JP5554894B2 - Mobile terminal and communication method - Google Patents

Description

  The present invention relates to a mobile terminal and a communication method.

As is well known, when the mobile terminal moves from the communication area of the base station where the location is registered into the communication area of another base station, the mobile terminal starts location registration for the other base station. And a portable terminal starts reception of the communication channel transmitted from another base station with the start of position registration with respect to another base station. However, when the mobile terminal is located near the boundary of the communication area of another base station, the mobile terminal and the base station can communicate with each other because the mobile terminal is away from the base station. The mobile terminal may fail to register its location with another base station. Therefore, as described in Non-Patent Document 1 below, the mobile terminal measures the time (100 seconds) until the location registration is re-executed by the location registration retry timer when the location registration fails, When the location registration retry timer times out, location registration is performed again for other base stations.
"2nd generation cordless telephone system standard RCR STD-28" Radio Industry (ARIB)

  By the way, in the above prior art, even if the location registration for another base station fails, the mobile terminal continuously receives the communication channel transmitted from the other base station. However, since the incoming signal is transmitted through the communication channel of the base station that has been registered until the location registration with respect to another base station is successful, the mobile terminal is not able to wait until the location registration with another base station is successful. The incoming signal cannot be received, that is, the incoming signal cannot be received.

  The present invention has been made in view of the above-described circumstances, and provides a mobile terminal and a communication method capable of receiving a communication channel of a base station whose location has been registered earlier than before when location registration to the base station has failed. The purpose is to do.

  In order to achieve the above object, in the present invention, as a first solution for the mobile terminal, if the location registration for the first base station fails, the communication unit that transmits and receives various signals to and from the base station, It is determined whether the strength of the signal received by the communication unit from the registered second base station is at a communicable level, and the strength of the signal of the second base station is at a communicable level If it is determined, a means is provided that includes a control unit that causes the communication unit to receive the communication channel of the second base station.

  In the present invention, as a second solving means relating to the mobile terminal, in the first solving means, when the control unit fails in location registration for the first base station, a predetermined base station detection time has elapsed. A means for determining whether or not the strength of a signal received later from the second base station is at a communicable level is adopted.

  In the present invention, as a third solving means relating to the mobile terminal, in the second solving means, when the control unit fails in position registration with respect to the first base station, a predetermined position registration retry time has elapsed. Later, the communication unit is made to re-execute location registration for the first base station, and the base station detection time is set shorter than the location registration retry time.

  Also, in the present invention, as a first solving means related to the communication method, the communication step of transmitting / receiving various signals to / from the base station, and the second location registration until now when the location registration to the first base station fails. If it is determined whether the signal strength received by the communication step from the base station is at a communicable level, and it is determined that the signal strength of the second base station is at a communicable level, And a control step of causing the communication step to receive the communication channel of the second base station.

  According to the present invention, in the mobile terminal, when the control unit fails in location registration for the first base station, the strength of the signal received by the communication unit from the second base station that has been location registered so far is communicated. If it is determined whether the signal strength of the second base station is at a communicable level, the communication unit receives the communication channel of the second base station. By doing so, when the location registration for the base station fails, the communication channel of the base station whose location has been registered can be received earlier than before.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The present embodiment relates to a PHS (Personal Handyphone System) terminal.
FIG. 1 is a schematic configuration diagram illustrating a wireless communication system including a PHS terminal A according to the present embodiment. The PHS terminal A is a portable terminal in the present embodiment. This wireless communication system includes a PHS terminal A, a base station B1, a base station B2, a switching center C1, a switching center C2, and a network center D.

  The PHS terminal A transmits / receives a control channel and a communication channel to / from the base station B1 or B2. The base stations B1 and B2 are discretely arranged with a predetermined interval, and communicate with the PHS terminal A in the cells S1 and S2 assigned to them. The base station B1 is connected to the exchange C1, and transmits various signals such as a voice incoming signal to the PHS terminal A based on instructions from the exchange C1. Further, the base station B2 is connected to the exchange C2, and transmits various signals to the PHS terminal A based on the exchange C2. FIG. 1 shows that the PHS terminal A is first located in the cell S1 of the base station B1, and then moves in the cell S2 of the base station B2 by moving in the arrow direction. That is, the PHS terminal A first performs location registration with respect to the base station B1, and then performs location registration with respect to the base station B2 by moving the base station B2 to the cell S2.

The exchange C1 is connected to the base station B1 and other base stations (not shown), and the exchange C2 is connected to the base station B2 and other base stations (not shown). The exchange C1 and the exchange C2 are connected to other exchanges not shown through a public network (not shown).
The network center D is connected to the exchange C1 and the exchange C2. Then, in the network center D, location registration information indicating a general calling area of the location registration destination of the PHS terminal A is registered from the exchange C1 or the exchange C2 by the location registration for the base station B1 or the base station B2 by the PHS terminal A Is done. Based on the location registration information, the network center D causes the base station B1 connected to the exchange C1 or the base station B2 connected to the exchange C2 to transmit various signals such as an incoming signal to the PHS terminal A.

Next, the functional configuration of the PHS terminal A will be described with reference to FIG. FIG. 2 is a functional block diagram showing a functional configuration of the PHS terminal A according to the present embodiment. As shown in FIG. 1, the communication unit 1 includes an operation unit 2, a display unit 3, and a control unit 4.
Under the instruction of the control unit 4, the communication unit 1 transmits and receives various signals such as voice signals, data signals, and control signals to and from the base stations B1 and B2 through a control channel or a communication channel.

The operation unit 2 includes various operation keys such as a numeric keypad, direction keys, and various function keys. The operation unit 2 receives user operation instructions for these operation keys and outputs them to the control unit 4.
The display unit 3 is, for example, a liquid crystal display or an organic EL (Electronic Luminescent) display, and displays various screens including images and characters based on image signals input from the control unit 4.

The control unit 4 inputs and outputs signals to and from the internal memory including a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory), and the communication unit 1, the operation unit 2, and the display unit 3. Each interface circuit is configured to control the overall operation of the PHS terminal A based on a control program stored in the ROM, various signals received by the communication unit 1 and operation instructions received by the operation unit 2.
Note that the control program stored in the ROM includes a location registration program, and the control unit 4 executes location registration processing based on the location registration program. Details of the location registration process executed by the control unit 4 will be described later.

Next, the location registration process of the PHS terminal A configured as described above will be described in detail with reference to FIG. FIG. 3 is a flowchart showing the location registration process of the PHS terminal A according to the present embodiment.
First, as described above with reference to FIG. 1, the PHS terminal A is located in the cell S1 of the base station B1, and then moves in the cell S2 of the base station B2 by moving in the direction of the arrow.
The control unit 4 measures the electric field strength of the control channel received by the communication unit 1 from the base station B1, and determines whether the electric field strength of the control channel of the base station B1 is equal to or higher than a level at which communication is possible ( Step S1), if it is determined as “YES” in Step S1, that is, if it is determined that the electric field strength of the control channel received by the communication unit 1 from the base station B1 is equal to or higher than a communicable level. The location registration for the base station B1 is continued, and the communication channel from the base station B1 is continuously received by the communication unit 1.

  When the control unit 4 determines “NO” in step S1, that is, when it is determined that the electric field strength of the control channel received by the communication unit 1 from the base station B1 is less than a level at which communication is possible. Measures the field strength of the control channel received by the communication unit 1 from the base stations B1 and B2 located around the PHS terminal A and other base stations not shown (step S2), and determines the control channel of each base station. A base station field strength list in which the field strength is registered is created (step S3), and based on this base station field strength list, the base station with the strongest field strength of the control channel is determined as the base station B2.

  Then, the control unit 4 causes the communication unit 1 to transmit a location registration request to the base station B2 having the strongest electric field strength of the control channel using the control channel (step S4), and the base station B1 receives the communication channel received by the communication unit 1. The communication channel to be transmitted is switched to the communication channel to be transmitted by the base station B2. (Step S5).

  The control unit 4 determines whether or not the location registration for the base station B2 is successful based on the location registration success / failure information included in the location registration response received from the base station B2 by the communication unit 1 through the control channel (step S6). If “YES” is determined in the step S6, that is, if it is determined that the location registration for the base station B2 is successful based on the location registration success / failure information included in the location registration response, the process is terminated. If the control unit 4 determines “NO” in step S6, that is, if it determines that the location registration for the base station B2 has failed based on the location registration success / failure information included in the location registration response, the location registration is performed. A retry timer and a location registered base station detection timer are started (step S7).

  If the PHS terminal A succeeds in location registration with respect to the base station B2 by the process of step S4, location registration information indicating that the location registration destination of the PHS terminal A is a general call area including the base station B2 is provided. It is registered in the network center D via the exchange C2. Further, when the PHS terminal A fails to register the location with the base station B2 by the process of step S4, location registration information indicating that the location registration destination of the PHS terminal A is a general call area including the base station B1 is provided. It remains registered in the network center D.

  Details of the location registration retry timer and location registered base station detection timer activated in step S6 will be described. The location registration retry timer is a timer that times the time until the communication unit 1 retransmits a location registration request to the base station B2 when location registration fails. In the PHS terminal A in the present embodiment, the communication unit 1 retransmits a location registration request to the base station B2 in accordance with the description of “2nd generation cordless telephone system standard RCR STD-28” (issued by the radio industry). The time until transmission, that is, the time until the location registration retry timer times out is defined as “100 seconds”.

  When the location registration has failed, the location registered base station detection timer is configured to start remeasurement of the electric field strength of the control channel of the base station B1 registered in the network center D as the location registration destination of the PHS terminal A. It is a timer that measures time. The time until the location registration completed base station detection timer times out is shorter than 100 seconds, which is the time until the location registration retry timer times out. It is assumed that the time until the location registered base station detection timer times out is “15 seconds”.

  After step S7, the control unit 4 determines whether or not the position-registered base station detection timer has timed out by measuring 15 seconds (step S8). If it is determined “YES” in step S8, that is, the position If it is determined that the registered base station detection timer has timed out, the communication unit 1 remeasures the electric field strength of the control channel received from the base station B1 (step S9), and the electric field strength of the control channel of the base station B1 is It is determined whether or not the communication is possible or not (step S10).

  If the control unit 4 determines “NO” in step S10, that is, if the electric field strength of the control channel of the base station B1 received by the communication unit 1 is less than a level at which communication is possible, The registered base station detection timer is started again (step S11), and the process proceeds to step S8. If the control unit 4 determines “YES” in step S10, that is, if the electric field strength of the control channel of the base station B1 received by the communication unit 1 is equal to or higher than a level at which communication is possible, The communication channel received by the communication unit 1 is switched from the communication channel transmitted by the base station B2 to the communication channel transmitted by the base station B1 (step S12), and the process ends.

  When it is determined as “NO” in step S8, that is, when it is determined that the position registration completed base station detection timer has not timed out, the control unit 4 timed out the position registration retry timer due to the time measurement of 100 seconds. If it is determined as “NO” in step S13, that is, if it is determined that the position registration retry timer has not timed out, the process proceeds to step S8. If it is determined “YES” in S13, that is, if it is determined that the location registration retry timer has timed out, the base station B2 is caused to transmit a location registration request to the communication unit 1 through the control channel (step S14).

  The control unit 4 determines whether or not the location registration for the base station B2 is successful based on the location registration success / failure information included in the location registration response received from the base station B2 by the communication unit 1 through the control channel (step S15). If “YES” is determined in step S15, that is, if it is determined that the location registration for the base station B2 is successful based on the location registration success / failure information included in the location registration response, the process is terminated. If the control unit 4 determines “NO” in step S15, that is, if it determines that the location registration for the base station B2 has failed based on the location registration success / failure information included in the location registration response, the location registration is performed. The retry timer is started again (step S16), and the process proceeds to step S8.

As described above, in the PHS terminal A, when the location registration for the base station B2 fails, the control unit 4 activates the location registered base station detection timer together with the location registration retry timer, and the location registered base It is possible to measure the electric field strength of the control channel of the base station B1 registered in the network center D as the location registration destination of the PHS terminal A by timeout of the station detection timer, and to communicate the electric field strength of the control channel of the base station B1. When the location registration has failed by switching the communication channel received by the communication unit 1 from the communication channel transmitted by the base station B2 to the communication channel transmitted by the base station B1. The communication channel of the base station whose location has been registered can be received earlier than before.
Further, in the PHS terminal A, by setting the time until the position registration completed base station detection timer times out to 15 seconds shorter than the time until the position registration retry timer times out (100 seconds), it is possible to wait for 100 seconds. Can also receive the communication channel of the registered base station.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, For example, the following modifications can be considered.
(1) In the above embodiment, the time until the position-registered base station detection timer times out is 15 seconds, but the present invention is not limited to this.
The time until the location registration base station detection timer times out may be, for example, 5 seconds, 10 seconds, or 20 seconds as long as it is shorter than 100 seconds, which is the time until the location registration retry timer times out. .

It is a schematic block diagram which shows a radio | wireless communications system provided with PHS terminal A which concerns on one Embodiment of this invention. It is a functional block diagram which shows the function structure of the PHS terminal A which concerns on embodiment which concerns on one Embodiment of this invention. It is a flowchart which shows the location registration process of PHS terminal A which concerns on one Embodiment of this invention.

Explanation of symbols

  A ... PHS terminal, B1, B2 ... Base station, C1, C2 ... Switching office, D ... Network center, 1 ... Communication part, 2 ... Operation part, 3 ... Display part, 4 ... Control part

Claims (4)

A communication unit that transmits and receives various signals to and from the base station;
If location registration with respect to the first base station fails, it is determined whether or not the strength of the signal received by the communication unit from the second base station that has been registered so far is at a communicable level, and the second And a control unit that causes the communication unit to receive the communication channel of the second base station when it is determined that the signal strength of the base station is at a communicable level. .   If the location registration with respect to the first base station fails, the control unit determines whether the strength of the signal received from the second base station after a predetermined base station detection time has passed can be communicated. The mobile terminal according to claim 1, wherein the mobile terminal is determined.   When the location registration with respect to the first base station fails, the control unit causes the communication unit to re-execute the location registration with respect to the first base station after a predetermined location registration retry time has elapsed, and the base station The mobile terminal according to claim 2, wherein a detection time is set shorter than the location registration retry time. A communication step for transmitting / receiving various signals to / from the base station;
If location registration with respect to the first base station fails, it is determined whether or not the strength of the signal received by the communication step from the second base station that has been registered so far is at a communicable level, and the second And a control step of causing the communication step to receive the communication channel of the second base station when it is determined that the signal strength of the base station is at a communicable level. .

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