Method of initialisation of a link between a mobile station and a domestic base station

The present invention relates to a method of initializing a link between a mobile terminal of a public mobile network and a domestic base station, eg a base station of a public switched network.

The invention also relates to an initialization service such binding.

The invention relates to the field of wireless telephony. Wireless telephone systems (CTS acronym of the English expression "cordless telephony systems") currently existing are available as handsets or terminals and base stations with limited range radio link, such as limited domestic use in an apartment or house. It is possible, in the future, such as telephone systems operate in frequency bands already covered and used by public mobile network operators. This poses a problem of frequency management.

Another problem is the management of links security settings between handsets and base stations.

Yet another problem is the proliferation of mobile handsets; a subscriber may have a mobile handset to a public mobile network, and a handset for a cordless phone. GB-A-2282735 mentions that it was suggested to use the same handset for the public mobile network and the public switched network. This document also mentions that this solution is not advantageous due to complications resulting from frequency management necessary to prevent interference between different home base stations or devices necessary to prevent such interference, for example by dynamic allocation canals.

Using a single handset for the mobile public network and a domestic base station is proposed for example in the GSM CTS system being standardized. A feature of this system is the one or more subsets of frequencies used for communication between a home base station and the mobile terminal for the single public mobile network and used for communication with a home base station.

The use of a dynamic channel allocation scheme, as suggested in GB-A-2282735 requires that the home base station and the mobile terminal are initialized with the same parameters, and for example have the same frequency departure and the same frequency changing algorithm. One solution to this problem is to initialize the mobile handsets and home base stations with the same parameters; This prevents individual allocations of channels, as well as a dynamic channel allocation; This further prevents sold separately domestic base station and handset.

GB-A-2,282,735 provides an automatic routing device of calls to a handset unit of a public mobile network or to the conventional switched telephone network, depending on the distance between the portable handset and a home base station; This document proposes to automatically route calls to the PSTN when the handset is near the base station; the proximity of the handset is detected through the issuance by the combined low-power telemetry signals and narrowband. This solution does not solve the problem of multiplicity of handsets or the frequency management problem by extending the frequency of mobile public networks.

US 5668875 describes a terminal communicating with a base station by sending the subscriber identity between the terminal and the base station once the link between the terminal and the base station has been established.

WO 9709834 discloses a mobile phone capable of operating either with a public cellular network or with a private radio network, as well as means allowing the phone to automatically switch on one or the other of the two networks as to as the user moves with his phone.

The invention therefore provides a solution to manage settings for wireless telephone systems, which allows to use the same handset for connection to a public mobile network and for connection to a home base station. It still allows a network operator to control the connections settings with home base stations.

It also solves the problem of new initialization domestic base stations in mobile telephone systems using the same handset.

It even solves the new problem of the variation in time of the position of domestic base stations, and allows monitoring over time connection parameters allocated to domestic base stations.

The invention has the advantage of allowing connections parameter management with domestic base stations by a mobile public network administrator. It allows to sell separately the mobile terminals and base stations. It provides an authentication of the mobile terminal as the base station with good security.

More specifically, the invention provides a method of initializing a link between a mobile terminal of a public mobile network and a domestic base station communicating with each other by a telephone link of the public mobile network different from the connection to be established, including<ul><li>authentication of the mobile terminal by the public mobile network;</li><li>transmission to the terminal from the public mobile network initialization data to the connection with the home base station; and</li><li>- The transmission of such data from the mobile terminal to the home base station on a separate link of the link to be established,</li><li>establishing the connection between the home base station and the mobile terminal.</li></ul>

In one embodiment, the method further comprises a calling step by the mobile terminal to a special service number, before the authentication step.

Advantageously, the link initialization data depends on the location of the mobile during the authentication step.

In another embodiment, the initialization data includes time information.

The authentication step may include authentication of the mobile normal by the public mobile network. It may also include the transmission by the mobile information required for link initialization, such as the type of home base station.

In one embodiment, the communicating step from the mobile comprises storing initialization data in a smart card of the mobile terminal and the introduction in a playback device of the home base station of said card chip.

In another embodiment, the communicating step from the mobile comprises transmitting data from the mobile terminal to the base station on a separate link of the link to be set. This separate link may be a contactless link, such as an infrared link or a microwave link for contactless cards.

Before the data transmission from the mobile stage, the method can include an authorization step of transferring given.

The home base station is for example a terminal of a public switched network or a terminal of a PBX.

It finally relates to a cordless telephony system comprising a domestic base station and a mobile terminal of a mobile public network communicating with each other by a telephone link of the mobile public network, characterized by a connection between the base station and the terminal , separate from said telephone link, said mobile terminal comprising means for authenticating the mobile terminal by the mobile public network, said mobile terminal comprising means for transmitting to the terminal from the public mobile network of link initialization data with the private base station, said mobile terminal comprising means for transmitting initialization data from the mobile terminal to the domestic base station, on a separate link of the link to be set, and means for establishing the link, separate from said telephone link between the home base station and the terminal mobile.De preferably, the separate link is a contactless link, such as an infrared link or a microwave link for contactless cards.

Other characteristics and advantages of the invention will appear on reading the following description of the invention embodiments, given by way of example only, and with reference to the case of GSM CTS.

In this case, the goal is to establish a link between a mobile terminal of a public mobile network, ie GSM, and a base station connected for example to a public switched network. As explained above, such a bond allows to use the same handset, firstly on the public mobile network, and on the other hand, close to the home base station over the public switched network.

The invention proposes that the initialization data link, such as particular frequencies or channels to be used for establishing the connection, the start frequency, the law of variation in the frequency, or the maximum authorized power or generally other useful parameters to the link are transmitted to the mobile terminal from the public mobile network; these data are for example transmitted by the operator of public mobile network, which can manage the frequencies used locally by the mobile terminals; this data can also be transmitted from the mobile network by another speaker that the operator.

Transmitting data from the public mobile network allows to use authentication of the mobile terminal, for example in the case of GSM network using authentication procedures.

We now give an example of implementation of the invention in a GSM CTS. A mobile terminal wishing to establish a connection to a home base station connects to the service, for example by calling a fixed or given service number. Permission to link establishment may be granted in various ways: for example, the mobile terminal in question can be recorded by the operator or service as an authorized user to establish such a link; it is also possible to provide a mobile terminal a special smart card that only allows the call service in question or provided on the smart card of the user permission to establish a connection; it is also possible that the service providing the initialization data presents a special number that is accessible with a special smart card; we can still provide a password, or any other appropriate procedures.

Once the connection with the service, the terminal is identified, using the authentication procedures of the public mobile network, with the safety associated with these procedures. Avoids the security problems of the initialization procedures of the prior art.

The information needed to determine the link initialization data can be stored on the smart card terminal to be transmitted to the service; they may also be provided by the subscriber using the terminal, or be provided by the service operator; it is also possible to obtain them directly from the subscriber when it requests a subsequent business permit an affair. Thus, the position information of the mobile terminal when requesting establishment of a link are typically provided by the public mobile network according to the network cell in which the terminal is located; the type of home base station with which the connection is established can for example be provided by the customer as a code at the time of establishing the connection with the service.

The data needed to link initialization can then be transmitted to the terminal from the public mobile network, possibly with a time stamp or seal, as explained below; these data are stored in the smart card of the subscriber. Data transmitted from the mobile terminal are then transmitted from the mobile terminal to the base station, so as to then allow the establishment of the link; Indeed, after this step, the mobile terminal and the home base -station both have initialization data. This stage of transmission can be done in various ways; ideally, this transmission step is at least as secure as the step of authenticating the mobile terminal.

In the case of GSM, the link initialization data may advantageously be stored in the chip card (SIM) of the mobile terminal, or in a specific map dedicated to the establishment of the connection with the private base station ; data transmission to the home base station can then be carried out simply by introducing the corresponding SIM card in a reading device of the home base station. This then requires simply to provide on the home base station a card reading device chip.

In one case as in the other, it is not necessary that the home base station is in an area covered by the public mobile network.

The necessary initialization data may be contained in the SIM card of the mobile terminal and transferred to the base station via the SIM card, providing a card reader in the base station, as explained above. It is still possible to provide for other methods of transferring the link initialization data between the mobile terminal and the home base station. It is thus possible between the mobile terminal and the home base station a separate cable, without contact. Examples of such links are infrared links or microwave links for contactless card reading.

The operation of the invention in this case is for example the following. The base station detects the presence of a mobile terminal; in the case of an infra-red link, this detection can be achieved if the user approaches the base station terminal, and the transmitter has infrared receiver of the terminal opposite to that of the base station. In the case of a microwave link, the base station may detect the presence of a smart card nearby.

After detecting the presence of a mobile terminal, the base station sends to the mobile terminal a request initialization data on the separate cable. This request is received by the mobile terminal. It can be provided in this case that the mobile terminal transmits the necessary information to the base station on the user's permission; for example, the transfer of data to the base station may only be allowed on entry into the mobile terminal of a confidential code or any other user authentication process on the mobile terminal. If permission is given, or if authorization is not required, the donnéees necessary for initialization are transmitted from the mobile terminal to the base station, on separate cable. The connection between the base station and the mobile terminal can then be established.

Such an embodiment avoids the user any additional action other than where appropriate a request for authentication; service is then available without the user having to insert his card into the home base station. It also avoids problems that might arise if the user forgets the card in the base station.

In addition, it is clear that this embodiment can be understood regardless of the origin of the data needed to initialize the connection between the mobile terminal and the base station. The data transfer from the mobile terminal to the base station, by moving a SIM card or on a separate link is used whenever the mobile terminal enters the coverage area of ​​the home base station; the initialization data are not necessarily updated from the public network each time the terminal enters the coverage area. The data could also be stored in the card of the mobile terminal, and will not be updated from the public mobile network.

In the case where data is transmitted from the public mobile network, to enable use of the initialization data in a limited geographical area, the initialization data can be transmitted with a time stamp or a seal; it is possible for the home base station to know when the initialization data has been received by the mobile terminal. One can not allow the establishment of the connection only if the initialization data is sent to the home base station in a given time interval after receiving them, or if the link is established for the first time in a given time interval after receiving the data. This ensures a limitation of movement of the mobile from the moment it receives the data and when these data are transmitted to the home base station. In this way, the initialization data of the link, and for example the channels allocated to the connection, are used in a geographical area controlled by the network operator.

If the base station is moved, its power is turned off and this can be used to indicate a base of the connecting motion requiring a new initialization procedure of the connection to the new location of the base station, if necessary with new parameters; thus, the invention allows a dynamic management of different initialization data connections implemented by moving the public mobile network.

It is clear that the invention can sell separately mobile devices and home base stations, and allows changing as each other; it also allows the initialization of several bonds with different base stations, in different places. It also enables a base station to be initialized and to establish links with various mobile devices.

From the perspective of the network operator or the authority managing the allocation parameters for connections between mobile devices and home base stations, the invention can provide a link management service. This service includes a step of transmitting to the mobile terminal from the public mobile network of link initialization data, after a step of authenticating a mobile terminal by the mobile public network. As explained above, this authentication step can be performed by simply using the network authentication capabilities, such as GSM. This can be done after a call from the mobile to a given number of the mobile public network.

The procedure to establish the link, once the mobile terminal and the base station have initialization data are known to the skilled person and can be easily implemented; it is the same for the recognition by the home base station to the proximity of the terminal; may for this purpose be made to the methods mentioned in GB-A- 2282735.

Of course, the present invention is not limited to the examples and embodiments described and shown, but is capable of numerous variants accessible to the skilled person. We might as well use other types of networks as GSM or the public switched network.