KR20110047758A - Method, system and computer readable recording medium for transmitting multimedia data based on network coding - Google Patents

Abstract

The present invention relates to a method, a system and a computer readable recording medium for transmitting multimedia data based on network coding. According to an aspect of the present invention, there is provided a method for transmitting data based on network coding, comprising: (a) classifying information into a plurality of groups based on a priority according to a request of a user terminal device; Transmitting, to the user terminal device, a group having a higher priority than a predetermined threshold among the groups of (c), and (c) network coding a group having a lower priority than the predetermined threshold among the plurality of groups. Provided is a method comprising transmitting to the user terminal device. Accordingly, another object of the present invention is to classify information according to priority and to transmit the classified information as information that is not network coded and network coded according to priority.

Description

METHOOD, SYSTEM AND COMPUTER-READABLE RECORDING MEDIUM FOR PROVIDING MULTIMEDIA DATA BASED ON NETWORK CODING}

The present invention relates to a method, a system and a computer readable recording medium for transmitting multimedia data based on network coding. More specifically, by classifying and providing information that is not network coded and network coded according to the priority (for example, user's request) of information (for example, content), A method and system and a computer readable recording medium can improve transmission efficiency.

In recent years, the transmission of multimedia data streams over the Internet such as online music and radio broadcasts, video on demand (VOD), and Internet Protocol Television (IPTV) services has increased significantly.

In particular, an IPTV service that can be used simultaneously by residents in a wide area can be a class of next-generation communication traffic of IP communication. However, even if such IPTV is used by millions of users using stream data of more than hundreds of kbps at the same time, transmission of media data through the existing Internet backbone network can cause many problems. This is due to the unique characteristics of media stream data such as high data rates and consequent transmission delays and packet loss, which are different from normal data transmission.

Therefore, if the media stream data is transmitted through an internet network having limited and variable bandwidth, it is difficult to provide high quality multimedia data to the user.

In order to solve this problem, recently, studies have been actively conducted to apply network coding (NC) for the purpose of efficient resource allocation, throughput improvement, and transmission error minimization for multimedia stream application services.

The general network coding studied so far is as follows.

1 is a block diagram showing a transmission method of a general network coding system.

Referring to FIG. 1, by distributing data through a plurality of multicast paths formed between the same source and destination nodes, a server S may distribute and transmit data a and b to node A and node B, respectively. . For this data transmission, node A, node C, and D are used as relay nodes for data a, and node B, node C, and D can be used as relay nodes for data b.

At this time, the node C (overlapping node) receiving the data a and b outputs the data a and b by network coding, and the node T1 and the node T2, which are the destinations through the node D, simultaneously receive the data transmission times. Can be reduced.

b 데이터와, 다른 경로인 노드 A를 통해 수신한 데이터 a를 XOR 연산함으로써 데이터 b를 얻을 수 있고, 이와 동일한 원리로, 목적지인 노드 T2는 노드D를 통해 수신한 데이터 a

b 데이터와, 다른 경로인 노드 B를 통해 수신한 데이터 b를 XOR 연산함으로써 데이터 a를 얻을 수 있다. 따라서, 목적지인 노드 T1, T2는 산출된 a와 b를 이용하여 소스인 노드 S의 데이터를 효율적으로 복원할 수 있다.On the other hand, node T1, which is a destination for receiving the data, receives data a received through node D.

The data b can be obtained by performing an XOR operation on the b data and the data a received through the node A, which is another path. In the same principle, the destination node T2 receives the data a received through the node D.

The data a can be obtained by performing an XOR operation on the b data and the data b received through the node B which is another path. Therefore, the nodes T1 and T2 as the destination can efficiently restore the data of the node S as the source using the calculated a and b.

However, in order to apply the current network coding (NC) technology to a wireless communication network, the problem of link errors due to inter-layer optimization, channel attenuation, etc. should also be taken into consideration, and is not composed of a simple network topology as shown in FIG. It should also be considered.

As such, there are different considerations in the mobile IPTV service than the conventional network coding scheme for applying network coding.

The first challenge is to determine which layer of the current OSI protocol stack should handle network coding. The layer of the OSI protocol to perform network coding may vary depending on the environment of the network and the application to be applied. Most of the network coding proposed so far is performed between the MAC and IP layers. This is because each node does not need to send data to the Transport or Application layers for encoding and decoding.

However, this method is not suitable in an IP-based service environment such as IPTV. When network coding is applied between the MAC and the IP layers, the packet transmission start nodes periodically process the decoding and encoding of the network coding to confirm the IP of the transmitted data, which may result in a packet processing delay of the entire node. Because there is.

Next, the second challenge is data asynchronousness due to packet loss and delay at each node of the network and variability in network connection status. Real-time video stream transmission services such as IPTV are sensitive to packet delay and hence data synchronization. In particular, it is not easy to apply network coding for a network connection state that changes frequently. In order to overcome this difficulty, researches on applying network coding in a real environment using random coding, packet tagging, and buffering have been carried out.

First, in the case of random coding, since network coding is possible only when the connection state of the entire network is known, it is not a suitable method in a real environment in which the connection state of the network changes frequently. However, network coding only needs to determine a local coding vector component at a given network node at random and perform linear combining only. This is because random linear coupling performed in this way is necessary to apply network coding in a real network.

Next, in the case of packet tagging, a global coding vector is attached to all data passing through the node and transmitted. Therefore, no additional operation is needed to obtain the network connection status or decoding matrix at the destination node.

Finally, in the case of network coding using buffering, the header of each packet is assigned generation (unit time for generating data symbols at the source node), and then packets arriving at each node are synchronized using buffering according to the generation order. Can be.

However, as described above, the network coding (NC) technique also has a limitation that the user terminal device can restore the original information by decoding it only when all the packets are transmitted from the server. Therefore, there is a demand for the development of a new data transmission method that can further improve the transmission efficiency of multimedia data (particularly for IPTV) using a network coding transmission method (especially on a wireless network).

The object of the present invention is to solve all the problems of the prior art described above.

In addition, the present invention classifies information (e.g., content) according to priority (e.g., user request), and classifies the classified information according to the priority and information that is not network coded (network coding). It is another object to transmit as Network Coding) information.

In addition, since the present invention can receive and use only necessary data immediately, it is another object to enable efficient data transmission since it is not necessary to wait until the transmission of all data is completed.

Representative configuration of the present invention for achieving the above object is as follows.

According to an aspect of the present invention, there is provided a method for transmitting data based on network coding, comprising: (a) classifying information into a plurality of groups based on a priority according to a request of a user terminal device; Transmitting, to the user terminal device, a group having a higher priority than a predetermined threshold among the groups of (c), and (c) network coding a group having a lower priority than the predetermined threshold among the plurality of groups. Provided is a method comprising transmitting to the user terminal device.

According to another aspect of the present invention, there is provided a system for transmitting data based on network coding, comprising: an information classifying unit for classifying information into a plurality of groups based on a priority according to a request of a user terminal device, and a plurality of groups; Transmitting the group having a higher priority than the predetermined threshold to the user terminal without network coding, and then network coding the group having a lower priority than the predetermined threshold among the plurality of groups to the user terminal. A system including a network coding unit is provided.

In addition, there is provided another method, system, and computer readable recording medium for recording a computer program for carrying out the method for implementing the present invention.

According to the present invention, information (eg, content) may be classified according to priority (eg, user request) to provide only necessary information without encoding through network coding.

In addition, according to the present invention, by selectively performing network coding on the information having a lower priority among the classified information, it is possible to minimize the transmission error and enjoy the advantages of network coding that can improve the transmission amount. This can improve the disadvantages of packet delay and data synchronization.

In addition, according to the present invention, it is possible to improve the transmission efficiency on the entire network (particularly, the wireless network).

DETAILED DESCRIPTION The following detailed description of the invention refers to the accompanying drawings that show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood that the various embodiments of the present invention are different but need not be mutually exclusive. For example, certain features, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the invention in connection with an embodiment. It is also to be understood that the position or arrangement of the individual components within each disclosed embodiment may be varied without departing from the spirit and scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled. Like reference numerals in the drawings refer to the same or similar functions throughout the several aspects.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

[Preferred Embodiments of the Invention]

Configuration of the entire system

2 is a diagram illustrating a schematic configuration of a system for classifying and providing information based on network coding according to an embodiment of the present invention.

2, the entire system according to an embodiment of the present invention may include a communication network 100, a main server 200, an information providing system 300, and a user terminal device 400.

First, the communication network 100 according to an embodiment of the present invention may be configured regardless of communication modes such as wired and wireless, and may include a local area network (LAN) and a metropolitan area network (MAN). , Wide Area Network (WAN), Fiber To The Home, Fiber To The Premises (FTTH), and Wireless LAN (Wireless LAN). Preferably, the communication network 100 according to the present invention may be a known World Wide Web (WWW).

Next, the main server 200 according to an embodiment of the present invention may be a device that can provide information (for example, content and related information) to the user terminal device 400. For example, it may be various web servers, and in particular, may be an operation server of IPTV. The main server 200 may provide various information to the user terminal device 400 to the user terminal device 400 through the information providing system 300.

Here, content is a term that collectively refers to digital information accessible through the communication network 100 or its contents, and is a concept of collectively referring to digital information including letters, codes, sounds, sounds, images, and images. For example, data, such as text, an image, a video, audio, a link (for example, a web link), or a combination thereof may be included. In addition, the information related to the content may include advertisement information related to the content as well as content details such as the title, channel number and broadcasting time, and the subtitle of the content, but is not limited thereto.

Next, the information providing system 300 according to an embodiment of the present invention classifies the information provided from the main server 200 according to the priority of the information (for example, a user request), and the plurality of packets A function of dividing into the transmission can be performed.

In addition, the information providing system 300 may classify the packet group into information that is not network coded and network coded information according to priority, and transmit the packet group. Let's find out in detail through the detailed description.

Finally, the user terminal device 400 according to an embodiment of the present invention includes a function for allowing a user to communicate with another device (information providing system 300) by at least one of a wired communication method and a wireless communication method. It may be a digital device. Specifically, a user terminal device according to the present invention may be any digital device having a computing capability by mounting a microprocessor such as a desktop computer, a notebook computer, a workstation, a PDA, a web pad, a mobile phone, an IPTV receiver, or the like. And may be adopted as 400. In particular, the user terminal device 400 may further include a web browser (not shown) program so that a user may receive information from the information providing system 300.

Configuration of Information Providing System 300

Hereinafter, the internal configuration of the information providing system 300 performing important functions for the implementation of the present invention and the function of each component will be described.

3 is a diagram illustrating in detail the internal configuration of the information providing system 300 according to an embodiment of the present invention.

Referring to FIG. 3, the information providing system 300 according to an embodiment of the present invention may include an information classifying unit 310, a packet generating unit 320, a network coding unit 330, a database 340, and a communication unit 350. ) And the control unit 360.

According to an embodiment of the present invention, at least some of the information classifying unit 310, the packet generating unit 320, the network coding unit 330, the database 340, the communication unit 350, and the control unit 360 are selected. Program modules communicating with the main server 200 and / or the user terminal device 400. Such program modules are described in the form of an operating system, an application module, and other program modules, in which the main server 200 and the information providing system 300 are separated in the present invention. It will be apparent that the provision system 300 may be included. In addition, the information providing system 300 may be physically stored on various known storage devices. On the other hand, such program modules include, but are not limited to, routines, subroutines, programs, objects, components, data structures, etc. that perform particular tasks or execute particular abstract data types, described below, in accordance with the present invention.

First, the information classifying unit 310 according to an embodiment of the present invention may perform a function of classifying information provided from the main server 200 into a plurality of groups based on priority.

For example, information corresponding to the information requested by the user terminal device 400 may have a higher priority than other information. In this manner, the information classifying unit 310 may classify the first information group having a higher priority and the second information group having a lower priority than the first information group.

Next, the packet generator 320 according to an embodiment of the present invention may perform a function of dividing the classified information into packets so as to efficiently transmit the classified information through the communication network 100.

For example, as described above, the classified first information group and the second information group may be divided into a total of N packets. Among them, the first group of higher information is divided into L packets to P. _L first packet groups consisting of L may be formed. In addition, the second group of information having a lower priority may be divided into _NLs to form a second packet group including P _{N −L} . Where N and L are natural numbers and N> L.

Next, the network coding unit 330 according to an embodiment of the present invention does not perform network coding on L packets belonging to the first packet group, which is a packet group having a higher priority, from the generated packet group without performing network coding. And transmits to the user terminal device 400 by performing network coding only on the NL packets belonging to the second packet group which is a packet group having a lower priority than that.

In this case, the second packet group may be composed of CP ₁ , CP ₂ , or CP _{N − L} by network coding. More specifically, the second packet group may satisfy Equation 1 below.

[Equation 1]

Here, α _i is a coefficient of the encoding vector and may be used when decoding is performed in the user terminal device 400.

As a result, the network coding scheme according to the present invention sequentially transmits L packets (P ₁ to PL) and NL network coded packets (CP ₁ to CP _{N -L} ) that are not network coded. Instead of having to wait for all packets to be received at 400, it is possible to first receive only the necessary uncoded packets first to obtain the desired information. Subsequently, since the remaining packets are encoded and transmitted by network coding, they can be obtained by performing a decoding process after receiving all of them.

Therefore, it is possible to reduce the transmission error, improve the throughput and the transmission speed, and at the same time improve the disadvantages sensitive to packet delay and data synchronization, thereby improving the transmission efficiency on the entire network (especially the wireless network). Can be improved.

Next, the database 340 according to an embodiment of the present invention may store information provided from the main server 200 (information related to content and content), priority information requested from the user terminal device 400, and the like. In addition, information classified according to priority and network coding information may be further stored.

Meanwhile, although the database 340 is illustrated as being included in the information providing system 300 in FIG. 3, the database 340 may be connected to the information providing system 300 according to the needs of those skilled in the art for implementing the present invention. It may be configured separately. On the other hand, according to the present invention, the database 340 is a concept including a computer-readable recording medium, and refers to not only a narrow database but also a database in a broad sense including a data system based on a file system. Even a simple set of logs can be included in the database 340 according to the present invention if it can retrieve the data by searching it.

Next, the communication unit 350 according to an embodiment of the present invention may perform a function of allowing the information providing system 300 to communicate with an external device such as the main server 200 and the user terminal device 400. have.

Finally, the control unit 360 according to an embodiment of the present invention flows data between the information classifying unit 310, the packet generating unit 320, the network coding unit 330, the database 340, the communication unit 350. It performs the function of controlling. That is, the control unit 360 according to the present invention controls the flow of data from the outside or between each component of the information providing system 300, whereby the information classifying unit 310, packet generation unit 320, network coding unit The control unit 330, the database 340, and the communication unit 350 each perform a unique function.

Embodiments according to the present invention may be implemented in the form of program instructions that may be executed by various computer components, and may be recorded in a computer-readable recording medium. The computer-readable recording medium may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on the computer-readable recording medium may be those specially designed and configured for the present invention, or may be known and available to those skilled in the computer software arts. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tape, optical recording media such as CD-ROMs, DVDs, and magneto-optical media such as floptical disks. media), and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine code generated by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like. The hardware device may be configured to operate as one or more software modules to perform the process according to the invention, and vice versa.

Although the present invention has been described by specific embodiments such as specific components and the limited embodiments and drawings, it is provided only to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments, Those skilled in the art can make various modifications and variations from this description. Therefore, the spirit of the present invention should not be construed as being limited to the above-described embodiments, and all of the equivalents or equivalents of the claims, as well as the following claims, I will say.

1 is a block diagram showing a transmission method of a general network coding system.

2 is a diagram illustrating a schematic configuration of a system for classifying and providing information based on network coding according to an embodiment of the present invention.

3 is a diagram illustrating in detail the internal configuration of the information providing system according to an embodiment of the present invention.

<Brief description of the major reference numerals>

100: network

200: main server

300: informational system

310: information classification unit

320: packet generation unit

330: network coating

340: database

350: communication unit

360: control unit

400: user terminal device

Claims (9)

A method of transmitting data based on network coding, (a) classifying the information into a plurality of groups based on the priority according to the request of the user terminal device; (b) transmitting a group of the plurality of groups whose priority is higher than a predetermined threshold to the user terminal device without network coding, and (c) network coding a group having a priority lower than the predetermined threshold among the plurality of groups and transmitting the same to the user terminal device How to include. The method of claim 1, In the step (a), And wherein the plurality of groups are each divided into a plurality of data packets. The method of claim 1, In the step (a), The plurality of groups may be composed of a first group having a high priority and a second group having a low priority, wherein the preset threshold is present between the priority of the first group and the priority of the second group. How to feature. The method of claim 3, and (d) information contained in the data packet included in the second group received by the user terminal device is restored by performing decoding. A computer-readable recording medium for recording a computer program for executing the method according to any one of claims 1 to 4. A system for transmitting data based on network coding, An information classification unit classifying the information into a plurality of groups based on the priority according to the request of the user terminal device, and After the group of the plurality of groups whose priority is higher than the predetermined threshold is transmitted to the user terminal device without network coding, the group of the plurality of groups whose priority is lower than the predetermined threshold is network coded to allow the user. Network coding unit to transmit to the terminal device System comprising a. The method of claim 6, And a packet generator for dividing the plurality of groups into a plurality of packets, respectively. The method of claim 6, The plurality of groups may be composed of a first group having a high priority and a second group having a low priority, wherein the predetermined threshold is present between the priority of the first group and the priority of the second group. System characterized. The method of claim 8, And the user terminal device restores the information included in the data packet included in the received second group by decoding.

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