MXPA99010194A - Method for determining a predetermined frequency associated with a transport stream in a digital broadcast receiver - Google Patents

Abstract

A method for determining a predetermined frequency associated with a transport stream in a digital broadcast receiver, comprises scanning (20, 21;26, 27, 28;30, 31) a frequency range, finding (22) a first frequency (FST) at which a first transport stream is received, reading (23) first identifying data (ID) from the first transport stream, which allows to uniquely identify the first transport stream, extracting (24) a first predetermined frequency (F') associated with the first identifying data from a database (25) by using the first identifying data, the database associating a predetermined frequency with predetermined identification data. The method may be used in networks where the actual broadcasting frequency of the transport stream is different from the predetermined frequency of this transport stream, as contained in a network information table.

Description

METHOD TO ASSOCIATE IN A DIGITAL DIFFUSION RECEIVER UNA TRANSPORT CURRENT WITH A PREDETERMINED FREQUENCY DESCRIPTION OF THE INVENTION The invention relates to digital broadcast receivers. More precisely, the invention relates to a method for determining a predetermined frequency associated with a transport stream. The invention also relates to a method for selecting a service from among a plurality of available services of at least one first transport stream. The invention also relates to a method for finding a new frequency of a new transport stream. A digital broadcast receiver is a device which allows to use digital data broadcast on, for example, a cable network, a satellite or a terrestrial transmitter. The digital diffuser receiver may be known under the name of "top-mounted box" or "integrated receiver decoder". The digital data is typically broadcast on one of a plurality of transport streams (TS), each TS is broadcast at a different frequency. The digital diffuser receiver can be designed to receive any of a plurality of TSs by tuning to the frequency corresponding to the desired TS.

The transport stream typically comprises a plurality of services, i.e., audio, and / or video programs, interactive application software ... and attached service information. The service information may describe, for example, a predetermined frequency to which the TS is broadcast. It can also describe in which of other predetermined frequencies other TSs are broadcast especially if the digital broadcast receiver is also designed to receive these other predetermined frequencies. The service information can also describe what services are available in the TS but also what other services are available in other TSs at the other predetermined frequencies. Therefore, it is possible to use service information to compile for the TS or for a plurality of TSs taken from other TSs, a list of available services and associated to each service with the predetermined frequency of the TS in which the service is available. when a digital broadcast receiver service is selected that is tuned to the appropriate associated predetermined frequency. The service information may further comprise a version indicating a duration of at least a portion of the information of the broadcast service. In this way, the digital broadcast recipient can update an existing list of available services if the information of the disseminated version is more current than the information of the version of the services in the existing list. A new version information may also indicate that a TS is no longer broadcast or that a new TS is broadcast at a new predetermined frequency. The digital broadcast receiver can update the list of available services accordingly. A problem arises when the service information is not completely consistent with the reality of the services available in a plurality of TSs, for example, if a TS does not broadcast on the associated predetermined frequency indicated in the service information but at a different frequency of the predetermined frequency. In this case, each TS can be disseminated and identified using the service information. However, it is not possible to keep an updated list of available services regarding the plurality of the TS or to tune the new frequency of a new TS using the service information in a manner described in previous paragraphs because the predetermined frequencies do not have a predetermined relationship with respect to the frequency at which the TSs are broadcast. A solution to update the list of available services therefore the existing and / or new TS is to explore the frequency and monitor by the TS. Every time a TS is found, the list of available services is updated, services which are in that TS and a current frequency of that TS is directly or indirectly associated with the services found. This way of updating may require the development of a different system than that used in the information service to update the list of available services and requires a relatively long time to explore the frequency for each update. The fact that a current frequency needs to be used instead of the broadcast frequency for location and tuning to a service and its TS also requires a different system to which the information of the broadcast service is based. In a first aspect, the invention suggests solving the problem described above using a method for determining a predetermined frequency associated with a transport current in a digital broadcast receiver, which comprises: exploring a range of frequencies, finding a first frequency at the which receives a first transport stream, read the first identification data from the first transport stream, which allows to uniquely identify the first transport stream, and • extract a first predetermined frequency associated with the first data of identification from the database by using the first identification data, the database associates a predetermined frequency with predetermined identification data.

A first preferred embodiment of the invention comprises: retrieving a description table of the service containing a list of available services, of the first transport stream, establishing a current list of services, storing the current list of services. A second preferred embodiment of the invention comprises: retrieving a table of network information which comprises at least the database, from the first transport stream, storing the network information table. A third preferred embodiment of the invention comprises: storing the first frequency for the transport stream. A fourth preferred embodiment of the invention comprises: calculating a first frequency shift by providing the first predetermined frequency of the first frequency storing the first frequency current for the first transport stream.

In a second aspect, the invention suggests solving the problem described above using a method for selecting a service with a digital broadcast receiver, the service is one of a plurality of services available from at least one first transport stream received to a first frequency, which includes: selecting the service, identifying the first transport stream in which the service is available, • extracting a first predetermined frequency associated with the first transport stream from a database, the associated database a predetermined frequency with a predetermined transport current, calculating the first frequency from the first predetermined frequency, tuning the digital broadcast receiver to the first frequency to receive the first transport current, and reading the service from the first current Of transport. A fifth preferred embodiment of the invention comprises: searching a conversion table for the first predetermined frequency, the conversion table comprising, for a predetermined frequency, an associated frequency, and extracting the first frequency from the conversion table. A sixth preferred embodiment of the invention comprises: • searching for a frequency shift table for the first predetermined frequency, the frequency shift table comprises for a given frequency, an associated frequency shift, and extracting from the frequency shift table a first frequency shift which is a difference value of the first predetermined frequency and the first frequency. In a third aspect, the invention suggests solving the problem described above using a method to find a new frequency of a new transport stream using a digital broadcast receiver, comprising: receiving a first transport stream at the first frequency, recording a update event, • extract new information from the first transport stream, new information associates predetermined frequencies with predetermined transport streams, compare the new information with a database that associates predetermined frequencies with predetermined transport streams, determine in the information new a new default frequency associated with the new transport streams which is different from the predetermined frequencies in the database, and • initiate an update tuning to find the new frequency at which the transport stream can be received new. A seventh embodiment of the invention comprises: scanning a frequency range, finding a frequency used in which a transport current is received, reading identification data of the transport current, which allows to uniquely identify the current of transport, • set a value of the new frequency to a value of the frequency if the identification data identifies the transport stream as a new transport stream. An eighth embodiment of the invention comprises: • updating the database using the new information. The invention will now be described using examples and making references to Figures 1 to 14, which: Figure 1 contains a schematic block diagram of a connected digital broadcast receiver, Figure 2 shows an initiation flow diagram of a digital broadcast receiver, Figure 3 shows an update flow diagram of the digital broadcast receiver. service line, - figure 4 shows another digital diffusion receiver initialization flow diagram, figure 5 contains a network topology construction diagram, figure 6 shows a flow chart for determining a predetermined frequency associated with a TS, Fig. 7 shows a scan flow diagram, Fig. 8 shows a flow chart of monitoring, Fig. 9 shows a flow diagram for determining a predetermined frequency associated with a TS, Fig. 10 contains a diagram of network topology construction, figure 11 shows a tuning flow diagram, figure 12 contains an illustration of a network mechanism and tuning, Figure 13 shows a flowchart for updating a new frequency of a new TS, Figure 14 shows a flow chart for determining a new frequency value of a new TS. With reference to Figure 1, a digital broadcast receiver 1 receives data from a provider 2, which comprises at least one service, the digital broadcast receiver 1 compiles a global list of services 3 available from the provider 2. The global list of services 3 can be displayed, for example, on the screen of a TV 4 using a user interface (not shown), or on any data display device such as a remote control screen or a dedicated screen (not shown) connected to digital broadcast receiver 1. A user 5 can select a service from the global service list 3 using for example the user interface by means of a pointer on the screen. In this way the user 5 instructs the digital broadcast receiver 1 to properly tune in and execute the selected service, and to transmit any audio and / or visual information to the TV 4 or to any other appropriate connected device, for example a wireless device. audio hi-fi (hi-fi) or a homemade electrical device. The provider 2 can provide data in a transport stream (TS), a TS is broadcast at a predetermined frequency. In addition to one or a plurality of services, the TS can provide service information (SI), which, for example indicates a unique identification of the TS, predetermined frequencies identifications of TS available for the digital broadcast receiver 1 and a description of the services available in one or a plurality of available TSs. Many of the existing digital television standards implement the described features of TS and SI.

An example is the European standard for digital video broadcasting (DVB) which specifies a format and content of such characteristics. Another example is a standard called ATSC. In DVB, a part of the IS is constituted in a network information table (NIT) and a service description table (SDT). The NIT contains a frequency plan of a given network, that is, information about predetermined frequencies to which the digital broadcast receiver must be tuned to receive each TS available from the provider. The SDT includes the services available from a TS that include an identification and an exploration of each service. There can be one SDT for each TS. Each TS can contain the SDT for services available in other TS. With reference to Figure 2, an initialization of a digital broadcast receiver, for example a standard DVB receiver, starts at number 6 and a predetermined frequency BF of a TS is established at number 7. The NIT and therefore less an SDT are read in 8 and are used in 9 to make a list 10 of available services. The NIT and SDT information allows a predetermined frequency to be associated with each of the services available in the list 10. With reference to figure 3, an update event 11 initiates the digital broadcast receiver for updating in 12 of the existing list 10 and obtain an updated list of available services 13. The update event can be, for example, specific information disseminated as part or not of the SI and which indicates a change in a version number of the NIT and / or SDT . The NIT and / or SDT is / are read in update 12 and the version number is set as the most current value. In DVB networks, TSs are broadcast at predetermined frequencies indicated in the NIT. In some networks, it may happen for various reasons that the TSs are broadcast at frequencies which are not indicated in the SI. Therefore, it is not possible to use standard DVB methods as shown with reference to FIGS. 2 and 3 to initialize a digital broadcast receiver in such networks. An example of these latter networks is a satellite master antenna TV network (SMATV). The SI in the SMATV network can be the same as in standard DVB. Referring now to Figure 4, an initialization of a digital broadcast receiver in, for example, a SMATV network starts at number 14. A frequency at which the TS is available is scanned at number 15. This can be done , for example, by scanning a frequency F. If such frequency is at 16, a current SDT is read at 17 at that frequency and an associated frequency Fl equal to the tuned frequency F is established and stored at number 18. In number 19 a list of available services in the network is updated with information from the current SDT read, each service of the current SDT is associated with the associated frequency Fl. Then a new search is started at number 15 to find additional TSs. If TS is not found at the number 16 (N) at the tuned frequency, then the search 15 continues. Referring now to Figure 5, a network topology can be constructed. The frequency is scanned from a frequency of initiating FO to a final frequency FE. For each frequency Fl, F2, ..., FN in which a TS is found, read YES. More precisely, the current SDT is read on each frequency, and identification data (TSIdl, TSId2, ..., TSIdN), a tuned frequency (Fl, F2, ..., FN) and a list of available services (SDT1, SDT2, ..., SDTN) in a table which constitutes the network topology. The network topology can be used for search tuning information for a selected service. With reference to Figure 6, initialization of a digital broadcast receiver begins with the number 19. An exploration 20 of a frequency carried out and a monitoring 21 checks the data possibly received at that frequency. If no data is received or if the received data can not be recognized as a TS Provider, a case consideration 22 takes branch N and exploration 20 followed by monitoring 21 is performed again. If the data is received and the received data is acknowledged as being provided by a TS (branch Y), then a first frequency FST has been found at which a first transport stream is received. A reading 23 of the first identification data ID of the first TS allows a unique identification of the last TS. An extraction 24 uses the first identification data 10 to extract a predetermined frequency F1 from a database 25. The database 25 contains information which directly or indirectly associates the predetermined frequencies with predetermined identification data. The database 25 can be stored for example in a memory of the digital broadcast receiver or it can be retrieved from a network. With reference to Figure 7, a flow diagram illustrates an example for carrying out the scan 20. After a start event 26, the frequency F is set to the number 27, and the frequency F is comprised in a width of frequency band scan. With reference to Figure 8, a flow chart illustrates an example for carrying out monitoring 21. Once the frequency F is tuned, a case check 30 is terminated if a received signal corresponds to the received data. In case of an affirmation (branch Y), the received data is transmitted in 31 to be verified in 22 (see figure 6). If this is not the case, the exit stage 31 is derived. In networks in which the TSs are broadcast at frequencies different from the predetermined frequencies expected for these TS, the method illustrated in FIG. 6 can be used to establish an association between the predetermined frequencies and the current different frequencies. Any known application in a digital broadcast receiver which requires the use of a predetermined frequency F ', for example an application which instructs the digital broadcast receiver to tune to the predetermined frequency F1 to receive a particular service, can find the frequency FST current using the existing association between F 'and FST. With reference to Figure 9, and in a manner similar to that shown for Figure 6, a digital broadcast receiver is initialized at number 19. Scanning 20 and monitoring 21 are carried out. If consideration 22 of the case determines that data is not received or that the data received does not come from a TS, then branch N leads to a scan 20. If the data of a TS are received at number 14 (branch Y), a recovery 32 is carried out from an SDT from the TS, and the SI from the SDT used to establish at 33 a current list of services 34, which it can be stored, for example, in a list memory (not shown) of the digital broadcast receiver. After the mentioned branch Y, after consideration 22 of the case, a recovery 35 of an NIT is carried out from the TS and the NIT is stored in the step 36. The information of the NIT can be stored in a that the database 25 is obtained with associated predetermined frequencies, with predetermined identification data, that is, with the predetermined TS. After recovery 32 of the SDT, a reading 37 of the ID identification data of the retrieved SDTs allows a unique identification of the TS at the tuned frequency F. The extraction 24 uses the identification data ID to extract the predetermined frequency F 'from the database 25. In this way, the frequency at which the TS is broadcast can be associated with a predetermined frequency of the TS contained in the NIT. A topology table can be constructed as shown in figure 10. For each frequency Fl, F2, ..., FN included between the start frequency FO and the final frequency FE, a TS is found and an SI is read. More precisely, the current SDT is read on each tuned frequency (Fl, F2, ..., FN), which includes identification data (TSIdl, TSId2, ..., TSIdN), and the available service lists ( SDT1, SDT2, ..., SDTN), but one or a plurality of current NITs are also read (NIT1, ..., NITN). The identification data (TSIdl, TSId2, ..., TSIdN) are used to extract the associated predetermined frequencies F'l, F'2, ..., F 'from the current NITs (NIT1, ..., NITN). N.

Finally, the frequency displacements? Fl,? F2, ..,? FN are calculated by subtracting the tuned frequencies of the predetermined frequencies respectively: ? Fl = F'l - Fl? F2 = F'2 - F2 ? FN = F'N FN In this way it is always possible to tune a TS when its predetermined frequency is known from the NIT, that is, the frequency of the TS is calculated by subtracting the frequency shift from the predetermined frequency: Fl = F'l -? Fl F2 = F'2 -? F2 FN = F'N? FN Referring now to Figure 11, a start event 38, for example, pressing a selection button by the user, initiates a selection 39 of a service. This is what can happen when a user searches for a list of available services and selects a service using a user interface. An identification 40 of a TS is made in which the selected service is available. The identification 40 may use information contained in the list of available ST services, the information is not necessarily shown to the user. Once the TS has been identified and 41 is extracted, the TS information is used to search a database 42 for an associated predetermined frequency. The database 42 may be based, for example, on the table shown in Figure 10, in which each row contains an identification of a TS and its predetermined frequency. A calculation 43 determines at which frequency of TSF the TS can be received. The calculation 43 uses the predetermined frequency 30 of the database 42. There may be several ways to calculate the frequency TSF. One way can be, for example, by using the table shown in Figure 10, by extracting a frequency shift? TSF and by calculating the frequency TSF by subtracting the frequency shift? TSF from the predetermined frequency. Another way would be looking for a correspondence database using the default frequency. The correspondence database comprises information associating the predetermined frequencies of the TS with the current frequencies to which the TS can be received. In a tuning 44, the digital broadcast receiver is tuned to the TSF frequency at which the TS 45 is received and the selected service can be read. An illustration of a tuning mechanism in Figure 12 shows an example of how the modules can be used to tune to DVB in a network where the TS is received at frequencies different from the predetermined frequencies included in the NIT. A user wants to select an Sp service at 46. At 47, the NIT service information for Sp is retrieved from the specific NITp, the information of * services is stored in a topology table. The service information of NITp after number 48 is sent to the DVB tuning module together with an instruction 49 for selecting and tuning the Sp service. The tuning module DVB instructs at number 50 the tuner of the digital broadcast receiver to tune the predetermined frequency F'p in which the service Sp is available according to NITp, and the tuner extracts, at number 51, information from the topology table in order to find a current frequency Fp to which it is broadcasted in actually the Sp service. Finally, the tuner tunes to the current frequency Fp.

In this way, the tuner modules originally designed for standard DVB networks can be reused in SMATV, and therefore save development costs for a new module specific to SMATV. Referring now to Figure 13, a start 52 causes a tuning 53 of the digital broadcast receiver to the first frequency at which the first TS is received. This is what can happen when a user tunes in to receive a service from the first TS. In a register 54, an update event 55 is notified in the digital broadcast receiver. Event 55 can be broadcast, for example, as if in the first frequency. As a consequence, the new SI is extracted at number 56 of the first TS. The new SI can be, for example, a new NIT or a new SDT. The new SI is compared, at number 57, with the SI stored in a database 58. More precisely, the comparison reveals whether the new SI comprises a new predetermined frequency NPF associated with a new transport stream, not stored previously in the database 58. A finding step 59 initiates a finding of a new frequency NF corresponding to the new predetermined frequency NPF. The new TS will be received on the new frequency NF. With reference to Figure 14, a start 60 starts a way to find the new frequency NF. The scanning of a frequency is carried out while monitoring 21 verifies the possibility of data received at that frequency. If the verification 22 reveals that data is not received or that the data received is not from a TS, scanning 20 continues (branch N). If the verification 22 reveals that the data is received from a TS (branch Y), the reading 23 allows to obtain identification data which allow to uniquely identify the TS. A check 61 checks if the identification data identifies the new TS, in case it is not so (branch N) the scan 20 is started again. If the new TS of NTS is identified, the value of the new frequency is established with respect to the current tuned frequency at which the new TS is received. In this way, the new frequency NF of the new TS has been determined. Optionally, the database 58 of Figure 13 can be updated with the new predetermined frequency NPF and the information that allows associating the new frequency NF with it.

Claims (11)

1. A method for determining a predetermined frequency associated with a transport stream in a digital broadcast receiver, comprising: scanning a range of frequencies, finding a first frequency at which the first transport stream is received, reading the first identification data from the first transport stream, which allows to uniquely identify the first transport stream, extract a first predetermined frequency associated with the first identification data from a database by using the first data of # identification, the database associates a predetermined frequency with predetermined identification data.

2. A method for determining a predetermined frequency, as described in claim 1, characterized in that it comprises: retrieving a service description table containing a list of available services, from the first transport stream, establishing a current list of services, • store the current list of services.

3. A method for determining a predetermined frequency, as described in claim 1, characterized in that it comprises: recovering a table of network information which comprises at least one database, from the first transport stream, storing the table of network information.

4. A method for determining a predetermined frequency, as described in claim 1, characterized in that it comprises: storing the first frequency for the first transport stream.

5. A method for determining a predetermined frequency, as described in claim 1, characterized in that it comprises: calculating a first frequency shift by subtracting the first predetermined frequency of the first frequency, storing the first frequency shift for the first transport current .

6. A method for selecting a service using a digital broadcast receiver, the service is one of a plurality of services available from at least one first transport stream received at a first frequency, comprising: selecting the service, • identifying the first stream of transport in which the service is available, extract a first predetermined frequency associated with the first transport stream from a database, the database associates a predetermined frequency with a predetermined transport stream, calculate the first frequency to From the first determined frequency, tune the digital broadcast receiver for the first frequency, to receive the first transport current, read the service from the first transport stream.

7. A method for selecting a service, as described in claim 6, characterized in that it comprises: searching for a conversion table for the first predetermined frequency, the conversion table comprises for a predetermined frequency an associated frequency, and extracting from the conversion table the first frequency.

8. A method for selecting a service, as described in claim 6, characterized in that it comprises: searching for a frequency shift table for the first predetermined frequency, the frequency shift table comprises for a given frequency an associated frequency shift, and extract from the frequency shift table a first frequency shift which is a value of difference between the first predetermined frequency and the first frequency.

9. A method for finding a new frequency of a transport stream using a digital broadcast receiver, comprising: • receiving a first transport stream at the first frequency, recording an update event, extracting new information from the first transport stream, the new information associates predetermined frequencies with predetermined transport streams, comparing the new information with a database associating predetermined frequencies with predetermined transport streams, determining in the new information a new predetermined frequency associated with the new transport streams which be different from the predetermined frequencies in the database, start an update starting to find the new frequency at which the new transport stream can be received.

10. A method for finding a new frequency of a new transport stream, as described in claim 9, characterized in that it comprises: • scanning a range of frequencies, finding a used frequency at which the transport current is received, reading data from identification of the transport current, which allow to uniquely identify the transport current, establish a value of the new frequency to a value of the frequency if the identification data identify the transport current as a new transport current.

11. A method for finding a new frequency of a new transport stream, according to any of claims 9 or 10, characterized in that it comprises: updating the database using the new information.