WO2014087765A1

WO2014087765A1 - Terminal and communication system

Info

Publication number: WO2014087765A1
Application number: PCT/JP2013/079331
Authority: WO
Inventors: 一範小澤
Original assignee: 日本電気株式会社
Priority date: 2012-12-03
Filing date: 2013-10-23
Publication date: 2014-06-12

Abstract

In order to prevent any deterioration in quality of experience (QoE), this terminal, which is connected to a network and receives requested content from a content server via said network, is provided with the following: a packet reception unit that receives from the content server, via the network, packets constituting a content file or content stream corresponding to the requested content; a congestion detection unit that detects network congestion on the basis of the received packets; and a packet transmission control unit that, if network congestion has been detected, uses the reverse direction of the network to send the content server a request to change the file size of the content or a request to change the rate of the content.

Description

Terminal and communication system

The present invention relates to a terminal such as a portable terminal connected to a network, and more particularly to a terminal used for a communication system that performs congestion control of video / audio / audio communication and content distribution data by a packet.

In recent years, the capacity and speed of mobile networks have been increased, and systems such as LTE (Long Term Evolution) and EPC (Evolved Packet Core) have begun to be introduced.
In conventional communication systems, circuit switching for voice calls and videophone calls and packet switching for sending data are configured as separate systems. On the other hand, in the LTE / EPC system, voice call data, videophone data, content distribution data, and so-called data signals (application data, document data, photo data, etc.) flow together on the same packet communication path. Features. Furthermore, as mobile terminals, the spread of so-called smart devices such as smartphones and tablets as well as conventional so-called Galapagos mobiles is accelerating.
Thereby, in the LTE / EPC system, a packet with a huge amount of data that cannot be compared with the conventional communication system flows through the packet communication path.
Therefore, in the LTE / EPC system, it is necessary to perform packet transfer rate control. For example, Japanese Patent Laying-Open No. 2004-320452 (Patent Document 1) discloses a packet transfer control device that performs packet transfer rate control.
The packet transfer control device disclosed in Patent Document 1 includes a line congestion state determination unit, a transfer rate control determination unit, and a packet processing unit. The line congestion state determination unit determines whether the backbone line is congested based on the accumulated packet total amount that is the accumulated value of the packet size for a plurality of packets. When determining that the backbone line is in a congested state, the transfer rate control determination unit selects one or more IP (Internet Protocol) flows having a hop count value lower than the threshold value. The packet processing unit determines whether the IP flow selected by the transfer rate control determination unit is a TCP (Transmission Control Protocol) packet. In the case of a TCP packet, the packet processing unit performs the following three types of packet processing. Apply.
Specifically, 1) In the case of an outgoing packet from the server, the CE (Consultation Experience) bit of ECN (Explicit Connection Notification) is set in the TCP header. 2) In the case of a reply packet returned from the client, the advertisement window size of the TCP header is reduced and changed. 3) In the case of an acknowledgment (Ack) packet, the transmission timing of the packet to the backbone line is delayed. If it is not a TCP packet, the packet is discarded.

JP 2004-320452 A ([0051] to [0057])

Until now, in packet transfer control devices (for example, EPC P-GW: Packet data network Gateway or S-GW: Serving Gateway), QCI (Quality Class Id) is used as a parameter for controlling QoS (Quality of Service). Parameters such as (Maximum Bit Rate) and GBR (Guaranteed Bit Rate) are set, and QoS is controlled for each packet.
However, since the network bandwidth of the entire LTE / EPC system varies temporally depending on the temporal variation of the traffic volume, QCI (Quality Class Identifier), MBR (Maximum Bit Rate), GBR (Guaranteed Bit Rate) Transfer control by setting parameter values such as (Rate) is not sufficient, and in the worst case, there is a risk of problems related to quality of experience (QoE) degradation, such as the screen being frozen on the terminal or the sound being interrupted. It was.
Note that Patent Document 1 merely discloses a packet transfer control device that selects one or more IP flows having a hop count value lower than a threshold value when the backbone line is congested. That is, Patent Document 1 does not recognize the above-described problem relating to the deterioration of QoE, and does not disclose any specific configuration of a terminal such as a mobile terminal.
An object of the present invention is to provide a terminal capable of avoiding QoE degradation.

A first aspect of the present invention is a terminal connected to a network and receiving requested content from a content server via the network, and a content file or a content stream corresponding to the requested content is transmitted from the content server via the network. A packet reception unit that receives the packet as a packet, a congestion detection unit that detects network congestion based on the packet received by the packet reception unit, and a network server that detects congestion of the network when the congestion detection unit detects network congestion. And a packet transmission control unit for notifying a request to change the file size of the content using the reverse direction of the network.
A second aspect of the present invention is a terminal that is connected to a network and receives requested content from a content server via the network. A content file or a content stream corresponding to the requested content is transmitted from the content server via the network. A packet receiving unit that receives the packet, a congestion detection unit that detects network congestion based on the packet received by the packet receiving unit, and a network server that detects congestion of the network when the congestion detection unit detects network congestion. A packet transmission control unit for notifying a request for changing the content rate by using a reverse direction of the network.

According to the present invention, it is possible to avoid a congestion state even when the traffic changes significantly compared to the statistical value.

FIG. 1 is a block diagram showing a connection configuration of a communication system to which the present invention is applied.
FIG. 2 is a block diagram showing the configuration of the mobile terminal according to the first embodiment of the present invention used in the communication system shown in FIG.
FIG. 3 is a block diagram showing a configuration of a mobile terminal according to the second embodiment of the present invention used in the communication system shown in FIG.

Hereinafter, embodiments and operations of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a communication system to which the present invention is applied. Here, a configuration in which the mobile LTE / EPC packet network 150 is used as the network is shown.
Further, in the communication system of FIG. 1, a packet transfer control device 190 (to be described later) shows a configuration using P-GW (Packet data network Gateway) or S-GW (Serving Gateway) or both. The mobile terminal is assumed to be a so-called Galapagos mobile phone, a smartphone, or a tablet.
In the communication system of FIG. 1, an example is shown in which a user requests content from the content server 145 of the Internet network 140, and the content server 145 distributes the requested content to the mobile terminal 170 via the mobile network 150. Yes.
In the communication system of FIG. 1, as an example of congestion detection, a configuration in which the mobile terminal 170 detects congestion by receiving congestion information by ECN (Explicit Connection Notification) for downlink packets received from the mobile network 150 is shown. . Here, when the outdoor LTE radio base station apparatus (eNodeB apparatus) 194 detects a congestion state in the wireless network, the ECN of the IP (Internet protocol) header portion of the downlink packet that the eNodeB apparatus 194 sends to the mobile terminal 170 It is assumed that the mobile terminal 170 is in a congested state by setting a CE (Congestion Experience) bit in the field.
In the communication system of FIG. 1, when the mobile terminal 170 sends, for example, a content server URL (uniform resource locator) and a content server IP (internet protocol) address to the content server 145 as a content request, the request message is The eNodeB device 194 and the packet transfer control device 190 are transferred to the content server 145 on the Internet 140. Here, as an example, the HTTP (hyper transfer protocol) / TCP (transmission control protocol) protocol is used for the request message.
The PCRF device 191 inputs the IP address and port number of the mobile terminal 170 from the packet transfer control device 190 in at least one of the upstream and downstream directions. If necessary, the PCRF device 191 also inputs parameters such as a desired QoS class, MBR (Maximum Bit Rate), GBR (Guaranteed Bit Rate), etc. from the packet transfer control device 190 as QoS information.
Next, the PCRF device 191 generates a QoS parameter for QoS control. The QoS parameter for QoS control is at least one of QCI (Quality Class Identifier) which is a value for identifying a QoS class, ARP (Allocation and Retention Priority) indicating the priority of resource reservation and retention, MBR, and GBR. is there. Here, the MBR and the GBR are used as they are when received from the packet transfer control device 190, and are generated by the PCRF device 191 when there is no reception.
The PCRF device 191 generates at least one of these four types of QoS parameters for each of the uplink direction and the downlink direction, and sends them to the packet transfer control device 190. For the mobile terminal 170, since the traffic is content delivery, the values of the downstream QoS parameters are set, for example, as QCI = 6 (TCP-based www), ARP = 6, GBR = 512 kbps, MBR = 1 Mbps. To do.
The packet transfer control device 190 inputs at least one of four types of QoS parameters, QCI, ARP, MBR, and GBR, for each traffic data from the PCRF device 191. That is, the packet transfer control device 190 receives at least one of four types of QoS parameters for the content distribution traffic in the downlink direction from the RCRF device 191 and performs packet transfer control according to the set value of the QoS parameters.
[First Embodiment]
Next, the configuration of the mobile terminal 170 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 2 is a block diagram illustrating a configuration of the mobile terminal 170.
As illustrated in FIG. 2, the mobile terminal 170 includes a packet receiving unit 250, a packet transmitting unit 251, a video / audio / audio decoder 253, a rate setting unit 254, and a congestion detection unit 255.
In FIG. 2, the packet receiving unit 250 first receives a downlink packet transmitted from the eNodeB apparatus 194 in FIG. Then, the packet receiving unit 250 extracts information on the IP header portion and payload data from the received packet. The packet receiving unit 250 sends information in the IP header part to the congestion detection unit 255 and sends payload data to the video / audio / audio decoder 253. Here, it is assumed that an RTP / UDP (user datagram protocol) / IP packet is used as the protocol of the received packet.
The congestion detection unit 255 inputs the information of the IP header portion of the downstream packet, and checks the ECN (Explicit Connection Notification) field of the IP header portion. When the CE bit is set in the ECN field, the congestion detection unit 255 indicates that the downlink network from the eNodeB device 194 to the portable terminal 170 or the downlink network from the packet transfer control device 190 to the portable terminal 170 is congested. It detects that there is, and sends down congestion detection information to the rate setting unit 254.
When the congestion detection information in the downlink direction is input from the congestion detection unit 255, the rate setting unit 254 changes the setting of the requested content rate. For example, when content with a bit rate of 1 Mbps at the maximum is requested before the congestion, the rate setting unit 254 changes the bit rate to 512 kbps at the maximum after the congestion, and sets the changed rate (bit rate). The packet is transmitted to the packet transmission unit 251.
The video / audio / audio decoder 253 inputs payload data from the packet receiving unit 250, operates the video / audio / audio decoder, and inputs a video / audio / audio compression-encoded bitstream included in the payload data. These are decoded, the video obtained by decoding is displayed, and the reproduced audio signal is output.
The packet transmitting unit 251 receives the changed rate value from the rate setting unit 254, sets the packet in the reverse direction, that is, in the upstream direction, and then transmits the packet. Here, when HTTP is used as the protocol, if the content server 145 accepts a bit rate message or a bandwidth message, specify the changed bit rate as “bit rate =” in the HTTP message, or , “Bandwidth =” can be used to specify the changed bit rate.
When the content server 145 has a plurality of files with different bit rates for the same title, a file name having a desired file size can be specified in the HTTP message. The packet in which these are written in the HTTP message reaches the content server 145 of FIG. 1 via the eNodeB device 194 and the packet transfer control device 190 as an upstream network.
As described above, the combination of the rate setting unit 254 and the packet transmission unit 251 makes a request to the content server 145 to change the content file size or a request to change the content rate when the congestion of the network 150 is detected. It functions as a packet transmission control unit that notifies using the reverse direction of the network 150.
The content server 145 in FIG. 1 identifies the bit rate, bandwidth, or file name in the HTTP message sent from the mobile terminal 170, reads the content at the changed rate, and distributes the content to the mobile terminal 170.
Although the description of the configuration of the first embodiment of the present invention has been completed above, various modifications are possible.
In the first embodiment, an HTTP message is used as a request to change the rate to the content server 145. However, as another configuration, an RTCP (RTP Control Protocol) packet or an RTCP-APP (APPLICATION SPECIFIC) packet is used. The rate change value and file name can also be written in these. Furthermore, SIP (Session Initiation Protocol) / SDP (Session Description Protocol) or RTSP (Real Time Streaming Protocol) / SDP can be used as a request to change the rate to the content server 145. In the case of using SDP, for example, the changed rate can be included in the parameter “b =”.
In the first embodiment, congestion detection uses ECN information, but other information can also be used.
The mobile network 150 may be a 3G network, and the packet transfer control device 190 may be an SGSN (Serving GPRS Support Node) or a GGSN (Gateway GPRS Support Node).
In addition, an IP network such as NGN (Next Generation Network) can be used instead of the 3G network. Further, instead of the eNodeB device 194, a W-LAN (Wireless Local Area Network) access point may be used.
The portable terminal 170 can be realized by a program executed by a computer. That is, the mobile terminal 170 may be configured by a packet transmission / reception control processor (not shown) and a storage device (not shown). The storage device stores a packet transmission / reception control program. In this case, the packet transmission / reception control processor performs the above-described packet transmission / reception control operation according to the packet transmission / reception control program stored in the storage device.
Next, effects of the first exemplary embodiment of the present invention will be described.
According to the first embodiment of the present invention, when network congestion is detected at a terminal, a request to change the file size of the requested content or a request to change the content rate is sent to the content server. It is possible to notify using the direction. As a result, it is possible to avoid a congestion state, and there is an effect that it is possible to avoid deterioration of QoE (Quality of Experience) such as the sound being interrupted and the screen being frozen at the terminal. Furthermore, even if services such as high sound quality VoIP and high resolution TV phone are started using the packet communication path of the LTE / EPC system in the future, there is an effect that deterioration of QoE on the terminal side can be avoided.
[Second Embodiment]
Next, the configuration of a mobile terminal 170A according to the second embodiment of the present invention will be described with reference to FIG.
FIG. 3 shows a configuration in which portable terminal 170A estimates a network bandwidth and calculates a rate to be changed based on the estimated value when congestion is detected. In FIG. 3, the constituent elements having the same numbers as those in FIG. 2 perform the same operations as in FIG.
The mobile terminal 170A has the same configuration as the mobile terminal 170 shown in FIG. 2 except that a band estimation unit 257 is added and the operation of the rate setting unit is changed as will be described later. Therefore, the reference numeral 258 is attached to the rate setting unit.
When the output signal from the congestion detection unit 255 indicates that the downstream network congestion has been detected, the bandwidth estimation unit 257 is the nth immediately after the congestion detection in the packet reception unit 250 according to the following equation (1). For a packet received after the time, the delay time T (n) of the packet is measured.
T (n) = R (n) −S (n) (1)
Here, T (n), R (n), and S (n) indicate the delay time of the nth packet, the reception time of the nth packet, and the transmission time of the nth packet, respectively. .
Further, the bandwidth estimation unit 257 measures delay values for a plurality of subsequent consecutive packets, smooths them in the time direction, and then obtains the bandwidth W of the downstream network from the following equation (2). Is estimated.
W = D / ST (2)
Here, W is the estimated bandwidth of the network, D is the time smoothed value of the received data size, and ST is the time smoothed value of the delay time.
Then, the band estimation unit 257 outputs the estimated band W to the rate setting unit 258.
When the downlink congestion detection information is input from the congestion detection unit 255, the rate setting unit 258 sets the changed rate in order to change the content rate. Here, it is assumed that the content server 145 supports a plurality of different bit rate files for the same content. In such a case, specifically, the rate setting unit 254 receives the bandwidth estimation value W of the downstream network from the bandwidth estimation unit 257, and from the plurality of rates supported by the requested content, A rate satisfying equation (3) is selected and set to the changed rate.
B (i) <W (3)
Here, B (i) is the i-th rate among the N types of rates supported by the requested content, and 1 <i <N. Here, N is the number of bit rates supported by the requested content, and is set to 5, for example.
Here, when there are two types of bit rates satisfying Expression (3), 256 kbps and 512 kbps, the rate setting unit 254 selects a higher bit rate. Therefore, here, the rate setting unit 258 selects 512 kbps and sends it to the packet transmission unit 251.
Therefore, the combination of the bandwidth estimation unit 257, the rate setting unit 258, and the packet transmission unit 251 changes the request for changing the file size of the content to the content server 145 or the content rate when the congestion of the network 150 is detected. It functions as a packet transmission control unit that notifies a request to be made using the reverse direction of the network 150.
This is the end of the description of the configuration of the second exemplary embodiment of the present invention, but various modifications are possible.
In the second embodiment, the HTTP message is used as a request to change the rate to the content server 145. However, as another configuration, an RTCP (RTP Control Protocol) packet or an RTCP-APP (APPLICATION SPECIFIC) is used. Using a packet, a rate change value and a file name can be written in these. Furthermore, SIP (Session Initiation Protocol) / SDP (Session Description Protocol) or RTSP (Real Time Streaming Protocol) / SDP can be used as a request to change the rate to the content server 145. In the case of using SDP, for example, the changed rate can be included in the parameter “b =”.
In the second embodiment, ECN information is used to detect congestion, but other information can also be used.
The mobile network 150 may be a 3G network, and the packet transfer control device 190 may be an SGSN (Serving GPRS Support Node) or a GGSN (Gateway GPRS Support Node).
In addition, an IP network such as NGN (Next Generation Network) can be used instead of the 3G network. Further, instead of the eNodeB device 194, a W-LAN (Wireless Local Area Network) access point may be used.
The portable terminal 170A can be realized by a program executed by a computer. That is, the mobile terminal 170A may be composed of a packet transmission / reception control processor (not shown) and a storage device (not shown). The storage device stores a packet transmission / reception control program. In this case, the packet transmission / reception control processor performs the above-described packet transmission / reception control operation according to the packet transmission / reception control program stored in the storage device.
Next, effects of the second exemplary embodiment of the present invention will be described.
According to the second embodiment of the present invention, when network congestion is detected at a terminal, a request to change the file size of the requested content or a request to change the content rate is sent to the content server. It is possible to notify using the direction. As a result, it is possible to avoid a congestion state, and there is an effect that it is possible to avoid deterioration of QoE (Quality of Experience) such as the sound being interrupted and the screen being frozen at the terminal. Furthermore, even if services such as high sound quality VoIP and high resolution TV phone are started using the packet communication path of the LTE / EPC system in the future, there is an effect that deterioration of QoE on the terminal side can be avoided.
Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.
A part or all of the above-described embodiment can be described as in the following supplementary notes, but is not limited thereto.
(Appendix 1)
A terminal connected to the network and receiving the requested content from the content server via the network;
A packet receiving unit that receives a content file or a content stream for the requested content as a packet from the content server via the network;
A congestion detector that detects congestion of the network based on the packet received by the packet receiver;
A packet transmission control unit for notifying the content server of a request to change the file size of the content using the reverse direction of the network when the congestion detection unit detects congestion of the network;
A terminal comprising:
(Appendix 2)
The terminal according to appendix 1, wherein the congestion detection unit extracts congestion information from the received packet and detects congestion of the network.
(Appendix 3)
The terminal according to appendix 2, wherein the congestion detection unit extracts the congestion information by checking an ECN (Explicit Connection Notification) field of an IP (internet protocol) header portion of the received packet. .
(Appendix 4)
The request to change the file size of the content is HTTP (hyper transfer protocol), RTSP (Real Time Streaming Protocol) / SDP (Session Description Protocol RTP (SIP) (Session Initiation Protocol DTP / STP The terminal according to any one of appendices 1 to 3, wherein any one selected from the group of Control Protocol (RTP) and RTCP-APP (RTP Control Protocol-APPlication specific) is used.
(Appendix 5)
The packet transmission control unit
A bandwidth estimation unit that estimates a bandwidth of the network based on the received packet when the congestion detection unit detects congestion of the network;
A rate setting unit that calculates a file size to be changed based on the estimated bandwidth;
A packet transmission unit for notifying the content server of a request to change the file size of the content based on the calculated file size;
The terminal according to any one of supplementary notes 1 to 4, further comprising:
(Appendix 6)
A communication system comprising: the terminal according to any one of appendices 1 to 5, the content server, and a packet transfer control device that transfers the packet between the terminal and the content server via the network. .
(Appendix 7)
A terminal connected to the network and receiving the requested content from the content server via the network;
A packet receiving unit that receives a content file or a content stream for the requested content as a packet from the content server via the network;
A congestion detector that detects congestion of the network based on the packet received by the packet receiver;
A packet transmission control unit for notifying the content server of a request to change the content rate using the reverse direction of the network when the congestion detection unit detects congestion of the network;
A terminal comprising:
(Appendix 8)
The terminal according to appendix 7, wherein the congestion detection unit extracts congestion information from the received packet and detects congestion of the network.
(Appendix 9)
The terminal according to appendix 8, wherein the congestion detection unit extracts the congestion information by checking an ECN (Explicit Connection Notification) field of an IP (Internet protocol) header portion of the received packet. .
(Appendix 10)
The request to change the content rate is HTTP (hyper transfer protocol), RTSP (Real Time Streaming Protocol) / SDP (Session Description Protocol R (Protocol Protocol), SIP (Session Initiation Protocol R) (CTP). 10. The terminal according to any one of appendices 7 to 9, wherein any one selected from the group of Protocol) and RTCP-APP (RTP Control Protocol-APPlication specific) is used.
(Appendix 11)
The packet transmission control unit
A bandwidth estimation unit that estimates a bandwidth of the network based on the received packet when the congestion detection unit detects congestion of the network;
A rate setting unit that calculates a rate to be changed based on the estimated bandwidth;
A packet transmission unit for notifying the content server of a request to change the content rate based on the calculated rate;
The terminal according to any one of appendices 7 to 10, comprising:
(Appendix 12)
A communication system comprising: the terminal according to any one of appendices 7 to 11, the content server, and a packet transfer control device that transfers the packet between the terminal and the content server via the network. .
(Appendix 13)
A packet transmission / reception control method in a terminal connected to a network and receiving requested content from a content server via the network,
A packet receiving step of receiving a content file or a content stream for the requested content as a packet from the content server via the network;
A congestion detection step of detecting congestion of the network based on the received packet;
A packet transmission control step of notifying the content server of a request to change the file size of the content using the reverse direction of the network when congestion of the network is detected;
Packet transmission / reception control method including
(Appendix 14)
14. The packet transmission / reception control method according to appendix 13, wherein the congestion detection step detects congestion of the network by extracting congestion information from the received packet.
(Appendix 15)
15. The packet transmission / reception control method according to appendix 14, wherein the congestion detection step extracts the congestion information by checking an ECN (Explicit Connection Notification) field in an IP (Internet protocol) header portion of the received packet.
(Appendix 16)
The request to change the file size of the content is HTTP (hyper transfer protocol), RTSP (Real Time Streaming Protocol) / SDP (Session Description Protocol RTP (SIP) (Session Initiation Protocol DTP / STP The packet transmission / reception control method according to any one of appendices 13 to 15, using any one selected from the group of Control Protocol) and RTCP-APP (RTP Control Protocol-APPspecific).
(Appendix 17)
The packet transmission control step includes:
A bandwidth estimation step of estimating the bandwidth of the network based on the received packet when congestion of the network is detected;
A rate setting step for calculating a file size to be changed based on the estimated bandwidth;
A packet transmission step of notifying the content server of a request to change the file size of the content based on the calculated file size;
The packet transmission / reception control method according to any one of supplementary notes 13 to 16, including:
(Appendix 18)
A packet transmission / reception control method in a terminal connected to a network and receiving requested content from a content server via the network,
A packet receiving step of receiving a content file or a content stream for the requested content as a packet from the content server via the network;
A congestion detection step of detecting congestion of the network based on the received packet;
A packet transmission control step for notifying the content server of a request to change the content rate using the reverse direction of the network when congestion of the network is detected;
Packet transmission / reception control method including
(Appendix 19)
19. The packet transmission / reception control method according to appendix 18, wherein the congestion detection step detects congestion of the network by extracting congestion information from the received packet.
(Appendix 20)
20. The packet transmission / reception control method according to appendix 19, wherein the congestion detection step extracts the congestion information by checking an ECN (Explicit Connection Notification) field of an IP (Internet protocol) header portion of the received packet.
(Appendix 21)
The request to change the content rate is HTTP (hyper transfer protocol), RTSP (Real Time Streaming Protocol) / SDP (Session Description Protocol R (Protocol Protocol), SIP (Session Initiation Protocol R) (CTP). 21. The packet transmission / reception control method according to any one of appendices 18 to 20, using any one selected from a group of Protocol) and RTCP-APP (RTP Control Protocol-APPspecific).
(Appendix 22)
The packet transmission control step includes:
A bandwidth estimation step of estimating the bandwidth of the network based on the received packet when congestion of the network is detected;
A rate setting step for calculating a rate to be changed based on the estimated bandwidth;
A packet transmission step of notifying the content server of a request to change the content rate based on the calculated rate;
The packet transmission / reception control method according to any one of appendices 18 to 21, comprising:
(Appendix 23)
A computer-readable recording medium recording a packet transmission / reception control program that causes a computer that is a terminal connected to a network to receive requested content from a content server via the network, the packet transmission / reception control program comprising: On the computer,
A packet reception procedure for receiving a content file or a content stream for the requested content as a packet from the content server via the network;
A congestion detection procedure for detecting congestion of the network based on the received packet;
A packet transmission control procedure for notifying the content server of a request to change the file size of the content using the reverse direction of the network when congestion of the network is detected;
Recording medium that executes
(Appendix 24)
A computer-readable recording medium recording a packet transmission / reception control program that causes a computer that is a terminal connected to a network to receive requested content from a content server via the network, the packet transmission / reception control program comprising: On the computer,
A packet reception procedure for receiving a content file or a content stream for the requested content as a packet from the content server via the network;
A congestion detection procedure for detecting congestion of the network based on the received packet;
A packet transmission control procedure for notifying the content server of a request to change the content rate using the reverse direction of the network when congestion of the network is detected;
Recording medium that executes

140 Internet network 145 Content server 150 Mobile network 170, 170A Mobile terminal 190 Packet transfer control device 191 PCRF device 194 eNodeB device 250 Packet reception unit 251 Packet transmission unit 253 Video / audio / audio decoder 254 Rate setting unit 255 Congestion detection unit 257 Bandwidth Estimating section 258 Rate setting section This application claims priority based on Japanese Patent Application No. 2012-263957 filed on December 3, 2012, the entire disclosure of which is incorporated herein.

Claims

A terminal connected to the network and receiving the requested content from the content server via the network;
A packet receiving unit that receives a content file or a content stream for the requested content as a packet from the content server via the network;
A congestion detector that detects congestion of the network based on the packet received by the packet receiver;
A packet transmission control unit for notifying the content server of a request to change the file size of the content using the reverse direction of the network when the congestion detection unit detects congestion of the network;
A terminal comprising:
Requests to change the file size of the content are HTTP (hyper transfer protocol), RTSP (Real Time Streaming Protocol) / SDP (Session Description Protocol Protocol), SIP (Session Initiation Protocol TCP / STP). The terminal according to claim 1, wherein any one selected from a group of Control Protocol) and RTCP-APP (RTP Control Protocol-APPlication specific) is used.
The packet transmission control unit
A bandwidth estimation unit that estimates a bandwidth of the network based on the received packet when the congestion detection unit detects congestion of the network;
A rate setting unit that calculates a file size to be changed based on the estimated bandwidth;
A packet transmission unit for notifying the content server of a request to change the file size of the content based on the calculated file size;
The terminal according to claim 1, further comprising:
Communication including the terminal according to any one of claims 1 to 3, the content server, and a packet transfer control device that transfers the packet between the terminal and the content server via the network. system.
A terminal connected to the network and receiving the requested content from the content server via the network;
A packet receiving unit that receives a content file or a content stream for the requested content as a packet from the content server via the network;
A congestion detector that detects congestion of the network based on the packet received by the packet receiver;
A packet transmission control unit for notifying the content server of a request to change the content rate using the reverse direction of the network when the congestion detection unit detects congestion of the network;
A terminal comprising:
The request to change the content rate is HTTP (hyper transfer protocol), RTSP (Real Time Streaming Protocol) / SDP (Session Description Protocol Protocol, SIP (Session Initiation Protocol RDP), TCP (Session Initiation Protocol RDP). 6. The terminal according to claim 5, wherein any one selected from a group of Protocol) and RTCP-APP (RTP Control Protocol-APPlication specific) is used.
The packet transmission control unit
A bandwidth estimation unit that estimates a bandwidth of the network based on the received packet when the congestion detection unit detects congestion of the network;
A rate setting unit that calculates a rate to be changed based on the estimated bandwidth;
A packet transmission unit for notifying the content server of a request to change the content rate based on the calculated rate;
The terminal according to claim 5 or 6, characterized by comprising:
Communication including the terminal according to any one of claims 5 to 7, the content server, and a packet transfer control device that transfers the packet between the terminal and the content server via the network. system.
A packet transmission / reception control method in a terminal connected to a network and receiving requested content from a content server via the network,
A packet receiving step of receiving a content file or a content stream for the requested content as a packet from the content server via the network;
A congestion detection step of detecting congestion of the network based on the received packet;
A packet transmission control step of notifying the content server of a request to change the file size of the content using the reverse direction of the network when congestion of the network is detected;
Packet transmission / reception control method including
A packet transmission / reception control method in a terminal connected to a network and receiving requested content from a content server via the network,
A packet receiving step of receiving a content file or a content stream for the requested content as a packet from the content server via the network;
A congestion detection step of detecting congestion of the network based on the received packet;
A packet transmission control step for notifying the content server of a request to change the content rate using the reverse direction of the network when congestion of the network is detected;
Packet transmission / reception control method including