WO2005060261A2

WO2005060261A2 - System comprising several set-top boxes sharing one modem, set-top boxes and method for managing access

Info

Publication number: WO2005060261A2
Application number: PCT/EP2004/053520
Authority: WO
Inventors: Philippe Leyendecker; Mike Arthur Derrenberger; Raoul Monnier
Original assignee: Thomson Licensing SAS
Current assignee: Thomson Licensing SAS
Priority date: 2003-12-15
Filing date: 2004-12-15
Publication date: 2005-06-30
Anticipated expiration: 2006-06-15
Also published as: WO2005060261A3

Abstract

The invention relates to a system for receiving broadcast digital data from an operator, the system comprising a main terminal (1) containing a modem (14, 141, 143) and at least one secondary terminal (2) linked to the main terminal via a communication link (40). Each secondary terminal linked to the main terminal is able to use the modem of the main terminal to communicate information about its localization to the operator.

Description

System comprising at least two terminals for receiving broadcast digital data in different rooms of a house, terminals and method for managing access to a modem to be used in such a system Field of the invention The present invention relates generally to the reception of digital data, such as video signals, on several terminals in a house and more particularly to a system comprising a main terminal and at least a secondary terminal for receiving broadcast digital data in different rooms of a house.

Background art Up to recently, people used to receive digital Tv" signals on a single terminal, called a set-top box, linked to a TV set, in their house but now, many users want to receive digital data (which can contain video signals but also other kinds of data) in several places of their house. Some Pay-TV operators wish to offer their subscribers the possibility to install several set-top boxes in their home in order to enjoy their services on several TV sets without imposing them a full rate subscription for each additional set-top box, but rather a subscription at a lower rate. However in this case, the operator wants to control that the additional set-top boxes with a reduced subscription rate are actually used in the same home as the main set-top box (for which a full rate is paid). A known solution to ensure that all set-top boxes are in the same dwelling consists in the triggering of regular callbacks from the set-top boxes to a Subscriber Management System of the operator during which the set-top box communicates information on its location. In order to do this, the set-top boxes must be equipped with a modem. Typically, the modem is a PSTN (Public Switched Telephone Network) modem and the set-top box must be connected to a phone plug to transmit its caller identifier to the Subscriber Management System. The modem may also be a satellite modem with an associated localization system or a modem where the exact geographic coordinates need to be entered during the installation phase. A problem with this solution is that all set-top boxes need to be equipped with modem which renders the solution quite costly. In addition, phone lines are not necessarily available in all rooms of a house and when a PSTN modem is used in the set-top box, the set-top box can only be installed close to a phone plug. Summary of the invention The present invention solves this problem by providing a system for receiving broadcast digital data from an operator, said system comprising a main terminal containing a modem and at least one secondary terminal linked to the main terminal via a communication link, characterized in that the at least one secondary terminal is able to use the modem of the main terminal to communicate information about its localization to the operator. In a multi set-top boxes configuration according to the invention, at least one set-top box called the main set-top box, is equipped with a modem and the other set-top boxes which are able to communicate with the main set-top box through a physical link, use the modem of the main set-top box to communicate information about their localization to the Subscriber Management System which can then verify the co-location of all set-top boxes of the household. The system of the invention can furthermore exhibit one of the following characteristics: - the communication link between the main terminal and the at least one secondary terminal is adapted to use a link for supplying the broadcast digital data to the terminals; - the main terminal comprises means for managing the share of the modem between the terminals; - the modem is a Public Switched Telephone Network modem intended to be connected to a phone line of a house in which the terminals are located; - the modem is a satellite modem intended to be connected to a satellite antenna having bi-directional communication means, said satellite modem being able to communicate its geographic coordinates to the operator. The invention also relates to a digital terminal for receiving broadcast digital data from an operator, the digital terminal containing a modem, characterized in that the digital terminal is able to be linked to at least one secondary terminal via a communication link and in that the digital terminal comprises means for managing the share of the modem between the terminals in order that the terminals be able to communicate information about their localization to the operator. The invention further relates to a digital terminal for receiving broadcast digital data from an operator, the digital terminal being adapted to be linked to one main terminal containing a modem, characterized in that the digital terminal is adpated to use the modem of the main terminal to communicate information about its localization to the operator. Finally, the invention relates to a method for managing access to a modem, the modem being contained in a main terminal and being adapted to be used by the main terminal or by at least one secondary terminal linked to the main terminal, characterized in that the method comprises the steps, at the main terminal, of: checking whether the main terminal needs to use the modem; and in case the main terminal needs the modem, allocating the modem to the main terminal; in case the main terminal does not need the modem, checking whether any secondary terminal linked to the main terminal needs to use the modem; and in case one secondary terminal needs the modem, allocating the modem to this secondary terminal.

Brief description of the drawings The various features of the present invention and its preferred embodiments will now be described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 illustrates an overall architecture of a system according to the invention. Fig. 2 illustrates a first embodiment of the invention. Fig. 3 illustrates a second embodiment of the invention. Fig. 4 and 5 are flowcharts showing the steps carried out in a main and in a secondary set-top box according to the invention. Fig. 6 is a flowchart illustrating a mechanism for an automatic set-top box configuration. ** Description of the preferred embodiments It is to be noted that in the accompanying drawings, like reference numerals refer to like elements in the several figures. It should further be noted that the term "set-top box" or "STB" as used in the various parts of the description relates to a digital terminal able to receive, decode and possibly to descramble digital signals, for example television and/or radio signals. This kind of terminal is also often designated as "decoder" or "IRD"

(Integrated Receiver Decoder).

Figure 1 shows the general architecture of a system according to the invention in an example comprising only one secondary set-top box 2 connected to a main set-top box 1 via a physical communication link 40. The main STB 1 and the secondary STB 2 both comprise an input 10 / 20 for receiving a digital audio / video signal which is transmitted to a Digital Core module 11 / 21. This module contains a tuner, a demodulator, a demultiplexer, optionally a descrambler for descrambling the received digital data in conjunction with a conditional access module and a smart card (not represented in the figure). The module 11 / 21 further includes an audio / video decoder and a digital-to- analog converter supplying audio / video signals at an output 15 / 25 of the set-top box. This output 15 / 25 is to be connected to a TV set 31 / 32 for the final presentation of the audio / video signal to a user. The main and secondary set-top boxes also include an inter set-top box communication module 13 / 23 in charge of managing the communication between the set-top boxes via the communication link 40 and a Control Unit 12 / 22 controlling the operations of the other modules. The main difference between the main STB 1 and the secondary STB 2 relates in the presence of a modem 14 in the main STB 1 , this modem being used for implementing a return channel allowing the main STB to communicate with the Subscriber Management System of an operator (not represented in the figure). According to the invention, the secondary STB 2 is not equipped with a modem but, as it is able to communicate with the main STB thanks to the communication link 40, it can use the modem 14 of the main STB 1 to communicate with the Subscriber Management System. The way the modem 14 of the main STB is shared between the main STB and all the other set-top boxes present in the household will be described later.

The physical link 40 between main^STB and the secondary STB can be implemented in several ways. In a preferred embodiment, the physical link used for inter decoder communication is the coax cable used for the distribution of the digital television signal to the decoders in the household. This cable is also known as the IFL (Inter-Facility Link) cable. One can refer to an international patent application published under n° WO 04/038965 of the same applicant, Thomson Licensing S.A., to find details of a solution allowing to create a communication channel between several set-top boxes via the coax cable supplying the digital signal to the set-top boxes. An alternative embodiment for the communication path between the set-top boxes consists in the use of the power line modulation technology. The preferred implementation is shown in Figure 2 were the digital television signal is supplied to both decoders via a satellite antenna 5. The antenna 5 is linked to the main STB via a coax cable 41 and to the secondary STB via a coax cable 42. In this embodiment, the inter-STB communication modules 13 and 23 of the main and secondary STB are internally coupled to the inputs 10 and 20 connected to the coax cables 41 and 42. In this implementation, the satellite antenna 5 or the system distributing the digital television signal within the household (the digital television signal can be supplied by cable, satellite or terrestrial transmission) comprises a device allowing the communication of data between the set-top boxes in a particular frequency band as disclosed in the international application n° WO 04/038965 previously mentioned. Thanks to this device, the data transmitted between the decoders, such as "Modem Data", are transmitted on a different communication channel from the one used for transmitting television data to the decoders. In the embodiment of Figure 2, the main STB comprises a PSTN modem 141 which is connected to a phone line 142 of the household. According to the invention, this modem 141 is used either by the main STB 1 when it needs to call back the Subscriber Management System to communicate its caller identifier (corresponding to the phone line 142) or by any secondary STB 2 connected to the main decoder via a communication path when one secondary STB needs to call back the Subscriber Management System to communicate its caller identifier (which will also correspond to phone line 142 of the household).

Figure 3 illustrates an alternative embodiment in which the main STB contains a satellite modem 143. The satellite antenna 5' supplying the digital television signal to the decoders contains in this case a bi-directional LNB (Low Noise Block) to perform the return channel and to send data from the satellite modem 143 to the Subscriber Management System of the operator. ^ . The satellite modem 143 is for example a DVB-RCS (Digital Video Broadcasting, Return Channel via Satellite) modem in which it is necessary to enter the geographic coordinates of the modem during its installation phase. The modem 143 is shared between the main STB 1 and the secondary STB 2 to send regular callbacks to the Subscriber Management System of the operator in order to communicate information of the localization of the modem. By "regular callbacks", we means that the main STB 1 or the secondary STB 2 send callbacks on a periodical basis, for example once a month or once a week, or even more frequently. In a further alternative embodiment, a GSM (Global System for Mobile Communications) modem, a UMTS (Universal Telecommunication Mobile Service) modem or a GPRS (General Packet Radio Service) modem having an associated localization system can be used to send information about the localization of the main STB 1 or the secondary STB 2 to the Subscriber Management System of the operator. We will now describe a protocol implemented in the main STB (Figure 4) and in the secondary STB (Figure 5) in order to manage the share of the modem between decoders. These protocols are carried out in the control units 12 / 22 of the set-top boxes. In a first step 401 , the main STB checks whether it needs the modem to communicate with the Subscriber Management System. If the main STB needs the modem, it allocates the modem to itself (step 402) and performs the communication as needed (step 403). Once the communication is over, the Main STB frees up and de-allocates the modem at steps 404 and 405 for the use by another potential requester. The protocol then goes back to step 401. In case the main STB does not need the modem at step 401 , it will listen to secondary STB requests for use of the modem at step 406. A test is then performed at step 407 to check whether any secondary STB needs to use the modem. If the response to this test is "NO", then the protocol goes back to step 401. Otherwise, in the case where one secondary STB needs the modem, the main STB allocates the modem to this secondary STB (step 408). Then, at step 409, the secondary STB uses the modem of the main STB by transmitting its "Modem Data" through the communication link between both decoders. Once the communication is over, the secondary STB tells the main STB to free up the modem at step 410 and, at step 411, the main STB de-allocates the modem for use by another potential requester. The protocol then goes back to step 401. In Figure 5, the protocol implemented in any secondary STB is shown. At step 501 , a test is performed to check whether: the secondary STB needs to communicate with the Subscriber Management System and therefore needs a modem. If the response to this test is "NO", then the protocol loops on this step 501. If the response is "YES", then instead of using a local modem, it will establish a communication channel with the main STB to request the allocation of the modem (step 502). The secondary STB then waits for the modem allocation at step 503. Once it receives an acknowledgement of its request from the main STB, the secondary STB begins its communication with the Subscriber Management System by using the communication link between main and secondary STB and the distant modem of the main STB as if the modem was local (step 504). Once the communication is over, the secondary STB sends a message to the main STB at step 505 to free up and to de-allocate the modem for use by another potential requester. The main STB is thus in charge of managing conflicts and priorities for the use of the modem. It is also to be noted that in case a secondary STB gets no answer from any main STB at step 503 when it needs a modem, a warning must be reported to the user watching the TV connected to the secondary STB. The state of a STB can be "main" or "secondary". There are at least two ways to configure a STB: - manual configuration, or - automatic configuration. In manual configuration, the subscriber can configure each STB as "main" or "secondary" using a set-up menu. This configuration can also be made optionally at the factory where the STB are manufactured, particularly in case the digital TV operators provide the decoders to subscribers. In automatic configuration, the subscriber just has to check that one of his decoders is equipped with a modem and that it can dialogue with the Subscriber Management System. Each STB can define its state by checking by software the possibility to dialogue with the Subscriber Management System. This can be done, for example, each time the STB is switched on or comes out of stand-by mode. This automatic configuration is shown in the flowchart of Figure 6 where step 601 illustrates the start of the STB followed by a step 602 for checking whether the STB contains a modem. If the response to this test is "NO", then the STB enters "secondary" state at step 605. Otherwise, in case the STB contains a modem (response "YES" to test 602), then a further check is performed at step , 603 to verify whether the modem is able to communicate with the Subscriber Management System. If this check is negative, the STB enters "secondary" state at step 605. Otherwise, it enters "main" state at step 604 and starts behaving as a main STB, detecting the presence of secondary set-top boxes and checking for requests from secondary set-top boxes on the inter-STB communication port. Special care must be taken when the main STB is put in stand-by mode. Either the inter-STB communication module or the modem is still active in that mode, or the user may be warned (by a pop-up message on the display associated with the main STB and/or an icon on the display associated with the secondary set-top boxes) that the modem is unavailable until the main STB is again active.

This concept of modem sharing can be used for other applications than just callbacks to the Subscriber Management System for STB localization verification. It can also be used to offer services than normally require modem connection such as interactive services (pay-per-view, race betting, e-mail, goods/services purchase, ...) or to perform usage control (when operators wish to collect information about channels or services used by the subscriber, this is done though periodic callbacks from the STB to the Subscriber Management System).

The advantages of the invention are as follows: - Ease of installation of multi-STB configurations at the subscriber's premises (no additional phone cable, phone plug, ...); - Lower system cost (no need for a modem in secondary STBs); - Compatibility with existing system at Subscriber Management System level; - Independence from the Middleware and Conditional Access providers; - Easy way to solve conflicts when several STBs want to access the return channel medium.

Claims

1. System for receiving broadcast digital data from an operator, said system comprising a main terminal (1) containing a modem (14, 141, 143) and at least one secondary terminal (2) linked to the main terminal via a communication link (40), characterized in that the at least one secondary terminal is able to use the modem of the main terminal to communicate information about its localization to the operator.

2. System according to claim 1 , characterized in that the communication link between said main terminal (1) and said at least one secondary terminal (2) is adapted to use a link (41, 42) for supplying said broadcast digital data to said terminals.

3. System according to claim 1 or 2, characterized in that said main terminal (1) comprises means (12) for managing the share of the modem between said terminals.

4. System according to one of the preceding claims, characterized in that the modem is a Public Switched Telephone Network modem (141) intended to be connected to a phone line of a house in which said terminals are located.

5. System according to one of claims 1 to 3, characterized in that the modem is a satellite modem intended to be connected to a satellite antenna (5') having bi-directional communication means, said satellite modem being able to communicate its geographic coordinates to the operator.

6. Digital terminal (1) for receiving broadcast digital data from an operator, said digital terminal containing a modem (14, 141, 143), characterized in that the digital terminal is able to be linked to at least one secondary terminal (2) via a communication link (40) and in that the digital terminal comprises means (12) for managing the share of the modem (14, 141, 143) between said terminals in order that said terminals be able to communicate information about their localization to the operator.

7. Digital terminal (2) for receiving broadcast digital data from an operator, said digital terminal being adapted to be linked to one main terminal (1) containing a modem (14, 141, 143), characterized in that the digital terminal (2) is adpated to use the modem of the main terminal (1 ) to communicate information about its localization to the operator.

8. Method for managing access to a modem (14, 141, 143), said modem being contained in a main terminal (1 ) and being adapted to be used by the main terminal or by at least one secondary terminal (2) linked to the main terminal, characterized in that the method comprises the steps, at the main terminal (1), of: checking (401) whether the main terminal needs to use the modem; and in case the main terminal needs the modem, allocating (402) the modem to the main terminal; in case the main terminal does not need the modem, checking (407) whether any secondary terminal linked to the main terminal needs to use the modem; and in case one secondary terminal needs the modem, allocating (408) the modem to this secondary terminal.