AU2005202619B2 - System for the automatic updating of the nit table during transmodulation at headend - Google Patents

Description

P/00/011 Regulation 3.2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ORIGINAL TO BE COMPLETED BY APPLICANT Name of Applicant: ANGEL IGLESIAS, S.A. Actual Inventor: Marco Dominguez Bonini Address for Service: CALLINAN LAWRIE, 711 High Street, Kew, Victoria 3101, Australia Invention Title: SYSTEM FOR THE AUTOMATIC UPDATING OF THE NIT TABLE DURING TRANSMODULATION AT HEADEND The following statement is a full description of this invention, including the best method of performing it known to us:- -2 SYSTEM FOR THE AUTOMATIC UPDATING OF THE NIT TABLE DURING TRANSMODULATION AT HEADEND DESCRIPTION When DVB-S/C/T (Digital Video Broadcasting-Satellite/Cable/Terrestrial) digital 5 (satellite, terrestrial or cable) television signals have to be taken to an installation that uses a different distribution means, for example they are received from satellite (DVB-C), a transmodulation must be carried out (see for example FR 2825221). The transmodulation can be carried out in two ways: transparently or by updating the NIT (Network Information Table) tables. 10 If it is carried out transparently, the digital signal transport raster is not touched and only the channel encoding is affected in order to adapt it to the new means, for example coaxial cable. Transparent transmodulation renders the NIT tables useless, as they are specific for the means used; this could be a problem for the receivers and that is why at times the NIT 15 tables must be modified in the transmodulation, adapting them to the transmission means (for example, cable) for the receivers. This requires the manual construction of an appropriate NIT table and its remote updating every time there is a change in the configuration of the distribution network, which is expensive and subject to errors. 20 This invention proposes an automated system to carry out this function. In the system targeted by the invention, the process is as follows: 1.- A piece of equipment connected to the headend, or part of it, acts as master. This equipment can be a dedicated headend controller or if not, and preferably, it can be one of the transmodulators that assumes the function of master after a directionning 25 process. 2.- One of the transmodulators with NIT processing capacity extracts the PSI/SI information required to generate the output NIT table and transmits it to the master. PSI/SI are general information tables. 3.- The master interrogates each one of the modules and obtains the parameters of 30 the digital input and output signals. 4.- Based on this information the master generates an output NIT table with the information required for the receivers connected to the output network to be able to be correctly tuned to all the headend transmodulated signals. All the information present in -3 the original NIT, which is relevant in the output network, is reentered into the NIT table generated. 5.- The master module sends this new NIT to all the transmodulators equipped with NIT table modification capacity (it is not essential to modify the NIT in all the channels; it 5 may be sufficient to modify just one of them). 6.- Each one of the transmodulators equipped with NIT modification capacity activate this function on having the modified NIT table. 7.- The master carries out an automatic monitoring of the original NIT and of the headend configuration to keep the NIT table transmitted to the output up to date. 10 With the system targeted by the invention the function is automated, without errors and in a less costly manner. In order to understand the subject of this invention better, a preferential form of practical execution is illustrated on the drawings, subject to incidental changes that take nothing away from its foundation. 15 Figure 1 is a representation in block diagram of a practical execution of the system targeted by the invention. Below an example of a non-limitative practical execution of this invention is described. A television operator (9) by means of satellites (16) sends its programmes to space 20 through channels: channel Sat,, channel Sat 2 , ..... channel Sat, whose original NIT contains, among other parameters, frequencies 11535, 11600 ... 11900 MHz, knowing that the users' receivers (12) must operate to capture these channels at a frequency of, for example 300, 308 ... 332 MHz, together with other typical parameters of the transmission means and encoding used. 25 It is a question of modifying the original NIT and automatically transforming it into a modified NIT that adapts to the output network (13) (normally coaxial cable). A transmodulator (81), (82),.... (8n) for example MDI-900 is comprised of: a) a receiver (2) of the input signal (DVB), for example satellite (Sati), (Sat 2 ) .... (Sat,), that is, (DVB-S), but this may be cable (C) or terrestrial (T), which digitally sends 30 the transport raster to b) a NIT table processor (3), which is where the NIT table is modified; c) the modified transport raster is sent to a DVB-C cable modulator (4) and sends the DVB-C cable signal to -4 d) an agile frequency converter (5), whose output signal is a DVB-C cable signal in radiofrequency (RF), for example 300 MHz. Commonly, a NIT table refers to a group of satellite transponders, which transmit one or several (Sat) digital signals each one. 5 In the system of the invention there is a transmodulation headend (7), which may have one or several modules (81), (82), ... (8n) for example, a module for each transponder associated with the television operator (9) by satellite (if there is a DVB-S network at the input). Each module (81), (82), ... (8,) is comprised of a transmodulator (1) and a 10 microprocessor (10) connected to its NIT table processor (3) and with the microprocessors (10) connected by means of a communications bus (11). The system proceeds in the following preferential way: a) one of the transmodulators (8n,) is chosen, which assumes the function of master after a directionning process; 15 b) one of the transmodulators (8) with NIT table processor (3) extracts the information from PSI/SI general information tables that is required to generate the output NIT table and transmits it to the master (8,); c) the master (8,) interrogates each one of the modules (81), (82) .... and obtains the parameters of the digital input (Sati), (Sat2) ... (Sat,) and output (61), (62) .... (6n) signals; 20 d) based on this information, the master (8,) generates an output NIT table with the information necessary for the receivers (12) connected to the output network (13) to be able to correctly tune to all the signals transmodulated by the headend (7) re-entering all the information present in the original NIT that is relevant in the output network (13) into the NIT table generated; 25 e) the master module (8,) sends this new NIT (14) to all the transmodulators (1) equipped with NIT table processor (3) for them to have the modified NIT table; f) the master (8n) carries out an automatic monitoring of the original NIT and of the configuration of the headend (7) to keep the NIT table transmitted to the output up to date. Where the terms "comprise", "comprises", "comprised" or "comprising" are used 30 in this specification, they are to be interpreted as specifying the presence of the stated features, integers, steps or components referred to, but not to preclude the presence or addition of one or more other feature, integer, step, component or group thereof.

Claims (2)

1. A system to automatically update the NIT table during the transmodulation in headend, where each transmodulator has a DVB digital signal DVB-S/C/T receiver block, a NIT table processor, a digital DVB-S/C/T modulator, a frequency converter, 5 whose output signal is a DVB digital signal in radiofrequency, wherein a transmodulation headend, made up of one or several modules in agreement with the transponders associated with a television operator, each module including a transmodulator and a microprocessor connected to its NIT table processor and with the microprocessor(s) connected by means of a communications bus and carrying out the following: 10 a) one of the transmodulators is chosen, which assumes the function of master after a directioning process; b) one of the transmodulators with NIT table processor extracts the information from the PSI/SI general information tables that is necessary to generate the output NIT table and transmits it to the master; 15 c) the master interrogates each one of the modules and obtains the parameters of the digital input and output signals; d) based on this information, the master module generates an output NIT table with the information required for the receivers connected to the output network to be able to tune correctly to all the signals transmodulated by the headend re-entering all the 20 information present in the original NIT that is relevant in the output network into the NIT table generated; e) the master module sends this new NIT to all the transmodulators equipped with NIT table processor for them to have the modified NIT table; f) the master module carries out an automatic monitoring of the original NIT 25 and of the configuration of the headend to keep the NIT table transmitted to the output up to date.

2. A system, substantially as hereinbefore described with reference to the accompanying drawing. 30 Dated this 16 th day of June, 2005 ANGEL IGLESIAS, S.A. By Their Patent Attorneys CALLINAN LAWRIE 64Di A 7n/