EP1903696A1

EP1903696A1 - Navigation system with broadcast receiver and mobile terminal for using restricted-access multimedia content

Info

Publication number: EP1903696A1
Application number: EP06425653A
Authority: EP
Inventors: Piero De La Pierre
Original assignee: Magneti Marelli Sistemi Elettronici SpA
Current assignee: Marelli Europe SpA
Priority date: 2006-09-25
Filing date: 2006-09-25
Publication date: 2008-03-26

Abstract

A system and a method for using restricted-access multimedia content broadcasting services are described.

The use of the services is performed by means of a multimedia device such as, for example, a portable navigation device (N), a device for reproducing portable multimedia content, or a portable play station or console. The use of the restricted-access services is performed by means of decoding of the broadcasting signals received, using an access code which is made available by means of a communication session with an external mobile radio terminal (T) which is present within a predetermined communication operating range and is adapted to acquire this code from an associated recording medium.

Description

The present invention relates in general to restricted-access multimedia content broadcasting systems, such as, for example, digital audio and video broadcasting services.
Specifically, it relates to a system for using restricted-access broadcasting services and in particular a system for receiving them on-board vehicles.
The development of digital audio and video broadcasting technology is at present accompanied by the spread of restricted-access multimedia content broadcasting services. Typically, a person wishing to use such services must acquire the rights for access thereto and receive one or more access codes which are stored on a recording medium (such as, for example, a smart card) and which allow decoding of the broadcast signals, which is otherwise illegible.
In general, therefore, every receiver apparatus for decoding and displaying to the user restricted-access multimedia content must have a device for reading a recording medium which contains the subscriber access code.
Digital video broadcasting services have recently found, in portable mobile radio terminals, a medium suitable for their spreading among a large number of consumers.
Mobile radio terminals are already designed to read a recording medium (SIM) which has, stored inside it, the identifier of the person subscribed to the telephone services, and the code for accessing the broadcasting services supplied by the telephone operator may also be stored on this medium.
The screen of the mobile radio terminals is suitable - albeit with some limitations due to its small size - for use as a screen for the display of video multimedia content broadcast via a large number of digital land television channels.
However, other electronic accessory or amusement devices which are provided with complete user interfaces (screens, microphones, keyboards or joysticks) and which are potentially suitable for displaying broadcast multimedia content are widely available commercially.
Consequently these devices could also potentially be equipped with a device for reading a recording medium storing the code allowing access to the restricted-content broadcasting services which may be supplied by a telephone operator.
This is technically possible, albeit with an increase in the cost of the final product, but has the drawback of requiring duplication of the media for recording the access code or the continuous displacement of the said media between the various devices which a user possesses and intends to use alternately, to the detriment of simple use of the services.
The object of the present invention is therefore to provide a system for using restricted-access multimedia content broadcasting services which overcomes the drawbacks of the known art mentioned above, namely which may be provided on any multimedia device possessed by a subscribed user, making the content accessible in the simplest possible manner, using a single medium for storing the access code.
According to the present invention, this object is achieved by means of a system having the characteristic features included in Claim 1.
Particular embodiments form the subject of the dependent claims.
The invention also relates to a method for using restricted-access multimedia content broadcasting services according to Claim 23.
In brief, the present invention is based on the principle of using, as remotely located readers, devices which already comprise a reader for a recording medium (smart card or the like) containing a code for access to the restricted-access broadcasting services, initiating a session for secure transmission of this code to separate multimedia devices which are specifically enabled to receive the service and display it to the user and do not possess this reader.
The device including a recording medium containing the code for access to these services is typically a mobile radio terminal.
The device enabled to receive the multimedia content broadcasting service and for displaying it to the user may be a portable navigation device, a portable device for reproducing multimedia content, a portable play station or console, or a telematic entertainment and information system installed on-board a vehicle.
In particular, with reference to the automotive sector, an on-board satellite navigation device may be adopted as a device which is able to receive a multimedia content broadcasting service and show this content to a user and able to be configured for automatic selection of these services on a geographical basis.
Further characteristic features and advantages of the invention will be explained more fully in the detailed description which follows, provided by way of a non-limiting example, with reference to the accompanying drawings, in which:

Figure 1 is a simplified block diagram of an embodiment of a system according to the invention; and
Figure 2 is a schematic illustration of the operating stages of the system.

With reference to the Figures, these show a navigation apparatus N, for example an apparatus which is portable or installed on-board a vehicle, including - as shown in the enlarged detail - a module R for receiving multimedia content broadcasting signals, provided with a dedicated antenna A, and an associated decoder module D arranged to perform decoding of the signals received from the receiver module R. The navigation apparatus is equipped with its own display screen S and is adapted to operate as a multimedia device for displaying on the screen multimedia content conveyed by the decoded signals.
A multimedia content broadcasting service may be selected depending on the commands introduced by the user via an input interface K (for example, a plurality of keys) which is normally designed to perform the usual command functions of the apparatus.
An external mobile radio terminal T, for example an ordinary cellular phone, is arranged within a predetermined operating range of a communications link L with said navigation apparatus N and is provided with means for acquiring a code for accessing multimedia content broadcasting services, for example a reader for a recording medium C (such as a SIM card, shown in the figure in the extracted condition) which has said code stored on it.
The navigation apparatus N comprises a short-range communication interface adapted to establish a communication link L with the mobile radio terminal T and establish a secure communication session with said terminal in order to acquire the code for access to the broadcasting services so as to make this code available for the decoder module D.
The communication link L between the navigation apparatus N acting as a multimedia device and the mobile radio terminal T may be a wireless connection which is able to ensure the secrecy and integrity of the code, for example using a Bluetooth protocol or a Wi-Fi protocol, or a wired connection, for example comprising a serial communications line or a bipolar power line.
The navigation apparatus N acting as a multimedia device is arranged for transmitting a signal interrogating mobile radio terminals which are active within a predetermined communication range, for example of an order of magnitude equivalent to the dimensions of the vehicle in which the apparatus N is installed, or its passenger compartment, when the receiver R receives an encoded multimedia content broadcasting signal.
If the presence of the mobile radio terminal T is detected, the apparatus N automatically establishes a communication link L with the abovementioned terminal and carries out a mutual authentication procedure. Preferably, it initiates an encrypted communication session with the mobile radio terminal, where the encryption key is derived from the broadcasting signal received, as shown in Figure 2.
Conveniently the system is arranged to cause termination of the communication session if the communication link L with the mobile radio terminal T is interrupted, for example as a result of the terminal being moved out of the operating range of the link or owing to the credit available for the active service being used up, so as to prevent any fraudulent use of the service.
With reference to Figure 2, a preferred mode of operation of the system is described.
Upon switching on the receiver R, the latter is tuned by means of the interface K so as to receive predetermined audio/video channel stations. The stations may be encrypted by the restricted-access codes. In particular, the actual transmission may be encrypted in one geographic zone and be transmitted unscrambled in other zone, depending on the marketing policies of the broadcasting station.
The receiver which receives an unscrambled transmission checks that there are no geographical area restrictions.
If the receiver R detects that it is tuned to a coded audio/video channel, it searches for the access code, attempting to establish connection with a mobile radio terminal T in the vicinity. If a terminal is detected, the receiver exchanges mutual authentication credentials with the terminal and after authentication has been successfully completed, it establishes a restricted-access session with transfer of the access codes from the mobile radio terminal to the receiver. The protocol used for transfer of the codes is secure so as to ensure that fraudulent acquisition of the codes is technically improbable.
Once the access codes have been received, the decoder associated with the receiver is able to decode the content and make it available in legible form.
For secure transmission of the access codes it is envisaged using a transmission algorithm which is based on a combination of a public key / private key algorithm with a symmetrical key. The public key is obtained by the receiver R via the broadcast transmission, while the private key is instead obtained by the mobile radio terminal T via a channel which is normally made secure by the telephone operator using the same techniques used for enciphering SMS messages.
Upon connection, the mobile radio terminal T transmits to the receiver an index and a test number to be encoded. The receiver carries out on the test number a conversion using the public key and returns the result to the mobile radio terminal.
The mobile radio terminal, in the event of a correct response, provides the receiver with a symmetrical session key by means of which it will encode the entire subsequent transmission of the access code.
The public key / private key pair may be modified with a high frequency (for example, every 15 minutes) in order to prevent the access codes being revealed even in the event of unauthorized access.
In the example described of a preferred embodiment, in which the "extemporary" multimedia device is a navigation apparatus including satellite locating means able to determine the geographic location of the device, the receiver R may be conveniently arranged to filter the broadcasting signals received depending on the geographic location detected or else decide whether or not to acquire an access code depending on the geographical location detected.
Said receiver may be used as a DVB-H digital television connecting it to a special decoder by means of the SD slot or other available channel (USB, etc.). In order to access the DVB-H channels which are broadcast in restricted-access (CA) mode, the navigation apparatus makes use of the access codes contained in a SIM card which is supplied by the telephone operator which transmits the channel and which is housed in the mobile radio terminal to which connections are made via the Bluetooth channel, being already available for other purposes both in the navigation apparatus and in the mobile radio terminal.
Finally, in order to allow varying service policies depending on the geographical area, the transmission of given contents may contain a code which indicates whether reception is prohibited in particular geographic zones.
Upon reception of the geographic prohibition codes, the receiver checks whether its own position (supplied to it by the satellite locating system with which it is associated) is situated in one of the prohibited zones, in which case it does not request the restricted-access codes from the mobile radio terminal.
Obviously, without modifying the principle of the invention, the embodiments and the constructional details may be widely varied with respect to that described and illustrated purely by way of a non-limiting example, without thereby departing from the scope of protection of the present invention defined by the accompanying claims.

Claims

System for using restricted-access multimedia content broadcasting services, comprising:
- means (R) for receiving multimedia content broadcasting signals;

- decoding means (D) associated with said receiving means (R) and adapted to perform decoding of said signals based on a predetermined code for access to said services; and

- presentation means (S) associated with said decoding means (D) and adapted to provide a user with the multimedia content conveyed by the decoded signals;
characterized in that it comprises means for communication with at least one external mobile radio terminal (T) present within a predetermined communication operating range and provided with means for acquiring said access code from an associated recording medium, which communication means are arranged to initiate a communication session with said mobile radio terminal (T) for acquisition of the access code, and supply said code to the means (D) for decoding said broadcasting signals.
System according to Claim 1, in which said communication means are secure communication means.
System according to Claim 1 or 2, in which said means for acquiring the access code comprise means for reading a recording medium having said code stored on it.
System according to any one of the preceding claims, in which said communication means are arranged to transmit a signal for interrogating mobile radio terminals (T) which are active within said predetermined range of communication when said receiving means (R) receive coded multimedia content broadcasting signals, and to establish automatically a communication link (L) with the abovementioned terminal (T) if its presence is detected.
System according to Claim 4, in which said communication means are arranged to carry out a mutual authentication procedure with the abovementioned mobile radio terminal (T).
System according to Claim 4, in which said communication link (L) is a wireless connection.
System according to Claim 6, in which said communication link (L) is a connection using a Bluetooth protocol.
System according to Claim 6, in which said communication link (L) is a connection using a Wi-Fi protocol.
System according to Claim 4, in which said communication link (L) is a connection of the wired type.
System according to Claim 9, in which said communication link (L) comprises a serial communications line.
System according to Claim 9, in which said communication link (L) comprises a bipolar power line.
System according to Claim 6 or 9, in which said communication means are arranged to establish an encrypted communication session with the abovementioned mobile radio terminal (T), in which the encrypting key is derived from the broadcasting signal received.
System according to Claim 12, in which said decoding means (L) are designed to cause termination of the reception of said broadcasting service if the communication link (L) with the mobile radio terminal (T) is interrupted.
System according to any one of the preceding claims, in which said means for presenting multimedia content to a user comprise a main multimedia device (N) associated with said receiving means (R) and including said means for communication with at least one mobile radio terminal (T).
System according to Claim 14, in which said main multimedia device (N) comprises a user interface device (K) adapted to receive commands from the user and is adapted to select a multimedia content broadcasting service depending on the commands introduced by the user via said interface device (K).
System according to Claim 14 or 15, in which the main multimedia device is a navigation device (N), including satellite locating means adapted to determine a geographic locating position of the device.
System according to Claim 14 or 15, in which the main multimedia device is a portable device for reproducing multimedia content.
System according to Claim 14 or 15, in which the main multimedia device is a portable play station or console.
System according to Claim 16, in which said receiving means (R) are designed to filter the broadcasting signals depending on the geographic locating position detected.
System according to Claim 16 or 19, in which said communication means are arranged to determine the acquisition of an access code depending on the geographic locating position detected.
System according to Claim 14 or 15, in which the main multimedia device is an entertainment and information unit installed on-board a vehicle.
System according to Claim 21, in which said communication operating range has an order of magnitude equivalent to the dimensions of the vehicle or its passenger compartment.
Method for using restricted-access multimedia content broadcasting services by means of a main multimedia device (N) in which the following are performed:
- reception of multimedia content broadcasting signals;

- decoding of said signals using a predetermined code for accessing said services; and

- presentation, to a user, of the multimedia content conveyed by the decoded signals;
characterized in that it comprises establishing a communication session between said main multimedia device (N) comprising means (R) for receiving said content, and at least one external mobile radio terminal (T) present within a predetermined operating range for communication with said main multimedia device (N) and provided with means for acquiring said access code from an associated recording medium.
Method according to Claim 23, in which the initiation of a communications session comprises:
- interrogating mobile radio terminals (T) active within a predetermined range of communication upon reception of coded multimedia content broadcasting signals by the main multimedia device (N);

- establishing a communication link (L) with a terminal (T) present within said range of communication;

- carrying out a procedure of mutual authentication between the main multimedia device (N) and the mobile radio terminal (T);

- initiating an encrypted communications session with the abovementioned mobile radio terminal, in which the encrypting key is derived from the broadcasting signal received.
Method according to Claim 24, comprising the termination of decoding of the broadcasting signals received if the communications link with the mobile radio terminal (T) is interrupted.
Method according to any one of Claims 23 to 25, comprising filtering of the broadcasting signals depending on the geographic locating position detected by a satellite locating device associated with said main multimedia device (N).
Method according to Claim 26, comprising the decision of acquiring an access code depending on the geographic locating position detected.