GB2440581A

GB2440581A - Preloading and download of content to a mobile device

Info

Publication number: GB2440581A
Application number: GB0615482A
Authority: GB
Inventors: Angelo Centonza
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2006-08-04
Filing date: 2006-08-04
Publication date: 2008-02-06
Anticipated expiration: 2026-08-04
Also published as: GB0615482D0; GB2440581B; WO2008015468A1

Abstract

A method of transferring data to a mobile device 2 comprises broadcasting service content from a network 1 to one or more mobile devices having a pre-existing relationship with a service provider; starting download of the content at each mobile device at a session start time; and signalling a play out start time to the mobile device. Acceptance of the service by the mobile device is requested and if the service has been accepted, the play out on the mobile device starts at the predetermined play out start time; and the mobile device continues to download and play out the remainder of the session. This provides a trade-off of delivery mode between pure content downloading and content streaming. Content can be downloaded at a lower bit rate than the content was encoded at. The time delay 6 the mobile device has to wait before starting play of the content ensures no interruption of play.

Description

A METHOD OF TRANSFERRING DATA TO A MOBILE I)EV ICE This invention

relates to a niethod of transferring data to a mobile device, in particular audio and video data.

Mobile applications employing streaming of audio and video contents are becoming more and more frequent in wireless networks. One popular examp le of the use of such applications is mobile TV. However, content streaming is often not needed due to the fact that services are prescheduled, as it is for standard TV programs and content can he downloaded in advance on the user's terminals instead of being streamed in real time. Content downloading puts less stress on network resource allocation and improves quality of service (QoS) due to the fact that the downloading can be performed during low load times and in acknowledged niode. However, downloading content also increases the requirements on terminal storage space and does not allow for immediate delivery of content that has just become available to the network.

In accordance with the present invention, a method of transferring data to a mobile device comprises broadcasting service content from a network to one or more mobile devices having a pre- existing relationship with a service provider; starting download of the content at each mobile device at a session start time: signalling a play out start time to the mobile device; requesting acceptance of the service by the mobile device; if the service has been accepted, starting the play out on the mobile device at the predetermined play out start time; and continuing to download and play out the remainder of the session.

The present invention provides a trade off delivery mode between pure content downloading and content streaming. Unlike pure downloading, the invention still gives the opportunity to deploy content that has just become available to tl network but unlike streaming. the invention does not require large amounts of resource in a short period of time. instead it spreads the resources needed along a longer time interval thereby meaning that other services running in parallel do not have to be blocked due to lack of resources. By opportune signalling between the network and terminals the invention also gives a perceived real-time experience to the user.

Preferably, if the service has not been accepted at the end of the download, the downloaded content is deleted from the mobile device.

Preferably, the play out start time is determined in the network based on preload hit rate; content encoding hit rate; and total content size.

Preferably, the play out start time is signalled from the network at the session start time.

Preferably, if the service is refused at any time, the download ceases and already downloaded content is deleted.

Preferably, previously stored data on the mobile device is displayed for at least part of the delay between the session start time and the play out start time.

An example of a method of transferring data to a mobile device according to the present invention will now be described with reference to the accompanying drawings in which: Figure 1 shows a first arrangenient for transferring content from a BM-SC to a mobile device in accordance with the present invention; and, Figure 2 illustrates signalling sequences for the method of the present invention with multiple devices.

There are many technologies providing services like audio/video streaming content for applications like mobile TV, so the approach towards the problem of optimum deployment of such services is different depending on the technology context.

Conventionally, deployment of tlse types of content is either as streaming, or as download and play. Streaming consists of a continuous unacknowledged transmission of the audio/video content at the bit rate in which the content has been encoded and for a length of time equal to the duration of the audio/video sequence. Since streaming requires a high amount of resources in a relatively short period of time, it reduces the number of alternative services deployable at the same time and the opportunities for sharing the same resources in the network. Further, being based on unacknowledged transmission, streaming does not guarantee good QoS. Download and play techniques are based on acknowledged and/or forward error correction (FEC) protected download of contents. Download and play has been implemented within several technologies like multimedia broadcast multicast service (MBMS), MediaFLO and digital video broadcast handheld (DVB-H). However, these solutions arc based on the preloading of content during off peak times and require high storage space at the terminal side.

Consequently, the number of services that can he prcloaded is limited by the memory available at the terminal. Moreover, this technique does not allow deployment of content just made available to the network (e.g. the latest news video clips, or football video clips, etc.).

The present invention signals from the network to the terminals a time at which a slill-preloading audio/video content will start being played on the terminal. The signalling occurs at the service session start and communicates to the terminals a play out start time, with respect to the session start time, which occurs while the content is still preloading via broadcast channels on to the terminals. The network is able to provide this information due to the fact it knows the bit rate the content is preloaded at.

the bit rate the content will he played at on the terminals and the overall size of the audio/video content.

A detailed example is described with respect to MI3MS systems as illustrated in Fig. I and Fig. 2. Fig. I shows a typical set-up in which a broadcast multicast service centre (BM-SC) I has content br a terminal, or UE 2 which is signalled via an RNC 3.

A service session start message is delivered to the terminal including a waiting time (D) br content play out startup 4, and the content download is begun 5. The service content is preloaded on the subscribed UEs 2 via a broadcastimulticast channel using a bit rate much lower than the bit rate the content was encoded at. That is, the bit rate of the preload is much lower than the bit rate of the corresponding streaming service. The UEs 2 receiving the service must have pieviously subscribed to the service (namely the users agreed to establish a relationship with the service provider, which allows the user to receive the MBMS service as illustrated in Fig. 2). Together with the service session start niessage the network serds 4 the content play out start time 6, which is defined as the time D. measured from the session start, that the UE has to wait to start playing the audio/video content.

The er is prompted with a "service acceptance" message 7 and if service acceptance occurs within the service session duration, the content is played, beginning at the content play out start time 8 on the UE, otherwise the content will be automatically deleted once the session terminates, so not to occupy large amounts of UE memory. A content download end message 9 is sent from the BM-SC 1 to the UE 2.

As mentiord above, Fig. 2 illustrates the sequence with more than one user terminal behaving in different ways. UE 1 10 sets up a subscription with a network and subsequently UE2 11 also sets up a subscription. In this example, counting 13 for the first session equals two, as there are two UEs subscribed and at the first session start 14 download of the audio/video content 15 begins. UFI 10 sends a service acceptance 16 to accept service consumption and the audio/video content is played 17 by UE1 up to a first. session slop 18. The content starts playing while the download is still ongoing.

UE2 did not accept the service by the end of the session, so the downloaded audio/video content is deleted 19 from UE2. Counting for repetition of the first session is zero, as UE I has received the service and UE2 does not want it, so no repetition is required. The start time for content playing on the UE is determined in such a way that the audio/video sequence can play smoothly using the downloaded content. Such start time can he calculated by the BM-SC because the BM-SC knows the bit rate at which the preload will occur, the hit rate the audio/video content has been encoded at and the overall size of the content. For example, if a three minute audio/video sequence encoded at 128Kbps is preloaded on a UE at 64Kbps, the total preload time will be six minutes and the content will start playing on the UE after 3 minutes from the start of the preload. A further delay can be added to the theoretical play out start time in order to address eventual unpredicted delays in the download. The waiting time between start of the download and start of the audio/video sequence can be used for advertisements, sent to the UF in the form of MMS or as small files downloaded during off-peak times.

Content will be consunied only if the users positively reply to the service acceptance message. If the reply is negative, the content is immediately deleted in order not to occupy UE memory. This is in line with the way streaming services work i.e. the content is only available for the duration of the session and is not available once the session has ended unless the session is retransmitted. Nonetheless, this solution of the present invention has advantages over streaming because it allows consumption of the whole audio/video content if service acceptance is performed during the session duration, while in streaming mode users can consume only the content available from the time of joining the session, losing the content sent from the sesslon start to the session joining.

The present invention provides the advantage of delivering audio/video contents at lower bit rate with respect to the corresponding streaming bit rate, whilst still giving users a perceived real time experience which is not achievable with pure download and play.

The fact that the services are downloaded on broadcast channels using a lower bit rate allows more resources to be available for any alternative service (e.g. voice, data) provided by the operator at the same time and on the same radio resources. In the case of MBMS for example this feature is essential as radio resources are limited and lack of resources would cause service blockage. By contrast, streanhing delivery mode requires more resources in shorter time periods, therefore impairing deployment of alternative services in the same frequency bandwidth and during the same time intervals.

By preloading not only during off peak times, hut also immediately before the audio/video sequence play out, the preloading technique can be used for delivery of content that has just become available in the network. This still gives users the perception of a real time service, whereas download and play nde only allows content downloaded well in advance with respect to when the content will be consumed.

Therefore, download and play mode is not suitable for services related to the latest events" but only fits delivery of "old" content. The UE would not know when to start playing and conventional transport protocols do not allow for the requirement that files need to be updated whilst being consumed. One solution is to divide the content into sub files, so that the application layer only accesses sets that are complete. For example, files are fragmented into smaller sub-files that are sequentially created during the download and that are sequentially played by the application.

Claims

CLAIMS

I. A method of transferring data to a mobile device, the method coniprising broadcasting service content from a network to one or more mobile devices having a pre-existing relationship with a service provider: starting download of the content at each mobile device at a session start time: signalling a play out. start time to the mobile device: requesting acceptance of the service by the mobile device: if the service has been accepted, starting the play out on the mobile device at the predetermined play out start time; and continuing to download and play out the remainder of the session.

2. A method according to claim 1, wherein if the service has not been accepted at the end of the download, the downloaded content is deleted from the mobile device.

3. A method according to claim 1, or claim 2, wherein the play out start time is determined in the network based on preload bit rate; content encoding bit rate; and total content size.

4. A method according to any preceding claim, wherein the play out start time is signalled from the network at the session start time.

5. A method according to any preceding claim, wherein, if the service is refused at any time, the download ceases and already downloaded content is deleted.

6. A method according to any preceding claim, wherein previously stored data on the mobile device is displayed for at least pall, of the delay between the session start time and the play out start time.