KR100823263B1 - Method and apparatus for securing a Quality of Service - Google Patents

Abstract

The present invention relates to a method of guaranteeing quality of service (QoS) using a communication protocol, and the method of guaranteeing QoS of a receiving side receiving data from a transmitting side according to the present invention changes the communication environment as the receiving communication environment is changed. Generating information indicating that; And transmitting information indicating a communication environment to a transmitting side. According to the present invention, information on a resource of a receiving side and a link are exchanged by exchanging information representing a communication environment using a communication protocol between a receiving side and a transmitting end. The characteristics, the link characteristics on the communication path, and the like can be informed to the transmitting side, thereby ensuring the QoS of data communication between the receiving side and the transmitting side.

Link characteristics, QoS, protocol, communication environment, resources

Description

Method and apparatus for securing a Quality of Service

1 illustrates a data communication session according to a heterogeneous inter-network handover.

2 illustrates a data communication session according to a handover between heterogeneous networks.

3 is a flowchart illustrating a QoS guarantee method of a receiving side according to an exemplary embodiment of the present invention.

4A is a flowchart of a QoS guaranteeing method at a receiving side according to an exemplary embodiment of the present invention.

4B is a flowchart of a QoS guaranteeing method at a receiving side according to an exemplary embodiment of the present invention.

5 is a flowchart illustrating a QoS guarantee method of a transmitter according to an exemplary embodiment of the present invention.

6A illustrates a data communication session of a method of guaranteeing QoS in accordance with one preferred embodiment of the present invention.

6B illustrates a data communication session of a method of guaranteeing QoS in accordance with a preferred embodiment of the present invention.

7 is a flowchart illustrating a QoS guarantee method considering link characteristics on a transmission path according to an exemplary embodiment of the present invention.

8 illustrates a data communication session of a QoS guarantee method considering link characteristics on a transmission path according to an exemplary embodiment of the present invention.

9 illustrates a packet structure including information representing a communication environment according to an exemplary embodiment of the present invention.

10 is a block diagram of an apparatus for guaranteeing QoS of a receiving side according to an exemplary embodiment of the present invention.

11 is a block diagram of an apparatus for guaranteeing QoS of a transmitting side according to an embodiment of the present invention.

The present invention relates to an apparatus and method for guaranteeing QoS using a communication protocol, and more particularly, to a link characteristic or data processing using a communication protocol between a receiving side and a transmitting side when a communication environment of data communication between a receiving side and a transmitting side changes. The present invention relates to a method and apparatus for guaranteeing a quality of service (QoS) of data communication through the exchange of information indicative of necessary resources.

With the development of wired and wireless communication technology, the types of wired and wireless communication services supporting multimedia communication and their communication standards have diversified. In particular, as the transmission speed of data is gradually improved, more and more services are provided for providing real-time streaming of music or video through wired and wireless communication. In this case, the technology that allows the service user to continuously listen to music or watch video is the most important. Especially, when the communication environment changes as follows, the importance of the QoS guarantee method for the continuous data communication between the receiving side and the transmitting side is It is highlighted.

As shown in FIG. 1, when the mobile terminal of the receiving side 110 is located in the WLAN network 130 having the maximum data rate of 2 Mbps and moves to the WCDMA network 140 having the maximum data rate of 384 Kbps. Assume Here, the transmitting side 120 is transmitting data at 1 Mbps in a 2 Mbps wireless communication network, and since the receiving terminal does not know the link characteristics of the moving network, it continues after the handover 102 of the receiving terminal. If data is transmitted 103 assuming the same transmission rate, the receiving terminal cannot receive all the data transmitted by the transmitting side. Therefore, if the data being transmitted is streaming data of music or video, it is impossible for the receiver to continuously listen to music or watch a video in real time.

On the contrary, as shown in FIG. 2, it is assumed that the receiving side 210 moves from the WCDMA network 230 having the maximum data transfer rate of 384 Kbps to the WLAN network 240 having the maximum data transfer rate of 2 Mbps. Here, the transmitting side is transmitting data 201 at the transmission rate of 384 Kbps before the handover 202, and even after the handover 202 of the receiving terminal because the receiving terminal does not know the link characteristics of the moving network. If data is continuously transmitted 203 at the same data rate, inefficiency of transmitting data at a data rate of 156 Kbps occurs in a WLAN network having a maximum data rate of 2 Mbps.

1 or 2, in addition to handover between heterogeneous networks, as well as handover between homogeneous networks, the link characteristics in the network after the handover may be different from the link characteristics before the handover. If the network after the handover has more users than the network before the handover, each user on the network will have to communicate slowly. In addition, if the bit error rate in the network after the handover is significantly higher than the network before the handover, it is necessary to lower the data transmission rate to transmit the data in order to reduce the bit error rate. On the contrary, when the user handovers to a network having a low bit error rate or a low bit error rate, data communication can be performed at a faster transmission rate.

In addition, even when the receiving side communicates in the same network without handover between the networks, the data transmission speed does not change even though the receiving side belongs to the same network due to the change of the number of users on the network and the change of the data communication environment. There may be.

Information about the change of resources available for processing the data being received by the receiving terminal may also affect the QoS of data communication with the transmitting terminal. If the hardware characteristics such as CPU, memory, etc. that the receiving terminal can allocate to process the data being received have changed, and the sender continues to transmit data despite being unable to process the data currently being received, The receiving side cannot normally receive data. The same applies to a case in which a music or video encoded in a manner that the receiver cannot process is transmitted to the receiver without knowing it.

In the above-mentioned cases, if the receiver transmits information indicating a change in data transmission speed or resources of the network to which the receiver belongs, and the sender receives and transmits data in accordance with the changed communication environment, the QoS of data communication is reduced. Can be guaranteed. For example, in order to enable real-time service even at a slow data transmission speed in a slow transmission network, low quality, low quality music or video data may be transmitted as compared to a fast network. In addition, in a high-speed network, a higher quality, higher quality music or video data may be transmitted than a slow network to enable a higher quality streaming service. In addition, if the receiving side can allocate more CPU or memory to process the data transmitted by the transmitting side, better quality data communication is possible by transmitting higher quality, higher quality music or image data than before the change.

Conventional techniques for changing the size of data to be transmitted in accordance with the communication environment of the receiving side is a sliding window congestion control of the TCP protocol. The receiver sends an ACK signal indicating that the transmitter has received the data without error. If a normal ACK signal response arrives at the transmitter, the transmitter increases the size of data transmitted at one time. . On the contrary, if the ACK signal does not arrive at the sender, the sender reduces the size of data transmitted at one time. Since the data transmission rate can be adjusted according to the improvement or deterioration of the link characteristics of the receiver, the transmission function is performed in consideration of the link characteristics of the receiver. However, sliding window congestion control takes considerable time to transmit data in accordance with the receiving side's improved or deteriorated link characteristics of the receiving side, thus resulting in inefficient use of the link by that time delay.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a method and apparatus for guaranteeing QoS in data communication between a receiving side and a transmitting side despite a change in link characteristics of a receiving side or resource characteristics available for processing data processing. The present invention provides a computer readable recording medium having recorded thereon a program for executing the method on a computer.

According to the present invention for solving the technical problem, the QoS guarantee method of the receiving side receiving data from the transmitting side comprises the steps of generating information indicating the changed communication environment as the communication environment of the receiving side is changed; And transmitting the generated information to the transmitting side.

According to a more preferred embodiment according to the present invention, the information representing the communication environment is a resource available for processing information indicative of link characteristics of the changed communication environment and / or data being received by the receiving side in the changed communication environment. (resource).

According to a more preferred embodiment of the present invention, the information indicating the link characteristics is information indicating a link characteristic of a second network when the receiver makes a handover from the first network to the second network. do.

According to a more preferred embodiment according to the invention, the step of transmitting is characterized in that for transmitting the link characteristic information of the second network before handover.

According to a more preferred embodiment of the present invention, the QoS guarantee method further comprises the step of performing a handover when receiving response information for the information indicating the link characteristics from the transmitting side.

According to a more preferred embodiment of the present invention, the transmitting step is characterized in that after the handover, information indicating the link characteristics of the second network is transmitted to the transmitting side.

According to a more preferred embodiment of the present invention, the information representing the resource is characterized in that it represents at least one of the CPU, available codec, display resolution, memory and the size of the receiving buffer of the receiving device.

According to the present invention for solving the above technical problem, the QoS guarantee device of the receiving side receiving data from the transmitting side generates communication environment information for generating information indicating the changed communication environment as the communication environment of the receiving side is changed. part; And a transmitting unit for transmitting the information indicating the communication environment to the transmitting side.

According to a more preferred embodiment according to the present invention, the information representing the communication environment is a resource available for processing information indicating link characteristics of the changed communication environment and / or data being received by the receiving side in the changed communication environment. (resource).

According to the present invention for solving the technical problem, the QoS guarantee method of the transmitting side transmitting data to the receiving side comprises the steps of: receiving information indicating the communication environment of the receiving side from the receiving side; Adjusting the QoS for transmission of the data according to the received information.

According to a more preferred embodiment according to the invention, the information representing the communication environment is information indicating the link characteristics of the changed communication environment and / or resources available for processing the data being received by the receiving side in the changed communication environment ( resource).

According to a more preferred embodiment according to the present invention, the QoS guarantee method comprises the steps of: generating response information indicating that the QoS for the data transmission is adjusted according to the information representing the link characteristics; And transmitting the response information to the receiving side.

According to the present invention for solving the above technical problem, the QoS guarantee apparatus of the transmitting side transmitting data to the receiving side includes a communication environment information receiving unit for receiving information indicating the communication environment; It includes a QoS control unit for adjusting the QoS according to the information indicating the communication environment.

According to a more preferred embodiment of the present invention, the QoS guarantee device comprises: a response information generator for generating response information indicating that QoS is adjusted according to information representing the communication environment; The apparatus may further include a transmitting unit which transmits the response information to the receiving side.

SUMMARY OF THE INVENTION In order to solve the above technical problem, the present invention provides a computer readable recording medium having recorded thereon a program for executing the above QoS guarantee method in a computer.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a flowchart illustrating a QoS guarantee method according to a link characteristic of a receiver according to the present invention.

In step 301, the receiving side detects a link characteristic of the network. In general, a link characteristic may be detected by analyzing a transmission signal from an access point or a router of a network to which a receiver belongs. An access point means an AP in the case of a wireless LAN, and a base station in mobile communication such as CDMA and WCDMA. When viewed from the receiving side by a detection method such as a network driver interface specification (NDIS) of a Windows computer operating system, the link characteristics can be detected from a wired station or a wireless station that is first connected on the link to the transmitting side. have.

The detected link characteristics may include information on the strength of the data transmission signal, a data transmission rate, a bit error rate (BER), and a wireless communication standard in the case of a wireless communication network. In one embodiment, when the receiving terminal is receiving data on the WLAN network, by analyzing the beacon signal transmitted periodically by the access point (AP) or other terminals on the network, the link characteristics of the network Can be detected.

In case of a handover between homogeneous / heterogeneous networks in which the receiving side moves from the first network to the second network, information on link characteristics of the second network is detected.

In an embodiment, the method may further include determining a link state according to the link characteristic (not shown). The detected link characteristics may include information by various factors as described above, and it may be inefficient to transmit all of them to the transmitting side. Therefore, by dividing the communication environment in the receiving network into a plurality of levels according to a good degree, and assigning coefficients according to each level and transmitting only coefficients, the transmitting side can predict the link characteristics of the receiving side using only the transmitted coefficients. Can be.

The determining of the link state (not shown) does not necessarily need to be performed at the receiving side, and may transmit only the link characteristics detected in step 301 to the transmitting side and perform the determination of the link state based on the transmitting side.

In step 302, information representing the link characteristic detected in step 301 (hereinafter referred to as link information) is generated. The link information may be periodically generated and transmitted to the transmitter in step 303, or may be generated and transmitted in step 303 only when there is a change in the link characteristic.

In the case where the link information is generated only when there is a change in the link characteristic, if there is no change in the link characteristic, data is continuously received without a change in the method of receiving the current data. However, if there is a change in the link characteristic, steps 302 to 307 are performed.

In step 304, it is determined whether response information to which the transmitting side responds to the link information transmitted by the receiving side is transmitted from the transmitting side. If the transmitting side does not transmit the packet including the response information, the flow returns to step 303 to transmit the changed link information to the transmitting side. In contrast, if the transmitting side transmits a packet including the response information, the receiving side proceeds to the next step (step 306) and determines whether or not it is a handover.

Steps 305 to 306 are steps in which the receiving side receiving the response information of the transmitting side performs the handover. In step 305, if the change in the link characteristic is caused by handover, since the response information of the transmitting side has already been received, handover is performed (step 306), and data reception (step 307) is started. However, if the change of the link characteristic is only a change of link information on the same network and not a handover, no handover is performed, and data is received according to the changed link characteristic (step 307).

As described above, even in handover between homogeneous networks, the link characteristics may be different because the number of users, signal strength, bit error rate, etc. on the network before or after the handover are different. Thus, the handover in step 305 includes both handovers between homogeneous / heterogeneous networks.

4A is a flowchart illustrating a method of transmitting information on a link characteristic after handover in a QoS guarantee method of a receiving side according to the present invention.

In step 401, the receiver that detects handover from the first network to the second network performs the handover in step 402.

After the handover, the link characteristic of the second network is detected in step 403. The link characteristics detected as described above may include information on the strength of the data transmission signal on the second network, the data transmission rate, the bit error rate, and the wireless communication standard in the case of a wireless communication network.

In step 404, information on the link characteristic detected in step 404 is generated using a communication protocol. Similar to step 302 of FIG. 3, link information may be periodically generated and transmitted through step 406, or a packet may be generated only when there is a change in link information.

When link information is generated only when there is a change in the link characteristic, if there is no change in the link characteristic, data is continuously received without a change in the method of receiving current data. However, if there is a change in the link characteristic, steps 404 to 407 are performed.

In step 406, it is determined whether the response information of the transmitting side has been transmitted with respect to the link information transmitted by the receiving side. If the response information of the transmitting side has not been transmitted, link information is transmitted again (step 405). If the sending side transmits the response information, it receives data in step 407.

The QoS guaranteeing method of the receiving side shown in FIGS. 3 and 4A does not need to be independently performed in each embodiment. Even when link information is transmitted to the transmitting side before the handover, the link information is repeatedly repeated after the handover. Can transmit In addition, the link information should be transmitted before the handover, but the link information is transmitted after the handover only when the link information cannot be transmitted before the handover due to an unavoidable reason such as a sudden handover. You may.

4B is a flowchart illustrating a QoS guarantee method of a receiver according to a change in resource characteristics required for data processing on the receiver according to the present invention. The communication environment information may include not only the link characteristic information shown in FIGS. 3 and 4A but also information on a resource available for processing data being received by the receiver. A method for guaranteeing QoS of data communication is described.

In step 411, the receiving side generates information representing a resource available for processing the data being received. Information representing available resources includes information about hardware characteristics such as CPU, memory, size of receive buffer, display resolution, etc. available to the receiving terminal to process the data being received and available at the receiving terminal. Information about software characteristics such as a video / audio codec may be included. In addition to the information indicating the hardware / software characteristics listed above, the characteristics of the terminal that may affect the data communication environment of the receiving side and the transmitting side may be included in the information indicating available resources and transmitted to the transmitting side.

In step 412, information indicating the resource generated in step 411 is transmitted to the sender. Unlike in the case of transmitting the link characteristic information, if there is a change in the information indicating the resource regardless of handover, it is transmitted to the transmitting side. In addition to the change, the information indicating the resource may be periodically transmitted to the transmitting side.

In step 413, it is determined whether the response information for the information indicating the resource transmitted to the transmitter in step 412 is received from the transmitter. If response information has been received, data is received via step 414 according to the changed QoS. If no response information is received, the flow returns to step 412 to transmit information indicating available resources.

5 is a flowchart illustrating a QoS guarantee method of a transmitting side according to the present invention.

In step 501, the transmitter determines whether information indicating a communication environment transmitted by the receiver is received. If the information is received, the QoS is adjusted for data transmission in step 502. If the information is not received, since there is no change in the link characteristics or the resource state available to the receiving side, data is continuously transmitted to the receiving side through step 504.

In step 502, the transmitting side adjusts the QoS of data transmission according to the communication environment information transmitted by the receiving side. If the bit error rate of the receiver is increased due to deterioration of the link characteristics, the forward error correction method may be changed to a method more resistant to errors. Also, if the transmission speed is slowed according to the change of the data transmission speed of the receiver, the encoding method of the data to be transmitted is adjusted to reduce the number of frames per second of video or music data, to lower the resolution, or to have a higher compression rate. It is possible to change such as. On the contrary, if the data transmission speed is increased, QoS control methods such as increasing the number of frames per second, increasing the resolution, or switching to a low compression scheme are used. The transmitting side may have various quality contents, and may transmit high quality or low quality contents according to deterioration or improvement of the receiving side link characteristics. There is no restriction on the method of adjusting the QoS, and all methods of changing the quality of data being transmitted in accordance with the change of the receiving communication environment may be used in adjusting the QoS.

In step 503, the sender generates response information indicating that it is ready to transmit data according to the changed communication environment information. The response information may be configured by simply setting a specific bit in the data packet transmitted to the receiver to '0' or '1' to simply indicate whether the transmitter is ready. In addition, when the response information needs to be specifically configured, such as when the encoding method and the decoding method correspond to each other and the receiving side needs to know the encoding method of the data transmitted by the transmitting side, the encoding method and format of the data that the transmitting side intends to transmit. The response information may be configured by displaying the size, size, and the like in detail. Encoding methods include information such as frames per second, resolution, compression rate, and forward error correction.

In step 504, the packet including the response information generated in step 503 is transmitted to the receiving side, and data is transmitted (step 505) according to the changed link information of the receiving side.

When a period from the start of data communication between the transmitting side and the receiving side until the completion of communication is referred to as a session, FIG. 6A illustrates a session for transmitting and receiving link information during handover between homogeneous and heterogeneous networks according to the present invention. do.

It is assumed that the receiving side 610 receives data (601 to 602) from the transmitting side 620 at a transmission rate of 100 Mbps in the network 630 having a data transmission rate of 100 Mbps. As the receiving side 610 moves to the network 640 whose data transmission rate is 156 Kbps, the receiving side 610 detects the link characteristics of the changed network. Link information is generated at the receiving side according to the detected link characteristic, and transmitted (603) to the transmitting side. The transmitting side 620 receiving the packet transmits the response information to the receiving side 604, and the receiving side receives the response information and performs the handover. Upon completion of steps 603 to 604, data transmission (605 to 606) is performed at a transmission rate of 156 Kbps according to the changed link characteristics.

FIG. 6A illustrates a case in which the receiving side 610 moves from the 630 network to the 640 network when the data transmission rate is changed by the handover of the homogeneous / heterogeneous network.

FIG. 6B illustrates a case where the data transmission rate is changed while the receiving side 650 is performing data communication with the transmitting side 660 through the same network, that is, the same base station or access point, without handover between homogeneous and heterogeneous networks. .

A change 653 occurs in the data transmission rate while the receiving side 650 is receiving data transmissions 651 to 652 from the transmitting side 660 at 100 Mbps. The change in data transmission rate may be caused by a change in the strength of the signal or a change in the user connected to the same base station or access point.

Accordingly, the receiving side 650 transmits link information indicating the characteristics of the changed link to the transmitting side 660 (654), and the transmitting side 660 transmits the response information (655). After the process of 654 to 655 is completed, data is transmitted (656 to 657) at a data transmission rate of 156 Kbps according to the changed link information.

6A to 6B show the case where the data transmission rate is changed. However, in addition to a change in the data transmission rate, a change in the link characteristics in data transmission between the receiving side and the transmitting side, such as an increase or decrease in the bit error rate due to jamming, a deterioration or improvement of the communication environment due to a change in signal strength, and the like. Changes to all the elements that cause the ACK may be included in the link information and transmitted.

By using the above-described methods, even if the transmitting side transmits the link information to the transmitting side and the transmitting side transmits the data accordingly, the link information transmitted by the receiving side to the transmitting side is not limited to the access point directly connected to the receiving terminal. Only link information with the router is transmitted to the sender. However, data communication between the receiving side and the transmitting side may be affected by link characteristics on the transmission path such as a router or a repeater on the transmission path from the receiving side to the transmitting side. Therefore, there is a need for a method for transmitting data in consideration of link information on a transmission path.

7 is a flowchart illustrating a QoS guarantee method considering link information on a transmission path according to the present invention.

In step 701, the access node relaying the data receives link information transmitted from the receiving end to the transmitting end. The link information transmitted from the receiver to the transmitter includes only link information on the link characteristics of the access node that directly exchanges data with the receiver.

The access node relaying the data in step 702 determines whether addition or correction is necessary to the link information received in step 701. If the current access node that receives the link information transmitted by the receiver cannot transmit data according to the receiver link information, link information is added or modified (step 703) to generate link information in consideration of the link characteristics on the transmission path. .

8 illustrates a link information transmission / reception session including link information on a transmission path according to the present invention.

In the network 850 having the data transmission rate of 156 Kbps, the receiving side 810 forms a link with the transmitting side 840 through the router 820 having a data transmission rate of 5 Mbps and the router 830 having a data transmission rate of 50 Mbps. Assume a case where data is transmitted (801 to 802) from the transmitting side 840 at a rate of 156 Kbps. As the receiving side moves from the 850 network to the 860 network, the data rate has been increased from 156 Kbps to 100 Mbps, so the receiving side 810 generates link information for the data rate of 100 Mbps and transmits it 803. However, since the 5Mbps router 820 only supports a transmission speed of 5Mbps, even if the transmitting side 840 transmits data at a rate of 100Mbps, the receiving side 810 may not receive it properly. Accordingly, the 5 Mbps router 820 modifies and transmits 804 the link information transmitted to the transmitting side 840 according to the data transmission rate of 5 Mbps.

Since 50 Mbps router 830, which has received link information from the 5 Mbps router 820, has already set link information according to a 5 Mbps data rate lower than the 50 Mbps data rate supported by the router 830, separate link information The link information is transmitted 805 to the sender without any modification to the transmitter.

As a result, the transmitting side transmits data at a transmission rate of 5 Mbps (806 to 807) in accordance with the link information 805 considering the link characteristics on the transmission path as a whole, not the link information 803 transmitted by the receiving side. QoS in data transmission between transmitting sides is guaranteed.

The routers 820 to 830 on the transmission path do not modify the link information transmitted by the receiver, but simply add and transmit the link information according to the data transmission rate that they can support. The embodiment may be configured in such a manner that the information can be compared and judged so that data can be transmitted at an optimal data transmission rate.

As shown in FIG. 8, the link characteristics may be changed not only when the data transmission speed is increased or decreased, but also when the bit error rate is increased or decreased due to radio interference, or when the communication environment is deteriorated or improved due to a weak signal. Any element change that causes a change in the data transmission state of the sender may be included.

There is no restriction on the method of generating and transmitting the communication environment information, but in general, since the data transmission of the receiving side and the transmitting side is performed based on the packet structure, the link information is included in the data packet using a communication protocol. Can be created and transmitted.

A packet for general data communication is divided into a communication protocol field 910 indicating a data communication protocol of a receiving side and a transmitting side as shown in FIG. 9 and a payload field 920 which is data to be transmitted. The communication protocol field 910 includes various communication protocol headers of various layers. For example, protocol headers such as IPv4, IPv6 of a network layer or TCP, UDP of a transport layer are included. In addition, various communication protocols are defined in an application layer, a presentation layer, a session layer, a datalink layer, and a physical layer.

The communication environment information according to the present invention may be inserted (not shown) in some of the above-described communication protocol fields 930 to 960 and transmitted, or may be defined as a separate protocol for transmitting communication environment information. It may be inserted 970 into 910.

10 shows an apparatus for guaranteeing QoS of a receiving side according to the present invention. The QoS guaranteeing apparatus 1000 of the receiving side is composed of a link characteristic detector 1020, a communication environment information generator 1030, and a transmitter 1040.

The link characteristic detection unit 1020 detects the link characteristic from the connection node 1010 to which the receiving side is connected, that is, an access point or a router. Link information to be detected is generated through link information generation unit 1030 to be transmitted to the transmitter. According to an embodiment of the present disclosure, the communication environment information generation unit 1030 may generate communication environment information by creating and inserting a separate field on the communication protocol field 910 of the data packet, or inserting it into a part of an existing protocol. Can be.

The transmitter 1040 transmits the communication environment information generated by the communication environment information generator 1030 to the transmitter 1050.

11 shows an apparatus 1100 for guaranteeing QoS of a transmitting side according to the present invention.

The QoS guaranteeing apparatus 1100 of the transmitting side is composed of a communication environment information receiving unit 1120, a QoS adjusting unit 1130, a response information generating unit 1140, and a transmitting unit 1150.

The communication environment information receiver 1120 receives communication environment information transmitted by the receiver 1110, extracts link characteristics, and transmits the link characteristics to the QoS adjuster 1130.

The QoS adjuster 1130 prepares to transmit data in accordance with the changed communication environment of the receiver by adjusting the size, encoding method, format, etc. of data to be transmitted to the receiver.

The response generator 1140 generates a packet including response information indicating that it is ready to transmit data according to the changed communication environment. The response information may be configured by simply setting a specific bit in the data packet transmitted to the receiver to '0' or '1' to simply indicate whether the transmitter is ready or not. Response information may also be configured by a method of specifically indicating an encoding method, a format, and a size.

The transmitter transmits the response information generated by the response information generator 1140 to the receiver 1110.

As described above, although the present invention has been described by way of limited embodiments and drawings, the present invention is not limited to the above-described embodiments, which can be variously modified and modified by those skilled in the art to which the present invention pertains. Modifications are possible. Accordingly, the spirit of the invention should be understood only by the claims set forth below, and all equivalent or equivalent modifications will fall within the scope of the invention. In addition, the system according to the present invention can be embodied as computer readable codes on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of the recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and also include a carrier wave (for example, transmission through the Internet). The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

According to the present invention, QoS for data communication between a receiving side and a transmitting side is transmitted by transmitting information on a change of a link characteristic on a transmission path from a receiving side or a receiving side to a transmitting side to a transmitting side, and the transmitting side transmitting data according to the changed link characteristic. Can be guaranteed.

Claims (25)

In the QoS guarantee method of the said receiving side which is receiving data from the sending side which has the data to transmit to a receiving side, At least one of information indicating a link characteristic of the changed communication environment and information indicating a resource available for processing the data being received by the receiving side in the changed communication environment as the communication environment of the receiving side is changed; Generating a; And transmitting the generated information to the transmitting side. delete The method of claim 1, wherein the information representing the link characteristics is In case of a handover in which the receiving side moves from the first network to the second network, the QoS guarantee method is information indicating a link characteristic of the second network. The method of claim 3, wherein the transmitting step And transmitting information indicative of link characteristics of the second network before the handover. The method of claim 4, wherein And performing handover when receiving response information on the information indicating the link characteristic from the transmitting side. The method of claim 3, wherein the transmitting step And transmitting information indicative of link characteristics of the second network after the handover. The method of claim 1, wherein the information representing the link characteristics is QoS guarantee method, characterized in that it comprises information on the link characteristics added or modified on the transmission path from the receiving side to the transmitting side. The method of claim 1, And detecting the link characteristic from an access point or a router of a network to which the receiving side belongs. The method of claim 1, wherein the information representing the resource is And at least one of the CPU of the receiving device, the available codec, the display resolution, the memory, and the size of the receiving buffer. In the QoS guarantee apparatus of the said receiving side which is receiving data from the sending side which has the data to transmit to a receiving side, At least one of information indicating a link characteristic of the changed communication environment and information indicating a resource available for processing the data being received by the receiving side in the changed communication environment as the communication environment of the receiving side is changed; Communication environment information generation unit for generating a; QoS guarantee apparatus comprising a transmitting unit for transmitting the generated information to the transmitting side. delete The method of claim 10, wherein the information representing the link characteristics is QoS guarantee apparatus, characterized in that it comprises information on the link characteristics added or modified on the transmission path from the receiving side to the transmitting side. The method of claim 10, And a link characteristic detector for detecting the link characteristic from an access point or a router of a network to which the receiver belongs. In the QoS guarantee method of the sending side which holds the data to transmit to the receiving side which is transmitting data to the receiving side, Receiving at least one of information indicating a link characteristic of the receiving side communication environment and information indicating a resource available for processing the data being received by the receiving side in the communication environment from the receiving side; Adjusting the QoS for the transmission of the data according to the received information. delete 15. The method of claim 14, wherein adjusting the QoS is And a method of changing a forward error correction method of data to be transmitted to a receiver according to a change of a bit error rate included in the information indicating the link characteristic. 15. The method of claim 14, wherein adjusting the QoS is And at least one of a frame rate per second, a resolution, and a compression rate of data transmitted to a receiving side according to a change of a data transmission rate included in the information indicating the link characteristic. The method of claim 14, Generating response information indicating that QoS for the data transmission is adjusted according to the information representing the communication environment; And transmitting the response information to the receiving side. In the QoS guarantee apparatus of the sending side which holds the data to transmit to the receiving side which is transmitting data to a receiving side, Communication environment information for receiving at least one of information indicating a link characteristic of the receiving side communication environment and information indicating a resource available for processing the data being received by the receiving side in the communication environment from the receiving side; Receiving unit; QoS guarantee device for adjusting the QoS in accordance with the received information. delete 20. The system of claim 19, wherein the QoS control unit And a method of changing a forward error correction method of data to be transmitted to a receiver according to the change information of the bit error rate included in the information indicating the transmitted link characteristic. 20. The system of claim 19, wherein the QoS control unit And at least one of a frame rate per second, a resolution, and a compression rate of data transmitted to a receiving side according to the change information of the data transmission rate included in the information indicating the transmitted link characteristic. The method of claim 19, A response information generator for generating response information indicating that QoS is adjusted according to the information representing the communication environment; QoS guarantee device further comprises transmitting the response information to the receiving side. A computer readable program recording a program for executing the method of any one of claims 1, 3, 4, 5, 6, 7, 8, or 9 on a computer. Record carrier. 19. A computer readable recording medium having recorded thereon a program for executing the method of any one of claims 14, 16, 17 or 18 on a computer.

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