FI99065C - Processing a program file in a digital broadcasting system - Google Patents

Description

99065

The present invention relates to the processing of program information of service programs 5 in a digital broadcasting system, which enables the transmission of audio and data services and the selective reception of these services. The information transmitted on the transmission channel can be either a continuous audio or data stream or in packet form.

10 In the digital audio system DAB (Digital Audio Broadcasting) developed for the efficient use of frequency bands, the transmission path is fully digital and the system is intended to replace the current commonly used analogue frequency modulation radio-15 radio. The DAB is specially designed for a mobile environment, i.e. the receiver can be in motion and nevertheless various attenuations and disturbances in the propagation of the radio signal are avoided by the combined effect of suitable modulation and channel coding.

20 The DAB defines a multi-carrier digital radio channel suitable for transmitting both audio and data services. The fully digital transmission channel can be either a continuous data stream or a packet channel. The DAB system for transmission, transmission and reception ··· 25 has been described in detail in ETSI (European • · · · 1

Telecommunication Standards Institute) in ETS

• m · 300 401, February 1995.

«· · From the user's point of view, the DAB system has the highest .. level of abstraction called ensemble, Figure 1. It contains • · • t» 30 all the services that are in a given frequency band. The change of ensemble takes place by tuning to the second frequency band, just like channel selection in the current FM radio reception. The ensemble is divided into services, in the figure Alpha Radio 1, Beta Radio and Alpha 35 Radio 2 as an example. In addition, there may be data services, although they are not shown in the figure 299065. Each service is further divided into service components. Each service component is either an audio channel or a data channel. For comparison, the FM radio has only one service and one service component (audio / speech) on each channel. At the lowest level, there is a transmission frame with a duration of exactly 24 ms or 96 ms, depending on the mode, consisting of three parts that are consecutive in time. The first is the synchronization channel, which does not contain service information. Next 10 is a Fast Information Channel (FIC), which is a fixed length per mode. The last is the MSC (Main Service Channel) which contains all the subchannels. The location, size, and number of subchannels within the MSC may vary, but the size of the MSC is fixed. The MSC contains up to 63 different audio and / or data subchannels. The subchannels are numbered so-called. Based on Subchannel ID from 0 to 62. In addition, the MSC may have an Auxiliary Information Channel (AIC) with a fixed channel number 63. The AIC 20 may contain the same type of information as the FIC.

Reference is made to Figure 2, which shows a simplified DAB system. At the transmitting end, the transmission control device 1 controls the transmission. FIC and control block 2 provide general information about audio and data services *: 1 25 SI (Service Information), which facilitates the user to transmit the desired service, multiplexing configuration information • MCI (Multiplex Configuration Information) that is, information about the number, size, and location of the subchannels .. ^ and conditional access information CA (Condi- * ... 30 tional Access), which may be a charge for the services. «· · • · · ·. tea / encryption information. Together these and

* 'possibly in addition to the high speed information data channel FIDC

form a Fast Information Channel (FIC). The audio information 35 provided by the audio service providers 3, e.g. music, is compressed in the MPEG-3 99065 encoder 4 and fed to the audio channel encoders 5. Correspondingly, the data provided by the data service providers 6 are encoded in the data channel encoders 7. The data can be transmitted in stream mode or addressable pa-5 chains. one subchannel may contain several packet channels.

The channel-encoded and time-interleaved data and audio information as well as the FIC information are fed to block 8, where the different channels are first multiplexed into a common frame. The frame is then divided into blocks, and on a channel-by-channel basis, successive OFDM symbols of a certain duration are formed, which are modulated by the D-QPSK (Differential Quaternary Phase Shift Keying) method. An inverse Fourier transform is then performed, resulting in a time domain I / Q signal that is used to modulate the radio frequency carrier. Each transmission frame is thus time-multiplexed between a synchronization channel, a high-speed information channel FIC, and a channel MSC (Main Service Channel) containing audio and data services.

20 DAB mode III for terrestrial, satellite and cable transmissions has 192 carriers, a frame with 153 symbols and a frame duration of 24 ms.

At the receiving end, the received DAB ensemble is decoded in a COFDM (Coded Orthogonal Frequency Division Multifunction 25 block) block 9, which converts the I-Q signal into a digital format. The digitized signal is shifted to the frequency • * · · level by fast Fourier transform, the de-interleaving is removed, and the transmission frames are formed from successive • * t OFDM symbols. The formed transmission frame is thus as shown in the lower part of Fig. 1. Information • · · • · ·

*. channel FIC and channel MSC containing audio and data services

«Subchannels are separated from each other and subchannels are separated from the MSC channel and they are channel decoded in decoders 5 'and 6'. The desired subchannels are then routed for further processing.

35 The subscriber learns from the received FIC channel which 4 99065 services are included in the received ensemble and can choose the desired service or services accordingly.

Figure 3 shows a receiver suitable for media applications. As previously described, the received ensemble and -5 are fed into several services and each service further into service components. The service component is either an audio channel or a data channel. The entity is decoded in COFDM (Coded Orthogonal Frequency Division Multiplex) block 31 and in demultiplexing 10 the subchannels SUBCH1, ..., SUBCHL and the fast information channel FIC components SI, MCI and FIDC are separated from the MSC channel. There are a maximum of 64 subchannels. The desired subchannels are then routed for further processing. The desired packet channel can thus be distinguished from the data channel on the basis of the packet address and routed to the receiver. By combining subchannel service components such as audio / speech, continuous video and packet data according to the application program, multimedia services, a hypermedia service, a file-based service and hypertext are formed. The generated services 20 are then taken to the user's display device or further processed. Interface A is the interface of the service components, after which the user agents form the desired services from the service components.

25 In practice, the DAB receiver can distinguish between: service information processing block (SI Handler), inf or- • · · ·; * · *; a data channel processing block (FIC Handler) to which the FIC channel is routed, and an application program block (Application; ·. Software Block) to which the information channel processing block • · «'... 30 FICH provides information on the location of the subchannels in the multiplex.

• · · *. The service information processing block, to which both the service information channel S1 and the backup channel for information AIC are fed, provides the application program block with more detailed service description information, which in turn generates for the user e.g. a graphical user interface. For example, the user interface may contain text that reads "this Ensemble (name) has services ALPHA RADIO 1, BETA RADIO, ALPHA RADIO 2" followed by the prompt "select service". The user then selects the desired service by typing, using the mouse or in another suitable way, after which a list of what programs this service contains and possibly also a short description of the programs is displayed. In the description, it can be indicated that it is possible for the user to choose whether the 10 wants to view e.g. images related to music or lyrics of songs on the screen. The user thus makes several choices in order to obtain such a program and in the form he wishes. In response to user selections, the application program block instructs the information channel processing block to separate the desired channels from the subchannels to form a program.

The problem with this type of selection is that the application program processing block has to operate in a service hierarchy and on the rather scarce information about the program content that is obtained from the prior art service information channel S1 and the information spare channel power AIC. Therefore, the selection of the service components required to form the desired program requires numerous actions from the user. Exploring the program offerings takes time, because sometimes you have to go back to the • ensemble level or service level in the hierarchy and move forward, making choices again down the hierarchy. In the prior art system, the information transmitted to the user on the FIC channel is only the name of the service represented by the 16-character "service la- · · 30 bel". Names are sent as a 6 • · · * · ’bit-encoded binary number.

t

As a general solution to the problem, it has been proposed in the art to utilize the rather large data transmission capacity of the system by sending a special "electronic program guide" to the receiver. It would be, for example, a text file 6 99065 to which speaks plainly about the various services offered. The format of the file and the channel on which it would be transmitted are not shown in more detail. In form, it could resemble the Radio and TV Programs page currently published in Sanoma-5.

It is therefore an object of the present invention to provide a guidance arrangement which facilitates the user to make choices between the numerous programs included in the DAB ensemble. The guidance should be graphical, easy to use, informative and interactive. The internal structure of the tutorial should be such that the user is able to start the desired program directly from the tutorial.

It is also an object to provide an arrangement which is suitable not only for transmitting an electronic program guide but also for transmitting any file of the same type as the program guide. An example of such use is an interactive multimedia-type tutorial.

The set object is achieved by the system described in claim 1 and the receiver described in claim 6.

According to the invention, a special file is created and transmitted at the transmission end of the DAB system. It is a ·; · 25 plain language file that could contain images and. text. Each service provider can create their own file. The operator either collects the different files, combines them «', and edits them into a single file to be sent, or preferably, the operator makes its own file containing I i * it * 30 links to the files of the service providers. According to the basic idea of the invention, the file contains text and images to be displayed to the user, as well as a wealth of information invisible to the user, intended for the application program of the receiver. The information can be hidden text, instructions, algorithm-35 and. The most important information invisible to the user is a link that, by activating 7 99065 users, links a file to another file. In this case, by activating the links, the user is able to navigate in the files and quickly retrieve and collect the information of interest to him, after which the receiver 5 automatically assembles the desired service from the subchannels of the DAB multiplex. In particular, an electronic program guide can be formed from the above.

According to a particularly preferred embodiment, the file consists of HTML image pages. Image pages can be broadcast on one channel or divided into multiple channels.

The invention will now be described in more detail with reference to the accompanying figures, in which Figure 1 shows the hierarchical levels of a DAB system, Figure 2 shows in a reduced form the DAB system as a whole, Figure 3 shows operations at the receiver and Figure 4 is a schematic diagram of the invention.

In order for the user to get the most out of the invention, it is assumed that he has at his disposal a sufficiently large display device for displaying a sufficiently large amount of information at a time. This requirement can be met by connecting the «• J · DAB receiver to a PC.

* i »ti I According to the invention, each service provider compiles its own service guide using the same uniform t \ format. Particularly preferably, the format is HTML (Hypertext Markup Language) known per se, which is a simple data format for creating hyper- • · · • text documents and producing documents to be transferred from one hardware to another.

In order to understand the invention, the content of the HTML concept will be briefly described below. HTML documents are 8 99065 SGML documents and their general meaning theory allows the presentation of different types of information. The source material of the service provider, which can be text, images or combinations of text and image or structured documents containing graphics, is converted to HTML using HTML. The document is sent via a transmission network to the recipient's computer, whose software converts the received document to be displayed on a screen in the layout specified in the document. SGML is defined in ISO 8879: 1986, Standard Generalized Markup Language (SMGL) for Information Processing Text and Office Systems. One known area of application is the World Wide Web (WWW), a hypertext-based distributed information system developed by CERN. Its use is especially known for its Internet connection.

The term HTML is commonly used to refer to both a document type and its events. Events refer to changes in elements in a document, such as the beginning and end of a title, the beginning and end of a paragraph, images, hyperlinks, etc. Markups are syntax delimiters added to document data to describe its structure. The most common markup is a tag used to separate elements, such as .. ^ 25 start tag, which is the <character, and end tag, which is the </. Tags can also be used to instruct the receiver's program, for example, the <TITLE> element indicates that the next incoming text is a title, which in turn ends with the • ·· 'element </TITLE>. An important element for the present invention is the anchor <A>. It specifies a hyperlink that • ·! Is the relationship between two anchors. The anchors can be in the same or different documents. This is what makes Internet surfing familiar to Internet users possible. In order for a user to move from an anchor over a link to another 35 anchors, a Uniform Resource Identifier (URI) must be defined, which is used to uniquely identify hyperlink anchors. In practice, the URI consists of a URL (Uniform Resource Locator) and a Relative URL. The link can refer either directly to target 5 (head Anchor) using the URI or indirectly using the URL.

Referring to Figure 4, each DAB service provider creates an HTML format guide file associated with its service, comprising one or more pages. File 10 may contain portions of text and images. One page may have an overview of the service, the other page may have a more detailed presentation of the day's program with showtimes, and the other pages may have a weekly program. Some pages may have subtitles for the 15 words of the music being played. In addition, there may be image files that contain still images. A page can have several links that point to specific points on other pages of the same file or to an image file, i.e. the link is associated with the destination (head) URL.

20 A DAB operator, which may also be referred to as a multiplex provider, compiles the HTML program files of the various service providers and possibly adds its own hyperlinks to them. In addition, the operator makes its own file, which introduces the possible different ensembles and 11 ’25 lists their services and adds hyperlinks • · *. service provider files. Hyperlinks can be added to the page of the service provider's program file, which is an overview of the service: ··: bones, to link the pages of other service providers or other services of the same provider. to pages (horizontal • · j linking in the DAB hierarchy) and where pages can be linked to an ensemble (vertical linking in the DAB hierarchy). In this way, the DAB operator generates a combined program guide that contains several pages of HTML files.

35 An excerpt from the service provider's program guide 10 99065 could be, for example, as follows:

Alpha Radio: This service consists mainly of music with occasional news. The programs today are.

8:00 - 9:00 Light music to start the working day.

5 This is a multimedia program. You may view the program with all the multimedia features by clicking here or you may choose to only listen to the program with lyrics or without lyrics.

9:00 - 9:10 News 10 •

If you want to preview the Alpha Radio programs Tomorrow click Here.

The 15 points shown in bold in the above section are hyperlinks. In HTML, they have a <A> tag next to them. When the user clicks on such a point, the application program retrieves the anchor address of the other end of the link and performs a jump to the file and point provided by it, at which point a new page appears on the screen. Thus, when the user 20 wants to watch tomorrow's program, he clicks the mouse at the last bold point in the snippet, whereupon the application program retrieves the program page for that day. The service provider is free to make their own pages 1 and add hyperlinks to them, making it possible to ‘1 * 1 25 give the user as detailed information about the programs as needed.

••• ί Bold text Alpha Radio can be a link to the list of en- • · ί semble services, which can be a link to • · · · further to the list of other ensembles. In the previous case, by clicking on the desired service, the user sees the supply of channels in this service.

Once the DAB operator has generated its own pages and merged the program pages of the service providers, this is ·; ·; a combined program guide consisting of successive HTML files is placed in the multiplex. At least 11,99065 sections, most preferably the landing page, are placed. An AIC (Auxiliary Information Channel) with a fixed channel number of 63. Other files can be placed either in the AIC or in a packet channel.

5 The application program on the receiver, which may be located on a PC, generates HTML pages from the received files and generates for the user a graphical user interface defined by them, in which hyperlinks are displayed. They allow the user to switch to the service they want. The application program block searches for a hyperlink activated by the user based on its anchor address and displays the file containing the anchor. Files are downloaded and launched immediately in response to user intervention.

15 The above does not require major changes to the DAB system: mechanisms are needed to create HTML files at the sending end and to process them at the receiving end. Such mechanisms are familiar to a person skilled in the art, e.g. from an Internet connection. In addition, mechanisms are needed for transmitting groups of files on the packet channel so that the receiver can assemble the correct files in the correct order. In addition, it is necessary: a mechanism by which the startup file, in this case the first page of the program file, is notified. . For 25 takers. These mechanisms related to file transfer are described in the patent application FI-954752 filed by the applicant at the same time as this application.

·: · The only thing that requires a more precise definition of em.

in addition to the transfer of files 30 disclosed in said patent application, there is a reference mechanism for DAB-Ensemble resources, i.e. programs, files, etc. In this case, the meaning of URLs (Uniform Resource Locators) must be specified.

in hyperlink anchors. Some embodiments concerning the audio service, the packet mode, the high-speed data information channel FIDC included in the FIC-35 channel are shown below.

12 99065 and finally the information backup channel AIC.

The following URL is suggested for the audio channel: dab: // ensemble_id / service_id: 16 / subch_id: A, where 5 ensemble_id is the Ensemble identifier as a decimal number, service_id is the service identifier as a decimal,: 16 means that a 16-bit service identifier is used, subch_id is the subchannel identifier of the service component and: A means that the service component is a continuous 10 audio streams. When this queue is presented to the receiver, audio reception is started immediately. Note that all service_ids and symbol_ids in this queue are completely invisible to the user.

If you only want to separate 15 audio files of a certain length from the previous audio stream (a certain time of music), add fields / start_främe: length to the end of the previous ULR, which creates a file of frames and becomes dab: // ensemble_id / service_id: 16 / subch_id: A / start_främe : length, 20 where start_frame is the starting frame from which the count starts and length = the length of the audio files as logical frames in the decimal system. When this queue is presented to the receiver, it extracts the desired frames and stores them as a file in memory.

• ·. 25 To start the XPAD application, use the ··· anchor: • * · ·:. dab: // ensemble id // service id: 16 / subch id application type, • «· 1” ~ where entry_type is the application type number • ♦ · in decimal.

30 The number following the subchannel identifier indicates • • • * "that the TMID of the service component refers to continuous audio.

• · ·

If the user wants to start at the same time both XPAD

application for that audio service, the following queue can be used: 35 dab: // ensemble_id / service id: 16 / subch id: A / application_type 13 99065

To receive a file from XPAD, you can use either the string dab: // ensemble_idlservice_id: 16 / subch_id: P / filename or the queue

5 dab: // ensemble_id / service id: 16 / subch_id: P / file_id: I

In the queues, the symbol P indicates that this is the audio channel XPAD. According to the specification, PAD (Program Associated Data) means a piece of data attached to the end of an audio frame, in which, for example, the words of a song can be transferred.

10 Such a space is created when compressing the frame.

XPAD means that it is a so-called extraPAD. The filename is the name of the XPAD file with any extensions, the N indicates that the file name is referenced, / file_id is the file extension in decimal-15, and the I indicates that the file is referenced using its extension.

It is assumed above that a communication protocol is defined in the PAD and the application type conveying the protocol is implicitly known.

20 The following are possible for the receiver

URL strings to display when the link refers to a packet channel. dab: // ensemble_id / service_id: 16 / scid: D / subserv: s / filename: N,, dab: // ensemble_id / service_id: 32 / scid: D / subserv: s / file_id: I

where scid is the identifier of the service component in the decimal system,: D indicates the reference to the identifier of the service component, · sub: is the path of the identifier in decimal .. * · * kuna,: S indicates that the path identifier is being referenced.

::: Placing the / subservtS field in the URL is optional.

: * · *: Queue: 32 indicates that a 32-bit service identifier is used.

The FXC data channel FIDC can be referenced using a URL

• · · * ·: ·, of type dab: // ensemble_id / service_idz 16 / fidc_id: F, where fidc_id is the FIDC channel identifier in the decimal system and the notation: F means that the FIDC channel: 35 identifier is referenced.

The information backup channel AIC differs from other packet channels in that 99065 in most cases only the operator provides information for this channel, not the service provider. Therefore, the following URL does not contain a service identifier: dab: // ensemble_id: A / subserv: s / filename; N 5 dah: // ensemble_id: A / subserv: s / file_id: l

Note: A refers to subchannel 63 and AIC channel packet address 1023. The directory path subserv is optional.

A hyperlink to Alpha Radio is mentioned in the program guide of the service provider mentioned at the beginning of the special part of the application. When presented in HTML format invisible to the user, the link would be in the format <A HREF="dab://5/12:16/5:D/4:S/alpharad.jpg:N"> Alpha Radio </A> The URL refers to a packet channel where is a jpeg image file-15 with the nickname 'alpharadjpg'. The ensemble identifier is 5. and the 16-bit service identifier is 12. The service component identifier is 5 (this component contains jpeg images in the example case). The subservice identifier (directory path identifier) is 4. It is not necessary for the receiver to specify that the image is a jpeg image only because the identifier is jpg. This information is also included in the IDG file type parameter.

The next hyperlink in said snippet is multimedia features by clicking here, which would be html; * 25 formats: «<A HREF="dab://5/12 :16/7 :D/startup.mhg:N"> multimedia features; by clicking here </A> • · · · This URL refers to an MHEG file named boot.mhg on the packet channel. When you download this file, the 30 MHEG program takes responsibility for the multimedia presentation. In- • · · * ... IDG file type-pa- of the data group conveying the format. the parameter indicates that this is a multimedia startup file in MHEG format. Based on this, the receiver can i: transfer control to the MHEG program.

35 The following hyperlink in the snippet is with lyrics.

15 99065 In HTML format it is <A HREF="dab://5/12:16/23:A4"> with lyrics </A>. In it, the URL refers to the audio stream of subchannel 23. Application type 4, which is ITTS text, is launched alongside the audio stream. After this, the snippet will contain 5 hyperlinks without lyrics. In HTML format, it is <A HREF="dab://5/12:16/23:A"> without lyrics </A>.

The last hyperlink in the snippet is here and in HTML format it would be <A HREF="dab://5:A/alphara2.htm"> here / A>. Anchor URL 10 refers to an HTML file called alphara2.htm. The file can be found on the AIC channel.

The foregoing description and the accompanying drawings are intended to illustrate the invention only. Various variations and modifications of the invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention as set forth in the appended claims.

• 1 • · · • · · • · · 1 • · · · · 1 • · · · · • • • • · · · • • • · · · · · · ·

Claims (11)

16 99065 A digital broadcasting system, wherein a transmission frame formed by orthogonal frequency multiplexing OFDM comprises, in time-multiplexed: a high-speed information channel including general information about audio and data services, multiplexing information indicating the number, size and location of subchannels, and multiplexing information and a data services channel, wherein one subchannel is a backup channel for information, characterized in that a hypertext text type program is combined in the transmission frames from a plurality of separate plaintext files, the files of which contain information invisible to the user that can be activated by the user. System according to Claim 1, characterized in that the program is the Ensemble's electronic program guide. A system according to claim 2, characterized in that the separate plain language file is a hypertext type program with text and images created by each service provider, containing text and images, and in that the system administrator adds its own files. ♦ .... 4. A system according to claim 1, characterized in that the program is transmitted on a high-speed • «· • · · • information data channel (AIC). A system according to claim 1, characterized in that part of the program is transmitted! ;: on the high speed information data channel (AIC) and the rest on the subchannel transmitting the packet data of the service provider. A system according to claim 1, characterized in that the separate plaintext file is a file of the HTML (Hypertext Markup Language) type, which may comprise several pages with links. 7. A receiver of a digital broadcasting system, wherein general information (SI) for audio and data services, multiplex configuration information (MCI) indicating the number, size and location of subchannels, and a fast information data channel (FID) are separated from a received high-speed information channel (FIC) of a transmitted transmission frame. 10 subchannels are separated from the channel providing audio and data services, one of which is an information backup channel (AIC), characterized in that the receiver has means for separating and displaying a program transmitted on at least one channel of the transmission frame on a display device combined from several separate plain language files. in addition to information invisible to the user which can be activated by the user, the user selects the desired service on the basis of the information displayed on the display device by activating the invisible information on the basis of which said means form prompt in response to the receiver car; · 'Mathematically separate the subchannels containing the service components of the selected service to implement the service. ‘· 25 Receiver according to Claim 7, characterized in that the «« ·· program files processed by the receiver are HTML (Hypertext Markup Language) • M · type files. Receiver according to Claim 7, characterized in that the service-specific program of each service provider is displayed on the display device in its own way. A receiver according to claim 7, characterized in that it separates at least a part of the program 35 from a subchannel which is a spare channel (AIC) for information. 18 99065 Receiver according to Claim 7, characterized in that the program is an electronic program guide for the ensemble's audio and data services. »*« • · * • * · ♦ • * · f · · ♦ * · «•« * • · • · · · M4 • · · * «M4 • · · *« · i: 19 99065