JP2007181141A - Radio apparatus and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a communication capability (communication rate) by performing roaming processing on a radio cell of a low communication load from both communication service offering-side and utilizing-side radio terminal devices in accordance with a communication load status for each radio cell. <P>SOLUTION: The radio terminal device which offers or utilizes a communication service via a wireless network on which a plurality of radio cells are formed within the identical area, acquires communication resource utilization statuses of the plurality of radio cells. Based on the acquired communication resource utilization statuses of the radio cells, a radio cell to offer or utilize a communication service is selected and negotiation of a parameter regarding roaming processing to the selected radio cell is performed. In accordance with a result of that roaming negotiation, roaming between radio cells is then performed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for performing roaming processing between wireless cells.

  Conventionally, as a technique in which a wireless terminal autonomously roams between overlapping wireless cells in response to an increase in communication traffic, for example, the technique described in Patent Document 1 is generally used. The device described in Patent Document 1 periodically transmits a communication load status for each access point (wireless base station) forming a wireless cell using a beacon (notification signal), and a wireless terminal on the receiving side communicates. It roams autonomously to an access point with a low load.

  In addition, in order to provide the communication capability (communication rate) necessary for the communication service to be used, after the start of communication, it automatically roams when it is detected that the necessary communication capability (communication rate) cannot be secured. A technique (see, for example, Patent Document 3) has also been proposed.

Furthermore, a method of switching the wireless communication interface to be used according to the communication capability (communication rate) required by the communication service to be used has been proposed (for example, see Patent Document 2).
JP 2001-298467 A Japanese Patent Laid-Open No. 9-200825 Japanese Patent Application Laid-Open No. 2004-297881

  However, in the conventional method, even if the communication service activation side wireless terminal performs roaming processing to a wireless cell with a low communication load corresponding to the communication load situation for each wireless cell, the communication capability (communication rate) is not improved. There was a problem that. For example, if the communication load of the wireless cell of the communication service passive wireless terminal is high, the wireless cell of the passive wireless terminal becomes a bottleneck, and the communication capability (communication rate) as a communication service providing system does not improve. .

  Therefore, according to the communication load status of each radio cell, the present invention performs communication roaming processing (communication rate) by performing both roaming processing on a radio cell with a low communication load on both the communication service providing side and the use side radio device. ) To improve.

  The present invention is a wireless device that provides or uses a communication service based on an acquisition unit that acquires communication resource usage statuses of a plurality of radio cells and a communication resource usage status of each radio cell acquired by the acquisition unit. A selection unit that selects a radio cell, a negotiation unit that performs negotiation on a roaming process to the radio cell selected by the selection unit with a counterpart device for providing or using the communication service, and depending on a result of the negotiation Roaming means for performing wireless inter-cell roaming.

  The present invention also relates to a method for controlling a radio apparatus, an acquisition step of acquiring communication resource usage statuses of a plurality of radio cells, and a communication service based on the communication resource usage status of each radio cell acquired in the acquisition step. A selection step of selecting a radio cell to provide or use, and a negotiation step of performing negotiation on roaming processing to the radio cell selected in the selection step with a counterpart device for providing or using the communication service, and the negotiation And a roaming step of performing roaming between wireless cells according to the result.

  According to the present invention, according to the communication load situation for each wireless cell, both the communication service providing side and the use side wireless device perform roaming processing on the wireless cell having a low communication load, thereby enabling communication capability (communication rate). ) Can be improved.

  The best mode for carrying out the invention will be described below in detail with reference to the drawings. In this embodiment, a QoS wireless LAN compliant with the IEEE 802.11e standard capable of notifying index information of the remaining communication capacity for each wireless cell (service set) is used as a communication medium of the communication path.

  In addition, the stream data distribution system of the present embodiment configures a wireless service area in which wireless cells in the QoS wireless LAN are overlapped to improve communication capability (throughput and the like). Then, based on the remaining communication capability index information, the wireless terminal roams between the wireless cells constituting the wireless service area.

[First Embodiment]
As a first embodiment, a case where a stream data distribution system is configured by a stream media server and a media renderer (display, etc.) will be described as an example. A process for automatically selecting and setting a wireless cell to be used when distributing AV (Audio, Video) stream data from a stream media server to a media renderer will be described.

  FIG. 1 is a diagram illustrating an example of a configuration of a stream data distribution system according to the first embodiment. Reference numerals 1 to 3 denote wireless access points (QAP1 to 3), which constitute a basic service set (BSS1 to 3) as a wireless cell. Reference numeral 4 denotes a wireless service area as an extended service set (ESS), which is configured by overlapping a plurality of wireless cells. Reference numeral 5 denotes a media renderer (QSTA1), which receives a high-quality video stream through an inter-terminal wireless connection (DLS) defined by IEEE 802.11e. Reference numeral 6 denotes a media server (QSTA2), which distributes a high-quality video stream through an inter-terminal wireless connection (DLS) defined by IEEE 802.11e. 7 is a media renderer (QSTA3), and 8 is a media server (QSTA4). In DLS (Direct Link Setup), direct communication is performed between terminals without passing through the wireless access point under the control of the wireless access point. For example, DLS is a wireless communication path for stream data communication between the media renderer 5 (QSTA1) and the media server 6 (QSTA2).

  Next, the functional configuration of the wireless terminal (media renderer and stream media server) in the first embodiment will be described using FIG. 2 and FIG.

  FIG. 2 is a block diagram illustrating an example of a functional configuration of the media renderer. 200 is a radio unit, 201 is a communication control unit, 202 is an AV signal processing unit that controls encoding, decoding, and format conversion of AV information, 203 is a display control unit, 204 is a display unit, 205 is a system control unit, and 206 is DLS availability A storage unit 207 is an operation unit.

  FIG. 3 is a block diagram illustrating an example of a functional configuration of the stream media server. 300 is a wireless unit, 301 is a communication control unit, 302 is an AV signal processing unit that controls encoding, decoding, and format conversion of AV information, 303 is a recording medium control unit, 304 is a recording medium, 305 is a system control unit, and 306 is DLS An availability storage unit 307 is an operation unit.

  In the above configuration, an example of simultaneous roaming behavior performed between wireless terminals in the first embodiment will be described with reference to FIGS. Specifically, this is a case where a request for distributing broadband data from the media server 8 (QSTA4) to the media renderer 7 (QSTA3) occurs. Further, a case will be described in which QSTA4 and QSTA3 are associated with a radio cell (BSS1) and roaming to a radio cell (BSS2) with a sufficient communication capability due to a shortage of the remaining communication capability of BSS1.

  The stream data distribution start operation may be performed directly from the media server 8 or may be performed by the remote control of the media renderer 7 or the like.

  4 and 5 are diagrams illustrating a sequence example when a group of wireless terminals performing stream data communication succeeds in roaming between wireless cells. FIG. 6 is a diagram showing a list of usage status for each subtype of a frame defined in IEEE 802.11e. FIG. 7 is a diagram showing the details of the QBSS Load information element from the frame format of a search request (Probe Request) and a search response (Probe Response) defined in IEEE 802.11e. FIG. 8 is a flowchart showing processing when a search response is received by the media renderer. FIG. 9 is a flowchart showing processing when a stream data communication request is generated by the media renderer. FIG. 10 is a flowchart showing processing when a media server accepts a roaming negotiation request.

  Distribution (400) of wideband stream data (HD (High Density) quality video stream) is performed from the stream media server 6 (QSTA2) to the media renderer 5 (QSTA1). In addition, an inter-terminal wireless connection (DLS) defined in IEEE 802.11e is used as a wireless communication path for stream data communication. In this state, when the above-described stream data distribution start operation is performed, the wireless access point 1 (QAP1) collects content information (411, 412) with respect to QSTA3 and QSTA4.

  The communication path between QSTA3 and QAP1 and between QSTA4 and QAP1 is a normal data communication radio communication path. The content information is information on the stream media server and communication capability information necessary for reproducing the selected content stored in the stream media server.

  Next, the QSTA 3 recognizes (410) the communication capability (HD (High Density) quality video stream) necessary for setting up a wireless communication path for stream data communication with the QSTA 4. Then, after the recognition is completed, the search request (420) is transmitted in a broadcast format, and the search response (421) is kept waiting for a certain time. After that, the QSTA 3 that has received each search response starts the processing shown in FIG.

  First, an ESS bit included in the received search response frame is extracted (S801). This ESS bit is set when the access point is building a network in the infrastructure mode. Here, it is determined whether or not 1 is set in the ESS bit (S802). If it is set, it is determined that the search response frame is received from the access point, and the other bits of the search response frame are decoded. Processing is performed (S803). Thereafter, the wireless cell identification information (SSID) is temporarily associated with the QBSS Load information (FIG. 7) indicating the communication resource usage status such as the number of radio terminals accommodated by the access point, the channel usage status, and the allowable capacity that can be used. Store (S804).

  If 1 is not set in the ESS bit, the IBSS bit included in the received search response frame is extracted (S805). This IBSS bit is set when an ad hoc mode network is constructed between wireless terminals. Here, it is determined whether or not 1 is set in the IBSS bit (S806). If it is set, it is determined that a search response frame has been received from the wireless terminal that has constructed the ad hoc network. Then, processing such as decoding other bits of the search response frame is performed (S807), and the reception processing is terminated.

  Next, the QSTA 3 refers to the identification information (SSID) of the plurality of radio cells and the “Available Admission Capacity” field information of the QBSS Load information (FIG. 7) (430, S901). This field information indicates the allowable capacity that can be used at the access point or the master station in the ad hoc mode as a percentage. That is, the remaining communication capability for each wireless cell is confirmed based on this percentage. Next, it is determined whether or not the remaining communication capability of the wireless cell (BSS1) being associated has room for stream data distribution (S902). As a result, if there is room, processing for immediately setting a communication path for stream data communication is performed (S908).

  If there is no margin in the remaining communication capability, it is determined whether there is a margin for the delivery of stream data in the remaining communication capability of other wireless cells that are not currently associated (S903). As a result, when there is no room in the remaining communication capacity of other wireless cells that are not associated, the difficulty of starting the distribution of the current stream data is recognized (S909). Then, after notifying the device application (such as a user interface) that it is difficult to start this stream data delivery, this process is terminated. Also, if there is a margin, in order to roam with the QSTA4 to the wireless cell (BSS2), negotiations with the STA4 of parameters (BSSID, channel (frequency), security information (authentication, encryption, etc.)) necessary for roaming (S904).

  On the other hand, the QSTA 4 that has received the negotiation request from the QSTA 3 confirms the presence of the stream for data communication that is already set (S1001). Here, if it exists, roaming for the new radio cell (BSS2) is rejected (S1008), and if it does not exist, the transition to the channel (frequency) in use in the designated radio cell (BSS2) continues. Confirmation is made (S1002).

  Here, when the QSTA 4 does not have the ability to shift to the channel (frequency) being used in the designated radio cell (BSS2), it rejects roaming for the new radio cell (BSS2) (S1009). If it is provided, it is confirmed whether or not it is possible to shift to the security function (authentication, encryption method) being used in the designated wireless cell (BSS2) (S1003).

  If the QSTA 4 does not have the capability to shift to the security function (authentication, encryption method) being used in the designated wireless cell (BSS2), it rejects roaming for the new wireless cell (BSS2) (S1010). In addition, if it does, roaming agreement information is returned to QSTA 3 (S1004).

  Returning to FIG. 9, when the above-described roaming negotiation (440 to 442) is completed, the QSTA 3 determines whether or not roaming to a new radio cell (BSS2) is successful (S905). As a result, if successful, a disassociate (450, 451) is transmitted to QAP1 in order to disassociate from the existing wireless cell (BSS1). Similarly to QSTA3, QSTA4 also transmits a disassociate (452) to QAP1. Then, QSTA3 and QSTA4 transmit an association (501, 502) to QAP2 in order to associate with a new radio cell (BSS2) (S906, S1005).

  Next, both QSTA3 and QSTA4 determine whether or not the association to the new radio cell (BSS2) has succeeded (S907, S1006). As a result, if it has failed, QSTA3 recognizes the difficulty in starting the distribution of the current stream data (S909). Then, after notifying the device application (such as a user interface) that it is difficult to start this stream data delivery, this process is terminated. On the other hand, the QSTA 4 notifies the existing radio cell (BBS1) of the associate roaming failure again (S1007).

  If the inter-cell roaming is successful, the QSTA 3 requests the QAP 2 to set a wireless communication path for stream data communication (510), and receives a response (512) to the request (511). Then, DLS setting (520) is performed between QSTA3 and QSTA4, and QSTA4 receives the DLS response (522) from QAP2 in response to the DLS request (521), and QSTA3 further receives (S908). Thereafter, DLS connection (530) is performed between QSTA3 and QSTA4, distribution is started (531), and stream data is distributed (532).

  Through the above processing, the communication service activation side wireless terminal determines the communication load status for each wireless cell, roams to the wireless cell with a low communication load together with the communication service passive side wireless terminal, and communicates as a communication service providing system. Capability (communication rate) can be improved.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described in detail with reference to the drawings. In the second embodiment, as in the first embodiment, when the AV stream data is distributed, the wireless media to be used is automatically selected and the setting is attempted. As a result, the stream media server side refuses roaming. The processing in the case will be described.

  FIG. 11 is a diagram illustrating an example of a configuration of a stream data distribution system according to the second embodiment. The same components as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  Distribution of wideband stream data (HD (High Density) quality video stream) from the stream media server 6 (QSTA2) to the media renderer 5 (QSTA1) is performed in the wireless cell (BSS1). In this state, the media renderer 7 (QSTA 3) newly associates with the BSS 1 and makes a distribution request for broadband data (HD (High Density) quality video stream) to the QSTA 2. QSTA3 requests media server 6 (QSTA2) to roam to BSS2, which is a new basic service set, in order to enjoy the distribution of wideband stream data. However, since QSTA2 is already delivering wideband stream data in BSS1, it refuses roaming to BSS2.

  Here, an example of roaming behavior performed between wireless terminals in the second embodiment will be described with reference to FIG. Here, when AV stream data is distributed between QSTA3 and QSTA2, simultaneous roaming to BSS2 with sufficient communication capability is attempted due to insufficient remaining communication capability of BSS1, but QSTA2 rejects roaming. is there.

  In FIG. 12, the distribution (1200) of broadband stream data between QSTA1 and QSTA2 is performed using the wireless communication path for stream data communication with the inter-terminal wireless connection (DLS) defined in IEEE 802.11e. ing. In this state, QSTA2 selects distribution of stream data (1210), and QAP1 collects content information (1211, 1212) for QSTA2 and QSTA3. Here, content information collection is performed via a wireless communication path for data communication. This content information is information on the stream media server and communication capability information necessary for reproducing the selected content stored in the stream media server.

  Next, the QSTA 3 recognizes a communication capability (HD (High Density quality video stream)) necessary for setting up a wireless communication path for stream data communication with the QSTA 2. Then, after the recognition is completed, the search request (1220) is transmitted in a broadcast format, and the search response (1221) is kept waiting for a certain time. After that, as in the first embodiment, the degree of congestion and the margin are confirmed based on the communication resource usage status of QAP1 (BBS1) and QAP2 (BBS2). When the confirmation is completed, a roaming negotiation procedure (1241, 1242) is executed.

  Here, the QSTA2 rejects the roaming request to the BSS2 (1240), performs an estimation process such as a communication rate that can be provided from the remaining communication capability of the BSS1, and notifies the information including the estimation result to the upper application of the QSTA3. . In the second embodiment, the upper application is a reproduction content selection screen display application.

  Through the above-described processing, the reproduction content selection screen display application that has received the notification reconstructs (1250) the content display that can be provided by QSTA2. Here, a selection screen (FIG. 14) is added to the normal content selection screen (FIG. 13), with a display that cannot be selected for communication capability (quality) that cannot be provided at the current provided communication speed. Therefore, a user-friendly operation interface can be provided.

[Third Embodiment]
Next, a third embodiment according to the present invention will be described in detail with reference to the drawings. In the second embodiment, the reason why the roaming request to the BSS 2 is rejected is shown as an example in which the QSTA 2 is setting a communication path for other stream data communication. However, the present invention is not limited to this. It is not a thing. In the third embodiment, the use channel of the roaming destination BSS designated by the roaming negotiation or the use security (encryption, authentication method, etc.) is designated that cannot be supported by QSTA2.

  As in the second embodiment, the sequence shown in FIG. 12 is executed, and it is recognized (1240) that the roaming request from QSTA2 to BSS2 has been rejected for the reason described above. Then, an estimation process such as a communication rate that can be provided is performed based on the remaining communication capability of the BSS 1, and information including the estimation result is notified to an upper application (here, a reproduction content selection screen display application) of the QSTA 3.

  The reproduction content selection screen display application that has received the notification by the above processing displays a display that is not selectable regarding the communication capability (quality) that cannot be provided at the current provided communication speed on the normal content selection screen (FIG. 13). The added selection screen (FIG. 14) is displayed. Therefore, a user-friendly operation interface can be provided.

[Other Embodiments]
The present invention supplies a recording medium recording a program code of software for realizing the functions of the above-described embodiments to a system or apparatus, and the program code stored in the recording medium by a computer (CPU or MPU) of the system or apparatus. Is read and executed. It goes without saying that the object of the present invention can also be achieved by this.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

  As a storage medium for supplying the program code, for example, a flexible disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, nonvolatile memory card, ROM, DVD, or the like can be used. .

  In addition, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also the following cases are included. That is, when the OS (operating system) running on the computer performs part or all of the actual processing based on the instruction of the program code, and the functions of the above-described embodiments are realized by the processing.

  Further, the program code read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. After that, based on the instruction of the program code, the CPU of the function expansion board or function expansion unit performs part or all of the actual processing, and the function of the above-described embodiment is realized by the processing. Needless to say.

It is a figure which shows an example of a structure of the stream data delivery system in 1st Embodiment. It is a block diagram which shows an example of a function structure of a media renderer. It is a block diagram which shows an example of a function structure of a stream media server. It is a figure which shows the example of a sequence when the radio | wireless terminal group which performs stream data communication succeeds in the roaming between radio | wireless cells. It is a figure which shows the example of a sequence when the radio | wireless terminal group which performs stream data communication succeeds in the roaming between radio | wireless cells. It is a figure which shows the utilization condition list for every subtype of the flame | frame prescribed | regulated to IEEE 802.11e. It is a figure which shows the detail of a QBSS Load information element from the frame format of the search request | requirement (Probe Request) and search response (Probe Response) prescribed | regulated to IEEE 802.11e. It is a flowchart which shows the process at the time of receiving a search response with a media renderer. It is a flowchart which shows the process at the time of stream data communication request generation by a media renderer. 6 is a flowchart illustrating processing when a media server receives a roaming negotiation request. It is a figure which shows an example of a structure of the stream data delivery system in 2nd Embodiment. It is a figure which shows the example of a sequence when the radio | wireless terminal group which performs stream data communication fails in the roaming between radio | wireless cells. It is a figure which shows an example of a normal content selection screen. It is a figure which shows an example of the selection screen which added the display which cannot be selected regarding the communication capability (quality) which cannot be provided with the present provision communication speed.

Explanation of symbols

1 Wireless access point (QAP1)
2 Wireless access point (QAP2)
3 Wireless access point (QAP3)
4 Extended service area 5 Media renderer (QSTA1)
6 Media server (QSTA2)
7 Media renderer (QSTA3)
8 Media server (QSTA4)
200 Radio section 201 Communication control section 202 AV signal processing section 203 Display control section 204 Display section 205 System control section 206 DLS availability storage section 207 Operation section 300 Radio section 301 Communication control section 302 AV signal processing section 303 Recording medium control section 304 Recording Medium 305 System control unit 306 DLS availability storage unit 307 Operation unit

Claims (9)

A wireless device,
Acquisition means for acquiring communication resource usage status of a plurality of wireless cells;
Selection means for selecting a radio cell that provides or uses a communication service based on the communication resource usage status of each radio cell acquired by the acquisition means;
Negotiation means for performing negotiation on roaming processing to the radio cell selected by the selection means with a counterpart device for providing or using the communication service;
Roaming means for performing roaming between wireless cells according to the result of the negotiation;
A wireless device comprising:   The radio apparatus according to claim 1, wherein the acquisition unit transmits a search request signal and acquires a communication resource usage status of each radio cell based on search response signals from a plurality of radio access points.   The wireless device according to claim 1, wherein the negotiation means notifies identification information of a roaming destination radio cell and information on a use frequency of the roaming destination radio cell.   The roaming means rejects roaming between wireless cells when a wireless communication path for data communication in an existing wireless cell is being set up on the wireless device side providing the communication service. Wireless device.   The wireless device according to claim 1, wherein the roaming means rejects roaming between wireless cells when a use channel of a roaming destination wireless cell is not supported on a wireless device side that provides the communication service.   The wireless device according to claim 1, wherein the roaming unit rejects roaming between wireless cells when the wireless device providing the communication service cannot cope with the designated security function. A method for controlling a wireless device, comprising:
An acquisition step of acquiring communication resource usage status of a plurality of wireless cells;
A selection step of selecting a radio cell that provides or uses a communication service based on the communication resource usage status of each radio cell acquired in the acquisition step;
A negotiation step of performing negotiation on roaming processing to the radio cell selected in the selection step with a counterpart device for providing or using the communication service;
A roaming step of performing roaming between wireless cells according to the result of the negotiation;
A method for controlling a wireless device, comprising:   A non-transitory computer-readable storage medium storing a program for causing a computer to execute the wireless device control method according to claim 7.   A computer-readable recording medium on which the program according to claim 8 is recorded.

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