Abstract:
The aim of the invention is to connect terminals to a communication system in a wireless manner by means of a data packet network. At least one transition device to which a short-range radio module is coupled, and a server for controlling connections to the terminals, are coupled to said data packet network. The transition device is provided with a coupling table comprising addresses of terminals which are situated within the radio coverage of the short-range radio module. The server comprises an allocation table in which a network address of the transition device which enables the terminal to be wirelessly reached is respectively allocated to an address of a terminal. According to the invention, a packet-based alignment protocol is provided in order to dynamically align the allocation table with the coupling table.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation of International Application No. PCT/DE02/02836, filed Aug. 1, 2002 and claims the benefit thereof. The International Application claims the benefits of German application No. 10142007.2 filed Aug. 28, 2001, both of the applications are incorporated by reference herein in their entirety. 

   FIELD OF INVENTION 
   The invention relates to an arrangement for the wireless connection of terminals to a communication system. 
   BACKGROUND OF THE INVENTION 
   With present communication systems, terminals that can serve a variety of purposes, such as the transmission of a voice, video, multimedia, fax, file, program and/or measuring data are increasingly coupled wirelessly. In the meanwhile, a variety of different radio network technologies such as GSM (Global System for Mobile Communication), DECT (Digital Enhanced Cordless Telephony), and particularly Bluetooth, have been developed from this for different fields of application. These radio network technologies differ particularly by the coverage of a particular radio link. The Bluetooth technology, which was standardized by IEEE by IEEE 802.15, in this case is used mainly for short-range wireless communication between different equipment or equipment components, such as between a telephone and headset. The range of a Bluetooth radio link is correspondingly short and extends from approximately 10 cm up to several meters. 
   Modern communication systems frequently provide a number of communication and data services in addition to a wealth of associated performance features. Up until now, however, the utilization of such a variety of communication and data services using a corresponding variety of wirelessly coupled terminals is possible to only a limited extent. Generally, a specific implementation is required for a specific communication or data application. 
   SUMMARY OF THE INVENTION 
   The object of this invention is to provide an arrangement for the wireless connection of terminals to a communication system by means of which a generic platform for the use of different communication and/or data services can be realized by wirelessly coupled terminals. 
   This object is achieved by an arrangement with the features of Claim  1 . 
   The arrangement in accordance with the invention for the wireless connection of terminals to a communication system has a data packet network, such as a local area network (LAN) or a wide area network (WAN), to which at least one transition device with at least one coupled short-range radio module, and a server for controlling the connections to the terminals are coupled. The terminal device in this case can be terminal equipment, personal computers or application programs or client applications running on them, for voice, video, multimedia and/or data communication. The server can be realized in the data packet network, for example as a central unit or as a distributed application and/or integrated into a transition device. 
   The transition device has a coupling table with terminal device addresses of terminal devices in the radio range of at least one short-range radio module. Terminal device addresses in this connection can, for example, be telephone numbers, Internet protocol addresses, e-mail addresses or other URIs (Universal Resource Locators) of terminal devices. 
   The server has an allocation table in which a network address, valid in the data packet network, of the particular transition device is allocated in each case to one or more terminal device addresses, to which a short-range radio module, within whose radio range the terminal device identified by this terminal device address is located, is coupled. To dynamically align the allocation table with the coupling table, i.e. to make the content consistent with the coupling table, a packet-based alignment protocol is provided in accordance with the invention. 
   The coupling of the server and at least one transition device to the data packet network enables the flexibility and large application spectrum of packet-oriented communication networks to be advantageously utilized directly and generically for wireless applications. Because a corresponding packet-oriented communication infrastructure, e.g. in the form of local area networks (LAN) or wide area networks (WAN) is already present in, or being provided in, many places, the invention can generally be implemented at little cost. In particular, a number of the performance features, services and/or applications available in data packet networks of this kind can be used in a relatively simple manner. The arrangement in accordance with the invention thus provides a flexible, expandable, very scaleable, generic platform for using different communication and/or data services by means of wirelessly coupled terminal devices. 
   Using the allocation table, the server can appropriately forward incoming connection requirements for mobile terminal devices via the data packet network to the relevant transition device, the short-range radio module of which enables a relevant terminal device to be instantly, wirelessly reached. The packet-based alignment protocol enables roaming and/or handover of terminal devices to be controlled in a generic manner via the data packet network. 
   Advantageous embodiments and developments of the invention are given in the dependent claims. 
   In accordance with an advantageous embodiment of the invention, the data packet network can be realized by a network based on an Internet protocol. The advantage of this is that because of the worldwide spread of the Internet protocol an enormous variety of performance features, services and/or applications based on this protocol can be directly used. 
   The transition device can have a translator for translating between a network protocol used in the data packet network and the protocol specific to the radio module. In particular, the translator can translate between a connection setup protocol used in the data packet network and a connection setup protocol specific to the radio module. 
   Furthermore, the translator can have a detection device in order to detect, by means of the network protocol used, which application specific to the terminal device a connection to a terminal device is allocated to, so as to enable an application-specific translation to be accordingly performed. 
   Advantageously, the protocol specific to the radio module can have a specific voice interface and a specific data interface. The translator can therefore, for example, translate a Voice-over-Internet-Protocol (VoIP) used in the data packet network to the specific voice interface, and a data protocol, such as WAP (Wireless Access Protocol), HTTP (Hyper Test Transfer Protocol) or SMTP (Simple Mail Transfer Protocol) to the specific data interface. 
   Advantageously, a Bluetooth module can be used as the short-range radio module. Bluetooth modules of this kind have a small installation size, high data transmission rates, good cryptographic properties and high flexibility. 
   In accordance with an advantageous development of the invention, a locating device can be provided for determining the momentary location of a particular terminal device. The location can be determined by means of the allocation table, i.e. the transition device whose short-range radio module is located in the vicinity of the relevant terminal device can be determined by using the network address, stored within it, allocated to the terminal device address of the relevant network address. The location can be determined with greater accuracy the shorter the radio range of the relevant short-range radio module. In the case of a Bluetooth radio module the accuracy of location is within 10 cm to 10 meters. 
   In accordance with a further advantageous development of the invention, a gateway device coupled to the data packet network can be provided for coupling the data packet network to a forwarding communication network. The forwarding communication network can, for example, be a local area network (LAN), a wide area network (WAN), and ISDN (Integrated Services Digital Network) or a GSM (Global System for Mobile Communication) network. 
   In accordance with further advantageous embodiments of the invention, a wirelessly coupled headset for voice connection and/or a wirelessly coupled PDA (Personal Digital Assistant) for data connections can be provided as terminal devices. A PDA of this kind can also be used for voice connections, if a headset is connected to it. In particular, a PDA can be used as a terminal device for entering destination addresses, such as telephone numbers, Internet protocol addresses, mail addresses or other URIs for outgoing connections and for initiating these connections. Thus, for example, a voice connection can be initiated by a subscriber by entering the telephone number at a wirelessly coupled PDA, whereby the voice connection between an external terminal device identified by the telephone number entered and a headset of the subscriber, also wirelessly connected, is set up. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     An exemplary embodiment of the invention is described in more detail in the following with the aid of a drawing. 
     The drawing is a schematic representation of a communication system with wirelessly coupled terminal devices. 
   

   DETAILED DESCRIPTION OF INVENTION 
   The drawing is a schematic illustration of a communication system with wirelessly coupled terminal devices that, in the exemplary embodiment shown, are arranged as headsets HS 1 , HS 2 , HS 3  and PDA. The PDA in the illustration is given the same reference designation. The communication system includes a data packet network LAN, e.g. an Ethernet designed as a local network, the data transmission of which is preferably based on protocols of the TCP/IP family of protocols. Connected to the data packet network LAN is a server S, e.g. a gatekeeper in accordance with ITU-T recommendation H.323, that controls the connections carried in the data packet network LAN, e.g. for voice, video, multimedia and/or data communication and in particular a setup of such connections. This control preferably takes place by means of client-server structures based on Internet protocols. Connections to voice, video and/or multimedia communication via local networks based on Internet protocols are frequently designated VoIP (Voice/Video over Internet protocol) connections. 
   Gateways GW 1  and GW 2  are also coupled to the data packet network LAN as transition devices. In this case, an Internet protocol address IP 1  is allocated to gateway GW 1  and an Internet protocol IP 2  to gateway GW 2 , in each case as a network address. The Internet protocol addresses IP 1  and IP 2 , designated in the following as IP addresses, are valid at least within the network, i.e. within the data packet network LAN, and provide a unique identification of the particular allocated gateway GW 1  or GW 2  within the data packet network LAN. 
   Bluetooth transceiver modules BT 1  and BT 2 , referred to in the following as Bluetooth modules, are coupled to gateways GW 1  and GW 2  as short-range radio modules. Bluetooth module BT 1  is coupled to gateway GW 1  and Bluetooth module BT 2  to gateway GW 2 . Bluetooth modules BT 1  and BT 2  are preferably integrated into the relevant gateway GW 1  or GW 2 . An exchange of control and useful data between a particular gateway GW 1  or GW 2  and the Bluetooth module BT 1  or BT 2  coupled to it takes place by means of a Bluetooth protocol specific to a radio module, with a specific voice interface VOICE and a specific data interface DATA. 
   In accordance with an alternative form, instead of one or more Bluetooth modules, other radio modules, e.g. in accordance with the DECT (Digital Enhanced Cordless Telephony) or GSM (Global System For Mobile Communications) standard are used, with specific voice, data, video and/or multimedia interfaces as appropriate. 
   For this exemplary embodiment let us assume that the headsets HS 1  and HS 2  and the PDA are momentarily in the radio range of the Bluetooth module BT 1  and headset HS 3  is momentarily in the radio range of Bluetooth module BT 2 . Headsets HS 1 , HS 2  and HS 3  and the PDA each have their own Bluetooth module (not illustrated) for wireless coupling to the particular opposite module BT 1  or BT 2 . In addition to headsets HS 1 , HS 2  and HS 3  and the PDA, any other terminal devices such as a personal computer or an application program running on a PDA or client applications can also be wirelessly coupled. 
   A telephone number RN 1  is allocated to headset HS 1  and telephone number RN 2  to headset HS 2 , a telephone number RN 3  to headset HS 3  and an e-mail address MA to the PDA. Telephone numbers RN 1 , RN 2  and RN 3  and the e-mail address MA are each network-overlapping valid terminal addresses, that in each case provide a network-overlapping, unique identification of an allocated terminal. 
   Furthermore, a personal computer PC, a gateway EXTGW coupled to a forwarding communication network WAN or ISDN and a gateway GSMGW leading to a GSM radio network are connected to the data packet network LAN. The terminal devices HS 1  HS 2 , HS 3  and PDA can be connected to public networks via gateways EXTGW and GSMGW. Gateways EXTGW and GSMGW are preferably formed as VoIP gateways in accordance with ITU-T recommendation H.323 and perform the relevant protocol translations. The forwarding communication network can, for example, be a wide area network WAN, e.g. the Internet, an ISDN network ISDN or other local network. 
   An IP address (not illustrated), that is at least valid internally within the network, by means of which these devices within the data packet network LAN can be identified, is allocated to the personal computer PC and gateways EXTGW and GSMGW in each case. In particular, the server S can be coupled to gateways GW 1 , GW 2 , EXTGW and GSMGW and to the personal computer PC by means of the Internet protocol. The server S in this case, as in this exemplary embodiment, can be realized as a central network device or, alternatively, realized in a gateway or a server application distributed in the data packet network LAN. 
   Gateway GW 1  has a translator IWU, to which the Bluetooth module BT 1  is coupled through the specific data interface DATA and the specific voice interface VOICE. The translator IWU performs a protocol translation between the Internet protocol used in the data packet network LAN and the Bluetooth protocol specific to the radio network. In particular, in this case a translation is made between a connection setup protocol VAP, e.g. in accordance with ITU-T recommendation H.323 and a Bluetooth connection setup protocol. In doing so, the translator IWU uses the network protocol used in the data packet network LAN or connection setup protocol VAP to determine which application, e.g. voice or data application, a particular connection is allocated to, and performs an application-specific protocol accordingly. In this exemplary embodiment, translation takes place to the voice interface VOICE or data interface DATA, depending on whether it is a voice or data application. 
   Gateway GW 1  also has a coupling table KTAB in which the telephone numbers RN 1 , RN 2  and e-mail address MA of the terminal devices momentarily present in the radio range of the Bluetooth module BT 1 , in this case HS 1 , HS 2  and PDA, are stored. The coupling table KTAB is dynamically administered by the gateway GW 1 . As part of this, the terminal device addresses of the terminal devices that newly arrive in the radio range of the Bluetooth module BT 1 , or check in with it, are entered in the coupling table KTAB. Terminal device addresses are removed from the coupling table KTAB correspondingly if the relevant terminal devices leave the radio cell of the Bluetooth module BT 1  or log off from it. 
   As for gateway BW 1 , gateway GW 2  also has a corresponding translator and corresponding coupling table. For reasons of clarity, these functional components are not shown in the illustration for gateway GW 2 . 
   Furthermore, the server S contains an allocation table ZTAB in which the IP address IP 1  or IP 2  of those gateways GW 1  or GW 2  through which a terminal device identified by the particular terminal device address can be reached at that moment is allocated to the terminal devices addresses RN 1 , RN 2 , RN 3  and MA. In this exemplary embodiment, IP address IP 1  of gateway GW 1  is allocated to terminal device addresses RN 1 , RN 2  and MA and IP address IP 2  of gateway GW 2  is allocated to telephone number RN 3 , in the allocation table ZTAB. 
   The allocation table ZTAB is dynamically administered by server S, where it is continuously aligned with the coupling table KTAB so that the data content of both tables is consistent with each other. 
   The allocation table ZTAB is aligned with the coupling table KTAB by means of an alignment protocol AP based on an Internet protocol, that is performed via the data packet network LAN between the server S and gateway GW 1 . By means of the alignment protocol AP, a current data content of the coupling table KTAB is transmitted in each case via the data packet network LAN to the server S, to dynamically update the allocation table ZTAB. The alignment protocol AP is in this case preferably based on a client-server principle. In this example, the terminal device addresses RN 1 , RN 2  and MA stored in the coupling table KTAB, together with IP address IP 1  of gateway device GW 1 , are transmitted to the server S as part of the alignment protocol, and there they are allocated to each other and stored in the allocation table ZTAB. Immediately a further terminal device (not illustrated) is checked in with the Bluetooth module BT 1 , its terminal device address is stored in the coupling table KTAB and transmitted to the server S by means of the alignment protocol AP, where this terminal device address is allocated to the IP address IP 1  of gateway GW 1  and stored in the allocation table ZTAB. By means of the allocation table ZTAB, the server S can control roaming and/or handover of mobile terminal devices. The allocation table ZTAB thus acts as a roaming or handover table and is administered by the packet-based alignment protocol AP in a generic manner and not, as with prior art, in a manner specific to radio networks. 
   A corresponding alignment protocol (not shown for reasons of clarity) also runs between the server S and all other terminal devices, in this case G 2 , PC, EXTGW and GSMGW, for the data packet network LAN. 
   For this exemplary embodiment let us assume that as an operationally-typical situation a user is wearing the headset HS 1  and also the PDA. Incoming calls through the headset HS 1  are received by the user without a further aid. For outgoing calls, the user can use the PDA by entering a destination number to it and initiating the call. As part of the call, a connection is then set up between the called terminal and the headset HS 1 . Generally, wireless voice connections can be realized by means of the headset HS 1  via the specific voice interface VOICE, and by means of the PDA wireless data connections, e.g. for the transmission of e-mails can be realized via the specific data interface DATA. If the PDA has its own connection for headsets, voice connections can also be set up via the PDA. 
   In this exemplary embodiment, the headset HS 1  and the PDA are momentarily in the radio range of Bluetooth module BT 1  and are checked in with it. Consequently, the telephone number RN 1  of the headset HS 1  and the e-mail address MA of the PDA are stored in the coupling table KPAB of gateway GW 1 . 
   In the following let us assume that a call for telephone number RN 1  arrives from the forwarding communication network WAN or ISDN. The arrival of the call is transmitted by the gateway EXTGW, by means of an Internet protocol-based connection setup protocol VAP used in the data packet network LAN, e.g. in accordance with the ITU-T recommendation H.323, to the server S. The connection setup protocol VAP is preferable based on a client-server model. As part of the connection setup protocol VAP, the telephone number RN 1  of the called terminal device HS 1  is transmitted to the server S. 
   Using the connection setup protocol VAP, the server S first determines the application to which the connection to be set up is allocated. In this exemplary embodiment let us assume that this is a telephone application. The server S then searches the allocation table ZTAB for the received telephone number RN 1 , to determine whether the terminal device identified by it can be reached through the data packet network LAN controlled by server S, in order to determine the appropriate gateway. In this exemplary embodiment, the server determines that the telephone number RN 1  is allocated to IP address IP 1  of gateway GW 1  and then, with the aid of the connection setup protocol VAP, switches the incoming call and telephone number RN 1  through to gateway GW 1  identified by IP address IP 1 . The connection setup and the necessary address resolution are thus performed by the server S using the allocation table ZTAB. If the terminal device HF 1  enters the radio cell of a different Bluetooth module, e.g. BT 2 , the allocation table ZTAB is automatically updated with the aid of the alignment protocol AP, so that succeeding incoming connection requests, or already existing connections, are diverted to the relevant gateway, in this case GW 2  (roaming or handover). 
   The call switched to gateway GW 1  is allocated by gateway GW 1  to headset HS 1  by means of the received telephone number RN 1  and put through to headset HS 1  through the Bluetooth module BT 1 . 
   By means of the coupling of Bluetooth and Voice-over-IP-technologies in accordance with the invention, the various performance features and powerful infrastructure of Voice-Over-Internet Protocol networks, already widespread, can be used for the wireless connection of terminal devices of various kinds by means of Bluetooth modules.