JP2008219656A - Edge router device for mobile wireless communication for handover, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an edge router device for mobile wireless communication and a program in which a rate can be speedily adapted to a terminal subjected to handover when a terminal receiving a series of real-time data performs handover. <P>SOLUTION: An edge router device transfers a data packet received from a transmission source device via a core network, to a terminal via a wireless communication network. When communication status information transmitted from the terminal is received, the transmission source device controls a transmission rate of the data packet in accordance with the communication status information. The edge router device includes a feedback information generating means for transmitting, to the transmission source device, communication status information of a wireless communication network after handover with the handover of terminals between different wireless communication networks. The communication status information is based on a format of feedback information specified by a transport layer protocol for real-time applications. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an edge router apparatus and program for mobile radio communication for handover.

  There is a handover technique in which a terminal communicates while switching a wireless communication network to be connected according to the movement. Examples of wireless communication networks include cellular and PHS (Personal Handyphone System) networks such as CDMA2000 1x, CDMA2000 1x EVDO, and W-CDMA, wireless LAN (Local Area Network) networks (IEEE802.11, etc.), wireless MAN (Metropolitan Area). Network) (IEEE802.16 etc.). In order to realize handover between different wireless communication networks, the terminal needs to have different wireless communication functions in advance.

  FIG. 1 is a configuration diagram of a mobile communication system in the prior art.

  According to FIG. 1, a content server 6 having various contents such as video data is connected to a core network 1 based on IP (Internet Protocol). In addition, a plurality of different wireless communication networks 21, 22, and 23 are connected to the core network 1. According to FIG. 1, the wireless communication network 21 is a CDMA2000 1x EVDO network, the wireless communication network 22 is a wireless LAN network, and the wireless communication network 23 is a wireless MAN network. The communication speed is assumed to decrease in the order of the wireless LAN network 22> the wireless MAN network 23> the EVDO network 21.

  Each wireless communication network 21, 22, and 23 is provided with edge router devices 31, 32, and 33 for mobile wireless communication. Further, one of the edge router devices 31, 32 and 33 is connected to the core network 1, and the other is connected to the base stations 41, 42 and 43.

  A terminal 5 for mobile radio communication can be connected to the core network 1 by connecting to one of the base stations 41, 42 or 43. Since the base station 41, 42, or 43 is based on different communication functions, the terminal 5 needs to include a plurality of different wireless communication function units.

  However, even if the terminal includes a plurality of different wireless communication function units, normally, communication with the wireless communication network before handover cannot be continued with communication with the wireless communication network after handover. This is because the IP address assigned to the terminal changes due to the handover. For this reason, a technology capable of continuing communication before handover has been developed.

  For example, according to MobileIP (see, for example, Non-Patent Document 1), a terminal has two IP addresses, an IP address that does not change and an IP address that changes every handover. An IP packet transmitted to an invariant IP address is encapsulated and transferred to an IP address that changes every handover by a home agent device installed in the network. Thereby, the communication before the handover is continued after the handover.

  In addition, according to a technique for managing movement using SIP (Session Initiation Protocol) (see, for example, Non-Patent Document 2) (SIP Mobility), after a handover, a communicating party terminal can perform handover from a terminal that has performed handover. The later IP address and the session identifier before the handover are notified. Thereby, the communication before the handover is continued after the handover.

  According to FIG. 1, using these techniques, the terminal 5 can execute a handover from the content server 6 while continuing to receive a download of a file or a streaming of a video.

  On the other hand, representative transport layer protocols include TCP (Transport Control Protocol) and UDP (User Datagram Protocol). TCP is mainly used for data-related applications that can tolerate a certain amount of delay. Also, UDP is mainly used for real-time applications that have strict delay times.

  TCP has a rate control function according to the congestion state of the network. However, UDP continues to send packets at a constant rate without providing such a rate control function. Therefore, in the case of UDP, there is a risk of congestion collapse on the network.

  Thus, there is DCCP (Datagram Congestion Control Protocol) as a transport layer protocol technology for real-time applications (see Non-Patent Document 7, for example). DCCP uses a technique called TRFC (TCP-Friendly Rate Control) (see Non-Patent Document 3, for example).

  TRFC achieves fairness with TCP traffic through control compatible with the congestion control function of TCP even when using UDP. The TRFC defines feedback information (information indicating a network state such as a reception transmission rate, a loss event rate, and a round trip delay time) transmitted from the receiving device to the transmitting device. The transmitting apparatus that has received the feedback information gently controls fluctuations in the packet transmission rate so as to be suitable for real-time multimedia transmission. In order to control the gradual rate fluctuation, the feedback information has a longer transmission interval than TCP (every received packet), for example, every round-trip delay time.

  FIG. 2 is a packet format diagram of DCCP.

  FIG. 2 shows a DCCP generic packet format and a DCCP-ACK packet format. In addition, for example, a reception transmission rate option field, a loss event rate option field, and a time stamp option field are added to perform TFRC congestion control.

  FIG. 3 is a sequence diagram showing feedback information when the TFRC technique in the prior art is used.

  According to FIG. 3, the terminal 5 transmits feedback information to the content server 6 that is a transmission source device for each round-trip delay time, for example, when receiving streaming video. The content server 6 that has received this feedback information adjusts the transmission rate.

  Here, according to FIG. 1, it is assumed that the terminal 5 is connected to the wireless LAN network 22 and receives a series of real-time data from the content server 6. At this time, the terminal 5 is about to be handed over to the EVDO network 21 by the movement. Below, the aspect which hands over from the wireless LAN network 22 to the EVDO network 21 is demonstrated concretely. However, the present invention is not limited to this mode of handover, and can be applied to a case where handover is performed to the same wireless communication network or a case where handover is performed to another different wireless communication network.

  According to the above-described technologies such as MobileIP and SIP mobility, communication in the wireless LAN network 22 is continued even when connected to the EVDO network 21. However, the communication speed of the EVDO network 21 is extremely lower than the communication speed of the wireless LAN network 22. For this reason, traffic data with a high transmission rate for the wireless LAN network 22 flows into the EVDO network 21. Such traffic data causes an abrupt congestion state in the EVDO network 21 and affects the communication of other terminals 5 connected to the EVDO network 21 from the beginning. According to FIG. 3, after connection to the EVDO network, traffic data with a high transmission rate in the wireless LAN flows into the EVDO network for a while.

  Therefore, when the terminal 5 is receiving the download of the file from the content server 6 using TCP, the edge router device 31 or the base station 41 provided in the EVDO network 21 has a certain period of time immediately after the handover of the terminal 5. However, there is a technique for buffering packets addressed to the terminal 5 (see, for example, Non-Patent Documents 4 and 5). This technique can reduce the influence on other terminals 5.

  On the other hand, when the terminal 5 is streaming video from the content server 6 using UDP, there is a technique in which the edge router device 31 provided in the EVDO network 21 converts, for example, a compression method or a screen size (for example, Patent Document 1). With this technology, it is possible to prevent a large amount of traffic from flowing into the EVDO network 21.

  Also, there is a technique in which the terminal 5 detects a communication state in the EVDO network 21 for a certain time after the handover and transmits the communication state information to the content server 6 for real-time traffic using TRFC (for example, non-patent). Reference 6). With this technique, rate control according to the EVDO network 21 can be performed.

C. Perkins, Ed .: “IP Mobility Support,” RFC2002, Oct.1996. E. Wedlund and H. Schulzrinne, “Mobility Support using SIP,” WoWMoM '99, Aug. 1999. M.Handley, S.Floyd, J.Pahdye and J.Widmer: “TCP Friendly Rate Control (TFRC): Protocol Specification”, RFC 3448, Proposed Standard, Jan. 2003. Y. Matsushita, T. Matsuda, M. Yamamoto: "Graceful Degradation of Transport Layer in Mobile Internet", WWIC2004, Feb. 2004. Izumikawa, Matsunaka, Sugiyama, "Handover considering already connected terminals in heterogeneous wireless network environment," IEICE, B-7-77, Sep.2006 A. Gurtov and J. KorMNen, “Effect of Vertical Handovers on Performance of TCP-Friendly RateControl,” ACM Mobile Computing and Communications Review, 8 (3): 73-87, Jul. 2004. E. Kohler, M. Handley and S. Floyd, “Datagram Congestion Control Protocol (DCCP),” RFC4340, IETF, Mar. 2006. JP 2004-248202 A

  The technology for buffering packets addressed to the terminal 5 by the edge router device 31 or the base station 41 includes a mechanism for controlling the packet transmission amount in accordance with the available bandwidth of the actual network within a short time. It is what you use. In addition, it is an effective technology because it targets non-real-time applications such as file download that do not cause frequent fluctuations in the transmission rate and delay time.

  If this technology is applied to real-time traffic using TFRC such as video streaming reception, packets addressed to the terminal 5 are buffered by the edge router 31 or the base station 41 even temporarily. For this reason, the transmission rate and delay jitter vary greatly, and packet discard occurs. As a result, the quality of the real-time traffic is greatly deteriorated, for example, the video is greatly disturbed.

  In addition, as described above, in TFRC, the packet transmission rate is controlled so as to moderate in accordance with the characteristics of real-time multimedia transmission such as video streaming reception. Furthermore, especially the delay time in the radio link of the CDMA2000 1x EVDO network 21 is much larger than the delay time of the wired link. That is, the round trip delay time between the content server 6 and the terminal 5 may be considerably larger than the round trip delay time between the content server 6 and the base station 41. Therefore, according to the technique of Non-Patent Document 6, in addition to the time for the terminal 5 to detect the communication state in the EVDO network 21, it takes time for the transmission rate to change to one suitable for the EVDO network 21. The influence of communication on the terminal 5 connected to the EVDO network is large.

  Further, according to Patent Document 1, the edge router device 31 can also be controlled to convert, for example, a compression method and a screen size into real-time traffic addressed to the terminal 5. Thereby, the influence of the communication with respect to the terminal connected to the EVDO network 21 from the beginning can be reduced. However, as long as the terminal 5 is connected to the EVDO network 21, the edge router 31 has a problem that the processing load on the edge router 31 is high because the edge router 31 controls the compression method and the screen size conversion.

  Therefore, the present invention reduces the influence on other terminals connected in advance to the wireless communication network after the handover when a terminal receiving a series of real-time data performs a handover, and allows the terminal to perform a handover. An object of the present invention is to provide an edge router apparatus and program for mobile radio communication capable of quickly adapting the rate.

According to the present invention, there is provided an edge router device that transfers a data packet received from a transmission source device via a core network to a terminal via a wireless communication network, wherein the transmission source device is a communication state transmitted from the terminal. When receiving information, an edge router apparatus in a system that controls the transmission rate of data packets according to the communication state information,
It is characterized by having feedback information generating means for transmitting the communication state information of the wireless communication network after the handover to the transmission source device with the handover of the terminal.

  According to another embodiment of the edge router device of the present invention, the communication status information is preferably a transmission rate, a loss event rate, and / or a round trip delay time.

  According to another embodiment of the edge router apparatus of the present invention, the communication state information is preferably based on a format of feedback information defined by a transport layer protocol for a real-time application.

  According to another embodiment of the edge router apparatus of the present invention, the handover is preferably between different wireless communication networks.

According to another embodiment of the edge router device of the present invention,
Buffer means for buffering packets addressed to the terminal after the handover;
The buffer means preferably discards the packet based on a discard rate calculated from a transmission rate of traffic addressed to the terminal and an available transmission rate of the wireless communication network after the handover.

  According to another embodiment of the edge router apparatus of the present invention, it is also preferable that the feedback information generating means always transmits the communication state information of the wireless communication network to the transmission source apparatus.

According to the present invention, there is provided an edge router device that transfers a data packet received from a transmission source device via a core network to a terminal via a wireless communication network, wherein the transmission source device is a communication state transmitted from the terminal. A program for causing a computer mounted on an edge router device in a system to control a data packet transmission rate according to the communication state information when receiving information,
Along with the handover of the terminal, the computer is caused to function as feedback information generating means for transmitting the communication state information of the wireless communication network after the handover to the transmission source device.

  According to another embodiment of the edge router apparatus of the present invention, it is also preferable to cause the computer to function so that the communication status information is a transmission rate, a loss event rate, and / or a round trip delay time.

  According to another embodiment of the edge router apparatus of the present invention, it is also preferable to make the computer function so that the communication state information is based on a format of feedback information defined by a transport layer protocol for a real-time application. .

  According to another embodiment of the edge router apparatus of the present invention, it is also preferable to make the computer function when the handover is between different wireless communication networks.

According to another embodiment of the edge router device of the present invention,
Buffer means for buffering packets addressed to the terminal after the handover;
The buffer means preferably causes the computer to function so as to discard the packet based on a discard rate calculated from a transmission rate of traffic addressed to the terminal and an available transmission rate of the wireless communication network after the handover.

  According to another embodiment of the edge router apparatus of the present invention, it is also preferable that the feedback information generating means causes the computer to always function to transmit the communication state information of the wireless communication network to the transmission source apparatus.

  According to the edge router apparatus and program for mobile radio communication of the present invention, when a terminal receiving a series of real-time data such as video streaming reception performs a handover for switching a radio communication network, the radio after the handover is performed. It is possible to reduce the influence on other terminals connected in advance to the communication network and to quickly adapt the rate to the terminal that performs handover.

  Specifically, the edge router device after the handover transmits feedback information to the transmission source device in place of the terminal after the handover. The feedback information includes communication state information. Thereby, the transmission source device can adjust the data transmission rate.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 4 is a first system configuration diagram according to the present invention.

  According to FIG. 4, it is assumed that the terminal 5 receives a series of real-time data from the content server 6 via the wireless LAN network 22. For example, video streaming reception. It is assumed that the terminal 5 is handed over from the wireless LAN network 22 to the EVDO network 21 by the movement during the reception.

  According to FIG. 4, the edge router apparatus 3 includes a base station direction interface unit 301, a core network direction interface unit 302, a feedback information generation unit 303, an address registration unit 304, a communication quality measurement unit 305, a traffic monitoring Part 306. These functional units can also be realized by executing a program that causes a computer mounted on the edge router device to function.

  The base station direction interface unit 301 is a communication interface connected to the base station 4 and communicates with the terminal 5. The core network direction interface unit 302 is a communication interface connected to the core network 1 and communicates with the content server 6.

  The feedback information generation unit 303 creates communication state information of the wireless communication network, that is, communication state information of the EVDO network 21 according to the edge router device 31, instead of the terminal 5. The communication state information may be feedback information (reception transmission rate, loss event rate, round trip delay time) based on TRFC.

  The address registration unit 304 registers the source address and the destination address in the packet addressed to the handed over terminal.

  The communication quality measuring unit 305 measures communication state information of the base station direction interface unit 301, that is, the wireless communication network 2. The measured communication state information is notified to the feedback information generation unit 303. The items of communication state information to be measured may be items of feedback information (reception transmission rate, loss event rate, round trip delay time) based on TRFC. The round-trip delay time information may be a round-trip delay time between the edge router device 3 and the terminal 5.

  The traffic monitoring unit 306 monitors traffic in the core network direction interface unit 302.

  After handing over from the wireless LAN network 22 to the EVDO network 21, the terminal 5 performs mobility registration using, for example, MobileIP, SIP mobility technology, or DHCP (Dynamic Host Configuration Protocol). Simultaneously with this movement registration, the terminal 5 transmits the address information (IP address and port number) of the content server 6 to the edge router device 31 via the base station 41. The edge router device 31 stores the received address information in the address registration unit 304. The movement registration request is transmitted to a home agent (not shown), the content server 6 or a router (not shown), and the movement registration is completed. Then, the packet addressed to the terminal 5 transmitted from the content server 6 is transferred to the EVDO network 21.

(S201) The edge router 31 receives a packet addressed to the terminal 5 from the core network direction interface unit 302. Then, it is determined whether or not the address of the packet is registered in the address registration unit 304, that is, whether or not the terminal at the address is a terminal that has been handed over.

  When the destination address of the packet is not the terminal that has performed handover, the packet is notified to the base station direction interface unit 301. Thereby, the packet is transmitted to the terminal 5 via the base station 41.

(S202) On the other hand, when the destination address of the packet is the terminal that has handed over, the feedback information creation unit 303 of the edge router device 31 returns the feedback information based on the communication state information measured by the communication quality measurement unit 305. Is generated. The feedback information is transmitted from the core network direction interface unit 302 to the content server 6. At this time, the address information of the packet is recorded in the address registration unit 304.

  The communication state information is an available communication speed, a loss event rate, and time information (delay time). For these pieces of information, the communication state information measured by the communication quality measuring unit 305 in the edge router device 3 may be used as it is.

  The time information (delay time) is obtained by subtracting the round-trip delay time between the edge router device 3 registered in the communication quality measurement unit 305 and the terminal 5 from the time stamp value described in the packet addressed to the terminal 5 It may be.

  Also, considering the relationship with other traffic, for example, a communication speed lower than the available communication speed registered in the communication quality measurement unit 305 or a delay time larger than the delay time registered in the communication quality measurement unit 305 May be used.

  Furthermore, it is also preferable that the feedback information is transmitted every predetermined number of packets or every predetermined time (round). This round may be based on TRFC.

(S203) Thereafter, the packet is transmitted from the base station direction interface unit 301 to the terminal 5 via the base station 41.

  Next, the traffic monitoring unit 306 of the edge router device 31 has a rate at which the traffic of a series of packets having a destination address destined for the terminal 5 matches the communication state information included in the feedback information transmitted to the content server 6. Or whether it is close to a certain level. When the traffic of a series of packets transmitted from the content server 6 to the terminal 5 reaches a rate suitable for the communication state information or approaches a certain level, the address registration unit 304 displays an address related to the terminal 5 and the content server 6. Delete information.

(S204) On the other hand, the edge router device 31 receives the communication state information from the terminal 5 to the content server 6 by the base station direction interface unit 301. At this time, the address registration unit 304 searches for information related to the terminal 5 and the content server 6. If registered, the address information is deleted. If not registered, the packet is transferred to the core network direction interface unit 302. As a result, the packet is transmitted to the content server 6 via the core network 1.

  The feedback information transmitted from the terminal 5 to the edge router device 31 after handover from the wireless LAN network 22 to the EVDO network 21 includes received packets in the wireless LAN network 22 in addition to the IP address and port number of the content server 6. Information (sequence number, time stamp, etc.) may be included. Such information is recorded in the address registration unit 304.

  FIG. 5 is a sequence diagram showing the first feedback information in the present invention.

  According to FIG. 5, when the edge router device 31 detects the handover of the terminal 5 and then forwards the packet addressed to the terminal 5 from the content server 6 to the terminal 5, the edge router device 31 returns the feedback information of the EVDO network 31 to the content server 6. Send to. The content server 6 that has received this feedback information adjusts the transmission rate. Compared to FIG. 3, according to FIG. 5 of the present invention, the content server 6 receives the feedback information immediately without waiting for one round-trip delay time, so that the transmission rate is adjusted quickly.

  According to FIG. 4, the edge router device 3 may include a buffer unit 307 that buffers only a specific packet. The buffer unit 307 buffers only packets of address information registered in the address registration unit 304, which are packets addressed to the terminal 5 from the content server 6. According to FIG. 4, it is represented by a broken line.

  The address information of the packet received by the core network direction interface unit 302 is recorded in the address registration unit 304 and notified to the buffer unit 307. The buffer unit 307 calculates a packet discard rate from the traffic transmission rate obtained from the traffic monitoring unit 306 and the available transmission rate obtained from the communication quality measuring unit 305. Then, the buffer unit 307 discards the buffered packet at the discard rate. The packet that is not discarded is notified to the base station direction interface unit 301 and transmitted to the terminal 5 via the base station 4.

  Further, when calculating the discard rate, the available queue rate in the interface queue that buffers all packets may be used instead of the available transmission rate obtained from the communication quality measuring unit 305. Furthermore, instead of the transmission rate obtained from the traffic monitoring unit 306, the amount of packets destined for the terminal 5 staying in the core network 1 may be used.

  Further, when the terminal 5 is handed over, a packet addressed to the terminal 5 is bicast by the server device (not shown) toward the EVDO network 21 and the wireless LAN network 22, or from the edge router device 32 to the edge router device. In the case where the packet is transferred to 31, it is also preferable to discard the received packet in the buffer 307 from the received packet information recorded in the address registration unit 304.

  FIG. 6 is a second system configuration diagram according to the present invention.

  According to FIG. 6, the edge router device 3 further includes a feedback information storage unit 308 and a communication quality storage unit 309. These functional units can also be realized by executing a program for causing a computer mounted on the edge router device to function. According to FIG. 6, the communication quality information server 7 is connected to the core network 1. The communication quality information server 7 stores communication quality information of a plurality of wireless communication networks 2.

  The feedback information storage unit 308 stores the feedback information received from the terminal 5 and rewrites it as necessary. The communication quality storage unit 309 receives the communication quality information of the wireless communication apparatus 2 from the communication quality information server 7 and stores it.

  The terminal 5 predicts whether or not to hand over to another wireless communication network 2 from lower layer (for example, physical layer) information (for example, degradation of reception level) when connected to the wireless LAN network 22. Is possible. At this time, the terminal 5 transmits a handover notification for handing over to the edge router device 32. At this time, the address information of the terminal 5 is recorded in the address registration unit 304.

  The handover notification includes information for specifying the edge router device 31 that is the handover destination. If the handover notification does not include information for specifying the edge router device as the handover destination, information for specifying the edge router device 31 may be acquired from another server device.

  When receiving the handover notification, the edge router device 32 acquires the communication quality information of the EVDO network 21 from the communication quality information server 7 and records it in the communication quality storage unit 309.

  At the same time, it waits for feedback information transmitted from the terminal 5. When receiving the feedback information from the terminal 5, the edge router 32 records it in the feedback information storage unit 308. Then, the information in the communication quality storage unit 309 is used to rewrite the feedback information suitable for the communication state in the EVDO network 21. The rewritten feedback information is transferred to the content server 6. The terminal 5 recorded in the address registration unit 304 is deleted when a predetermined time has elapsed or when a handover completion notification is received from the terminal 5.

  FIG. 7 is a sequence diagram showing the second feedback information in the present invention.

  According to FIG. 7, the edge router device 31 transmits the feedback information of the EVDO network 31 to the content server 6 when receiving the handover notification of the terminal 5. The content server 6 that has received this feedback information adjusts the transmission rate. Compared to FIG. 5, according to FIG. 7 of the present invention, the content server 6 receives feedback information before the handover, so that the transmission rate is adjusted quickly.

  Here, when the communication status information (delay time, available communication speed, packet loss rate, etc.) in each wireless communication network 2 is known from the base station 4 (41, 42, 43) to the terminal 5, the terminal 5 The communication state information may be included in the handover notification to the edge router device 3 by the above. In this case, the information is recorded in the communication quality storage unit 309.

  Further, the edge router device 32 transmits a handover notification of the terminal 5 to the edge router device 31 to the edge router device 32, and the edge router device 31 that has received the handover notification from the edge router device 32 has its own communication quality. Feedback information may be transmitted to the content server 6 using the communication state information of the measurement unit 305.

  The edge router device 32 uses the information in the communication quality storage unit 309 and the information in the communication quality measurement unit 305 so that the transmission rate of the handover destination wireless communication network 2 is higher than the transmission rate of the wireless communication network 22. When it is determined that the value is high, it is also preferable to add a process that does not rewrite the feedback information suitable for the communication state in the handover destination wireless communication network 2. At this time, feedback information may be rewritten to increase the rate up to an available transmission rate in the wireless communication network 22 using information of the communication quality measuring unit 305 instead of information that matches the communication state in the handover destination wireless communication network 2. .

  As a further embodiment, the edge router device 3 may always transmit feedback information to a transmission source device that is a communication partner of the terminal 5 regardless of whether or not the terminal 5 is handed over. In order to realize this, the address registration unit 304 stores address information of all terminals 5 connected to the edge router device 3. Further, every time the feedback information transmitted from the terminal 5 is transmitted to the transmission source device that is the communication partner of the terminal 5, the feedback information storage unit 308 stores the feedback information.

  As described above in detail, according to the edge router apparatus and program for mobile radio communication of the present invention, a terminal receiving a series of real-time data such as video streaming reception switches the radio communication network. When performing a handover, it is possible to reduce the influence on other terminals connected in advance to the wireless communication network after the handover, and to quickly adapt the rate to the terminal that performs the handover.

  Specifically, the edge router device after the handover transmits feedback information to the transmission source device in place of the terminal after the handover. The feedback information includes communication state information. Thereby, the transmission source device can adjust the data transmission rate.

  According to the present invention, since the rate can be controlled in a short time without being affected by a radio link having a large delay time at the time of handover of the terminal, the load on the network and the terminal other than the terminal to be handed over can be controlled. The influence on communication can be reduced.

  Further, the edge router device only transmits the feedback information to the transmission source device, and does not require a new control packet, and can transmit radio resources effectively without transmitting duplicate unnecessary packets.

  Furthermore, since the transmission rate can be set in advance in accordance with the handover destination network, the load on the network due to the handover and the influence on the communication of terminals other than the terminal to be handed over can be minimized.

  According to the various embodiments of the present invention described above, those skilled in the art can easily make various changes, modifications and omissions within the scope of the technical idea and the viewpoint of the present invention. The above description is merely an example, and is not intended to be restrictive. The invention is limited only as defined in the following claims and the equivalents thereto.

It is a block diagram of the mobile communication system in a prior art. It is a packet format diagram of DCCP. It is a sequence diagram showing the feedback information at the time of using the TFRC technique in a prior art. It is a 1st system block diagram in this invention. It is a sequence diagram showing the 1st feedback information in the present invention. It is a 2nd system block diagram in this invention. It is a sequence diagram showing the 2nd feedback information in the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Core network 2 Wireless communication network 21 CDMA2000 1x EVDO network 22 Wireless LAN network 23 Wireless MAN network 3 Edge router apparatus 31 Edge router apparatus of EVDO network 32 Edge router apparatus of wireless LAN network 33 Edge router apparatus of wireless MAN network 301 Base station Direction interface unit 302 Core network direction interface unit 303 Feedback information generation unit 304 Address registration unit 305 Communication quality measurement unit 306 Traffic monitoring unit 307 Buffer unit 308 Feedback information storage unit 309 Communication quality storage unit 41 EVDO network base station 42 Wireless LAN network Base station 43 Wireless MAN network base station 5 Terminal 6 Content server 7 Communication quality information server

Claims (12)

An edge router device that transfers data packets received from a transmission source device via a core network to a terminal via a wireless communication network, wherein the transmission source device receives communication state information transmitted from the terminal An edge router apparatus in a system that controls the transmission rate of data packets according to the communication state information,
An edge router apparatus comprising feedback information generation means for transmitting the communication state information of the wireless communication network after the handover to the transmission source apparatus with the handover of the terminal.   The edge router apparatus according to claim 1, wherein the communication state information is a transmission rate, a loss event rate, and / or a round trip delay time.   The edge router apparatus according to claim 1, wherein the communication state information is based on a format of feedback information defined by a transport layer protocol for a real-time application.   The edge router according to any one of claims 1 to 3, wherein the handover is between different wireless communication networks. Buffer means for buffering packets addressed to the terminal after the handover;
2. The buffer means discards the packet based on a discard rate calculated from a transmission rate of traffic destined for the terminal and an available transmission rate of a wireless communication network after handover. 5. The edge router device according to any one of items 1 to 4.   The edge router device according to any one of claims 1 to 5, wherein the feedback information generation unit always transmits communication state information of a wireless communication network to the transmission source device. An edge router device that transfers data packets received from a transmission source device via a core network to a terminal via a wireless communication network, wherein the transmission source device receives communication state information transmitted from the terminal At the time, a program for causing a computer mounted on an edge router device in a system to control the transmission rate of data packets according to the communication state information,
A program for an edge router apparatus, characterized by causing a computer to function as feedback information generation means for transmitting the communication state information of a wireless communication network after handover to the transmission source apparatus with handover of the terminal.   8. The program for an edge router device according to claim 7, wherein the communication state information causes a computer to function so as to be a transmission rate, a loss event rate, and / or a round trip delay time.   9. The edge router apparatus according to claim 7, wherein the communication state information causes the computer to function so as to be based on a format of feedback information defined by a transport layer protocol for a real-time application. Program.   The program for an edge router according to any one of claims 7 to 9, wherein a computer is caused to function when the handover is between different wireless communication networks. Buffer means for buffering packets addressed to the terminal after the handover;
The buffer means causes the computer to function to discard the packet based on a discard rate calculated from a transmission rate of traffic addressed to the terminal and an available transmission rate of the wireless communication network after handover. The program for an edge router device according to any one of claims 7 to 10, characterized in that:   The edge router according to any one of claims 7 to 11, wherein the feedback information generation unit causes a computer to always transmit communication state information of a wireless communication network to the transmission source device. A program for a device.

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