JP5882948B2 - Wireless communication apparatus and control method - Google Patents

Description

  The present invention relates to a wireless communication apparatus and a control method.

In the wireless communication technology of a wireless communication device that passes through a base station, information necessary for reception / transmission of a wireless signal and line maintenance such as handoff as notification information that the base station notifies to all wireless communication devices in the area Necessary neighboring base station information is notified. For example, in the case of IS95 wireless communication technology, the base station notified by neighboring base station information includes a wireless class (NGHBR_BAND), a frequency (NGHBR_FREQ), and base station operation reference time information (NGHBR_PN, NGHBR_TX_OFFSET, ...). ) Etc. are included. The wireless communication apparatus receives this base station information and holds it inside, and by using this base station information, it is possible to perform base station switching for maintaining the communication line.
For reference, the handoff in the IS95 system is described in Patent Document 1.

JP 2003-189346 A

By the way, in a wireless communication technology of a wireless communication device, a broadcast information providing service (broadcast service) can be performed by simultaneously receiving a single communication line called BCMCS (BroadCast MultiCast Service) by a plurality of wireless communication devices. Proposed.
From the viewpoint of effective use of radio resources, this service can stop providing information contents, open the communication line used by BCMCS, and reuse it on a general channel when there are no users of the service It has become.

However, considering the case where a wireless communication apparatus using the BCMCS moves within the communication area of the wireless base station and hands off to another wireless base station, the conventional wireless communication technology maintains the wireless communication line. Although it is possible, the radio base station before the handoff notifies whether or not a radio service such as a broadcast service provided using a radio line is started (broadcast) at the radio base station of the handoff destination. Therefore, when the broadcast service is not started (broadcast) in the handoff destination radio base station, there is a problem that the service cannot be maintained.
For this reason, when the wireless communication device performs handoff to another wireless base station for which the broadcast service has not started (broadcast), since the wireless base station at the handoff destination has not started (broadcasted), the service start request It is necessary to give. However, there is still a problem that the broadcast service is interrupted until a service start request is given and the service is provided.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a wireless communication apparatus and a control method capable of reliably performing handoff without interrupting service.

The wireless communication apparatus according to the present invention provides a wireless communication apparatus using a broadcast / multicast service provided by the selected first base station , to the second base station in which the service is stopped . When the content corresponding to the service is requested via the first base station, the content is information from the first base station, and based on the information that the service is started in the second base station. The handoff is performed to the second base station that is started when the service is stopped .

A control method according to the present invention is a method for controlling a wireless communication apparatus, wherein a wireless communication apparatus using a broadcast / multicast service provided by a selected first base station is stopped. When content corresponding to the service is requested to the second base station via the first base station, the information is information from the first base station, and the service is received by the second base station. Based on the information indicating that the service has been started, handoff is performed to the second base station that is started when the service is stopped .

  According to the present invention, there is an effect that the handoff can be surely performed without disrupting the service.

It is a block diagram which shows the structure of one Embodiment of this invention. 2 is a flowchart showing an operation of the wireless communication system shown in FIG. It is explanatory drawing which shows the table structure of peripheral base station information. It is explanatory drawing which shows the table structure of peripheral base station information. It is explanatory drawing which shows the table structure of peripheral base station information. It is explanatory drawing which shows the table structure of the search list of a periphery base station. It is explanatory drawing which shows the table structure of the information contained in the start request message of the provision service of a periphery base station. It is explanatory drawing which shows the table structure of the information contained in the start request message of the provision service of a periphery base station. It is explanatory drawing which shows the arrangement | positioning relationship of a base station. It is explanatory drawing which shows the arrangement | positioning relationship of a base station.

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 configuration of this embodiment.
In this figure, reference numeral 1 denotes a wireless communication apparatus for performing wireless communication. Reference numeral 2 denotes a base station group composed of a plurality of wireless base stations in order to perform wireless communication with the wireless communication apparatus 1. Reference numeral 11 denotes a wireless processing unit that establishes wireless communication with the wireless base stations constituting the base station group 2 via the antenna 10. Reference numeral 12 denotes an information processing unit that performs overall control of the operation of the wireless communication apparatus 1 and performs processing of services provided using wireless communication. Reference numeral 13 denotes a storage device that stores base station information such as information for identifying a service currently being used and broadcast information including neighboring base station information broadcast from a radio base station. Reference numeral 14 denotes an input unit composed of a key panel on which dial keys, function keys, and the like are arranged. Reference numeral 15 denotes a display unit composed of a liquid crystal display or the like. Reference numeral 16 denotes a speaker, and reference numeral 17 denotes a microphone. Reference numerals 20 and 21 denote wireless base stations that constitute a communication area and communicate with the wireless communication apparatus 1. Reference numeral 22 denotes a control station for controlling the radio base station A20 and the radio base station B21 and for notifying information between the radio base stations. Reference numeral 23 denotes a content server that stores content of services provided to the wireless communication device 1.
Although only two radio base stations A20 and B21 are illustrated in FIG. 1, the control station 22 includes at least radio base stations B to G located around the radio base station A20 as shown in FIG. Is connected.
The base station group 2 is a logical name, and if the wireless base station with which the wireless communication apparatus 1 is communicating is a wireless base station A, the wireless base station A and peripheral base stations B to G of the wireless base station A Are included in the base station group 2.

Next, the structure of the service start request message for the neighboring base station information, the neighboring base station search list, and the services that can be provided by the neighboring base station will be described with reference to FIGS.
First, with reference to FIG. 3 to FIG. 5, the neighboring base station information included in the broadcast information directed to the wireless communication device 1 in the communication area by the wireless base station will be described.
FIG. 3 is a diagram showing information elements of base station information of the radio base stations B and C located around the radio base station A20. In FIG. 3, only the radio base stations B and C are illustrated, but the peripheral base station information includes base station information of the radio base stations D to G in addition to this.
Neighboring base station information according to the present invention is different from IS95 neighboring base station information in that NGHBRE_SERVICE indicating the type of service that can be provided by the radio base station and NGHBRE_SERVICE_TYPE indicating the status of this service are added. It is a point.
FIG. 4 is a diagram showing a bit configuration of NGHBRE_SERVICE shown in FIG. NGHBRE_SERVICE is 7-bit information, and the type of service can be determined by the bit position.
FIG. 5 is a diagram showing a bit configuration of NGHBRE_SERVICE_TYPE shown in FIG. NGHBRE_SERVICE_TYPE is 8-bit information, and it is possible to determine the service state by the bit position.

Next, referring to FIG. 6, the wireless communication device 1 is based on the neighboring base station information included in the notification information notified by the wireless base station with which the wireless communication device 1 is currently communicating (connected). A search list of neighboring base stations generated inside 1 and stored in the storage device 13 will be described.
FIG. 6 is a diagram illustrating a structure of a search list of neighboring base stations generated in the wireless communication device 1.
As shown in this figure, the base station search list includes base stations B to G located around the base station A20 that is currently communicating based on the base station information received by the wireless communication device 1. Information relating to (No corresponds to 1 to 6) is stored. In FIG. 6, “service” is information that can determine the type of service at the bit position, and “service_type” is information that can determine the state of the service at the bit position.

Next, referring to FIGS. 7 and 8, a service start request message for requesting the neighboring radio base station of the radio base station with which the radio communication apparatus 1 is currently communicating to start the service currently used. The information contained in is described.
FIG. 7 is a diagram illustrating a structure of information included in a service start request message for starting a service of a peripheral radio base station, which is transmitted to a radio base station currently performing communication.
This information includes a service type (ACTIVATE_SERVICE) for requesting the start of service for each peripheral radio base station.
FIG. 8 is a diagram illustrating a structure that defines a service type for which a start is requested.
The service type (ACTIVATE_SERVICE) is 8-bit information, and the service type can be determined by the bit position.

  In the following description, it is assumed that the wireless communication apparatus 1 exists in the communication area of the wireless base station A20 in the environment shown in FIG. The wireless communication device 1 uses the broadcast service provided by the wireless base station A20, and at this time, sets the value of the service information flag InuseServ held in the wireless communication device 1 to “00000001” (broadcast service).

Here, a basic operation in the wireless communication apparatus 1 will be briefly described.
The wireless communication apparatus 1 generates a neighboring base station search list Neiber from neighboring base station information (including service information) included in the broadcast information broadcast from the wireless base station, and registers it in the storage device 13. In addition, the wireless communication device 1 holds the service currently used in the service information flag InuseServ. The wireless communication device 1 determines a wireless base station that can use a service by using the following equations (1), (2), and (3) at each radio wave state measurement timing of a surrounding wireless base station. Only radio base stations that can use the radio field strength measurement.

Based on the service information flag InuseServ of the currently used service, the wireless communication apparatus 1 determines whether or not this service can be used in the wireless base station group located around the wireless base station currently communicating (1 Judgment is made according to the equation
(InuseServ & Neiber [i] .service) = InuseServ (1)
Here, “&” means a logical product for each bit, [i] indicates the i-th radio base station, and Neiber [i] .service indicates the value of “service” shown in FIG. . Therefore, if the expression (1) is “true”, it can be confirmed that the same service as the service currently provided can be used.

On the other hand, if the expression (2) is “true”, it indicates that the j-th radio base station cannot provide the same service as that currently used by the radio communication apparatus 1.
(InuseServ & Neiber [j] .service) ≠ InuseServ (2)
The wireless communication device 1 can narrow down handoff destination candidates based on the determination formulas (1) and (2).

When the wireless communication device 1 determines that the radio wave intensity from the surrounding wireless base station B21 is stronger than the wireless base station A20 that is currently communicating when the handoff occurs, the wireless base station of the handoff destination from the equation (3) In the station B21, it is determined whether or not the same service as the service currently used is started (broadcast).
(InuseServ & Neiber [i] .serviceType) = InuseServ (3)
Here, Neiber [i] .serviceType means the value of “service_type” shown in FIG. When this expression is “true”, it can be confirmed that the same service as that currently used by the wireless communication apparatus 1 is started (broadcasted) in the wireless base station B21. For this reason, since service interruption due to handoff does not occur, the wireless communication device 1 can start a handoff operation to the wireless base station B21.
On the other hand, when this expression is “false”, the radio base station B21 can confirm that the service is stopped. Therefore, the wireless communication device 1 transmits a service start request for the wireless base station B21 to the wireless base station A20 that is currently connected (receives neighboring base station information). The radio base station A 20 transmits a service start request for the radio base station B 21 to the control station 22. The wireless communication device 1 confirms that the desired service is started in the wireless base station B21 based on the notification information broadcast from the wireless base station A20, and the wireless communication device 1 performs handoff to the wireless base station B21. Start.

Next, the operation of the wireless communication apparatus 1 shown in FIG. 1 will be described with reference to FIG.
First, the radio processing unit 11 receives neighboring base station information (FIG. 3) included in the broadcast information broadcast from the radio base station A20 (step S1). The wireless communication device 1 generates a peripheral base station search list (FIG. 6) based on the peripheral base station information, and stores the peripheral base station search list in the storage device 13. Since the neighboring base station information is notified at regular intervals, the information processing unit 12 updates the neighboring base station search list every time this information is received.
Subsequently, the wireless processing unit 11 measures the signal strength of the wireless communication base station A20 that is currently communicating (step S2), and determines whether or not the signal strength of the received signal has decreased. As a result, if the signal strength is not lower than a certain signal strength, it is determined that the handoff is unnecessary, and the process returns to step S1 to continue the processing.
On the other hand, when the received signal strength is lower than a certain signal strength, the information processing unit 12 determines that it is necessary to perform handoff, and refers to the neighboring base station search list stored in the storage device 13. (Step S3) Among the surrounding base stations, a list of neighboring base stations that can use the service currently used by the wireless communication device 1 is created (Step S4).
Next, the wireless communication device 1 measures the signal strength from the peripheral base stations registered in the peripheral base station list, and selects a peripheral base station capable of handoff. As a result, a peripheral base station (in this case, wireless base station B) that is a handoff candidate is selected. If there is no wireless base station that is a candidate for handoff (no base station that provides the same service), communication is continued without performing handoff.

On the other hand, when a wireless base station that is a candidate for handoff is found (when there is a base station that provides the same service), the service currently used by the terminal at this wireless base station is started (broadcasted) at this time. It is determined whether or not (step S5).
If the service is started (broadcast), the information processing unit 12 instructs the wireless processing unit 11 to start a handoff operation. In response to this, the wireless processing unit 11 performs handoff (step S6).
On the other hand, if the service can be provided (started), but the service is not started at the present time (if it is stopped), the information processing unit 12 passes the wireless processing unit 11 to the radio base station A20. On the other hand, a service start request is transmitted (step S7). Receiving this service start request, the radio base station A20 instructs the radio base station B21 to start the service via the control station 22. Upon receiving an instruction from the control station 22, the radio base station B21 starts providing the requested service.

The operation shown in FIG. 2 will be described with a specific example.
When the wireless communication device 1 moves, the strength of the received signal from the wireless base station A20 decreases, and the strength of the signal from the wireless base station B21 increases, the wireless communication device 1 performs a handoff to the wireless base station B21. For the preparation, the service provision status is confirmed with reference to the neighboring base station search list (FIG. 6) stored in the storage device 13. At this time, the service information of the radio base station B is No. In the case of 1, since “service” is “0000111” and “service_Type” is “0000100”, the radio base station B can provide (start) the broadcast service, but is currently stopped. Can be obtained (see FIG. 10). The wireless communication apparatus 1 transmits a service start request message shown in FIGS. 7 and 8 to the wireless base station A20 in order to validate (start) the broadcast service of the wireless base station B. The radio base station A20 transfers this service start request message to the radio base station B21 via the control station 22.
In response to this, the radio base station B21 starts a broadcast service. When the wireless communication device 1 receives the broadcast information transmitted from the wireless base station A20 and confirms that the broadcast service is started in the wireless base station B21, the wireless communication device 1 performs a handoff operation from the wireless base station A20 to the wireless base station B21. Start.

  As described above, in the broadcast information broadcasted by the wireless base station to all wireless communication devices in the area, information on services that can be provided by neighboring wireless base stations, and this wireless service is currently started (broadcast) or stopped. In the case of performing handoff by including service state information such as being in the middle, the wireless communication device 1 refers to the service information notified by the wireless base station and the state information of the service, and the current wireless base station at the handoff destination The handoff operation is performed only when the service being used can be provided and started (broadcasted). As a result, the handoff can be surely performed without interrupting the service. In addition, when the service currently being provided is stopped at the handoff destination radio base station, the start request for the same service as the service currently being used is transmitted to the handoff destination radio base station. Even when the handoff destination service is stopped, the handoff can be surely performed without interrupting the use of the service.

  The wireless communication device of the present invention includes a mobile phone using mobile communication, a personal digital assistant (PDA) having a mobile communication function, a mobile terminal, a car navigation device, and the like.

  A program for realizing the function of the processing unit in FIG. 1 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed to perform handoff processing. May be. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Further, the “computer-readable recording medium” refers to a volatile memory (RAM) in a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In addition, those holding programs for a certain period of time are also included.

  The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. 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.

  DESCRIPTION OF SYMBOLS 1 ... Wireless communication apparatus, 10 ... Antenna, 11 ... Wireless processing part, 12 ... Information processing part, 13 ... Memory | storage device, 14 ... Input part, 15 ... Display part, 16 ... Speaker, 17 ... Microphone, 2 ... Base station group 20 ... wireless base station A, 21 ... wireless base station B, 22 ... control station, 23 ... content server

Claims (2)

A wireless communication apparatus using a broadcast / multicast service provided by the selected first base station sends content corresponding to the service to the second base station whose service is stopped . If requested through one base station, it is information from the first base station, and based on the information that the service has been started in the second base station, the service is started after being stopped. A wireless communication apparatus that performs handoff to the second base station . A method for controlling a wireless communication device, comprising:
A wireless communication apparatus using a broadcast / multicast service provided by the selected first base station sends content corresponding to the service to the second base station whose service is stopped . If requested through one base station, it is information from the first base station, and based on the information that the service has been started in the second base station, the service is started after being stopped. A control method comprising performing handoff to the second base station .

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