JP2007150478A - Radio communication system, radio communication method, communication terminal in radio communication system and program thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio communication system for reducing system load of a base station due to requests of position registration which are issued in reselection processing because many communication terminals execute the reselection processing at a time after redirection processing. <P>SOLUTION: A communication terminal 2 determines whether an incoming call has arrived. If predetermined conditions are satisfied and it is determined that an incoming call has not arrived based on the above determination, the communication terminal 2 executes capturing processing for a base station to be selected based on priority. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a radio communication system and a radio communication method in which a base station and a communication terminal perform radio communication, a terminal in the radio communication system, and a program thereof.

2. Description of the Related Art Conventionally, in a wireless communication system in which a base station and a communication terminal perform wireless communication using a communication method such as a CDMA digital mobile communication method, the base station is triggered by the occurrence of a communication failure in the base station or congestion of transmitted / received data. A station performs processing for prompting a communication terminal in a standby state for its own base station to switch the standby destination to another base station. This process is called redirection, and when the base station transmits redirection information to the communication terminal, the communication terminal performs capture processing to switch the standby destination to another base station by receiving the redirection information. In addition, each communication terminal that has received the redirection information, after finishing the redirection process, selects a high-priority base station stored in its own terminal after a predetermined time has elapsed, and waits for that base station. Perform capture processing. This process of capturing a communication terminal is called reselection. After the reselection process, each communication terminal makes a location registration request to the base station using its own terminal ID or the like. As a related technique, Patent Document 1 discloses a technique in which a communication terminal captures a base station according to reception intensity.
JP 2000-69553 A

  By the way, when the above-mentioned reselection process and incoming call process occur simultaneously in the communication terminal, the communication terminal cancels the incoming call process and gives priority to the reselection process. The communication terminal does not perform the incoming call process until the reselection process and the location registration process are completed. Therefore, there has been a problem that the incoming rate at the communication terminal is lowered.

  Accordingly, an object of the present invention is to provide a radio communication system and a radio communication method, a communication terminal in the radio communication system, and a program thereof for the purpose of preventing a decrease in the incoming rate of the communication terminal.

  In order to achieve the above object, the present invention is a wireless communication system comprising a plurality of base stations and a communication terminal capable of wireless communication with any one of the plurality of base stations, The communication terminal stores acquisition priority storage means for storing the priority of a base station that performs acquisition, incoming call presence / absence determination means for determining presence / absence of an incoming call at the own terminal, and predetermined conditions when the own terminal is in a standby state. An acquisition instruction for instructing acquisition to the base station selected based on the priority stored in the acquisition priority storage means when it is determined that the incoming / outgoing presence determination means determines that the incoming call is not received And a capture processing means for performing a capture process on the selected base station based on the capture instruction.

  Further, the present invention provides the capture instruction after the termination of the incoming call processing when the capture instruction unit determines that the incoming call presence determination unit determines that the incoming call is being received when the predetermined condition is satisfied. It is characterized by performing.

  The present invention is also a wireless communication method in a wireless communication system comprising a plurality of base stations and a communication terminal capable of wireless communication with any one of the plurality of base stations, the communication terminal Stores the priority of the base station that performs acquisition, determines whether or not there is an incoming call at the communication terminal, and satisfies a predetermined condition when the communication terminal is in a standby state, and the communication terminal is not receiving an incoming call. When it is determined, the base station selected based on the priority is instructed to capture, and the communication terminal performs a capturing process on the selected base station based on the capture instruction. A wireless communication method.

  Further, the present invention is the communication terminal in a wireless communication system including a plurality of base stations and a communication terminal capable of wireless communication with any one of the plurality of base stations, and performs capture Capture priority storage means for storing the priority of the base station, incoming / outgoing presence / absence determining means for determining whether or not there is an incoming call at the own terminal, and whether or not the predetermined condition is satisfied when the own terminal is in a standby state When the means determines that the incoming call is not received, the acquisition instruction means for instructing acquisition to the base station selected based on the priority stored in the acquisition priority storage means, and the acquisition instruction And a capture processing means for performing capture processing on the selected base station based on the communication terminal.

  The present invention is also a program to be executed in a wireless communication system comprising a plurality of base stations and a communication terminal capable of wireless communication with any one of the plurality of base stations, the communication terminal An incoming / outgoing presence determination process for determining the presence / absence of an incoming call in the network, and a base that performs acquisition when a predetermined condition is satisfied when the communication terminal is in a standby state and the incoming / outgoing presence determination process determines that no incoming call is received. A capture instruction process for selecting a base station based on the priority stored in the capture priority storage means for storing the priority of the station and instructing the selected base station to capture, and the capture instruction And the acquisition process of the communication terminal to the selected base station.

  According to the present invention, a base station that determines the presence or absence of an incoming call to a communication terminal, that satisfies a predetermined condition when the communication terminal is in a standby state, and that is selected based on the priority when the communication terminal is not receiving an incoming call Since the acquisition process is executed, if the incoming call is being received, the process for giving priority to the incoming process is performed without performing the acquisition process. Therefore, the incoming rate can be improved.

Hereinafter, a wireless communication system according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing the overall configuration of the wireless communication system according to the embodiment.
In this figure, both the radio base station A and the radio base station B perform radio communication with the communication terminal 2 using a CDMA digital mobile communication system. The radio base station A and the radio base station B perform radio communication with each communication terminal 2 using radio signals in different frequency bands (or frequencies), and the radio base station A and the radio base station B communicate with each other. A system is configured, and the entire wireless communication system is configured by the plurality of wireless communication systems. Here, the radio base stations A and B constituting each radio communication system are shown one by one for convenience of explanation. However, each radio base station may have a plurality of radio base stations. In addition to the radio communication system by the stations A and B, more radio communication systems may exist. Further, the communication terminal 2 establishes a wireless communication connection with the wireless communication system having the wireless base station A or B and a wireless communication connection with each base station in each wireless communication system according to the radio wave strength or an instruction from the wireless base station. Thus, a process for always maintaining good wireless communication connection standby with the wireless communication system or the wireless base station is performed.

  In the process of switching the wireless communication standby destination from the wireless base station to another base station, the wireless base station is in a state of waiting for its own base station for a Global Service Redirection Message (hereinafter referred to as redirection information). By transmitting to the communication terminal 2, the communication terminal 2 that has received the redirection information performs acquisition processing for switching the connection destination of the wireless communication to another wireless base station (wireless communication system), and then the redirection after a certain time has elapsed. The communication terminal 2 that has performed the above-described processing is redirected to another wireless base station <wireless base station (wireless communication system) connected before the redirection processing, or other wireless base station (wireless communication system)>. The selection process is performed, and the standby destination is switched to the radio base station. In the present embodiment, when there is an incoming call process at the time of this reselection (when the incoming call is being received), a process for improving the incoming call rate of the communication terminal 2 is performed by giving priority to the incoming call process. . Hereinafter, the processing will be described. Note that the reselection process may not be based on the redirection process.

FIG. 2 is a functional block diagram of the communication terminal.
The communication terminal 2 accepts inputs such as a control unit 21 that controls each processing unit in its own terminal, a radio communication unit 22 that performs radio communication with a radio base station using a CDMA digital mobile communication system, and input of characters and operation instructions. A key input unit 23, an audio output unit 24 for outputting sound, a display unit 25 for displaying character strings and other information input on a liquid crystal screen, an incoming / outgoing presence / absence determining unit 26 for determining the presence / absence of an incoming call, and a reselection process. A storage unit 28 for storing various information such as a reselection processing unit 27 and a PRL (Preferred Roaming List) is provided.

FIG. 3 shows the data structure of the PRL.
Next, the PRL will be described.
The PRL is a list holding identification information of radio base stations (wireless communication systems), and is stored in advance in the storage unit 28 of the communication terminal 2. As shown in FIG. 3, the PRL includes a plurality of combination information such as BandClass (used frequency band: hereinafter referred to as BC), channel (used frequency, hereinafter referred to as CH), SID (system identifier), NID (network identifier), and priority. Is retained. Here, in order to configure different radio communication systems, different BC, CH, SID, and NID information is assigned to the radio base station A or B. And the communication terminal 2 receives the signal (pilot signal) transmitted from the radio base station, compares the information included in the signal with the information held in the PRL, and holds it in the PRL, for example. It is a signal including BC, CH, SID, and NID information, and a radio base station that transmits a signal having a radio wave intensity of a predetermined level or higher is captured. Then, the communication terminal 2 waits for information from the radio base station that has succeeded in the acquisition process toward the terminal. The priority held in the PRL indicates a radio communication base station (wireless communication system) that preferentially captures, and is indicated in the PRL with a priority “high” or “low”. For example, the priority of the communication terminal 2 when the communication terminal 2 is in a state of waiting for the radio base station of the radio communication system having the high priority is when the communication terminal 2 is used frequently. This is used for processing to make a wireless communication system with a low priority “low” stand by.

  Further, when the communication terminal 2 waits for information from the radio base station toward the own terminal, the communication terminal 2 performs the position registration process of the own terminal with respect to the radio base station that has captured it. In response to the reception of the connection start information (Sync) received from the radio base station, this location registration processing returns its own terminal identification information (terminal ID, etc.) to the radio base station, and the radio base station and management (not shown) This means that the server holds identification information of the communication terminal 2.

FIG. 4 is a diagram showing a processing flow of the communication terminal in the present embodiment.
Next, a processing flow of the wireless communication system in the present embodiment will be described using FIG.
For example, first, the communication terminal 2 that is in a standby state with respect to the radio base station B receives the redirection information from the radio base station (radio communication system) B, and then changes to the radio base station (radio communication system) A. It is assumed that the standby destination is switched and the wireless base station A is in a standby state. In such a standby state, the reselection processing unit 27 of the communication terminal 2 operates a timer until the start of reselection as the next process of the position registration process after the redirection process (step S101). Counts up to the indicated value.

  When the reselection processing unit 27 finishes counting to the timer value (a predetermined condition is satisfied) (step S102), the incoming call presence / absence determination unit 26 of the communication terminal 2 then receives an incoming call as a process before starting the reselection process The presence / absence is determined (step S103). If the incoming call processing from the radio base station A is being performed by the control unit 21 of the communication terminal 2, the incoming call presence / absence determination unit 26 determines that there is an incoming call and notifies the reselection processing unit 27 to that effect. When receiving the notification that there is an incoming call, the reselection processing unit 27 stops the subsequent reselection processing (step S104). If the incoming call processing from the radio base station A is not performed by the control unit 21 of the communication terminal 2, the incoming call presence / absence determination unit 26 determines that there is no incoming call and notifies the reselection processing unit 27 to that effect. When the reselection processing unit 27 receives a notification that there is no incoming call, it starts the subsequent reselection processing (step S105).

Next, the reselection process will be described.
When the reselection processing unit 27 starts the reselection processing, first, the reselection processing unit 27 performs acquisition processing for the radio base station. In this acquisition process, the PRL stored in the storage unit 28 is read, the identification information of the radio base station (wireless communication system) associated with the priority “high” in this PRL is identified, and this identification is performed. Information such as the used frequency band BC and the used frequency CH in the identification information is obtained, and a pilot signal transmitted from the radio base station is searched based on the used frequency band BC and the used frequency CH. Then, if the received strength of the pilot signal that has been searched (received) is equal to or higher than a predetermined level, it is determined that the search has been successful, and the short-period PN code of the terminal is synchronized with the pilot signal that has been successfully searched, Acquisition for the radio base station is performed (step S106). In the present embodiment, a radio base station (radio communication system) B is captured.

  After this synchronization is performed, the SCHM on the Sync Channel of the signal transmitted from the radio base station B is received, and the identification information (SID, NID) of the radio base station (radio communication system) B included in the SCHM ) And the acquisition priority of the radio base station (radio communication system) on the PRL for this identification information (SID, NID) is confirmed. When the radio base station (radio communication system) B that has received this SCHM is stored as the one having the highest priority on the PRL, standby for this radio base station (radio communication system) is started. . Then, the reselection processing unit 27 performs a location registration process for the radio base station B (step S107). In addition, when the priority of the captured radio base station (wireless communication system) is not set highest on the PRL, the radio base station (wireless communication system) for which the priority of the next point is set The same processing is performed, and capture processing and standby processing are performed. Further, when a radio base station (wireless communication system) for which high priority is set cannot be captured, standby at the radio base station (wireless communication system) that is currently waiting is resumed.

  With the above processing, the communication terminal determines whether or not there is an incoming call before starting the reselection, and if there is an incoming call, performs processing for giving priority to the incoming call processing. Therefore, the incoming rate can be improved. When the reselection process is completed in step S104 described above, the reselection processing unit 27 waits until the end of the incoming call process, and when the incoming call process ends, the reselection process may be started. Good.

  Note that the communication terminal and the wireless base station described above have a computer system inside. The process described above is stored in a computer-readable recording medium in the form of a program, and the above process is performed by the computer reading and executing this program. Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

  The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

  In the above-described embodiment, the communication terminal itself determines whether to start the reselection process (capture process), determines whether there is an incoming call, determines whether the reselection process can be performed, performs the reselection process, etc. The processing means for performing the processing is provided in the communication terminal, but the processing means for performing these processing is not limited to this, for example, in a communication system such as a radio base station or a management server. It may be arranged and constituted.

  In the above-described embodiment, the condition for performing the reselection process is that the elapsed time from the position registration after the redirection process is a predetermined time. However, the present invention is not limited to this. You may comprise so that a reselection process may be performed when conditions are satisfy | filled.

  In the above-described embodiment, the presence / absence of an incoming call is determined when a reselection process is started in accordance with a predetermined condition. However, the present invention is not limited to this, and an incoming call is made before the determination of the predetermined condition. If there is an incoming call (if the incoming call is received), the reselection process is restricted (stopped or suspended), and if there is no incoming call, it is determined whether a predetermined condition is satisfied. You may do it. In addition, by setting it as the structure which determines the presence or absence of an incoming call when predetermined conditions are satisfy | filled like embodiment mentioned above, the determination frequency of the presence or absence of an incoming call can be reduced and a control load can be reduced.

It is a block diagram which shows the structure of a radio | wireless communications system. It is a functional block diagram of a communication terminal. It is a figure which shows the data structure of PRL. It is a figure which shows the processing flow of a reselection process part.

Explanation of symbols

A, B radio base station 2 communication terminal 21 control unit 22 radio communication unit 23 key input unit 24 voice output unit 25 display unit 26 incoming / outgoing presence determination unit 27 reselection processing unit 28 storage unit

Claims (5)

A wireless communication system comprising a plurality of base stations and a communication terminal capable of wireless communication with any one of the plurality of base stations,
The communication terminal is
Acquisition priority storage means for storing the priority of the base station that performs acquisition;
An incoming / outgoing presence determining means for determining the presence / absence of an incoming call at the terminal;
When it is determined that the predetermined condition is satisfied when the terminal is in a standby state and the incoming / outgoing presence / absence determining means determines that no incoming call is received, the terminal is selected based on the priority stored in the capture priority storage means. Acquisition instruction means for instructing acquisition to a base station;
Acquisition processing means for performing acquisition processing to the selected base station based on the acquisition instruction;
A wireless communication system comprising: The capture instruction means
2. The capture instruction is performed after the incoming call processing is completed when the incoming call presence / absence determining unit determines that the incoming call is being received when the predetermined condition is satisfied. The wireless communication system described. A wireless communication method in a wireless communication system comprising a plurality of base stations and a communication terminal capable of wireless communication with any one of the plurality of base stations,
Storing the priority of the base station from which the communication terminal captures;
Determine whether there is an incoming call at the communication terminal,
A predetermined condition is satisfied when the communication terminal is in a standby state, and when it is determined that the communication terminal is not receiving an incoming call, an instruction to capture to the base station selected based on the priority is given.
A radio communication method, wherein the communication terminal performs acquisition processing on the selected base station based on the acquisition instruction. The communication terminal in a wireless communication system comprising a plurality of base stations and a communication terminal capable of wireless communication with any one of the plurality of base stations,
Acquisition priority storage means for storing the priority of the base station that performs acquisition;
An incoming / outgoing presence determining means for determining the presence / absence of an incoming call at the terminal;
When it is determined that the predetermined condition is satisfied when the terminal is in a standby state and the incoming / outgoing presence / absence determining means determines that no incoming call is received, the terminal is selected based on the priority stored in the capture priority storage means. Acquisition instruction means for instructing acquisition to a base station;
Acquisition processing means for performing acquisition processing to the selected base station based on the acquisition instruction;
A communication terminal comprising: A program to be executed in a wireless communication system comprising a plurality of base stations and a communication terminal capable of wireless communication with any one of the plurality of base stations,
An incoming / outgoing presence determination process for determining the presence or absence of an incoming call at the communication terminal;
When a predetermined condition is satisfied when the communication terminal is in a standby state, and when it is determined by the incoming / outgoing presence determination process that the communication terminal is not receiving, a capture priority storage unit that stores the priority of a base station that performs capture A base station is selected based on the stored priority, and a capture instruction process for performing a capture instruction to the selected base station;
Based on the acquisition instruction, acquisition processing of the communication terminal to the selected base station,
A program that executes

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