JP2008211680A - Radio communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio communication terminal which can correspond to a plurality of communication forms, and can capture a communication system efficiently and at a small power consumption when a transmission operation was carried out even in a state that is determined as out of range. <P>SOLUTION: In the radio communication terminal, upon an out-of-range transmission processing, when each communication system in an MRU is scanned, a phase i is determined in response to an elapsed time from a transition time to the out-of-range state. In response to a time when the communication system at the time of a state within the range (waiting state) is captured, an index Iprior determined for each communication system and stored in the MRU of a storage part 7 is compared with a threshold value THprior (i) in response to the phase i (ST13), thereby deciding whether or not the communication system is scanned. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention particularly relates to a radio communication terminal suitable for use in a multiband radio communication system.

A wireless communication terminal applied to CDMA (Code Division Multiple Access) communication starts a capturing operation of a usable communication system when the power is turned on. Here, the “communication system” refers to a compatible frequency in a communication method that can be used by the wireless communication terminal.
In particular, in the CDMA2000_1x system, first, location registration processing is performed in a communication system that can be captured after the power is turned on. The wireless communication terminal stores in advance frequency information that can be handled by itself, and measures the signal strength of the frequency. When a predetermined strength or higher is detected, the presence of a pilot channel at this frequency is confirmed, synchronization is established with the pilot channel using a PN code to obtain a synchronization channel, and base station information (PN code offset amount, etc.) ) To get. Then, a base station with favorable conditions is identified and registered, and a standby state is entered.
If the signal strength of the received signal from the base station deteriorates despite waiting in this way, the wireless communication terminal attempts to hand over to another base station. However, if there is no other base station that can stand by and the signal from the base station that is in communication is further weakened and cannot be acquired, the wireless communication terminal determines that the device has fallen out of service.
The wireless communication terminal is in a range for returning to the area in preparation for a case where it is in a state where it can be captured again due to a subsequent change in the state of the radio wave around the own device or a movement of the own device in a state determined to be out of range. Performs return capture operation. Specifically, a trial for acquiring a frequency that can be awaited is repeated at a predetermined cycle to enter a system scan state for searching for a base station.

By the way, when the wireless communication terminal is out of the service area, the wireless communication terminal turns on a flag (out of service flag) indicating that it is out of service internally. In such a situation, even if the user performs a call operation, it is unlikely that the user can make a call while the out-of-service flag is ON, and the call process has not been started for power saving.
In addition, once it is determined that the service area is out of service area, the service area return process is performed at a predetermined cycle. However, the time required for the service area return is ignored due to limited communication methods for attempting a system scan for recovery. It is impossible. For example, considering the case where the wireless communication terminal is stored in a metal coin locker, etc., the metal coin locker will be surrounded by radio wave obstructions if put in, but if it is put out, the radio wave environment is good The environment. In this way, when the radio wave environment around the wireless communication terminal changes drastically in a short time (for example, from a coin locker), it is only necessary to return to the area immediately, but it will return immediately unless the timing of the area return capture operation is reached. Because it is not possible, it will take some time before communication is possible. Further, if the return-to-area acquisition process is performed at a shorter cycle, the return to the area is quicker, but the power consumption increases when out of the area. Furthermore, even if the area return process is performed, if the capture target cannot be identified efficiently, it takes time to return to the area.

In order to solve the above-described problem, a technique is known in which a capturing operation of a communication system for return-in-range processing is performed at predetermined intervals (see, for example, Patent Document 1).
In addition, a technology is also known that enables automatic transmission when a call operation is performed, even when the user is out of the call area, even if the user enters the service area (see, for example, Patent Document 2).
Furthermore, in the case of reconnection when communication is interrupted during data communication, if a predetermined time or more has passed since communication was interrupted, reconnection processing is not performed because it is unnecessary reconnection. A technique is also known (see, for example, Patent Document 3).
JP 2004-15312 A " Japanese Patent Laid-Open No. 11-178064 JP 2005-94228 A

As in the case of the coin locker described above, it is only determined that the out-of-service state continues because the timing of the return-to-service processing has not arrived even though the situation can actually capture the communication system. There may be no. In such a case, even if a situation requiring an outgoing call occurs, the user makes a call because the user decides that the wireless communication terminal is out of the service area, even though the user wants to make an early call. I can't.
According to the technique disclosed in Patent Document 1 described above, although processing for returning to the outside of the service area is disclosed, a plurality of frequency bands (for example, 800 MHz, 2 GHz) are recently used in one wireless communication terminal. In the case of such a terminal, since the number of target frequency bands to be scanned is large in such a terminal, it takes time to scan itself for determining the return to the area, Even if the frequency band to be recovered could be captured, there was a disadvantage that the time required for this would be increased and the power consumption would increase due to the occurrence of long-time scanning. Further, even with the technique disclosed in Patent Document 2, the call processing itself cannot be performed until the mobile phone returns to the service area. Furthermore, in the technique disclosed in Patent Document 3, only the determination of restarting communication is disclosed, and the call processing outside the service area is not disclosed.

Therefore, if the return processing from the out-of-service area to the within-service area is performed efficiently, the wireless communication terminal holds the communication system captured in the past in a storage area called MRU (Most Recent Used) in time series, After that, it can be assumed that scanning will be performed one by one from the latest communication system stored in the MRU.
The possibility that the wireless communication terminal scans retroactively from the latest communication system stored in the MRU can communicate with a communication system that has performed communication closer in time. This is because it seems to be expensive.

  However, in the case where a long time has passed since the transition to the out-of-service state, the situation of the communication environment or the like has changed significantly compared to the time when communication was performed with the communication system stored in the MRU. It is not always possible that the latest communication system stored in the MRU can be captured. Nevertheless, all the communication systems stored in the MRU have the disadvantage that it is not preferable to scan uniformly from the latest one in terms of power saving and shortening the time required for scanning. .

Further, a conventional wireless communication terminal has a list called a PRL (Preferred Roaming List) in which priorities of communication systems that can be captured are determined in advance, and the communication stored in the above-described MRU in the out-of-service state. When communication with the system could not be performed, for example, a communication system having a higher priority on the PRL is scanned in order and a communication system capable of communication is captured. However, even when the wireless communication terminal is communicating with the communication system described in the PRL, the wireless communication terminal periodically communicates with a higher-order communication system if it is not communicating with the communication system at the highest level of the PRL. It is like that.
As described above, when scanning is performed according to the PRL, the situation around the wireless communication terminal changes every moment, and thus scanning in the order of the priority of the PRL is not always an efficient scanning order. In some cases, the scan order is rather inefficient. In such a case, as in the case of scanning the communication system stored in the MRU described above, there is a disadvantage that it is not preferable from the viewpoint of power saving and shortening of the scan time.

  The present invention has been made on the basis of the above-described problems. In a wireless communication terminal that can handle a plurality of communication methods, the communication system is captured when a call operation is performed even in a state determined to be out of service. It is an object of the present invention to provide a wireless communication terminal that can efficiently perform power consumption with low power consumption.

  In order to solve the above-described problem, a wireless communication terminal according to a first invention is a wireless communication terminal that performs wireless communication with a plurality of base stations, and selects one from a plurality of communication systems. A communication unit that performs wireless communication, a control unit that switches communication systems used by the communication unit to perform communication by wireless communication, and a storage unit that can store information related to a plurality of communications, the control The storage unit associates the acquisition history information related to the communication system that has been successfully acquired among the plurality of communication systems in the range and the acquisition time information that is information related to the acquisition time in the storage unit, and stores them in the out-of-service state. When a call is requested, out of the communication systems in the acquisition history information stored in the storage unit, the communication unit tries the acquisition in order from the communication system having the longer acquisition time, and the acquisition is performed. A connection process of the communication with respect to the communication system.

  Preferably, the time information is a time when the control unit captures a communication system corresponding to the time information in a range, and the measured time reaches a first predetermined threshold value. Is an integer value incremented by one.

  Preferably, the control unit counts an elapsed time from an out-of-service transition when detecting a transition to an out-of-service transition, and causes the communication unit to perform a capture attempt according to the length of the elapsed time. Determine the number of communication systems.

  Preferably, when the elapsed time is smaller than a second predetermined threshold value, the control unit causes the communication unit to attempt acquisition on all communication systems in the acquisition history information. If the elapsed time is greater than or equal to a second predetermined threshold, the communication unit causes the communication unit to perform acquisition every time the elapsed time exceeds a plurality of predetermined thresholds. Reduce the number of communication systems until zero.

  Preferably, the storage unit stores reference priority order information related to a priority order when performing a capture trial for the plurality of communication systems, and the control unit stores all the communication systems in the capture history information. On the other hand, if the acquisition is not successful, the communication unit is caused to try to acquire the communication system according to the priority order of the reference priority order information.

  Preferably, when the control unit causes the communication unit to attempt acquisition of the communication system according to the priority of the reference priority information, the control unit includes the communication history information in the acquisition history information that has already been attempted to acquire. The communication system is not allowed to attempt acquisition.

  According to the present invention, in a wireless communication terminal capable of supporting a plurality of communication methods, even when a call operation is performed even in a state determined to be out of service, the communication system is captured efficiently and with low power consumption. It is possible to provide a wireless communication terminal that can be used.

Hereinafter, a mobile phone 100 will be described as an example of the wireless communication terminal of the present invention.
FIG. 1 is a block diagram showing an internal configuration of the mobile phone 100.
As shown in FIG. 1, the mobile phone 100 includes a communication unit 1, an operation unit 2, an audio processing unit 3, a speaker 4, a microphone 5, a display unit 6, a storage unit 7, and a control unit 8. Have

FIG. 2 is a diagram illustrating an example of the appearance of the mobile phone 100.
As shown in FIG. 2, in the mobile phone 100, an upper housing 101 and a lower housing 102 are connected by a hinge portion 103 so as to be opened and closed.
2A shows a state where the casing of the mobile phone 100 is opened, and FIG. 2B shows a state where the casing of the mobile phone 100 is closed.
The upper housing 101 includes a speaker 4 and a display unit 6.
The lower housing 102 includes the microphone 5 and the operation unit 2.

  The communication unit 1 transmits / receives a radio signal to / from the base station via a channel assigned by any of a plurality of base stations. The communication unit 1 can transmit and receive wireless signals in a plurality of frequency bands. Specifically, the current frequency band (old 800 MHz band), a new frequency band (new 800 MHz band), and high-frequency frequencies Wireless signals can be transmitted and received using a band (2 GHz band).

In the communication systems having different frequency bands, the band class defined by 3GPP2 (3rd Generation Partnership Project 2) is used as an identification number for identifying the frequency band between the base station and the mobile phone. A code called is given.
For example, in the information notified from one base station to the mobile phone, in the neighbor base station list (Neighbor List), etc., this band class is used to notify the mobile phone of communication systems existing around the mobile phone. Is used. The current frequency band (old 800 MHz band) is classified as band class 3, the new frequency band (new 800 MHz band) is classified as band class 0, and the high frequency band (2 GHz band) is classified as band class 6.
Further, when the communication unit 1 detects that the mobile phone 100 is out of the service area, the communication unit 1 performs out-of-service processing under the control of the control unit 8 described later. The out-of-service processing will be described in detail later.

The operation unit 2 has keys to which various functions are assigned, such as a power key, a call key, a numeric key, a character key, a direction key, a determination key, and a call key. These keys are operated by the user. If so, a signal corresponding to the operation content is generated and input to the control unit 8 as a user instruction.
The audio processing unit 3 processes an audio signal output from the speaker 4 and an audio signal input from the microphone 5. That is, the audio input from the microphone 5 is amplified, analog-to-digital converted, and further subjected to signal processing such as encoding, converted into digital audio data, and output to the control unit 8. Further, the audio data supplied from the control unit 8 is subjected to signal processing such as decoding, digital-analog conversion, amplification, etc., converted into an analog audio signal and output to the speaker 4.

The display unit 6 is configured using a display device such as a liquid crystal display panel or an organic EL (Electro-Luminescence) panel, for example, and displays an image corresponding to a video signal supplied from the control unit 8. For example, various information and images such as the phone number of the callee at the time of outgoing call, the phone number of the other party at the time of incoming call, the contents of received mail and outgoing mail, date, time, remaining battery level, success / failure of outgoing call, standby screen, etc. To do.
The storage unit 7 stores various data used for various processes of the mobile phone 100. For example, a computer program provided in the control unit 8, an address book for managing personal information such as a telephone number or an email address of a communication partner, an audio file for playing a ringtone or an alarm sound, an image file for a standby screen, Various setting data, temporary data used in the program processing, etc. are stored. The above-described storage unit 7 is configured by, for example, a nonvolatile storage device (nonvolatile semiconductor memory, hard disk device, optical disk device, etc.), a randomly accessible storage device (eg, SRAM, DRAM), or the like.

The control unit 8 comprehensively controls the overall operation of the mobile phone. That is, various processes of the mobile phone (voice calls performed via a circuit switching network, creation and transmission / reception of e-mails, browsing of Internet websites, etc.) are executed in an appropriate procedure according to the operation of the operation unit 2. Thus, the operation of each block described above (transmission / reception of signals in the communication unit 1, input / output of audio in the audio processing unit 3, display of images on the display unit 6, etc.) is controlled.
The control unit 8 includes a computer (microprocessor) that executes processing based on a program (operating system, application program, etc.) stored in the storage unit 7, and performs the above-described processing according to a procedure instructed in this program. Execute. That is, instruction codes are sequentially read from programs such as an operating system and application programs stored in the storage unit 7 to execute processing.

The control unit 8 also performs various communication processes for controlling the communication unit 1 to perform wireless communication with a base station (not shown). In the out-of-service state, a number of base stations are scanned to find a base station that can perform wireless communication.
First, the control unit 8 performs the following operation when the mobile phone 100 is turned on and starts communication.

In accordance with PRL (Preferred Roaming List), which is reference priority information stored in advance in the storage unit 7, the signal strength of each of a plurality of frequency bands is measured. The PRL is a list in which information (band class / frequency, primary / secondary channel identifier, used channel identification code, etc.) about communication systems in all frequency bands that can be captured by the wireless communication terminal is stored. When it is detected that the signal strength of each frequency in the PRL is greater than or equal to a predetermined strength, the presence of a pilot channel in this frequency band is recognized. When the pilot channel is acquired, the PN code from the base station and the replica PN code prepared by the control unit 8 are correlated to establish synchronization, and the synchronization channel is acquired from the base station. When the synchronization channel can be acquired, the overhead information is acquired by the paging channel, and the parameters for receiving the paging channel are changed based on the acquired overhead information.
In this way, the control unit 8 can determine which base station in the PRL is communicable, and performs location registration processing for a base station with good conditions (such as strong communication strength) Communication with the station is established and a standby state (range state) is established.

In the surrounding state, the control unit 8 receives the neighboring base station information (Neighbor-List) from the communicating base station by the communication unit 1, and generates a search list for handoff based on the Neighbor-List. Then, handoff processing based on this is performed.
Specifically, in a state where communication with the current base station is possible as a standby, the hand-off necessity determination is performed with reference to the search list every predetermined period. In particular, when generating a search list, among the PN code groups notified in the Neighbor-List, the PN code that matches the first frequency band currently in use is placed at the top (that is, the band class is different). A list in which PNs belonging to the second frequency band (primary and secondary frequencies) are positioned at the lower level. As a result, in intermittent handoff determination, first, the pilot signal strength of the upper PN code is measured, and if there is a PN code that can obtain good pilot signal strength, this is handled. Perform a soft handoff to the base station. If there is no PN code capable of soft handoff, a search is performed for the remaining lower PN code, that is, a PN code in which a second frequency band different from the first frequency band currently in use is designated, When the determination is made and the hard handoff is possible, the frequency of the communication unit 1 is switched from the currently used frequency to search the channel, and the hard handoff process is executed.

  Further, the control unit 8 stores, in the storage unit 7, information related to the communication system (frequency band) captured via the communication unit 1 in the range state (standby state). That is, when any communication system can be acquired, the control unit 8 stores the communication system as an acquisition history (MRU: Most Recently Used: corresponding to acquisition history information of the present invention). The MRU includes not only information regarding the latest one communication system successfully acquired as acquisition history but also information (band class / frequency, primary / secondary) for specifying a plurality of communication systems by FIFO. Channel identifier, protocol identifier, used channel identification code, etc.) are stored in the order of successful acquisition.

A specific example of the MRU that is the acquisition history information of the communication system acquired in the past and stored in the storage unit 7 in this embodiment is shown in FIG.
FIG. 3 is a diagram illustrating an example of the MRU.
As shown in FIG. 3, in this embodiment, for example, the MRU is No. , Mode, Bandclass, Channel, Iprior.
No. Is the number of the communication system stored in the MRU, and the communication system captured more recently has a smaller number.
Mode indicates a communication system with the communication system. HDR (High Data Rate) is one of communication methods.
Channel indicates a channel of the communication system.
Iprior is an index indicating the priority of the communication system at the time of out-of-service call transmission processing described later, and is an integer value. Iprior is determined according to the length of time that the mobile phone 100 is communicating via the communication unit 1. Note that Iprior corresponds to the acquisition time information of the present invention.

Hereinafter, a method for determining the Iprior of the control unit 8 will be described.
FIG. 4 is a flowchart for explaining an Iprior determination method of the control unit 8.
Step ST1:
If any communication system is captured via the communication unit 1, the process proceeds to step ST2, and if not, step ST1 is repeated.
Step ST2:
The control unit 8 starts a timer Tprior that measures the time since the system was captured.

Step ST3:
If the timer Tprior started in step ST2 reaches a predetermined threshold after a predetermined time has passed, the process proceeds to step ST4, and if not, step ST3 is repeated. Here, the predetermined threshold is, for example, a threshold set in advance at the time of shipment of the mobile phone 100 and stored in the storage unit 7 and corresponds to the first threshold of the present invention.
Step ST4:
Since the timer Tprior has reached a predetermined value in step ST3, the control unit 8 increments the counter Iprior of the communication system captured in step ST1 by one.

Step ST5:
If communication with the communication system captured in step ST1 is interrupted and the communication is out of service, the process proceeds to step ST7, and if communication is continued, the process proceeds to step ST6.
Step ST6:
The control unit 8 resets and restarts the timer Tprior, and returns to step ST3.
Step ST7:
The control unit 8 stops the timer Tprior and returns to step ST1.

  As described above, the counter Iprior is a value that is incremented by 1 when a certain communication system is captured, the time after entering the range is measured by the timer Tprior, and the timer Tprior reaches a predetermined value. . That is, the value of the counter Iprior increases as the time during which the communication system is captured via the communication unit 1 is longer. On the other hand, if it determines with having shifted to the out-of-service state from the in-service state, the control unit 8 starts a timer and measures an elapsed time Tpass from the out-of-service transfer.

In addition, the control unit 8 makes an outgoing call request for communication with the outside when the user is out of service area (a state where no communication system is captured and the service area return process is activated), for example, by an operation via the user operation unit 2 or the like. If requested, out-of-service transmission processing is performed.
Hereinafter, the out-of-service calling process will be described in detail.
FIG. 5 is a flowchart for explaining the operation of the mobile phone 100 during out-of-service call processing.

Step ST11:
A transmission request is made from a client (application or the like) by a user operation or the like via the operation unit 2 or the like.
Step ST12:
The control unit 8 compares the elapsed time Tpass from the time of out-of-range transition with a plurality of predetermined threshold values THphase (i) (i is a natural number) and means how much the current time has elapsed from the time of out-of-range transition. Determine the phase to be performed.
The plurality of predetermined threshold values THphase (i) are threshold values that are determined in advance and stored in, for example, the storage unit 7 in order to determine how much time has elapsed since the time of out-of-service transition.
Phase 1 if Tpass <THphase (1)
Phase 2 if THphase (1) ≦ Tpass <THphase (2)
If THphase (2) ≦ Tpass <THphase (3) Phase 3,
Phase 4 when THphase (3) ≦ Tpass <THphase (4)
...
If Tpass is equal to or greater than THphase (i) and less than THphase (i + 1), the phase is determined as i.
The value of each THphase (i) may be determined in advance when the mobile phone 100 is shipped, for example, and stored in the storage unit 7.

Step ST13:
The control unit 8 is an MRU No. The value of the counter Iprior of the communication system of j (j is a natural number, but the initial value is 1) is compared with the threshold value THprior (i) corresponding to the phase determined in step ST12, and Iprior ≧ THprior (i) If so, the process proceeds to step ST14. If Iprior <THprior (i), the process proceeds to step ST17.
THprior (i) is a threshold value set in advance for each phase i, and takes a larger value as the phase is larger.
Step ST14:
The control unit 8 is an MRU No. scan j communication systems.

Step ST15:
As a result of the scan performed in step ST14, the control unit 8 proceeds to step ST16 if acquisition of the communication system is successful, and proceeds to step ST17 if it fails.
Step ST16:
The control unit 8 performs transmission processing for the communication system that has been successfully captured. Thereafter, until the out-of-service state is entered again, the in-service state is entered, and the control unit 8 executes standby processing.

Step ST17:
The control unit 8 adds 1 to j.
Step ST18:
The control unit 8 determines that j is the lowest number in the MRU. In other words, when the scanning is completed for all communication systems in the MRU, the process proceeds to step ST19, where j is the lowest number in the MRU. If it is as follows, that is, if the scanning has not been completed for all communication systems of the MRU, the process returns to step ST13.
In this way, the control unit 8 performs a scan for the communication system in the MRU until the communication system is successfully acquired.

Step ST19:
The control unit 8 scans the PRL k-th (k is a natural number) communication system stored in advance in the storage unit 7. The PRL is a list in which priorities of communication systems that can be captured are determined in advance, and corresponds to the reference priority information of the present invention.
Step ST20:
As a result of the scan performed in step ST19, the control unit 8 proceeds to step ST21 if acquisition of the communication system is successful, and proceeds to step ST22 if it fails.

Step ST21:
The control unit 8 performs transmission processing for the communication system that has been successfully captured. Thereafter, until the out-of-service state is entered again, the in-service state is entered, and the control unit 8 executes standby processing.
Step ST22:
The control unit 8 adds 1 to k.

Step ST23:
When k exceeds the number of communication systems in the PRL, that is, when scanning for all communication systems in the PRL is completed, the control unit 8 proceeds to step ST24, where k is the number of communication systems in the PRL. If it is as follows, that is, if the scan has not been completed for all communication systems of PRL, the process returns to step ST19.
As described above, the control unit 8 performs a scan for the communication system in the PRL until the communication system is successfully acquired.
Step ST24:
The control unit 8 determines that the out-of-service call processing has failed, and ends the out-of-service call processing.

As described above, in the mobile phone 100 of the present embodiment, first, each communication system in the MRU is scanned, and if the communication system in the MRU cannot be captured, the communication system described in the PRL. Scan in the order listed. When the communication systems described in the PRL are scanned in the order of the list, the scanning is not performed on the communication systems that have already been scanned in the MRU (the list is skipped and the next communication system is scanned). May be performed). In this way, it is possible to reduce the overall time required for scanning during out-of-service call processing.
However, the mobile phone 100 according to the present embodiment is characterized in that, when each communication system in the MRU is scanned during out-of-service call processing, the phase i is determined in step ST12 and the communication is performed in the service area state (standby state) in step ST13. Whether or not to scan the communication system is compared by comparing the value Iprior determined for each system and stored in association with the MRU in the storage unit 7 with the threshold value THprior (i) corresponding to the phase i. There is a place to decide.

Hereinafter, specific examples of phase i and THprior (i) will be shown.
When the out-of-service transmission process is performed immediately after phase 1, that is, immediately after the out-of-service transition, specifically, when Tpass described in step ST12 is small and smaller than THphase (1), THprior (1) is assumed to be 0.
When the out-of-service call processing is performed after a predetermined time after the out-of-service transition, specifically, when Tpass described in step ST12 is equal to or higher than THphase (1) and smaller than THphase (2), THprior (2 ) Is 2.
When the out-of-service transmission process is performed in phase 3, that is, after the elapse of a predetermined time after the out-of-service transition, specifically, when Tpass described in step ST12 is greater than or equal to THphase (2) and smaller than THphase (3), ) Is 4.

Here, the determination of whether or not to perform scanning when the above-described specific example of phase i and THprior (i) is applied to each communication system shown in the specific example of the MRU shown in FIG. 3 will be described.
As shown in FIG. The Iprior of the communication system 1 is 2, 2 is 0, No. 2 No. 3 Iprior is 3, No. 3 Iprior of 4 is 1.
If it is determined in step ST12 in the flowchart of FIG. 5 that the phase is 1, in step ST13, THprior (1) is 0 as described above, so that all communication systems satisfy Iprior ≧ THprior (1). That is, all communication systems will be scanned. That is, THprior (1) corresponds to the second threshold value of the present invention.

Further, when it is determined in step ST12 in the flowchart of FIG. 5 that the phase is 2, in step ST13, THprior (2) is 2, as described above, and thus a communication system satisfying Iprior ≧ THprior (2). No. 1 and no. 3 and no. 1 and no. 3 is scanned and no. 2 and no. The communication system 4 will not be scanned.
If it is determined in step ST12 in the flowchart of FIG. 5 that the phase is 3, in step ST13, THprior (3) is 4, as described above, and therefore all communication systems have Iprior <THprior (3 That is, all communication systems are not scanned. In this case, in the out-of-service call processing, the communication system in the MRU is not scanned at all, and the communication system in the PRL is scanned.

As described above, according to the mobile phone 100 of the present embodiment, during the out-of-service call processing, when scanning each communication system in the MRU, the phase i is determined according to the elapsed time from the out-of-service transition, The index Iprior determined for each communication system and stored in the MRU of the storage unit 7 according to the time when the communication system in the surrounding state (standby state) was captured, and the threshold value THprior (i) according to the phase i To determine whether to scan the communication system.
That is, according to the mobile phone 100 of the present embodiment, the elapsed time from the out-of-range transition is classified stepwise as “phase”, and when the phase is small, that is, the elapsed time from the out-of-range transition is short, the MRU When a large number of communication systems are scanned and the phase is large, that is, when the elapsed time from the out-of-service transition is long, the number of communication systems to be scanned is decreased according to the phase. For this reason, when the time from the out-of-service transition is long and the possibility of capturing the communication system in the MRU is low, the number of communication systems that perform scanning according to the MRU can be reduced, and the out-of-service transmission processing time can be reduced. The power consumption required for out-of-service call processing can be saved.
In addition, according to the mobile phone 100 of the present embodiment, first, each communication system in the MRU is scanned, and if the communication system in the MRU cannot be captured, the communication systems described in the PRL are listed. Scanning is performed in order, but when scanning the communication systems described in the PRL in the order of the list, the scanning is not performed on the communication system that has already been scanned in the MRU (the list is skipped and the next communication is performed). Therefore, it is possible to reduce the overall time required for scanning during out-of-service call processing.

The present invention is not limited to the embodiment described above.
That is, when implementing the present invention, various modifications, combinations, sub-combinations, and alternatives may be made to the components of the above-described embodiments within the technical scope of the present invention or an equivalent scope thereof.

FIG. 1 is a block diagram showing an internal configuration of a mobile phone. FIG. 2 is a diagram illustrating an example of the appearance of a mobile phone. FIG. 3 is a diagram illustrating an example of the MRU. FIG. 4 is a flowchart for explaining an Iprior determination method of the control unit. FIG. 5 is a flowchart for explaining the operation at the time of out-of-service call processing of the mobile phone.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Mobile phone, 101 ... Upper housing | casing, 102 ... Lower housing | casing, 103 ... Hinge part, 1 ... Communication part, 2 ... Operation part, 3 ... Sound processing part, 4 ... Speaker, 5 ... Microphone, 6 ... Display part 7, storage unit, 8 ... control unit

Claims (6)

A wireless communication terminal that performs wireless communication with a plurality of base stations,
A communication unit that performs wireless communication by selecting one of a plurality of communication systems;
A control unit for switching communication systems used by the communication unit to perform communication by wireless communication;
A storage unit capable of storing information related to a plurality of communications;
Have
The controller is
Information related to a communication system that has been successfully acquired among the plurality of communication systems at the time of the local time is stored in the storage unit as acquisition history information including acquisition time information that is information related to the acquisition time,
When a call is requested in an out-of-service state, among the communication systems in the acquisition history information stored in the storage unit, the communication unit tries the acquisition in order from the communication system with the longer acquisition time, and the acquisition succeeds. A wireless communication terminal that performs communication connection processing on a communication system. The time information measures the time during which the control unit has captured the communication system corresponding to the time information in the area, and increments by 1 when the measured time reaches a first predetermined threshold value. The wireless communication terminal according to claim 1, wherein the wireless communication terminal is an integer value. When the control unit detects a transition to the outside of the service area, the control unit measures the elapsed time from the out-of-service transition, and causes the communication unit to perform a capture attempt according to the length of the elapsed time. The wireless communication terminal according to claim 1, wherein the wireless communication terminal is determined. When the elapsed time is smaller than a second predetermined threshold, the control unit causes the communication unit to perform acquisition attempts for all communication systems in the acquisition history information, and the elapsed time Is equal to or greater than a second predetermined threshold value, the communication unit in the acquisition history information in which the communication unit attempts acquisition every time the elapsed time exceeds a plurality of predetermined threshold values. The wireless communication terminal according to any one of claims 1 to 3, wherein the number is decreased until the number becomes zero. The storage unit stores reference priority information related to a priority when performing a capture attempt for the plurality of communication systems,
When acquisition is not successful for all communication systems in the acquisition history information, the control unit causes the communication unit to attempt acquisition of the communication system according to the priority of the reference priority information. The wireless communication terminal according to claim 1, wherein the wireless communication terminal is a wireless communication terminal. When the control unit causes the communication unit to attempt acquisition of the communication system in accordance with the priority order of the reference priority information, the control unit has already made the communication unit try to acquire the communication system in the acquisition history information. The radio communication terminal according to claim 1, wherein no attempt is made to capture.

Images