JP5125789B2 - Communication method and mobile station when line is busy in mobile radio communication system - Google Patents

Description

  The present invention relates to a communication method and a mobile station when a line is busy in a mobile radio communication system, and more particularly to a communication method and a mobile station when a line is busy in a mobile radio communication system that performs radio communication between a mobile station and a radio base station. .

  In a mobile radio communication system in which a radio base station performs radio communication with a mobile station located in the radio communication area, a standby mobile station includes a plurality of radio base stations (for example, base stations A, B, and C). Is located in the base station (referred to as base station A) having the highest received electric field strength among the received electric field strengths of the signals transmitted from the plurality of wireless base stations. sign up. In addition, when the mobile station comes to be in the wireless communication area of the base station having a higher received electric field strength than the base station A that is moving and registering the location, the mobile station performs a handoff for switching the line connection to the base station. Do.

  Here, when all the communication channels of the radio base station (base station A) whose location is registered are used when the mobile station originates (calls) for communication with the counterpart terminal, the base station A busy signal indicating “line busy” is transmitted from A to the originating mobile station. As a result, the mobile station fails to establish a line connection with the base station A, and until the base station A has a free communication channel and receives the busy recovery signal transmitted from the base station A, The line connection cannot be established, and communication with the partner terminal is awaited.

  Therefore, when the line is busy, the radio base station transmits a link establishment rejection signal in response to a call from the mobile station, and the mobile station that has received the link establishment rejection signal searches for the control channel of another base station. A communication processing method when a line is busy in which a link channel is established is known (see, for example, Patent Document 1). According to the communication processing method when the line is busy described in Patent Document 1, the call rate can be improved.

JP-A-9-163428

  In the communication processing method when the line is busy described in Patent Document 1, the mobile communication system as a premise is a communication system in which the wireless communication area of the wireless base station is a small area, such as PHS (Personal Handyphone System). Even if the registered wireless base station is busy and the mobile station stays in the wireless communication area of the wireless base station to which the handoff has been performed, the received electric field strength between the registered wireless base station and the wireless base station of the handoff has a large difference. Because there is no, it can communicate without problems.

  However, for example, in a mobile radio communication system of a large to medium area where the communication area of a radio base station such as 260 MHz digital administrative disaster prevention mobile radio and 260 MHz fire fighting SCPC (Single Channel Per Carrier) radio has a radius of 10 km, location registration is performed. When the received radio base station is busy, a handoff is performed as in the communication processing method when the line is busy as described in Patent Document 1, and a radio link is established with the handoff destination radio base station to communicate thereafter. Then, in the radio communication area of the handoff destination radio base station, the received electric field strength is low, and there is a high possibility that stable communication cannot be performed.

  The present invention has been made in view of the above points, and a line in a radio communication system capable of stable mobile communication by effectively using a communication channel of a position-registered radio base station that is no longer busy during communication. It is an object to provide a communication method and a mobile station when busy.

In order to achieve the above object, a communication method when the line is busy in the wireless communication system according to the first aspect of the present invention is such that the mobile station transmits for communication to the first wireless base station whose location is registered. 1, a second step in which the mobile station receives a busy signal from the first radio base station after transmission, and the mobile station that has received the busy signal has a plurality of radios around the first radio base station. A second radio base station that is a radio base station that receives a signal transmitted from a base station, measures its received electric field strength, and transmits a signal having the highest received electric field strength among a plurality of radio base stations A third step of handing off to the mobile station, a fourth step of setting a handoff control time period that defines a period during which handoff operation is prohibited after the third step, and the mobile station for communication with the second radio base station Outgoing, hand 5th step for determining whether or not the call was made within the period of the control period, and when it is determined by the fifth step that the call was made within the period of the handoff control period, via the second radio base station When the mobile station starts communication, the sixth step for releasing the handoff control time limit and the fifth step, when it is determined that the transmission is not performed within the period of the handoff control time limit, the handoff is performed when the handoff control time limit expires. The handoff operation is performed by releasing the control time limit in the seventh step and the handoff control time limit in the sixth step or the seventh step, and handoff is performed to the first radio base station having a free channel in the communication channel. And an eighth step of shifting to a state in which the mobile station performs communication via the first radio base station.

In order to achieve the above object, a mobile station according to a second aspect of the present invention includes a first transmission means for performing transmission for communication with a first radio base station that has registered a location, Receiving means for receiving a busy signal from one radio base station; receiving signals transmitted from a plurality of radio base stations around the first radio base station by receiving the busy signal; measured, the first handoff means for handing off to the second radio base station is a radio base station transmitting the highest signal reception field strength among a plurality of radio base stations, the handoff by the first handoff means A setting means for setting a handoff control time limit for determining a period during which handoff operation is prohibited later; a second transmission means for transmitting communication to the second radio base station; and a second radio base station. Second caller Determining means for determining whether or not the transmission is performed within the period of the handoff control time period, and when the determination means determines that the transmission is performed within the period of the handoff control time period, via the second radio base station A first canceling means for canceling the handoff control time limit when the mobile station starts communication, and a first canceling means for canceling the handoff control time limit when the determination means determines that the call is not made within the period of the handoff control time limit. And a second handoff means for performing handoff operation by releasing the handoff control time limit by the first or second release means and handing off to the first radio base station having a free channel in the communication channel. It is characterized by having.

  According to the present invention, in the case of line busy, communication is performed via a radio base station having the highest received electric field strength among radio base stations other than the radio base station that has become line busy. Since the handoff is automatically performed to the radio base station whose location of the highest received electric field strength that is no longer registered, stable communication can be continued thereafter through the radio base station of the highest received electric field strength.

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

  FIG. 1 is a system configuration diagram of an example of a mobile radio communication system to which a communication method and a mobile station are applied when a line is busy in a mobile radio communication system according to the present invention, and FIG. 2 is an example of a line control device in FIG. FIG. 3 is a block diagram of an example of a radio base station in FIG. 1, and FIG. 4 is a block diagram of an embodiment of a mobile station of the present invention.

In FIG. 1, the mobile radio communication system is composed of a control station 1 and m mobile stations 2 ₁ to 2 _m (m is a natural number of 2 or more), and the control station 1 and mobile stations 2 ₁ to 2 _m move. A communication system, which is a large-to-medium area mobile communication system that covers a communication area with a radius of about 10 km with one radio base station such as 260 MHz digital administrative disaster prevention mobile radio or 260 MHz fire fighting SCPC radio. In this mobile radio communication system, communication between the mobile stations 2 ₁ to 2 _m and the control station 1 and communication between mobile stations via a radio base station are performed.

The control station 1 includes a control table 11, a line control device 12, and n (n is a natural number of 2 or more) radio base stations 13 _{1 to} 13 _n . The control table 11 communicates with a designated mobile station among the mobile stations 2 ₁ to 2 _m via a line control device and a radio base station. The line control device 12 controls the entire wireless line. The wireless base stations 13 _{1 to} 13 _n perform wireless communication with a mobile station located in an area where the wireless communication can be performed among the mobile stations 2 ₁ to 2 _m . Each of the mobile stations 2 _{1 to} 2 _m performs radio communication only with the nearest one radio base station.

  As shown in the block diagram of FIG. 2, the line control device 12 includes a transmission / reception unit 121 that transmits and receives signals from the control table 1, a communication path switch 122 for forming a communication path necessary for mobile communication, and voice processing. Unit 123, audio signal transmitting / receiving unit 124 connected to audio processing unit 123, control unit 125 that controls the entire line control device 12, control signal processing unit 126, and control signal processing unit The control signal transmission / reception unit 127 is configured. Note that the control unit 125 also has a storage unit, and updates and stores the identification information of the radio base station and the mobile station whose positions are registered.

Further, the radio base stations 13 _{1 to} 13 _n in FIG. 1 have the same configuration, for example, the configuration shown in the block diagram of FIG. 3, a radio base station 13 (any one of 13 _{1 to} 13 _{n in} FIG. 1) includes an interface 131 that transmits and receives a voice signal and a control signal to and from the line control device 12, a signal processing unit 132, and a radio The unit 133, the control unit 134, and the transmission / reception antenna 135 are configured.

  The signal processing unit 132 communicates with the output audio signal of the interface 131 through the communication channel, performs signal processing for performing communication with the output control signal of the interface 131 through the control channel, and receives the received communication channel and control channel. The signal processing of the above signal is performed and the processing to output to the interface 131 is performed. The radio unit 133 performs radio communication using the SCPC method with the nearest mobile station via the transmission / reception antenna 135. This SCPC method is a method of performing communication by allocating one carrier wave per communication channel, and is particularly effective for voice communication. The control unit 134 is supplied with the control signal output from the interface 131 and is also supplied with the control signal in the received signal from the mobile station 2 to control the entire radio base station 13 in an integrated manner.

Further, the mobile stations 2 ₁ to 2 _m in FIG. 1 have the same configuration, for example, the configuration shown in the block diagram of FIG. 4, a mobile station 2 (any one of 2 ₁ to 2 _{m in} FIG. 1) includes a transmission / reception antenna 20, a control unit 21 that controls the mobile station 2 in an integrated manner, an input unit 22 such as a numeric keypad, and a program. And a storage unit 23 that stores telephone directory data and the like, a wireless unit 24 that wirelessly communicates with any of the nearest wireless base stations 13 _{1 to} 13 _n via the transmission / reception antenna 20, a signal processing unit 25, The voice processing unit 26, the voice input / output unit 27, the display driving unit 28, and the display unit 29 are provided.

  The signal processing unit 25 performs predetermined signal processing on the dial signal or character data from the control unit 21 or the transmission voice signal obtained by the voice input / output unit 27 from the voice processing unit 26, and sends the signal to the radio unit 24. Supply as a transmission signal. The signal processing unit 25 outputs character data and group communication information obtained by performing predetermined signal processing on the signal received by the radio unit 24 to the control unit 21, and also receives the received voice signal as a voice. This is supplied to the voice input / output unit 27 via the processing unit 26.

The voice input / output unit 27 includes a microphone that performs acoustic-electrical conversion on the transmitted voice signal, and a speaker that generates the voice of the received voice signal by performing electric-acoustic conversion. The voice processing unit 26 performs predetermined voice processing on the transmission voice signal from the microphone in the voice input / output unit 27 and supplies the signal to the signal processing unit 25, and the received voice signal from the signal processing unit 25 On the other hand, predetermined audio processing is performed and output to a speaker in the audio input / output unit 27. The display driving unit 28 performs predetermined known display processing on the display signal from the control unit 21 and causes the display unit 29 to display the display signal.
Indicates.

  Based on the program stored in the storage unit 23, the mobile station 2 configured as described above is freed by handing off to another radio base station when the radio base station called by the control unit 21 is busy. The communication channel is effectively used, and even if communication is being performed via another radio base station, handoff is performed to the radio base station whose location has been registered after a predetermined time so that communication via the radio base station can be performed. It is characterized in that it performs control.

Next, the operation of the present embodiment will be described with reference to the sequence diagram of FIG. Here, for convenience, among the mobile station ₂ 1 to 2 _m, for explaining the operation of the mobile station _{2 1} as an example. Periodically receiving a predetermined signal being transmitted the received field strength measured by the radio base station of the highest received field strength among the mobile station 2 ₁ from the radio base station 13 ₁ to 13 _n in the standby It is assumed that the location is registered in (this is 13a). This location registration information is stored in the line control device 12.

In this state, in order to communicate and control board 11, it is assumed that the mobile station 2 ₁ is sent to the radio base station 13a that the location registration (step S1 in FIG. 5). However, at this time, assuming that the communication channel of the radio base station 13a is busy all the busy signal indicating "line busy" is sent to the mobile station 2 ₁ from the radio base station 13a ( Step S2 in FIG. Accordingly, the mobile station 2 ₁ fails to line connection to the wireless base station 13a. Therefore, the mobile station 2 ₁ returns to standby, the received field strength is measured by receiving a predetermined signal which is periodically transmitted from the radio base station 13 ₁ to 13 _n, the radio base station therein Handoff is performed to a radio base station having the highest received electric field strength other than 13a (referred to as 13b) (step S4 in FIG. 5).

Subsequently, the mobile station 2 ₁ sets the timer of the voice communication time period that is broadcast by the control channel to "line busy during handoff control timed" (step S5 in FIG. 5), the duration of the line busy during handoff control timed Prohibits the handoff operation (step S6 in FIG. 5). Note that the line busy handoff control time limit is, for example, 3 minutes at a predetermined fixed time.

Subsequently, the mobile station 2 ₁ is the duration of the line busy during handoff control timing, in order to communicate and control board 11, and those originating in the radio base station 13b that handoff (step S7 in FIG. 5, in step S8 YES) The radio base station 13b supplies the above transmission information to the line control device 12, so that the control table 11 and the mobile station are connected with the communication channel corresponding to the speech path registered by the speech path switch 122 in the line control device 12. Communication with 2 ₁ is started (step S9 in FIG. 5).

Mobile station 2 ₁ by the communication releases the line busy during handoff control timed (step S10 in FIG. 5), the handoff operation prohibited canceling (step S11 in FIG. 5). As a result, when an empty channel is created in the communication channel of the radio base station 13a having the highest received electric field strength by the handoff operation during communication, handoff is performed to the radio base station 13a (step S12 in FIG. 5), communication and control board 11 via the base station 13a and the mobile station _{2 1} is continued (step S13 in FIG. 5).

As described above, in the present embodiment, when the line is busy, communication is started via the radio base station 13b having the second highest received electric field strength, and therefore communication on a stable radio line cannot be expected. However, in this embodiment, when a free channel is created in the communication channel of the radio base station 13a having the highest received electric field strength during the communication, the radio base station 13a is automatically handed off. the most stable communication between the highest reception field strength via the radio base station 13a and the control board 11 and the mobile station 2 ₁ can be continued.

The mobile station 2 ₁ after the expiration of the line busy during handoff control timing, when the outgoing to the communication with the control board 11 (NO in step S8 in FIG. 5) becomes a transmitter for the radio base station 13a, the radio base station 13a communication and control board 11 and the mobile station 2 ₁ through is started. Since the communication channel used by the radio base station 13a before the expiration of the line busy handoff control time limit is forcibly disconnected at the voice communication time limit, after the line busy handoff control time limit expires, the radio base station 13a This is because there is a high possibility that the communication channel is an empty channel. This reduces the possibility that the line will be busy and the call will fail.

In the above embodiment has been described communication between the control board 11 and the mobile station 2 _1, each equally applicable for communication between two mobile stations mutual via the nearest base station It is. The present invention can also be applied to a TDMA (Time Division Multiple Access) system other than the SCPC system.

1 is a system configuration diagram of an embodiment of a mobile radio communication system to which the present invention is applied. It is a block diagram of an example of the line control apparatus in FIG. FIG. 2 is a block diagram of an example of a radio base station in FIG. 1. It is a block diagram of one Embodiment of the mobile station of this invention. It is a sequence diagram for operation | movement description of one Embodiment of this invention.

Explanation of symbols

1 Control station 2 ₁ to 2 _m mobile station 11 controls stage 12 line control unit 13 ₁ to 13 _n radio base station 21,125,134 controller 23 storage unit 24,133 radio unit 25,132 signal processing unit 122 channel switch 123 Voice processing unit 126 Control signal processing unit 131 Interface

Claims (5)

A first step in which a mobile station makes a call for communication with a first radio base station that has registered a location;
A second step in which the mobile station receives a busy signal from the first radio base station after the transmission;
The mobile station that has received the busy signal receives signals transmitted from a plurality of radio base stations around the first radio base station, measures the received electric field strength, and the plurality of radio base stations A third step of handing off to a second radio base station that is a radio base station transmitting the signal having the highest received electric field strength,
A fourth step of setting a handoff control time period that defines a period during which handoff operation is prohibited after the third step;
A fifth step of determining whether or not the mobile station has made a call for communication to the second radio base station within the period of the handoff control time period;
When it is determined in the fifth step that the call is made within the period of the handoff control time period, the handoff control time period is set when the mobile station starts communication via the second radio base station. A sixth step to cancel,
A seventh step of canceling the handoff control time limit when the handoff control time limit expires when it is determined in the fifth step that the call is not made within the period of the handoff control time limit;
The handoff operation is performed by releasing the handoff control time limit in the sixth step or the seventh step , and handoff is performed to the first radio base station that has a free channel in the communication channel. A communication method when the line is busy in a mobile radio communication system, comprising: an eighth step of shifting to a state in which the mobile station performs communication via a station. A control station, a line control device, and a control station having a plurality of radio base stations and a plurality of mobile stations, the radio between the control station and the mobile station or between two mobile stations A communication method when a line is busy in a mobile radio communication system that performs communication via a base station,
Among the plurality of radio base stations in the control station, the mobile station makes a call for communication with the control table or another mobile station to the first radio base station whose location is registered. 1 step,
A second step of receiving a busy signal from the first radio base station after the transmission by the mobile station as a transmission source;
The mobile station that has received the busy signal receives a signal transmitted from a radio base station around the first radio base station among the plurality of radio base stations in the control station, and receives a received electric field thereof. A third step of measuring an intensity and handing off to a second radio base station which is a radio base station transmitting the signal having the highest received electric field strength among the neighboring radio base stations;
A fourth step of setting a handoff control time period that defines a period during which handoff operation is prohibited after the third step;
It is determined whether or not the mobile station has made an outgoing call for communication with the control base or another mobile station in the control station to the second radio base station within the period of the handoff control time limit. A fifth step;
When it is determined in the fifth step that the call is made within the period of the handoff control time period, the mobile station via the second radio base station can control the mobile station or another mobile station in the control station. A sixth step of canceling the handoff control time period when communication with is started;
A seventh step of canceling the handoff control time limit when the handoff control time limit expires when it is determined in the fifth step that the call is not made within the period of the handoff control time limit;
The handoff operation is performed by releasing the handoff control time limit in the sixth step or the seventh step , and handoff is performed to the first radio base station that has a free channel in the communication channel. A communication method when the line is busy in a mobile radio communication system, comprising: an eighth step of shifting to a state in which the mobile station performs communication via a station. The mobile radio communication system, 260MHz digital administrative emergency mobile radio communication system, or 260MHz fire SCPC method of communication when the line busy in a mobile radio communication system according to claim 1 or 2, wherein the a wireless communication system. A first transmitting means for performing outgoing for communication with respect to the first radio base station which location registration,
Receiving means for receiving a busy signal from the first radio base station after the transmission;
By receiving the busy signal, a signal transmitted from a plurality of radio base stations around the first radio base station is received and the received electric field strength is measured, and the reception of the plurality of radio base stations is performed. First handoff means for handing off to a second radio base station that is a radio base station transmitting a signal having the highest electric field strength;
Setting means for setting a handoff control time period that defines a period during which handoff operation is prohibited after the handoff by the first handoff means ;
Second transmission means for performing transmission for communication to the second radio base station;
A determination unit that determines whether or not the transmission by the second transmission unit is performed within the period of the handoff control time period to the second radio base station;
When it is determined by the determination means that the transmission is performed within the period of the handoff control time period, the handoff control time period is canceled when the mobile station starts communication via the second radio base station. First release means;
A second canceling unit for canceling the handoff control time period when the determination unit determines that the transmission has not been performed within the handoff control time period;
Second hand-off means for performing hand-off operation by releasing the hand-off control time limit by the first or second releasing means and handing off to the first radio base station having a free channel in a communication channel. A featured mobile station. In a mobile station that communicates with a control station having a plurality of radio base stations using a radio channel,
First transmitting means for performing transmission for communication with the control table or another mobile station to the first wireless base station whose position is registered among the plurality of wireless base stations in the control station When,
Receiving means for receiving a busy signal from the first radio base station after the transmission;
By receiving the busy signal, a signal transmitted from a radio base station around the first radio base station among the plurality of radio base stations in the control station is received and the received electric field strength is measured. First handoff means for handing off to a second radio base station that is a radio base station transmitting the signal having the highest received electric field strength among the neighboring radio base stations;
Setting means for setting a handoff control time period that defines a period during which handoff operation is prohibited after handoff by the first handoff means;
Second transmitting means for transmitting to the second radio base station for communication with the control table or another mobile station in the control station;
A determination unit that determines whether or not the transmission by the second transmission unit is performed within the period of the handoff control time period to the second radio base station;
When it is determined by the determining means that the call is made within the period of the handoff control time period, communication with the control table or another mobile station in the control station is started via the second radio base station. A first release means for releasing the handoff control time limit;
A second canceling unit for canceling the handoff control time period when the determination unit determines that the transmission has not been performed within the handoff control time period;
A second handoff means for performing handoff operation by releasing the handoff control time limit by the first or second release means and handing off to the first radio base station having a free channel in a communication channel; A mobile station that shifts to a state in which communication is performed via the first radio base station by handoff by the second handoff means.

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