JPH0344219A - Mobile communication system and base station and mobile terminal equipment used for the system - Google Patents

Abstract

PURPOSE:To attain the battery saving with simple control without imposing a burden on a control channel by devising the system such that a base station sends a synchronizing signal at a prescribed time interval and a mobile terminal equipment receives the synchronizing signal to control a timing of turning on a power source of a receiver. CONSTITUTION:The system consists of a controller 70 controlling the connection, plural base stations 81, 82 connecting to the controller 70 and a portable terminal equipment 90. The base stations 81, 82 send a synchronizing signal at a prescribed time interval and the transmission timing of a call signal to the terminal equipment 90 has a rule to the transmission time of the synchronizing signal. Upon the receipt of the synchronizing signal, each terminal equipment 90 turns on its power source based on the rule to cause the reception state. Thus, both the synchronizing signal and a call signal are sent only once. Thus, the battery saving without imposing excess burden on a control channel is attained.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a mobile communication system in which a plurality of base stations share a control channel to control communication between mobile terminals, and a base station and mobile terminal used in the system. Regarding.

(Prior Art) In mobile communication systems, a battery saving method is usually used in which the mobile terminal is intermittently powered on to receive data in order to reduce power consumption when the mobile terminal is in standby mode. A typical battery saving method is a method in which a call signal is transmitted repeatedly as many times as the terminal is powered on. However, this method has the problem that the same control information is transmitted many times, which increases the traffic on the control channel.

As a method to solve this problem, the terminal transmits a synchronization probability request signal when the power is turned on, and then periodically turns on the power at fixed time intervals and receives the signal.The base station then powers on the terminal using the synchronization probability request signal. Patent application No. 16661/1986 describes a method for calling a terminal at that timing when you know the time.
1 is proposed. This method is effective when the number of terminals per base station is small, such as cordless telephones.

(Problem to be Solved by the Invention) In a normal mobile communication system, in order to maintain a synchronized relationship between a terminal and a base station even when the terminal is not called, a synchronization system that allows the terminal to receive periodically in addition to a paging signal is used. A signal needs to be transmitted from a base station.

Therefore, in the battery saving method described above, when the number of terminals per base station increases, it becomes necessary to constantly transmit a synchronization signal even when there is no call in order to maintain a synchronized relationship with all terminals. This is not a problem in cases where each control zone has an independent control channel and can be used freely, such as in a car phone system, but this is not a problem in cases where multiple base stations share the same control channel, such as in a premises system. In this case, there is a problem in that the traffic on the control channel increases, putting pressure on calls to other base stations.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the conventional battery saving method described above and to provide a battery saving method that does not put pressure on the control channel.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the mobile communication system of the present invention provides a mobile communication system in which a plurality of base stations share a control channel to control communication between mobile terminals. The station transmits a synchronization signal that notifies the mobile terminal of the transmission timing of a paging signal that is intermittently transmitted on the control channel at a certain time interval, and the mobile terminal receives the synchronization signal and transmits a synchronization signal to the receiver. Controls the timing of power-on.

(Function) In order to realize battery saving by a method in which multiple base stations share the same control channel, and to prevent the amount of traffic on the control channel from increasing unnecessarily, in the present invention, the terminal is connected to the base station. A method is used to save battery by synchronizing with the synchronization signal from. In other words, the base station transmits a synchronization signal at regular time intervals, and the timing of transmitting the paging signal to the terminal follows a certain rule based on the transmission time of the synchronization signal. When each terminal receives the synchronization signal, it turns on the power and enters the receiving state based on the rules. In this way, both the synchronization signal and the calling signal need to be transmitted once.

On the other hand, when a terminal moves and moves to another base station's zone, the problem of a difference between the power-on timing and the synchronization signal transmission timing can be solved if the terminal becomes weaker or unable to receive the synchronization signal. Control is performed to find a synchronization signal by continuously receiving signals for a certain period of time.If a new base station with a strong synchronization signal is found, you can synchronize with that base station and save battery.At that time, location registration is performed. By transmitting signals, there is no need to call multiple base stations all at once. Furthermore, if the terminal has a plurality of threshold values and allows the terminal to resynchronize to a new base station with plenty of time before it becomes unable to receive a synchronization signal, it is possible to always synchronize to the base station with the best conditions.

Further, interference of synchronization signals can be avoided by instructing the control station to transmit synchronization signals so that multiple base stations do not transmit synchronization signals at the same time and cause interference.

(Example) Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a flowchart showing the operations of a base station and a terminal that constitute one embodiment of the present invention.

The base station resets an internal timer at a certain time based on an internally generated time or an external instruction, and at the same time sets an internal variable n to 1 and transmits a synchronization signal (step 111). After that, when the predetermined time To has elapsed, Stella 7112.113 checks whether a call request has been received each time.If there is a call request, it calls and changes the variable n.
is increased by 1 and the process is repeated until n=H (steps 114, 115, 116).

When this operation is repeated N times, the state is again waiting for the timing to reset the timer (step 110).
Here, it is not stated at what point the paging request arrives at the base station, but the major feature is that no matter what timing the paging request arrives, the paging signal will not be sent except when the timer is nTj. It has become. Therefore, when a terminal receives a synchronization signal, it can know at what timing a call signal will be transmitted or not, and can save battery accordingly.

On the terminal side, first, the receiver is powered on and receives a synchronization signal (steps 120, 121). Once the synchronization signal is received, it is possible to know at what timing a call signal will be received from then on. If possible, reset the internal timer, set the variable n to 1, and turn off the receiver (
Step 122), at this time, the timer is set so that time zero is not the time when the reception of the calling signal ends, but the time when the reception of the calling signal starts.

At time n To, turn on the power to the receiver and check whether there is a call signal to you.)
If there is a calling signal, the receiver goes into a talking state (steps 123 to 125); if no calling signal is received, the receiver is turned off (step 127), n is incremented, and the process waits for T0 time again.

When this operation is repeated N times (step 126), the state returns to the synchronization signal reception state. The synchronization signal may be transmitted with a certain deviation from the constant synchronization depending on the status of the base station, so
Keep the receiver in the receiving state continuously until the synchronization signal is received.In this way, if the terminal moves and moves to another zone, it will receive the synchronization signal of the other zone. Therefore, movement between zones can be detected.

This battery saving method for base stations and corresponding terminals eliminates the need for the base station to unnecessarily retransmit control signals over and over again, and also eliminates the need to transmit synchronization signals at different timings for each terminal. method can be realized.

FIG. 2 shows an example of the structure of a base station according to the present invention.

A synchronization signal transmission instruction and a call signal arrive at an input terminal 100 connected to an external control device. This signal is interpreted by the control section 40.

If the synchronization signal arrives, the control unit 40 sends a reset signal to the timer 20 and writes the synchronization signal into the buffer.On the other hand, the timer 20 resets its internal timer when the reset signal arrives. At the same time, the synchronization signal written in the buffer, which instructs the buffer 30 to transmit, is modulated by the modulator 10 and sent to the antenna 1.
Sent from 01. Thereafter, the timer 20 instructs to transmit the contents of the buffer at time intervals of To. After the NATO time has elapsed, the control unit 40 writes the synchronization instruction signal to the buffer 20 again in response to the synchronization instruction signal supplied from the outside and resets the timer 20. do.

If a paging signal arrives, it is written into the buffer and transmitted at the timing of the transmission instruction signal from the timer 20. Although this example has been explained in such a way that the synchronization instruction arrives from the outside, it is clear that it is also possible to generate it internally.

FIG. 3 shows an example of a terminal according to the present invention.

The battery saving operation of the present invention is performed by the power supply control unit 60.
This is realized by turning on and off the power to each circuit of the receiver, such as the demodulator 50, using a control signal from the receiver.

The signal received by antenna 102 is demodulated by demodulator 50 and output from terminal 103. The output of the demodulator 50 is input to a received signal determination circuit 51, which determines whether the received signal is a synchronization signal or a paging signal. If the received signal is a call signal, the power supply controller 60 puts the demodulator into a call mode and enters normal call processing. A detailed explanation of call processing will be omitted here.

When the received signal determining unit 51 notifies that the synchronization signal has been received, the power control unit 60 resets the first timer 61 and sends out a power cut signal. First timer 6
1 outputs a power-on signal and simultaneously resets the second timer 62 every time an integral multiple of the predetermined time T0 elapses.

The second timer 62 outputs a power-off signal to the demodulator 50 after a certain period of time has elapsed. However, the first timer 61
After the time N*T o has elapsed, a timer extension instruction is issued to the second timer 62, and the power is not turned off until the received signal determination section 51 receives a synchronization signal. At this time, the second timer 62 is set for a sufficiently long time so that the power-off signal is sent to the demodulator 50 after a period long enough to determine that the terminal has gone out of the service area. In this example, the power on/off signals are supplied to the demodulator 50 and the received signal determining section 51, but there is of course no problem even if there is another circuit that controls the power at the same time.

FIGS. 4(a) and 4(b) show the configuration and operation timing of an example of application to a local wireless system as another embodiment of the present invention.

Generally, in a local system, it is required to perform carrier sense and confirm that the channel is free before transmitting, so it is difficult to transmit signals at fixed time intervals. This section describes a battery saving method when synchronization signals cannot be transmitted at fixed time intervals due to carrier sense.

FIG. 4(a) shows the constituent countries of the system, and FIG. 4(b) shows the relationship between the timing of control signals transmitted from each device and the timing of starting the power supply of the terminal.

The system of this embodiment includes a control device 70 that controls connection;
A plurality of base stations 81, 82 . connected to the control device 70 . It is composed of a mobile terminal 90.

The control device 70 is connected to an external network through a terminal 103. The control device 70 transmits a synchronization instruction signal to the base station at certain time intervals.

At this time, in order to avoid multiple base stations transmitting synchronization signals at the same time, synchronization instructions are given to the new base stations at different timings.

When a base station receives a synchronization instruction signal, it transmits a synchronization signal.In normal in-premises wireless systems, each base station is required to perform carrier sense to check whether the line is open before transmitting a signal. transmits synchronous signals according to its rules.

In FIG. 4(b), the transmission timing of the synchronization signal at each base station may be delayed to some extent from the time when the synchronization instruction is received from the control device, because the line may not be connected. Each base station transmits a synchronization signal and then transmits a paging signal, if any, at regular time intervals. If carrier sense determines that the channel is not available when attempting to transmit, the process will wait until the next timing. The portion surrounded by the broken line in FIG. 4(b) is the timing at which the calling signal can be transmitted.

When a terminal receives a synchronization signal, it can know at what timing a calling signal will be sent after that, so if it turns on the power and receives the signal at that timing, it can be sure to receive a calling signal. can.

If the terminal moves and fails to receive the paging signal, the terminal continues to receive calls and waits to receive a synchronization signal. The terminal receives the synchronization signal, and the terminal performs battery saving in synchronization with the base station from which the synchronization signal was received.

FIG. 5 shows another configuration example of the base station according to the present invention. This example is used in a local system using carrier sense as explained in FIG. 4.

The input terminal 100 is connected to an external control device, from which a synchronization signal transmission instruction and a call signal arrive.

This signal is interpreted by the control section 40. If the synchronization signal arrives, the control unit 40 sends a reset signal to the timer 20' and writes the synchronization signal into the buffer. If it indicates that the buffer 30 is empty, it resets the internal timer and instructs the buffer 30 to transmit a synchronization signal.

The synchronization signal written in the buffer is modulated by the modulator 10 and transmitted from the antenna 10.1 via the hyperdrive 22.

If the output of the carrier sense circuit 21 indicates that the channel is not free, wait until the channel becomes free, and then reset the internal timer and send a synchronization signal to the buffer 30. Instruct.

Thereafter, the timer 20° instructs to transmit the contents of the buffer at time intervals To. This transmission instruction signal is sent to the gate circuit 2.
3, and is transmitted to the buffer 30 only when the output of the carrier sense circuit 21 is empty. Therefore,
If the channel is not free at that time, the transmission instruction is To
You will be forced to wait.

The control unit 40 writes the synchronization instruction signal into the buffer 30 again based on the synchronization instruction signal supplied from the external control device and resets the timer 20'. If a paging signal arrives, it is written into the buffer and transmitted at the timing of the transmission instruction signal from timer 20°. If the timer 20' attempts to issue a synchronization instruction to the buffer and the channel does not become free even after waiting for it to become free, it is naturally possible to time out after a certain period of time. In addition, the carrier sense circuit 21
has been described as always observing the channel state, but it is of course possible to control the observation so that it is performed only when necessary.

FIG. 6 shows another example of the configuration of the mobile terminal according to the present invention.

A signal received from antenna 102 is demodulated by demodulator 50 and output from terminal 103. At the same time, the demodulator 50
The output is input to a received signal determining circuit 51, which determines whether the received signal is a synchronization signal or a calling signal. If the received signal is a calling signal, the power supply control unit 60 sets the demodulator to a call mode and enters into a call process by energizing.

When the reception signal determination section 51 determines that the synchronization signal has been received, the power supply control section 60' resets an internal timer and sends out a power cutoff signal. Thereafter, the f&power supply control section 60' outputs a power-on signal every time a predetermined period of time Toc times N times elapses, and outputs a power-off signal when a predetermined period of time elapses. However, after N*76 hours have elapsed, the power is not turned off until the synchronization signal is received by the received signal determination section. This control is the same as the embodiment of FIG.

In this method, even if the terminal moves and gets closer to the base station in the pond, it continues to receive the synchronization signal from the original base station as long as it can receive the synchronization signal from the original base station without error. , signals from other base stations will be received only after the synchronization signal from the original base station can no longer be received. Therefore, if a call occurs while the user is moving, there is a high possibility that the call signal cannot be received.

In this example, in order to solve this problem, the received signal power is detected by the power detector 52, and the power comparison circuit 53 compares whether the received power of the synchronization signal has decreased. As a result of the comparison, if the received power of the synchronization signal has decreased by more than a certain value, it is determined that the terminal is moving, and the power supply control circuit is controlled to turn on the power of the receiver for a certain period of time and connect to other base stations. Receive a synchronization signal from If a synchronization signal stronger than that of the stored base station is received, power-on is controlled in synchronization with the synchronization signal of that base station. The power comparison circuit 53 is
This can be realized by a memory 55 that stores the power of the previous synchronization signal, and a comparator 54 that compares the contents of the memory 55 with the received power when the synchronization signal is received.

Although not described in this embodiment, when a mobile terminal changes synchronization to a different base station, if the terminal transmits a location registration signal, there is no need to transmit paging signals from multiple base stations. It is clear that the traffic on the control channel can be reduced.

(Effects of the Invention) As described in detail above, according to the present invention, there is an effect that battery saving can be performed with simple control without putting pressure on the control channel.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the operation of a base station and a terminal in an embodiment of the present invention, FIG. 2 is a configuration diagram showing a first example of a base station in the present invention, and FIG. A configuration diagram showing the first example, FIGS. 4(a) and 4(b) are a configuration diagram and an operation timing diagram of a mobile communication system in another embodiment of the present invention, and FIG. 5 is a diagram of a base station according to the present invention. FIG. 6 is a block diagram showing an example of the second example of the mobile terminal of the present invention.
This is an example of m factors. 10...Modulator, 20.20'...Timer, 22
...Hybrid, 30...Buffer, 40...
Control unit, 50... Demodulator, 51... Received signal determination unit, 52... Power detector, 53... Power comparison circuit, 54... Comparator, 55... Memory, 60.60
'...Power control unit, 61.62...Timer, 70
...Control device, 81°82...Base station, 90...
Mobile device.

Claims (6)

[Claims] (1) In a mobile communication system in which a plurality of base stations share a control channel to control communication between mobile terminals, the base station shifts the transmission timing of a paging signal that is intermittently transmitted on the control channel. A mobile communication system characterized in that a synchronization signal to notify a terminal is transmitted at a predetermined time interval, and the mobile terminal controls the timing of power-on of a receiver by receiving the synchronization signal. (2) A control unit that generates and outputs a reset signal using an external control signal or an internal clock, as well as generates and outputs a synchronization signal and a calling signal, and a control unit that is activated by the reset signal to reset an internal timer and instruct transmission. a timer that transmits a signal and outputs the transmission instruction signal when the value of the internal timer reaches a predetermined value; and a timer that stores the synchronization signal and the call signal from the control section; A base station for a mobile communication system, comprising: a buffer that receives and outputs the transmission instruction signal from the base station; and a modulator that modulates the output of the buffer. (3) A demodulator that demodulates the received signal, a received signal determining means that determines a synchronizing signal from the control signal demodulated by the demodulator, and a reset when the output of the received signal determining means determines that the synchronizing signal has been received. and a power supply control means for controlling the receiver to turn on/off the power to the receiver at predetermined intervals for a predetermined period of time, and to control the receiver to be powered on after the predetermined period is over. A mobile terminal for a mobile communication system characterized by comprising: (4) A control device that has means for sequentially instructing multiple base stations to transmit synchronization signals, and an internal timer is reset by the synchronization signal instruction signal from the control device, and the channel is empty by carrier sense. A plurality of base stations having a means for transmitting a synchronization signal after confirming the channel and transmitting a paging signal only at predetermined time intervals from then on when the channel is vacant, and synchronization from the base station. A mobile communication system comprising a plurality of mobile terminals that control the timing of power-on of a receiver by receiving signals. (5) Generate and output a reset signal based on a synchronization instruction signal from the control device, and generate and output a synchronization signal;
a control unit that outputs a calling signal when a calling signal is input from the outside; a carrier sense circuit that detects and outputs whether the control channel is vacant; and a carrier sense circuit that is activated by the reset signal to reset an internal timer;
a timer that outputs a synchronization signal transmission instruction signal if the output of the carrier sense circuit indicates that it is vacant, and outputs a paging signal transmission instruction signal when the timer value reaches a predetermined value; out of the transmission instruction signals from the timer, a gate circuit that outputs a calling signal transmission instruction signal only when the output of the carrier sense circuit is vacant; A base station for a mobile communication system, comprising: a buffer that receives and outputs a transmission instruction signal; and a modulator that modulates the output of the buffer. (6) a demodulator that demodulates a received signal, a received signal determining unit that determines a synchronization signal from the control signal demodulated by the demodulator, a power measuring unit that measures the power of the received signal, and the received signal determining unit power comparison means for detecting whether the received power of the synchronization signal detected by the means has decreased; and the output of the received signal determination means is reset when it is determined that the synchronization signal has been received; A power on/off signal for the receiver is sent at intervals, and after a certain period of time, the receiver is controlled to be powered on, and when the output of the power comparison means indicates a decrease in power, a signal is sent for a certain period of time. 1. A mobile terminal for a mobile communication system, comprising: power control means for controlling a receiver to be powered on continuously.