JP2000106692A - Portable telephone set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a portable telephone set, where the probability of successfully acquiring a speech channel is enhanced when redialing, even when the acquisition of the speech channel has failed at first when dialing at a location having heavy call traffic. SOLUTION: A total control section 101 of a portable telephone set 100, that makes communication via radio base stations detects a failure in speech channel acquisition in the case of dialing and discriminates whether or not the operator makes a redialing instruction. A list generating section 103 captures the control signal of a surrounding radio base station, when the redialing instruction is received and generates a list where reception electric field strength of the captured control signal and the radio base station related to this control signal are made to correspond to each other. A protocol control section 104 redials the radio base station with the maximum reception electric field strength in from among a generated list to try to acquire the speech channel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable telephone in a mobile communication system such as a personal handyphone system (PHS).

[0002]

2. Description of the Related Art When a call is made from a portable telephone to another telephone or an incoming call is received from another telephone, the portable telephone transmits a control signal to obtain a communication line with a radio base station. Exchanges. FIG. 8 shows an example of a communication sequence in a case where the conventional portable telephone 10 fails to acquire a communication channel at the time of making a call and makes a call again by the "redial function". In this example, in the paging area of the radio base station 20 in which the position of the portable telephone 10 is registered, in addition to the radio base station 20, the radio base stations 30, 4
0 is present. Further, the mobile phone 10 waits for a control channel signal intermittently transmitted from the wireless base station 20. This corresponds to the received signal strength (Received Sig) of the radio wave transmitted from the radio base station 20 among the three radio base stations.
nal Strength Indicator (RSSI) is the largest.

[0003] As shown in FIG.
Transmits a “link channel establishment request” to the radio base station 20 to acquire a communication channel. On the other hand, the radio base station 20 does not have a vacant channel for the call, and therefore, "link channel allocation rejection"
0 is sent. Thereafter, when the operator presses the “redial key”, the portable telephone 10 is connected to the wireless base station 2.
0, a “link channel establishment request” is transmitted again,
Make an attempt to get a communication channel. However, the radio base station 20 transmits “link channel assignment rejection” again because there is no vacancy in the channel for the call.

FIG. 9 shows an example of a communication sequence in an incoming call response when the conventional portable telephone 10 fails to acquire a communication channel at the time of an incoming call response and receives a call again.
The portable telephone 10 knows that a call has been received by the paging signal of the radio base station 20 that is waiting for reception among the paging signals of the control channels transmitted from the respective radio base stations. Next, the portable telephone 10 transmits a “link channel establishment request” to the wireless base station 20 in order to respond to the incoming call. On the other hand, the wireless base station 20 transmits “link channel allocation rejection” to the mobile phone 10 because there is no available channel for a call. After the “link channel assignment rejection” is transmitted from the radio base station 20,
After several seconds, each wireless base station in the paging area again transmits a paging signal of the same caller to the portable telephone 10 again. As a result, the portable telephone 10 is
After receiving the paging signal transmitted again from, a "link channel establishment request" is transmitted to the wireless base station 20 again, and an attempt is made to acquire a communication channel.

As described above, in the conventional portable telephone,
Each time a re-call or a response to a re-arrived call is made, the exchange for acquiring a channel for the call is repeated.

[0006]

However, according to the above-mentioned conventional portable telephone, when a user places a call in a place having a large traffic volume such as a downtown area, the base station issues a "link channel allocation rejection". However, even if a call is tried again by redialing within a shorter period of time, there is a problem that a telephone call is not often made.

More specifically, in the portable telephone system, the number of lines (the number of channels for communication) managed by one radio base station is small, and the portable telephone system is installed in a place such as a downtown area where the traffic volume is large. Wireless base stations often have no available channels. In this case, as shown in FIG. 8, even if the portable telephone 10 makes a call, a "link channel allocation rejection" is received from the radio base station 20. In this situation, even if a user who wants to start a call due to urgency or the like makes a call by redialing, the user receives a “link channel assignment rejection” again unless the condition that there is no free channel in the radio base station 20 is resolved. become. Inevitably, the user repeats the redial until the condition that there is no empty channel is eliminated.

[0008] A similar problem also occurs when an incoming call is answered. That is, after transmitting the "link channel allocation rejection", the radio base station 20 again transmits an incoming call notification from the same caller as a paging signal (for example, in the case of a public base station, after four seconds). One retransmission, and the self-operating base station retransmits several times about every 4 seconds.) In this case, the portable telephone 10 is connected to the radio base station 20 that is waiting for reception.
If there is no available channel, as shown in FIG. 9, a "link channel allocation rejection"
, And will receive "link channel assignment rejection" even if it responds to the next second paging call.

In view of the above, the present invention has been made in view of the above-mentioned problems. Even if acquisition of a communication channel fails at the time of outgoing call or incoming call response in a place where there is a large amount of traffic, the present invention is applied to the case where the call is made again. It is another object of the present invention to provide a portable telephone having an increased probability of successfully acquiring a communication channel at the time of receiving a call again.

[0010]

In order to achieve the above object, a portable telephone according to the present invention is a portable telephone which communicates via a radio base station, and fails to acquire a line at the time of calling. Detecting means for detecting whether or not there is a re-call instruction of the operator within a predetermined time after the detection of the line acquisition failure, and a radio base station which has failed to obtain the line if there is a re-call instruction. List creation means for acquiring a control signal of a peripheral wireless base station excluding the above, and creating a list in which information indicating the received electric field strength of the captured control signal is associated with an identifier of the wireless base station transmitting the control signal. Storage means for storing the created list, and recalling means for referring to the list stored in the storage means and recalling a radio base station transmitting a control signal having the maximum reception electric field strength. .

In order to achieve the above object, a portable telephone according to the present invention is a portable telephone which performs communication via a radio base station, and detects a failure of line acquisition when answering an incoming call. Detecting means for determining whether or not there is a re-arrived call within a predetermined time from the detection of the line acquisition failure; and List creation means for acquiring a control signal of a base station, and creating a list in which information indicating the received electric field strength of the captured control signal is associated with an identifier of a wireless base station transmitting the control signal; And re-response means for responding to the radio base station transmitting the control signal having the maximum received electric field strength with reference to the list stored in the storage means.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a portable telephone according to the present invention will be described below with reference to the drawings.
FIG. 1 shows a portable telephone 100 and wireless base stations 20 and 3.
1 is a schematic diagram of a portable telephone system including 0 and 40. FIG. As shown in FIG. 1, the portable telephone 100 and each wireless base station belong to the same general call area. Also,
The mobile phone 100 belongs to a wireless zone of any wireless base station, and performs standby reception of a control signal transmitted from any one wireless base station.

FIG. 2 is a functional configuration diagram of the portable telephone 100. The mobile phone 100 includes an overall control unit 101, a reception unit 102, a list creation unit 103, a protocol control unit 1
04, timer section 105, input operation section 106, transmission section 10
7 is comprised. The overall control unit 101 is realized by, for example, a microcomputer or the like, and controls the entire mobile phone 100. Hereinafter, the functions of the overall control unit 101 at the time of calling and answering a call will be described.

At the time of calling, the overall control unit 101 detects whether or not a communication channel has been allocated based on the content of the control signal received via the receiving unit 102.
The overall control unit 101, when receiving a dial input from the operator, identifies whether the call is a call or a recall, and in the case of a call, activates a “recall monitor timer” for the timer unit 105. To instruct. Further, when the assignment of the communication channel to the outgoing call has failed, and subsequently the instruction of the re-calling is detected by the operator pressing the “redial key” or the like, the overall control unit 101 sets the “re-call monitoring timer” before the expiration. If so, the receiving unit 102 is instructed to measure the received electric field strength of the control signals transmitted from the surrounding wireless base stations except the wireless base station for which the channel acquisition has failed. Further, overall control section 101 instructs list creation section 103 to create a “communicable base station list” based on the measured received electric field strength. Further, the overall control unit 101
Specifies the radio base station having the maximum received electric field strength based on the “communicable base station list”, and notifies the protocol control unit 104 of the CS-ID of the radio base station.

Here, the "communicable base station list"
4 is a list describing information on surrounding wireless base stations created by the mobile phone 100. In this communicable base station list, the received field strength of the control signal transmitted by the wireless base station is associated with the CS-ID of the wireless base station. “CS-ID” is information for identifying a wireless base station included in the control signal.

On the other hand, in response to the incoming call, the overall control unit 1
01 responds to the incoming call and detects whether or not a communication channel has been allocated based on the content of the control signal received via the receiving unit 102. When detecting a failure in allocating a communication channel to an incoming call response, the overall control unit 101 activates a “recall monitoring timer” to transmit from a surrounding wireless base station except for a wireless base station that failed to acquire a line. Receiving section 1 so as to measure the received electric field strength of the control signal to be received.
02 is indicated. Further, overall control section 101 instructs list creation section 103 to create a “communicable base station list” based on the measured received electric field strength. Further, the overall control unit 101 specifies the radio base station having the maximum reception electric field strength based on the created “communicable base station list”, and notifies the protocol control unit 104 of the CS-ID of this radio base station. I do. The overall control unit 101
Instructs the timer unit 105 to activate a "re-incoming call monitoring timer" every time a re-incoming call is detected.

Receiving section 102 waits for a control signal on a control channel intermittently transmitted from the radio base station, and intermittently receives the control signal. Further, receiving section 102 measures the received electric field strength of the control signal transmitted from the surrounding radio base station in accordance with the instruction of overall control section 101 and, based on the content of the received control signal, determines the CS-level of the surrounding radio base station. Identify the ID. Further, receiving section 102 receives a control signal transmitted from the radio base station at the time of re-calling and at the time of re-calling response.

The list creation unit 103 includes an overall control unit 101
Of the received electric field strength and the CS of each radio base station based on the received electric field strength measured by the receiving section 102.
-Create a "communicable base station list" associated with the ID. The protocol control unit 104 controls the mobile phone 1
The communication sequence and the data format at the time of calling and re-calling at 00 and at the time of incoming call response and re-incoming call response are controlled. The protocol control unit 104 receives the CS-
It controls a communication sequence for receiving assignment of a communication channel from a wireless base station having an ID.

The timer unit 105 has a "recall monitoring timer".
And a “recall monitoring timer”. Here, "re-call" means that the telephone 100 calls the same party within a certain period of time. Also, "Recall"
This means that the telephone 100 receives a paging call based on a call from the same party within a certain period of time. The overall control unit 101 constantly monitors the values of the “re-call monitoring timer” and “re-call monitoring timer”.

The “recall monitoring timer” is provided by the overall control unit 10.
In response to the instruction 1, when the communication channel allocation failure is detected at the time of calling and re-calling, the time can be regarded as “re-calling” after the start of calling and after the detection of communication channel assignment failure at the re-calling (for example, 60). Seconds). Further, the “re-incoming call monitoring timer” is provided in the overall control unit 10.
In response to the instruction of No. 1, it is activated upon detection of a communication channel allocation failure in the incoming call response and upon detection of a re-arrived call. Is measured (for example, 4 seconds).

For example, when the value of the "recall monitoring timer" is set to "60"
When “second” is set, the overall control unit 101 regards “recurrent call” before the value of the “recurrent call monitoring timer” becomes “0” as “recurrent call” targeted in the present embodiment. Also, for example, when the value of the “re-arrival monitoring timer” is set to “4 seconds”,
The overall control unit 101 regards a “re-arrived call” before the value of the “re-arrived call monitoring timer” becomes “0” as a “re-arrived call” from the same partner, and is a target of the present embodiment. .

The input operation unit 106 has ten keys (numerical keys), various function keys, and the like, and receives an input for setting a "redial key" or a timer from an operator. Further, transmitting section 107 transmits a control signal for receiving assignment of a communication channel to the wireless base station via the antenna. Next, the operations of the portable telephone 100 at the time of calling and answering a call will be described in detail with reference to FIGS. (Operation at the time of calling) FIG. 3 is a diagram showing a communication sequence until the portable telephone 100 receives a communication channel assignment at the time of calling. 4 (a) to 4 (c)
FIG. 4 is a diagram showing an example of the contents of the “communicable base station list” when the portable telephone 100 makes a call again.

First, the portable telephone 100 transmits a “link channel establishment request” signal to the radio base station 20. On the other hand, the radio base station 20 transmits a “link channel allocation rejection” signal to the mobile phone 100 because there is no available channel. Next, after detecting the pressing of the “redial key” or the like by the operator, the mobile phone 100 receives a control signal transmitted from a surrounding wireless base station except for the wireless base station 20 for which the line acquisition has failed. , And measure the respective received electric field strengths. Further, the portable telephone 100 sets the “communicable base station list” in which the CS-IDs indicating the respective base stations are associated with each other based on the measured received electric field strength.
Create FIG. 4A shows an example of the contents of the “communicable base station list” created in this case.

Thereafter, portable telephone 100 transmits a "link channel establishment request" signal to radio base station 30 corresponding to the maximum received electric field strength from the "communicable base station list". However, since there is no vacant channel in the wireless base station 30, the mobile phone 100 receives a “link channel assignment rejection” signal from the wireless base station 30.

As a result, the portable telephone 100 deletes the data of the wireless base station 30 to which the communication channel could not be allocated from the “communicable base station list”. FIG.
(b) shows the contents of the “communicable base station list” when the data of the base station 30 has been deleted. Further, the mobile phone 100 transmits a “link channel establishment request” signal to the wireless base station 40 corresponding to the maximum received electric field strength in the “communicable base station list” after the data is deleted. . On the other hand, the radio base station 40 transmits a “link channel allocation” signal to the mobile phone 100 because there is a channel to be allocated.

With the above communication sequence, the portable telephone 100 can make a call connection at the time of calling. Note that when the wireless base station 40 receives no “link channel allocation rejection” signal from the wireless base station 40 because there is no available channel, the portable telephone 100 again measures the received electric field strength including the wireless base station 20. And a "communicable base station list" is created. FIG. 4 (c) shows the contents of the "communicable base station list" created based on the measurement of the received electric field strength again.

FIG. 5 is a flowchart showing a flow of processing until the portable telephone 100 receives a communication channel assignment at the time of calling. In this processing, a communication channel is not allocated in the radio base station 20 for a call from the portable telephone 100, and the radio base station 20
After receiving a "link channel assignment rejection" signal from
It is activated when a re-call is instructed by the operator using a “redial key” or the like. Although not shown in FIG. 5, the "recall monitoring timer" is activated when a call is detected before this process is activated.

First, the overall control unit 101 determines whether or not the "recall monitoring timer" has expired (step S50).
1) If it has expired, the exchange for receiving the communication channel assignment is continued with the wireless base station that could not receive the communication channel assignment at the time of calling (step S508). On the other hand, when the “recall monitoring timer” has not expired, overall control section 101 issues an instruction to receiving section 102. Thereby, the receiving unit 102
Receives the control signal transmitted from the surrounding wireless base station and measures the received electric field strength (step S50).
2). Next, the overall control unit 101 determines whether there is a communicable wireless base station other than the wireless base station to which the communication channel could not be allocated, based on the measurement result of the received electric field strength (step S503). . If there is another communicable wireless base station, the overall control unit 101
Instruct 3 As a result, the list creation unit 103
Create a “communicable base station list” (step S50)
4).

Next, the overall control unit 101 determines whether or not the "recall monitoring timer" has expired (step S505).
If the communication time has expired, the wireless base station, which could not receive the communication channel assignment at the time of calling, continues the exchange for receiving the communication channel assignment (step S508). On the other hand, when the “recall monitoring timer” has not expired, the overall control unit 101 determines whether or not there is data in the “communicable base station list” (step S506). The electric field strength is measured and the “communicable base station list” is created again (step S502). If there is data in the “communicable base station list”, the overall control unit 101 specifies the wireless base station having the maximum received electric field strength from the “communicable base station list” and performs protocol control on its CS-ID. Notify section 104. As a result, the protocol control unit 104 transmits a “link channel establishment request” signal to the wireless base station corresponding to the notified CS-ID via the transmission unit 107 (step S507).

When there is no other communicable base station (step S503), the overall control unit 101 sends a "link channel establishment" message to the radio base station that could not receive a communication channel at the time of calling. The protocol control unit 104 is instructed to continue transmitting the “request” (step S508). Thereafter, the overall control unit 101
"Link channel assignment" received via receiving section 102
A signal or a "link channel assignment rejection" signal is confirmed (step S509). When the reception of the “link channel assignment” signal is confirmed, the overall control unit 101 shifts to a wireless path setting process and a call process (step S515).
When the overall control unit 101 confirms the reception of “link channel allocation rejection”, it instructs the timer unit 105 to start the “recall monitoring timer” (step S51).
0). Further, before the expiration of the “recall monitoring timer”, the operator detects an input indicating that recall is to be performed (or a signal as part of the redial function), and there is data in the “communicable base station list”. In this case (steps S511 to S513), the overall control unit 101 instructs the list creation unit 103 to delete data of wireless base stations for which communication channels could not be allocated from the “communicable base station list”. (Step S514).

The above processing is repeated until the "recall monitoring timer" expires (steps S505 to S514). As described above, according to the mobile phone of the present embodiment, when a call is made, a re-call is performed to another wireless base station having the maximum received electric field strength of the wireless base station that has failed to acquire the communication channel. Even if the acquisition of a communication channel fails when a call is made in a place where there are many calls, the probability of successfully acquiring the communication channel when calling again can be increased.

In the above-described embodiment, the fixed time for which the recalling can be regarded as a recalling call of the "recalling monitoring timer" is set to 60 seconds. It may be a very long time (for example, several months). (Operation at the time of incoming call response) FIG.
FIG. 8 is a diagram showing a communication sequence until receiving a communication channel assignment at the time of an incoming call response.

First, the portable telephone 100 receives a paging call from the radio base stations 20, 30, and 40, and
0, a "link channel establishment request" signal is transmitted. However, the wireless base station 20 transmits a “link channel assignment rejection” signal to the mobile phone 100 because there is no available channel. Thereby, the portable telephone 100 measures the received electric field strength (S
601), a “communicable base station list” in which the received electric field strength is associated with the CS-ID of the wireless base station is created (S6).
02). In this case, the "communicable base station list"
Are the same as those in FIG.

Thereafter, when the portable telephone 100 receives a simultaneous call from the wireless base stations 20, 30, and 40 again,
A “link channel establishment request” signal is transmitted to the wireless base station 30 corresponding to the maximum reception electric field strength from the “communicable base station list”. However, the radio base station 30
Transmits a “link channel allocation rejection” signal to the mobile phone 100 because there is no available channel. Thereby, the mobile phone 100 deletes the data of the wireless base station 30 from the “communicable base station list” (S6).
03). The contents of the “communicable base station list” in this case are the same as those in FIG.

Further, when the portable telephone 100 receives a simultaneous call from the radio base stations 20, 30, and 40 again,
A “link channel establishment request” signal is transmitted to the wireless base station 40 corresponding to the maximum received electric field strength from the “communicable base station list”. On the other hand, the radio base station 4
Since “0” has a channel to be assigned, a “link channel assignment” signal is transmitted to the mobile phone 100.

With the above communication sequence, the portable telephone set 100 can receive a communication channel at the time of receiving a call. FIG. 7 shows a portable telephone 10.
0 is a flowchart showing the flow of processing until a communication channel is allocated at the time of an incoming call response. This processing is performed after the mobile phone 100 receives the “link channel allocation rejection” signal from the wireless base station 20 without the communication channel being allocated from the wireless base station 20 in response to the incoming response of the mobile phone 100. Is activated.

First, the overall control unit 101 instructs the timer unit 105 to start the "re-incoming call monitoring timer" (step S701). Also, the overall control unit 101
Sends an instruction to the receiving unit 102 to measure the received electric field strength as in the case of the calling. Thereby, the receiving unit 102
The received electric field strength is measured by the control signal transmitted from the surrounding wireless base station (step S702).

Next, the overall control unit 101 determines whether there is a communicable base station other than the radio base station to which the communication channel could not be allocated (step S70).
3) If there is another communicable radio base station, the list creation unit 103 is instructed. Thereby, the list creation unit 1
03 creates a “communicable base station list” (step S704). If there is no other wireless base station that can communicate,
The overall control unit 101 instructs the protocol control unit 104 to continue transmitting the “link channel establishment request” to the wireless base station to which the communication channel could not be allocated, after waiting for the next general call. (Step S71
0, step S711).

Further, if there is a re-calling before the "re-calling monitoring timer" expires and there is data in the "communicable base station list" (steps S705 to S708), the general control unit 101 sets "communication". A “link channel establishment request” signal is transmitted from the “possible base station list” to the wireless base station having the maximum reception electric field strength via the transmission unit 107 (step S709). Note that the overall control unit 101
Each time a re-incoming call is detected, an instruction is issued to the timer unit 105 to activate the “re-incoming call monitoring timer”.

Thereafter, the overall control unit 101 controls the receiving unit 10
Then, the “link channel allocation” signal or the “link channel allocation rejection” signal received via the communication device 2 is confirmed (step S712). When confirming the reception of the “link channel assignment” signal, the overall control unit 101 shifts to a wireless path setting process and a call process (step S715). On the other hand, when the overall control unit 101 confirms the reception of the “link channel allocation rejection” signal, from the “communicable base station list”,
The data of the base station to which the communication channel could not be allocated is deleted (step S714), and the next call arrival is monitored. Note that the process for acquiring the communication channel is repeated until the “re-incoming call monitoring timer” expires (steps S705 to S714).

As described above, according to the portable telephone of the present embodiment, the call response is returned to another radio base station having the maximum reception electric field strength which failed to acquire the communication channel at the time of the call response. Therefore, even if the acquisition of the communication channel fails at the time of the incoming call response in a place where the traffic volume is large, the probability of successfully acquiring the communication channel at the time of the incoming call response again can be increased.

[0042]

As is apparent from the above description, the portable telephone according to the present invention is a portable telephone which communicates via a radio base station, and detects a failure in acquiring a line at the time of calling. Detecting means, determining means for determining whether or not there is an operator's recall instruction within a predetermined time after the detection of the line acquisition failure; List creation means for acquiring a control signal of the wireless base station, and creating a list in which information indicating the received electric field strength of the captured control signal is associated with an identifier of the wireless base station transmitting the control signal. Storage means for storing a list stored in the storage means, and recall means for calling a radio base station transmitting a control signal having a maximum received electric field strength with reference to the list stored in the storage means.

Thus, at the time of re-calling, a list is created by searching for a wireless base station having a communicable reception electric field strength other than the wireless base station that failed to acquire a line at the time of calling, and a list is created. Is re-established to the wireless base station having the received electric field strength of, so that the probability of successful channel acquisition can be increased. Further, the list creation means captures a control signal of a peripheral wireless base station excluding a wireless base station for which a line acquisition has failed when there is an operator's recall instruction and the list does not exist in the storage means. A creating unit for creating a list in which the information indicating the received electric field strength of the captured control signal and the identifier of the radio base station relating to the control signal are created; and In the case where the list exists, a change unit that deletes information indicating the reception field strength and the identifier related to the radio base station for which the line acquisition has failed from the list may be provided. Thereby, if there is no list indicating the wireless base station having a communicable reception electric field strength, this list is newly created, and if the wireless base station that tried to acquire the line at the time of recalling failed to acquire the line, Since the information related to the wireless base station is deleted from this list, it is possible to always ensure the information for successfully acquiring the line in the list.

Further, when the change unit deletes all the information indicating the received field strength and the identifier from the list, the creation unit includes the radio base station that failed to acquire the line at the time of the call. Alternatively, a control signal of a nearby wireless base station may be captured to create a list in which information indicating the received electric field strength of the captured control signal is associated with an identifier of the wireless base station transmitting the control signal. As a result, if all the radio base stations that attempted to acquire the line at the time of recalling failed to acquire the line, and if all the information related to the radio base station was deleted from the above list, the line acquisition would fail at the first call. Since the above list is created again including the wireless base station that has been set, it is possible to always specify a wireless base station suitable for successfully acquiring a line at the time of re-calling.

A portable telephone according to the present invention is a portable telephone which communicates via a radio base station, comprising: detecting means for detecting a failure in line acquisition when responding to an incoming call; Determining means for determining whether or not there is a re-incoming call within a predetermined time from the detection of the control signal. List creating means for creating a list in which information indicating the received electric field strength of the captured control signal and the identifier of the wireless base station transmitting the control signal are stored, and storage means for storing the created list, Re-response means for referring to the list stored in the storage means and responding to the wireless base station transmitting the control signal having the maximum received electric field strength.

In this way, at the time of re-answering a call, a list is created by searching for a radio base station having a communicable reception electric field strength other than the radio base station that failed to acquire a line at the time of the call response. Of the above, the incoming call response is again made to the wireless base station having the maximum received electric field strength, so that the probability of successfully acquiring the line can be increased. Further, the list creating means captures a control signal of a peripheral wireless base station excluding the wireless base station for which the line acquisition has failed when there is a re-incoming call and the list does not exist in the storage means. A creating unit that creates a list in which information indicating the received electric field strength of the control signal that has been transmitted and the identifier of the wireless base station that transmits the control signal, a call is received again, and the list exists in the storage unit. In such a case, a configuration may be provided in which a change unit that deletes information indicating the received field strength and the identifier relating to the wireless base station for which the line acquisition has failed from the list is deleted. By this, if there is no list indicating the wireless base stations having the reception electric field strength that can be communicated, this list is newly created, and the wireless base station which tried to acquire the line at the time of answering the call again fails to acquire the line. Deletes the information related to the wireless base station from this list, so that the information for successfully acquiring the line can always be secured in the list.

Further, when the change unit deletes all the information indicating the reception field strength and the identifier from the list, the creation unit also includes the radio base station which failed to acquire the line at the time of the call reception. Alternatively, a control signal of a nearby wireless base station may be captured to create a list in which information indicating the received electric field strength of the captured control signal is associated with an identifier of the wireless base station transmitting the control signal. As a result, since all the radio base stations that tried to acquire the line at the time of the call response again failed to acquire the line, if all the information related to the radio base station was deleted from the list, the line acquisition was performed at the time of the first call response. Since the above list is created again including the radio base station that failed, the radio base station suitable for always successfully acquiring the line can be specified at the time of the incoming call response again.

[Brief description of the drawings]

FIG. 1 shows a mobile phone 100 and wireless base stations 20, 3.
1 is a schematic diagram of a portable telephone system including 0 and 40. FIG.

FIG. 2 is a functional configuration diagram of the mobile phone 100.

FIG. 3 is a diagram showing a communication sequence until a communication channel is allocated when a call is made from the portable telephone set 100.

FIG. 4A is a diagram showing an example of the contents of an initial “communicable base station list” created at the time of re-calling or re-arrival of the portable telephone 100; (b) is a diagram showing an example of the contents of the “communicable base station list” corrected at the time of re-calling or re-calling response of the portable telephone 100. (c) is a diagram showing an example of the contents of the “communicable base station list” created again when the portable telephone 100 recalls or responds to the incoming call again.

FIG. 5 is a flowchart showing a flow of processing until a communication channel is assigned when the portable telephone 100 makes a call.

FIG. 6 is a diagram showing a communication sequence up to receiving a communication channel assignment when the portable telephone 100 receives a call;

FIG. 7 is a flowchart showing a flow of processing until a communication channel is assigned when the portable telephone 100 receives a call;

FIG. 8 is an example of a communication sequence in a case where a conventional portable telephone makes a call again after failing to acquire a communication channel at the time of calling.

FIG. 9 is an example of a communication sequence in an incoming call response when a conventional portable telephone fails to acquire a communication channel at the time of an incoming call response and receives an incoming call again.

[Explanation of symbols]

 10, 100 Mobile phone 20, 30, 40 Radio base station 101 Overall control unit 102 Receiving unit 103 List creation unit 104 Protocol control unit 105 Timer unit 106 Input operation unit 107 Transmission unit

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Atsuo Fujita 3-10-18 Kagamiyama, Higashihiroshima City Matsushita Electric Information Systems Hiroshima Laboratory F-term (reference) 5K067 AA25 BB04 DD19 DD23 EE02 GG07 HH23 JJ54 JJ69 JJ72 KK15

Claims (6)

[Claims] 1. A portable telephone which performs communication via a radio base station, comprising: a detecting means for detecting a failure of line acquisition at the time of calling, and a recurrence of an operator within a predetermined time after the detection of the line acquisition failure. Determining means for determining whether there is a call instruction; and, if there is a re-call instruction, capturing control signals of peripheral wireless base stations excluding the wireless base station for which the line acquisition has failed, and receiving electric field of the captured control signal. List creation means for creating a list in which information indicating the strength is associated with the identifier of the wireless base station transmitting the control signal; storage means for storing the created list; and a list stored in the storage means Recalling means for calling a radio base station transmitting a control signal having a maximum received electric field strength. 2. The method according to claim 1, wherein said list creation means controls the surrounding radio base stations excluding the radio base station for which the line acquisition has failed when the operator has issued a recall instruction and said list does not exist in said storage means. There is a creating unit that captures the signal and creates a list in which information indicating the received electric field strength of the captured control signal and the identifier of the wireless base station that transmits the control signal are associated with each other. And a change unit that deletes, from the list, information indicating a received electric field strength and an identifier related to a radio base station that failed to obtain a line after calling by the re-calling unit from the list when the list is present in the storage unit. The portable telephone according to claim 1, wherein: 3. The radio base station according to claim 2, wherein, when the change unit deletes all of the information indicating the received field strength and the identifier from the list, the radio base station fails to acquire the line at the time of the call. And capturing a control signal of a peripheral wireless base station including, and creating a list in which information indicating the received electric field strength of the captured control signal is associated with an identifier of the wireless base station transmitting the control signal. The mobile phone according to claim 2, wherein 4. A portable telephone which communicates via a radio base station, comprising: detecting means for detecting a failure of line acquisition when responding to an incoming call; Determining means for determining whether there is a call; and, when there is a re-arrival call, capturing control signals of peripheral wireless base stations excluding the wireless base station for which the line acquisition has failed, and receiving electric field strength of the captured control signal. List creating means for creating a list in which information indicating a wireless base station transmitting the control signal is associated with the information indicating the list, storage means for storing the created list, and a list stored in the storage means. And a re-response means for responding to a wireless base station transmitting a control signal having a maximum received electric field strength. 5. The list creation means captures a control signal of a peripheral wireless base station excluding a wireless base station for which line acquisition has failed, when a call is received again and the list does not exist in the storage means. A creating unit that creates a list in which information indicating the received electric field strength of the captured control signal is associated with the identifier of the wireless base station that transmits the control signal; and 5. The information processing apparatus according to claim 4, further comprising: a change unit that deletes, from the list, information indicating a received electric field strength and an identifier relating to the radio base station that failed to acquire the line after the response by the re-response unit. A portable telephone as described. 6. The radio base station which has failed to acquire a line at the time of the incoming call when all of the information indicating the received field strength and the identifier are deleted from the list by the change unit. And capturing a control signal of a peripheral wireless base station including, and creating a list in which information indicating the received electric field strength of the captured control signal is associated with an identifier of the wireless base station transmitting the control signal. The mobile phone according to claim 5, wherein