Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W76/00—Connection management
  • H04W76/10—Connection setup
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W84/00—Network topologies
  • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
  • H04W84/10—Small scale networks; Flat hierarchical networks
  • H04W84/14—WLL [Wireless Local Loop]; RLL [Radio Local Loop]

Definitions

• the invention relates to a method and an arrangement for establishing an incoming connection in a data transfer system and a terminal.
• the invention is used particularly for specifying which service is to be used in an incoming data connection.
• the invention is applied preferably in Wireless Local Loops WLL.
• Present-day mobile station systems supply the subscribers with various data transfer properties in addition to the conventional speech service. These can be asynchronous network services (Bearer services) or Facsimile Group 3 teleservices.
• Generally data services make use of certain specified communications protocol inside the mobile station network.
• GSM Global System for Mobile Communications
• GSM Global System for Mobile Communications
• RLP radio link protocol
• GSM facsimile protocol A digital connection from the mobile station network to a fixed network, such as ISDN (Integrated Services Digital Network) network or Public Switched Telephone Network PSTN, can use different kinds of protocols.
• the mobile station system utilizes adapter procedures for adapting the internal data connection of the mobile station network to the protocols used by terminals and other communications networks.
• the adapter procedures are a terminal adapter (TAF, Terminal Adaptation Function) in the interface between the mobile station and data equipment connected to it and a network adapter (IWF, Interworking Function) in the interface between the mobile station network and communications network, usually linked to the mobile station switching center.
• TAF Terminal Adaptation Function
• IWF Interworking Function
• Fig. 1 shows the basic structure of the GSM system which consists of two parts: the base station system BSS and the network subsystem NSS.
• the base station system BSS and the mobile stations MS communicate via radio signals.
• each cell is served by the base station BTS.
• a group of base stations are connected to the base station controller BSC whose function is to control the radio frequencies and channels which are used by the base station BTS.
• the base station controllers are connected to the mobile station switching center MSC.
• Certain mobile station switching centers are connected to other data transfer networks, such as the Public Switched Telephone Network PSTN, and they contain gateway procedures for the connections for transmitting to these networks and for receiving from them. These mobile station switching centers are known as gateway mobile switching centers GMSC.
• Subscriber data is stored in the Home Location Register HLR from which they are partly copied to the Visitor Location Register VLR of the mobile station switching center in that area in which the present mobile station is situated.
• the above mentioned databases HLR and VLR also contain information of data services included in the subscriber extension.
• the GSM system has been described more closely, for example, in the GSM system standaids which have been published by European Telecommunication Standards Institute (ETSI) and in the publication Mouly, Pautet, The GSM System for Mobile Communications, 1992.
• the network services of the GSM system have been described in more detail in the ETSI specification GSM 02.02 version 5.0.1 and the teleservices in the specification GSM 02.03 version 5.0.1.
• signalling usually supports the transfer of data service specific parameters. Often the signalling does not, however, support the transfer of these parameters in all networks through which the connection is routed. This is the case, for example, when the call comes from the Public Switched Telephone Network PSTN or it has been routed through it. Thus no data is transmitted to the mobile station system with respect to which data service or adapter equipment the incoming connection requires.
• a prior known solution to the above mentioned problem is a Multi Numbering Scheme wherein the mobile station subscriber has service related subscriber numbers, i.e. the international ISDN numbers of the mobile station subscriber MSISDN (Mobile Subscriber ISDN number).
• the subscriber has as many subscriber numbers as there are different services to which one can receive incoming connections.
• the calling subscriber selects from the mobile station subscriber numbers the one corresponding to the desired service.
• the subscriber services are specified in the subscriber's Home Location Register HLR which also stores other subscriber data in a permanent form.
• the Home Location Register also data concerning the logical connection between the subscriber's subscriber numbers and services is stored.
• the Home Location Register includes a so-called BCIE element which is appended to the subscriber number describing the type of connection and the network services and protocol needed for the connection.
• the IWF can be configurated according to this data.
• the subscriber has a separate subscriber number for each service to be used.
• the subscriber can have, for example, a Speech service, an Asynchronous 3.1 kHz bearer service (a modem), an Asynchronous UDI bearer service and a Facsimile Group 3 teleservice, and in such a case the subscriber would need four separate subscriber numbers. This large amount of subscriber numbers causes problems both to the subscriber and to the network operator.
• WLL Wireless Local Loops
• Fig. 2 shows a configuration of the WLL system according to the prior art wherein the GSM system network is used as such.
• the terminal equipment comprises a fixed WLL temiinal device 22 and a subscriber device, such as a wired telephone 21, which has been connected to the WLL terminal 22.
• Fig. 3 shows another WLL system configuration according to the prior art.
• the GSM network base station controller BSC, mobile station switching center MSC, Home Location Register HLR and Visitor Location Register VLR have been substituted by a WLL system specific network element, a WLL-ACCESS node.
• the WLL- ACCESS node may comprise, for example, the following procedures: transcoding, echo suppression, basic functions of location registers (HLR, VLR) and adapter functions IWF for data services.
• IWF adapter equipment is required if data or facsimile functions are supported in the system.
• the subscriber In order to be able to receive connections demanding different protocols, the subscriber has to subscribe to many services and be supplied with subscriber numbers for each service from the network operator. In addition, the subscriber has to obtain a separate terminal for each service if the terminal cannot cope with several subscriber numbers. Moreover, the system users have to cope with and handle a large amount of subscriber numbers since, as the connection is being established to a desired subscriber extension, one has to know which subscriber number is associated with the particular service being used.
• Multi Numbering Scheme can then only to a limited extent or even not at all separate applications from each other which function in different subscriber devices.
• the aim of the present invention is to avoid the above described disadvantages of the prior art.
• One idea of the invention is that a traffic channel for the incoming connection is formed from which some signal is received and from the signal, signalling data, synchronization data or other data is monitored and on the basis of this data, the data service to be used is specified.
• the incoming data connection can be established so that for data services, there is no need for several subscriber numbers, several subscriber extensions or several terminals.
• a significant advantage of the invention is that all data/fax connections need not be routed via a service specific network adapter, but data transfer can be directed through the data transfer network in a generic form since the terminal recognizes the type of connection. This advantage is attained particularly in data/fax connection between two terminals of the same WLL network. Thus only few service specific network adapters are needed in the data transfer system, a great part of the network adapters being non-service specific.
• the subscriber When the solution according to the invention is used, the subscriber needs just one subscriber number for data services he/she uses. This decreases problems encountered by the subscriber, the network users and the network operator due to the large amount of subscriber numbers.
• connection is received to the subscriber's subscriber number which is common to at least two data services, - the traffic channel of the received connection is monitored,
• the data service used by the calling party is recognized on the basis of some characteristic data, such as signalling or synchronization,
• the terminal is configurated according to the recognized data service for the incoming connection.
• fig. 1 shows a block diagram of a GSM mobile station system according to the prior art
• fig. 2 shows a block diagram of a WLL system based on the GSM system according to the prior art
• fig. 3 shows a block diagram of another WLL system which is based on a GSM radio interface
• fig. 4 shows protocols and procedures which are needed in GSM system transparent network services
• fig. 5 shows protocols and procedures which are needed in GSM system non- transparent network services
• fig. 6 shows protocols and procedures which are needed in a GSM system transparent Facsimile Group 3 network service
• figs 7A and 7B show a method according to the invention for the establishment of an incoming data transfer connection
• fig. 8 shows baseband and RE parts of a terminal according to the invention and the connection of the terminal to the data transfer system
• fig. 9 shows a WLL terminal according to the invention wherein there is a common line adapter for analogue connections and
• fig. 10 shows another WLL terminal according to the invention wherein there are separate line adapters for analogue connections.
• Figs. 1-3 were already described above in the context of the description of the prior art.
• the invention is described by detailing first the protocols which are used in data services of a data transfer system based on the GSM system according to the invention. Thereafter, a method according to the invention is described for establishing an incoming data transfer connection by means of Fig. 7. Finally, baseband and RF frequency parts of a terminal according to the invention are described by means of Fig. 8 as well as some WLL terminals according to the invention by means of Figs. 9 and 10.
• Figs. 4, 5 and 6 show examples of protocols and procedures which are needed in data transfer between a mobile station and a network adapter.
• Fig. 4 shows protocols used in asynchronous transparent network service
• Fig. 5 shows protocols used in asynchronous non-transparent service
• Fig. 6 shows protocols used in transparent GSM facsimile service.
• a non-transparent circuit-switched connection between a terminal adapter TAF and a network adapter IWF on a GSM traffic channel comprises several protocol layers which are common to all of these services. These include a variety of rate adaptation procedures RA (Rate Adaptation), such as RAT between the terminal adapter TAF and a CCU unit located in the base station system BSS; RA1 between the CCU unit and a transcoder unit TRAU located separately from the base station and RA2 between the transcoder unit TRAU and the network adapter IWF.
• the rate adaptation procedures RA have been specified in the GSM recommendations 04.21 and 08.20.
• the RAT rate adapted information has additionally been channel coded in the way specified by the GSM recommendation 5.03, which is illustrated by blocks FEC in the mobile station MS and the CCU unit.
• the network adapter IWF and the terminal adapter TAF there are additionally higher level protocols which are service specific.
• an asynchronous-synchronous conversion RAO is needed and a modem or an ISDN rate adapter.
• L2R Layer 2 Relay
• RLP Radio Link
• the L2R procedures for non-transparent character format protocols have been specified, for example, in the GSM recommendation 07.02.
• the RLP protocol has been specified in the GSM recommendation 04.22.
• the RLP is a frame structured, balanced (HLDC type) data transfer protocol wherein error correction is based on retransmission of distorted frames at the request of the receiving party.
• the terminal interface is, for example, according to CCITT V.24 and it has been marked by symbol L2 in Fig. 5.
• the terminal adapter and the network adapter need the GSM facsimile protocol procedures.
• the GSM facsimile service has been specified in the GSM recommendation 03.45.
• Figs. 7A and 7B show a method according to the invention for establishing an incoming connection to the terminal 700.
• the terminal recognizes first the called subscriber number in phase 702 after which it is checked whether the called subscriber number is connected to the data service, phase 704. This can be defined also on the basis of some other identifier received from the data transfer system if the same subscriber number is used for speech and data connection.
• the connection is established to a telephone device attached to the terminal or to acoustic devices integrated into the terminal, phase 706.
• the traffic channel is monitored for recognizing the service data attached to the data connection, phase 710. If V.110 synchronization frame is recognized from the signal of the traffic channel in phase 712, transparent traffic channel synchronization is performed, phase 714. If after this, a synchronization frame according to the Facsimile Group 3 is recognized in phase 716, a transparent establishment of connection according to the Facsimile Group 3 is performed, phase 718. If in phase 716 some other identifier is recognized which is connected to data services according to the subsciber devices of the terminal, the connection is established to the subscriber device corresponding to the service in question, phase 722.
• phase 712 If in phase 712 an RLP frame is recognized, phase 730, formation of a link according to the RLP protocol is performed, phase 732. Thereafter, from the traffic channel an L2R PDU identifier is received and on the basis of its contents it is determined whether the connection is synchronous or asynchronous, phase 734. Based on this, either an asynchronous connection, phase 740, or a synchronous connection, phase 742, is established. Other phases of the establishment of the connection can subsequently be attached to the establishment of connection according to the protocol and application used.
• Fig. 8 shows a simplified block diagram of a mobile station 800 according to the invention and its attachment to the cellular system.
• the mobile station comprises an antenna 801 for receiving a radio frequency signal, i.e. an RF signal transmitted by the base station.
• the received RF signal is fed through duplex filter 802 to an RF receiver 811 in which the signal is amplified and converted into a digital form. Thereafter, the signal is detected and demodulated, block 812, and decoding is performed in block 813.
• connection processing is performed to the received signal wherein the signal is also converted into an audio signal, block 830. Thereafter the signal is directed to an earpiece connected to the mobile station/terminal (not shown in Fig. 8).
• the signal received from the traffic channel is monitored in the control unit according to the invention for detecting the identifier connected to the data service.
• the functions of the signal processing block are ensured to be compatible with the data service used and the input and output connections are connected to a subscriber device corresponding to the selected data service/application, for example, by means of a connection control signal formed in the control unit.
• the decoded data can be transferred to an external data processing device via an interface in the mobile station.
• the data to be received can be processed in the terminal, for example, by storing data in a memory 804 and showing it on a display 832.
• a processing block for a speech signal 833 which converts the audio signal received from a microphone into a digital signal.
• the information to be transmitted is data, it can be read from the memory 804 or received from an external data processing device via an external interface.
• the data to be transmitted is coded in block 821 according to selected connection parameters. From the coded data, bursts are formed, block 822, which are modulated into an RF signal to be transmitted in block 823.
• the RF signal to be transmitted is transferred to the antenna 801, for example, through a duplex filter 802. Also the above mentioned data processing and transmitting functions are controlled by the control unit 803.
• the blocks of the mobile station according to the invention can be formed by means of components known per se.
• a control unit controlling the other blocks performs the control operations of the blocks according to dedicated software and thus the above described functions of the blocks according to the invention are achieved.
• Fig. 8 shows additionally the parts of the cellulai- system which are used in the establishment of connection and data transfer and which were already dealt with more closely above.
• the RF signal is transmitted and received through an antenna 850 of a base station 851.
• Data transfer connection is established from the base station 851 further to a switching center 853 through a base station controller 852.
• the switching center 853 is additionally linked to other base stations of the system and, for example, to the public switched telephone network PSTN.
• Fig. 9 shows a WLL terminal according to the invention.
• a facsimile device 902 and a work station 903 have been implemented in such a way that to a line adapter (LA) 919 of a connection part 910, two separate ports are connected, CONNECTION 1 and CONNECTION 2.
• the line adapter is connected to one of the two connections by means of controllable switches 916 and 917.
• the switches are controlled by the control unit of a baseband part (BB) 912 of the WLL terminal which receives the subscriber device data from the data transfer system.
• BB baseband part
• CONNECTION 3 in the baseband part, for example, for the asynchronous connection of a work station NT (Network Terminal).
• Data transmission between the work station and the WLL terminal can be implemented preferably via an RS232 serial interface.
• the line adapter does not contain its own processor but the control unit 912 of the baseband part also controls the functions of the line adapter. If the line adapter has a processor of its own, also it can control the switches 916 and 917. To the baseband part, additionally a SIM card has been connected in which, amongst others, a so-called IMSI identifier has been stored which identifies the subscriber. Additionally the WLL terminal comprises an RJF part 913 and an antenna 914 for radio data transfer.
• the baseband part (BB) and the RF part of the WLL terminal can be implemented, for example, in the way shown in Fig. 8 by means of a mobile station.
• a line adapter 919 performs the adaptation between a subscriber device connection and a cellular telephone/radio part.
• the line adapter most commonly contains a microcontroller or similar control logic which is responsible for the recognition of DTMF (Dial Tone Multi-Frequency) characters, their conversion into messages to be sent to the baseband part BB and, for example, an analysis based on time-out or end character of the finishing of number selection, which it transmits to a cellular telephone, for example, through a serial interface depending on the manufacturer.
• the line adapter may comprise a power supply for supplying operating voltage to the baseband and RF parts of the terminal.
• Fig. 10 shows an optional WLL terminal 110 according to the invention wherein separate line adapters 116 and 117 have been used for analogue connection and they are controlled by the control unit of the baseband part 112.
• the baseband part 112 comprises a digital connection for a work station.
• the subscriber extension can be used simultaneously for speech connection and fax connection, for example, by means of separate traffic channel time slots reserved for these purposes.
• the capacity of the baseband part 112 is designed for the simultaneous coding of speech and data and for communication of two time slots on the radio channel.
• the application of the invention is not restricted to the GSM system shown as an example but it can be applied also in the context of other data transfer systems.
• the invention can actually be used preferably, amongst others, in GSM, PCN, DCS, UMTS or FPLMTS cellular systems or in WLL systems which have been implemented by means of these systems.
• the present invention is naturally applicable to be used also in High Speed Circuit Switched Data HSCSD wherein several parallel traffic channels are used for the same data connection in the radio interface.
• a telephone device, a facsimile device and a work station have been presented as subscriber devices, but the subscriber devices can naturally be other means of communication as well. Similarly, the number of subscriber devices and connections can also be greater than three. Additionally, more subscriber devices can be connected in parallel to one terminal connection when necessary.
• the invention is not either restricted to the described data services, protocols or applications, but these can all vaiy within the frame of the inventive idea.

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Mobile Radio Communication Systems (AREA)

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Publications (2)

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Cited By (4)

Citations (5)

• 1997
  • 1997-03-18 FI FI971131A patent/FI104224B/fi active
• 1998
  • 1998-03-17 WO PCT/FI1998/000234 patent/WO1998042153A2/en active Application Filing
  • 1998-03-17 GB GB9921971A patent/GB2341054B/en not_active Expired - Fee Related
  • 1998-03-17 DE DE19882192T patent/DE19882192T1/de not_active Withdrawn
  • 1998-03-17 CN CN98803518A patent/CN1251245A/zh active Pending
  • 1998-03-17 AU AU64037/98A patent/AU6403798A/en not_active Abandoned

Patent Citations (5)

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