JP3169860B2 - Mobile communication system and communication range determination method thereof - 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 communication system and a communication area determination method therefor, and more particularly to a mobile communication system for transmitting data from a mobile station to a base station, and also when the electric field strength viewed from the base station is insufficient. The present invention relates to a communication range determination method capable of determining whether or not the mobile communication system is within a communication range.

[0002]

2. Description of the Related Art Generally, in a mobile communication system such as a portable telephone and a PHS, communication between a base station and a mobile station can be performed only when the mobile station is located within a service area of the base station. Therefore, the mobile station must be located within the service area and can communicate (hereinafter referred to as the communication area).
Must be notified to the user. In this case, in the conventional system, the mobile station determines whether or not the mobile station is within the communication range based on the electric field strength of the signal received from the base station, the data error rate, and the like, and displays the determination status on the display unit of the mobile station. Displayed and notified.

However, the transmission power between the base station and the mobile station,
Since there is a difference in antenna shape and the like, even if the mobile station can receive a signal from the base station, the base station does not always receive a signal from the mobile station. In some cases, communication was not possible even when the station determined to be within the service area.

In recent years, with the rapid spread of portable telephones, PHSs, and the like, there has been an increasing demand for higher reliability of mobile communication systems. In particular, there has been a situation where users recognize that they are within the communication range when waiting for an incoming call. Nevertheless, if the communication range determination is incorrect and a call loss occurs, there is an effect that the reliability of the entire mobile communication system is impaired.

[0005] FIG. 5 is a state transition diagram of a mobile station in the second edition of the standard (hereinafter referred to as PHS) of the conventional second generation cordless telephone system. The mobile station enters the base station search state 51 after the power is turned on, and searches for a base station within the service area. When a base station is found here, the state transits to the location registration state 52 next. In this position registration state 52, in order to register the own mobile station in the base station, as shown in the sequence diagram of the communication control signal at the time of position registration shown in FIG. An exchange takes place.

In this case, control signals are exchanged at the time of location registration, as shown in FIG. 6, when a request for establishing a link channel is first issued from a mobile station, the base station allocates a link channel and exchanges synchronization bursts. , Mobile station to SABM
(Set Asynchronous Ballanc
ed Mode) Control data is sent from the base station to the UA
(Unnumbered Acknowledge) is returned. Here, if necessary, the mobile station issues an MM (movement management) location registration request and an RT (radio management) definition request, the base station responds with an RT (radio management) definition, and the mobile station issues an RT function request. , The base station responds to the RT function request, and when the mobile station issues the RT secret key setting and the MM function request, the base station responds to the MM function request and the mobile station reports the MM location registration area. I do. Next, the base station
An M authentication request is sent, an MM authentication response is sent from the mobile station, and the base station sends an MM location registration acceptance. Here, when the connection is cut by DISC from the base station, the mobile station returns UA, the base station sends an RT wireless channel disconnection, and the mobile station completes the RT wireless channel disconnection.

[0007] When the location registration is completed in this way, the mobile station transits to the standby state 53. If the location registration fails, the process returns to the base station search state 51. This standby state 5
In 3, when the control signal from the base station is intermittently received and the incoming call signal to the own mobile station is received, the communication channel establishment state 54
Transition to. In this communication channel establishment state 54, FIG.
As shown in the sequence diagram of the communication control signal at the time of incoming call shown in
When a control signal indicated by an arrow is transmitted / received to / from the base station and a communication channel is successfully established, the state transits to a communicating state and communication becomes possible.

As shown in FIG. 7, when a mobile station receives an incoming call from a base station, the mobile station issues a link channel establishment request, and the base station transmits a link channel. It allocates link channels, exchanges synchronization bursts, sends SABM control data from the mobile station, and returns the UA from the base station. Next, the mobile station makes an RT incoming call response, the base station makes a CC (Call Control) call setup, and the mobile station returns a CC call setup acceptance. Here if necessary,
The mobile station issues an RT definition information request, the base station responds with the RT definition information, the mobile station issues an RT function request, the mobile station issues an RT function request response, and the mobile station issues an RT secret key setting and MM function. Request, the base station returns an MM function request response. Next, when an MM authentication request is sent from the base station,
The mobile station sends an MM authentication response, the base station calls the CC,
The mobile station responds with a CC, the base station confirms the CC response, and when a connection is made by DISC from the base station, the mobile station returns a UA and completes the sequence.

In the standby state 53, the mobile station compares the electric field strength at the time of receiving the control signal from the base station with a predetermined value to determine the communication area. To the user, and at the same time, inform the user that it is out of the communication range by display or the like. However, even if the signal from the base station can be received, but the base station cannot receive the transmission signal of the mobile station, the mobile station cannot determine that the mobile station is out of the communication range and continues to be in the standby state. become. In this case, an incoming call signal from the base station to the own mobile station is received, and a transition is made to the communication channel establishment state 54,
Transmission / reception is performed according to the communication control sequence at the time of incoming call shown in FIG. 6, and the mobile station recognizes that communication is impossible only after the base station fails to receive a control signal from the mobile station and fails to establish a communication channel. The mobile station transitions to the base station search state 51 due to the failure of the communication channel establishment and, at the same time, notifies the user of the fact that the mobile station is out of the communication range by display or the like.
In this case, the incoming call to the mobile station cannot be answered,
It will result in a call loss.

Next, the standby state will be described with reference to FIG. FIG. 8 is a timing chart showing an example of a control signal format in a standby state in a general PHS. Downlink control signals transmitted from the base station to the mobile station in the standby state include BCCH, SCCH, PCHn (n = 1 to
The same control signal is repeatedly transmitted every control signal frame period. The BCCH is called a broadcast channel and transfers information on a channel structure, system information, and the like. The SCCH is called a dedicated cell channel and transfers information on call connection. PCHn is a paging signal which is called a paging channel and transfers paging information and the like. The mobile stations PCH1 to PCH according to the uniquely allocated mobile station numbers.
6 may be received, and in FIG.
H1 is received. Therefore, the mobile station performs the call waiting operation by receiving PCH1 once every intermittent operation cycle T1,
As shown in the figure, it is common to turn off the power of the receiving unit and perform an intermittent operation for reducing power consumption except when receiving PCH1.

FIG. 9 is a timing chart showing the intermittent operation of the mobile station in a standby state. The mobile station transitions to the standby state after the completion of the location registration process, receives the PCH signal at the cycle T1, and repeats the operation of turning off the power supply during the time T2. In the communication area determination of the standby state, the PCH signal is normally received in the PCH signal reception process, and if the PCH signal reception electric field strength is equal to or more than a predetermined value, it is determined that the communication area is within the communication area.

FIGS. 10 and 11 are block diagrams showing a configuration of an example of the prior art described in Japanese Patent Application Laid-Open No. 3-291027. First, a portable device carried by a human among mobile stations will be described. In FIG. 10, the reception electric field strength of the signal from the base station received by the receiver 12 is indicated by a level detection circuit 1.
4 to detect. In the portable device, level sampling is performed by an instantaneous value detection circuit 61 in the portable device level processing circuit 60. The sampled output is subjected to an averaging process in the arithmetic processing circuit 62 in accordance with the mode switching control signal from the level detection control unit 65, to obtain level information to the portable device control unit. If there is a change in the size of the zone configuration of the base station service area, receive the mode information from the portable device control unit,
The level detection section 65 generates a mode switching control signal. Note that the fluctuation speed detection circuit 64, which has obtained the instantaneous value output from the level detection circuit 61, sets a reference value level that can follow the fluctuation of the reception level based on the value detected by the arithmetic processing circuit 62 to the reference value generation circuit 63. , And the number of times of instantaneous value fluctuation crossing the level reference value is counted to detect the speed of fluctuation of instantaneous fluctuation. The detected fluctuation speed is used by the level output control unit 65 to determine whether the portable device is being carried on a vehicle or being carried.

On the other hand, in the on-vehicle unit, as shown in FIG. 11, in the on-vehicle unit level processing count 70, the level detection control unit 73 performs the mode switching control based on the mode information from the on-vehicle unit control unit regarding the change of the zone configuration. I do. That is, the level signal from the level detection circuit 11 is sampled by the instantaneous value detection circuit 71, the arithmetic processing circuit 72 performs averaging processing according to the mode switching control signal from the level detection control section 73, and outputs the level signal to the onboard equipment control section. Information.
As described above, in the conventional example, the characteristics of the reception level fluctuation,
In particular, the communication range is determined by switching and detecting the detection time length of the received electric field strength using the difference in the fluctuation characteristics depending on the zone configuration and the moving speed.

[0014]

In the above-mentioned conventional mobile communication system, the communication area determination at the time of waiting for an incoming call is determined in one direction based on a control signal reception electric field strength from a base station, an error rate of reception data, and the like. Therefore, although the mobile station can receive the signal from the base station, the mobile station may erroneously determine that the mobile station is within the communication range even in a situation where the base station cannot receive the transmission signal from the mobile station. After the mobile station receives the incoming signal from the base station, it is necessary to transmit and receive a control signal to and from the base station for receiving the incoming call, and the base station receives the transmission signal from the mobile station. Otherwise, incoming calls cannot be accepted. Therefore, a call loss occurs even though the user recognizes that the user is within the communication range. Similarly, a call cannot be made from a mobile station.

In a situation where the mobile station can receive a signal from the base station but cannot receive a transmission signal from the mobile station, if the mobile station is properly determined to be out of communication range, another communicable base station is searched. Even if a call can be received by moving to the base station, there is also a problem that if the communication is erroneously determined to be within the communication range, a call waiting for the base station is continued, resulting in a call loss.

An object of the present invention is to solve these problems,
A mobile communication system and a communication range determination method that eliminates the occurrence of a call loss due to an erroneous determination because the base station determines whether or not the mobile phone is within the communication range when waiting for an incoming call. To provide.

[0017]

SUMMARY OF THE INVENTION An arrangement according to the present invention comprises at least one or more base stations and at least one or more mobile stations, wherein mobile stations communicate digital signals over a radio link between the stations. In the body communication system, the mobile station comprises:
A battery power supply unit for operating the mobile station, and a charge detection unit that detects a charged by which the state of the battery power supply unit, the mobile station is in standby mode incoming call signal from the base station, a predetermined distance in transmitting a signal indicating the communication area confirmation request to the base station, the base station, a communication area confirmation to the mobile station only when normal reception of the signal indicating the communication area confirmation request from said mobile station A signal indicating a response is transmitted, and only when the battery station is in a charged state and when the mobile station normally receives a signal indicating the communication range response from the base station, the mobile station is in a communication range. Is determined.

In the present invention, the base station includes a radio section for transmitting and receiving radio waves of a communication line and modulating / demodulating the radio waves, a codec section for encoding / decoding a modulation / demodulation signal of the radio section, and a receiving section for receiving / receiving signals from the radio section. A level detection circuit for detecting an electric field intensity, and a control unit for performing the communication range determination based on data input to the codec unit and electric field intensity information from the level detection circuit, the mobile station may include a communication line. A radio section for transmitting and receiving radio waves and modulating / demodulating the radio waves, a codec section for encoding / decoding a modulation / demodulation signal of the radio section, a level detection circuit for detecting an electric field strength of a signal received from the radio section, and the codec section And a control unit for performing the communication area determination based on data input to the device and electric field strength information from the level detection circuit.

[0019] In addition the present invention, the base station, speech processing of the speech coding and decoding a communication control unit, a coding and decoding signals of the codec unit that controls the communication by the output of the control unit for communicating within decision Unit, and a line connection unit that connects a sound signal to the sound processing unit to a line.The mobile station may include a communication control unit that controls communication based on an output of the control unit that performs the communication area determination. It may also include a voice processor for voice encoding and decoding a coding and decoding signals of the codec unit, and a sound output means for inputting and outputting audio to the audio processing unit.

The configuration of the communication range determination method according to the present invention includes a mobile communication system including at least one or more base stations and at least one or more mobile stations, and performing digital signal communication via a radio line between these stations. In the communication range determination method, the mobile station operates on battery power, a state in which the battery power is charged is detected, and the mobile station operates at predetermined intervals when the mobile station waits for an incoming call signal from the base station. Sends a signal indicating a communication range confirmation request to
The base station transmits a signal indicating the communication range acknowledgment to the mobile station only when normal reception of the signal indicating the communication area confirmation request from the mobile station, a state where the battery power source is charged The mobile station is determined to be in the communication range only when the mobile station receives the signal indicating the communication range response from the base station normally.

According to the configuration of the present invention, the mobile station transmits a communication area confirmation request signal to the base station at a predetermined time interval when waiting for an incoming call signal. By transmitting the area confirmation response signal and further normal reception of the communication area confirmation response signal by the mobile station, bidirectional communication confirmation can be performed, and the communication area is determined. Can be received, but the base station cannot receive the transmission signal from the mobile station,
It is possible to correctly determine that the base station is out of the communication range, search again for a communicable base station, and shift to the communication range. In the case where a communicable base station cannot be found, the problem of causing a call loss can be solved by notifying the user of the outside of the communication range and prompting the user to move to a place within the communication range. By eliminating such an incoming call loss, the reliability of the mobile communication system can be improved.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a basic configuration of one embodiment of the present invention, and includes a base station 20 and a mobile station 10. When the mobile station 10 waits for an incoming call signal from the base station, the control unit 15 transmits the predetermined interval (10 to 30).
In seconds), the communication area confirmation request signal is transferred to the CH (channel) codec unit 13 that sends the communication area confirmation request signal to the base station 20, and transmission is instructed. The CH codec unit 13 encodes the communication area confirmation request signal in accordance with the transmission timing and transfers the signal to the radio unit 12. The wireless unit 12
Modulates the communication range confirmation request signal into a high-frequency signal and transmits the signal to the antenna 1
1 to the base station 20 by radio.

The base station 20 receives the communication range confirmation request signal by the radio unit 22 via the antenna 21, demodulates the signal, and transfers it to the CH codec unit 23. The CH codec unit 23 decodes the communication area confirmation request signal and transfers it to the control unit 25. The control unit 25 confirms that there is no error in the communication range confirmation request signal, obtains the electric field strength detected when the radio unit 22 receives the communication range confirmation request signal from the level detection circuit 24, and obtains the predetermined electric field strength. When the above is confirmed, a process of outputting a communication area confirmation response to the mobile station 10 is performed.

In this communication area confirmation response output processing, first, the control section 25 transfers a communication area confirmation response signal to the CH codec section 23 and instructs the CH codec section 23 to transmit. Next, the CH codec unit 23 encodes the communication area acknowledgment signal in accordance with the transmission timing and transfers the signal to the wireless unit 22. This wireless unit 2
2 modulates the communication area acknowledgment signal and transmits it to the mobile station 10 wirelessly through the antenna 21.

The mobile station 10 receives the communication area confirmation response signal by the radio unit 12 through the antenna 11, demodulates it, and
Transfer to the H codec unit 13. The CH codec unit 13 decodes the communication area confirmation response signal and transfers it to the control unit 15. The control unit 15 confirms that there is no error in the communication area confirmation response signal, obtains the electric field strength detected when the wireless unit 12 receives the communication area confirmation response signal from the level detection circuit 14, and obtains the predetermined electric field strength. When it is confirmed that this is the case, it is determined that this is within the communication range. In addition,
If the communication area confirmation response signal cannot be received, if there is an error, or if the electric field strength is equal to or less than the predetermined value, it is determined that the communication area is out of the communication area.

[0026]

FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention, and shows a case where the present invention is applied to a PHS private system. In this PHS private system, a radio section of a conventional analog cordless telephone is digitized, and it is also called a digital cordless telephone using a π / 4 shift QPSK variation system and a time division multiple access system. Since the private base station has the same function as an analog cordless telephone, the private mobile station connects to the private base station using the PHS standard wireless system and talks on the general public line through the private base station. I have. For this reason, a unique charging system such as a PHS for public use called a simple portable telephone is not imposed, and a general public line charging system is provided.

In FIG. 2, a mobile station 10 is a private mobile station, a base station 20 is a private base station, and a mobile station 30 is a private mobile station taking into account a call waiting operation time. When the private mobile station 10 waits for an incoming call from the private base station 20,
The control unit 15 controls the private base station 2 at intervals of the intermittent operation cycle T3.
In order to transmit a communication range confirmation request signal to the communication code 0, the communication range confirmation request signal is transferred to the CH codec unit 13 and transmission is instructed. The intermittent operation period T3 is an integral multiple of the control signal frame period T1 described with reference to FIG.
Generally, T1 is used in about one second, so that T3 is 1
About 10 to about 10 seconds is appropriate. This CH codec part 1
3 encodes the communication area confirmation request signal in accordance with the transmission timing and transfers it to the radio unit 12. The radio unit 12 modulates the communication area confirmation request signal into a high-frequency signal and transmits the signal to the private base station 20 from the antenna 11 by radio.

[0028] The private base station 20 receives the communication range confirmation request signal by the radio unit 22 via the antenna 21, demodulates it, and transfers it to the CH codec unit 23. The CH codec unit 23 decodes the communication area confirmation request signal and transfers it to the control unit 25. The control unit 25 confirms that there is no error in the communication range confirmation request signal, obtains the electric field strength detected when the radio unit 22 receives the communication range confirmation request signal from the level detection circuit 24, and obtains the predetermined electric field strength. N
When it is confirmed that the number is 1 or more, a process of outputting a communication range confirmation response to the private mobile station 10 is performed. The value of the predetermined value N1 of the electric field strength is determined by the reception characteristics of the private base station 20, but is preferably about 10 to 40 dBμV, and since the deviation of the instantaneous power is large, it is sufficient to take an average value of an arbitrary time length. You need to be careful.

In the communication area confirmation response output processing, first, the control section 25 transfers the communication area confirmation response signal to the CH codec section 23 and instructs the CH codec section 23 to transmit. Next, the CH codec unit 23 encodes the communication area acknowledgment signal in accordance with the transmission timing and transfers the signal to the wireless unit 22. This wireless unit 2
2 modulates the communication area acknowledgment signal and transmits it to the private mobile station 10 wirelessly through the antenna 21.

The private mobile station 10 receives the communication area confirmation response signal by the radio unit 12 through the antenna 11, demodulates it, and transfers it to the CH codec unit 13. The CH codec unit 13 decodes the communication area confirmation response signal and transfers it to the control unit 15. The control unit 15 confirms that there is no error in the communication range confirmation response signal, and checks the level detection circuit 1
4, the electric field strength detected when the wireless unit 12 receives the communication area confirmation response signal is obtained, and when it is confirmed that the electric field strength is equal to or more than the predetermined value N2, it is determined that this is within the communication area. The value of the predetermined value N2 of the electric field strength is
Although it is determined by the reception characteristic of 0, it is desirable to be about 10 to 40 dBμV, as in the case of the private base station 20, and the deviation of the instantaneous power is large. There is. When it is determined that the private mobile station 10 is within the service area, the control unit 15 displays a message indicating the service area on the display unit 18 to allow the user to confirm the state. If the communication area confirmation response signal cannot be received, if there is an error, or if the electric field strength is less than the predetermined value N2, it is determined that the communication area is out of the communication area.

When a call is made using a general public line connected to the private base station 20, the private mobile station 10
The audio input from the microphone 19 is encoded by the audio processing unit 16, encoded by the CH codec unit 13, modulated by the radio unit 12, and transmitted wirelessly to the private base station 20 through the antenna 11. Further, the radio unit 12 demodulates a radio signal received from the private base station 20 through the antenna 11,
After being decoded by the CH codec unit 13, the audio is encoded by the audio processing unit 16 and converted into audio through the speaker 17. This series of communication control is managed by the control unit 15.

In the private base station 20, an audio signal from a general public line is input through a line connection unit 27, encoded by a speech processing unit 26, encoded by a CH codec unit 23, and modulated by a radio unit 22. The signal is transmitted wirelessly from the antenna 21 to the private mobile station 10. In addition, the private base station 20
Signal received through the antenna 21 from the
After demodulation at 2 and decoding at the CH codec unit 23, the audio is decoded at the audio processing unit 26 and connected to the general public line through the line connection unit 27 to make a call. The series of communication control is managed by the control unit 25.

[0033] Figure 3 shows a flow chart for executing the private mobile station communication range determination method of the embodiment of FIG. In FIG. 3, the control unit 15 described with reference to FIG.
It is executed at every predetermined interval T3 when receiving an incoming call signal from. First, in step 1, an area confirmation request message is transmitted to the private base station 20. Next, in step S2, a message is received from the private base station 20. If the message is received, the process proceeds to step S3. If the message is not received, the process proceeds to step S6. A timeout is determined for a predetermined time T4 (T4 <T3). For example, the process proceeds to step S7, where it is determined that the communication is out of the communication area.
If the timeout has not occurred in step S6, the process returns to step S2, and the message reception determination from the base station is performed again.

In step S3, it is confirmed whether the received message is an in-range confirmation response message. If the in-range confirmation response message has been normally received, the in-range determination is performed in step S4, the in-range display is performed in step S5, and the process is terminated. I do.
If it is determined in step S3 that the received message is not an area confirmation response message, the process returns to step S2, and the message reception determination process from the base station is performed again.

FIG. 4 shows a state transition diagram of the private mobile station of the embodiment of FIG . After the power is turned on, the private mobile station 10 enters the base station search state 41, and searches for the private base station 20 within the service area. In this search, the private base station 20
Is found, the state transits to the position registration state 42 next. In this position registration state 42, the self-service mobile station 10 is registered in the self-service base station 20. Therefore, as shown in FIG. Is performed with the base station. When the location registration is completed, the private mobile station 10 transitions to the standby state 43. If the location registration fails, the base station search state 41
Transition to. In the standby state 43, when the control signal from the private base station 20 is intermittently received and an incoming call signal to the private mobile station is received, the state transits to the communication channel probability state.
In the communication channel probability state 44, exchange of control signals indicated by arrows is performed with the private base station 20, as in the communication control sequence diagram at the time of incoming call described in FIG. If the communication channel is successfully established, the state transits to the communicating state and communication becomes possible.

In the standby state 43, the private mobile station 10 determines the communication range according to the process of the flowchart of FIG.
To the user, and at the same time, inform the user that it is out of the communication range by display or the like.

As described above, in a situation where the private mobile station 10 can receive a signal from the private base station 20 but cannot receive a transmission signal from the private mobile station 10. Can also be accurately determined to be out of the communication range, and the self-service base station 20 with which communication can be performed can be searched again to move to the communication range. In addition, when a communicable private base station cannot be found, the problem of causing a call loss can be solved by notifying the user of the outside of the communication range and prompting the user to move to a location within the communication range.

Next, the transmission timing of the communication area confirmation request signal and the communication area confirmation response signal will be described. The control signal format of the standby base station in the standby state is the same as the timing of FIG. 8 described in the conventional example, the communication range confirmation request signal is transmitted with information carried on the uplink SCCH, and the communication range confirmation response signal is The information is carried and transmitted using the extended call service type of the downlink PCH. When the transmission period T3 of the communication range confirmation request signal is set to five times the intermittent synchronization period T1 (T3 = 4 × T1), the SCCH timing 2.5 in FIG.
The transmission is performed from the private mobile station once every five times of the intermittent operation cycle T1 at a timing after ms. This communication range confirmation response signal is transmitted from the private base station at the PCH1 timing immediately after the reception of the communication range confirmation request signal.

When the communication range determination processing of this embodiment is performed, the power consumption increases because the number of transmission processing at the time of standby increases compared to a conventional mobile station generally using a battery as a power source. At present, the incoming call waiting operation time of the private mobile station is generally 400 to 600 hours. For example, when the communication area determination processing cycle T3 is set to the same cycle as the intermittent operation cycle T1 (T3 = T1), Incoming call waiting operation time is 3
It is reduced by a factor of 1 to 130-200 hours. But,
This secures enough time considering the usage of private mobile stations.

Next, one of the features of the present invention is the communication area.
The determination method will be described. In order to carry out this communication range determination method while securing the incoming call waiting operation time equivalent to that of the conventional mobile station, the system configuration of the mobile station 30 in consideration of the standby time shown in FIG. According to. This may be achieved by adding a charge detection circuit 40 to the system configuration of the private mobile station 10 as shown in FIG. The fact that the mobile station 30 for private use in FIG. 2 is installed and charged on a charging stand or the like,
When the detection is performed by the charging detection circuit 40, the control unit 35 performs the communication area determination process only while the charging detection circuit 40 detects that charging is being performed. In this case, the user can expect accurate communication range determination when the private mobile station 30 is mounted on the charging stand.

As another method, there is provided a switch for enabling the user to enable / disable the communication area determination processing, and to use accurate communication area determination control and control for increasing the call waiting operation time. By allowing the user to make a choice, the problem of prolonged use can be solved.

[0042]

As described above, according to the present invention, in the prior art, the determination of the communication area when waiting for an incoming call is made in one direction based on the strength of a control signal received from a base station, the error rate of received data, and the like. Therefore, although the mobile station can receive signals from the base station, the base station may not be able to receive a transmission signal from the mobile station. The base station that has received the communication area confirmation request signal to the mobile station transmits a communication area confirmation response signal to the mobile station, and the mobile station receives the communication area confirmation response signal normally, and the mobile station confirms bidirectional communication confirmation. Therefore, the communication area can be accurately determined, and it can be determined that the mobile phone is out of the communication area.

Further, even when the mobile station can receive the signal from the base station but cannot receive the transmission signal from the mobile station, if the mobile station is correctly determined to be out of the communication range,
Calling / incoming can be performed by searching for another communicable base station and transferring to the base station, so that calling / incoming can be reliably performed within the communication area. Can be improved in reliability.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a system configuration according to an embodiment of the present invention.

FIG. 3 is a flowchart illustrating a determination processing method according to the embodiment of FIG . 2 ;

FIG. 4 is a state transition diagram illustrating the operation of the embodiment of FIG . 2 ;

FIG. 5 is a state transition diagram illustrating the operation of a conventional mobile communication system.

FIG. 6 is a sequence diagram of a communication control signal at the time of conventional PHS location registration.

FIG. 7 is a sequence diagram of a communication control signal when a conventional PHS is received.

FIG. 8 is a timing chart for explaining a conventional control signal format in a communication standby state.

FIG. 9 is a timing chart showing a conventional intermittent operation of a mobile station in a standby state.

FIG. 10 is a block diagram showing a conventional level detection processing circuit for a portable device.

FIG. 11 is a block diagram showing a conventional on-vehicle level detection processing circuit.

[Explanation of symbols]

 10, 30 mobile station 11, 21, 31 antenna 12, 22, 32 radio unit (receiver) 13, 23, 33 CH codec unit 14, 24, 34 level detection circuit 15, 25, 35 control unit 16, 26, 36 Voice processing unit 17, 37 Speaker 18, 38 Display unit 19, 39 Microphone 20 Fixed station 27 Line connection unit 40 Charge detection circuit 41, 51 Base station search state 42, 52 Location registration state 43, 53 Standby state 44, 54 Communication Established state 60 Level processing circuit for portable device 61, 71 Instantaneous value detection circuit 62, 72 Operation processing circuit 63 Reference value generation circuit 64 Fluctuation speed detection circuit 65, 73 Level detection control unit 70 Level processing circuit for vehicle-mounted device

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04B ^7/ 24-7/26 H04Q ⁷ /04-7/38

Claims (6)

(57) [Claims] 1. A mobile communication system including at least one or more base stations and at least one or more mobile stations, in which digital signals are communicated by a radio channel between the stations, wherein the mobile station is connected to the mobile station. a battery power supply unit for operating the station, and a charge detection unit that detects a charged by which the state of the battery power supply unit, the mobile station is in standby mode incoming call signal from said base station, said at predetermined intervals transmits a signal indicating the communication area confirmation request to the base station, the base station, only the communication range acknowledgment to the mobile station when receiving normally a signal indicating the communication area confirmation request from said mobile station Signal indicating that the battery power unit is charging.
When time is and the mobile station of the condition being has normally received a signal indicating the communication range in response from the base station only, the mobile communication system, wherein the mobile station is determined to be in the service area . 2. The base station comprises: a radio unit for transmitting and receiving radio waves of the communication line and modulating / demodulating the radio waves; a codec unit for encoding / decoding a modulation / demodulation signal of the radio unit; 2. The mobile communication system according to claim 1, further comprising: a level detection circuit that detects an electric field intensity; and a control unit that determines the communication area based on data input to the codec unit and electric field intensity information from the level detection circuit. 3. The mobile station comprises: a radio unit for transmitting and receiving radio waves of the communication line and modulating and demodulating the radio waves; a codec unit for encoding / decoding a modulation / demodulation signal of the radio unit; 2. The mobile communication system according to claim 1, further comprising: a level detection circuit that detects an electric field intensity; and a control unit that determines the communication area based on data input to the codec unit and electric field intensity information from the level detection circuit. Wherein said base station, said communication control unit that controls the communication by the output of the control unit for communicating within determination and voice coding and decoding <br/> the coding and decoding signals of the codec unit 3. The mobile communication system according to claim 1, further comprising: a voice processing unit that performs the voice processing, and a line connection unit that connects a voice signal to the voice processing unit to a line. Wherein said mobile station, said communication control unit that controls the communication by the output of the control unit for communicating within determination and voice coding and decoding <br/> the coding and decoding signals of the codec unit 4. The mobile communication system according to claim 1, further comprising: a voice processing unit that performs voice processing and voice input / output means that inputs and outputs voice to and from the voice processing unit. 6. A communication area determination method for a mobile communication system including at least one or more base stations and at least one or more mobile stations, and performing digital signal communication through a wireless line between the stations. The station operates on battery power, a state where the battery power is charged is detected, and the mobile station sends a signal indicating a communication range confirmation request to the base station at predetermined intervals when waiting for an incoming call signal from the base station. transmitted, the base station transmits a signal indicating the communication range acknowledgment to the mobile station only when normal reception of the signal indicating the communication area confirmation request from the mobile station, the battery power is charged when and in case of being a state wherein the mobile station has successfully received the signal indicating the communication range in response from the base station only, characterized in that the mobile station is determined to be in the service area A communication area determination method for a mobile communication system.