PROCEDURE AND SYSTEM FOR SETTING UP A CALL IN A WIRELESS LOCAL LOOP

Abstract: The invention relates to a procedure for setting up a call in a wireless local loop (WLL) based on mobile communication technology, in which subscriber's stations (MS) are connected via a radio link to an access node (AN) and from the access node to a local exchange (LE) in a wired network. To achieve faster call setup, the message-based dialling information consistent with mobile communication specifications sent by a subscriber's station (MS) is converted in the access node (AN) into message-based dialling information consistent with the signalling used in the interface between the local exchange and the access node, and this information is transmitted to the local exchange.

Description: PROCEDURE AND SYSTEM FOR SETTING UP A CALL IN A WIRELESS LOCAL LOOP The present invention relates to a procedure for setting up a call in a wireless local loop based on mobile communication technology, in which subscriber's stations are connected via a radio link to an access node and from the access node to a local exchange in a wired network. In a wireless local loop (WLL), a subscriber's station is connected via a wireless link to an access node or a WLL controller. The access node may consist of multiplexers, crossbar switches and various transmitting systems. The WLL system may be based e.g. on technology used in mobile telephone systems, such as the GSM/DCS1800 technology (GSM, Global System for Mobile Communications; DCS, Digital Cellular System) . GSM is a European digital mobile communication system standardized by ETSI . DCS-1800 is a mobile communication system standardized by ETSI, which is based on the GSM specifi- cation and aims at a more effective use of microcells and which works in the frequency range of 1800 MHz. Between the subscriber's station and the access node there is a base station, through which call signals sent by the subscriber's station over a radio channel are transmitted via the access node to a public telephone network and vice versa. The WLL controller can be connected to the telephone exchange using e.g. the V5.2 or V5.2 protocol . Open interfaces (V5.1 and V5.2) between an ac- cess node and a telephone exchange are defined in the ETSI (European Telecommunications and Standards Institute) standards of the ETS 300 324 and ETS 300 347 series. V5 interfaces enable subscribers belonging to a physically separate access network, which may be either a wi- red or a wireless network, to be connected to a telephone exchange using a standard interface. A dynamic concentrator interface V5.2 consistent with the standards ETS 300 347-1 and 347-2 consists of one or more (1 - 16) PCM (Pulse Code Modulation) cables. One PCM cable comprises 32 channels, each of which with a transfer rate of 64 kbit/s, i.e. 2048 kbit/s in all. The V5.2 interfa- ce supports analogue telephones as used in the public telephone network, digital, such as ISDN (Integrated Services Digital Network) basic and system subscriber connections as well as other analogue or digital terminal equipment based on semi-fixed connections. In a prior-art method, when the dialling information is to be transmitted from an access node based on a mobile communication system to a local exchange in a wired network, the message-based dialling information consistent with mobile communication specifications has to be converted in the access node into a voice- frequency multifrequency code (MFT, multifrequency tone or DTMF, dual tone multifrequency) acceptable to the local exchange. The problem is that generating such signal tones is slow because the signal tones and the intervals between them should have a certain duration according to recommendations of the CCITT (CCITT, International Telegraph and Telephone Consultative Committee, working under ITU; ITU, International Telecommunication Union, working under the UN) , which retards call setup. The object of the invention is to eliminate the drawback mentioned above. A specific object of the invention is to present a procedure that allows faster setup of a call from an access node to a local exchange in a wired network. The procedure of the invention is characterized by what is presented in claim 1. According to the invention, to achieve faster call setup, the message-based dialling information consistent with mobile communication specifications is con- verted in the access node into message-based dialling information consistent with the signalling used in the interface between the local exchange and the access no- de, and this information is transmitted to the local exchange . The invention has the advantage that it enables faster call setup from an access node to a local exchan- ge in a wired network. In an embodiment of the procedure, the subscriber's station is connected to the access node via a GSM/DCS interface, in which case the dialling information given by the subscriber's station is in accordance with the GSM specification. The signalling from the subscriber's station to the network is therefore implemented using signalling consistent with the GSM standard. In an embodiment of the procedure, the subscri- ber ' s station is connected from the access node to the wired network local exchange via a V5 interface consistent with the ETS 300 347-1 standard, and the message- based dialling information consistent with mobile communication specifications is converted in the access node into message-based dialling information consistent with the ETS 300 324-1 specification. In an embodiment of the procedure, the message- based dialling information consistent with the ETS 300 324-1 specification is transmitted in the form of so-called SIGNAL messages via the signalling channel of the V5 interface to the local exchange . In the following, the invention is described in detail by the aid of a few examples of its embodiments by referring to the attached drawing, which is a diagram representing an example of a system applying the procedure of the invention. The figure presents a wireless local loop WLL comprising a number of subscriber's stations MS, which communicate with an access node AN over a radio link. The signalling between the subscriber's station MS and the access node AN is message-based signalling consistent with the GSM specifications (GSM/DCS1800) . The ac- cess node AN again is connected to a local exchange LE in a wired network via a V5.2 interface consistent with the ETS 300 347-1 standard. When a call is made from the subscriber's station MS, the message-based dialling in- formation consistent with the GSM specification is converted into message-based dialling information consistent with the ETS 300 324-1 standard, and this information is transmitted in the V5 interface as message-based signalling in the form of so-called SIGNAL messages via the signalling channel of the V5 interface to the wired network local exchange LE . The use of SIGNAL messages means that the PSTN protocol (one of the five network layer protocols of the V5.2 interface) is used. Therefore, WLL subscribers are interpreted in the local exchan- ge as being normal analogue subscribers. If desirable, WLL subscribers can also be regarded in the local exchange LE as ISDN 2B+D subscribers. In this case, the message-based dialling information can be transmitted to the wired network local exchange LE via the signalling channel reserved for the subscriber in the V5 interface in the form of ISDN signalling messages (LAPD signalling) . The invention is not restricted to the examples of its embodiments described above, but instead many va- riations are possible within the framework of the inventive idea defined by the claims.

Claims: CLAIMS 1. Procedure for setting up a call in a wireless local loop (WLL) based on mobile communication technology, in which subscriber's stations (MS) are con- nected via a radio link to an access node (AN) and from the access node to a local exchange (LE) in a wired network, c h a r a c t e r i z e d in that, to achieve faster call setup, the message-based dialling information consistent with mobile communication specifications sent by a subscriber's station (MS) is converted in the access node (AN) into message-based dialling information consistent with the signalling used in the interface between the local exchange and the access node, and this information is transmitted to the local exchange. 2. Procedure as defined in claim 2, c h a r a c t e r i z e d in that the subscriber's station (MS) is connected to the access node (AN) via a GSM/DCS interface and the dialling information given by the subscriber's station is consistent with the GSM spe- cification. 3. Procedure as defined in claim 1 or 2, c h a r a c t e r i z e d in that the subscriber's station (MS) is connected from the access node (AN) to the wired network local exchange (LE) via a V5 interface consistent with the ETS 300 347 standard, and that the message-based dialling information consistent with mobile communication specifications is converted in the access node (AN) into message-based dialling information consistent with the ETS 300 324-1 specification. 4. Procedure as defined in any one of claims 1 - 3, c h a r a c t e r i z e d in that the message-based dialling information consistent with the ETS 300 324-1 specification is transmitted via the signalling channel of the V5 interface to the local exchange (LE) .

Inventors: LALLUKKA TOIVO, LIINAMAA OLLI, PENTTINEN SIMO, RAUTIAINEN JAAKKO, LALLUKKA, TOIVO, LIINAMAA, OLLI, PENTTINEN, SIMO, RAUTIAINEN, JAAKKO
Applicants: LALLUKKA TOIVO, LIINAMAA OLLI, NOKIA TELECOMMUNICATIONS OY, PENTTINEN SIMO, RAUTIAINEN JAAKKO, LALLUKKA, TOIVO, LIINAMAA, OLLI, PENTTINEN, SIMO, RAUTIAINEN, JAAKKO
Application year: 1998
Main classification: H04Q7
IPC codes: H04W84