WO2008110122A1

WO2008110122A1 - A method, system and buffer entity for switching network tv channels

Info

Publication number: WO2008110122A1
Application number: PCT/CN2008/070493
Authority: WO
Inventors: Xiangyang Wu; Jun Yan; Wenming Zhu
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2007-03-15
Filing date: 2008-03-13
Publication date: 2008-09-18
Also published as: CN101267538A; CN101267538B

Abstract

A method, system and buffer entity for switching network TV channels. It relates to the field of the network TV technology, and is used for reducing delay of switching network TV channels. Wherein, the method is that: a buffer entity buffers generated switching media flow, and sends the switching media flow of a target channel to a media receiver after receiving a switching request; after the switching request is accepted, a media provider sends normal media flow of the target channel to the media receiver, so that the delay during the network transmission and due to performing the switching request by a signaling-side is reduced. Further more, the invention can introduce an authentication process, and the delay caused by signaling alternation during the authentication process is reduced. And it can be used for switching IPTV channels quickly when they are transmitted not only in a multicast mode, but also in unicast mode.

Description

Method and system for switching network television channels and cache entity

The present invention relates to network television (IPTV) service technologies, and in particular, to a method and system for switching IPTV channels and a cache entity.

Background technique

With the rapid development of Internet applications and the emergence of IP technologies, IPTV services have emerged and developed rapidly. This service introduces traditional TV services into IP networks and provides a brief description of technologies related to IPTV services.

Session Initiation Protocol (SIP) is one of the multimedia communication system framework protocols developed by the Internet Engineering Task Force (IETF). It is an application layer protocol for establishing, changing or ending multimedia sessions, and real-time transport protocol (RTP) / real-time transport. Protocols such as Control Protocol (RTCP), Session Description Protocol (SDP), Real-Time Streaming Protocol (RTSP), or Domain Name Service (DNS) work together to complete session establishment and media negotiation in IMS.

In order to meet the increasing demand for more and more prominent IP multimedia applications, the 3rd Generation Partnership Project (3GPP) introduced the IP Multimedia Subsystem (IMS) of the all-IP service network architecture based on the packet bearer network, with the goal of personalization. User data, shielding the user access mode and controlling the openness of business capabilities, thus providing a multimedia communication experience. IMS is a subsystem superimposed on the existing packet domain in the WCDMA network added in the 3GPP R5 phase. The packet domain is used as the bearer channel for the upper layer control signaling and media transmission, and SIP is introduced as the service control protocol. Separation of control from bearer control to provide rich multimedia services; The main functional entities in IMS include Call Session Control Entity (CSCF), which controls functions such as user registration and session control, and application servers (AS) that provide various logic control functions. A Home Subscriber Server (HSS) that manages subscriber subscription data and a Media Gateway Control Function Entity (MGCF) / IP Multimedia-Media Gateway (IM-MGW) for implementing circuit-switched network interworking, and the media receiver passes the current local proxy CSCF ( P-CSCF) access to the IMS, session and service trigger control and service control interaction with the AS are performed by the home domain service CSCF (S-CSCF) of other registered places. IP multicast is a technology for sending services by IP address. The sender can use IP multicast to send the same service content to multiple receivers at the same time. Because the same content only needs to send one copy to the specified multicast address, it can be effective. Reduce the load on the traffic sender and transport network. Users can join the service multicast group by using protocols such as Internet Group Management Protocol (IGMP) to obtain multicast content.

Using multicast technology to transport traffic, the sender of the service only needs to send one stream regardless of the number of recipients. The multicast data only generates a single data stream between the transmission points on the transmission path from the sender of the service to the receiver.

Hierarchical video coding technology encodes video streams at different levels, and can output multiple coding layers, consisting of the most important base layer and multiple enhancement layers on it. The base layer and the enhancement layer can be separately transmitted. The base layer can independently decode the base layer video at the receiving end, but the enhancement layer must rely on the base layer and/or the enhancement layer below it to decode and reconstruct the corresponding video. The final video stream is obtained by separately parsing and superimposing the basic layer and the enhancement layer. This technique is used to encode the video stream so that its data rate is relatively small, the transmission delay in the network is also small, and the decoding speed of the terminal is relatively fast.

The Moving Picture Experts Group (MEPG) stream consists of a coded frame (I frame), a predictive coded frame (P frame), and a bidirectionally predictive coded frame (B frame); wherein the I frame contains the most comprehensive information in a static picture. The picture can be decoded by the decoder independently, and its codec is completely determined by itself, without relying on other frames; the P frame depends on the previous I frame to complete the codec; and the B frame depends on the current I frame and the correlation. The P frame can complete the codec. Therefore, the I frame is very important in the MPEG stream. In order to reduce the data rate of the video stream, key I frames can be extracted, a quasi-dynamic video stream can be generated, and even N consecutive M I frames can be extracted. Streamline the video stream size, where M>N.

In traditional TV technology, all channel content is generally sent to the media receiver in a frequency-division manner, such as cable TV (CableTV), which is commonly used. If the media receiver wants to switch channels, it only needs to tune to the corresponding channel. On frequency or frequency band. For IPTV, the limitation of factors such as transmission bandwidth is to transmit the content of part of the media to the media receiver as needed, instead of simultaneously transmitting the content of all channels. At this time, the channel switching involves the signaling of the media receiver and the network. Inter-processes may cause delays in all aspects of the entire handover process, affecting the end user's final experience. Among them, the delays in the whole switching process generally include the following three types:

The access node generates a delay when processing the Internet Multicast Management Protocol/Multicast Listener Discovery Protocol (IGMP/MLD);

The delay generated by the media stream being transmitted from the media server to the access node;

The delay that occurs when the media receiver decodes the media stream and displays it.

At present, there are several solutions to the delay problem of IPTV switching channels:

First, for IPTV real-time TV service, a technical scheme based on Digital Subscriber Loop (DSL) is shown in Figure 1. The solid line in the figure indicates the transmission of the media stream, and the dotted line indicates the signaling transmission. The technology uses IP multicast technology to transmit media streams to media receivers. The media receivers use IGMP/MLD to request access to the channel's multicast address from the access node of the access network to receive the channel program, and use the multicast in the core transport network. The routing technology establishes a multicast forwarding path, and the multicast data packet sent by the media server reaches the access network through the core transmission network and is finally sent to the media receiver. In order to effectively control the media receiver, the access node for the DSL access network, such as a Digital Subscriber Loop Access Multiplexer (DSLAM) or a Broadband Remote Access Server (BRAS), performs control for channel rights; Here, the channel switching request of the media receiver is finally embodied by the media group joining or leaving the multicast group of the playing channel by using the IGMP/MLD protocol. Generally, by checking the permission list configured on the DSLAM or the BRAS, it is determined whether the media recipient is allowed to do this. Secondary channel switching operation. In order to reduce the delay of channel switching, the content of multiple channels is sent to the edge of the access network in advance, and the content is directly sent from the access node of the access network to the media receiver when the media receiver requests the channel content, thereby saving the media stream from The delay time that the media server transmits to the access node of the access network; when no media receiver views the content, the access node of the access network discards the received channel content.

For the unicast mode, when the media receiver performs channel switching, the core transmission network must obtain the content of the target channel from the media server, so the method reduces the delay by transmitting the channel content to the access network in advance. Not suitable for channel switching in unicast mode.

Second, based on the development of Next Generation Network (NGN), the idea of separating control and bearer Deploy the IPTV service. The media receiver performs a service request on the signaling plane, and the network performs operations such as authentication, status recording, and charging on the media receiver, and obtains transmission parameters of the media plane, and then the media receiver requests relevant media resources on the media side. The basic idea is: When the media receiver makes an initial channel request, it negotiates a switching channel between the media receiver and the media server. When the media receiver performs channel switching, the channel is used to deliver and display low resolution or/and quasi-static. Switching the media stream; until the normal handover process ends, the media receiver receives the normal media stream. The structure of the method is shown in Figure 2, in which the upper arrow indicates the low resolution switching media stream and the lower arrow indicates the normal media stream. The switching media channel already exists when the initial request is made by the media receiver, and does not have to wait until the channel is switched. The media receiver simultaneously delivers the switching media stream while the media receiver is watching the program normally, but the media receiver loses the media stream. Discard; When the media receiver switches channels, the media receiver receives the switching media stream.

This method can further reduce the transmission delay. However, when the media server is far away from the user terminal, the core network transmission delay will be longer. In addition, when the authentication process is introduced, the media receiver sends a request to the media. The server must deliver the media stream after the authentication succeeds. Therefore, when the switching request is made on the signaling plane, it will cause a long delay and affect the user experience. Summary of the invention

In view of this, the embodiments of the present invention provide a method for switching network television channels, so as to reduce the delay of switching IPTV channels.

The embodiment of the invention further provides a system for switching network television channels, so as to reduce the delay of switching IPTV channels.

An embodiment of the present invention provides a method for switching a network television channel. The method includes: the cache entity buffers the generated switched media stream, and after receiving the handover request, sends a switching media stream of the target channel to the media receiver; After being accepted, the media provider sends a normal media stream of the target channel to the media recipient.

An embodiment of the present invention provides a system for switching a network television channel, where the system includes: a handover flow generation unit, a cache entity, a media provider, and a media receiver; The switching stream generating unit receives the normal media stream sent by the media provider and generates a switching media stream, and sends the packet to the cache entity;

The buffering entity buffers the switched media stream sent by the switching stream generating unit, and after receiving the switching request sent by the media receiver or the media provider, sends the switching media stream of the target channel to the media receiver; receiving the switching of the media receiver After the request, forwarded to the media provider or not forwarded to the media provider;

The media provider sends a normal media stream to the switching stream generating unit. After the switching request is accepted, the normal media stream of the target channel is sent to the media receiver. After receiving the switching request sent by the media receiver, the packet is forwarded to the cache entity or not forwarded. Give the cache entity;

The media recipient sends a handover request to the media provider or the caching entity, receives the switched media stream from the target channel sent by the caching entity, and receives the normal media stream from the media provider's target channel.

The embodiment of the present invention further provides a cache entity, where the cache entity includes: a cache unit, a transceiver unit, and a determining unit;

a cache unit, configured to cache the switched media stream;

The transceiver unit receives the switching media stream and sends the packet to the buffer unit. After receiving the handover request, the switching media stream in the buffer unit is sent out, and after receiving the handover request of the media receiver, the packet is forwarded to the media provider or not forwarded to the media. provider.

It can be seen from the above technical solution that the setting cache entity caches the switched media stream, and immediately after receiving the handover request, sends the switched media stream to the media receiver, which reduces the delay caused by the network transmission process; During the handover request, the media receiver may first receive the switched media stream of the target channel, thereby reducing the delay caused by the signaling plane performing the handover request. Therefore, the method and system provided by the embodiments of the present invention can reduce the delay in the IPTV channel switching process whether in the unicast mode or the multicast mode.

DRAWINGS

1 is a system structural diagram of a fast switching IPTV channel based on xDSL in the prior art; 2 is a system structure diagram of an NGN-based fast switching IPTV channel in the prior art; FIG. 3 is a system structure diagram of a fast switching IPTV channel according to an embodiment of the present invention; a structure diagram of the cache entity;

FIG. 4.1 is a structural diagram of a system according to Embodiment 1 of the present invention;

Figure 4 is a system structure diagram of a traditional IPTV service according to the first embodiment of the present invention; Figure 4. 3 is a flowchart of a method for providing a traditional IPTV service according to the first embodiment of the present invention; The embodiment of the invention provides a system structure diagram of the second solution;

FIG. 5 is a system structure diagram of an NGN layered design according to an embodiment of the present invention; FIG. 5 is a flowchart of a NGN layered design method according to an embodiment of the present invention; FIG. A system structure diagram of the third solution is provided for the embodiment of the present invention;

Figure 6.2 is a system structure diagram of an IMS network architecture based on the third embodiment of the present invention; and Figure 6.3 is a flowchart of a method for providing an IMS network architecture based on the third embodiment of the present invention. detailed description

In order to make the objects, technical solutions, and advantages of the present invention more apparent, the present invention will be described in detail below with reference to the specific embodiments.

The method provided by the embodiment of the present invention is: the cache entity caches the generated switched media stream, and after receiving the handover request, sends the switched media stream of the target channel to the media receiver; after the handover request is accepted, the media provider receives the media stream from the media. The normal media stream of the target channel is sent.

The process of generating the switched media stream is to modify the normal media stream to be different from the normal media stream in media parameters such as compression ratio, transmission bit rate, resolution, etc., to form a low-resolution and/or quasi-static video frame. Image information is transmitted so that the transmission delay can be reduced. The modification to the normal media stream may be one of the following modes or a combination of any two or more of the following: 1) using layered coding and transmission for the video content, and switching the media stream using only the base layer coding, for reducing The bit rate of the video stream; 2) In the MPEG video coding mechanism, the I frame is extracted from the video stream to form a quasi-dynamic I frame sequence as the content of the switched media stream; 3) only N of the M consecutive I frames are selected Transmission is performed as an I frame sequence, where M>N; 4) image size compression or the like is performed for each I frame. Switching media The specific generation process of the flow is not the focus of the present invention, so it will not be described in detail.

The generation of the switching media stream may be completed by the caching entity, the caching entity receives the normal stream from the media provider, and then forms the switching media stream to directly cache; or may be completed by the media provider, and then the media provider directly sends the generated switching stream. Cache the cached entity; or send the normal media stream to a separate device by the media provider, the independent device modifies the normal media stream to generate a switched media stream, and then sends the cached media stream to the cache entity for caching. The process of switching the media stream is not stopped, so as to ensure the continuity of the switching media stream.

In the implementation of the IPTV service, in consideration of the bandwidth requirement of the media transmission, in order to avoid the congestion of the core transmission network and optimize the media transmission time, the cache entity is set to cache the switched media stream in the method, and after receiving the handover request, The media stream is delivered to the media receiver to reduce the delay of the media stream during transmission.

The cache entity caches the switched media stream, and the dynamic cache mechanism is used. The switched media stream is temporarily saved according to service requirements, and the content of the switched media stream is updated under a certain aging mechanism. The cached media stream can be an application-level media file or a packet-level packaged media data. The cache entity temporarily saves the switched media stream by caching the latest N seconds of content, wherein the setting of N seconds is determined by the specific situation, and the setting of N seconds is related to the time of completing the channel switching.

When receiving the handover request, the cache entity immediately sends the switched media stream of the target channel to the media receiver, and does not stop the buffering process of the new switched media stream during the sending of the switched media stream of the target channel, This ensures that the switching media stream is continuous during the handover process.

The media provider is an entity that provides an IPTV service in the network, and may be an IPTV middleware or a media server. The media receiver may be a user terminal such as a set top box (STB) or a computer (PC). The cache entity is a logical or physical functional entity in the network, and may be a media cache entity (Cache).

When the media receiver switches the channel, the first request is to send a handover request, and the handover request can be directly sent to the cache entity and sent to the media provider. After receiving the handover request, the cache entity performs the switching of the target channel to the media stream, and the media is delivered. When the provider receives the handover request, the handover request is accepted, the media The physical provider sends the normal media stream of the target channel to the media receiver; the media receiver can also send the handover request to the media provider, and the media provider forwards the handover request to the cache entity and delivers the normal media stream of the target channel, and the cache entity After receiving the handover request, the normal media stream of the target channel is delivered. The handover request includes an identifier of the target channel, location information of the media receiver, and the like. When used in the unicast mode, the media provider and the cache entity may send corresponding media streams to the media receiver according to the location information of the media receiver. When used in the multicast mode, the media receiver joins the corresponding multicast when switching channels. The media provider and the cache entity send the corresponding media stream to the multicast group.

Further, after the media provider sends the normal media stream of the target channel, the cache entity stops the switching media stream of the target channel, and the process may be: the media provider notifies the cache entity after delivering the normal media stream of the target channel. Stop the sending of the switching media stream of the target channel; or: after receiving the normal media stream of the target channel, the media receiver notifies the cache entity to stop transmitting the switched media stream of the target channel; or may set a time limit to the timing time limit Afterwards, the cache entity automatically stops the transmission of the switched media stream of the target channel, and the method can be used in combination with the first two methods of stopping the delivery of the switched media stream. The set time limit is generally greater than the time T, where T is the time taken by the media receiver to send the handover request to the media provider to deliver the normal media stream.

Further, the method may include an authentication process, where the media receiver may include the user's authentication request in the handover request when sending the handover request, or may send the media request to the media provider when the cache entity receives the handover request. The authentication request includes the user's authentication information and/or location information.

After receiving the authentication request, the media provider authenticates the media receiver, and the authentication succeeds that the handover request is accepted, and continues to perform the step of the media provider transmitting the normal media stream of the target channel to the media receiver; if the authentication If the media provider fails, the media provider does not send the normal media stream of the target channel to the media receiver, and notifies the cache entity to stop transmitting the switched media stream of the target channel.

In addition, authentication can be done by a separate device, such as an authentication unit. The media receiver may send the handover request to the cache entity, and the cache entity sends the authentication request to the authentication unit for authentication. After the authentication succeeds, the media provider is notified that the handover request is accepted; or , The media receiver sends the handover request to the cache entity, and the cache entity forwards the handover request to the media provider, and the media provider sends the authentication request to the authentication unit for authentication. After the authentication succeeds, the media is notified. The provider switching request is accepted. Alternatively, the media receiver sends a handover request to the cache entity and the authentication unit, and the authentication unit performs authentication. After the authentication succeeds, the media provider is notified that the handover request is accepted.

When the media receiver sends a handover request to the cache entity, it can use IGMP, RTSP, SIP or other related protocols. When forwarding the handover request and/or authentication request between the cache entity and the media provider, RTSP, SIP, H can be used. 248 or other related protocol; Hypertext Link Protocol (HTTP), RTSP, SIP or other related protocols may be used when the media recipient sends a handover request to the media provider.

The cache entity delivers the switched media stream of the target channel to the media receiver, and/or the media provider delivers the switched media stream or the normal media stream to the cache entity, and/or the media provider delivers the target channel to the media receiver For normal media streaming, the RTP/RTCP protocol can be used, and the transmission mode can be unicast or multicast.

The system provided by the embodiment of the present invention is as shown in FIG. 3. The system includes: a handover flow generation unit 301, a cache entity 302, a media provider 303, and a media receiver 304.

The switching stream generating unit 301 is configured to generate a switching media stream from the normal media stream sent by the media provider 303, and send the packet to the cache entity 302.

The switching stream generating unit 301 modifies the received normal media stream to be different from the normal media stream in media parameters such as compression ratio, transmission bit rate, resolution, etc., to form a low-resolution and/or quasi-static video frame. Image information is transmitted so that the transmission delay can be reduced.

The switching stream generating unit 310 may be an independent device, may be disposed in the cache entity 302, or may be disposed in the media provider 303.

The buffering entity 302 caches the switched media stream sent by the switching stream generating unit 301, and after receiving the switching request of the media receiver 304, transmits the switching media stream of the target channel to the media receiver 304. The cache entity 302 temporarily saves the switched media stream by caching the latest N seconds of content, where N seconds is determined by a specific case, and the setting of the N seconds is related to the time of completing the channel switching.

The cache entity 302 can be a Cache.

The media provider 303 sends a normal media stream to the handover stream generating unit; after the handover request is accepted, the media stream of the target channel is sent to the media receiver 304.

The media provider 303 can determine that the handover request is accepted upon receiving the handover request.

The handover request may also be sent by the media receiver 304 to the caching entity 302, and then sent by the caching entity 302 to the media provider 303; or may be sent by the media receiver 304 to the media provider 303, and then the media provider 303 forwards the request to the media provider 303. Cache entity 302.

The media provider 303 may be an IPTV middleware or an entity capable of providing an IPTV service, such as a media server.

The media recipient 304 transmits a handover request; receives a switched media stream from the target channel of the cache entity 302, and receives a normal media stream from the target channel of the media provider 303.

The media provider 303 may also first send the normal media stream of the target channel to the cache entity 302, and the cache entity 302 sends the normal media stream of the target channel to the media receiver 304.

The media recipient 304 can be a user terminal, such as an STB, or PC, capable of receiving and processing IPTV media content. The processing refers to display, recording, or other operations.

Further, after receiving the handover request, the media provider 303 sends a stop notification to the cache entity 302, and the cache entity 302 stops transmitting the switched media stream of the target channel to the media receiver 304 after receiving the stop notification; and/or arrives After the timing period, the switching media stream of the target channel is automatically stopped from being sent to the media receiver 304. The set time limit is generally greater than the time T, where T is the time taken by the media receiver to send a handover request to the media provider to deliver the normal media stream.

After receiving the handover request, the media provider 303 may also first send a handover request acceptance notification to the media receiver 304, and then the media receiver sends a stop notification to the cache entity 302.

Further, the system further includes: an authentication unit 305;

The switching request includes an authentication request; The authentication unit 305, after receiving the authentication request sent by the cache entity 302 or the media provider 303 or the media receiver 304, performs authentication, and after the authentication succeeds, notifying the media provider 303 that the handover request is accepted;

The cache entity 302 is further configured to: after receiving the handover request of the media receiver, send the authentication request to the authentication unit; or

The media receiver 304 is further configured to send the authentication request to the authentication unit directly. Alternatively, the media provider 303 is further configured to send the authentication request to the authentication unit.

The authentication unit 305 can be a standalone device or can be included in the media provider 303. The following describes the structure of the cache entity. As shown in Figure 3.2, the cache entity mainly includes: a cache unit 01, and a transceiver unit 02;

a cache unit 01, configured to cache the switched media stream;

The transceiver unit 02 receives the switched media stream and sends it to the buffer unit 01. After receiving the handover request, the switching media stream in the buffer unit 01 is sent out. After receiving the handover request of the media receiver, the packet is forwarded to the media provider or not. Forward to the media provider.

The buffering entity may further include: a switching stream generating unit 03, configured to modify the normal media stream to form a switching media stream, and send the packet to the transceiver unit 02.

The transceiver unit 02 is further configured to stop sending the switching media stream after the handover request is accepted.

The cache entity further includes a timing unit 04 for setting a timing time limit, and sending a stop notification to the transceiver unit 02 when the timing time expires;

The transceiver unit 02 stops transmitting the switching media stream after receiving the stop notification.

The following three systems are taken as an example to describe the above system and method in detail. In the three schemes, the switching stream generating unit is set in the cache entity, that is, the generating function of the switching entity to complete the switching media stream is taken as an example.

Scheme 1, its structure is shown in Figure 4.1, where the dotted lines I I and 12 represent signaling channels, and the solid lines P1, P2 and P3 represent media channels.

In this scheme, the media provider 303 sends a normal media stream to the caching entity 302 via P2. The cache entity 302 generates a switching media stream and buffers it; the media receiver 304 sends a handover request to the cache entity 302 through the II, and after receiving the handover request, the cache entity 302 immediately transmits the switched media stream of the target channel to the media receiver 304 through P1, and The authentication request is sent to the media provider 303 through 12; the media provider 303 performs authentication. After the authentication succeeds, the media provider 303 sends the normal media stream of the target channel to the media receiver 304 through P3, and passes the 12-way cache entity. 302, sending a stop notification, after receiving the stop notification, the cache entity 302 stops transmitting the switched media stream of the target channel; if the authentication fails, the media provider 303 does not send the normal media stream of the target channel to the media receiver 304, and passes the 12-way The cache entity 302 sends a stop notification, and the cache entity 302 stops transmitting the switched media stream of the target channel after receiving the stop notification and/or to a certain time limit. The stop notification may be an authentication response sent by the media provider 303 to the cache entity.

The system and specific implementation process of the first scheme are described below by taking the IPTV channel switching on the traditional IP network as an example. As shown in Figure 4.2, in the channel switching system of the traditional IPTV service, the media provider is an IPTV middleware, and its functions include: user authentication, service request processing, IPTV content management, and media stream distribution scheduling; The cache entity uses Cache; the media receiver uses STB. At this time, the media transmission channel P3 is formed by a combination of the transmission channels P1 and P2 through the Cache.

The flow chart of the method for quickly switching the IPTV channel by the system shown in Fig. 4.2 is shown in Fig. 4.3, wherein the solid line indicates the transmission step of the media stream, and the broken line indicates the transmission step of the signaling. The process includes the following steps:

Step 401: The IPTV middleware sends a normal media stream to the Cache through the P2.

Step 402: The Cache receives the normal media stream to form a switched media stream and performs buffering.

Step 403: The Cache sends a normal media stream of the current channel to the STB through P1.

Step 404: When the STB wants to switch channels, send a handover request to the Cache through I I;

The handover request includes user location information and a target channel identifier, and requests the PDCCH to switch media streams of the target channel, and also requests the IPTV middleware to the normal media stream of the target channel.

Step 405: After receiving the handover request, the Cache sends the switching media stream of the target channel to the STB. In this step, the Cache finds the switching medium of the target channel according to the target channel identifier in the handover request. The body stream is sent to the STB according to the user location information in the handover request.

Step 406: The Cache sends an authentication request to the IPTV middleware through 12;

Step 405 and step 406 may be performed simultaneously, or may be performed sequentially in a short time, and the order may be arbitrary.

Step 407: IPTV middleware is authenticated;

Step 408: The IPTV middleware sends the authentication response to the Cache to notify the authentication failure or success. If the authentication fails, the step 409 is not performed, and the step 412 is not performed. If the authentication is successful, step 409 is performed;

Step 409: The IPTV middleware sends the normal media stream of the target channel to the Cache through the P2. Step 410: The IPTV middleware sends the handover response notification to the STB through the I1 to accept or not accept the handover request.

The steps 408 and 409 have no fixed sequence, and may be performed simultaneously. Step 411: The Cache stops sending the switched media stream of the target channel.

Step 412: The Cache sends a normal media stream of the target channel to the STB through P1.

In an embodiment of the foregoing solution, the authentication unit is disposed in the IPTV middleware.

Scheme 2, its structure is shown in Figure 5. 1, where dashed lines 12 and 13 represent signaling channels, and solid lines P1, P2 and P3 represent media channels.

In this scheme, the media provider 303 sends a normal media stream to the caching entity 302 via P2, the caching entity 302 generates a switching media stream and caches it; the media receiver 304 sends a handover request to the media provider 303 via the media provider 303, the media provider 303, by 12, forwards the handover request to the cache entity 302. After receiving the handover request, the cache entity 302 immediately sends the switched media stream of the target channel to the media receiver 304 through P1; the media provider 303 determines the authentication request according to the handover request. After the authentication succeeds, the media provider 303 sends the normal media stream of the target channel to the media receiver 304 through P3, and can send a stop notification to the cache entity 302 through 12, and the cache entity 302 receives the media provider 303. Stop the notification, and/or stop transmitting the switching media stream of the target channel after a certain timing period; if the authentication fails, the media provider 303 does not send the media receiver 304 The normal media stream of the target channel can simultaneously send a stop notification to the cache entity 302 through 12, the cache entity 302 receives a stop notification from the media provider 303, and/or stops transmitting the switched media stream of the target channel after a certain time limit. . The stop notification may be an authentication response sent by the media provider 303 to the cache entity.

The following describes the system and specific implementation flow of the second solution by taking the channel switching of the bearer and the control as an example. As shown in Figure 5.2, the layered design of the NGN network architecture separates the control and authentication functions of the IPTV service from the media server to form an IPTV service control entity. At this time, the user's authentication is completed by the IPTV service control entity. The cache entity uses Cache; the media receiver uses STB. At this time, the media transmission channel P3 is formed by a combination of the transmission channels PI and P2 through the Cache; the signaling channels 12 and 13 are transferred, and the signaling channel 14 is newly added for the control of the media server by the IPTV control entity, and the protocol may be H. 248, SIP, etc.

The flow chart of the method for quickly switching the IPTV channel by the system shown in FIG. 5.2 is shown in FIG. 5. 3, wherein the solid line indicates the transmission step of the media stream, and the broken line indicates the transmission step of the signaling. The process includes the following steps:

Step 501: The media server sends a normal media stream to the Cache through the P2.

Step 502: The Cache receives the normal media stream and forms a switching media stream and performs buffering. Step 503: The Cache sends the current channel normal media stream to the STB through the P1.

Step 504a: The STB sends a handover request to the Cache through the I I;

Step 505: The Cache sends the switched media stream of the target channel to the STB according to the target channel identifier and the user location information in the handover request through P1.

Step 504b: The STB sends an authentication request to the IPTV service control entity through 13;

The authentication request includes authentication information.

Steps 504a and 504b are not in a fixed order, and may also be performed simultaneously.

Step 506: The IPTV service control entity performs authentication. After the authentication succeeds, the process proceeds to step 507. If the authentication fails, step 508 is performed, and steps 509 and 511 are not performed.

Step 507: The IPTV service control entity sends a target normal flow request to the media server by using 14 And receiving a response sent by the media server;

Step 508: The IPTV service control entity sends an authentication response to the Cache.

Step 509: The media server sends a normal media stream of the target channel to the Cache through the P2. Step 510: The Cache stops sending the switched media stream of the target channel to the STB.

Step 511: The Cache sends the normal media stream of the target channel to the STB through P1.

The IPTV service control entity described in the embodiment of the second solution completes the function of the authentication unit.

Scheme 3, its structure is shown in Figure 6.1, where the dotted lines I I and 13 represent signaling channels, and the solid lines P1, P2 and P3 represent media channels.

In this solution, the media provider 303 sends a normal media stream to the cache entity 302 through P2, and the cache entity 302 generates a switch media stream and caches it; the media receiver 304 sends a handover request to the cache entity 302 through II, and provides the media to the media through the 13 The sender sends an authentication request; after receiving the handover request, the cache entity 302 immediately sends the switched media stream of the target channel to the media receiver 304 through P1; the media provider 303 performs authentication after receiving the authentication request, and after the authentication succeeds, the media The provider 303 sends a handover request acceptance notification to the media receiver 304 through 13 while transmitting the normal media stream of the target channel to the media receiver 304 via P3; after receiving the notification of the handover request, the media receiver 304 sends the notification to the cache entity 302. The sending stop notification, the buffering entity 302 stops receiving the switching media stream of the target channel after receiving the stop notification, or may set a timing time for the buffering entity 302 to deliver the switching media stream, and after the timing time limit, the cache entity 302 automatically stops sending the target. Channel switching media stream, At this point the media recipient 304 may not send a stop notification to the caching entity 302. The above two methods of triggering the buffer entity 302 to stop transmitting the target channel switching media stream may also be used at the same time.

The following describes the system and specific implementation flow of the third solution by taking the channel switching in the IMS network architecture as an example. As shown in Figure 6.2, under the IMS network architecture, the IMS core is used for control of call, routing, media negotiation, etc.; the IPTV service control layer is responsible for authentication, and service scheduling and distribution; HSS is used for storage correlation. Authentication data; the media server is responsible for the transmission function of the media. In the IMS network, the media receiver can be the UE; the media provider can be the multimedia resource control function (MRFC, Multimedia Resource Function Controller / Multimedia Resource Function Processor (MRFP); The cache entity can be set in the Border Gateway Function (BGF) or Broadband Remote Access System (BRAS) or digital User Loop Access Multiplexer (DSLAM) or other access network entity.

A flowchart of a method for rapidly switching an IPTV channel by the system shown in FIG. 6.2 is shown in FIG. 6.3, wherein a solid line indicates a transmission step of a media stream, and a broken line indicates a transmission step of signaling. In the following embodiment, the cache entity is set in the BGF, and the BGF stops the delivery of the switching flow in a timed manner. The process includes the following steps:

Step 601: The MRFC/MRFP sends the current channel normal media stream to the UE through P3.

Step 602: The MRFC/MRFP sends a normal media stream to the BGF through P2.

Step 603: The BGF receives the normal media stream to form a switching media stream and performs buffering.

Step 604a: The UE sends a handover request to the BGF through the II.

Step 605: The BGF sends a switching media stream of the target channel to the UE through the P1, and starts the timer at the same time;

Step 604b: The UE sends a handover request to the IPTV service control layer via the IMS core through the IMS core. The steps 604a and 604b are not performed in a fixed sequence, and may be performed simultaneously. Step 606: The IPTV service control layer passes the 16 to the home subscriber. After the server (HSS) obtains the user authentication information, the authentication is performed; after the authentication succeeds, the process proceeds to step 607; if the authentication fails, the authentication failure notification is sent to the UE, and then step 608 is performed, and step 609 is not performed;

Step 607: The IPTV service control layer requests the normal media stream of the target channel by the MRFC/MRFP through 15 and receives a response.

Step 608: The IPTV service control layer sends a handover response to the UE by using 14 and 13;

Step 609: The MRFC/MRFP sends a target channel normal service flow to the UE through P3.

The steps 608 and 609 have no fixed sequence, and may be performed simultaneously.

Step 610: When the timer expires, the BGF stops sending the switched media stream of the target channel to the UE. The method used by the BGF to stop transmitting the switched media stream is to use a timer. As soon as the timer expires, the BGF stops transmitting the switching media stream. The timing of the timer is set to Τ, which is generally greater than the time taken by the media receiver to send a handover request to the media provider to deliver the normal media stream.

In the embodiment of the third solution, the IMS core and the HSS jointly perform the functions of the authentication unit.

It can be seen from the above description that the method and system provided by the embodiments of the present invention set a cache entity to cache a switched media stream, and immediately send a switching media stream to a media receiver after receiving the handover request, thereby reducing the network. The delay caused by the transmission process; in the process of making a handover request to the media provider, the media receiver may first receive the switched media stream of the target channel, thereby reducing the delay caused by the signaling plane performing the handover request. Therefore, the method and system provided by the embodiments of the present invention reduce the delay in the IPTV channel switching process.

Further, the method and system provided by the embodiments of the present invention may introduce an authentication process, and in the process of authenticating, the media receiver may first receive the switched media stream of the target channel sent by the cache entity, and also reduces the The delay caused by the signaling interaction in the authentication process.

Further, the method and system provided by the embodiments of the present invention can be used not only for fast switching of IPTV channels when transmitting in multicast mode, but also for fast switching of IPTV channels when transmitting in unicast mode.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalents, improvements, etc. made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Claims

Claim

A method for switching a network television channel, the method comprising: the cache entity buffering the generated switched media stream, and after receiving the handover request, transmitting the switched media stream of the target channel to the media receiver; After being accepted, the media provider sends a normal media stream of the target channel to the media recipient.

The method for switching a network television channel according to claim 1, wherein the process of generating a switched media stream is: the media provider sends a normal media stream to a cache entity, and the cache entity is the normal media. The stream is modified to generate a switched media stream; or

The media provider modifies the normal media stream to generate a switched media stream, and then sends the buffer to the cache entity for caching; or

The media provider sends the normal media stream to a separate device, and the independent device modifies the normal media stream to generate a switched media stream, which is then sent to the cache entity for caching.

The method for switching a network television channel according to claim 1, wherein the handover request is directly sent by the media receiver to a cache entity, and the cache entity is forwarded to the media provider; or Is sent by the media receiver to the media provider, and then forwarded to the cache entity by the media provider; or directly sent by the media receiver to the cache entity and the media provider.

The method for switching a network television channel according to claim 1, wherein the handover request includes a target channel identifier;

Transmitting, by the cache entity, a switched media stream of the target channel to the media receiver according to the target channel identifier in the received handover request;

The media provider sends a normal media stream of the target channel to the media recipient based on the target channel identifier in the received handover request.

The method for switching a network television channel according to claim 1, wherein the method further comprises: after the handover request is accepted, the buffer entity stops sending the switched media stream of the target channel to the media receiver; or

After a certain time limit, the cache entity automatically stops sending the switching media of the target channel to the media receiver. Stream.

The method for switching a network television channel according to claim 1, wherein the switching request includes an authentication request;

The handover request is accepted as an authentication success;

The media receiver sends the authentication request to the cache entity, and the cache entity sends the authentication request to the authentication unit for authentication. After the authentication succeeds, the authentication unit notifies the media provider that the handover request is accepted; Or,

The media receiver sends the authentication request to the cache entity, and the cache entity forwards the authentication request to the media provider, and the media provider sends the authentication request to the authentication unit for authentication. After the authentication succeeds, the authentication unit notifies the media provider that the handover request is accepted; or

The media receiver directly sends the authentication request to the authentication unit, and the authentication unit performs authentication. After the authentication succeeds, the media provider is notified that the handover request is accepted.

7. The method of switching a network television channel according to claim 1, wherein the media provider sends the normal media stream of the target channel to the media receiver as: the media provider directly sends the normal media of the target channel to the media receiver. The stream, or the media provider first sends a normal media stream of the target channel to the cache entity, and then forwarded to the media receiver by the cache entity.

The method for switching a network television channel according to claim 3, wherein in the IP multimedia subsystem network, the media receiver is a user equipment; and the media provider is a multimedia resource control function or a multimedia resource. Processing function; the cache entity is disposed in a border gateway function or a broadband remote access system or a digital subscriber loop access multiplexer or other access network entity;

The handover request is directly sent by the user equipment to the cache entity or the multimedia resource control function or the multimedia resource processing function.

The method for switching a network television channel according to claim 6, wherein in the IP multimedia subsystem network, the media receiver is a user equipment; and the media provider is a multimedia resource control function or a multimedia resource. Processing function; the cache entity is set in a border gateway function or a broadband remote access system or a digital subscriber loop access multiplexer or other access network entity; the authentication list The element includes: a network television service control layer and a home subscriber server;

The user equipment sends an authentication request to the network television service control layer, and the network television service control layer obtains the authentication information of the user from the home user server according to the user information in the authentication request, and performs authentication, after the authentication succeeds. The network television service control layer notifies the multimedia resource control function or the multimedia resource processing function switching request to be accepted.

The method according to claim 7, wherein in the IP multimedia subsystem network, the media receiver is a user equipment; the media provider is a multimedia resource control function or a multimedia resource processing function;

The media provider sends the normal media stream of the target channel to the media receiver as follows: After receiving the handover request, the multimedia resource control function or the multimedia resource processing function directly sends the normal media stream of the target channel to the user equipment.

A system for switching a network television channel, the system comprising: a handover flow generation unit, a cache entity, a media provider, and a media receiver;

The switching stream generating unit receives the normal media stream sent by the media provider and generates a switching media stream, and sends the packet to the cache entity;

The buffering entity buffers the switched media stream sent by the switching stream generating unit, and after receiving the switching request sent by the media receiver or the media provider, sends the switching media stream of the target channel to the media receiver; receiving the switching of the media receiver After the request is forwarded to the media provider or not to the media provider; the media provider sends a normal media stream to the switching stream generating unit, and after the switching request is accepted, the normal media stream of the target channel is sent to the media receiver; After the handover request sent by the media receiver is forwarded to the cache entity or not forwarded to the cache entity;

12. The system for switching network television channels according to claim 11, wherein in the IP multimedia subsystem system, the cache entity is set in a border gateway function or a broadband remote access system or a digital subscriber loop access complex. In the consumer or other access network entity; The media provider is a multimedia resource control function or a multimedia resource processing function; the media receiver is a user equipment.

The system for switching network television channels according to claim 11, wherein the switching stream generating unit is an independent device, or is disposed in a cache entity, or is disposed in a media provider.

The system for switching network television channels according to claim 11, wherein the media provider sends a stop notification to the cache entity after the handover request is accepted, or sends a handover request to the media receiver to be notified. ;

After receiving the notification that the handover request is accepted, the media receiver sends a stop notification to the cache entity; after receiving the stop notification or after a certain time limit, the cache entity stops transmitting the switched media stream of the target channel to the media receiver.

The system for switching network television channels according to claim 11, wherein the system further comprises: an authentication unit;

The switching request includes an authentication request;

The authentication unit, after receiving the authentication request sent by the cache entity or the media provider or the media receiver, performs authentication, and after the authentication succeeds, notifying the media provider that the handover request is accepted;

The cache entity is further configured to: after receiving the handover request of the media receiver, send the authentication request to the authentication unit; or

The media receiver is further configured to directly send the authentication request to the authentication unit; or

The media provider is further configured to send the authentication request to the authentication unit.

The system for switching network television channels according to claim 15, wherein in the IP multimedia subsystem network, the authentication unit comprises: a network television service control layer and a home subscriber server;

After receiving the authentication request sent by the media receiver, the network television service control layer obtains the authentication information of the user from the home subscriber server according to the user information in the authentication request, and after the authentication succeeds, notifies the media to provide the authentication request. The switch request is accepted;

The home server is stored and the authentication information is stored.

17. A cache entity, the cache entity comprising: a cache unit, and a transceiver unit;

a cache unit, configured to cache the switched media stream;

The transceiver unit receives the switched media stream and sends it to the buffer unit; after receiving the handover request, sends the switched media stream in the buffer unit; after receiving the handover request of the media receiver, forwarding the message to the media provider or not to the media provider.

The cache entity according to claim 17, wherein the cache entity further comprises: a switch flow generation unit, configured to modify the normal media stream to form a switched media stream, and send the packet to the transceiver unit.

The cache entity according to claim 17, wherein the transceiver unit further stops transmitting the switched media stream after the handover request is accepted.

The cache entity according to claim 17, wherein the cache entity further comprises a timing unit, configured to set a timing time limit, and send a stop notification to the transceiver unit when the timing time expires; the transceiver unit receives the stop After the notification, stop sending the switching media stream.