JP2578820B2 - Wireless communication system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a wireless communication system of a small zone system (cellular system) and a mobile terminal used in this system.

[Conventional technology]

2. Description of the Related Art A mobile communication system such as a mobile phone is divided into a plurality of small wireless zones in a wide service area, and a wireless base station is arranged in each zone to communicate with a mobile terminal in the zone. Method) is used. In the small zone system, the range in which a radio wave propagates is limited to the inside and around the zone. Therefore, the same frequency can be repeatedly used in the area, and effective use of frequency resources can be achieved. Also, the transmission power can be reduced. These effects increase as the zone radius decreases.

On the other hand, with the advancement of information in social life, the demand for mobile communication that can be anywhere and everywhere is increasing. In order to respond to such demands, a car telephone service has been started which can be detached from a car and used for carrying. A mobile phone service is about to start soon. These new services share car phone equipment.

[Problems to be solved by the invention]

However, when trying to provide a mobile phone service with the current car phone system, the transmission power of the mobile terminal is lower than that of the in-vehicle terminal due to power supply and antenna gain restrictions. You can only get services in the area.

Also, if the zone radius is reduced according to the transmission power of the mobile terminal, the speed of movement of the car is much faster than the size of the zone, so the probability that the mobile terminal will move to another zone during a call will increase. The number of switching times of the medium channel is greatly increased, resulting in deterioration of the communication quality and an increase in the processing amount of the system.

As described above, a problem arises when it is attempted to provide a service to both the in-vehicle terminal and the portable terminal having greatly different transmission powers and moving speeds by the same small zone method.

An object of the present invention is to provide a wireless communication system in which an in-vehicle terminal and a mobile terminal are integrated and a mobile terminal used for the wireless communication system, which solves this problem.

[Means for solving the problem]

The present invention relates to a wireless communication system for providing services to both in-vehicle and portable mobile terminals, wherein a service area is overlaid with an in-vehicle terminal wireless zone and a mobile terminal wireless zone, A wireless base station is arranged in each of the wireless zones, and the mobile terminal determines whether or not the mobile terminal is in use, whether it is on-board or mobile. The communication is performed by selecting one of the radio base stations arranged in the zone.

[Operation] In the present invention, the service area is overlaid with two types of wireless zones having different sizes (a wireless zone for an in-vehicle terminal and a wireless zone for a mobile terminal), and the service area is respectively covered by a wireless base station for an in-vehicle terminal and a mobile terminal. We have a wireless base station. Depending on the state of the mobile terminal, that is, whether it is in-vehicle or portable, the mobile terminal connects to the in-vehicle terminal wireless base station or the portable terminal wireless base station for communication.

In the case of an in-vehicle terminal provided in an automobile, the terminal is connected to a wireless base station for the in-vehicle terminal. An in-vehicle terminal uses an automobile battery as a power source and has a higher antenna gain than a portable terminal, so that the transmission power can be relatively large and can sufficiently cope with a large zone. In this way, even in the case of an in-vehicle terminal having a high moving speed, the probability of moving to another zone during a call is low, and an increase in the number of channel switching can be suppressed.

In the case of a portable terminal carried by a subscriber, it is connected to a wireless base station for portable terminals. The mobile terminal has severe restrictions on the power supply and the antenna as compared with the on-vehicle terminal, and cannot increase the transmission power so much. For this reason, by further reducing the zone, terminals with low transmission power are accommodated. By installing a large number of wireless base stations for mobile terminals as compared with the wireless base stations for in-vehicle terminals, a service area equivalent to that of the in-vehicle terminals can be secured.

In the case of an in-vehicle terminal that can be used as a portable terminal by removing it from the car, a switch is provided at the contact point with the car to detect the state of attachment / detachment to / from the car and control to switch the wireless base station to be connected according to the attachment / detachment state Should be performed.

The connection control of the wireless line is performed by a control channel. The assignment of the control channel may be a method common to the in-vehicle terminal and the portable terminal, or a method of separation. In the former, one control zone is constituted by a plurality of in-vehicle terminal wireless zones and a plurality of mobile terminal wireless zones. In this control zone, both the in-vehicle terminal and the mobile terminal use a common control channel. In this case, it is necessary for the base station to identify whether the uplink control signal is from an in-vehicle terminal or a mobile terminal. On the other hand, in the latter, different control channels are respectively assigned to a vehicle-mounted terminal control zone composed of a plurality of vehicle-mounted terminal wireless zones and a mobile terminal control zone composed of a plurality of portable terminal wireless zones.
That is, since the on-board terminal and the portable terminal in the same area use different control channels, it is not necessary for the base station to identify whether the uplink control signal is from the on-board terminal or the portable terminal. When considering the wireless communication system of the present invention as a development form from the existing car telephone system, the latter is promising because the existing system requires less change.

When the in-vehicle terminal and the portable terminal use different control channels, it is efficient to identify the state of the terminal and select the control channel used for calling when the terminal of the in-vehicle terminal which can be the portable terminal is called. A method of providing a subscriber memory for managing the state of the terminal and transmitting a registration signal from the terminal when changing from in-car to in-car or from in-car to in-car is considered.

It is also possible to substitute the management of the terminal state by location registration. For this purpose, it is only necessary to assign different area identification codes to the in-vehicle terminal control zone including a plurality of in-vehicle terminal wireless zones and the mobile terminal control zone including a plurality of mobile terminal wireless zones. In this way, for example, even if the geographical position is the same, when the terminal changes from the in-vehicle terminal to the mobile terminal, the operation of position registration is started because the area identification code also changes. This location registration operation is performed by the Institute of Electronics and Communication Engineers, a car phone (supervised by Morii Kuwahara).
The description on page 185 is well known to those skilled in the art and will not be described here. By thus rewriting the position information in the subscriber memory, the terminal status can be managed.

For in-vehicle terminals that can also be used as mobile terminals,
When the state changes, it is necessary to switch the control channel and send the registration signal. For this purpose, there is a method in which a switch for detecting the attachment / detachment state with respect to the moving body is provided, and when the attachment / detachment state changes, the control channel is switched and a registration signal is transmitted. When the terminal state management described above is substituted for the position registration, it is only necessary to switch the control channel when the attachment / detachment state changes, and the registration signal is transmitted as a position registration signal.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing an example of a zone configuration of a wireless communication system according to the present invention. The hierarchy below the control zone is shown, and the hierarchy higher than this is outside the scope of the present invention and will not be described.
The in-vehicle control zone 1 includes a plurality of in-vehicle wireless zones 2, and the in-vehicle wireless base station 3 wirelessly communicates with the in-vehicle terminal 4 in each in-vehicle wireless zone 2. The portable control zone 5 includes a plurality of portable wireless zones 6, and the portable wireless base station 7 wirelessly communicates with the portable terminals 8 in each portable wireless zone 6.

The in-vehicle wireless network control station 9 is assigned to the in-vehicle control zone 1, and all the in-vehicle wireless base stations 3 in the in-vehicle control zone 1 are connected to the control station 9 in a star shape by a wired line. . Similarly, the portable radio network controller 10 is assigned to the portable control zone 5, and the portable control zone 5
All of the portable radio base stations 7 are connected to the control station 10 by a wired line in a star shape. Further, each on-vehicle wireless network control station 9 and each portable network control station 10 form a star,
It is connected to the exchange 11 by a wired line. In the exchange 11 a subscriber memory 12 is located.

If different wireless channels (communication channel and control channel) are assigned to the in-vehicle terminal and the portable terminal, the systems below the in-vehicle radio network controller 9 can be used with almost no change in the existing car telephone system.

FIG. 2 is a diagram showing an example of a control zone construction method. The service area 21 is overlaid by an in-vehicle control zone 22 and a portable control zone 23, and the in-vehicle control zone 22 and the portable control zone 23 have different area identification codes # A01 to # A03 and # B01 to #B, respectively. B14 has been granted. Different area identification codes are assigned to the in-vehicle control zone and the portable terminal control zone in the same area.

The location registration is a control for receiving the area identification code of the location information signal when the incoming control channel is switched, and transmitting the location registration signal on the outgoing control channel when this code is different from the one received so far. . When the terminal moves and moves to the control zone, a position registration signal is naturally sent. However, if the control zone is configured as in the present invention, the state of the terminal changes from in-vehicle to mobile or from in-vehicle to in-vehicle. Since the area identification code changes even when the location changes, a location registration signal is transmitted. The subscriber memory of the exchange is rewritten by this location registration signal. If different area identification codes are assigned to the in-vehicle control zone and the portable control zone in this way, the state of the terminal can be managed at the same time as the management of the position information, thereby simplifying the system configuration.

FIG. 3 is a diagram showing an embodiment of the mobile terminal of the present invention.
The mobile terminal includes an in-vehicle fixed unit 30, a detachable unit 40, and an in-vehicle fixed unit 30.
And a coupling portion 50 for easily and detachably coupling the detachable portion 40. Through the coupling section 50, the vehicle-mounted fixing section 30
The transmission and reception of wireless signals and the supply of power are performed between the device and the detachable unit 40. With such a structure, it can be used as a portable terminal only by the attaching / detaching portion 40, or as a vehicle-mounted terminal by being combined with the vehicle-mounted fixing portion 30.

The in-vehicle fixing unit 30 includes an in-vehicle antenna 31, an amplification circuit 32, an in-vehicle power supply 36, a charger 34, and a power supply terminal 35. The amplification circuit 32 amplifies the reception signal from the vehicle-mounted antenna 31 and sends it to the attachment / detachment unit 40 via the coupling unit 50, and amplifies the transmission signal from the attachment / detachment unit 40 via the coupling unit 50 to amplify the transmission signal. Send from. The vehicle power supply 33 receives power from a vehicle battery through a power terminal 35 and supplies power to the amplifier circuit 32 and the charger 34. The charger 34 charges the built-in power source 47 of the attaching / detaching portion 40 through the joining portion 50 when the attaching / detaching portion 40 is joined.

The attachment / detachment section 40 includes a built-in antenna 41, a changeover switch 42,
Radio circuit 43, control circuit 44, telephone 45, detachment detection circuit 46,
And a built-in power supply 47. The changeover switch 42 is controlled by the attachment / detachment detection circuit 46, and the wireless circuit 43 is connected to the in-vehicle antenna 31 when the attachment / detachment unit 40 is coupled to the in-vehicle fixed unit 30, and is disconnected from the in-vehicle fixed unit 30. Is a switch connected to the built-in antenna 41. Radio circuit 43
Modulates the control signal from the control circuit 44 and the audio signal from the telephone 45 into a radio signal and sends it to the switch 42,
The wireless signal from the changeover switch 42 is demodulated and sent to the control circuit 44 and the telephone 45. The attachment / detachment detection circuit 46 detects the attachment / detachment state by a mechanical switch 51 provided in the coupling unit 50, and inputs the information to the changeover switch 42 and the control circuit 44. The control circuit 44 switches the frequency of the control channel and the communication channel of the wireless circuit 43 according to the signal from the attachment / detachment detection circuit 46, and sends out a state registration signal. The built-in power supply 47 supplies power to each circuit of the detachable unit 40.

〔The invention's effect〕

As described above, according to the present invention, it is possible to provide a wireless communication system combining a mobile phone and a mobile phone and a mobile terminal suitable for use in the wireless communication system.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing an example of a zone configuration of a wireless communication system according to the present invention, FIG. 2 is a diagram showing an example of a control zone configuration method, and FIG. It is a figure showing an example. 1,22: In-vehicle control zone 2: In-vehicle terminal wireless zone 3: In-vehicle terminal wireless base station 6: Portable terminal wireless zone 7: Portable terminal wireless base station 23: Portable terminal control Zone 44 Control circuit 46 Detachment detection circuit

Claims (3)

(57) [Claims] In a wireless communication system for providing services to both in-vehicle and portable mobile terminals, a service area is overlapped with a wireless zone for an in-vehicle terminal and a wireless zone for a mobile terminal. A wireless base station is placed in each of the terminal wireless zones, the usage status of the mobile terminal is detected by the state of the switch equipped on the mobile terminal, and if the detected usage status is in-vehicle, the mobile terminal The mobile terminal selects a wireless base station located in the wireless zone for in-vehicle terminals, performs communication by selecting a wireless base station located in the wireless zone for in-vehicle terminals, and selects a wireless base station located in the wireless zone for mobile terminals when the detected use state is a portable state. A wireless communication method characterized by performing communication. 2. The wireless communication system according to claim 1, wherein the in-vehicle terminal wireless base station and the mobile terminal wireless base station use control channels of different frequencies. . 3. The wireless communication system according to claim 1, wherein a plurality of said in-vehicle terminal wireless zones form a in-vehicle terminal control zone, and a plurality of said portable terminal wireless zones are used for a portable terminal. A wireless communication system comprising a control zone, wherein different zone identification codes are assigned to an in-vehicle terminal control zone and a mobile terminal control zone in the same area.