WO1999057928A1

WO1999057928A1 - Cellular network mobile telephone, capable of being used as domestic wireless telephone handset

Info

Publication number: WO1999057928A1
Application number: PCT/FR1999/001031
Authority: WO
Inventors: Rafaël Alos; Pierre Nicaise
Original assignee: Sagem S.A.
Priority date: 1998-04-30
Filing date: 1999-04-30
Publication date: 1999-11-11
Also published as: EP1075772A1; AU3609299A; FR2778302B1; FR2778302A1

Abstract

The invention concerns a mobile telephone designed for communicating through said cellular network (101) and comprising means matching with a wireless telephone private base (30) designed to communicate through another telephone network (100). The mobile telephone (20), thus designed to operate either in cellular mode, or in private mode as a wireless telephone handset apparatus, comprises means (1, 17) for selecting one of the two modes, cellular or private. The means for communicating through the cellular network comprising means for the telephone to be authenticated by the cellular network, the selection means are designed, when the private mode is selected, to inhibit the means for the telephone to be authenticated by the cellular network.

Description

1

MOBILE TELEPHONE OF A CELLULAR NETWORK FOR USE AS A WIRELESS TELEPHONE FOR USE

DOMESTICATED

The field of the invention is that of mobile telephony.

In mobile telephony, there are essentially two types of telephone.

The first type of telephones are cordless telephones for private and domestic use, comprising a base and at least one mobile handset paired with the base. The base is connected to a telephone network, the PSTN switched telephone network for example, generally by wired link, and the mobile handset is connected to the base by radio link.

The second type of telephone is arranged to communicate via a cellular telephone network of base stations, generally by radio link. As an example of cellular networks, mention may be made of GSM networks, DCS 1800, etc.

To make a cellular network mobile phone operational, it is generally advisable to introduce a card supporting an electronic chip there, it is generally a standard SIM card, containing authentication data of the telephone through which the network cellular is capable of controlling the access of the telephone to the cellular network so as, in particular, to bill its communications. Without a SIM card, the phone cannot be used.

A cellular network mobile phone offers great freedom of movement, as the cellular network has extensive geographic coverage, while wireless phone usage is limited to the vicinity of the base. On the other hand, for cost reasons, it may be more advantageous, in the vicinity of the base of the cordless telephone, to use it in order to go through the network to which it is connected, rather than by a cellular network.

The invention proposes to take advantage of the specific advantages of wireless telephony, which are essentially cost advantages, as well as of those of cellular telephony which essentially reside in mobility, in a simple manner. 2

To this end, the invention relates to a mobile telephone of a cellular network comprising means for corιτrnu-- quer through said cellular network, comprising means of pairing to a private base of wireless telephone arranged to communicate through a telephone network and, the mobile telephone being thus arranged to operate either in cellular mode, or in private mode like telephone handset of the cordless telephone, means of selection of one of the two modes are provided, cellular and private, telephone characterized by the fact that the means for communicating through the cellular network comprising means for authenticating the telephone by the cellular network and the selection means are arranged, in the case of selection of the private mode, to inhibit the authentication means of the telephone through the cellular network.

The telephone can be used either, in a conventional manner, in cellular mode and, in this case, one passes by the cellular network, or in private mode, like handset of cordless telephone domestic and, in this other case, one passes by the wireless phone network. Thanks to this, in the vicinity of the base of the cordless telephone, one can switch to private mode in particular in order to take advantage of the lower cost of communications through the cordless telephone network.

In private mode, the mobile telephone in the cellular network functions as an ordinary telephone handset associated with the base of the cordless telephone. The mobile phone is transformed into a cordless telephone telephone handset.

In a particular embodiment, the base pairing means comprise means for authenticating the mobile phone by the base.

This avoids the risk of a malicious third party using the database without being authorized to do so.

Preferably, the telephone comprises means for executing an initial identification registration protocol with the base.

Advantageously, the mobile telephone includes means for, if necessary, notifying the cellular network of the selection of the private mode. 3

More preferably, the means of authentication by the cellular network comprise a support card for a memory for storing authentication data.

By inhibiting the authentication means, the telephone is made usable with or without an authentication card, whereas in the prior art it was only operational with this card.

The invention finally relates to a pairing method between, on the other hand, a mobile telephone, such as that presented above, arranged to communicate through a telephone, cellular network, and, on the other hand, a private base. , a cordless telephone arranged to communicate through another telephone network, process during which the mobile telephone identifies itself with the base which controls the access of the mobile telephone to said other telephone network, process characterized in that at during an initial registration step, the mobile telephone registers its identity with the base and the base assigns to the mobile telephone a secret encryption key.

The invention will be better understood with the aid of the following description of the mobile telephone and of the cordless telephone base, according to a particular embodiment of the invention, and of a particular embodiment of the method of invention, with reference to the attached drawing in which:

- Figure 1 shows a functional block diagram of the mobile phone, according to the particular embodiment;

FIG. 2 represents a functional block diagram of the base according to the particular embodiment and

- Figure 3 shows a diagram of the mobile telephone, the private base and two telephone communication networks.

The mobile telephone 20 is intended to communicate through a cellular network 101, in this case a GSM network, comprising a plurality of base stations.

The mobile telephone 20 comprises, in a conventional manner, a human-machine interface comprising an input keyboard 1, a display screen 2, a microphone 3, a loudspeaker 4 and a memory 5 containing human interface software. machine comprising in particular menus and commands intended to be displayed on the display screen 2. 4

The loudspeaker 4 is connected to a decoding block 6 for digital / analog conversion, itself connected to a channel decoder 7 for the selection of a communication channel. The microphone 3 is connected to a coder 8 for analog / digital conversion, itself connected to a channel coder 9 for the selection of a communication channel.

The encoder 7 and the decoder 9 are respectively connected to a radio reception block 10 and to a radio transmission block 11, both connected to a radio antenna 12. The reception block 10 and the transmission block 11 have two operational radio frequencies, one specific to cellular telephony for use of the telephone in cellular mode, and the other specific to wireless telephony for use of the telephone in private, domestic mode, as will be explained below.

A control block 15, to which all the elements of the mobile telephone 20 are connected, is provided for controlling the operation of the mobile telephone 20.

The mobile telephone 20 also comprises a housing for receiving a support card for an electronic chip, in this case a standard SIM card 13, and connectors 16 for connecting the chip to the telephone, and more precisely to a switch. 17, explained below. The chip contains in memory authentication data of the mobile telephone 20 by the cellular network 101, an authentication protocol by the cellular network 101 and a GSM communication protocol.

In addition, the mobile telephone 20 comprises a memory block 14 containing authentication data of the mobile telephone 20 by the private base 30 of FIG. 2, a pairing protocol with the base 30, a communication protocol with the base 30 , in this case the standard wireless telephony protocol CT2, and an initial registration protocol for identification with the base 30. The pairing protocol comprises an encryptor, an encryption program using an encryption key.

Finally, the memory 14 and the electronic chip of the SIM card 13 are connected to the control block 15 with the interposition of the switch 17 which is a switch with two positions: a cell mode position and a private mode position. In the cellular mode position, the switch 17 connects the electronic chip of the SIM card 13 to the control block 15, via the connector 16, and, in the private mode position, it connects the memory 14 to the control block 15 thereby inhibiting the SIM card 13. The input keyboard 1 comprises two keys for selecting cellular mode and private mode respectively, under the control of which the switch 17 switches either to the cellular mode position or to the private mode position, and a key for activating the protocol d initial identification registration with base 30.

The mobile telephone 20 is thus arranged to operate either in cellular mode, in other words in a conventional manner by radio link with the cellular network 101, and more precisely by radio link with a base station of the cellular network 101, or in private mode, by air link, here radio, with the private base 30, as will be more precisely explained below.

The private base 30 is a home cordless telephone base, intended to be paired with a cordless telephone handset. The term "cordless telephone" is intended to denote the assembly comprising the domestic base 30 and the telephone handset connected to each other by air link, here radio.

The cordless telephone is arranged to communicate through a telephone network 100 other than the cellular network 101 of the mobile telephone 20, in this case the switched telephone network PSTN 100.

The base 30 includes a line interface 31 connected on one side to the PSTN network 100, by wire link, and on the other side to a codec 32 comprising an analog / digital conversion encoder 33 and a digital / analog conversion decoder 34 .

The base 30 also comprises a channel switch matrix 35 comprising an encoder 36 for channel selection for radio transmission and a decoder 37 for channel selection for radio reception, the base 30 here comprising eight channels, or time channels , and a communication between the base 30 and a telephone handset using one of the eight time channels.

The routing matrix 35 is connected to a radio transmission / reception unit 38 comprising a radio transmitter 39 connected to the encoder 36 and a radio receiver 40 connected to the decoder 37. A radio antenna 41 is connected to the transmission / reception unit radio 38.

The base 30 further comprises a memory block 42 containing an initial registration protocol for identifying the mobile telephone 20, a protocol 6 for pairing with the mobile telephone 20, authentication data for the mobile telephone 20 and a wireless telephone communication protocol, in this case the standard protocol CT2. The pairing protocol includes an encryption program, identical to that of the mobile telephone 20.

Finally, a control block 43 is provided to which all the elements of the base 30 are connected, and intended to control the operation of the base 30.

After the structural description of the mobile telephone 20 and the base 30, their operation will now be described.

Initial registration of identification of mobile phone 20 by base 30

To communicate through the PSTN network 100, via the private base 30, with the mobile telephone 20, the mobile telephone 20 must first identify and register with the base 30. For this, the user of the cordless telephone presses the key for activating the initial registration protocol with base 30, and brings the mobile telephone 20 close to base 30.

The mobile telephone 20 and the base 30 dialog with each other and, during this dialogue, execute the initial identification recording protocol of the telephone 20 by the base 30.

It will be recalled here that the mobile telephone 20 and the base 30 communicate with each other by radio link, at a radio frequency specific to wireless telephony, the blocks 10 and 11 for radio reception and radio transmission of the telephone. mobile 20 and the transmit / receive block 38 of the base 30 using a radio frequency specific to wireless telephony. For confidentiality reasons, the registration procedure is carried out at low power.

During the recording, the mobile telephone 20 provides the base 30 with its identity, contained in the memory 14, and the latter assigns to it in return a secret identification key, constituting an encryption key. The identity and the secret identification key of the telephone 20 are recorded in the memory block 14 of the mobile telephone 20 as well as in the memory block 42 of the base 30. 7

The mobile telephone 20 thus contains, in its memory block 14, its identity associated with the secret identification key allocated by the base 30, the identity and the secret key constituting authentication data of the telephone 20 by the base 30. Similarly, the base 30 contains, in its memory block 42, the identity of the mobile telephone 20 associated with the secret key which has been allocated to it.

Mobile phone operation in cellular mode

To communicate through the cellular network 101, a user of the telephone selects the cellular mode using the specific key of the input keyboard 1 and, under the control of this selection, the switch 17 switches to the cellular mode position.

In cellular mode, the mobile telephone 20 operates in a conventional manner, like an ordinary mobile telephone. Using the content of the electronic chip of the SIM card, the mobile telephone 20 executes the authentication protocol by the cellular network 101 by supplying the latter with its authentication data, in order to be authenticated by the network. cellular 101. After authentication, the mobile telephone 20 can communicate with a correspondent, through the cellular network 101, using the GSM communication protocol and the radio frequency specific to the GSM network.

Mobile phone operation in private mode

In order to communicate through the PSTN network 100, and when it is in the vicinity of the private base 30, in the coverage area of the latter, the user of the mobile telephone 20 selects the private mode using the specific key on the input keyboard 1.

Under the control of the selection of the private mode, the switch 17 being in the cellular mode position, the mobile telephone 20 sends to the cellular network 101 a warning signal, accompanied here by the telephone call number of the base 30 on the network PSTN 100, previously recorded in memory block 14, to command the cellular network 101 to switch incoming calls addressed to the mobile telephone 20 through the cellular network 101, on the private base 30, that is to say to the telephone number transmitted, via the PSTN 100 network. 8

Under the control of the control block 15, the switch 17 is then switched to the private mode position so as to connect the memory block 14 to the control block 15 and to inhibit the SIM card 13.

Then the mobile telephone 20 and the base 30 pair with one another, by executing the pairing protocol contained, on the base side 30, in the memory block 42, and, on the telephone side, in the memory block 14. During this pairing step, the telephone 20 identifies itself with the base 30 by supplying it with its identity contained in the memory block 14. The base 30 compares this identity with that contained in the memory 42 and, the identity provided by the mobile phone 20 being identical to that stored in the base 30, the latter sends in response to the mobile phone 20 a random number. The mobile telephone 20 and the base 30 both encrypt the random number each by means of the common encryption program and using, as encryption key, the assigned secret identification key. to the mobile telephone 20 by the base 30. After having encrypted the random number supplied by the base 30, the mobile telephone 20 returns it to the base 30 in its encrypted form, and the base 30 compares it with the result which it has even obtained by encryption. In the event of identity, the base 30 validates the access of the mobile telephone 20 to the base 30 and therefore to the PSTN network 100.

The mobile telephone 20, paired with the base 30, functions as a cordless telephone telephone handset, the cordless telephone being understood, it will be recalled here, of the assembly comprising the base 30 and the mobile telephone 20.

During a communication, through the PSTN network 100, between the mobile telephone 20 and a correspondent, via the private base 30, the base 30 receives, by the PSTN network 100, the information originating from the correspondent and retransmits it, by its radio antenna 41, to the mobile telephone 20. The base 30 moreover receives, by its radio antenna 41, information transmitted by the mobile telephone 30 and retransmits it to the correspondent, through the PSTN network 100. During the communication between base 30 and mobile phone 20, base 30 and mobile phone 20 communicate with each other using the CT2 communication protocol. Everything happens as if the mobile telephone 20 were a simple cordless telephone handset paired with the base 30 and communicating with it by radio.

In the event of an incoming call for the mobile telephone 20, on the cellular network 101, the latter, previously warned of the passage of the mobile telephone 20 in private mode, directs the call to the private base 30, through the PSTN network 9

100. Upon receiving the call, the user "picks up" the line by pressing a specific key on the keypad of the mobile phone 20 and communicates with the caller, through the PSTN network 100 and through the base 30, using mobile phone 20 as a cordless telephone handset paired with base 30.

In the event of an outgoing call, the user dials the number on the keypad of the mobile phone 20 and establishes a communication with a correspondent, through the PSTN network 100, via the private base 20, the mobile phone. 20 functioning as a cordless telephone handset paired with the private base 20.

During a communication between the mobile telephone 20, paired with the base 30, and a correspondent, through the PSTN network 100, the base 30 plays a role analogous to that of a base station of a cellular network 101, to which the mobile phone 20 connects, by radio link, to communicate through the cellular network 101. The base 30 acts as a private base station of the PSTN network, to which the mobile phone 20 connects to no longer communicate through its usual network, but through another network, in this case the PSTN 100 network.

It will be emphasized that the mobile telephone 20, in private mode, can be used with or without the SIM card inserted in the telephone 20.

In the event of an outgoing call, instead of pressing a specific key for selecting the operating mode of the mobile telephone, one could consider adding a distinctive element to the telephone number dialed on the mobile telephone keypad. example the element "*" prefixed to the normal telephone number. In this case, the telephone would be able to recognize the element "*" and interpret it as a command to select the private mode.

Of course, the base could contain in memory the authentication data of a plurality of mobile telephones capable of pairing with the base and authorized to access the PSTN network 100 through it. The base could also be paired with ordinary telephone handsets, that is to say unable to communicate through a network other than that of the base.

In the description which has just been made, it has been provided that the telephone and the base 30 communicate with each other using the CT2 protocol of 10 wireless telephony. We could consider that they use another wireless telephone communication protocol, a cell phone communication protocol or any other communication protocol.

In place of memory block 14, containing the authentication data of the mobile telephone by the private base, the base pairing protocol, the communication protocol with the base and the initial identification registration protocol with the internal base of the mobile telephone 20, a memory, of electronic chip for example, could be provided, supported by a card intended to be inserted in a removable manner in the telephone, as is the case for the card 13.

Finally, in the particular example of the above description, the mobile telephone is arranged to communicate through a GSM cellular network 101 and the private base is arranged to communicate through the PSTN network 100. The invention obviously applies to a mobile telephone arranged to communicate through any other cellular network and to a base arranged to communicate with any other telephone network.

Claims

11

1- Mobile telephone of a cellular telephone network comprising means (13, 6-12) for communicating through said cellular network (101), comprising means for pairing with a private base (30) of wireless telephone arranged for communicate via another telephone network (100) and, the mobile telephone (20) being thus arranged to operate either in cellular mode or in private mode as telephone receiver of the cordless telephone, means (1, 17) are provided for selecting one of the two modes, cellular and private, telephone characterized in that the means for communicating through the cellular network comprising means of authentication (13) of the telephone by the cellular network (101) and the means selection (1, 17) are arranged, in case of selection of the private mode, to inhibit the means (13) of authentication of the telephone by the cellular network (101).

2- Telephone according to one of claims 1 to 3, wherein the base pairing means (30) comprises means for authenticating the mobile phone (20) by the base (30).

3- Telephone according to claim 2, comprising means for executing an initial identification registration protocol with the base (30).

4- Telephone according to one of claims 1 to 3, comprising means for, if necessary, notifying the cellular network (101) of the selection of the private mode.

5- Telephone according to one of claims 2 to 4, wherein the authentication means by the cellular network (101) comprises a support card (13) of a memory for storing authentication data.

6- A method of pairing between, on the one hand, a mobile telephone (20), according to claim 1, arranged to communicate through a telephone (101), cellular network, and, on the other hand, a private base ( 30), a wireless telephone arranged to communicate through another telephone network (100), method in which the mobile telephone (20) identifies itself with the base (30) which controls access to the mobile telephone (20 ) to said other telephone network (100), method characterized in that during an initial registration step, the mobile telephone 12 registers his identity with the base and the base assigns to the mobile telephone a secret encryption key.

7- Method according to claim 6, wherein during the pairing of the mobile phone (20) and the base (30), the base (30) transmits to the mobile phone (20) a random number as the mobile phone (20 ) and the base (30) both encrypt, using said secret encryption key, the mobile telephone (20) transmits the random number thus encrypted to the base (30) which compares it to encrypted number which it has itself obtained and, in the event of identity, authorizes access from the mobile telephone (20) to said other telephone network (100).

8- Method according to one of claims 6 and 7, wherein, in the event of an incoming call intended for the mobile telephone (20), on the cellular network (101), the latter switches the call to the private base ( 30) wireless telephone through said other telephone network (100).