mode switching flicker from the determination level 25 for switching from the terrestrial mode to the satellite mode. The mode switching control circuit 45 determines that the mobile station has returned to the terrestrial mode service area 11 at a time point 33 when the switching level from the satellite mode to the terrestrial mode is exceeded by the hysteresis 24 higher than the hysteresis 24. Transition to the state.

At this time, the mode switching control circuit 45
Notifies the terrestrial radio control circuit 46 that the mobile device has entered the terrestrial mode service area 11. The terrestrial radio equipment control circuit 46 uses the terrestrial mode control channel to perform location registration in the location registration memory 6 via the terrestrial mode base station 8 and the terrestrial mode switch 7. The mode switching control circuit 45 includes a control signal switching switch 42,
Activate the transmission voice changeover switch 43 and the reception voice changeover switch 44 to connect the radio control line and the communication line connected to the handset 41 to the satellite radio control circuit 57, the satellite sound encoder 54, and the satellite sound decoder 53. From the terrestrial radio control circuit 46, the terrestrial audio encoder 47, and the terrestrial audio decoder 48.

Next, the operation when a call is made will be described with reference to FIG. FIG. 4 shows an operation when a call is made during the operation of the mode selection timer in the switching from the terrestrial mode to the satellite mode between the time 31 when the mode selection timer of FIG. It is shown. The mobile station in the terrestrial mode service area is in the terrestrial mode operation state 26. When the mobile station approaches the edge of the terrestrial mode service area, the reception level of the terrestrial mode decreases, and the mobile station is out of the service area at time 31. , And the process proceeds to the timer operation 27. At this time,
At a time point 61 before the time point 32 when the mode selection timer expires, when there is a call request from the terminal of the mobile station, the mode selection timer is stopped and the state shifts to the satellite mode operation 28 state.

FIG. 5 shows the operation when there is an incoming call during the mode selection timer operation.
This is the operation when there is an incoming call from the ground mode while the mode selection timer is operating. The mobile station in the terrestrial mode service area is in the terrestrial mode operation state 26. When the mobile station approaches the edge of the terrestrial mode service area, the reception level of the terrestrial mode is reduced. It is determined that the time has expired, and the process proceeds to the timer operation 27. At a time point 71 before the time point 32 when the operation of the mode selection timer ends, when there is an incoming call request from the terrestrial mode, the timer is stopped and the state is shifted to the terrestrial mode operation 26.

If there is no selectable communication mode even after the operation of the mode selection timer ends, the mode selection timer is restarted and the mode selection operation is repeated. Also,
For example, when the terrestrial mode has a higher priority than the satellite mode, and when the selected mobile communication mode is the satellite mode, the mobile communication mode having a higher selection priority than the selected mobile communication mode When the reception level exceeds the level that defines the end of the service area, control is also performed to select a high-priority terrestrial mode from the satellite mode that is the selected mobile communication mode.

In the above embodiment, it has been described that the satellite mode can always be used in a place outside the service area of the terrestrial mode. However, in the actual operation sequence, it is necessary to consider that there is a place where the satellite mode cannot be used due to shadowing by a tunnel, a building shadow, or the like.

[0034]

As described above, according to the present invention, the use of the mode selection timer suppresses the fluttering of the mode switching in which the mode is switched due to the shortfall of the reception level for a short time equal to or less than the timer time. The number of times of switching can be reduced. Furthermore, if a call is received from the ground mode while the mode selection timer is operating, the ground mode is selected, and if there is a call request from the terminal, the satellite mode is forcibly selected. Can be minimized.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of an integrated mobile communication system in which terrestrial mobile communication and satellite mobile communication are integrated.

FIG. 2 is a diagram showing an operation example of mode selection using a reception level in a mobile station in a terrestrial mode.

FIG. 3 is a block diagram showing a configuration example of a terrestrial / satellite dual mode mobile device.

FIG. 4 is a diagram showing an operation example when a call is issued from a terminal during operation of a mode selection timer from a terrestrial mode to a satellite mode.

FIG. 5 is a diagram showing an operation example when a call is received from the terrestrial mode during the operation of the mode selection timer from the terrestrial mode to the satellite mode.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 General telephone network 2 Mobile communication network 3 Satellite mode switch 4 Satellite mode base station 5 Communication satellite 6 Location registration memory 7 Terrestrial mode switch 8 Terrestrial mode base station 9 Terrestrial / satellite dual mode mobile station 10 Satellite mode service area 11 Terrestrial mode service Area 21 Long-term average of reception level 22 Short-term average of reception level 23 Judgment level for switching from satellite mode to terrestrial mode 24 Hysteresis for suppressing fluttering of mode switching 25 Judgment level for switching from terrestrial mode to satellite mode 26 terrestrial mode Operation 27 Timer operation 28 Satellite mode operation 29, 31 The short-term average value 22 of the reception level falls below the determination level 15 for switching from the terrestrial mode to the satellite mode,
The point at which the timer is started 30 The point at which the short-time average value of the reception level 22 exceeds the determination level 15 for switching from the terrestrial mode to the satellite mode 15 and the timer is stopped 32 The point at which the timer started at the point 34 is terminated and the mode is switched to the satellite mode 31 When the short-time average reception level 22 exceeds the judgment level 15 for switching from the terrestrial mode to the satellite mode and the long-term average reception level exceeds the judgment level 13 for switching from the satellite mode to the terrestrial mode 41 Handset 42 Control signal Changeover switch 43 Transmission audio changeover switch 44 Reception audio changeover switch 45 Mode switching control circuit 46 Terrestrial radio control circuit 47 Terrestrial audio encoder 48 Terrestrial audio decoder 49 Terrestrial transmitter 50 Terrestrial receiver 51 Terrestrial transmission and reception Vessel 52 ground transmitting / receiving antenna 53 Satellite audio decoder 54 Satellite audio encoder 55 Satellite receiver 56 Satellite transmitter 57 Satellite radio control circuit 58 Satellite transmission / reception duplexer 59 Satellite transmission / reception antenna 61 When a call request is notified from a terminal 62 When a call request is notified from the ground mode

Claims (5)

(57) [Claims] 1. A mobile device for performing communication by selecting a plurality of mobile communication modes having different wireless interfaces, comprising: mode switching control means for controlling switching of the mobile communication modes; and reception level measuring means for the plurality of mobile communication modes. And a mode selection timer, wherein the mode switching control means, when the reception level of the communication mode currently selected by the measurement of the reception level measurement means falls below the switching determination level for switching to another communication mode. Means for activating the mode selection timer; means for controlling switching to another communication mode that can be switched upon completion of the operation of the mode selection timer; and reception level of the communication mode currently selected while the mode selection timer is operating. Means for initializing the mode selection timer when the switching determination level is exceeded. The mobile device, characterized in that. 2. The mobile station according to claim 1, wherein the mode switching control means includes means for initializing the mode selection timer when an incoming call is received while the mode selection timer is operating. 3. The mode switching control means includes means for switching to another communication mode whose reception level is higher than the reception level of the currently selected communication mode when a call request is made while the mode selection timer is operating. Item 3. The mobile device according to item 1 or 2. 4. A mode switching control unit, wherein when a reception level of a mobile communication mode having a high selection priority exceeds a switching determination level from a currently selected communication mode to another communication mode, the currently selected communication mode is selected. 4. The mobile station according to claim 1, further comprising means for selecting a communication mode having a high priority regardless of a reception level of the mode. 5. The plurality of mobile communication modes are a terrestrial mode and a satellite mode, and the mode switching control means determines that the short-term average value of the reception level of the terrestrial mode is lower than the determination level for switching from the terrestrial mode to the satellite mode. Means for activating a mode selection timer when the terrestrial mode is switched from the satellite mode to the terrestrial mode having a hysteresis with respect to the deciding level for switching from the terrestrial mode to the satellite mode. Means for switching from satellite mode to terrestrial mode when the level is exceeded.
The mobile device according to any one of the above.