WO2009080112A1

WO2009080112A1 - Method and apparatus for distributing media over a communications network

Info

Publication number: WO2009080112A1
Application number: PCT/EP2007/064445
Authority: WO
Inventors: Andreas Ljunggren; Mikael Lind; Robert Skog
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2007-12-21
Filing date: 2007-12-21
Publication date: 2009-07-02
Also published as: GB2468058A; GB201008289D0

Abstract

A proxy node and method for use in an Internet Protocol television peer to peer network. A proxy node includes a receiver for receiving media data on behalf of an end user device. The proxy node further comprises a memory for storing the media data; and a transmitter for sending at least some of the received media data to a further node in the peer to peer network on behalf of the end user device. In this way, further nodes believe that the end user device is sending as much data as it is receiving.

Description

Method and Apparatus for Distributing Media over a Communications Network

TECHNICAL FIELD

The invention relates to the field of distributing media over a communications network.

BACKGROUND

TV services broadcast over an IP network are referred to as IPTV. IPTV is typically broadcast using a broadband access network, in which channels are transmitted over a broadband network from a super head-end down to an end-user's set top box (STB).

Linear content delivery, in which all channels in a subscription are simultaneously delivered to a user's set top box (STB) is not suitable for IPTV, as IPTV has limited bandwidth available over a broadband connection. A typical ADSL broadband connection provides a capacity of between 3 and 8 Mbps, and ADSL2 promises to deliver up to 25 Mbps downstream, whereas VDSL can provide a capacity of greater than 30 Mbps. Standard quality MPEG 2 IPTV content requires 2Mbps per channel, and HDTV will require around 8-10 Mbps per channel. The MPEG 4 standard will approximately halve the bandwidth required to deliver IPTV content with the same quality. Nevertheless, the available bandwidth is a scarce resource, and IPTV solutions must limit the number of channels that can be delivered simultaneously.

Figure 1 illustrates a known way of distributing media in which an IPTV media stream originates in service provider network 1 , is passed a core network 2, is further passed into a metro network 3, and finally is sent via access networks to each home network 4 that contains an STB that wishes to receive the media stream. Networks can quickly become saturated due to heavy traffic loads. In order to mitigate this problem, content can be multicast to reduce bandwidth demands for broadcast TV distribution. Furthermore, Video on Demand (VoD) services can be handled by VoD cache servers located close to the end-user. However, such caches require additional investment, and many routers would need to be replaced, as existing routers may not support IPTV multicasts.

It is known to distribute an IPTV service using a Peer to Peer (P2P) network, as illustrated in Figure 2. Each STB is a peer in the network. An IPTV media stream can be delivered to a STB from another STB, from a media injector from which the stream originates, or from any other peer in the network.

It is a requirement of current P2P based distribution systems that each peer (and hence each STB) in the network is connected via a symmetrical connection. This means that each peer should be capable of transmitting the same amount of data as it can receive. This is to ensure that the network is balanced, and that content can be delivered to a STB and distributed throughout the network.

In some circumstances, it is not practical for a STB to be connected via a symmetrical connection. For example, if a STB is connected to the network via an ADSL line with a capacity of 3 Mbps, it will be able to receive a media stream at Mbps, but would not be able to transmit the media stream at the same rate.

SUMMARY

The inventors have realised the problem associated with asymmetrical connections in an IPTV P2P network, and have devised a method and apparatus to mitigate these problems. According to a first aspect of the invention, there is provided a proxy node and method for use in an Internet Protocol television peer to peer network. A proxy node includes a receiver for receiving media data on behalf of a first node. The proxy node further comprises a memory for storing the media data; and a transmitter for sending at least some of the received media data to a further node in the peer to peer network on behalf of the first node. In this way, further nodes believe that the first node is sending as much data as it is receiving.

Optionally, the proxy node is selected from any of a Digital Subscriber Line Access Multiplexer, a Wireless Local Area Network Access Point, an L3 Switch, and an L3 Router. Any suitable node may be used, an in particular nodes used in proximity to end-user devices.

The proxy node optionally comprises a receiving function arrange to receive instructions from the first node. This allows the first node to instruct the proxy node when, for example, the first node is a set top box and the user wishes to view a different channel. In some circumstances, the first node may be a further proxy node. As an option, the received media data is received from a peer in the peer to peer network or a media injector. Media data may be received from either or both of these sources.

Optionally, the proxy node comprises a forwarding function for forwarding the media data to the first node. This is to allow the user of the first node to view the media data in the case where the first node is a set top box.

The first node is optionally non-peer to peer enabled. However, by accessing the proxy function, the non-peer to peer enabled first node can access a peer to peer IPTV communications network.

The proxy node optionally comprises a database arranged to store Video on Demand media content.

The first node is optionally selected from any of an end user device and a further proxy node, and the further node is optionally selected from any of a further end user device and a further proxy node. Where the further end user device is a further proxy node, the further proxy node acts on behalf of a further end user device.

As an option, the proxy node further comprises means for receiving media data from an end user device, and means for transmitting the end user device media data to a further node in the peer to peer network on behalf of the end-user device. In this instance, the end-user device is effectively acting as a media injector, but by injecting media via the proxy node, the proxy node can disguise the fact that it may be acting on behalf of the end-user device (and probably a plurality of end-user devices) and the end-user device can disguise its identity.

According to a second aspect of the invention, there is provided a method of acting on behalf of a peer node in peer to peer media communications network. A proxy node located in the peer to peer network receives media data on behalf of the peer node. The media data is stored at the proxy node and sent to the peer node. At least a portion of the media data is also sent to a further node in the peer to peer network. The method optionally comprises receiving, from the peer node, instructions. In this way, the peer node can inform the proxy node of changes, for example when a user wishes to switch channel.

The media data is optionally received from a peer in the peer to peer network or a media injector.

According to a third aspect of the invention, there is provided a proxy node for use in a Store and Forward communications network. The proxy node comprises a receiver for receiving, on behalf of an end user device, media data, a memory for storing the media data, and a transmitter for sending at least some of the received media data to a further node in the Store and Forward network.

According to a fourth aspect of the invention, there is provided apparatus for use in distributing media over a communications network, the apparatus comprising means for performing the method as described in the first aspect of the invention.

According to a fifth aspect of the invention, there is provided a program for controlling an apparatus to perform the method as described in the second aspect of the invention.

According to a sixth aspect of the invention, there is provided a program which, when loaded into an apparatus, causes the apparatus to become an apparatus according to the fifth aspect of the invention.

According to a seventh aspect of the invention, there is provided a program according to the fifth or sixth aspects of the invention, carried on a carrier medium. The carrier medium is optionally a storage medium.

According to an eighth aspect of the invention, there is provided a storage medium containing a program according to any one of the sixth or seventh aspects of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates schematically in a block diagram an architecture for the distribution of IPTV; Figure 2 illustrates schematically in a block diagram an architecture for the distribution of IPTV in a peer to peer network;

Figure 3 illustrates schematically in a block diagram a media injector and two Set Top Boxes;

Figure 4 illustrates schematically in a block diagram the signalling required to initiate an IPTV broadcast with a first Set Top Box;

Figure 5 illustrates schematically in a block diagram the signalling required to initiate an IPTV broadcast with a further Set Top Box;

Figure 6 illustrates schematically in a block diagram keep alive messages sent by a Set Top Box;

Figure 7 illustrates schematically in a block diagram a proxy node according to an embodiment of the invention;

Figure 8 illustrates schematically in a block diagram an architecture of a network including a proxy node according to an embodiment of the invention; and

Figure 9 is a flow diagram illustrating the basic steps of an embodiment of the invention.

DETAILED DESCRIPTION

The following description sets forth specific details, such as particular embodiments, procedures, techniques, etc. for purposes of explanation and not limitation. In some instances, detailed descriptions of well known methods, interfaces, circuits, and devices are omitted so as not obscure the description with unnecessary detail. Moreover, individual blocks are shown in some of the drawings. It will be appreciated that the functions of those blocks may be implemented using individual hardware circuits, using software programs and data, in conjunction with a suitably programmed digital microprocessor or general purpose computer, using application specific integrated circuitry, and/or using one or more digital signal processors. IPTV P2P requires a media injector in order to introduce the IPTV media stream, although the media injector is not a true peer in the network in the sense that it sends media data but does not receive media data from the peers. This is illustrated in Figure 3, in which STB 1 receives the IPTV media stream from both STB2 and an IPTV Server 6, which injects either streaming content or content from a database 7 using a P2P media injector 8. Note that other network nodes may be peers in the network.

Referring to Figure 4, the signalling required to initiate an IPTV broadcast with a first STB is shown. A video decoder 9 in STB1 receives an instruction from a user to start channel X. This is relayed to the P2P function in STB1 , which sends a request to a STB manager 10 in the IPTV back-end to join channel X. The STB Manager 10 returns a peer list to the P2P function in STB1 , but no IPTC media stream. The peer list includes the P2P media injector 8 (referred to as STBO). The P2P function in STB1 then sends a request to join channel X to STBO. STBO receives an IPTV media stream from an IPTV media stream source 7, and sends a peer list and an IPTV media stream comprising fragments of frames to the P2P function of STB1. The P2P function of STB1 sends the frames to the video decoderθ in STB1 , which can then show the IPTV media stream to the user.

Referring to Figure 5, an example of signalling required to initiate an IPTV broadcast with a further STB is shown. It is assumed that STB1 is already receiving an IPTV media stream from STBO. When the user of STB2 wishes to receive channel X, she sends an instruction to logic within STB2, which is relayed to a P2P function in STB2. The P2P function in STB2 sends a request join channel X to the STB manager 10. The STB manager 10 returns a peer list but no payload to STB2. The peer list includes STBO and STB1 , as these are both possible sources for the IPTV media stream. The P2P function in STB2 then sends a request to each of STBO and STB1 to join channel X. STBO and STB1 each send a peer list and IPTV data stream to the P2P function in STB2, which passes the frames of the IPTV media stream to the video decoder.

All peers in the P2P network send each other "keep alive" messages, as illustrated in Figure 6, to ensure that each STB is included in the list of peers and can both send and receive IPTV media streams. Note that the term "IPTV media stream" is used herein to refer to media data having real time requirements, and includes Video on Demand, user defined TV content, interactive TV, interactive or co-operative games, or audio media. The media stream is to be delivered to the user such that the user can observe the media content at a constant rate without interruptions or delays. There is some latency in the P2P network, caused by the buffer in each STB and the time it takes to establish communication between peers. The media stream may come from a media injector originally, but can also be received from other nodes within the network. A media stream contains both payload data (that is, data used for showing the media channel) and metadata (which includes data describing the media stream).

At a high level, the invention is to introduce a proxy node near to the end-user equipment that can send and receive media streams on behalf of the end user. For peers with an asymmetrical connection, the proxy node will make those peers appear to be good peer to peer citizens as far as the other peers are concerned. Furthermore, the proxy node can be used to disguise the fact that it is acting on behalf of a plurality of clients. The proxy node may be a new entity within the network, or may be provided as a function located in an existing network node.

An example of a node that could be used as a proxy node in this application is a Digital Subscriber Line Access Multiplexer (DSLAM). A DSLAM, illustrated in Figure 7, is a network device, located near the end user's location, that connects multiple Digital Subscriber Lines (DSLs) to a high-speed Internet backbone line using multiplexing techniques. The DSLAM 12 has a receiver 13 for receiving media streams from a plurality of sources, a processor 14, a memory 15 for caching media streams, and a transmitter 16 for sending media to other peers in the network. A typical DSLAM may serve 2000 subscribers, which would allow a single media stream to be sent to 2000 STBs.

The proxy node, having a memory, performs dynamic buffering on behalf of the end- user, and can dynamically join networks as required by the end-user. As illustrated in Figure 8, the proxy node 12 is seen simply as another peer in the network 17, and can be used to store real-time media streams in the content distribution network. Referring to figure 9, the basic steps according to an embodiment of the invention are illustrated in a flow diagram. The following numbering refers to the numbering of Figure 9:

S1. The proxy node receives IPTV media data on behalf of the end user;

52. The proxy node stores the received media data in a buffer;

53. The media data is sent to the end user for the end user to view the content of the media data;

54. The proxy node sends at least a portion of the media data to a further node in the network on behalf of the end user, therefore making it appear to other nodes in the peer to peer network that the end user is operating a symmetrical connection or shielding the identity of the end user, and disguising the fact that the proxy node is acting on behalf of a plurality of end-users. Steps S3 and S4 may be performed sequentially or concurrently.

Of course, the proxy node can receive instructions from each end user device that it is serving. Such instruction, include requests to change channel, or take part in interactive aspects of the IPTV service.

The proxy node also allows for less reliable connections towards end customers, since unlike traditional multicast/unicast IPTV, P2P and Store and Forward networks allow retransmission of media streams. This requires that the average bandwidth minus any packet loss is sufficiently high to sustain the target bit rate.

An advantage to the network operator of providing a proxy node such as a DSLAM is that the network operator can make a charge to the IPTV subscriber for providing a service of compensating for the user's asymmetrical connection.

In a further embodiment of the invention, the proxy node is able to switch between P2P and traditional multicast/unicast IPTV services in both directions. The proxy node receives P2P IPTV media streams. Existing STBs, which are not P2P enabled, can access the P2P IPTV media streams via the proxy node. Similarly, STBs that are P2P enabled can use the proxy node to access IPTV services that are distributed using a multicast over the network.

The invention allows users with asymmetric connections to utilize P2P based distribution of real-time & VOD services. In one embodiment, it allows users with existing, non-P2P systems to join new services being deployed on top of P2P. It also allows users having P2P enabled equipment to access legacy systems that utilize multicast IPTV. Furthermore, the invention ensures that the P2P network remains balanced.

The proxy node can also act on behalf of an end user device when the end user device is the source of the media stream (effectively, the end user device is acting as a media injector). In this case, the proxy node can disguise the fact that there are a plurality of end-user devices located "behind" the proxy node in the network, as the proxy node effectively constructs its own network subnetwork. The proxy node can also allow an end-user device to hide its identity in the network when the end-user device is acting in the role of a media injector.

Although various embodiments have been shown and described in detail, the claims are not limited to any particular embodiment or example. For example, whilst the method and apparatus is described in the context of a peer to peer network, it may also be used in a Store and Forward network. None of the above description should be read as implying that any particular element, step, or function is essential such that it must be included in the claims' scope. The scope of protection is defined by the claims.

Claims

CLAIMS:

1. A proxy node for use in a peer to peer media communications network, the node comprising: a receiver for receiving, on behalf of a first node , media data; a memory for storing the media data; and a transmitter for sending at least some of the received media data to a further node in the peer to peer network.

2. The proxy node according to claim 1 , wherein the proxy node is selected from any of a Digital Subscriber Line Access Multiplexer, a Wireless Local Area Network Access Point, an L3 Switch, and an L3 Router.

3. The proxy node according to claim 1 , or 2, further comprising a receiving function arrange to receive instructions from the first node.

4. The proxy node according to claim 1 , 2 or 3, wherein the received media data is received from a peer in the peer to peer network

5. The proxy node according to claim 1 , 2 or 3, wherein the received media data is received from a media injector.

6. The proxy node according to any one of claims 1 to 5, further comprising a forwarding function for forwarding the media data to the first node.

7. The proxy node according to claim 6, wherein the first node is non-peer to peer enabled.

8. The proxy node according to any one of claims 1 to 7, further comprising a database, the database arranged to store Video on Demand media content.

9. The proxy node according to any one of claims 1 to 8, wherein the first node is selected from any of an end user device and a further proxy node.

10. The proxy node according to any one of claims 1 to 9, wherein the further node is selected from any of a further end user device and a further proxy node.

1 1. The proxy node according to any one of claims 1 to 10, further comprising: means for receiving end user device media data from an end user device; and means for transmitting the end user device media data to a further node in the peer to peer network on behalf of the end-user device.

12. A method of acting on behalf of a peer node in peer to peer media communications network, the method comprising: at a proxy node located in the peer to peer network receiving, on behalf of the peer node, media data; storing the media data; sending the media data to the peer node; and sending at least a portion of the media data to a further node in the peer to peer network.

13. The method according to claim 12, further comprising receiving, from the peer node, instructions.

14. The method according to claim 12 or 13, wherein the media data is received from a peer in the peer to peer network

15. The method according to claim 12 or 13, wherein the media data is received from a media injector.

16. A proxy node for use in a Store and Forward communications network, the node comprising: a receiver for receiving, on behalf of an end user device, media data; a memory for storing the media data; and a transmitter for sending at least some of the received media data to a further node in the peer to peer network.

17. An apparatus for use in distributing media over a communications network, the apparatus comprising means for performing the method as claimed in any one of claims 12 to 15.

18. A program for controlling an apparatus to perform a method as claimed in any one of claims 12 to 15.

19. A program which, when loaded into an apparatus, causes the apparatus to become an apparatus as claimed in claim 17.

20. A program as claimed in claim 18 or 19, carried on a carrier medium.

21. A program as claimed in claim 20, wherein the carrier medium is a storage medium.

22. A storage medium containing a program as claimed in any one of claims 17 to 21.