WO2013093846A1

WO2013093846A1 - Method for broadcasting digital data

Info

Publication number: WO2013093846A1
Application number: PCT/IB2012/057548
Authority: WO
Inventors: Xavier Castellan; Xavier Battas
Original assignee: Quadrille Ingenierie
Priority date: 2011-12-21
Filing date: 2012-12-20
Publication date: 2013-06-27
Also published as: FR2985123A1

Abstract

The present invention relates to a method for digital broadcasting of secondary data within a primary-data transmission network (1), in particular a digital terrestrial television or satellite television network, the network comprising at least N channels and reaching at least one receiver (3) having a number T of tuners, wherein T < N. In said method, the secondary data are broken down into packets transmitted via the N channels such that the receiver (3) can, regardless of the channels tuned into, recreate the secondary data by collecting said packets.

Description

Method of broadcasting digital data

The present invention relates to the dissemination of digital data within a data transmission network.

This broadcast can be done in a digital television network, for example.

Digital television networks broadcast several types of data: primary data that corresponds to conventional television programs, and secondary data that correspond, for example, to cinema films recently released in cinemas and whose visualization requires payment by the user. additional price, similar to video on demand (VOD), or catch-up television content.

The known VOD systems use "pull" mode transmissions, digital content being broadcast at the request of users by traditional "point-to-point" transmissions between an originating system and one or more receivers.

For example, a user chooses additional digital content, referred to in what follows as "secondary data", in a catalog available from a VOD service provider and the content can be viewed by the user simultaneously with its broadcast or alternatively, be recorded in a digital storage space of the receiver and viewed later.

The invention applies more particularly to the broadcasting of secondary digital data.

In a digital television network, the primary and secondary data are broadcast on different channels, each characterized by a broadcast frequency.

The receiver retrieves the data via a network interface, called a tuner. Depending on the data it wants to recover, the tuner must listen to the corresponding frequency.

A receiver can be equipped with one or more tuners. In the case where the number of tuners is less than the number of channels, the receiver must arbitrate the use and guarantee the reception of the secondary data whatever the use of the tuners. Given that tuners are primarily tuned to frequencies that correspond to primary data, there is no guarantee that tuners will listen to channels carrying secondary data, unless they broadcast the data entirely on all channels. The cost to the operator of the transmission network would be too great.

There is a need to improve the broadcast of secondary data on a network whose receiver has fewer tuners than channels.

The invention aims to meet this need and it succeeds, according to one aspect, through a method of digital secondary data broadcast within a primary data transmission network, including a digital television network terrestrial or satellite television, the network comprising at least N channels and reaching at least one receiver having a number T of tuners, with T <N, the method in which the secondary data is decomposed into packets transmitted on the N channels of so that the receiver can, regardless of the channels listened, reconstitute, by collecting said packets, the secondary data.

Thanks to the invention, it is not necessary to transmit the set of secondary data on each channel. Bandwidth can be preserved.

The number of tuners T may be equal to 2. The invention is however not limited to a particular number of tuners.

The data transmission network is for example the digital terrestrial television (DTT) network or the satellite television network. The data transmission network can be unidirectional. The invention makes it possible to overcome a return path, if desired.

The transmission network may include a transmitting system.

For each secondary data block, N packets can be generated, so that any T packets received on N, the original secondary data block can be reconstructed.

Packets can be generated by a packet generator receiving the secondary data stream. The methods used by the packet generator include methods based on error correcting codes. From P secondary data packets, called "source packets", the packet generator can generate N-P correction packets. If the generator receives P packets, N packets come out. Of these N packets, P are source packets and NP are correction packets. A packet can have a size between 1 / T and 1 times the size of the secondary data from which it comes.

Secondary data packets can be sent simultaneously on all channels.

The transmission of the N secondary data packets on the N channels takes place randomly, so that a receiver which receives T packets can receive all the T source packets.

The secondary data can be reconstructed within the receiver with a rate less than N times the data rate of the secondary data transmission.

The secondary data can be stored locally on the receiver, and simultaneously on all the receivers that listen to that channel.

The reconstruction of the secondary data from the packets collected on the same channel can be done with a flow rate of between 1 / T and once the rate of flow with which the secondary data is received by the packet generator.

The dissemination of the secondary data can be performed independently of a request from a user to obtain the secondary data in return, in particular independently of a request for example to obtain the secondary data before a predefined date or within a time limit to from the issue of the request less than one or more days, including one or more hours, including one hour.

The receiver has a digital storage space, for example hard disk or static memory, and the secondary data may include data relating inter alia to the fraction of the storage space allocated to the secondary data recording, which allows that the distribution of the storage space of the receiver is managed from the transmitting system. The receiver may be configured to be remotely controlled by receiver operation control data included in the secondary data.

The secondary data may include data relating to its management by the receiver and at least a portion of the secondary data may be recorded or erased from the digital storage space of the receiver according to said data, thereby allowing management of the recorded secondary data. in the receiver's storage space by the transmitting system. The transmitter system performs for example updates of the secondary data stored in the storage space of each receiver. This allows for example to remove from the list of the oldest searchable files to make room for new.

The secondary data may include media files, including movies or video clips, for example as part of a use for VOD.

The secondary data sent is for example a multilingual content, which may allow this content to be transmitted only once regardless of the language of the user. This is interesting especially in the case of the satellite television network.

The secondary data transmitted to a user may be encrypted, for example recorded on the receiver according to a receiver-specific encryption key.

Secondary data can be broadcast independently of the Internet. The invention can thus make it possible to overcome the use of the Internet network.

The receiver comprises for example a TV output, including a composite video type connector or SVideo, HDMI or other digital output.

According to another of its aspects, the subject of the invention is also a secondary digital data broadcasting system of at least N channels to at least one receiver having a number T of tuners, with T <N, in a primary data transmission network,

the broadcast system comprising a packet generator arranged to decompose the secondary data packets transmitted on the N channels so that the receiver can, regardless of the channels listened and collecting said packets, reconstruct the secondary data.

Such a system can take up all or part of the characteristics of the diffusion method defined above.

Another subject of the invention, according to another of its aspects, is a packet-decomposed secondary data receiver in a transmission network comprising N channels, in particular a digital television or satellite television network. the receiver having a number T of tuners each listening on a channel, with T <N, and reconstructing the secondary data from the packets transmitted simultaneously on the N channels.

If the T packets received by the T tuners are source packets, the receiver gets the secondary data directly, without the need to reconstruct the data. In the opposite case, the T received packets being a mixture of source packets and correction packets, the receiver reconstructs the source packets from said T packets received.

Such a receiver can recover all or part of the characteristics of the diffusion method defined above.

The receiver can include a secondary data storage space.

The receiver can be integrated in a television or in a decoder, for example.

The invention will be better understood on reading the following description, non-limiting examples of implementation thereof, and on examining the appended drawing, in which:

FIG. 1 schematically represents an example of a data transmission network according to the invention,

FIG. 2A represents a step of the diffusion process according to the invention, and

FIG. 2B represents a second step of the diffusion method according to the invention.

There is shown in Figure 1 a data transmission network 1 according to an exemplary implementation of the invention. This network is for example a network of digital terrestrial television (DTT) or satellite television. The network 1 is preferably a multichannel and unidirectional network.

The transmission network 1 comprises a transmitter system 2, a plurality of receivers 3, only one of which is shown, and a plurality of transmission channels 11, 12, 13 and 14 on which the transmitter system 2 transmits. In the example illustrated, the number N of channels is equal to four, but the invention is not limited to a particular number of channels. Primary data is transmitted by the transmission network 1 through the channels 11, 12, 13 and 14, for example television channel programs, and secondary data is also transmitted. These secondary data comprise, for example, multimedia files such as films for which the display is paying, such files having, for example, multilingual contents.

The secondary data also comprise, in the example described, data relating to the management of their content by the receiver 3, the reception of these data by the receiver causing for example a recording or erasure in a storage space of the receiver 3 depending said data. Descriptive data are for example associated with each secondary data file, this data comprising for example, when the file is a film, the title, the genre, the author, the actors, a production date, a summary, the language , or a start date and / or end-of-life date of the file beyond which it will for example be deleted from the storage space of the receiver 3.

A parameter defining the maximum number of readings of a file can also be associated with this file.

The secondary data are preferably transmitted in an encrypted manner, and the recording may implement local encryption, consisting for example of encrypting a file with a specific encryption key to each receiver, as for example described in patent FR 2 846 831.

The transmitter system 2 is in the example described a service provider, for example a television channel or any operator providing video on demand.

The transmitter system 2 comprises a packet generator 5, which will be described in more detail below.

The receiver 3 comprises two or more tuners, permanently lit, and an internal or external hard disk or other mass memory defining a digital storage space 4 with a capacity for example between 160 GB and 250 GB, this range n ' being not limiting.

The receiver 3 can deliver the useful signal in the form of digital or analog video signals, for example via an HDMI connector.

The receiver 3 is for example integrated with a television or is in the form of separate housing. A fraction of the digital storage space 4 is dedicated to the recording of the secondary data, this fraction being able to vary according to the receiver 3.

The receiver 3 may comprise a user interface, not shown, for example comprising means for displaying a list of files from the secondary data received and means for modifying parameters relating to the reception of these data and / or for selecting files so received.

The user interface may comprise for example a screen and a keyboard. The screen is for example the one with which programs are displayed or is present on the remote control. The keyboard is for example office remote control. Alternatively, the user interface may include voice recognition means.

The user of the receiver 3 can, through the user interface, view all or part of the files available in the storage space 4 of the receiver 3 as well as data relating to the management of each secondary data file. These management data can allow daily management of files broadcast by the transmission network, for example a daily management, at a set time, files. The receiver 3 comprises for example a processing unit, not shown, for example comprising one or more electronic cards and configured to erase the files whose end-of-life date is exceeded or the oldest files recorded and n ' for example have not been viewed for a predetermined duration.

The content management data may still cause the files stored in the digital storage space 4 of the receiver 3 to be completely erased.

The user can for example act on the user interface of the receiver 3 to change the language of a received file. The user interface can also be configured to allow a user to view a received file, a banner showing the user the file number and an identifier that the latter will have to transmit to a service center, for example via a voice server. interactive, to obtain the viewing rights of the file, being for example displayed on the screen of the user interface.

At the end of the transmission of a multimedia file, the transmitting system 2 can transmit a new multimedia file to the receivers 3. In a variant, the sending system 2 can broadcast again the same secondary data in the network of transmission, for example again the same file, depending on service quality objectives to achieve, technical constraints and / or topology of the transmission network, for example the notion of packet loss. As a variant, once a certain number of secondary data have been broadcast, the transmitter system 2 can go on standby.

The receiver 3 comprises in the example illustrated in FIG. 1 two tuners 21 and

22, the invention is however not limited to a particular number of tuners.

The number T of tuners of the receiver 3 is smaller than the number N of channels of the transmission network 1.

In the example described, the receiver 3 comprises a packet regenerator 6, for example an electronic card comprising a microprocessor arranged to execute a program making it possible to regenerate the packets from the secondary data.

In an exemplary implementation of the broadcasting method according to the invention, as illustrated in FIG. 2A, the sending system 2 seeks to transmit three blocks Pi, P ₂ and P ₃ of secondary data, corresponding to all or part of a multimedia file.

These blocks are received by the packet generator 5, which breaks down each block Pi (i = 1, 2 or 3) of secondary data into as many packets as the transmission network 1 comprises channels, or in the example described in four Pi_ooi packages, P _2-

The pi blocks of secondary data are decomposed into packets so that the receiver can, regardless of the channels being listened to and after collection of the packets, completely reconstruct the secondary data blocks.

The methods used by the packet generator to break down the blocks Pi of secondary data into packets include methods based on error correcting codes. The generation of so-called "correction" packets is operated in a known manner with error correcting codes.

A packet can have a size between 1 / T and 1 times the size of a block Pi of secondary data.

The Pi_ooi, Pi-oo ₂ and Pi_oo ₃ packets are transmitted to the receiver 3 on the channel 1 1, the packets P ₂ _ooi, P ₂ -oo ₂ and P ₂ _oo ₃ are transmitted on the channel 12, the packets P ₃ _ooi, P ₃ -oo ₂ and P ₃ _oo ₃ are transmitted on the channel 13 and the packets P4-001, P ₄ -oo ₂ and P ₄ _oo ₃ are transmitted on the channel 14.

The transmission of the secondary data packets is carried out randomly on each channel 1 1, 12, 13 and 14. Since the receiver 3 is configured to listen at the same time as a number T of channels for each block Pi of secondary data, corresponding to the number T of tuners, only two out of four packets are collected in the example illustrated for each block Pi secondary data, for example the P _1-001 and P ₂ _ooi packets for the PI block, the P ₂ _oo ₂ and P3-002 packets for the P ₂ block, and the P2-003 and P4-003 packets for the block P ₃ . These packets are managed by the packet regenerator 6.

Thanks to the decomposition method used by the packet generator 5, the three blocks Pi, P ₂ and P ₃ of secondary data are fully reconstructed and, for example, locally recorded in the storage space 4 of the receiver 3 for the user. However, the pi blocks of secondary data are reconstituted within the receiver 3 with a bit rate lower than the bit rate of the secondary data blocks at the time of transmission, notably less than four times this bit rate. The reconstruction of the pi blocks of secondary data from the packets collected on the same channel is thus carried out with a flow rate lower than that of the flow with which the pi blocks of secondary data are received from the packet generator 5.

The invention is not limited to the examples which have just been described.

The expression "having one" shall be understood as being synonymous with "having at least one", unless the opposite is specified.

Claims

A method of digital broadcasting of secondary data within a transmission network (1) of primary data, in particular a digital terrestrial television network or satellite television network, the network comprising at least N channels and reaching at least one receiver (3) having a number T of tuners, with T <N, a method in which the secondary data is decomposed into packets transmitted on the N channels so that the receiver (3) can, whatever the channels being listened to, reconstitute, by collecting said packets, the secondary data.

2. Method according to claim 1, secondary data packets being transmitted simultaneously on all channels.

3. Method according to one of claims 1 or 2, the transmission of secondary data packets being performed redundantly on each channel.

4. Method according to any one of the preceding claims, the number T of tuners being equal to 2.

5. Method according to any one of the preceding claims, the data transmission network (1) being unidirectional.

6. Method according to any one of the preceding claims, the secondary data being reconstituted within the receiver (3) with a flow rate less than N times the flow rate of the secondary data transmission.

7. Method according to any one of the preceding claims, the secondary data being recorded locally on the receiver (3).

The method of any of the preceding claims, wherein the packets are generated by a packet generator (5) receiving the secondary data stream.

The method of claim 8, reconstructing the secondary data from the packets collected on the same channel performing with a flow rate of between 1 / T and once the flow rate of the stream with which the secondary data is received by the packet generator (5).

10. System for the secondary digital data broadcasting of at least N channels to at least one receiver (3) having a number T of tuners, with T <N, in a transmission network (1) of primary data, the broadcast system comprising a packet generator (5) arranged to decompose the secondary data into packets transmitted on the N channels so that the receiver (3) can, regardless of the channels being listened to and by collecting said packets, reconstruct the secondary data.

11. Receiver (3) of secondary data broken down into packets, in a transmission network (1) having N channels,

the receiver having a number T of tuners each listening on a channel, with T <N, and reconstructing the secondary data from packets transmitted simultaneously on the N channels.