JP2012209777A - Mobile terminal device, and communication control method and program for mobile terminal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure that a mobile terminal device receives incoming call notification which is transmitted from a handoff source base station during a time period from when handoff takes place to when the location registration is updated.SOLUTION: A mobile terminal device 10 has two receiving units, which are a first receiving unit and a second receiving unit. After handoff from a source base station 20A to a target base station 20B, the first receiving unit monitors for incoming call notification from the target base station 20B while the second receiving unit monitors for incoming call notification from the source base station 20A. If incoming call notification is received from the source base station 20A, communication with the source base station 20A is made, and if not received, communication with the target base station 20B is made.

Description

  The present invention relates to a mobile terminal device used in a cellular communication network and a communication control method executed by the mobile terminal device. The present invention also relates to a program to be executed by a mobile terminal device.

  In a mobile communication system employing a cell system, a situation in which a mobile terminal apparatus moves from one cell to the next cell naturally occurs. At this time, handoff (handover) for automatically switching to the radio channel of the transfer destination cell is performed between the mobile terminal device and the base station (see, for example, Patent Document 1). Thereby, communication is not disconnected even in a situation where the mobile terminal device moves between a plurality of cells during communication.

JP 2007-174282 A

  After performing the handoff, the mobile terminal updates the location registration for the network. By updating the location registration, the handoff destination base station can manage the mobile terminal device as being located in its own cell. However, there may be a slight time lag between the time when handoff is performed and the time when the location registration update is completed.

  Unless the location registration is updated, the handoff source base station still recognizes that it should manage the mobile terminal device itself, so that the handoff source base station will notify the mobile terminal device of incoming calls. Become. For this reason, a situation may occur in which the incoming call notification is transmitted from the handoff source base station even though the channel of the mobile terminal device has already been switched to the handoff destination base station. In this case, the mobile terminal device cannot receive incoming calls. Thus, in the present situation, there is a possibility that the mobile terminal apparatus cannot receive the incoming call notification after the handoff occurs. Since this incoming notification depends on the control on the base station side, it is very difficult to avoid such an incoming notification error on the mobile terminal device side as it is.

  It is an object of the present invention to provide a mobile terminal device, a mobile terminal device communication control method, and a program that can solve the above-described problems.

  The present invention relates to at least two receiving units that receive signals wirelessly transmitted through a set channel and one receiving unit in which a channel of a handoff source base station is set as a channel of a handoff destination base station. Handoff control means for executing handoff to be switched, and after the execution of the handoff, the one receiving unit monitors reception of an incoming notification from a base station that is a handoff destination, and the other receiving unit other than the one receiving unit performs handoff A mobile terminal apparatus comprising: an incoming call notification monitoring control unit that monitors reception of an incoming call notification from a channel of an original base station.

  In addition, the present invention provides a handoff destination base station for one receiving unit in which a channel of a handoff source base station is set among at least two receiving units that receive signals transmitted by radio using the set channel. A handoff control procedure for executing handoff to switch to another channel, and after the handoff is performed, reception of an incoming notification from a handoff destination base station is monitored by the one receiving unit, and reception other than the one receiving unit is received. A communication control method for a mobile terminal apparatus comprising: an incoming call notification monitoring control procedure for monitoring reception of an incoming call notification from a channel of a handoff source base station by a unit.

  In addition, the present invention relates to one receiving unit in which the channel of the handoff source base station is set, out of at least two receiving units that receive a signal wirelessly transmitted by the set channel to the mobile terminal device. A handoff control procedure for performing handoff switching to a channel of a handoff destination base station, and after the handoff is performed, the one receiving unit monitors reception of an incoming notification from the handoff destination base station, and the one receiving unit This is a program for executing an incoming call notification monitoring control procedure for monitoring reception of an incoming call notification from the channel of the base station that is the handoff source other than the receiving unit.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to receive an incoming call notification more reliably also in the timing after a mobile terminal apparatus performs handoff.

It is a figure which shows the structural example of the radio | wireless communications system in embodiment of this invention. It is a figure which shows the structural example of the mobile terminal device 10 in embodiment of this invention. 4 is a flowchart illustrating an example of a communication control processing procedure executed by the mobile terminal device 10. 7 is a flowchart illustrating another example of a processing procedure of communication control executed by the mobile terminal device 10.

FIG. 1 schematically shows an overall configuration example of a communication system corresponding to a mode (embodiment) for carrying out the present invention. The communication system corresponding to the present embodiment corresponds to mobile communication employing a cell system. In the figure, mobile terminal apparatus 10 and base stations 20A and 20B are shown.

  The mobile terminal device 10 is a terminal device configured to be portable by a user, and a specific example thereof is a mobile phone. Further, in this figure, two base stations 20A and 20B are shown. It is assumed that the cell 100A of the base station 20A and the cell 100B of the base station 20B are formed adjacent to each other. A cell indicates a communicable range from a base station.

  In the vicinity of the boundary between the cell 100A and the cell 100B, regions overlapping each other with a weak electric field are formed. Such an area is also called a fringe area or the like, and may not be able to receive radio waves stably. In the figure, a range where the cell 100A and the cell 100B indicated by the wavy line overlap is shown as a fringe area 101.

  In FIG. 1, the following situation is assumed. That is, the mobile terminal apparatus 10 was initially located at a location where the cell 100A can receive radio waves from the base station 20A with sufficient strength. However, as a result of the mobile terminal apparatus 10 moving in the direction of the cell 100B, the mobile terminal apparatus 10 is located in the fringe area 101. When such a situation is reached, the mobile terminal apparatus 10 may perform a handoff process with the base station 20B in order to switch to a channel corresponding to the cell 100B. In this case, the base station 20A is the handoff source, and the base station 20B is the handoff destination. Therefore, hereinafter, the base stations 20A and 20 are also referred to as a handoff source base station 20A and a handoff destination base station 20B, respectively.

  It is assumed that the mobile terminal apparatus 10 performs handoff with the handoff destination base station 20B as described above. After the handoff is performed, the location registration to the network is updated. However, for example, the location registration update may not be completed even after a certain period of time. Until the update of the location registration is completed, the handoff source base station 20A still recognizes that the mobile terminal device 10 is located in its own cell 100A. Therefore, the incoming call notification to the mobile terminal device 10 at this time is transmitted from the handoff source base station 20A. However, at this stage, the mobile terminal apparatus 10 itself has already established a handoff with the handoff destination base station 20B, and thus has switched to the channel of the handoff destination base station 20B. For this reason, there arises a problem that the mobile terminal apparatus 10 cannot receive the incoming call notification from the handoff source base station 20A. In this way, there is a possibility that the incoming call notification cannot be received after the mobile terminal apparatus 10 performs the handoff.

  Therefore, in the present embodiment, even if an incoming call notification is transmitted from the handoff source base station 20A until the location registration is completed after the handoff, this can be received.

  FIG. 2 shows a configuration example of the mobile terminal apparatus 10. The mobile terminal apparatus 10 shown in this figure includes a first reception unit 11-1, a second reception unit 11-2, a transmission unit 12, a transmission / reception processing unit 13, and an antenna 14.

  The first receiving unit 11-1 receives a reception signal received by the antenna 14 and executes predetermined reception processing such as demodulation. As the predetermined reception process, in the present embodiment, as described later, an intermittent reception operation at the time of standby, incoming call notification monitoring, and the like are executed. The second receiver 11-2 is a part having the same function as the first receiver 11-1. Normally, only one functional unit corresponding to the receiving unit 11 is provided in the mobile terminal. In the present embodiment, a plurality of such functional units are provided.

  The transmission unit 12 performs a predetermined process on the transmission signal to be transmitted from the antenna 14. The transmission / reception processing unit 13 executes control and processing related to signal transmission / reception. It is a part which implement | achieves communication of the mobile terminal device 10 by performing control with respect to the 1st receiving part 11-1, the 2nd receiving part 11-2, and the transmission part 12. FIG.

  The flowchart of FIG. 3 shows an example of a processing procedure for communication control executed by the mobile terminal apparatus 10 having the above configuration. Note that the processing procedure shown in this figure can be considered to be realized by the transmission / reception processing unit 13 executing a program.

  In the flowchart of FIG. 3, variables n and m are used in distinguishing and specifying the first receiving unit 11-1 and the second receiving unit 11-2. The variables n and m are set such that if one is “1”, the other is “2”. That is, for example, if “1” is assigned to the variable n and “2” is assigned to the variable m, the n-th receiving unit 11-n identifies the first receiving unit 11-1 and the m-th receiving unit 11 -M specifies the second receiving unit 11-2. In the following description, first, it is assumed that “1” is assigned to the variable n and “2” is assigned to the variable m.

  First, in step S101, the transmission / reception processing unit 13 sets the channel of the handoff source base station 20A and is in a standby state. At this time, the mobile terminal apparatus 10 is in a position where it can receive a sufficiently strong radio wave from the handoff source base station 20A in the cell 100A. In addition, in this standby state, the transmission / reception processing unit 13 controls the first receiving unit 11-1 (n = 1) to perform an intermittent receiving operation in step S102. At this time, the second receiving unit 11-2 (m = 2) is in the off state without executing the receiving operation.

  Under the standby state due to intermittent reception in step S102, the transmission / reception processing unit 13 waits for a handoff to occur in step S103. Here, it is assumed that the mobile terminal device 10 has moved to the fringe area 101 or the cell 100B. In response to this, the transmission / reception processing unit 13 controls the first reception unit 11-1 (n = 1) and the transmission unit 12 to execute communication for handoff with the handoff destination base station 20B. As a result, when a handoff to the handoff destination base station 20B is established, it is determined in step S103 that a handoff has occurred, and the process proceeds to step S104 and subsequent steps. Note that the transmission / reception processing unit 13 that executes handoff as described above corresponds to, for example, the handoff control means described in the claims.

  In step S104, the transmission / reception processor 13 performs the intermittent reception operation in a state where the first receiver 11-1 (n = 1) is switched to the channel of the handoff destination base station 20B. Thereby, the first reception unit 11-1 (n = 1) is allowed to monitor the incoming call notification transmitted from the handoff destination base station 20B. At the same time, the transmission / reception processor 13 sets the channel of the handoff source base station 20A by turning on the second receiver 11-2 (m = 2) in step S105. As a result, the second receiver 11-2 (m = 2) monitors the incoming call notification transmitted from the handoff source base station 20A. Note that the transmission / reception processing unit 13 that executes control for monitoring incoming notifications in steps S104 and S105 corresponds to the incoming notification control means described in the claims.

  In a normal handoff procedure, for example, a standby state corresponding to only the channel of the handoff destination base station 20B is set immediately after a new handoff occurs. In contrast, in the present embodiment, after handoff occurs as described above, first, a state is set in which the incoming notification of the handoff destination base station 20B and the handoff source base station 20A can be monitored. As a result, for example, even when an incoming call notification is transmitted from the handoff source base station 20A, it can be reliably received as long as a certain electric field strength is obtained.

  Then, after starting monitoring of incoming notifications from the handoff destination base station 20B and the handoff source base station 20A as described above, the transmission / reception processing unit 13 starts from the handoff source base station 20A within a predetermined time, for example, in step S106. Wait for the incoming notification to be received. At this time, if the second reception unit 11-1 (m = 2) receives the incoming call notification transmitted from the handoff source base station 20A, the transmission / reception processing unit is transmitted from the second reception unit 11-2 (m = 2). 13 is notified to that effect. In response to this, the transmission / reception processing unit 13 determines that an incoming call notification has been received in step S106, and proceeds to the procedure after step S107.

  In response to the incoming call notification, the transmission / reception processing unit 13 executes processing for establishing communication with the communication partner via the handoff source base station 20A in step S107. Then, the transmission / reception processing unit 13 normally terminates the communication in step S108 in response to, for example, a communication termination operation on the mobile terminal device 10 or a disconnection from the communication partner side. Thus, when communication via the handoff source base station 20A is normally performed, it is estimated with high probability that communication with the handoff source base station 20A is possible with sufficient electric field strength. The

  Therefore, the transmission / reception processing unit 13 exchanges the values of the variables m and n in step S109. Specifically, until now, since the variable n is “1” and the variable m is “2”, the variable n is “2” and the variable m is “1” in step S109. Then, the process returns to step S101. Accordingly, the standby state can be continuously set for the first receiving unit 11-1 (m = 1) in which the channel of the handoff source base station 20A has been set. The transmission / reception processing unit 13 that executes the procedure of executing step S109 and returning to step S101 corresponds to, for example, the first communication control unit described in the claims.

  On the other hand, if it is determined in step S106 that the incoming notification from the handoff source base station 20A has not been received within a certain time, the handoff destination base station 20B is more reliable in terms of electric field strength and the like. It can be inferred that there is a high possibility of receiving an incoming call notification.

  Therefore, the transmission / reception processing unit 13 in this case updates the location registration in step S110. When the location registration is completed in step S110, the base station 20B that has been the handoff destination so far is treated as a handoff source. In addition, the transmission / reception processing unit 13 returns to step S101. As a result, the standby state for the handoff destination base station 20B is set for the first receiving unit 11-1 (n = 1) that has already been switched to the channel of the handoff destination base station 20B (step S101). A receiving operation is performed (step S102). At this time, the second receiving unit 11-2 (m = 2), to which the channel of the base station 20A has been set, is turned off. In this way, in the standby state before the handoff occurs, both the two receiving units 11 are not turned on, but only one receiving unit 11 in which the channel of the base station 20 that is the handoff source at that time is set on. To do. Thereby, compared with the case where the two receiving parts 11 are steadily turned on, power consumption can be suppressed. The transmission / reception processing unit 13 that executes the procedure of returning from step S110 to step S101 corresponds to the second communication control unit described in the claims.

  The flowchart of FIG. 4 shows another processing procedure example as communication control executed by the mobile terminal device 10. In this figure, the same steps as those in FIG. 3 are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 4, the transmission / reception processing unit 13 performs the determination in step S107-1 after establishing communication with the communication partner via the handoff source base station 20A in step S107. In step S107-1, the transmission / reception processing unit 13 determines whether or not communication disconnection has occurred due to the weak electric field strength of the cell 100A when performing communication with the communication partner via the handoff source base station 20A. Judge about.

  If it is determined that no disconnection has occurred in step S107-1, for example, if communication ends normally, the processing in steps S108 and S109 is performed as in FIG. Return to S101.

  On the other hand, if it is determined in step S107-1 that disconnection has occurred, for example, the electric field strength of cell 100A is weaker than when communication was established in step S107, and communication can be restored thereafter. It can be estimated that the sex is low. Therefore, the transmission / reception processing unit 13 in this case proceeds to the procedure after step S110. That is, the mobile terminal apparatus 10 is set to give priority to communication via the handoff destination base station 20B.

  As described above, in the present embodiment, even if there is an incoming call notification from the handoff source base station 20A during the period from the handoff occurrence to the location registration update, the incoming call notification can be received without missing. It becomes possible. In addition, according to the presence / absence of an incoming notification from the handoff source base station 20A after the handoff occurs, appropriately determine which of the handoff source base station 20A and the handoff destination base station 20B should communicate with after the handoff occurs Can do.

Note that the processing procedure described in this embodiment can be regarded as a method having a series of these procedures. Further, it can be understood as a program for causing a computer to execute these series of procedures or a recording medium for storing the program. Examples of the recording medium include a Blu-ray Disc (registered trademark), a DVD (Digital Versatile Disk), an HDD (hard disk), a memory card, and the like.
In FIG. 3 and FIG. 4 used for the description of the above processing, “Y” indicates Yes, and “N” indicates No.

DESCRIPTION OF SYMBOLS 10 Mobile terminal device 11-1 1st receiving part 11-2 2nd receiving part 12 Transmitting part 13 Transmission / reception processing part 14 Antenna 20A Handoff source base station 20B Handoff destination base station

Claims (7)

At least two receivers for receiving signals wirelessly transmitted by the set channel;
Handoff control means for executing handoff for switching to the channel of the handoff destination base station for one receiving unit in which the channel of the handoff source base station has been set;
After execution of the handoff, the reception of the incoming notification from the handoff destination base station is monitored by the one receiving unit, and the incoming notification from the channel of the base station of the handoff is received by another receiving unit other than the one receiving unit. Incoming notification monitoring control means for monitoring the reception of
A mobile terminal device comprising: A first communication control unit configured to set a standby state for the handoff source base station in the other receiver unit when an incoming call notification from the handoff source base station is received by the other receiver unit; Prepare
The mobile terminal apparatus according to claim 1. The first communication control means includes
When setting the standby state for the base station of the handoff source to the other receiver, the one receiver is turned off.
The mobile terminal apparatus according to claim 2. When the incoming notification is not received from the handoff source base station by the other receiving unit, the location registration is updated according to the handoff execution, and the standby state for the handoff destination base station is set. A second communication control means for setting in the one receiving unit;
The mobile terminal device according to claim 1, wherein the mobile terminal device is a mobile terminal device. The second communication control means includes:
When the standby state for the base station of the handoff destination is set in the one receiver, the other receiver is turned off.
The mobile terminal apparatus according to claim 4. Of the at least two receiving units that receive signals wirelessly transmitted by the set channel, handoff for switching to the channel of the handoff destination base station is performed for one receiving unit in which the channel of the handoff source base station is set. A handoff control procedure to be performed;
After execution of the handoff, the reception of the incoming notification from the handoff destination base station is monitored by the one receiving unit, and the incoming notification from the channel of the base station of the handoff is received by another receiving unit other than the one receiving unit. Incoming notification monitoring control procedure to monitor the reception of,
A communication control method for a mobile terminal device, comprising: Mobile terminal device
Of the at least two receiving units that receive signals wirelessly transmitted by the set channel, handoff for switching to the channel of the handoff destination base station is performed for one receiving unit in which the channel of the handoff source base station is set. A handoff control procedure to be performed;
After execution of the handoff, the reception of the incoming notification from the handoff destination base station is monitored by the one receiving unit, and the incoming notification from the channel of the base station of the handoff is received by another receiving unit other than the one receiving unit. Incoming notification monitoring control procedure to monitor the reception of,
A program for running

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