JPH0511813B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vehicle-mounted wireless terminal in a wireless system that accommodates a large number of wireless terminals and has a large number of zones.

(Prior Art) In a cellular wireless communication system that accommodates a large number of wireless terminals and provides services to a wide area, it is extremely important to know where the terminal is located and to call the terminal. As a method for this, a method of calling all at once from the base station side has been commonly used. However, in the simultaneous paging method, as the service area expands, the number of zones to be called at once increases, the amount of traffic for paging increases, and this puts pressure on the system. On the other hand, it is possible to reduce call traffic by registering only the terminals that are turned on in the system and not making calls to unregistered terminals. Since wireless terminals generally operate on batteries, users are likely to turn off the power to the terminals when they are not in use. In this sense, this method is a powerful method. System C, Germany's new car phone system, employs this type of system. This method
IEEE periodical COMMUNICATIONS
From page 22 of MAGAZINE (published February 1986)
Detailed information is provided on page 29.

(Problem to be Solved by the Invention) However, in the conventional registration method described above, when the terminal is powered on, it can transmit a registration packet, but when the terminal is powered off, it cannot transmit anything, so the base station side has to turn off the power. cannot be recognized immediately. Therefore, the base station periodically transmits a transmission request signal for confirmation, and when there is no response, it is determined that the power has been turned off. However, this method has the disadvantage that the amount of traffic increases because the checks are performed periodically.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide an in-vehicle wireless terminal that allows a base station to reliably determine the power-on state of the terminal.

(Means for Solving the Problems) Means provided by the present invention to solve the above-mentioned problems is utilized in a wireless system that accommodates a large number of terminals, and is connected to the car's main power supply while the engine is running. An in-vehicle wireless terminal that uses a battery as a power supply source for a transceiver, a power switch that connects and connects a power line from the battery to the transceiver in conjunction with a car engine key, and a backup power source; a switch with a timer that switches the power supply source to the backup power source for a certain period of time when the user turns off the engine key; and a switch with a timer that is activated when the user turns off the engine key and uses the backup power source to shut off the power. The apparatus is characterized in that it includes at least a packet generating means for transmitting a packet.

(Function) If the power supply to the device stops immediately when the power switch is turned off, it is impossible to notify the base station of this fact. Therefore, in the present invention, even after the user turns off the power switch, the timer continues to supply power for a certain period of time, during which time a power-off packet is sent to the base station to notify the base station that the power will be turned off, and only after that Make sure to actually stop power supply.

Generally, in a vehicle-mounted wireless terminal, power is supplied to the terminal from the car's battery. In such a case, if the power supply is continued while the user is away from the car, the battery may overheat and the engine may become unable to start. Therefore, in the present invention, the power supply of the terminal is turned on and off in conjunction with the car's engine key, and the power supply is stopped when the user turns off the car key. In order to send a power-off packet, it is necessary to supply power for a certain period of time, so in the present invention, when the user turns off the engine key, the power source is switched to the backup power source, and after the power-off packet is sent, the power is switched back to the main power source. Power off the device. In this way, the base station can reliably recognize whether the terminal is powered on or off.

(Example) Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. Input terminal 1
A car key disconnection signal is input from 00, and an input terminal 101 is connected to a power line coming from the battery. When the user turns off the engine key of the car, a disconnection signal is input from the terminal 100. This disconnection signal causes the switch part 2 of the timer switch 20 to
1 is activated, and the power source of the transceiver 50 is switched from the battery power source from the terminal 101 to the standby power source 30. The timer 22 is activated by the disconnection signal and starts counting time. Furthermore, the packet generation circuit 40 generates a power-off packet based on the disconnection signal from the terminal 100 and sends it out from the antenna 102 via the transceiver 50. The time from the disconnection signal to the end of transmission of the power-off packet is known, and the timer 22 is set to a time slightly longer than that time, and the timer 22 times out when the set time elapses after the input of the disconnection signal. The switch 21 receives the timeout signal from the timer 22 and switches the power source of the transceiver 50 to the battery power source again.
However, at this time, since terminals a and b of the switch 10 are disconnected, the power to the transceiver 50 is turned off.

By doing this, the wireless terminal can notify the base station of the power-off operation, so the wireless base station can correctly recognize whether the terminal is powered on. Of course, in order for the base station to correctly recognize the status of the terminal, it also needs a function to send a registration packet when the power is turned on, and a function to re-register when the terminal moves and enters another zone. Since this is not a feature of the present invention and any method may be used, it is not described in this embodiment. In addition, the original functions of wireless terminals,
In other words, the function of transmitting and receiving voice and data is not a feature of the present invention, and any function may be used, so it is not described in this embodiment.

The timer switch 20 can be constructed in the same manner as a commercially available household timer. Additionally, the packet generation circuit 40 can be used with a microprocessor normally used for generating control signals. In fact, car phones and MCA radio devices have a built-in microprocessor for generating control signals, and by using this, a packet generation circuit can be realized without the need for additional hardware. The format of the power-off packet may be any format as long as it is agreed upon between the base station and the terminal.

The backup power supply 30 is used only when transmitting a power-off packet, so its capacity may be small. This can be a standalone battery, or it can be charged from the car's battery. Switch 10 may be either a mechanical switch or an electronic switch.

(Effects of the Invention) As described above in detail, according to the present invention, it is possible to provide a wireless terminal that allows an engine to correctly recognize a power-off state. Therefore, there is no need to periodically send a signal from the base station to check the status of the terminal, which simplifies control and reduces the amount of traffic. These terminals have a low operating rate per terminal, and the number of terminals is extremely large.
It is also particularly effective in mobile radio communication systems where the service area spans multiple zones.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram showing an embodiment of the present invention, in which reference numeral 10 indicates a power switch, reference numeral 2
0 indicates a switch with a timer, reference numeral 30 indicates a backup power supply, and reference numeral 40 indicates a packet generating means.

Claims (1)

[Claims] 1 Used in a wireless system that accommodates a large number of terminals, and when the engine is running, the car's battery, which is the main power source of the car, is used as the power supply source for the transmitter/receiver. a power switch that connects and disconnects a power line from the battery to the transmitter/receiver, a backup power source, and a switch with a timer that switches the power supply source to the backup power source for a certain period of time when the engine key is turned off by the user; , a packet generating means that is activated when a user turns off the engine key and transmits a power-off packet using the backup power source.