JP2010035215A - Wireless communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless communication terminal, in which unexpected communication interruption does not occur during data communication, the wireless communication terminal being configured to perform communication while switching two communication schemes using a common antenna. <P>SOLUTION: A wireless communication terminal includes a measuring means for measuring quality of a signal transmitted by a base station 100 and a system control means for carrying out a handoff during waiting on the basis of quality of signals transmitted from a waiting base station and another base station. The system control means determines whether a first communication scheme is under communication. When the first communication scheme is under communication, if the wireless communication terminal fails prescribed times in acquiring the signal received from the waiting base station 100, a handoff during waiting in the second communication scheme is carried out. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wireless communication terminal, a handoff execution method, and a handoff execution program that perform communication by switching between two communication methods using a common antenna.

2. Description of the Related Art Dual type wireless communication terminals that can communicate with a base station by switching between two communication methods are known.
In a dual wireless communication terminal, by switching between two communication methods using a common antenna, the wireless communication state of the other communication method is measured during communication using one communication method, and the incoming call is monitored. What can be done is specifically referred to herein as a hybrid system.

JP 2003-298762 A

In the hybrid wireless communication terminal as described above, particularly in the hybrid wireless communication terminal of the cdma2000 1x system mainly for voice communication and the 1xEVDO system dedicated to data communication, the 1xEVDO system is performing data communication. In order to monitor the incoming cdma2000 1x, the data communication of 1xEVDO is suspended at a predetermined interval (for example, 5.12 seconds), the antenna and the radio unit are switched to cdma2000 1x, and the incoming call is monitored by cdma2000 1x. .
When the incoming call monitoring process ends, the antenna and the radio unit are switched to 1xEVDO again, and data communication in the 1xEVDO system is resumed.

Here, the area where the wireless communication terminal exists is a cdma2000 1x system near the boundary of the service area of a plurality of base stations (when the reception quality (for example, RSSI value) of the signals from the plurality of base stations) competes) In this case, the cdma2000 1x system may frequently repeat idle handoff (handoff in a standby state).
Under this situation, in order to monitor incoming cdma2000 1x, the cdma2000 1x system is switched from the 1xEVDO system to the cdma2000 1x system at the predetermined interval described above, and the system monitoring process of cdma2000 1x is performed.
At this time, when idle handoff of the cdma2000 1x system is detected and further idle handoff is detected after the idle handoff processing, the antenna unit and the radio unit of the wireless communication terminal remain occupied by the cdma2000 1x system. End up. When this occupation takes a certain time, the 1xEVDO system determines that the radio wave is interrupted and performs data communication interruption processing.

  That is, during 1xEVDO data communication, regardless of the radio wave condition of the 1xEVDO system, data communication of the 1xEVDO system is disconnected due to repeated idle handoff in the cdma2000 1x system.

  The present invention has been made in view of such problems. In a hybrid communication terminal that switches between the cdma2000 1x system and the 1xEVDO system to communicate with a base station, the cdma2000 1x system side frequently idles. An object of the present invention is to provide a wireless communication terminal and a handoff execution program in which an unexpected communication interruption does not occur during data communication on the 1xEVDO system side even in a radio wave state in which handoff is repeated.

  The present invention relates to a standby base station and other base stations in a wireless communication terminal capable of performing wireless communication with a base station using a common antenna for the first communication system and the second communication system, and capable of waiting in both communication systems. A system control means for executing a handoff during standby when a difference in quality of signals transmitted from each of the stations exceeds a predetermined threshold; and a movement detection means for detecting a movement state of the wireless communication terminal, The system control means determines whether or not the first communication method is communicating. When the first communication method is communicating, the second control method is based on the detection result of the movement detecting means. The threshold value of the handoff during standby in the communication method is variable.

  According to the present invention, during the communication in the first communication method, the frequency of handoff in the second communication method can be reduced, so that it is difficult for unexpected data communication to be interrupted in the first communication method, It is possible to perform stable data communication and improve data communication throughput.

It is a block diagram showing the structure of the wireless communication terminal 200 of embodiment of this invention. It is explanatory drawing which shows the state of RF control part 40 at the time of standby. It is explanatory drawing which shows the state of RF control part 40 when handoff generate | occur | produces in 1x system. It is explanatory drawing which shows the state of RF control part 40 at the time of 1x system performing standby processing during DO system communication. It is explanatory drawing which shows the state of RF control part 40 when handoff generate | occur | produces in 1x system during DO system communication. It is a flowchart which shows a handoff process. It is a flowchart which shows a normal mode handoff process. It is a flowchart which shows a movement mode handoff process. It is a flowchart which shows a fixed mode handoff process.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a wireless communication terminal according to an embodiment of the present invention.

  Wireless communication terminal (mobile phone terminal) 200 according to the present embodiment uses cdma20001x communication method (hereinafter referred to as “lx system”) and 1xEVDO communication method (hereinafter referred to as “DO system”) using common antenna 10. The wireless communication terminal can communicate while moving by performing handoff between the base station 100A and the base station 100B.

  The antenna 10 converts a high-frequency signal from either the 1xRF unit 20 or the DO RF unit 30 into a radio wave and transmits the radio wave to the base stations 100A and 100B, and receives a radio wave from the base stations 100A and 100B and receives the 1xRF unit 20 Alternatively, it is sent to the DO RF unit 30 as a high frequency signal.

The 1xRF unit 20 converts data or a voice signal to be transmitted in the 1x system into a high-frequency signal and sends it to the antenna 10.
Moreover, the high frequency signal sent from the antenna 10 is converted into a data signal or an audio signal.

The DO RF unit 30 converts data to be transmitted by the DO system into a high-frequency signal and sends it to the antenna 10.
Moreover, the high frequency signal sent from the antenna 10 is converted into a data signal.

The RF control unit 40 is a control unit that controls communication between the two systems of the DO system and the 1x system.
Further, the RF control unit 40 measures the intensity (RSSI) of radio waves from the base station 100 received by the antenna 10.

The system control unit (system control unit) 50 is a control unit that controls each unit of the wireless communication terminal 200 in an integrated manner.
The system control unit 50 controls the RF control unit 40 to control switching between the two systems of the DO system and the 1x system.
In particular, during standby, the two communication systems are selectively switched at predetermined time intervals to wait for an incoming call in both communication systems.
In the 1x system, it is determined whether or not to perform handoff based on the radio wave condition of the base station received by the antenna 10 when waiting for an incoming call, and handoff processing is executed when it is determined that it is necessary.
In this specification, the operation of switching the connected base station is called handoff.
Also, based on the position information measured by the GPS unit 70, it is determined whether or not the terminal is moving.

  The system storage unit 60 is configured by a memory such as a RAM, and stores applications, temporary data, and the like.

  A GPS (Global Positioning System) unit 70 receives radio waves from a plurality of GPS satellites, and measures the position of the wireless communication terminal 200 using arrival time differences between the received radio waves.

  The UI unit 80 serves as an interface with a user who operates the wireless communication terminal 200. The UI unit 80 is an LCD display (main display, sub-display) that displays characters, images, and the like, a speaker that outputs sounds, and inputs sound. It consists of a microphone, input keys for receiving user input, and the like.

The open / close detection unit 90 detects the open / closed state of the wireless communication terminal 200.
The wireless communication terminal 200 of the present embodiment has a so-called folder type structure in which two housings are connected so as to be openable and closable.
When the wireless communication terminal 200 is opened, the display on the display provided in the housing can be confirmed, and a voice call can be performed using the microphone and the speaker provided in the housing.
On the other hand, when the wireless communication terminal 200 is closed, the casing is folded and the display is hidden and the display cannot be confirmed, and the microphone and the speaker are also hidden and the voice call cannot be performed.
The open / close detection unit 90 detects the state (open and closed) of the housing and sends the detection result to the system control unit 50.

  Note that the open / close detection unit 90 may detect the expansion / contraction state of the antenna instead of the open / close state of the housing.

  Next, the operation of the wireless communication terminal according to the embodiment of the present invention will be described.

  In the wireless communication terminal 200 according to the embodiment of the present invention, one RF control unit 40 is shared by the 1x system and the DO system, and the communication side monopolizes the RF control unit 40.

  FIG. 2 is an explanatory diagram illustrating a state of the RF control unit 40 when the wireless communication terminal 200 is on standby.

Each of the 1x system and the DO system performs a standby process for detecting a pilot signal as to whether there is an incoming call at every predetermined timing (5.12 seconds in this embodiment). The operation of the RF control unit 40 is “Active”.
Since the RF control unit 40 is monopolized while the standby process is performed in one system, the two systems perform the standby process at different timings.

  FIG. 3 is an explanatory diagram illustrating a state of the RF control unit 40 when a handoff (idle handoff) occurs in the 1x system during standby processing.

The wireless communication terminal 200 compares the state of radio waves with the currently communicating base station with the one with the best radio wave condition among other base stations, and the difference between the radio wave states of the two sets a predetermined threshold value. If it exceeds, handoff is performed to the other base station.
The handoff process (normal mode handoff process) at this time will be described later with reference to FIG.

FIG. 3 shows a case where handoff is performed in the 1x system when both the 1x system and the DO system are performing standby processing.
Since the timing of performing the standby process differs for each base station, when the handoff is performed and the communication destination is changed to another base station, the timing of the standby process is changed.
At this time, on the DO system side, in response to the change of the standby timing on the 1x system side, the standby timing is changed so as not to overlap with the standby timing of the 1x system.
The standby timing is changed by exchanging a predetermined message between the radio communication terminal 200 and the base station.

  FIG. 4 is an explanatory diagram illustrating a state of the RF control unit 40 when the 1x system performs standby processing while the DO system is communicating.

When the DO system performs communication (data communication) and the standby processing timing of the 1x system comes, the RF control unit 40 is temporarily switched to the 1x system side.
When the standby process ends, the RF control unit 40 is switched to the DO system side again.

  FIG. 5 is an explanatory diagram illustrating a state of the RF control unit 40 when a handoff occurs in the 1x system performing the standby process while the DO system is communicating.

As described in FIG. 4, even when the DO system is communicating, the 1x system performs standby processing at predetermined intervals.
When a 1x system handoff is detected during the standby process, first, a handoff process is performed with the base station 100.
During this handoff process, the RF controller 40 is monopolized by the 1x system.
When the handoff process ends, the RF control unit 40 is switched to the DO system side again, and communication is resumed.

At this time, if further handoff processing is detected immediately after the handoff of the 1x system, the RF control unit 40 of the wireless communication terminal remains monopolized by the 1x system.
During the handoff process of the 1x system, the DO system cannot communicate.
In the DO system, it is set in advance to perform communication interruption processing when communication interruption continues for a predetermined time.
Therefore, if the RF unit 40 is monopolized by the handoff process in the 1x system and the DO system cannot communicate, a certain period of time elapses, and the DO system performs a communication interruption process.

  Therefore, as described below, wireless communication terminal 200 according to the embodiment of the present invention determines whether or not communication is being performed in the DO system, and if data communication is being performed, the frequency of occurrence of handoff of 1x system In addition, it is determined whether or not the wireless communication terminal 200 is moving. If the wireless communication terminal 200 is not moving and is fixed, processing for minimizing the frequency of handoff occurrence of the 1x system is performed.

  FIG. 6 is a flowchart showing the handoff process, and the following process is performed by the system control unit 50.

First, it is determined whether data communication is being performed in the DO system (step 1001).
When it is determined that the DO system is not in data communication, normal mode handoff processing (FIG. 7) is performed.
If it is determined that the DO system is in data communication, it is next determined whether the current mode is “movement mode” or “fixed mode” (step 1002).

  When the wireless communication terminal 200 is currently moving, it is determined as “movement mode”, and when the wireless communication terminal 200 is not moving (movement range or movement speed is extremely small), it is determined as “fixed mode”.

The determination of the movement mode and the fixed mode is performed based on the current position of the wireless communication terminal 200 acquired by the GPS unit 70 during a predetermined period.
When the moving distance in a predetermined period exceeds a predetermined distance (for example, when moving for 100 m or more per 10 minutes), the moving mode is determined. Otherwise, the “fixed mode” is determined. .

Further, the movement mode or the fixed mode may be determined according to the open / closed state of the housing detected by the open / close detection unit 90.
For example, when the wireless communication terminal 200 is fixed and a streaming video or the like is viewed, the user opens the casing so that the display on the main display can be confirmed, and, for example, moves while downloading data or the like. In such a case, it is conceivable that the user closes the casing in order to put the wireless communication terminal 200 in a pocket or bag.
Therefore, during the data communication by the DO system, the “fixed mode” may be determined when the casing is opened, and the “movement mode” may be determined when the casing is closed.

In addition, the open / close detection unit 90 may detect the expansion / contraction state of the antenna. In this case, for example, when the antenna is extended, the wireless communication terminal 200 may be fixed and the streaming video may be viewed. Therefore, it can be determined that there is a high possibility that the user is moving with the wireless communication terminal 200 in a pocket or bag when the antenna is retracted.
Accordingly, the “fixed mode” may be determined when the antenna is in the “extended” state, and the “moving mode” may be determined when the antenna is in the “contracted” state.

Furthermore, another example is conceivable as the determination of the above-described opening / closing detection unit 90.
For example, as described above, the wireless communication terminal 200 according to the present embodiment can perform a voice call (voice call based on the 1x system) only with the casing opened, and can perform a voice call with the casing closed. Is not done.
For this reason, during the data communication by the DO system, since the voice call cannot be performed when the case is closed, it is determined that the priority of the 1x system is low, and the frequency of handoff is kept low. The determination may be made as “fixed mode”.
Similarly, even when the open / close detection unit 90 detects the expansion / contraction state of the antenna, there is a high possibility that a voice call is performed when the antenna is extended, and there is a possibility that a voice call is not performed when the antenna is contracted. It can be judged that it is expensive.
For this reason, when the antenna is in the “extended” state, it may be determined as “moving mode”, and when the antenna is in the “down” state, it may be determined as “fixed mode”.
Further, the system control unit 50 may determine the movement mode or the fixed mode by an application currently running on the wireless communication terminal 200.
Specifically, if an application that is mainly used while moving is operating, it is determined as “move mode”, and if an application that is mainly used is operating, it is determined as “fixed mode”. judge.
An example of an application that is mainly used while moving is a “map display application”, and an application that is mainly used in a fixed manner is a “media player” that receives and browses stream video.

  As described above, the GPS unit 70, the open / close detection unit 90, and the system control unit 50 detect the movement state of the wireless communication terminal 200 as movement detection means.

  If it is determined in step 1002 that the movement mode is selected, the process proceeds to a movement mode handoff process (step 1003, FIG. 8). If it is determined that the mode is a fixed mode, the process proceeds to a fixed mode handoff process (step 1004, FIG. 9).

In the movement mode, there is a high possibility that a handoff will occur in the 1x system, but control is performed so as to reduce the frequency of handoff so that data communication is not disconnected in the DO system.
On the other hand, in the fixed mode, since the terminal is not moving (or the casing is closed and the priority of the voice call is low), control is performed so that handoff does not occur as much as possible.

  FIG. 7 is a flowchart showing normal mode handoff processing, which is performed by the system control unit 50.

  “Normal mode” is processing when communication is not performed in the DO system.

First, the pilot signal strength (RSSI value) from the base station is acquired (step 4001).
At this time, the pilot signal strength of the currently communicating base station is “AP”, and the other base station with the highest pilot signal strength is “NP”.

Next, it is determined whether or not the difference between the two acquired pilot signal strengths exceeds a predetermined threshold (step 4002).
Specifically, whether or not the value obtained by subtracting the current base station pilot signal strength “AP” from the pilot signal strength “NP” of another base station exceeds a preset handoff determination threshold “A” Determine whether.

If it is determined that the difference between the two acquired pilot signal strengths does not exceed the predetermined threshold, the process returns to step 4001 to repeat this process.
When it is determined that the difference between the two acquired pilot signal strengths exceeds a predetermined threshold value, handoff is performed to a base station different from the currently communicating base station (step 4003).

  FIG. 8 is a flowchart showing the movement mode handoff process, which is performed by the system control unit 50.

First, the pilot signal strength (RSSI value) from the base station is acquired (step 2001).
At this time, the pilot signal strength with the currently communicating base station is “AP”, and the other pilot station with the highest pilot signal strength is “NP”.

Next, it is determined whether or not the difference between the two acquired pilot signal strengths exceeds a threshold value (A + α) (step 2002).
Specifically, the value obtained by subtracting the pilot signal strength “AP” of the current base station from the pilot signal strength “NP” of the other base station is a predetermined value “ It is determined whether or not the value obtained by adding “α” has been exceeded.

If it is determined that the difference between the two acquired pilot signal strengths does not exceed the predetermined threshold, the process returns to step 2001 to repeat this process.
When it is determined that the difference between the two acquired pilot signal strengths exceeds a predetermined threshold value, handoff is performed to a base station different from the currently communicating base station (step 2003).
That is, the threshold value for handoff determination is set higher than in the normal mode, and the frequency of handoff occurrence is reduced.

  According to the processing of FIG. 8, the threshold value of pilot signal strength for the wireless communication terminal 200 to perform handoff during data communication in the DO system is set higher than in the normal state, so that the frequency of handoff may be reduced. In addition, even during data communication in the DO system, disconnection of data communication due to occurrence of handoff in the 1x system is less likely to occur.

  FIG. 9 is a flowchart showing the fixed mode handoff process, which is performed by the system control unit 50.

First, the pilot signal strength (RSSI value) with the base station is acquired (step 001).
At this time, the pilot signal strength with the currently communicating base station is “AP”, and a base station other than the currently communicating base station with the highest pilot signal strength is “NP”.

Next, it is determined whether or not the pilot signal strength “AP” with the currently communicating base station cannot be received, that is, whether or not the AP signal is lost (step 3002).
If it is determined that the AP is not lost, the process returns to step 3001 to repeat the process.
When it is determined that the AP is lost, the pilot signal strength (AP) with the base station currently communicating again is acquired at the next timing (in this embodiment, after 5.12 seconds), and the acquired AP It is determined again whether or not is lost (step 3003).
If it is determined that the acquired AP is not lost, the process returns to step 3001 to repeat this process.
When it is determined that the acquired AP is lost, that is, when it is determined that the pilot signal strength with the base station is lost twice consecutively, first, a base other than the currently communicating base station It is determined whether the station pilot signal strength (ie, “NP”) is lost.
If it is determined that the NP is not lost, handoff to the other base station is performed (step 3005).
Thereafter, the process returns to the flowchart of FIG.

If it is determined in step 3004 that the NP is lost, the base station (AP) and the other base station (NP) that are currently communicating are both lost, so the communication of the 1x system is lost ( It is determined that communication with the base station has been disconnected (step 3006).
Then, a pilot signal search is performed in order to communicate with a new base station (step 3007).

  According to the processing of FIG. 9, only when it is determined that the communication with the current base station has been lost continuously at two times, handoff is performed to other base stations. The frequency can be reduced, and during data communication in the DO system, disconnection of data communication due to occurrence of handoff of the 1x system is less likely to occur.

As described above, in the embodiment of the present invention, in the wireless communication terminal 200 that is a hybrid terminal having the cdma2000 1x system and the 1xEVDO system, during the data communication by the 1xEVDO system, the handoff occurs as much as possible in the cdma2000 1x system. Control the frequency to be low.
By doing so, a wireless communication terminal exists near the boundary between service areas of a plurality of base stations (when the signal strength (RSS1 value) from the plurality of base stations is antagonizing), and handoff processing in the cdma2000 1x system Even in an environment where frequent occurrence occurs, unexpected interruption of data communication in the 1xEVDO system is unlikely to occur, so that stable data communication can be performed and the throughput of data communication can be improved.

  In the embodiment of the present invention, the pilot signal strength (RSSI value) is used to determine whether or not to perform handoff, but this can be used even if the pilot signal carrier-to-interference wave ratio (C / I value) is used. Good.

  In the embodiment of the present invention, the hybrid system of the cdma2000 1x system and the 1xEVDO system has been described. However, the present invention is not limited to this. Any type of communication method can be used as long as the wireless communication state of the other communication method can be measured at a predetermined timing and the incoming call monitoring can be performed while switching the communication method. .

In the fixed mode handoff process according to the embodiment of the present invention, an example has been described in which handoff is performed when acquisition of a signal transmitted by a standby base station has failed twice in succession. For example, it may be set in advance such as three times, four times, or once.
Furthermore, the failure to acquire the signal transmitted by the standby base station a predetermined number of times is not limited to the case where the failure occurs continuously, and the handoff is executed when the predetermined number of times fails discontinuously within a predetermined reference time. It may be.

  In the embodiment of the present invention, the GPS unit 70 receives radio waves from a plurality of GPS satellites, and measures the position of the wireless communication terminal 200 using the arrival time difference between the received radio waves. However, since the measurement of the actual position requires mathematical calculation and the processing load increases, the GPS unit 70 transmits information on the arrival time difference of the received radio waves from the plurality of GPS satellites to the base station 100, and this information Then, the position of the wireless communication terminal 200 may be measured on the base station 100 side, and the measurement result may be transmitted to the wireless communication terminal 200.

In the embodiment of the present invention, a so-called folder-type wireless communication terminal in which two housings are connected so as to be openable and closable has been described. However, the present invention is not limited to this as long as the wireless communication terminal can be opened and closed. is not.
For example, it may be a so-called flip type in which a protective member capable of covering a part of the casing is connected to the casing so as to be openable and closable, or the two casings are connected to each other so as to be rotatable in the horizontal direction. It may be a horizontal rotation type, or may be a slide type that can be opened and closed by sliding two casings in the vertical direction.

DESCRIPTION OF SYMBOLS 10 Antenna 20 1xRF part 30 DO RF part 40 RF control part 50 System control part 60 System storage part 70 GPS part 80 UI part 90 Opening / closing detection part 100A, 100B Base station 200 Wireless communication terminal (cell-phone terminal)

Claims (1)

In a wireless communication terminal capable of performing wireless communication with a base station using a common antenna for the first communication method and the second communication method, and waiting in both communication methods,
System control means for performing handoff during standby when the difference in quality of signals transmitted from the standby base station and other base stations exceeds a predetermined threshold;
The wireless communication terminal includes movement detection means for detecting a movement state of the wireless communication terminal, and the system control means determines whether or not the first communication method is communicating, and the first communication method is communicating. In some cases, the threshold value of the handoff during standby in the second communication method is varied based on the detection result of the movement detection means.

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