KR100567328B1 - The HDTV media gateway system using layered multicasting and the method thereof - Google Patents

Abstract

Disclosed are a media gateway system and a method of operating the same, which enable HDTV services of various image quality from one service source. The HDTV media gateway system and a method of operating the same according to the present invention include a service class changing step and a procedure and an apparatus for selecting a performing node, which include an available band prediction function at a reception side and adjustment of a video transmission rate accordingly. As described above, according to the present invention, the video service according to the user's prior service contract can be watched without interruption of service even when the traffic is congested within the available band of the receiver, and a subset of the same video layer for the live video requested by the client By discovering neighboring nodes in service and receiving the necessary video from them, it can eliminate unnecessary time to the source, improve service performance with effective multicasting transmission, and reduce the additional load of the main gateway processor requiring high speed.

Media Gateway, Multicast, Transcoding

Description

HDTV media gateway system using layered multicasting and the method

BRIEF DESCRIPTION OF THE DRAWINGS In order to better understand the drawings cited in the detailed description of the invention, a brief description of each drawing is provided.

1 is a block diagram of a conventional High Definition Television (HDTV) service network in use.

2 is a block diagram illustrating an HDTV media gateway system according to an exemplary embodiment.

3 is a flowchart illustrating a method of operating an HDTV media gateway system according to another exemplary embodiment of the present invention.

TECHNICAL FIELD The present invention relates to a video streaming service, and more particularly, to a media gateway, a node, a transmission / reception apparatus, and a method for performing a media gateway for enabling HDTV services of various image quality from one service source and related networks.

To provide High Definition TV (HDTV) streaming over the Internet, which is different from the existing streaming capacity, data is transferred at 19.2 Mbps (Mega bit per second) using Moving Picture Experts Group 2 (MPEG2) video compression technology. A technique for transmitting it was made.

However, since there is no special network currently capable of providing 19.2 Mbps of streaming, the original video of 19.2 Mbps can be adapted to the current network by using a transcoding technology that uses one source to service several different qualities. It offers various services from 384Kbps to 19.2Mbps. At this time, in order to efficiently use the bandwidth, when transmitting, transcoding of the video signal is transcoded using a layer compression method and reassembled by the receiving client.

1 is a block diagram of a conventional High Definition Television (HDTV) service network in use.

Referring to FIG. 1, the HDTV service network includes an HDTV camera 100, an MPEG2 encoder 110, an HDTV streaming server 120, an HDTV media gateway 130, an internet network 140, and a plurality of clients 150 and 160. It is composed of

The output of the HDTV camera 100 has a DVB / ASI interface as a live broadcast image of 1.485 Gbps, and is processed as an MPEG2 image of 19.2 Mbps while passing through the MPEG2 encoder 110. Unlike the HDTV camera 100, the HDTV streaming server 120 is responsible for delivering a stored stream source.

The HDTV media gateway 130 receives the output stream of the MPEG2 encoder 110 and transmits it to the Internet network 140 through a predetermined data processing procedure or processes the requirements from the clients 150 and 160. .

The internet network 140 includes a plurality of routers (not shown) to connect the HDTV media gateway 130 and the plurality of clients 150 and 160.

As described above with reference to FIG. 1, since the present invention uses a unicast technology that transmits a low-quality stream source on a one-to-one basis over a network as compared to an HDTV service, Today's networks are not suitable for applying new technologies that offer large amounts of streaming in terms of bandwidth and accepting subscribers.

To overcome this, IP multicast (Internet Protocol) is a technology that does not use unicast between source and user, processes as one stream until it arrives to access router, and finally broadcasts. Multicast) technology is used, but due to the nature of large-capacity media, it is difficult to expect a smooth service only by IP multicasting at the end.

In addition, IP multicast increases the amount of traffic in the network because multicast is always performed to the users of the multicast group, and network traffic changes because users in the same group are served at the same speed regardless of network speed. Can not respond accordingly. First of all, the reliability of the transport protocol of multicasting is a problem to be solved especially in the case of non-interactive streaming such as live broadcasting.

Even the Forward Error Control (FEC) method has a problem to be handled, such as overhead due to retransmission, and it is difficult to maintain performance when there are a large number of live broadcast receivers in order to centrally manage the receiver side.

The first technical problem to be achieved by the present invention is to provide a HDTV media gateway system capable of transmitting high-capacity streaming data of HDTV according to the speed of the network being used and processing the streaming data appropriately even when traffic is congested.

A second technical problem to be achieved by the present invention is to provide a method for operating the HDTV media gateway system.

The HDTV media gateway system according to the present invention for achieving the first technical problem comprises a transcoding module, a switch module, a streaming protocol processing module, a streaming traffic control module and a database.

The transcoding module is a plurality of transcoding engines that receive signals converted from a HDTV stream into a 19.2 Mbps MPEG-2 video stream through MPEG-2 encoding, and convert the received signals into data streams having different transmission rates. Two transcoding boards.

The switch module, when a service request from the client comes in, transmits it to a predetermined streaming protocol processing module and performs multicast by connecting the output stream of the transcoding module to the client.

The streaming protocol processing module analyzes the request message using Real Time Streaming Protocol (RTSP) information about a session requested by clients, and uses the information analyzed by the client's viewing request message. Update the session information of the predetermined database, and transmit the corresponding transcoding request according to the analyzed information to the predetermined streaming traffic control module.

The streaming traffic control module is responsible for starting and initializing the system, and requests transcoding with the node address, service level, and transcoding layer information of the client to the transcoding module, and the converted request video layer is the switch module. And control the system to be transmitted to clients via a path of the internet network.

The database includes route pinning information by label switching in a network collected by the streaming protocol processing module.

The streaming traffic control module generates a BtB packet pair (Back-to-Back Packet Pair) for each layer multicast group every second, and reflects the result of monitoring the link band of the client based on this, thereby congesting traffic. It performs the function of requiring the transcoding module to have a streaming rate so that precautionary measures can be taken.

The plurality of transcoding boards are designed to generate video streams that receive streams of the same rate but differ in transmission rates from 384 Kbps to 19.2 Mbps.

HDTV media gateway system operating method according to the present invention for achieving the second technical problem, a media gateway system including a transcoding module and switching module, streaming traffic control module and streaming protocol processing module for HDTV high-definition streaming in,

It monitors network, measures QoS, adjusts BtB packet generation and layer timer for client's service request, and adjusts data transmission rate according to network traffic situation to prevent congestion in network. Network monitoring and QoS processing to provide video services according to the service class considering and controlling the available bandwidth of each client and processing the video stream required by the client. And a client request processing step of changing a route or driving a layer timer according to the determination result in the step of providing the service as a service to the corresponding client.

DETAILED DESCRIPTION In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings that illustrate preferred embodiments of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals in the drawings denote like elements.

2 is a block diagram illustrating an HDTV media gateway system according to an exemplary embodiment.

Referring to FIG. 2, the HDTV media gateway system 200 includes a transcoding module 210, a switch module 220, a streaming traffic control module 240, and a streaming protocol processing module 230. The database 250 can be used suitably according to a use.

The transcoding module 210 receives a signal in which the HDTV stream is converted into a 19.2 Mbps MPEG-2 video stream through MPEG-2 encoding, and converts the received signal into a data stream having a different transmission rate. A plurality of transcoding boards 211 to 213 are provided. Each transcoding board 211 through 213 has a function of receiving a stream of the same speed but generating a video stream having a different transmission rate from 384 Kbps to 19.2 Mbps.

The switch module 220 performs a multicast. When the service request of the client is received, the switch module 220 transmits it to the streaming protocol processing module 230 and outputs an output stream of the transcoding boards 211 to 213.

The streaming protocol processing module 230 includes a corresponding protocol stack layer (not shown), and analyzes the request message in the stack layer using RTSP information about a session requested by clients. The information analyzed by the client's viewing request message is used to update the session information of the database 250 with route pinning information by label switching in the network collected by the streaming protocol processing module 230. The streaming protocol processing module 230 transmits the corresponding transcoding request according to the analyzed information to the streaming traffic control module 240.

The streaming traffic control module 240 requests the transcoding to the transcoding module 210 along with the client's node address, service level, and transcoding layer information. The converted request video layer is transmitted to clients (not shown) through the switch module 220 and the path of the Internet network. In particular, it is responsible for the startup and initialization of the HDTV media gateway system 200.

In addition, the streaming traffic control module 240 generates a BtB packet pair (Back-to-Back Packet Pair) for each layer multicast group every second, and reflects the result of monitoring the link band of the client based on the traffic. Has a function of appropriately requesting the transcoding boards 211 to 213 a streaming rate to take measures to prevent congestion.

3 is a flowchart illustrating a method of operating an HDTV media gateway system according to another exemplary embodiment of the present invention.

Referring to FIG. 3, a method of operating the HDTV media gateway system includes a network monitoring and QoS processing step 320 and a client request processing step 340, and a transcoding module and switching for HDTV high definition streaming. It is assumed that the media gateway system includes a module, a streaming traffic control module, and a streaming protocol processing module.

The network monitoring and QoS processing step 320 monitors the network, measures the QoS, adjusts the BtB packet generation and layer timer for the client's service request, and adjusts the data transmission rate according to the network traffic. It adjusts the flow of the output stream to prevent congestion in the network, and predicts the available bandwidth of each client to provide a video service suitable for the service class considered.

To this end, the step 320 of processing the network monitoring and QoS,

Monitoring (321) a network and measuring a quality of service (QoS); generating a BtB packet pair having a plurality of classes, and transmitting the generated BtB packet pair and each class number to a client (323); Calculating a usable band by receiving a packet pair and a class number (325), determining whether there is a band resource using the calculated available band, and if the band resource is found, use the value of the current layer timer as it is. Outputting a first control signal C1 instructing to drive the layer timer 327, and if it is determined that there is no band resource, adjusting the value of the layer timer and causing the layer timer to be driven under the adjusted condition. A layer timer adjustment request step 329 for outputting two control signals C2 is provided.

In the client request processing step 340, the video stream requested by the client is changed to a route or a layer timer is driven according to the determination result of the network monitoring and QoS processing step 320 to provide the client with the service. to provide.

To this end, the client service request processing step,

A request / accept processing step 343 requesting a transcoding layer having a rate corresponding to session information including service information requested by the client 341, to perform multicasting on the data coded with the rate. A node assigning step 345 for assigning a node, a layer timer driving step 347 for driving the layer timer according to a first control signal C1 and a second control signal C2 with respect to the assigned node, and a client. Video streaming processing step 351 to suspend the service in response to a request 349 from the video stream or to process the video stream according to the layer timer.

The node assignment step 345 records, in order of arrival, at least two or more nodes arriving at a predetermined timer in the same layer with the information of the streaming video layer received from each node that can configure the requested class of service. It is preferable to allocate a node so as to receive and request video from the corresponding node of the node, and to receive video of the corresponding layer from the node of the next rank if service synchronization is difficult from the node of the previous rank.

The network monitoring and QoS processing step 320 further includes a route change request step 331 for outputting a signal C3 requesting to change the route of data traffic by route pinning and determining the route pinning. The request / acceptance processing step 343 further includes a step (included in 343) of accepting the service request by reflecting the data modifications to the route change request signal C3, which is information by label switching. The detour route based on the pinning data can be calculated and confirmed.

Here, the step 327 of determining the presence or absence of the band resource, compares the received available band and the cumulative band layer currently in service, and determines that there is no band resource when the available band value is small within the service maximum class range of the subscriber profile. The class number is lowered, and in the opposite case, it is determined that there is a band resource, and the class number is increased.

The layer timer adjustment request step 329 includes a join timer and a search timer used by each layer, and joins to the upper part when the join timer of the corresponding layer expires when receiving live broadcast, and joins to the lower part when the congestion of the user is found thereafter. The join timer is increased by a predetermined increase factor, and when the detection timer expires, the join timer is decreased by a predetermined decrease factor. When the congestion of the uppermost layer exceeds a predetermined threshold, the layer of the client in the node The ranks are joined in a lower order, and when resolved, joins are performed sequentially in the upper order according to each client service class.

The client service request processing step 340 collects operation data and charging information obtained during operation of the layer timer adjusted as a result of node allocation and available band calculation, and transmits the collected operation data and charging information to the network monitoring and QoS processing step 320 (353). It is further provided.

The HDTV media gateway system operating method 300 according to the present invention described above is outlined below.

Initialization step 310 performs the startup and initialization of the HDTV media gateway system 200, the streaming traffic control module 240 is responsible for this. For example, a database for initializing system operating parameters, resource information, quality of service (QoS) parameters, multi-protocol label switching (MPLS) related traffic engineering parameters, label information, and network topology information is initialized.

When the initialization step 310 is completed, the network monitoring and QoS measurement process for link congestion is driven by the streaming traffic control module 240 to reflect the protocol processing result of the streaming protocol processing module 230 in the system operation.

The client opens a socket of a user terminal to watch HDTV live broadcast and transmits session information to the streaming protocol processing module 230 using a real time streaming protocol to the HDTV media gateway which is a source system (341).

The streaming protocol processing module 240 receives the request for the requested transcoding layer to the streaming traffic control module 230 (343).

In the request / acceptance processing step 343, the service request is reflected by applying data modifications to the route pinning and route change message processing (root pinning and route changing step 331) according to the root pinning and route change determination of the streaming traffic control module 230. Accept and process. The streaming traffic control module 240 then generates a transcoding layer rate on the transcoding boards 211 to 213 and opens a Real Time Protocol (RTP) session to open the UDP port p (RTCP) with a terminal IP address. Protocol) assigns a node to perform layer multicasting on the p + 1 port (345) and transmits the requested stream. At this time, the address, data port, and control port for layer video streaming are sequentially numbered sequentially.

In the network monitoring and QoS measurement step 321, the packet pair generated by the process of generating and driving the BtB packet pair is transmitted (323), and the received client calculates an available band (325). It is determined whether it is possible (327).

If the bandwidth resource for the request layer is not available, the layer timer is adjusted (329). If there is no problem with the bandwidth resources or by the driven (347) layer timer value performed after opening the layer timer adjustment, the live video service for each client class of service profile is streamed through the layer through the assigned node 345. Processed and sent (351).

If the client stops the service 349 while the live video service is being streamed and transmitted 351 through the corresponding layer, the streaming service is stopped.

Operational data according to the layer timer operation 347 and billing information for each layer use per service class are collected, transferred to the network monitoring and QoS measurement step 320 (353), and used for network operation management and charge.

The available band in the available band calculation step 325 is obtained by the following method. The media gateway system 200, together with the system start-up 310, generates N (N is real) streaming video layers (grades 0-N) from one low speed to 19.2M per live broadcast station per transcoding device. . N is assumed to be 4 below.

The same number of BtB packet pairs as the class number (if N is greater than 2) are transmitted to the client every generation period. The client receives this to calculate the available band and compares the result of the calculation with the cumulative band layer cumulative value in service, and drops it to the lower level if the available band is small within the maximum service class of the subscriber profile. In the opposite case, change to a higher level. The available band B is represented by Equation 1.

Where t (n) is the arrival time for the nth input packet of the packet pair. This traffic information is collected to the media gateway system through the RTCP message between nodes in order to estimate the network condition.

The client uses a join-timer and a detection-timer as a timer used by each layer as the layer changes.

If the join timer of the corresponding layer expires during live broadcast reception, join to the upper layer, and if congestion is detected, join to the lower layer and increase the join timer by an increase factor.

If the detection timer expires, the join timer is decremented by a decrement factor. At this time, layer change control between clients in the node is performed based on the initialization value of the media gateway system according to the policy of fairness and differential consideration of the clients in the node. When the congestion of the uppermost layer exceeds the threshold, the client's layer grades are joined to the lower level, and when it is resolved, the joining is performed sequentially according to each client service grade. Here, the join timer ratio for each layer applied to each layer is managed by the streaming traffic control module 240 of the media gateway system.

라 하면, 각 등급별 조인 타이머는 수학식 2를 만족한다. The join timer for layer k

In this case, the join timer for each level satisfies Equation 2.

및 n은 클라이언트를 수용하는 종단 링크 측 타이머 보정계수 및 총 수용 클라이언트의 수, b 는 멀티캐스팅 분기 노드의 타이머 보정계수이다. 보정계수는 망운용 상황에 따른 미디어 게이트웨이 시스템의 트래픽 제어 모듈에 의해 할당된다. 이 값이 멀티캐스팅 분기 노드들에게 전송되고 노드 내 각 클라이언트 단말기는 이 값을 세팅하여 조인 타이머를 운용한다. Where L is a service grade (0-3).

And n is the end link-side timer correction coefficient that accommodates the client and the total number of receiving clients, b is the timer correction coefficient of the multicasting branch node. The correction factor is assigned by the traffic control module of the media gateway system according to the network operation situation. This value is sent to the multicasting branch nodes and each client terminal in the node sets this value to run the join timer.

For a new subscription or a modified class of service, the client-side access router sends a broadcast message upstream requesting the video service of the required layer. In this case, the message includes a station ID, a video title ID, and a service class ID. If the live stream video corresponding to the upstream node is in service, the client notifies the client of the layer information of the video. The client sends the received information of the streaming video layer from each node that can configure the requested class of service to the first and the second (if possible) received within a certain timer for the same layer, ie two for each access node. Arrives the arrivals of nodes in the order of arrival and receives video requests from the nodes. If service synchronization is difficult from the first receiving node, video of the corresponding layer is received at the second node.

As described above, the optimum embodiment has been disclosed in the drawings and the specification. Although specific terms have been used herein, they are used only for the purpose of describing the present invention and are not intended to limit the scope of the invention as defined in the claims or the claims. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described above, the present invention can be applied to switching modules and network operations as well as performance degradation for the transcoding module without using the IP multicast function in a media gateway server having a structure of several transcoding modules and a switch module. Performance degradation due to bottleneck link generation due to traffic congestion can be avoided. In addition, it is possible to automatically provide optimal video quality to end-to-end heterogeneous clients according to network demands as well as traffic congestion and resolution. This reduces network bandwidth waste due to existing unicast and can deliver multiple rates as a reliable source gateway for one source stream.

Claims (13)

A plurality of transcoding boards are transcoding engines that receive signals converted from a HDTV stream through a MPEG-2 encoding into a 19.2 Mbps MPEG-2 video stream and convert the received signals into data streams having different data rates. A transcoding module; A switch module for transmitting a service request of a client to a predetermined streaming protocol processing module and performing multicast by connecting the output stream of the transcoding module to the client; The request message is analyzed using real time streaming protocol information on a session requested by clients, and the session information of a predetermined database is updated using the information analyzed by the client's viewing request message. A streaming protocol processing module for transmitting a corresponding transcoding request according to the analyzed information to a predetermined streaming traffic control module; It is responsible for starting up and initializing the system, and requests transcoding with the node address, service level, and transcoding layer information of the client to the transcoding module, and converts the requested video layer through the path of the switch module and the Internet network. A streaming traffic control module for controlling the system to be transmitted to clients; And And a database having route pinning information by label switching in a network collected by the streaming protocol processing module. The method of claim 1, wherein the streaming traffic control module, To create a BtB packet pair (Back-to-Back Packet Pair) per layer multicast group every second and reflect the results of client's link band monitoring based on this, and take measures to prevent traffic congestion. And a function for requesting said transcoding module for a streaming rate. The method of claim 1, wherein the plurality of transcoding boards, HDTV media gateway system for receiving streams of the same speed but generating different video streams with different transfer rates from 384 Kbps to 19.2 Mbps. In a media gateway system including a transcoding module and a switching module, a streaming traffic control module, and a streaming protocol processing module for HDTV high definition streaming, It monitors network, measures QoS, adjusts BtB packet generation and layer timer for client's service request, and adjusts data transmission rate according to network traffic. Processing network monitoring and QoS to control the flow and to provide a video service for a service class considering a changing available band of each client; And And a client request processing step of providing a video stream requested by a client as a service to a corresponding client by changing a route or driving a layer timer according to the determination result of the network monitoring and QoS processing. HDTV media gateway system operation method. The method of claim 4, wherein the network monitoring and QoS processing step, Monitoring the network and measuring a quality of service (QoS); Generating a BtB packet pair having a plurality of classes, and transmitting the generated BtB packet pairs and respective class numbers to the client; Calculating an available band by receiving the packet pair and class number; Determining whether there is a band resource by using the calculated available band, and if it is determined that there is the band resource, outputting a first control signal instructing to drive the layer timer using the current layer timer value as it is. ; And And a layer timer adjusting step of outputting a second control signal for driving the layer timer under adjusted conditions and adjusted conditions of the layer timer when it is determined that there is no band resource. The method of claim 5, The client service request processing step is A request / acceptance processing step of requesting a transcoding layer having a rate corresponding to session information including service information requested by a client; A node assignment step of assigning a node to perform multicasting on the rate coded data stream; A layer timer driving step of driving the layer timer with respect to the assigned node according to the first control signal and the second control signal; And a video streaming processing step of stopping a service according to a request from a client or processing a video stream according to the layer timer. The method of claim 6, wherein the node assignment step, In the same layer, at least two or more nodes arriving within a predetermined timer are recorded in the order of arrival, and the video from the corresponding node of the higher priority is requested. The information of the streaming video layer received from each node that can configure the requested class of service is recorded. And a node is allocated to receive a video of a corresponding layer from a node having a next rank when service synchronization is difficult from the node having a previous rank. The network monitoring and QoS measurement step of claim 6, And a route change request step of outputting a signal requesting to change the data traffic route by route pinning and determining the route pinning. The request / accept processing step, Further comprising the step of accepting the service request by reflecting the data modification to the route change request signal, A method for operating an HDTV media gateway system, comprising: calculating and confirming a bypass route based on route pinning data which is information by label switching. The method of claim 5, wherein the available band (B),

Satisfying t (n) represents the arrival time for the nth input packet of the packet pair. The method of claim 5, wherein the determining of the presence or absence of the band resource, If the available band value is small within the maximum class range of the subscriber's profile, it is determined that there is no band resource, and the class number is lowered. HDTV media gateway system operating method, characterized in that to increase the rating number to the higher. The method of claim 5, wherein adjusting the layer timer comprises: Each layer has a join timer and a search timer that are used.When a live broadcast is received, the join timer of the corresponding layer expires, and if the congestion of the user is detected afterwards, the join joins to the lower level and the join timer is increased by a predetermined increment factor. If the detection timer expires, the join timer is reduced by a predetermined reduction factor. If the congestion of the top layer exceeds a predetermined threshold value, the layer grades of the clients in the nodes are joined to the lower level, and when the resolution is resolved, the joining is performed sequentially sequentially according to each client service class. How to operate. The method of claim 11, wherein the grade join timer,

Satisfying

Is the join timer in layer k , L is the class of service,

And n is an end link side timer correction coefficient for accommodating the client and the total number of accommodating clients, b is a timer correction coefficient for the multicasting branch node. The method of claim 6, wherein the client service request processing step, And collecting the operational data and the charging information acquired during the operation of the layer timer adjusted as a result of the node allocation and the available bandwidth, and forwarding the collected data to the network monitoring and QoS processing step.

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