GB2369276A

GB2369276A - Enabling a user to select, for display, a subset of the total additional information contained in a DAB radio broadcast

Info

Publication number: GB2369276A
Application number: GB0118704A
Authority: GB
Inventors: Maik Scholz; Arnd Wendland
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2000-08-11
Filing date: 2001-07-31
Publication date: 2002-05-22
Anticipated expiration: 2021-07-31
Also published as: FR2812989A1; DE10039234B4; GB2369276B; DE10039234A1; GB0118704D0; FR2812989B1

Abstract

DAB radio broadcasts include audio signals in the form of radio programmes, and additional textual information such as programme type codes (PTY) and an indication of whether a program provides traffic information. The present invention is concerned with the construction of a data filter to select only additional information which has the features specified by a user. Based on user input at the head end unit (1) a Create Filter() message is generated and sent along a bus to a receiver unit (3). The Create Filter() message specifies at least some of the selected additional information. In response, the receiver unit generates the data filter and returns a filter identification number to the head end unit. The filter can be extended by sending an Add Filter () message specifying further selected additional information, together with the identification number of the original filter. The identification number is also used in Delete Filter () messages to specify which filter should be deleted.

Description

DESCRIPTION

METHOD OF FILTERING DATA TRANSMITTED

BETWEEN A DISPLAY AND AT LEAST ONE DATA SOURCE

DATA SOURCE AND DISPLAY

The invention concerns a method of filtering data transmitted between a display and at least one data source and/or a data source and/or a display.

It is already known for a DAB (digital audio broadcasting) box to be connected by an interface to a so-called head unit, wherein the head unit serves as a display and allows program tuning etc. to be effected by a user.

In accordance with a first aspect of the present invention there is provided a method of filtering data transmitted between a display and at least one data source, wherein the display requests data from a list of the at least one data source, the requested data are filtered by a data filter, the display transmits a first message to the at least one data source, and wherein the at least one data source through evaluation of the first message generates the data filter, and the at least one data source assigns an identification to the data filter and communicates the identification to the display.

In accordance with a second aspect of the present invention there is provided a data source comprising a memory for data, a first processor for processing the data, and means of transmitting the data to a display, the first processor comprising means of generating, extending and deleting a data filter for the data and the data source comprising means for receiving messages from the display, the messages indicating whether the data filter is to be generated or extended or deleted.

In accordance with a third aspect of the present invention there is provided a display comprising a display panel for displaying data, a second processor for processing the data and means for receiving the data, wherein the display comprises means for generating and transmitting messages, the messages indicating whether a data filter in a data source is generated, extended or deleted.

In contrast to the prior art, the method according to the invention of filtering

data transmitted between a display and at least one data source andlor the data source according to the invention and/or the display according to the invention has the advantage that for lists, which frequently occur during a communication between a display and a data source, a data filter for sorting and/or restricting list elements as the data is generated, wherein an identification is assigned to said data filter. This has the advantage that the required messages in the form of interface commands for processing the data filter are only few and that the data filter is usable again and again. The data filter is retrievable at any time using the identification.

Advantageous improvements of the method indicated in the independent claim of filtering data between a display and at least one data source are possible by virtue of the measures and developments described in the dependent claims.

It is particularly advantageous that the data filter is deletable by means of a preset message. The memory requirements and memory management for the data filters is therefore reduced as soon as the respective data filter is no longer required.

It is moreover advantageous that an already existing data filter is extendable by further criteria so as to produce a so-called filter chain in order with various

attributes to reduce a list to the requested elements. By means of each new attribute used to restrict or sort list elements a new filter is generated, wherein the data filter constitutes the chaining of the filters.

It is moreover advantageous that the data filter may also be used to sort a list, wherein only the locations of the elements of the list then change but elements are not filtered out of the list.

It is moreover advantageous that in the messages, when they are transmitted with a fixed length, the unused bits are filled up with zeros. Alternatively, it is advantageous that the message operates with a variable length so that only the necessary bits are used. This leads to a saving in transmission bandwidth.

It is moreover advantageous that a changed list, to which e.g. new elements have been added by broadcast reception, is automatically transmitted via the bus so that the function of autonotification is realized. Thus, the display is always kept up to date in terns of the data.

It is moreover advantageous that the messages transmitted by the display are acknowledged by the at least one data source so that the display is informed that its messages have been processed.

The data source according to the invention may be a broadcast receiver and/or a navigation device and/or a storage device. In an advantageous manner a plurality of data sources are connectable to the bus. The bus communication then controls to which data source the respective message is to be transmitted.

In a development, it may be provided that the display takes the form of a control panel, i.e. a head unit.

The invention is described further hereinafter, by way of example, with reference to the accompanying drawings which: Figure 1 shows a bus system; Figure 2 illustrates the method according to the invention in the form of a flowchart; Figure 3 a sequence diagram of a method according to the invention; Figure 4 is a block diagram of a data source according to the invention; and Figure 5 is a block diagram of a display according to the invention.

In motor vehicles, increasing use is being made of bus systems and hence also of bus systems for multi-media systems, wherein the interface commands via said bus are to be limited. In the interaction between a display, which in the present case is referred to hereinafter as a head unit because it also comprises control elements, and a broadcast receiver for digital broadcast signals, the transmission of lists via the bus is a frequently occurring event. According to one aspect of this invention, a method of filtering said data is proposed, wherein by means of a first message the data filter may be generated, by means of a second message the data filter may be extended, even repeatedly, into a filter chain, and by means of a third message the data filter may be deleted. Thus, management and use of the data filters is enabled by means of said three messages.

Said messages are transmitted from the head unit to a data source e.g. of a broadcast receiver. The messages may in said case be of variable length or of a fixed length, wherein in the case of fixed length the unused bits are then filled up by zeros.

Besides a broadcast receiver, it is also possible for further data sources to be connected to the bus. These include navigation devices, mobile radiotelephone stations or storage devices such as e.g. a CD-ROM. The data sources acknowledge the received messages so that the head unit is informed that the messages are being processed by the data source. By means of an identification of the filter a selective calling, a selective extension and the selective deletion of said data filter is possible.

It is therefore also possible for a plurality of data filters to exist alongside one another. DAB (Digital Audio Broadcasting) is a digital broadcasting method which is used, in particular, for the mobile reception of broadcast signals. It further enables the reception of multi- media data which are additionally transmitted along with the audio programs. Many of said data are list elements, such as e.g. a program list or a transmitter list. DRM (Digital Radio Mondial) and DVB (Digital Video Broadcasting) are also capable of additionally transmitting multi- media data along with their own audio programs. Said broadcasting methods also include digital broadcasting methods which are satellite-assisted.

The term, head unit, in the following refers to the display and to the control panel, which a user uses in a vehicle to operate his car radio. Said head unit may additionally be used to operate drives (storage device) for CD-ROMs and/or DVDs

andlor for navigation devices, so that for the multi-media system the head unit offers a universal interface between man and machine in the motor vehicle.

In Figure 1 a bus system is illustrated, wherein the head unit 1 is connected by a bus 2 to a data source 3, here a broadcast receiver for DAB signals. Besides the broadcast receiver 3 it is possible for further data sources such as navigation devices or storage devices or mobile radiotelephone devices to be additionally connectable to the bus 2 and operable via the head unit 1. The bus 2 may be any desired bus system, here it is a MOST bus, i.e. an optical bus. The devices connected to the bus 2 have bus controllers, which enable communication via the bus 2. In the case of an optical bus, electro-optical transducers are to be additionally provided for converting the electrical signals of the components connected to the bus into optical signals for the bus and vice versa. Alternatively, it is possible to use a CAN, USB, PCI or firewire bus.

The head unit 1 controls the broadcast receiver 3 by means of messages, which are transmitted via the bus 2 and are generally also known as API (application program interface) commands, wherein for the transmission of lists data filters are used, which the head unit 1 generates, extends and deletes by means of messages.

With the message CreateFilter() it is possible to generate a data filter.

Parameters, by which the data filter type is to be defined, are declarable in the empty brackets after the message name. For example, the program type (PTY), i.e. message broadcasts (Traffic Announcements), language and audio program. The number of filter types, i.e. the filter parameters, is determined only by the length of the second

parameter. One byte gives 255 filter types, while two bytes allow up to 65535 filter types. There then follows a parameter, which indicates the length specification of the

filter parameters in bytes, followed by the actual filter parameters. The filter parameters are matched specifically to the data filter. Thus, for example, a message broadcast data filter has various message broadcast types, which it may set. The message broadcast filter may appear as follows: filter type: message broadcast filter filter parameter number: 2 parameter 1: 0001 1001 (binary notation) parameter 2: 0000 0000 (binary notation).

In parameter 1, the last 1 defines the so-called alarm announcement, while the penultimate zero defines the traffic announcement. In said manner the sixteen message broadcast types are definable by means of the parameters 1 and 2.

The program type filter is defined as follows: filter type: PTY filter codes - filter parameter number: 1 parameter 1: 16.

Parameter 1 16 here defines e.g. the program type POP.

As an acknowledgement of the message CreateFilter(), the message CreateFilter(filter ID) is transmitted back from the data source. The filter ID (filter identification) specifies a number, by means of which said newly generated filter is selectable and/or retrievable.

With the message AddFilter() a filter may be extended in that with it a first and a second filter are combined by adding additional attributes, i. e. the filter parameters. Thus, it is then possible to build up a chained filter list, i.e. a filter chain.

In said case, always the same filter ID is returned in the acknowledgement for the message AddFilterO as in all other acknowledgements for said data filter.

As a result of the chaining a new functionality is assigned to the entire data filter. The message accordingly appears as follows: AddFilter(filter ID, filter type, filter parameter number, parameter 1, parameter 2,...).

The filter type specifies for which concept filtering is being effected, e.g. the program trove. The filter parameter number specifies how many filter parameters are contained in the message. The parameters (filter parameters) specify by which attributes the data are sorted and/or filtered.

The message DeleteFilterO deletes the entire data filter, i.e. the filter ID is deleted and so the data filter associated with the filter ID is no longer retrievable.

Thereafter, said filter ID is no longer available until said filter ID is assigned to a new data filter. Individual filters from the entire data filter are in said case no longer deletable. The message is defined as follows: DeleteFilter(filter ID).

With DAB the following exemplary applications arise. Program lists of the audio programs in alphabetical order may be retrieved or a program list of all audio programs with Traffic Announcement (traffic reports) or a program list of all programs with News Announcement (news reports) and the program type Pop. Said applications may be combined and extended in any desired manner. The program

types (PTY) include Pop, Rock, Serious Classic, News etc., wherein here 32 program types are defined in international tables and further program types are freely definable. In the case of the announcements, for example, Traffic Announcements, i.e. traffic reports, News, i.e. news reports, or Weather, i.e. weather reports, are distinguishable. For DAB, 16 message broadcast types are defined.

In Figure 2 a method according to the invention is illustrated in the form of a flowchart. In method step 4 the head unit 1 transmits the command CreateFilter in order to generate a data filter in the DAB box 3. The data filter is generated here in dependence upon a user input, e.g. here the user wishes to scan only the available programs with serious classical music. This may however be effected automatically when the head unit 1 requires a specific list of programs or data.

In method step 5 the DAB box 3 acknowledges by means of the message CreateFilter(filter ID) via the bus 2 that the filter has been generated. In said case, the DAB box 3 transfers as a parameter for the acknowledgement message the identification number, the filter ID, for said data filter. In method step 6 the head unit 1 via the bus 2 sends the DAB box 3 a message AddFilter that the already existing data filter with the corresponding identification number is being extended by a further criterion, that in other words a filter chain is to be built up because said further criterion as such is already itself a filter. In method step 7 the DAB box 3 acknowledges said received message AddFilter anew by transmitting the identification number for the data filter with a message AddFilter to the head unit 1.

In method step 8 it is checked whether the data filter is to be extended by further filters by the head unit 1. If so, then there is a return to method step 6 and, if not, then the program continues with method step 9. In method step 9, by means of a command via the bus 2 from the head unit l the filtered list is retrieved from the DAB box 3.

In method step 10, said list is transferred in order in method step l 1 to check whether the filter is still in use. If so, then there is a return to method step 8. If not, then in method step 12 the head unit 1 transmits the message DeleteFilter with the appropriate identification number to the DAB box 3 so that said filter is deleted by the DAB box 3. This is then acknowledged in method step 13 by the DAB box 3 with the same message DeleteFilter, wherein the acknowledgement message with the appropriate identification number is transmitted to the head unit 1.

In Figure 3 a sequence diagram of a method according to the invention is illustrated. Here, messages are exchanged between the head unit 1 and the DAB box 3. Firstly, the message CreateFilter with the filter type Announcement, the filter parameter number 2 and the two parameters, which here are indicated in hexadecimal notation, is established. The parameters signify a search for traffic information and emergency broadcasts in the list, i.e. programs which offer said service. The filter parameter number therefore indicates the number of parameters.

The DAB box 3 acknowledges said message with the message CreateFilter with the identification 2 allocated by the DAB box. Then the head unit l transmits the message AddFilter with the identification number 2, the filter type program type,

the filter parameter number 1 and the single parameter Pop. There are therefore selected from the list all of the programs, which have the program type Pop and the announcements. The DAB box 3 again acknowledges with the message AddFilter (2) that the message AddFilter has been accepted for the filter having the identification 2.

With a further message AddFilter the filter is then extended further by the head unit 1 so that a filter chain of three different filters arises. Said message AddFilter has the identification for the filter, the program type as a criterion which is browsed, the filter parameter number 1 and the attribute News as the parameter.

Thus, the program types Pop and News as well as the announcements are now chained. Again the DAB box 3 acknowledges said extension with the message AddFilter(2). With the next message GetServiceList(2) the head unit 1 then fetches said list, which has been filtered through the filter 2. With the message GetServiceList, the identification number 2 and the filtered elements ofthe list, the list is then transmitted from the DAB box 3 to the head unit 1.

With the message DeleteFilter(2) the data filter with the identification 2 is deleted, wherein the DAB box 3 acknowledges this with the message DeleteFilter(2).

A data filter may also after one use be extended only by further attributes into a filter chain. The head unit 1 and the DAB box 3 comprise means of respectively generating and processing the messages. Such means include processors. The head

unit 1 and the DAB box 3 moreover have memories for filing data, i.e. the data filter and list elements.

The messages are transmitted here with a fixed byte length, wherein unused bytes are filled up with zeros. The receiver recognizes from the zeros that said bytes are not set. Alternatively, it is possible to send messages with a variable length so that only the necessary bytes are transmitted.

In Figure 4 a data source according to the invention is illustrated in the form of a block diagram. A memory 14 is connected to a first data input/output of a processor 15. A second data input/output of the processor 15 is connected to a bus controller 16 as the means of transmitting data. The bus controller 16 is connected to the bus 2. A data input of the processor 15 is connected to a digital part 17. An input of the digital part 17 is connected to a high frequency receiver 18, wherein an input of the high frequency receiver 18 is connected to an aerial 19 for receiving broadcast signals.

The broadcast signals received by the aerial 19 are filtered, amplified and converted into an intermediate frequency by the high frequency receiver 18. The digital part 17 digitizes and effects channel decoding of the received signals. The data stream thus obtained is processed by the processor 15, wherein in particular program lists are filed in the memory 14. Said program lists are then transmitted by the bus controller 16 via the bus 2. Via the bus 2, moreover, the messages from the display 1 are received. The processor 15 is used in said case to evaluate the messages and the data filter generated by the processor 15 is filed in the memory 14.

In Figure 5 a display 1 according to the invention is illustrated in the form of a block diagram. A display panel 20 is connected to a data input of a processor 21.

Connected to a data input of the processor 21 is an input apparatus 22, here a keypad.

A bus controller 23 is connected by a first data input/output to the processor 21 and by a second data inputloutput to the bus 2.

Via the bus controller 23 the display 1 receives from the bus 2 data, which are to be displayed on the display panel 20. Here, the transmitter identifier SWR is displayed. The display panel 20 here is a TFT screen of the head unit 1. User inputs relating to program tuning are effected by means of the input apparatus 22. In dependence upon said user inputs the processor 21 transmits the messages to generate, extend or delete a data filter for the data, which are retrieved from the data source. The messages and the format of said messages is filed in a memory associated with the processor 21. The display panel 20 comprises an activating device for displaying the data coming from the processor 21.

In a development, it may be provided that the display I comprises a plurality of display panels 20 and/or a plurality of input apparatuses 22 and/or a plurality of processors 21 and/or bus controllers 23. Thus, for example, operator control may be effected at a plurality of seats in a vehicle simultaneously. If there is one processor 21 for a plurality of input apparatuses, then the processor 21 may have a multi-

tasking operating system in order to operate the input apparatuses.

Claims

1. A method of filtering data transmitted between a display and at least one data source, wherein the display requests data from a list of the at least one data source, the requested data are filtered by a data filter, the display transmits a first message to the at least one data source, and wherein the at least one data source through evaluation of the first message generates the data filter, and the at least one data source assigns an identification to the data filter and communicates the identification to the display.

2. Method according to claim 1, wherein in the first message a data filter type, a number of filter parameters and the filter parameters are indicated, the filter parameters being used to filter the data.

3. Method according to claim 1 or 2, wherein the data filter is deleted by a second message, which is transmitted from the display to the at least one data source.

4. Method according to claim 3, wherein in the third message the identification of the data filter is indicated.

5. Method according to claim 1 or 2, wherein the data filter is extended into a filter chain by at least one third message, which is transmitted from the display to the at least one data source.

6. Method according to claim 5, wherein in the third message the identification of the data filter, the data filter type, the number of filter parameters and the filter parameters, by which the data filter is extended, are indicated.

7. Method according to any of the preceding claims, wherein the data are sorted by the data filter.

8. Method according to any ofthe preceding claims, wherein the first, second and third message are transmitted with a fixed byte length, wherein the bytes unused by a message are filled up in the message by zeros.

9. Method according to any of claims 1 to 7, wherein the messages are used with a variable byte length.

10. Method according to any of the preceding claims, wherein the at least one data source acknowledges the messages from the display.

11. Method according to any ofthe preceding claims, wherein upon a change of the filtered data in the at least one data source the filtered data are transmitted unrequested from the at least one data source to the display.

12. Method according to any ofthe preceding claims, wherein the first and/or the second and/or the third message is generated by a user input.

13. Method according to any of the preceding claims, wherein the display and the at least one data source are connected by a bus.

14. A data source, comprising a memory for data, a first processor for processing the data, and means of transmitting the data to a display, the first processor comprising means of generating, extending and deleting a data filter for the data and the data source comprising means for receiving messages from the display, the messages indicating whether the data filter is to be generated or extended or deleted.

15. Data source according to claim 14, wherein the data source takes the form of a broadcast receiver and/or a navigation device and/or a storage device.

16. Data source according to claim 14 or 15, wherein the data source is connectable to a bus.

17. A display comprising a display panel for displaying data, a second processor for processing the data and means for receiving the data, wherein the display comprises means for generating and transmitting messages, the messages indicating whether a data filter in a data source is generated, extended or deleted.

18. Display according to claim 17, wherein the display comprises an input apparatus.

19. Display according to claim 1 7 or 18, wherein the display comprises a plurality of display panels and/or a plurality of input apparatuses and/or a plurality of processors andlor a plurality of means of receiving the data and/or means of generating and transmitting the messages.

20. Display according to claim 17, 18 or 19, wherein the display is connectable to a bus.

21. A method of filtering data substantially as hereinbefore described with reference to the accompanying drawings.

22. A data source substantially as hereinbefore described with reference to the accompanying drawings.

23. A display substantially as hereinbefore described with reference to the . accompanying drawings.