WO2007066577A1

WO2007066577A1 - Radio communication system, and radio communication method

Info

Publication number: WO2007066577A1
Application number: PCT/JP2006/323988
Authority: WO
Inventors: Hisao Kumai; Suguru Toyokawa; Toru Sugayama
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2005-12-08
Filing date: 2006-11-30
Publication date: 2007-06-14
Also published as: JPWO2007066577A1; JP4657305B2

Abstract

Provided are a radio communication system, in which the switching of a transmission line and the switching of an application according to the change, as accompanying the movement of a user in a mobile environment, in communication situations are associated with each other, and a radio communication method. The change, as accompanying the movement of the user, in the data transfer quality of the transmission line being used is always monitored, and the transmission line is switched according to the change in the data transfer quality of the transmission line. When the change in the data transfer quality is to be judged, the judgment of the switching of the transmission line is facilitated by using the priority criterion of the transmission line for selecting the transmission line being used and the transmission line state between the user's terminal and the communication partner terminal. As a result, it is possible to provide services according to the communication situations.

Description

Specification

Wireless communication system and wireless communication method

Technical field

[0001] The present invention is used in a mopile network system using communication terminals having a plurality of wireless communication means, and provides a communication program for communicating via a plurality of networks, and a conversation-type and streaming-type application service to users. The present invention relates to a wireless communication system and a wireless communication method.

Background technology

[0002] With the recent advances in wireless technology, connections to the Internet using various wireless communication methods have become widespread, and a mopile communication environment in mobile environments is being provided by taking advantage of the advantages of wireless. It is becoming. Additionally, mobile terminals are becoming more sophisticated, and a single terminal device can now connect to multiple networks (e.g., wireless LAN (Local Area Network), wired LAN, mobile phone, PHS (Personal Handy phone System, etc.)). This has made it possible to connect to multiple types of networks with one terminal device, and it has become possible to select the most suitable communication environment for communication each time it is used. It's coming.

[0003] Furthermore, with the advent of technologies that enable continuous wireless communication between different networks (Mob ile IPv6, Lin6, etc.), the optimal communication environment can be selected each time the communication is switched. It is becoming possible to receive services without interruption. Furthermore, a technique has been proposed that changes the quality of received data in response to changes in communication status due to switching of networks for wireless communication (see, for example, Patent Document 1).

[0004] On the other hand, a method has been proposed in which a quality of service level is defined and the quality of service level is selected according to the communication quality of the network, and multimedia data is transmitted and received according to the selected quality of service level. (See Patent Document 2).

Patent document 1: Japanese Patent Application Publication No. 2004-272563

Patent document 2: Japanese Patent Application Publication No. 2004-112789

Disclosure of invention

The problem that the invention seeks to solve [0005] However, in the technology disclosed in Patent Document 1, the communication state (transmission path state between communication terminals) for selecting a network interface is only set in advance. Although it is possible to obtain the effective transfer speed of the network interface currently in use after communication starts, the data of the currently used transmission path is higher than that of other communicable transmission paths. Even if the transfer quality deteriorates, it is not possible to judge the situation. Furthermore, as mentioned above, if the data transfer quality deteriorates, consideration is given to reviewing the priorities of the available transmission paths and switching to the transmission path with the highest priority under the current communication conditions.

[0006] Furthermore, the technology disclosed in Patent Document 2 selects a service quality level based on the effective transfer rate of the transmission path in use, and provides a service according to the transmission path status. However, when there are multiple available transmission paths, it is difficult to obtain the status of each transmission path under multiple transmission path conditions, or to respond to changes in the status of transmission paths that are not in use. Switching the transmission line has been considered.

The present invention provides a wireless communication system and a wireless communication method for efficiently solving the various problems described above.

Means to solve problems

[0007] The wireless communication system of the present invention is a wireless communication system in which a communication terminal equipped with a network interface connectable to a plurality of transmission paths uses a plurality of transmission paths. Detects a communicable network interface among the interfaces, acquires network interface information regarding predetermined attributes of multiple network interfaces, and connects the communicable network interface with the communicable network interface of the communication partner. Create a list of transmission paths existing in the transmission path list, obtain information regarding the status of the transmission path corresponding to the transmission path list, and set the priority of the transmission path based on either the network interface information or the transmission path information. data communication via the determined transmission path. Then, after starting data communication, changes in the data transfer quality of the transmission path in use are detected and the transmission path is switched.

[0008] That is, the wireless communication system of the present invention is a wireless communication system in which a communication terminal equipped with a network interface connectable to a plurality of transmission paths uses a plurality of transmission paths, The feature is that the application program or the user side monitors the data transfer quality of the transmission path in use and switches to a higher priority transmission path other than the one in use to perform communication. A means for detecting a change in the data transfer quality state described above should be provided in the application program, and a means for allowing the user to decide whether to switch the transmission path after detecting a change in the data transfer quality state should be provided. Sorry,.

[0009] The above-mentioned change in the state of data transfer quality is based on the data transfer quality measured using packets during data communication and the transmission path information of the transmission path selected according to the priority of the transmission path determined in advance. It is detected by comparing it with a threshold value. Alternatively, the data transfer quality measured using packets during data communication may be compared with a preset threshold.

In addition, the transmission path to be switched to must be the transmission path with the next highest priority after the transmission path currently in use, or the transmission path that is to be switched to is the transmission path that has the next highest priority after the transmission path currently in use, or the transmission path that is to be switched to is a transmission path that has the second highest priority after the transmission path currently in use. By acquiring the transmission path information, it is possible to select the transmission path with the highest priority.

[0010] Furthermore, as a threshold value for determining the deterioration of the transmission path condition, the priority of the transmission path determined based on the transmission path condition and the priority criteria is set to the next highest priority after the transmission path currently in use. High You may also compare it with the transmission line condition of the transmission line. Regarding data transfer quality, we calculate the one-way delay amount calculated from the sending and receiving times of data packets, the number of retransmitted packets of transferred data for which retransmission is requested after detecting discontinuity in sequence numbers, and the number of packet losses from sequence numbers. Information such as the packet loss rate, which is confirmed and calculated, and the effective bandwidth of the transmission path, which is calculated from the data size received over a certain period of time, is targeted.

[0011] Furthermore, the above network interface information includes communication conditions detected in layers lower than the transport layer, and for example, different network interface transmission speeds are used for uplink and downlink. The above transmission path information includes the bottleneck physical bandwidth, available bandwidth, RTT, and communication cost between a network connected to multiple network interfaces and the communication partner. The priority of the transmission path is determined based on the priority criteria set for each application program that performs data communication. In addition, up

If an asymmetric communication network with different downlink transmission path characteristics is included, different transmission paths can be selected for uplink and downlink depending on the priority criteria. Requested bandwidth is used as priority criterion In this case, multiple requested bandwidths are set for each application program.

In addition, after data communication, if the status of the network interface that is not currently communicating, the data transfer quality of the transmission path used, the wireless modulation method, etc. change, the priority of the transmission path is reevaluated and the priority of the transmission path is changed. Switch to transmission line.

Effect of the invention

[0012] According to the present invention, an application that uses communication such as video and audio in a network system including mobile terminals equipped with multiple network interfaces in a communication environment that changes every moment as users move. When performing data communication, the application program monitors the data transfer quality of the transmission path in use during data communication, and the transmission path can be selected or switched based on the judgment of the application or the user. becomes possible.

[0013] The above judgment is based on the priority criteria set for each application program or the user's preferences.In addition, by selecting content with a quality that matches the network information, the location where the communication terminal is located It becomes possible to provide quality services according to the customer's needs. In addition, even if the status of the transmission path changes after starting data communication or when it is not in use, the status of the transmission path is acquired again and the transmission path is re-established according to the priority criteria set for each application program or the user's preferences. By making this selection, it is possible to provide services with the optimal quality for the communication environment of the location where the communication terminal is located, even in a communication environment that changes from moment to moment.

Brief description of the drawing

[0014] FIG. 1 is a diagram showing an example of the overall configuration of a network to which this embodiment can be applied.

[Figure 2] A conceptual diagram of base stations and corresponding accessible areas of a wireless network to which this embodiment can be applied.

FIG. 3 is a functional block diagram showing an example of the internal configuration of a communication terminal according to the present invention.

FIG. 4 is an operation sequence diagram showing the operation of each part of the communication terminal when communication starts.

[Figure 5] A sequence diagram showing the operation of each part when the communication status of the network interface card of the communication terminal changes.

[Figure 6] Operation of each part when the data transfer quality of the transmission path during communication of the communication terminal changes FIG.

[Figure 7] A diagram showing an example of a network interface information table in this embodiment.

[Figure 8] A diagram showing an example of a communication information notification format (A), an example of a quality information table (B), and an example of items of an application priority criteria table (C) in the present embodiment.

[Figure 9] A diagram showing an example of a network interface list (A) and an example of a transmission path list (B) in this embodiment.

FIG. 10 is a diagram showing an example of a transmission path information table in this embodiment.

[Figure 11] A diagram showing an overview of the bottleneck physical bandwidth (A) and an example of a method for measuring the bottleneck physical bandwidth (B) in this embodiment.

FIG. 12 is a diagram showing an example of a method for measuring an RTT delay difference in this example.

[Figure 13] A diagram showing an overview of available bandwidth in this embodiment.

[FIG. 14A] A flowchart showing an example of a process procedure for selecting a transmission path in this embodiment.

FIG. 14B is a flowchart showing an example of a processing procedure subsequent to FIG. 14A.

[Figure 15] FIG. 15 is a diagram showing an example of a case where different transmission paths are selected for uplink and Z-downlink in this embodiment.

FIG. 16 is a diagram showing another example of the network interface information table (A) and another example of the transmission path information table (B) in the present embodiment.

[Figure 17] A diagram showing another example of the application priority criteria table in this embodiment.

[Figure 18] Another example of network interface information to be notified (A), an example of a list of added transmission paths (B), and another example of network interface information to be notified (C) in this embodiment. FIG.

FIG. 19 is a diagram showing an example (A) of a transmission path quality table to be notified and an example (B) of a transmission path switching request in this embodiment.

FIG. 20 is a diagram explaining retransmission control.

FIG. 21 is a diagram illustrating a one-way delay amount. FIG. 22 is a diagram showing an example of a screen prompting the user to make a decision to switch the transmission path in this embodiment.

Explanation of symbols

[0015] 10... Communication terminal, 11... Application section, 12... User setting section, 13... Content control section, 14... Communication control section, 15... Information transmission section, 16... ·Transmission quality measurement unit, 17···Application priority standard table, 18···Quality information table, 19···Transmission path control unit, 20···Transmission path management unit, 21···Transmission path selection unit, 22 —IP control unit, 23...Transmission path information table, 24...Network interface information table, 25...Transmission path status management unit, 26·Network interface management unit, 27...Network interface card (NIC ), 28...Transmission path quality table, 29...Self terminal, 30...Communication partner terminal, 31...Network.

BEST MODE FOR CARRYING OUT THE INVENTION

[0016] First, the overall configuration of a wireless network to which a wireless communication system according to the present invention is applied and its accessible area will be explained with reference to FIGS. 1 and 2.

In Figure 1, networks l to n are network segments such as LAN and WAN. For example, network 1 may include multiple wireless base stations, and network 2 may include multiple wireless access points (APs). I can do it. That is, each of the networks l to n is, for example, a public mobile phone network, a private premises wireless LAN, a hotspot, or a home wireless network, and here, an IP-based network is used. Suppose there is. The networks of each of these network segments are connected to a core network represented by the Internet.

[0017] The communication terminals l to n perform communication such as video and audio communication one-to-one or between multiple terminals. For example, even if communication terminal 1 moves and changes its state from receiving radio waves from radio base station 1 to receiving radio waves from radio base station 2, there will be no communication between radio base stations 1 and 2. This allows communication terminal 1 to continue the same communication as before the move even after the move. The same applies to the connection range of wireless access point API when moving to the connection range of wireless access point AP2. Handover between wireless access points may be used in conjunction with handover of authentication information.

[0018] Furthermore, even if a communication terminal moves between network segments, handing at the network layer An override is performed and communication can continue. For example, assume that the communication terminal 2 moves and changes from being connected to the wireless base station 2 to being connected to the wireless access point API. Even in this case, the communication terminal 2 is equipped with a network interface card (NIC) that can be connected to the wireless base station 2 and the wireless access point API, and the IP control unit function described later is used. If it is compatible with Mopile IP (IETF: Internet Engineering Task Force) RFC3775, the application section will be able to continue communication processing even if it has moved to a different network.

[0019] Regarding handover between network segments, the IP control section supports Lin6 (IETF Dm ft— Teraoka— ipng— Lin6— 01), the communication control section supports handover while maintaining the session, and so on. It may also be a technology that achieves a similar function. Furthermore, regarding movement between network segments, even if wireless access point API and wireless access point AP2 are configured in different network segments, handover technology between the wireless access points described above can be used. This makes it possible to continue communicating even during downtime.

[0020] FIG. 2 is a conceptual diagram of a wireless base station, a wireless access point, and the corresponding accessible area. In Figure 2, networks 1 to 3 are network segments such as LAN and WAN, and mobile base station 1 is connected to network 1, wireless AP 2 is connected to network 2, and PHS base station 3 is connected to network 3. . The networks for each of these network segments are IP-based networks, and as in Figure 1, each network is connected to the core network.

[0021] Regarding each accessible area, mobile base station 1 corresponds to mobile area 1, wireless A P2 corresponds to wireless LAN area 2, and PHS base station 3 corresponds to PHS area 3. , the communication terminal 1 can communicate using each wireless communication method. Communication terminal 1 is equipped with a NIC that can be connected to mobile base station 1, wireless AP 2, and PHS base station 3, and in wireless LAN area 2, it is connected to mobile base station 1, wireless AP 2, and PHS base station 3 via It is possible to connect to networks 1 to 3.

[0022] Similarly, in mobile 'PHS area 4, each It is possible to connect to networks 1 and 3 via mobile base station 1, and as mentioned above, in areas other than mobile area 1 and mobile PHS area 4, it is possible to connect only to network 1 via mobile base station 1. In areas excluding mobile PHS area 4 from PHS area 3, it is only possible to connect to network 3 via PHS base station 3. For example, when communication terminal 1 moves to wireless LAN area 2 and is connected to network 2 via wireless AP 2, it also moves to mobile phone PHS area 4 and connects to network 3 via PHS base station 3. In such cases, the communication will be moved between network segments, so it is possible to continue communication by applying technologies such as the Mopile IP mentioned above.

[0023] If network 1 is selected as more suitable depending on the application used by communication terminal 1, it is also possible to connect to network 1 via mobile base station 1. Similarly, in mobile PHS area 4, if you move to mobile area 1 where you can only connect to mobile base station 1, you can connect to network 3 via PHS base station 3. Even if a device that is connected to network 1 via base station 1 moves to PHS area 3, where it can only connect to PHS base station 3, communication can be continued by applying technologies such as Mopile IP mentioned above. It is possible.

[0024] Furthermore, in wireless LAN area 2, it is possible to connect to networks 1 to 3 via mobile base station 1, wireless AP 2, and PHS base station 3, so a suitable network is selected depending on the application being used. Here, we will talk about mobile and PHS wireless LAN as wireless communication methods!/, but we will also discuss IP-based technologies such as Bluetooth, which is a short-range communication method, and IMT (International Mobile Telecommunication)—2000, which is a broadband mobile communication method. Please use any wireless communication method as long as it can provide a network.

[0025] The forms of communication are as follows: 1) The sending side is a mobile communication terminal and the receiving side is a fixedly connected communication terminal; 2) The sending side is a fixedly connected communication terminal and the receiving side is mobile. 3) Both the sending and receiving sides of the communication may be mobile communication terminals (Communication Terminals 1 and 2). In these cases, by applying the present invention to communication terminals on the transmitting side and the receiving side, applications can be controlled in accordance with switching of transmission paths. [0026] Next, embodiments according to the present invention will be described. FIG. 3 is a functional block diagram showing an example of the internal configuration of a communication terminal according to the present invention, FIG. 4 is a diagram showing an operation sequence at the start of communication, and FIG. 5 is a diagram showing an operation sequence when the communication status of the network interface card changes. , FIG. 6 is a diagram showing the operation sequence when the data transfer quality of the transmission path in use changes.

In the figure, 10 is a communication terminal, 11 is an application section, 12 is a user setting section, 13 is a content control section, 14 is a communication control section, 15 is an information transmission section, 16 is a transfer quality measurement section, and 17 is an application section. Priority standard table, 18 is quality information table, 19 is transmission path control section, 20 is transmission path management section, 21 is transmission path selection section, 22 is IP control section, 23 is transmission path information table, 24 is network interface Information table, 25 is the transmission path status management section, 26 is the network interface management section, 27 is the network interface card (NIC), 28 is the transmission path quality table, 29 is the own terminal, 30 is the communication partner terminal, 31 is the network vinegar.

[0027] The communication terminal 10 used in the wireless communication system of the present invention includes an application unit 11 that transmits, receives, and processes actual communication data, a network interface card 27, and a transmission unit that manages and controls the state of the transmission path. It is composed of a road control section 19. Note that the communication terminal 10 may be a mobile phone terminal, a PDA (Personal Digital Assistance) or a personal computer that can be connected to a wireless network, as long as it is equipped with multiple wireless communication means.

[0028] The application unit 11 is included in the application program, receives a service start request from the user, and sends application request information to the transmission path control unit 19 based on the service definition information and the application priority criteria table 17. Send. The transmission line control unit 19 is included in the application program or is used by the application program. The transmission path control unit 19 receives the application request information from the application unit 11, and manages the application request information from the application unit 11, the network interface information obtained by the network interface management unit 26, and the transmission path state management. Based on the transmission path information obtained by section 25, transmission path selection section 21 determines a transmission path. [0029]Furthermore, the transmission path selection section 21 sends information regarding the selected transmission path to the application section 11. Upon receiving this information, the content control unit 13 refers to the quality information table 18 to determine the content, and the communication control unit 14 sends and receives data to provide the service.

[0030] In addition, the transfer quality measurement unit 16 measures the effective bandwidth of the transmission path, the amount of delay in transferred data, the bucket tross rate, the amount of one-way delay, the number of retransmitted packets, etc. sends feedback of the transfer quality to the terminal, and receives notification Z of the content quality determined by the content control unit 13. Note that each part of the communication terminal may be realized by hardware, software, or a combination of these.

[0031] Next, each part of the communication terminal described above will be explained in more detail. The network interface management unit 26 manages the network interface card (hereinafter referred to as NIC) 27 provided in the communication terminal 10 and monitors its status. The network interface management unit 26 registers the information acquired regarding the NIC 27 (for example, transmission speed (standard value), charge, IP address, communication card standard, MTU (Max Transfer Unit), etc.) in the network interface information table 24. .

[0032] The network interface management unit 26 monitors the status when a new NIC is added or removed from the communication terminal 10, or when it becomes usable or unusable, and constantly updates the network interface information. Update table 24. An example of the network interface information table 24 is shown in FIG. The network interface management unit 26 obtains the items shown in FIG. 7 from the NIC device information each time the state of the NIC changes.

[0033] The transmission path state management section 25 detects a transmission path (path) that can be used with the communication partner based on the NIC information acquired by the network interface management section 26. Furthermore, the transmission path status (for example, bottleneck physical bandwidth, available bandwidth, RTT delay difference, packet loss rate, etc.) is acquired for each detected transmission path and is registered in the transmission path information table 23. Additionally, whenever the NIC information is updated, the path is detected and the transmission path information is obtained. However, in the case of the above process, newly acquire transmission path information only for the updated path. [0034] The transmission path management section 20 uses the transmission path information acquired by the transmission path state management section 25 and the application request information (for example, requested bandwidth, requested delay, fee, priority transmission path, etc.) received from the application section 11. ), select the most suitable transmission path for the application program. As a result of the selection, one transmission path that is most suitable for the application program may be selected, or the communication partner may select the transmission path based on the priority order of the transmission path. After selecting a transmission path, the transmission path status (bandwidth, delay, packet loss rate, charge, etc.) of the selected transmission path and the transmission path with the second highest priority is returned to the application section 11.

[0035] The content control unit 13 refers to the quality information table 18 based on the transmission path status notified by the transmission path management unit 20, and selects content types that can be transmitted and received. The content type here refers to, for example, the video/audio bit rate, codec type, angle of view, frame, etc. in video streaming, and the codec type in VoIP (Voice over Internet Protocol). The transmission path status notified at the same time is registered in the transmission path quality table 28.

[0036] The information transmission unit 15 starts providing the service after negotiating with the communication partner to transmit and receive data of the content type selected above. It also sends and receives application information (standby port number, usable codec types, etc.) with the communication partner. By sending and receiving the above information, it becomes possible to standardize the quality of service that can be provided by applications.

[0037] The transfer quality measurement unit 16 measures the effective bandwidth of the transmission path, the amount of delay of transferred data, the packet loss rate, the amount of one-way delay, the number of retransmitted packets of transferred data, etc. These values are compared with arbitrary thresholds set in advance, and if the thresholds are exceeded, the content control unit 13 is notified that the thresholds have been exceeded. Here, data specific to the application program (video quality, audio quality, etc.) may be used as the data transfer quality.

[0038] The user setting section 12 is an input/output section through which the user configures the communication terminal, sets the application priority standard table 17, and operates the quality information table 18. This user setting section 12 is composed of a screen, buttons, mouse, etc., and the functions of the application section 11 are controlled by user power and by executing commands specified.

[0039] The IP control unit 22 sets the address information necessary to transmit data to the IP network (Figs. 1 and 2), and sends and receives the created data to the actual network via the NIC 27. believe The communication terminal 10 is connected to the network and can be moved while maintaining the network connection.

[0040] In the communication terminal 10 described above, when the communication terminal is activated, the network interface management unit 26 collects information regarding attributes of multiple network interfaces (for example, communication card name, transmission speed, radio field strength, link status). , modulation method, etc.). Detect network interfaces that can communicate at the same time and register them in the network interface information table 24. Examples of methods for detecting the network interface include determination by comparing radio field strength with a threshold value, and changes in link status.

[0041] After the communication terminal 10 is started, the network interface management unit 26 monitors addition/deletion of network interfaces and communication enable/disable, detects changes in status, and updates the network interface information table 24 one by one. Update. When application communication starts, the communication terminal 10 acquires information on available content by notifying each other of the available content information with the communication partner, registers the information in the quality information table 18, and registers the information set in advance. It is registered in the application priority criteria table 17 along with information on application priority criteria (required bandwidth, minimum required bandwidth, allowable delay, etc.).

[0042] Next, with reference to the network interface information table 24, information on NICs with which communication is possible is sent to the communication partner. The receiving communication terminal refers to the sent NIC information and its own network interface information table 24 to extract the transmission path (path) that exists between the communication terminals. The transmission path status (bottleneck bandwidth, RTT delay difference, etc.) of each extracted path is acquired and registered in each transmission path information table 23.

[0043] The transmission path selection unit 21 selects the transmission path most suitable for the request of the application program by filtering the data in the transmission path information table 23 using the application priority criteria table 17. For example, when video streaming is started as an application program, bandwidth is set as a priority criterion, so the transmission path with the widest bandwidth is selected. At this time, it is also possible to select NICs with different uplink and Z-downlink transmission paths depending on the priority criteria. In addition, the transmission path selection unit 21 does not select one transmission path, but rather assigns a relative priority to the transmission path, notifies the communication partner of the priority, and allows the communication partner to decide the transmission path. It is also possible. [0044] When a transmission path is selected, the transmission path selection unit 21 refers to the transmission path information table 23 and transmits the transmission path information of the selected transmission path to the content control unit 13. The content control unit 13 determines the content quality from the quality information table 18 based on the received transmission path information. The information transmission unit 15 transmits the quality information of the determined content to the communication partner and starts transmitting and receiving data, and at the same time, the IP control unit 22 switches to the transmission route selected by the transmission route selection unit 21. .

By executing the above processing, data communication of the selected content is performed via the determined transmission path, and switching of the transmission path and interlocking of applications are realized.

[0045] During data communication, the transfer quality measuring unit 16 measures the transfer data quality (effective bandwidth of the transmission path, delay amount of transfer data, packet loss rate, one-way delay amount, number of retransmitted packets of transfer data, application program specific quality information, etc.) and detect changes in status. The data transfer quality obtained from the data being communicated is compared using the transmission path information of the transmission path selected according to the determined priority of the transmission path as a threshold. If the quality of transferred data falls below the threshold registered in the transmission path quality table 28 in the communication control unit 14, a transmission path switching request is notified to the content control unit.

[0046] Transmission path selection section 21 receives the transmission path switching request, notifies IP control section 22 of the requested transmission path information, and causes IP control section 22 to switch to the requested transmission path. At the same time, the quality corresponding to the newly selected transmission path is determined by the content control unit 13 by referring to the quality information table 18, and the information transmission unit 15 notifies the communication partner of the determined content quality information. As a result, data communication is performed using the newly selected content quality via the newly selected transmission path.

[0047] When the network interface management unit 26 detects that the state of the NIC 27 has changed, it registers the newly acquired information of the NIC 27 in the network interface information table 24 or deletes the registered information. , sends the updated NIC27 information to the communication partner. The communication terminal that receives this refers to the updated NIC27 information and its own network interface information table 24 to detect the transmission path that exists between the communication terminals.

[0048] When a transmission path is added, the status of each transmission path is updated for the newly extracted transmission path. (bottleneck bandwidth, RTT delay difference, etc.), register it in each transmission path information table 23, and select the transmission path again in the same way as when starting communication. In addition, when used for bidirectional communication, the priority of the transmission path is determined for each of the uplink and Z downlink, the highest priority transmission path is determined for each, and the determined transmission path is Data communication is carried out via the Internet. If a communication session has already been established via another transmission path, each transmission path is switched while maintaining that communication session.

[0049] FIG. 4 is an operation sequence diagram showing the operation of each part of the communication terminal 10 shown in FIG. 6 is a diagram showing an operation sequence when the data transfer quality of the transmission path in use changes. First, the operation sequence at the start of communication will be explained. In FIG. 4, the own terminal 29 is a communication terminal on the sending side that starts communication, and the communication partner terminal 30 is a communication terminal on the receiving side with respect to the communication terminal on the sending side. , is equipped with multiple network interfaces that can be connected to IP network 31. It is also assumed that data communications for video, audio, and other communications are being performed via the wireless access points and wireless base stations explained in Figures 1 and 2.

[0050] The connection may be one-to-one or may be a communication form such as a multipoint conference involving multiple people. Data communication may also be one-way server-client type communication or two-way communication such as a telephone. Further, in FIGS. 5 and 6, the own terminal 29 is the communication terminal that has detected a change in the communication state of the NIC, and the communication partner terminal 30 is the communication terminal with which the own terminal 29 is communicating. In this case, the own terminal 29 and the communication partner terminal 30 may be either the transmitting terminal or the receiving terminal. The same can be said about the form of communication as for the communication terminal in Figure 4. Further, each communication terminal may be a communication terminal in which one or both of them has one NIC and is not equipped with a single NIC.

[0051] First, Figure 4 (see Figure 3) shows the relationship between the own terminal 29 and the communication partner terminal 30 at the start of communication when the communication terminal performs data communication using an application that uses communication such as video and audio. The operation of each part will be explained. For example, if the transmission path management unit 20 is installed as middleware used in an ablation program, when the program is started, the network interface management unit 26 is installed in the own terminal 29. Obtain information about NIC attributes (for example, communication card name, transmission speed, radio field strength, link status, modulation method, MTU, etc.).

[0052] At the same time as acquiring this information, a communicable NIC is detected and registered in the network interface information table 24 (S401). After this registration, the network interface management unit 26 constantly monitors the communication status of the NIC, and if the status changes, writes the updated items in the network interface information table 24 each time. , the transmission path management unit 20 is notified only of the items that have changed. At this time, all items may be notified. Incidentally, FIG. 7 shows an example of the items registered in the network interface information table 24 described above and their values.

[0053] NIC detection methods include determination by comparing radio field strength with a threshold, link status, and the like. As an example of detection based on radio field strength, when the threshold is set to Level 3, if the radio field strength is Level 3 or higher, the flag is set to "1" (if the network interface is available, the flag is set to "1"). If it is not possible, set it to 0) and write it to the link status flag position of network interface information table 24.

[0054] On the other hand, if the radio field intensity is less than Level 3, the link status flag "0" is written in the same position as above. The threshold value may be determined by the application, may be built-in in the communication terminal in advance, or may be set by the user via the user setting section 12. According to the threshold values in this example, the network interface management unit 26 will not change the link status flag even if it detects that the wireless radio field intensity has changed from Level 1 to Level 2.

[0055] Further, as an example of detection based on link status, there are some NICs in mobile phones, PHS, etc. that cannot establish a connection to an IP network unless a dial-up connection is made. Therefore, if a dial-up connection is established, set the "ON" flag in the link status position of the network interface information table 2 to 4, and if a dial-up connection is established!, na!/, writes the “OFF” flag. Regarding the startup timing of the transmission path management unit 20, whether it is when the communication terminal 10 is started or when the application is started, it is sufficient that the transmission path management unit 20 is started before the application program starts communication. Even if the transmission line management unit 20 is included in the application program, the startup timing of the transmission line management unit 20 is the same as above. stomach.

[0056] Upon receiving a communication start request from the user setting unit 12, the application unit 11 notifies the own terminal 29 and the communication partner terminal 30 of information necessary for data communication in the application ( S414). Figure 8 (A) shows an example of the information items to be mutually notified at this time. Here, we determine the connection information necessary for sending and receiving data, such as the "connection destination IP address", standby "port number", and "session ID" necessary for communication session control, as well as the content information that can be used by the application. This includes ``video and audio encoding parameters (such as types of codecs that can be used)'' and ``transmission and reception protocols (RTP: Real-time Transport Protocol, UDP: User Datagram Protocol, etc.)'' to be used.

[0057] The above negotiation function may be realized using a signaling protocol for starting, managing, and terminating a session, such as SIP (Session Initiation Protocol) or RTSP (Real Time Streaming Protocol). Also, regarding the IP address, it may be an IPv4 (Internet Protocol Version 4) address or an IPv6 (Internet Protocol Version) address.

[0058] The application unit 11 creates a quality information table 18, which is a list of information on content that can be provided by the application, based on content information among the information acquired by the negotiation function. Figure 8 (B) shows the items of quality information table 18 and an example thereof. Note that the quality information table 18 may be set by the user from the user setting section 12.

[0059] Next, the application unit 11 notifies the transmission path management unit 20 of the information in the application priority criteria table 17 necessary for transmission path selection (S415, S416). Figure 8 (C) shows an example of the 17 items in the application priority criteria table. Each item in the application priority criteria table 17 is created from information written using the aforementioned negotiation function and items set by the user from the user setting section 12. Furthermore, regarding the application priority criteria table 17, all items may be set by the user from the user setting section 12, or may be set in the terminal in advance.

[0060] The transmission path management unit 20 stores the link status flag of the network interface information table 24. , and notifies the communication partner terminal 30 of the list of NICs with which it can communicate (S417). Figure 9 (A) shows an example of the items in the network interface list. The communication partner terminal 30 creates a list of transmission paths existing between its own terminal and the communication partner terminal based on the received network interface list and the network interface information table 24 in its own terminal.

[0061] For example, if the own terminal 29 has three usable NICs (NIC1 to 3) and the communication partner terminal 30 has two usable NICs (NIC4 to 5), the number of transmission paths is 3 ( The number of NICs on the own terminal) x 2 (the number of NICs on the communication partner terminal) x 2 (uplink transmission line and downlink transmission line) is 12. An example of the transmission path list in this example is shown in Figure 9 (B). The created transmission path list is notified from the communication partner terminal 30 to the own terminal 29, registered in each transmission path information table 23 (S404, S405), and then notified to each transmission path management unit 20. (S418, S419). The transmission path management unit 20 measures the transmission path state of each transmission path based on the notified information (S420).

[0062] Here, the items of the transmission path information table 23 are shown in FIG. Below are explanations of each item and examples of measurement methods. Figure 11 (A) shows an overview of the bottleneck physical bandwidth. Figure 11 (A) shows one of the transmission paths between the local terminal 29 and the communication partner terminal 30, where the width of the line represents the bandwidth, and the wider the line, the wider the bandwidth. The narrower the line, the narrower the bandwidth. In IP networks, there are various transmission paths along the route, so it is not possible to provide uniform bandwidth throughout the entire transmission path. Therefore, by measuring the bandwidth of the bottleneck of the transmission path and determining content quality based on the results, we can provide high-quality services at the maximum bit rate that allows data to be sent and received over the relevant transmission path. becomes possible.

[0063] As an example of a method for measuring the physical bandwidth of a bottleneck link, a measurement method using probe packets using a packet pair transfer method and a packet train transfer method will be described with reference to FIG. 11(B). If two packets of the same size S are sent closely together from the own terminal 29, and they are simultaneously queued on the bottleneck link, ΔΤ becomes SZB2. Since the packets arrive at the communication partner terminal 30 while maintaining the interval, ΔΤ^ =SZB2. B2 obtained from this equation becomes the bottleneck physical bandwidth in the transmission path.

[0064] Next, FIG. 12 shows an example of a method for measuring the RTT delay difference. In Figure 12, the own terminal 29 is equipped with three NICs, NIC1 to NIC3, and the communication partner terminal 30 is equipped with NIC4, and each is connected to an IP network. RTT can be measured by sending packets from the own terminal 29 to the communication partner terminal 30 and then to the own terminal 29, so the RTT of NIC1~NIC4~NIC1 is RTT1, ^1.1~^1.4~^[ . 1^11¾1^^2 of 2, NIC1 ~ NIC4 ~ NIC3 RTT RTT3, NIC1 → NIC4 one-way delay time ΔΤ, NIC4 → NIC 1 one-way delay time ΔΤ1, NIC4 → NIC2 one-way delay time If the delay time of is ΔΤ2, and the one-way delay time of NIC4 → NIC3 is ΔΤ3, then

ΔΤ1 = RTT1 - ΔΤ

ΔΤ2= RTT2- ΔΤ

ΔΤ3= RTT3- ΔΤ

becomes.

[0065] From the above formula, ΔΤ1, ΔΤ2, and ΔΤ3 are obtained by subtracting ΔΤ from RTT1, RTT2, and RTT3, respectively. Therefore, comparing RTT1, RTT2, and RTT3 means that from the communication partner terminal 29 This can be regarded as synonymous with comparing the relative delay difference in one direction to the own terminal 30. From the above, it is possible to use RTT1, RTT2, and RTT3 as one-way delay differences for NIC4 → NIC1, NIC4 → NIC2, and NIC4 → NIC3, respectively.

[0066] FIG. 13 is a diagram explaining the available bandwidth. Similar to FIG. 11 (A), it is one of the transmission paths between the own terminal 29 and the communication partner terminal 30, and the width of the line is the width of the bandwidth. The wider the line, the wider the bandwidth, and the narrower the line, the narrower the bandwidth. Also, the ``tsching'' part indicates that packets that have already been sent and received on that transmission path occupy the bandwidth of each link (cross traffic exists for each link). /, Ru.

[0067] In this case as well, the available bandwidth of the link on the transmission path between the transmitting and receiving terminals is measured by using the packet train method to transfer probe packets, similar to the measurement of the bottleneck physical bandwidth described above. can do. Here, we use the increasing tendency of the one-way transfer delay between each probe packet. Since the increasing tendency of the one-way transfer delay is observed when the transmission rate of probe packets exceeds the available bandwidth, we will explain this property. The available bandwidth can be increased by repeatedly measuring the probe packet transmission rate while changing the probe packet transmission rate. It becomes possible to ask for it. The packet loss rate can be determined by using the probe packets used in the above measurements: ``Packet loss rate = Number of packet losses (Number of packets that failed to receive) Z Number of transmitted packets.''

[0068] The above measurement is performed on the transmission path list (all transmission paths existing between the own terminal 29 and the communication partner terminal 30) registered in the transmission path information table 23. After the measurement is completed, the transmission path state management unit 25 writes the transmission path information obtained by the measurement method described above into the transmission path information table 23 (S406, S407). The transmission path selection unit 21 selects a transmission path from the acquired transmission path information table 23 and the application priority criteria table 17 (S408, S409) _o

[0069] FIGS. 14A and 14B are flowcharts showing an example of a processing procedure for selecting a transmission path suitable for an application request from the transmission path information table 23 and the application priority criteria table 17. First, as shown in Figure 14A, it is checked whether the priority NIC item is specified in the application priority criteria table 17 (S01). If a priority NIC is specified (S01YES), refer to the transmission path information in transmission path information table 23, check whether the specified priority NIC exists on the table and can be used (S02), and use it. If possible, select the priority NIC mentioned above (S02YES).

[0070] If the priority NIC item is not specified in the application priority criteria table 17 (S01NO), or if the priority NIC is not available (S02NO), the priority NIC item is not specified in the application priority criteria table 17. , check whether the item of charge priority is specified (S03). In this embodiment, it is assumed that either free, flat rate, or pay-as-you-go system is set as a fee setting item. If the free Z flat rate system is specified as the rate priority (S03YES), both the network interface information table 24 and the transmission path information table 23 are referred to to extract the free Z flat rate transmission path (S04).

[0071] Furthermore, if bandwidth priority is set in application priority criteria table 17,

(S05YES), the transmission path with the largest bandwidth is selected from the extracted transmission paths (S06). Then, if the bandwidth priority item is set (S05NO), check if the delay priority item is set, and if it is set (S07YES), the above extracted item will be checked. The transmission path with the smallest amount of delay is selected from among the transmission paths selected (S08). Sara Also, if the delay priority item is not set (S07NO), it is checked whether the extracted transmission path satisfies the required bandwidth and the required delay. If there is a transmission path that satisfies both conditions (S09YES, S10YES), the transmission path with the lowest fee and largest bandwidth is selected (S11).

[0072] If the extracted transmission path cannot satisfy either the required bandwidth or the required delay!/, (S 09NO, S10NO), move to the flow of Figure 14B and apply it to the transmission path with pay-as-you-go system. Then, a process similar to the process described above is performed to select a transmission path (S12 to S22). Also, even if charge priority is not set in the application priority criteria table 17 (S03NO), the same processing procedure is performed to select a transmission path (S12 to S22).

[0073] However, if neither bandwidth priority nor delay priority is set in application priority criteria table 17 (S12NO, S15NO), and there is no transmission path that satisfies the requested bandwidth (S19NO), the user The setting unit 12 is notified that there is no transmission path that satisfies the requested bandwidth (S21), and the user is notified that the service cannot be provided. In addition, even if the requested bandwidth is satisfied (S19YES), if the requested delay cannot be satisfied (S20NO), the user setting unit 12 is notified that there is no transmission path that satisfies the requested delay (S22), and the user We will notify you that we are unable to provide services to you. If the requested delay can be met (S20YES), return to the flow in Figure 14A and select the transmission path with the lowest fee and largest bandwidth (S11).

[0074] Since there are uplink and Z-downlink transmission paths, in this embodiment, each (own terminal and communication partner terminal) selects a downlink transmission path. In the case of server-client type one-way communication such as video streaming or audio streaming, the transmission path shall be selected on the client side. The present embodiment is not limited to this embodiment, and processing may be performed such that each terminal selects an upstream transmission path instead of a downlink transmission path, or one terminal selects either an upstream or Z-downward transmission path.

[0075] Here, an example in which different transmission paths are selected for uplink and Z-downlink will be explained using FIG. 15. The own terminal 29 is equipped with two NICs, FOMA and PHS, and the communication partner terminal 30 is equipped only with a wireless LAN (IEEE802.lib) NIC, and can be connected to the IP network via each NIC. Suppose that In this example, FOMA has a pay-as-you-go rate of 384kbps, The uplink rate will be 64kbps, the PHS will have a flat rate upstream and Z downlink rate of 64kbps, and the wireless LAN will have a flat rate rate of 11Mbps for upstream/downstream. In this case, the network interface information table 24 and transmission path information table 23 of each NIC are as shown in FIG. 16 (A) and FIG. 16 (B), respectively.

[0076] Furthermore, if the application priority criteria are set as NIC-free, bandwidth-prioritized, and pay-as-you-go, the application priority criteria table 17 will be as shown in FIG. 17. As shown in FIG. 16(B), in this embodiment, there are four transmission paths existing between the own terminal 29 and the communication partner terminal 30. When a transmission path is selected according to the transmission path selection flowchart described above (Figure 14A), the priority NIC is not specified for the transmission path from the own terminal 29 to the communication partner terminal 30 (S01NO), and the cost: Free Z flat rate system is not specified (S03NO), and the process moves to the flow shown in Figure 14B.

[0077] In the flow of Figure 14B, bandwidth priority is specified (S12YES), the bandwidths of transmission path 1 and transmission path 2 are the same, and there are transmission paths with the same band (S13YES), so the most "Transmission route 2" is selected as the transmission route with the lowest cost (S 17). Similarly, for the transmission path from the communication partner terminal 29 to the own terminal 30, the flow from Figure 14A to Figure 14B indicates that the priority NIC is not specified (S01NO) and the cost is free. It is not specified (S03NO), bandwidth priority is specified (S12YES), and the bandwidth of transmission path 3 is larger than that of transmission path 4!, so (S13NO), the bandwidth is the largest!/ , "Transmission path 3" is selected as the transmission path (S14).

[0078] Note that if bandwidth priority is not specified (S12NO) and delay priority is set (S1 5YES), and if a transmission path with the same delay exists (S16YES), the cheapest transmission will be used. path is selected (S17). If there is no transmission path with the same delay (S16NO), select the transmission path with the smallest amount of delay (S18).

[0079] As mentioned above, by selecting NICs with different upstream and Z-down transmission routes depending on the priority criteria of the application and the status of the transmission route, it is possible to use different transmission routes according to the preferences of the application and the user. becomes. In addition, the transmission path selection unit 21 does not select a single transmission path, but assigns a relative priority to each transmission path (each item is weighted, and based on the weighting, it assigns a relative priority to each transmission path). Calculate the points and choose the one with the highest points. It is also possible to set priority levels, notify the communication partner of the priority order, and let the communication partner decide on the transmission path.

[0080] Returning to FIGS. 3 and 4, when a transmission path is selected, the transmission path selection unit 21 refers to the transmission path information table 23 and notifies the application unit 11 of the transmission path information of the selected transmission path. (S421, S422). In this embodiment, the application unit 11 is notified of the bandwidth (bottleneck physical bandwidth) that can be allocated to the application as the transmission path state. Bandwidth is a major factor in determining the quality of application content.Depending on the target content, information such as transmission path delay, available bandwidth, and packet loss rate may be required. If necessary, please notify us of any of these information as well.

[0081] The content control unit 13 refers to the quality information table 18 based on the notified transmission path information and determines the content quality for communication (S412, S413). The communication control unit 14 starts transmitting and receiving data after exchanging with the communication partner information that determines the type of video and audio and usage parameters according to the content quality determined by the content control unit 13 as described above (S423). ), and at the same time, the IP control section 22 switches to the transmission path selected by the transmission path selection section 21 (S410, S411).

[0082] As described above, when the communication terminal 10 performs data communication using an application that uses communication such as video and audio through a wireless environment, the priority criteria of the application is determined based on the transmission path information between the communication terminals. By selecting the transmission path according to the user's preferences and preferences, it becomes possible to provide quality services that match the wireless environment and network information of the location where the communication terminal is located. Note that the transmission path is not limited to wireless, but may also be a medium that can be connected to an IP network, such as a wired LAN connection such as Ethernet (registered trademark).

[0083] Next, when the communication terminal 10 is performing data communication using an application using communication such as video or audio, the communication state of the transmission path surrounding the communication terminal changes. An example of the operation of each part of the communication partner terminal 30 will be explained with reference to FIG. 5 (see FIG. 3).

[0084] Users can take advantage of the advantages of wireless and move freely. Here, while traveling etc. For example, the network interface management unit 26 detects that the radio field strength of the previously unusable NIC (link status flag is "0") has increased and changed from Level 2 to Level 4, and sets the threshold value. If it is set to power evel3, the previously unusable network interface becomes usable. Notifies the transmission path management unit 20 that the NIC status has changed (S517), and writes the notified value to the corresponding location in the network interface information table 24 (rewrites the link status flag from ``0'' to ``1'') ) (S501).

[0085] The transmission path management unit 20 notifies the communication partner terminal 30 of information on the corresponding newly available network interface (S518). An example of the network interface information notified here is shown in Figure 18 (A). Here, in the case of the example at the start of communication (there are three usable NICs (NIC1 to 3) on the own terminal, two usable NICs (NIC4 to 5) on the communication partner terminal), and the own terminal 29 When NIC6 becomes available, send the added NIC name NIC6 and the corresponding IP address!/.

[0086] If there are multiple added network interfaces, a list of NIC names and corresponding IP addresses is sent. Here, the IP address may be an IPv4 address or an IPv6 address. Additionally, the list may be sent to all network interfaces that can communicate with each other, rather than just the added network interface. The communication partner terminal 30 creates a list of transmission paths added between its own terminal 29 and the communication partner terminal 30 based on the received network interface information and the network interface information table 24 in its own terminal.

[0087] If the transmitted network interface information is a list of all network interfaces with which communication is possible, a list of transmission paths existing between the own terminal 29 and the communication partner terminal 30 is created. An example of the list of added transmission paths is shown in Figure 18 (B). The list of created transmission paths is notified from the communication partner terminal 30 to its own terminal 29, registered in each transmission path information table 23 (S503, S504), and then notified to each transmission path management unit 20 (S519, S520).

[0088] The transmission path management unit 20 measures the transmission path state of the added transmission path based on the notified information (S521). The explanation and measurement method for each item will be the same as the method described in the example at the start of communication. The transmission path information and Based on the application priority criteria, the transmission route is determined according to the flowcharts in Figures 14A and 14B (S507, S508) _o If the determined transmission route is different from the transmission route currently in use (S509YES, S510YES), The transmission path selection unit 21 refers to the transmission path information table 23 and notifies the application unit 11 of the transmission path information of the selected transmission path (S522, S523).

[0089] In this embodiment, the application unit 11 is notified of the bandwidth that can be allocated to the application as the transmission path state, as in the embodiment at the time of starting communication. The content control unit 13 refers to the quality information table 18 based on the notified transmission path information and determines the content quality for communication. If it is determined that it is necessary to switch the content (S513YES, S514YES), the communication control unit 14 exchanges information with the communication partner to determine the type of video and audio and usage parameters according to the determined content quality. After that (S524), data transmission and reception starts with the switched content quality (S515, S516), and at the same time, the IP control unit 22 switches to the transmission path selected by the transmission path selection unit 21 (S511, S512).

[0090] Note that if the selected transmission path matches the transmission path currently in use, nothing is done. Additionally, if the selected transmission path is different from the transmission path currently in use and the content control unit 13 determines that there is no need to switch the content (S513NO, S51 4NO), only the transmission path is switched. (S511, S512).

[0091] In the above embodiment, an example of a change in the radio field strength was given, but when a dial-up connection of a mobile phone, PHS, etc. is established and changes from the ヽ na ヽ state to the established! ヽ state ( This may also be the case when the link status changes from "OFF" to "ON"), or when a new network interface is added and the link status of that network interface is "ON" or the link status flag is "1".

[0092] As described above, while the communication terminal 10 is performing data communication using an application that uses communication such as video and audio through the wireless environment, a new network interface is installed due to changes in the wireless environment. When the transmission path becomes available, the transmission path is reselected based on the transmission path information between the communication terminals, the priority criteria of the application, and the user's preferences, and the information based on the above transmission path is notified to the application. Provides quality service tailored to the wireless environment and network conditions of the location where the communication terminal is located. This makes it possible to provide services. Note that the transmission path may be not only wireless but also any medium that can be connected to an IP network, such as a wired LAN connection such as Ethernet (registered trademark).

[0093] Next, when the communication terminal 10 is performing data communication using an application using communication such as video or audio, the communication state of the transmission path surrounding the communication terminal changes. Another example of the operation of each part of the communication partner terminal 30 will be explained using FIG. 5 (see FIG. 3).

[0094] Users can take advantage of the advantages of wireless and move freely. For example, when you are moving, the wireless signal strength of the network interface that is currently communicating (link status flag "1") weakens, the level 4 power changes to level 2, and the threshold power is lowered. If it is set to Level 3, the previously usable network interface will become unusable. Notifies the transmission path management unit 20 that the network interface status has changed (S517), and writes the notified value to the corresponding location in the network interface information table 24 (changes the link status flag from ``1'' to ``0''). (Rewrite) (S 501).

[0095] The transmission path management unit 20 notifies the communication partner of the information (for example, the network interface name) of the corresponding unusable network interface (S518), and at the same time retrieves the corresponding information from the transmission path information table 23. Transmission path information is deleted (S503). Similarly, the communication partner terminal 30 also deletes the corresponding transmission path information from the transmission path information table 23 held by the communication partner terminal 30 based on the notified network interface information (S504).

[0096] The transmission path management unit 20 determines a transmission path based on the updated transmission path information and application priority criteria according to the flowcharts in FIGS. 14A and 14B (S507, S508). Here, the transmission path state management unit 25 again uses the updated transmission path information table 23 (for the transmission path after deleting the transmission path corresponding to the network interface whose state has changed). The transmission path state may also be measured (S519 to S521, S505, S506). When a new transmission path to be used is determined, the transmission path selection unit 21 refers to the transmission path information table 23 and notifies the application unit 11 of the transmission path information of the selected transmission path (S522, S5 twenty three).

[0097] In this embodiment, the application unit 11 is notified of the bandwidth that can be allocated to the application as the transmission path state, similar to the embodiment at the time of starting communication. The content control unit 13 refers to the quality information table 18 from the notified transmission path information to determine the content quality for communication, and if it is determined that content switching is necessary (S513YES, S514Y ES), After exchanging information determining the types of video and audio and usage parameters with the communication partner according to the content quality determined by the content control unit 13 (S524), data transmission and reception is started, and at the same time, the IP control unit 22 Switching is performed to the transmission path selected by the transmission path selection unit 21 (S511, S512). Furthermore, if the content control unit 13 determines that there is no need to switch the content (S513NO, S514NO), only the transmission path is switched (S511, S512).

[0098] In this example, the power described is the control when the radio field strength of the network interface currently in use weakens. Even if the network interface is weakened, information about the corresponding unusable network interface can be notified to the communication partner terminal 30!ヽ. The control procedure for deleting the information in the corresponding transmission path information table 23 at the own terminal 29 and the communication partner terminal 30 is the same, and the only difference is that in this case, no transmission path is selected. .

[0099] In the above embodiment, an example of a change in wireless radio field intensity was given, but when the state changes from an established dial-up connection of a mobile phone or PHS to an unestablished state (the link state changes to This may also be the case when the link status flag of a certain network interface changes from "1" to "0", or when the network interface is deleted (removed from the communication terminal).

[0100] As described above, while the communication terminal 10 is performing data communication using an application that utilizes communication such as video and audio through the wireless environment, a change in the state of the wireless environment triggers the current communication. Even if the status of the transmission path in use changes, the transmission path can be reselected based on the transmission path information between communication terminals, application priority standards, and user preferences. Notify the application of information based on the above transmission path This makes it possible to provide quality services that match the wireless environment and network conditions of the location where the communication terminal 10 is located. Note that the transmission path may be not only wireless but also any medium that can be connected to an IP network, such as a wired LAN connection such as Ethernet (registered trademark).

[0101] Next, when the communication terminal 10 is performing data communication using an application using communication such as video and audio, the communication state of the transmission path surrounding the communication terminal changes. Another example of the operation of each part of the communication partner terminal 30 will be explained using the same FIG. 5 (see FIG. 3).

[0102] Users can take advantage of the advantages of wireless and move freely. For example, changes in the physical link speed of the wireless communication of the network interface currently in use (changes in physical transmission speed in IEEE802.1 LB from 11Mbps to 5.5Mbps, etc.) , a change in the bearer transmission speed in FOMA (from 384kbps to 64kbps, etc.) is detected. The transmission path management unit 20 is notified of the change in the NIC status (S517), and the value notified in the corresponding section of the network interface information table 24 (transmission speed is 11Mbps or 5.5Mbps!/, ίma, 384kbps power, 64kb ps, etc.) (S501).

[0103] The transmission path management unit 20 notifies the communication partner terminal 30 of information on the network interface whose communication state has changed (S518). Here, an example of the network interface information to be notified is shown in Figure 18 (C). Here, in the case of the example at the start of communication, NIC1 is the network interface of EEE802. l ib, and the transmission speed of NIC1 of the own terminal 29 has changed from 11Mbps to 5.5Mbps. Only the updated information is sent (S518). If there are multiple network interfaces whose communication status has changed, a list of the NIC names and the information in the updated portion of the network interface information table 24 corresponding to them is sent. Also, feel free to send us a list of all network interfaces that can communicate, not just the updated part!/ヽ

[0104] The communication partner terminal 30 updates the network interface information table 24 in its own terminal based on the received network interface information, and the transmission path management unit 20 The transmission line state of the corresponding transmission line is measured (S521). Here, we decided to re-measure only the transmission line status of the transmission line corresponding to the updated network interface, but it is also possible to re-measure the transmission line status of all transmission lines. Regarding the explanation of each item and the measurement method, the same method as described in the example at the start of communication will be used. Based on the transmission path information and application priority criteria thus obtained, a transmission path is determined according to the flowcharts in FIGS. 14A and 14B (S507, S508).

[0105] If the determined transmission path is different from the transmission path currently in use (S509YES, S51 OYES), the transmission path selection unit 21 refers to the transmission path information table 23 and selects the selected transmission path. The transmission path information is notified to the application unit 11 (S522, S523). In this embodiment, as in the embodiment at the start of communication, the application unit 11 is notified of the bandwidth that can be allocated to the application as the transmission path state.

[0106] Content control unit 13 refers to quality information table 18 based on the notified transmission path information and determines the content quality for communication. If it is determined that it is necessary to switch the content (S513YES, S514YES), the communication control unit 14 communicates with the communication partner information that determines the type of video and audio and usage parameters according to the determined content quality. After the exchange (S524), data transmission and reception starts with the switched content quality (S51 5, S516) ₀ At the same time, the IP control unit 22 switches to the transmission route selected by the transmission route selection unit 21. (S511, S512) _0Nothing is done if the selected transmission path matches the transmission path currently in use. In addition, if the selected transmission path is different from the transmission path currently in use and the content control unit 13 determines that there is no need to switch the content, then only the transmission path can be switched (S513NO, S514NO). Do (S511, S512).

[0107] In this example, the case where the physical link speed of wireless communication of the network interface changes has been described, but when it is detected that the wireless modulation method has been changed (modulation method in I EEE802. Even when the method is changed from QPSK to BPSK), it is possible to provide quality services that match the communication environment by performing control according to the processing procedure described in this example.

[0108] Next, when the communication terminal is performing data communication using an application that uses communication such as video or audio, the data transfer item is specified on the application program. An example of the operation of each part of the own terminal 29 and the communication partner terminal 30 when the quality changes will be explained using FIG. 6 (see FIG. 3).

[0109] When starting communication, as described above, a transmission path is selected according to the priority criteria of the available transmission path and the application program, and data communication is started with content quality that is suitable for the transmission path. After starting data communication, the transfer quality measurement unit 16 in the application unit 11 constantly monitors the transfer quality. The acquired data transfer quality is compared with the transmission path quality table 28, and if a change in the state of the transfer quality is detected, a transmission path switching request (S601) is notified to the transmission path management unit 20.

[0110] Here, an example of the transmission path quality table 28 is shown in FIG. 19(A). Regarding each item in the transmission path quality table 28, the effective bandwidth of the transmission path, the amount of delay of transferred data (RTT), and the packet rate are Next, the values of each item in the transmission path information table 23 corresponding to the transmission path with the highest priority are registered. In this embodiment, it is assumed that the number of retransmitted packets is set in advance by the service provider. Note that this value may be set by the user from the user setting section 12.

[0111] Below, explanations of each item and examples of measurement methods in the transfer quality measurement section 16 are given. First, regarding bandwidth, the effective bandwidth is obtained from the data size of packets received during a certain period of time. The transfer quality measurement unit 16 can distinguish between the first packet and the last packet received at any fixed time based on the packet sequence number, so it can calculate the data size of the packet received between time T1 and time T2. Assuming S, the effective bandwidth BW can be calculated from the following formula.

BW=S X 8 X 1024/ (T2—T1)

As for the packet loss rate, as a result of controlling the retransmission of data packets on the receiving terminal side, by checking the above sequence number of the transferred data on the receiving terminal side, the packet loss rate = The number of packet losses can be calculated from Z number of packets sent.

[0112] Similarly, data retransmission control can be performed by checking the above sequence number. In this embodiment, retransmission control defined by ARQ (Automatic Repeat Request) is used as the retransmission control method. Figure 20 explains retransmission control This is a diagram. The receiving terminal side (communication partner terminal 30) checks the sequence number assigned to each data packet during data communication, and if discontinuity in the above sequence numbers of the transferred data is detected, the transmitting terminal side ( It sends a retransmission request for the relevant packet to its own terminal29) and calculates the number of retransmitted packets. If packet loss occurs continuously, specify multiple packets in one retransmission request.

[0113] Furthermore, since the total of the retransmission request transmission time and the retransmission packet reception time is approximately equal to the RTT, the retransmission request interval is set to a value greater than the RTT delay difference. From the above, the number of times a retransmission request can be sent is determined by the RTT delay difference and the jitter buffer, and in an environment with little network delay jitter, the number of possible retransmissions = jitter buffer ÷ RTT. Since the size of the jitter noffer varies depending on the capability of the receiving terminal, in this embodiment, the amount of change in the number of retransmitted packets is used as a comparison item for the quality of the transmission path.

[0114] Next, the one-way delay amount will be described below based on FIG. 21. The one-way delay amount is obtained for each data packet during data communication when the transmission time on the sending terminal side is "Tk" and the receiving time on the receiving terminal side is "Tk'". It is determined by "one-way delay amount = reception time Tk' - transmission time Tk". However, since it is difficult to synchronize the time between the own terminal (sending terminal side) and the communicating party terminal (receiving terminal side) within an error of several tens of milliseconds, in this example, the reception time at the communicating party terminal 30 and the packet The relative one-way delay amount is calculated by considering the minimum value of the transmission timestamp history (minimum one-way delay amount) as delay 0. In Figure 21, if the transmission path from local terminal 29 to communication partner terminal 30 is currently using NIC1 to NIC4, detect the change in relative one-sided delay from End to End from NIC1 to NIC4. I can do it.

[0115] The above changes in data transfer quality are detected based on values measured using data during data communication, and items such as bandwidth, RTT, and packet loss rate are periodically transmitted. Comparison is made with the values registered in the road quality table 28. The communication control unit 14 detects that the state of data transfer quality has changed when it falls below a registered value, that is, exceeds a threshold value. Regarding the one-way delay amount and the number of retransmitted packets, if each value exceeds a certain percentage, it is detected that the data transfer quality has changed. [0116] When a change in the data transfer quality of the transmission path is detected as described above, the transmission path management unit 20 is notified of a transmission path switching request (S601). The transmission path management unit 20 writes the transfer quality deterioration flag corresponding to the transmission path number assigned to the transmission path currently in use in the transmission path information table 23 (S602), and sends the flag to the communication partner terminal 30. A transmission path switching request (S604) is notified. An example of a transmission path switching request is shown in Figure 19 (B). Similarly, on the communication partner terminal side, the transmission path management unit 20 writes into the transmission path information table 23 the transfer quality deterioration flag corresponding to the transmission path number assigned to the notified transmission path currently in use.

[0117] Here, if the measurement request of the transmission path switching request is not set (S603NO), the content control unit 13 refers to the transmission path quality table 28 and determines the content quality. If it is determined that it is necessary to switch the content (S615YES), the information transmission unit 15 exchanges with the communication partner information that determines the type of video and audio and usage parameters according to the determined content quality. Later (S616, S617), data transmission and reception starts with the switched content quality (S618), and at the same time, the IP control unit 22 switches to the next candidate transmission path in response to the transmission path switching request (S620, S621).

Note that if the content control unit 13 determines that there is no need to switch the content (S615NO), only the transmission path is switched.

[0118] If the measurement request flag of the transmission path switching request is set (S603YES), the transmission path management unit 20 determines the transmission path condition for the target transmission path from the communication partner terminal to the local terminal. Measure the status (S606, S608). Regarding the explanation and measurement method of each item, the same method as described in the example at the start of communication will be used. At this time, there is no need to perform measurements for transmission path numbers whose transfer quality degradation flags are set to ON. Based on the transmission path information and application priority criteria obtained in this way, a transmission path is determined according to the flowcharts shown in Figures 14A and 14B (S611, S612). The transmission path selection unit 21 refers to the transmission path information table 23 and notifies the application unit 11 of the transmission path information of the selected transmission path (S613).

[0119] In this embodiment, the application unit 11 is notified of the bandwidth that can be allocated to the application as the transmission path state, as in the embodiment at the time of starting communication. The communication control unit 14 compares the notified transmission path information with the value measured by the transfer quality measurement unit 16. Cut the transmission line If it is determined that it is necessary to change the content (S614YES), the content control unit 13 determines the content quality by referring to the quality information table 18 based on the notified transmission path information.

[0120] Here, if it is determined that it is necessary to switch the content (S615YES), the information transmission unit 15 transmits information that determines the type of video and audio and usage parameters according to the determined content quality to the communication partner. (S618), data transmission and reception starts with the switched content quality, and at the same time, the communication control unit 14 sends a transmission path switching notification to the transmission path management unit 20 to switch to the selected transmission path. Notification (S619), and the IP control unit 22 switches to the notified transmission path (S620, S621).

[0121] Furthermore, as a result of comparing the notified transmission path information with the value measured by the transfer quality measurement unit 16, if it is determined that there is no need to switch the transmission path (S614NO), nothing is done. If the above result determines that it is necessary to switch the transmission path (S614YES), and if the content control unit 13 determines that there is no need to switch the content (S615NO), only the transmission path is switched (S620, S621) ). However, the transmission path may be set not to be switched at the user's request.

[0122] Next, when the communication terminal is performing data communication using an application that uses communication such as video and audio, if the data transfer quality changes on the application program, the decision to switch the transmission path is made. Another example of the operation of each part of the own terminal 29 and the communication partner terminal 30 when prompting the user will be explained using FIG. 6 (see FIG. 3) and FIG. 22.

[0123] As described above, at the time of starting communication, a transmission path is selected according to the priority criteria of the available transmission path power application program, and data communication is started with content quality suitable for the transmission path. After starting data communication, the transfer quality measurement unit 16 in the application unit 11 constantly monitors the data transfer quality. Regarding the detection of a change in data transfer quality, the means of the embodiment described above is used, and when a change is detected, data transfer quality information is displayed on the screen via the user setting section 12.

[0124] FIG. 22 is an example of a screen that displays data transfer quality information and prompts the user to switch transmission paths. When the user presses the transmission path switching button, a transmission path request is sent to the transmission path management section 20. is notified, and the transmission path switching process is performed as in the above embodiment. The transmission path to be switched to is presented to the user as the transmission path with the next highest priority after the transmission path currently in use from among the previously determined priorities. Here, the transmission path with the highest priority may be determined and selected based on the results of reacquiring transmission path information for available transmission paths other than the transmission path currently in use. Note that nothing is done if the user presses the cancel button.

In addition, in this embodiment, the same control is performed when the communication state changes at the communication partner terminal 30, and the transmission path is changed. It will be possible to link selection and applications and provide quality services that match the user's communication status.

Claims

The scope of the claims

[1] A communication terminal equipped with a network interface that can connect to multiple transmission paths is a wireless communication system that uses multiple transmission paths,

means for detecting a communicable network interface among the plurality of network interfaces;

means for acquiring network interface information regarding predetermined attributes of the plurality of network interfaces;

means for creating a list of transmission paths existing between the communicable network interface and the communicable network interface of the communication partner;

means for acquiring information regarding the state of a transmission path corresponding to the transmission path list; and means for determining a transmission path by determining the priority of the transmission path based on either the network interface information or the transmission path information. Equipped with

What is claimed is: 1. A wireless communication system comprising: means for detecting a change in the state of data transfer quality of a transmission path in use after starting data communication; and means for detecting the change in state and switching the transmission path.

[2] The wireless communication system according to claim 1, wherein the means for detecting a change in the state of data transfer quality is provided in an application program.

[3] The wireless communication system according to claim 2, further comprising means for causing the user to determine switching of the transmission path after detecting the change in the state of the data transfer quality.

[4] The state change of the data transfer quality is determined by comparing the data transfer quality obtained from data during data communication with the transmission path information of the transmission path selected according to the determined priority of the transmission path as a threshold value. The wireless communication system according to any one of claims 1 to 3, characterized in that the detection is performed by:

[5] Claim 1, wherein the change in the state of the data transfer quality is detected by comparing the data transfer quality obtained from data during data communication with a preset threshold.

The wireless communication system according to any one of Items 1 to 3.

[6] The wireless communication system according to claim 4 or 5, wherein the transmission path selected as the switching destination is a transmission path with the next highest priority after the transmission path currently in use.

[7] The transmission path selected as the switching destination is determined as the transmission path with the highest priority after reacquiring the transmission path information from among the available transmission paths other than the transmission path currently in use. 6. The wireless communication system according to claim 4 or 5, characterized in that:

[8] The data transfer quality to be compared is the one-way delay amount,

For each data packet during data communication, if the sending time on the sending terminal side is Tk and the receiving time on the receiving terminal side is obtained as T, then

"One-way delay amount = Reception time Tk' Transmission time Tk"

8. The relative one-way delay amount is calculated by determining the one-way delay amount based on the one-way delay amount and considering the minimum value of the one-way delay amount as zero delay. The wireless communication system described in .

[9] The data transfer quality to be compared is the number of retransmitted packets, and the receiving terminal checks the sequence number assigned to each data packet during data communication to determine whether the transferred data The method according to any one of claims 4 to 7, characterized in that when a discontinuity in the packet is detected, a retransmission request for the corresponding packet is transmitted to the transmitting terminal side, and the number of retransmitted packets is calculated. Wireless communication system.

[10] The data transfer quality to be compared is the packet loss rate, and by controlling the retransmission of data packets on the receiving terminal side and checking the sequence number of the packet received at the receiving terminal,

"Packet loss rate = Number of packet losses Z Number of packets sent"

8. The wireless communication system according to claim 4, wherein the wireless communication system calculates a packet loss rate.

[11] The data transfer quality to be compared is the effective bandwidth of the transmission path, and is characterized in that it is calculated from the size of data received in a certain period of time with respect to data during data communication received at the receiving terminal side. The wireless communication system according to any one of claims 4 to 7.

[12] The wireless communication system according to claim 3 or 4, wherein the network interface information includes communication status detected in a layer lower than a transport layer.

[13] The network interface information includes the network interface transmission speed. 13. The wireless communication system according to claim 12, characterized in that:

[14] The wireless communication system according to claim 13, wherein if the network interface transmission speed is different for uplink and Z-downlink, each is acquired as separate information.

[15] The transmission path information according to claim 3 or 4, wherein the transmission path information includes a bottleneck physical bandwidth between a network to which the plurality of network interfaces are connected and a communication partner. Wireless communication system.

[16] The wireless communication system according to claim 3 or 4, wherein the transmission path information includes available bandwidth between a network to which the plurality of network interfaces are connected and a communication partner. .

[17] According to claim 3 or 4, the transmission path information includes an RTT (Round Trip Time) delay difference between a transmission path to which the plurality of network interfaces are connected and a communication partner. The wireless communication system described.

18. The wireless communication system according to claim 3, wherein the transmission path information includes a communication cost between a transmission path to which the plurality of network interfaces are connected and a communication partner.

19. The wireless communication system according to claim 3, wherein the priority of the transmission path is determined based on priority criteria set for each application program that performs data communication.

[20] The wireless communication system according to claim 19, characterized in that in the case of an asymmetric communication network in which uplink and Z-downlink transmission path characteristics are different, different transmission paths can be selected for uplink and Z-downlink based on the priority criteria.

[21] The wireless communication system according to claim 19, wherein when the requested bandwidth is used as a priority criterion, a plurality of the requested bandwidths are set for each application program.

[22] A means for detecting a change in the state of a network interface that is not in data communication after starting data communication;

means for acquiring network interface information regarding predetermined attributes of the plurality of network interfaces; Again, means for creating a list of transmission paths existing between the communicable network interface and the communicable network interface of the communication partner;

means for acquiring transmission path information regarding the state of the transmission path corresponding to the newly created transmission path list;

means for determining the priority of the transmission path, including the transmission path in progress, based on either the network interface information or information related to the transmission path information, and determining the transmission path;

22. The wireless communication system according to claim 1, wherein when the determined transmission path is different from the transmission path in progress, switching to the newly determined transmission path is performed. .

[23] By monitoring the transmission path status of the transmission path being used and comparing it with an arbitrary threshold, the priority of the transmission path is re-judged, and the transmission path with the highest priority is determined. 23. The wireless communication system according to claim 22, characterized in that:

[24] The wireless communication according to claim 22, wherein a change in the wireless modulation method is detected, the priority of the transmission path is determined again, and the transmission path with the highest priority is determined. system.

[25] A wireless communication method in which a communication terminal equipped with a network interface connectable to multiple transmission paths uses multiple transmission paths,

detecting a communicable network interface among the plurality of network interfaces;

obtaining network interface information regarding predetermined attributes of the plurality of network interfaces;

creating a list of transmission paths existing between the communicable network interface and the communicable network interface of the communication partner;

obtaining information regarding the state of the transmission path corresponding to the transmission path list;

determining the priority of the transmission path based on either the network interface information or the transmission path information, determining the transmission path and starting data communication;

After starting data communication, it detects changes in the data transfer quality of the transmission path in use and transmits the data. A wireless communication method characterized by switching transmission routes.

After starting data communication, it detects a change in the status of a network interface that is not currently communicating,

Again, create a list of transmission paths that exist between the communicable network interface and the communicable network interface of the communication partner,

Obtaining transmission path information regarding the status of the transmission path corresponding to the newly created transmission path list,

determining the priority of the transmission path including the transmission path in progress based on either the network interface information or the information regarding the transmission path information, determining the transmission path, and determining the transmission path so that the determined transmission path is the communication path. 26. The wireless communication method according to claim 25, characterized in that if the selected transmission path is different from the currently determined transmission path, switching to the newly determined transmission path is performed.