JPH1127719A - Radio communication equipment and handover processing method used for the equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication equipment in which handover can be realized comparatively easily, even during high speed movement and a handover processing method used for the equipment. SOLUTION: In the case that the proposed equipment approaches the border of the coverage of a radio base station that connects to the equipment (301), an other radio base station is retrieved (302), the connection is changed (handed over) (304) from the radio base station currently connected to the other retrieved radio base station. In the case of a high speed moving mode, when other radio base stations for hand-over cannot be retrieved with a 1st time (conventionally 310 msec), the retrieval is continued (302) for a 2nd time without switchback processing (10 sec). Since the retrieval time is markedly increased from the conventional time of 31-msec into 10 sec, handover is realized, even while the equipment is moving at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a PHS (Personal
More particularly, the present invention relates to a wireless telephone device capable of appropriately performing handover even while moving at high speed, and a handover processing method used for the wireless communication device.

[0002]

2. Description of the Related Art In a PHS radio telephone apparatus, a handover for changing a radio base station connected during communication is possible. Thus, for example, even when the caller is walking, communication can be continued without interruption. This handover occurs when the radio telephone device degrades the voice quality during a call (for example, when the bit error rate increases) or when the electric field reception level decreases. By executing a predetermined process, another wireless base station is searched for and communication with the wireless base station is established.

[0003] In a PHS, the size of a zone covered by a radio base station has a radius of 100 m or more.
It is about 200 m. For this reason, in a PHS wireless telephone, handover is performed relatively frequently as the wireless telephone moves.

[0004]

SUMMARY OF THE INVENTION However, PHS
In, each radio base station intermittently transmits broadcast information using a control carrier, so that the broadcast period of broadcast information is relatively long. Furthermore, since the frame synchronization between the wireless base stations does not match, the time from starting the handover process to receiving the notification information from another wireless base station becomes longer. Therefore, the PHS has a problem in that it is not possible to quickly select a radio base station candidate, and it is impossible to realize a handover at high speed.

[0005] For this reason, in the conventional PHS radio telephone device, if a radio base station cannot be acquired by searching another radio base station for a certain time (for example, about 310 ms), the radio base station cannot be acquired. Along with issuing an alarm sound indicating that the user is out of the service area of the station and performing a so-called switchback to establish communication with the original wireless base station, maintain communication with the original wireless base station. Seeking to.

[0006] Due to the handover process and switchback described above, the conventional PHS radio telephone device cannot perform handover while moving at high speed in a car or train, and can do so while walking. It's just that.

[0007] Japanese Patent Application Laid-Open No. 7-284141 discloses that
Although a handover method in a microcell system such as PHS is disclosed, this is a process when a wireless base station can be captured, and does not disclose a case where a wireless base station cannot be captured.

[0008] Japanese Patent Application Laid-Open No. 8-154269 discloses that
Although a mobile communication system that can reliably perform handover even during high-speed movement is disclosed, a handover processing function must be provided in a base station controller that controls a base station, and the PHS must notify the detected frequency. . Such systems are complex and expensive, and are expected to present various difficulties in implementation. Without such disadvantages,
A simple and effective handover method has been demanded.
The handover method is described in Japanese Patent Application Laid-Open No. 8-294158.
This is also disclosed in the official gazette.

[0009] The object of the present invention is to provide a high speed
It is an object of the present invention to provide a wireless communication device that can implement handover and that is relatively easy to implement, and a handover processing method used for the device.

[0010]

A wireless communication apparatus according to the present invention is a wireless communication apparatus that communicates with another communication apparatus by transmitting and receiving a signal via a wireless base station. An operation mode setting switch for setting a mode, search means for searching for another wireless base station when approaching the boundary of the coverage area of the connected wireless base station, and searching for the connected wireless base station. Handover means for changing the connection to the other radio base station, and switching back to the connected radio base station when the other radio base station is not searched by the search means. Means,
When the high-speed movement mode is set by the operation mode setting switch, when the search means cannot search for another wireless base station capable of executing handover at the first time, the switch-back means is operated. And a control unit for controlling the search means and the reverting means so as to execute the search at a second time.

[0011] A handover processing method for a wireless communication device according to the present invention includes: an operation mode setting step of setting an operation mode of the wireless communication device in advance; A search step of searching for another wireless base station, a connection changing step of changing the connection from the connected wireless base station to the searched other wireless base station, and the other wireless base station A switchback step of executing a switchback to the connected radio base station when the search is not performed, and when the operation mode is set to the high-speed movement mode, the search step includes When a search for another wireless base station that can perform handover cannot be performed, the search is performed at a second time without performing the switchback step.

According to the present invention, the operation mode of the wireless communication device is set as desired by the caller according to the use situation, for example, whether the caller is walking or moving at high speed. This makes it possible to appropriately implement handover as the case may be.

The wireless communication apparatus according to the present invention is characterized in that
Is continuous with the first time and is longer than the first time.

For example, according to the PHS standard, it is conceivable to set the time for search to 310 milliseconds and the time for switchback to 10 seconds.

[0015] In the wireless communication apparatus according to the present invention, the control unit causes the reverting means to execute reverting at a third time after the second time.

A wireless communication apparatus according to the present invention is a wireless communication apparatus that communicates with another communication apparatus by transmitting / receiving a signal via a wireless base station, wherein a boundary of a coverage area of the connected wireless base station. When approaching, the search means for searching for another wireless base station, handover means for changing the connection from the connected wireless base station to the searched other wireless base station, and the search means A switching unit for performing a switch back to the connected wireless base station when another wireless base station is not searched; a switchback by the switch unit; and another wireless base station by the search unit. And a control unit that controls the search unit and the return unit so that the search is performed alternately.

The handover processing method for a wireless communication device according to the present invention includes an operation mode setting step of setting an operation mode of the wireless communication device in advance, and a step of: A search step of searching for another wireless base station, a connection changing step of changing the connection from the connected wireless base station to the searched other wireless base station, and the other wireless base station A switchback step of executing a switchback to the connected radio base station when the search is not performed, and when the operation mode is set to the high-speed movement mode, the search step includes When a search for another wireless base station that can perform handover cannot be performed, the search is performed at a second time without performing the switchback step.

According to the present invention, when a situation such as a deterioration in sound quality or a decrease in reception intensity changes, a search for a radio base station for handover and a radio base station to be switched back are performed at predetermined time intervals. Since station search is performed alternately,
It is possible to increase the possibility that communication with any of the wireless base stations will be established. This makes it possible to increase the possibility of performing handover in various usage situations, for example, not only during low-speed movement such as walking, but also during high-speed movement, without having to set the operation mode. Become. Note that the search time is preferably at least as long as mutual communication with another wireless base station can be realized.

A wireless communication apparatus according to the present invention is a wireless communication apparatus which communicates with another communication apparatus by transmitting / receiving a signal via a wireless base station, wherein the boundary of the coverage area of the connected wireless base station. When approaching, the search means for searching for another wireless base station, handover means for changing the connection from the connected wireless base station to the searched other wireless base station, and the search means When another wireless base station is not found, a switchback unit that performs a switchback to the connected wireless base station, and when a predetermined operation is performed, without operating the switchback unit And a control unit that controls the search unit and the return unit so that the search unit searches for another wireless base station.

A handover processing method for a wireless communication apparatus according to the present invention, comprising: a search step of searching for another wireless base station when approaching a boundary of a coverage area of a connected wireless base station; From the middle radio base station, a search step of changing the connection to the searched other radio base station, and if no other radio base station is searched by the search step, to the connected radio base station And a reverting step for executing a reverting step, wherein when a predetermined operation is performed, the retrieving step is performed without performing the reverting step.

According to the present invention, in response to a predetermined instruction,
Since the search for another wireless base station is continued without executing the fallback, the possibility of finding another wireless base station can be increased, and the possibility of handover can be improved. In particular, when the caller is moving at high speed and cannot return to the coverage area of the original wireless base station, the search for the wireless base station is continued without switching back according to the situation at that time. Thus, handover can be more reliably realized. For example, even when the moving speed of the caller increases during a call, handover can be appropriately realized. This instruction may be made to respond to a key operation, for example.

In the wireless communication apparatus according to the present invention, the control unit notifies execution of switchback and activates the switchback unit when a predetermined switch is pressed during the notification. Without causing the search unit to search for another wireless base station.

According to the present invention, the user can select a desired operation mode after knowing the situation of the return.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 of the Invention Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing a configuration of the wireless communication device according to the first embodiment of the present invention. This wireless telephone device (communication device) is the same as a normal PHS wireless telephone device except for the processing executed by the control device 42.

As shown in FIG. 1, this wireless telephone device 10
Is an antenna 12, a switch 1 for switching between transmission and reception
3, RF (Radio Frequency) amplifier 14, multiplier 16,
Frequency synthesizer 18, band pass filter (BP
F) 20, second multiplier 22, local oscillator 24, demodulator 26, TDMA 28, audio codec 30, modulator 32, third multiplier 34, second bandpass filter 3
6 and a power amplifier 40. Further, the wireless telephone device 10 includes a control circuit 42 for controlling the entire device, a memory 44 storing a program for operating the wireless telephone device and data necessary for executing the program, and a mode setting for switching an operation mode described later. Switch 46,
Liquid crystal display (LCD) 48 and key switch 5
0 is provided.

The radiotelephone device 10 is operated by the mode setting switch 46 in one of a normal mode in which the same handover process is performed as in the prior art and a high-speed movement mode intended to be used during high-speed movement. It can be operated in mode.

In either mode, the wireless telephone 10 operates in the same manner as the conventional wireless telephone except for the handover process. That is, when a signal (radio wave) from a certain radio base station (CS: Cell Station) is received via the antenna 12, the signal received by the RF amplifier 14 is amplified, and then the output signal from the RF amplifier 14 is output. Is multiplied by the reception local oscillation signal from the frequency synthesizer 18 by the multiplier 16 and converted into an intermediate frequency signal, which is provided to the BPF 20.

The signal that has passed through the BPF 20 is supplied to a second multiplier 22, where the signal is multiplied by the output of a local oscillator 24 and frequency-converted. The signal of the predetermined frequency obtained in this way is supplied to the TDMA 28 as received data, and the audio data among them is
0 to the speaker SP. Also, TDM
The data (reception control data) corresponding to the control signal extracted in A28 is supplied to the control circuit 42.

On the other hand, the voice given through the microphone is encoded through the voice codec 30 and the TDMA 28, and then converted into an intermediate frequency signal by the modulator 32. The output of modulator 32 is then applied to a third multiplier 34
Is multiplied by the local oscillation signal from the frequency synthesizer 18 and converted into a signal of a predetermined frequency. The frequency-converted signal is provided to the antenna 12 via the BPF 36, the power amplifier 40, and the switch 13, and transmitted from the antenna 12. In this way, the wireless telephone device 30 can receive a signal from the wireless base station or transmit a signal to the wireless base station.

In the radio telephone apparatus operating as described above, when the talker moves and approaches the periphery (edge of the zone) of the zone covered by the radio base station currently in communication, the TDMA 28 transmits a bit. The error rate is detected to be greater than a predetermined threshold, or
It is detected that the electric field reception level is lower than the predetermined level, and information relating to this is supplied to the control circuit 42. The control circuit 42 performs a handover process according to the operation mode set by the mode setting switch 46. For example, as described in “Easy Personal Handy Phone” (edited by Keisuke Ogawa and Tadao Kobayashi: Telecommunications Association, Ohmsha), the handover process includes (1) a recall type handover request, and (2) a recurring handover request. The determined procedures of call-type handover acceptance, (3) RT function request, (4) secret key setting, (5) MM function request, and (6) response notification are executed.

The changeover switch 13 is for selecting an operation mode. The PHS operates in the normal mode when the normal mode is selected by the switch 13 and operates in the high-speed movement mode when the high-speed movement mode is selected. I do.

FIG. 2 is a flowchart showing the processing timings of the handover processing and the return processing when the wireless telephone device is operating in the normal mode, and a diagram showing an example of these processing timings. is there. In the normal mode, processing similar to that of the conventional wireless telephone device is executed. That is, the process is started in response to the deterioration of the voice quality or the reduction of the electric field level (step 20).
1) Then, the control device 42 receives the control data of the radio base station so as to search for a radio base station other than the radio base station currently communicating, and gives the control data to the TDMA 28 for handover. (Step 202). Thus, the wireless telephone device operates to search for another wireless base station. After a predetermined time (310 ms in the present embodiment) has elapsed after the processing of step 202, it is determined whether another wireless base station has been found (step 203).

If it is determined in step 203 that the answer is yes, the above-mentioned handover process is executed to change the connected radio base station (step 204). On the other hand, in step 203,
If it is determined that the wireless base station is out of range of the wireless base station, the control device 42 operates to emit an alarm sound, and disconnects from the original wireless base station. Return is performed (step 205). In the switching back process, when the caller moves into the area of the wireless base station again and the voice quality and the electric field level return to the original state, the caller
If the voice quality and the electric field level are not improved after a predetermined time (10 seconds in the present embodiment), the call is released. To forcibly end the call.

Next, a description will be given of a handover process and the like in the high-speed movement mode. FIG. 3 is a flowchart showing a handover process and the like when the wireless telephone device is operating under the high-speed movement mode, and
It is a figure showing an example of processing timing. Even in the high-speed movement mode, the processing is started in response to the deterioration of the voice quality or the decrease of the electric field level (step 301), and then the control device 42 transmits the handover to the base station that is currently communicating. To search for wireless base stations other than
The control data of the radio base station is received, and the
(Step 302). Thus, the wireless telephone device operates to search for another wireless base station. In the normal mode, it is determined whether or not a wireless base station has been found after a predetermined time (310 ms) has elapsed. However, in the high-speed movement mode, a second time longer than the predetermined time is determined. A predetermined time (in this embodiment, 10
After elapse of (seconds), it is determined whether a wireless base station has been found (step 303). That is, step 30
In 2, it is determined whether CS is always present during 10 seconds. Therefore, the handover process can be performed within 10 seconds. In the present embodiment, the second predetermined time corresponds to the time of the return processing in the normal mode.

If it is determined as YES at step 203, the above-described handover process is executed to change the connected radio base station (step 304). On the other hand, in step 203,
If it is determined that the call is released, the call is released and the call is terminated (step 305). During high-speed movement, there is a possibility that not only the wireless base station adjacent to the communicating (that is, connected) wireless base station but also a wireless base station farther away can be searched. For example, when talking by PHS while moving in a car, it is difficult to switch back in the first place. Also, since the car can move 150m in 10 seconds,
The search is not limited to the adjacent wireless base station, but may be skipped to search for an adjacent wireless base station. This means that the range (number) of searchable wireless base stations increases. In such a case, increasing the search time rather than increasing the time for switching back is more effective for maintaining communication. On the other hand, in the case of walking, it moves only about 15 m in 10 seconds, and such a case cannot be considered. As described above, in the present embodiment, by increasing the search time of the wireless base station under the high-speed movement mode, it is possible to find any wireless base station located adjacent to the movement route. Is higher. This makes it possible to increase the possibility of handover even during high-speed movement.

Embodiment 2 of the Invention Next, the second embodiment of the present invention
The wireless telephone device according to the embodiment will be further described. In this embodiment, the radiotelephone operates under a single mode of operation. Therefore, in this embodiment, the mode changeover switch 46 shown in FIG. 1 is omitted.

FIG. 4 is a flowchart showing the processing timings of the handover processing and the switching back processing of the radio telephone apparatus according to this embodiment, and a diagram showing an example of these processing timings. Also in this embodiment, the processing is started in response to the deterioration of the voice quality or the decrease of the electric field level (step 401). Transmission control data is generated so as to search for a wireless base station other than the station, and the transmission control data is provided to the TDMA 28 (step 402). Thus, the wireless telephone device operates to search for another wireless base station. After the process of step 402, a predetermined time (in the present embodiment, 500 m
After s) has elapsed, it is determined whether another wireless base station has been found (step 403).

If the determination is yes in step 403, the above-described handover process is executed to change the connected radio base station (step 404). On the other hand, in step 403,
When it is determined, the control device 42 operates to emit an alarm sound, notifies the caller that he / she will go out of the area of the wireless base station,
That is, the original wireless base station is searched (step 40).
5). After a predetermined time (500 ms in the present embodiment) has elapsed after the processing of step 405, it is determined whether or not the original wireless base station has been found (step 4).
06).

If it is determined as YES in step 406, the communication with the original wireless base station is continued (step 407). On the other hand, if it is determined as No (No) in step 406, it is determined whether or not a predetermined time for switching back (10 seconds in the present embodiment) has elapsed. (Step 408).

If the predetermined time has not yet elapsed, the flow returns to step 402, and the processing returns to step 4 again.
The process from 02 to step 406 is repeated, and when the time has elapsed, the call is released and the call is forcibly terminated (step 409).

According to this embodiment, in response to the deterioration of the sound quality, the search for the wireless base station for the handover and the search for the wireless base station to be switched back are performed at predetermined time intervals.
Since the operations are performed alternately, it is possible to increase the possibility that communication with any one of the wireless base stations will be established. This makes it possible to increase the possibility of handover not only during low-speed movement such as walking, but also during high-speed movement.

Embodiment 3 of the Invention Next, the third aspect of the present invention
The wireless telephone device according to the embodiment will be further described. Also in this embodiment, the radiotelephone operates under a single operating mode. Therefore, in this embodiment, the mode changeover switch 46 shown in FIG. 1 is omitted. In the wireless telephone device according to the third embodiment, the mode switching of the wireless telephone device according to the first embodiment is realized by detecting a key input during the switching process. In this regard, the third embodiment can be said to be a combination of the two modes in the first embodiment.

FIG. 5 is a flowchart showing the processing timings of the handover processing and the switching back processing of the wireless telephone device according to this embodiment, and a diagram showing an example of these processing timings. Also in this embodiment, the processing is started in response to the deterioration of the voice quality or the decrease of the electric field level (step 501), and then the control device 42 transmits the handover to the radio base station which is currently communicating. The control data of the wireless base station is received so as to search for a wireless base station other than the station, and the control data is provided to the TDMA 28 (step 502). Thereby, the wireless telephone device
Operate to search for other wireless base stations. Step 4
After a predetermined time (500 ms in the present embodiment) elapses after the process of 02, it is determined whether or not another wireless base station has been found (step 503).

If the determination is yes in step 503, the above-mentioned handover process is executed to change the connected radio base station (step 504). On the other hand, in step 503,
If it is determined that the caller has a predetermined key (FIG. 1)
It is determined whether or not an input has been made (step 505). This is because when a caller is moving at high speed, for example, when an alarm sound is issued from a wireless telephone due to sound quality deterioration, a predetermined key is input to search for a wireless base station for handover. It corresponds to. At this time, a message may be displayed on the LCD display 48. For example, a beep sound is generated, and the display 48 displays "The radio wave has become weaker. Return to the place where the radio wave becomes stronger.
If you cannot return, press the "#" key. Is displayed. The user can judge the situation promptly and select one of them.

Therefore, at step 505, the answer is yes (Y
If es) is determined, a wireless base station for handover is searched (step 507). In this search for the wireless base station, after a key input is made, step 501 is executed.
After the execution of the processing, a predetermined time (in this embodiment, 10
Seconds) (see FIG. 5B). After the search is completed, it is determined whether or not a wireless base station has been found, as in the case of the high-speed movement mode in the first embodiment shown in FIG. Performs a handover process and, if not found, releases the call (see steps 303 to 305 in FIG. 3). As described above, in the third embodiment, when the caller performs a predetermined key input during a call, the operating state of the wireless telephone device can be quickly moved from the normal mode described in the first embodiment. The change can be made to substantially correspond to the change to the mode.

On the other hand, at step 505, no (N
If determined to be o), the control device 42 operates to emit an alarm sound, notifies the caller that he / she will go out of the area of the wireless base station, and switches the wireless base station of the return destination. That is, the original wireless base station is searched (step 5).
06). After a lapse of a predetermined time (500 ms in the present embodiment) after the processing of step 506, it is determined whether or not the original wireless base station has been found (step 508).

If it is determined as YES at step 508, the communication with the original wireless base station is continued (step 509). On the other hand, if it is determined No in step 508, it is determined whether or not a predetermined time for switching back (10 seconds in the present embodiment) has elapsed. (Step 510).

If the predetermined time has not elapsed, the flow returns to step 505 to determine whether or not the caller has pressed a predetermined key.
The processing of steps 06 to 510 is repeated, and when a predetermined time has elapsed, the call is released and the call is forcibly terminated (step 511).

According to the present embodiment, when the caller performs a predetermined key input during a call, the operating state of the wireless telephone device is changed to the normal state (the normal mode in the first embodiment). It is possible to change from (correspondence) to a state (corresponding to the high-speed movement mode in the first embodiment) in which the possibility of handover is further increased even during high-speed movement. Therefore, even during a call, it is possible to change the operation state of the wireless telephone device as desired and to increase the possibility of handover as desired.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the invention described in the appended claims, which are also included in the scope of the present invention. Needless to say, this is done.

For example, in the second and third embodiments, the mode changeover switch for switching the operation mode is not provided. However, the present invention is not limited to this. In this case, the wireless telephone device may operate as shown in FIG. 2, and in other modes, the wireless telephone device may operate as shown in FIG. 4 or FIG.

In the first embodiment,
In the normal mode, the wireless base station for handover is searched for only 310 ms, and in the high-speed movement mode, the wireless base station for handover is searched for only 10 seconds. The present invention is not limited thereto, and may be set as appropriate depending on the wireless telephone device. Second and third
In the embodiment described above, the same applies to the search time of the wireless base station for handover and the search time of the wireless base station for switchback.

Further, in this specification, means does not necessarily mean physical means, but also includes a case where the function of each means is realized by software.
Further, the function of one unit may be realized by two or more physical units, or the function of two or more units may be realized by one physical unit.

[0054]

As described above, according to the present invention, the operation mode setting switch for setting the operation mode of the radio communication device and the other when the vehicle approaches the boundary of the coverage area of the connected radio base station, Search means for searching for a wireless base station, handover means for changing the connection from the connected wireless base station to the searched other wireless base station, and another wireless base station searched by the search means If there is no switchover, the switchover means for switching back to the connected wireless base station, and if the operation mode setting switch is set to the high-speed movement mode, the search means performs handover at the first time. When it is not possible to search for another wireless base station that can be executed, the switchback means is not operated and the second
Control unit for controlling the search means and the return means so as to execute a search at the time of, for example, whether the caller is walking, moving at high speed, etc. , As desired by the caller,
The operation mode of the wireless communication device can be set, so that handover can be appropriately performed in any case.

Further, according to the present invention, when approaching the boundary of the coverage area of the connected radio base station, the search means for searching for another radio base station, and the search means for searching from the connected radio base station A handover unit for changing the connection to the another radio base station that has been set, and a disconnection unit for executing a return to the connected radio base station when the other radio base station is not searched for by the search unit. Return means, return by the return means, and a search for another wireless base station by the search means,
Since the control unit controls the search unit and the return unit so as to be executed alternately, the search for the wireless base station for handover and the search for the wireless base station to be switched back alternately. , It is possible to increase the possibility that communication with any of the wireless base stations will be established. This makes it possible to increase the possibility of performing handover in various usage situations, for example, not only during low-speed movement such as walking, but also during high-speed movement, without having to set the operation mode. Become.

Further, according to the present invention, when approaching the boundary of the coverage area of the connected radio base station, the search means for searching for another radio base station, and the search means for searching from the connected radio base station A handover unit for changing the connection to the another radio base station that has been set, and a disconnection unit for executing a return to the connected radio base station when the other radio base station is not searched for by the search unit. Return means, and when the predetermined operation is performed, the search means and the return means are controlled so that the search means searches for another wireless base station without operating the return means. Since the control unit is provided, the possibility of finding another wireless base station can be increased, and the possibility of handover can be improved. In particular, when the caller is moving at high speed and cannot return to the coverage area of the original wireless base station, the search for the wireless base station is continued without switching back according to the situation at that time. Thus, handover can be more reliably realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a wireless telephone device according to a first embodiment of the present invention.

FIG. 2 shows a wireless telephone device according to the first embodiment;
It is a figure which shows the processing timing of a handover process and a switchback process under normal mode.

FIG. 3 shows a wireless telephone device according to the first embodiment;
It is a figure which shows the processing timing of a handover process and a switchback process under a high-speed movement mode.

FIG. 4 is a diagram illustrating processing timings of a handover process and a switchback process of the wireless telephone device according to the second embodiment;

FIG. 5 is a diagram illustrating processing timings of handover processing and switchback processing of the wireless telephone device according to the third embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Wireless telephone apparatus 12 Antenna 14 RF amplifier 16, 22, 34 Multiplier 18 Frequency synthesizer 20, 36 Bandpass filter 24 Local oscillator 26 Demodulator 28 TDMA 30 Voice codec 42 Control circuit 44 Memory 46 Mode setting switch

Claims (9)

[Claims] 1. A wireless communication device for communicating with another communication device by transmitting / receiving a signal via a wireless base station, comprising: an operation mode setting switch for setting an operation mode of the wireless communication device; Searching means for searching for another wireless base station when approaching the boundary of the coverage area of the wireless base station; and a hand for changing the connection from the connected wireless base station to the searched other wireless base station Over means, when no other wireless base station is searched by the search means, a return means for performing a return to the connected wireless base station, and a high-speed movement mode by the operation mode setting switch. When set, when the search means cannot search for another wireless base station capable of performing handover at the first time, the switchback means is not operated, and the search is performed for the second time. Wireless communication device and a control unit for controlling the retrieval means and the switching return means so as to execute the search. 2. The wireless communication device according to claim 1, wherein the second time is continuous with the first time and is longer than the first time. 3. The wireless communication apparatus according to claim 1, wherein the control unit causes the reverting unit to execute reverting at a third time after the second time. 4. A wireless communication device that communicates with another communication device by transmitting / receiving a signal via a wireless base station, wherein when the wireless communication device approaches a boundary of a coverage area of a connected wireless base station, the wireless communication device Search means for searching for a wireless base station, handover means for changing the connection from the connected wireless base station to the searched other wireless base station, and searching for another wireless base station by the search means If not, a switchback unit that performs a switchback to the connected wireless base station, a switchback by the switchback unit, and a search for another wireless base station by the search unit are performed alternately. And a control unit for controlling the retrieving means and the reverting means. 5. A wireless communication device that communicates with another communication device by transmitting / receiving a signal via the wireless base station, wherein when the wireless communication device approaches a boundary of the coverage area of the connected wireless base station, the wireless communication device Search means for searching for a wireless base station, handover means for changing the connection from the connected wireless base station to the searched other wireless base station, and searching for another wireless base station by the search means If not performed, a switchback unit that performs a switchback to the connected wireless base station; and when a predetermined operation is performed, without operating the switchback unit, another search by the search unit. A wireless communication apparatus comprising: a control unit that controls the search unit and the return unit so as to execute a search for a wireless base station. 6. The control section notifies the execution of the switchback, and, when notifying the switch, presses a predetermined switch during the notification, and does not operate the switchback means. 6. The wireless communication apparatus according to claim 5, wherein a search for another wireless base station is performed by the search. 7. A handover processing method for a wireless communication device that communicates with another communication device by transmitting / receiving a signal via a wireless base station, comprising: setting an operation mode of the wireless communication device in advance. Searching for another radio base station when approaching the boundary of the coverage area of the connected radio base station; and searching for the other radio base station from the connected radio base station. A connection changing step of changing a connection to a wireless base station when no other wireless base station is searched in the searching step, and performing a return to the connected wireless base station. When the mode is set to the high-speed movement mode, when the search step fails to search for another radio base station capable of executing handover at the first time, the switchback step is performed. Ukoto without further handover processing method of the wireless communication device search is performed at a second time. 8. A handover processing method for a wireless communication device that communicates with another communication device by transmitting / receiving a signal via a wireless base station, the method comprising: A search step for searching for another wireless base station, a connection changing step for changing the connection from the connected wireless base station to the searched other wireless base station, and If a wireless base station is not found, the method includes a failback step of performing a failback to the connected wireless base station, wherein the failback step and the searching step are performed alternately. A handover processing method for a wireless communication device. 9. A handover processing method for a wireless communication device that communicates with another communication device by transmitting / receiving a signal via a wireless base station, the method comprising: A search step for searching for another wireless base station, a search step for changing the connection from the connected wireless base station to the searched other wireless base station; and A switch-back step of performing a switch-back to the connected wireless base station when a base station is not searched, and when a predetermined operation is performed, without performing the switch-back step, A handover processing method for a wireless communication device, characterized by performing a search step.