FI101028B - A method for connecting a fixed network subscriber device, such as a telephone set, to a WLL system, as well as a radio unit and a radio network implementing the method. - Google Patents

Abstract

The invention relates to connecting a subscriber station (1) of a fixed network, such as a telephone set, to a WLL system. The radio unit (10, MS) to which a WLL subscriber station (1) is connected initiates connection and call set-up in the radio network immediately when the first digit is received from the subscriber station. Thus, the directory number of the called party is dialled simultaneously with setting up a signalling connection between the radio unit and the MSC in the radio network. The radio unit buffers the digits of the dialled directory number until the end of dialling. When the dialling has ended, the radio unit sends the directory number of the called party to the radio network (address command). As a result, the delay typically associated with the call set-up of a cellular radio network is minimized in WLL applications.

Description

, 101028

The invention relates to the connection of a fixed network subscriber device, such as a telephone set, to a radio network of a WLL system.

When building traditional fixed telecommunication networks, the most expensive and laborious part is cabling, which connects each subscriber to the local exchange. In many cases, it is advantageous to replace fixed ti broadband cables with a radio connection that can be easily and quickly set up to connect subscribers to the public switched telephone network (PSTN). In this case, the subscriber network comprises, like a normal radiotelephone network, base stations connected to the exchange, which are connected by radio to a permanently located radio unit. The radio unit, in turn, provides a traditional telephone interface to which any subscriber device in a fixed communication system, such as a voice-20 link, can be connected, whereby the radio path is invisible to the user and establishes a point-to-point connection between the telephone exchange and the telephone exchange. Such a system is called a Wireless Local Loop (WLL). Because the WLL radio system is usually an extension of a conventional public telephone network, it typically uses conventional telephone network numbering. Correspondingly, the call set-up from the subscriber end should, as far as possible for the user, correspond to the call set-up of the fixed telephone network, • 30 so that the radio connection is as "invisible" as possible.

In order to reduce design work and costs, it is advantageous to implement WLL networks using well-known radio network solutions, such as the pan-European mobile network GSM (Global System for Mobile Communica-35 tion) or the Nordic mobile network NMT (Nordic 2 101028

Mobile Telephone). The WLL network can even be implemented as part of a conventional mobile network, in which case there are both WLL subscribers and mobile subscribers in the same network. However, the call set-up 5 from the subscriber end of the mobile network does not as such correspond to the call set-up of the fixed telephone network. It has been possible to define on a case-by-case basis how it routes various calls to mobile switching centers. Typically, mobile switching centers are defined as a local number (telephone numbers beginning with 2-8 in Finland) means a telephone number within the mobile network. If the mobile subscriber wants the call to be routed out of the mobile network to the PSTN, then he must dial the area code in front of the recipient's PSTN number (9 in Finland). When making an international long distance call, the international country code (eg 990 or 999 in Finland) must be selected, followed by the country code, the national area code and the recipient's number according to the ISDN numbering. When calling from a landline telephone, the area code is not entered in front of the local number. 20 In other words, the user has to dial different Area Codes in the mobile network and the fixed network.

This leads to problems, especially in a mobile network where there are both ordinary mobile subscribers and WLL subscribers in the same base station area. In this case, the mobile network should be able to distinguish between local numbers requiring different routing of these subscribers, i.e. routing within the mobile network or routing according to PSTN numbering. The goal is that when a WLL subscriber dials a local call, it is routed to the PSTN. If, on the other hand, the WLL subscriber wants to call the mobile subscriber within the same mobile network, he should dial the area code of the mobile network in front of the recipient's number, as is usually the case when calling from the PSTN. After all, the WLL terminal must behave like a PSTN terminal.

35 Second, in the mobile network, after dialing the number 3 101028, the user must press a special "send" key before the call set-up is activated and an "end" key when the call is terminated. Fixed line telephones do not have "send" and "end" keys. In a fixed telephone network, lifting the telephone handset (off-hook) causes the subscriber loop to close, which is detected in the telephone exchange. As a result, the telephone exchange generates a dial tone in the subscriber loop. When the subscriber starts dialing the called party, dial tone generation center in June to October is terminated. If the call set-up fails or the recipient is busy, then the call center generates a busy tone for the subscriber loop. In the same way, the telephone exchange also generates other tones in the subscriber loop.

Thus, there is a need to implement an interface between a landline telephone 15 and a radio unit so that call set-up can be performed as far as possible in line with landline call set-up, i.e. using landline numbering, avoiding the "send" and "end" keys and supporting the landline 20 analogue tones that notify the caller of the progress of the call set-up.

EP patent application 0 569 314 discloses apparatus for connecting one or more conventional telephone sets to a cellular radio network. The apparatus comprises a radio unit 25 for a conventional telephone set. To make an outgoing call, the user picks up the handset, and when the adapter detects that the subscriber loop is closed, it makes a dial tone. Dial Tone when they hear the user selects the called party's telephone number. The dial tone is removed when the first 30 digits are dialed. The system decides that the selection is completed when a certain time has elapsed without new numbers being dialed. The call set-up to the radio network is then started. The call is terminated when the user hangs up. In this way, the fixed network voice device 35 can be used in a conventional manner even though it is connected to a cellular radio network.

U.S. Patents 4,658,096, 4,737,975 and 4,775,997 also provide an interface that connects a conventional telephone set to a cellular radio network transceiver. When the handset of the fixed telephone network 5 is picked up, the interface system detects the closure of the subscriber loop and generates a dial tone. The system converts the dialed voice or pulse dialing numbers, or digits, into digital data that is stored in the transceiver. 10 When all digits have been selected, the system automatically determines when the last digit occurred and outputs a transmission command signal to the transceiver. Upon receiving the transmission command signal, the transceiver transmits the telephone number converted into a bit string to the local exchange, which decodes the number and routes the number to the recipient. Also in this solution, the fixed network telephone set can be used in the usual way.

U.S. Patent No. 5,117,450 also discloses a cellular radio network telephone connected to a standard 20 fixed network telephone set. The cellular telephone includes a detector that examines the closing / opening of the subscriber loop and generates a dial tone when the subscriber loop closes. The DTMF indicator shows the numbers / characters dialed on the keypad and encodes and stores them in the memory. If 5 seconds have elapsed since the last character detected, then the cellular telephone checks whether the dialed number can be accepted, ie whether the dialed number contains enough characters or whether it is a special number, eg an emergency number. If the dialed number is in an acceptable format of 30, the stored telephone number is sent to the cellular network and call set-up is initiated.

In all the known solutions presented above, the signaling connection over the radio path is established only after the recipient's entire telephone number has been dialed 35 and a certain time has elapsed since the end of the selection. This 5 101028 after the formation of the signaling takes some time before the called party's telephone number can be transmitted over the radio path switching center. This results in a delay typical of cellular radio call set-up, which is further compounded by the delay used in the end-of-dial indication (up to 5 seconds). There is no such delay in fixed network call set-up. Therefore, the delay caused by call set-up should be minimized in the WLL system, so that the WLL system also corresponds as closely as possible to the fixed network in this respect as well.

The known solutions presented above also do not in any way take into account the incompatibility between the dialing of the fixed telephone network and the number of the cellular radio network, such as area codes.

EP patent application 0 530 010 defines a radiotelephone for use in a multinational mobile network, which includes a speed dial number memory. Telephone numbers can be entered into the speed dial number memory in the form U + M + T or K + T, where U = international code, M = country code-20 di, K s national remote code and T = area code + subscriber number. For each number entered, the radio adds the country code number C, even if it is a national number. When a call is made using a speed dial number, the radio first checks in which 25 countries it is currently registered to the network. If the telephone number corresponding to the speed dial number retrieved from the memory contains the code of the current country of residence, then this is a national call and the number is printed out in K + T format. If, on the other hand, the country code of the telephone number / 30 retrieved from the memory is different from the code of the current country of residence, then the telephone number is printed out in the form U + M + T, where U is the international code of the country where the telephone is registered. Only international numbers or national numbers with 35 area codes can be stored in the speed dial memory. The solution does not support the selection of the local telephone number in call set-up via the WLL system, where only international and domestic long distance calls are generally allowed.

U.S. Patent No. 4,473,720 defines an automatic dialer with separate fixed and movable parts. The fixed part contains the location identifiers, i.e. the international code, national code, country number and area code used at that location. The mobile part contains in its memory these same parameters as well as telephone numbers to which the dialer can make a call. Telephone numbers are structured as either local telephone numbers, national long distance numbers, or international long distance numbers. When the movable part is connected to the fixed part, the selector makes a comparison of the 15 location identification parameters. If there are any differences, the dialer modifies the telephone numbers in the memory of the mobile part according to the parameters from the local call number to the long distance number and vice versa. The dialer is intended for a fixed network and not for a WLL system where the call is established over a radiotelephone network. Thus, it does not in any way address the problem of supporting local telephone number dialing in call set-up over the radio network, where generally only foreign and domestic long distance numbers are allowed to be dialed.

It is an object of the present invention to alleviate the above problems by shortening the call set-up time in the WLL system and eliminating the inconsistency between the numbering used by the fixed network and the radio network.

The invention relates to a radio unit for connecting a fixed network subscriber device, such as a telephone set, to a radio network of a WLL system, which radio unit comprises 35 means for detecting the off hook of the fixed network subscriber device and is 7101028 hook states; means for generating beeps for the fixed network subscriber unit; detector fixed subscriber station of future valintadigit road, such as the called party number numerodigittien, 5 for detecting; the radio unit is adapted to the called party numerodigitit buffer the detected transmitting them to the radio network after the end of dialing. According to the invention, the radio unit is characterized in that the radio unit is adapted to initiate connection and call set-up in the radio network in response to detecting the first or first selection digits.

The invention relates also to a method puhelunmuodos, the stationary subscriber station, such as a voice-linkojeelta coupled to the WLL radio system 15 in the radio unit, the method comprising the steps of: a fixed network subscriber, the operator selects the called party number comprising a plurality of digittejä; the radio unit indicates to become fixed subscriber station dialing digits of the called party number; radio unit butt-20 roi selection digits until the end of the selection; the radio unit sends the called party number to the radio network after the end of the selection. The method according to the invention is characterized in that the radio unit starts the connection and call establishment in the radio network immediately after the detection of the first or first selection digits before the end of the selection.

The invention also relates to a WLL system comprising a radio network and a radio unit with which a fixed network subscriber device, such as a telephone set, is connected. 30 for a diode network, the radio unit comprising means for detecting off hook and on hook states of the fixed network subscriber unit; means for generating beeps for the fixed network subscriber unit; detector fixed subscriber station dialing digit future, such as a call-party number 35 of numerodigittien for detecting; 8 101028 radio unit is adapted to the called party numerodigitit buffer the detected transmitting them to the radio network after the end of dialing. The system according to the invention is characterized in that the radio unit 5 is responsive to the first dialing digit or the expression of connection and call setup in a radio network to initiate call set-up command which does not include the called party number; the radio network is arranged to initiate call set-secured only 10 of the subscriber data that the subscriber-puhelunmuodostuskomen not be approved without the called party number; the radio unit being arranged to transmit the number of the called party to the radio network special address message later during call set-up, when a selection has been completed; trans-15 radio network is arranged to start the call routing to the called party number, when receiving said address message.

In the invention, the radio unit to which a fixed subscriber apparatus is connected, the start of contacts 20 and the call-setup the radio network immediately when the fixed subscriber station selects the first number or mark of the called party's telephone number. In this case, the called party number can be entered in parallel with the call set up when the radio network form between the pre signaling connection 25 of the radio unit and the center. The radio unit buffers the digits of the selected phone number until the selection is completed. At the end of dialing, the radio unit sends the called party number to the radio network. The selection can be interpreted as ended when a certain time has elapsed since the expression of the last character v 30 or when a certain character indicating the end of the selection is expressed. When the end of the selection is inferred from the last number based on the elapsed time, which can be several seconds, the time benefit achieved by establishing a signaling connection in parallel with the selection 9101028 can be almost completely lost. The call set-up time can be kept to a minimum if the subscriber himself announces the end of dialing by entering a certain character, such as If both of the above methods are used to detect end-of-call simultaneously, both the advantage of fast call set-up can be achieved but the call set-up can continue. In the preferred embodiment of the invention in addition to the formation of a signaling link 10 is started in the actual call set-up before the end of dialing by sending from the radio unit to the radio network a call set-up message which does not include the called party's telephone number. With this solution, the call set-up time can be shortened more than by simply dialing in parallel and establishing a signaling connection. If only dialing and signaling connection are performed in parallel, the call set-up message is sent only after the entire telephone number has been dialed, which still causes a rather long delay before the call connection is established. If, on the other hand, some of the call set-up procedures are already performed during dialing and the telephone number is sent later in a separate address message, then the delay typically associated with call set-up in a cellular radio network can be further minimized.

According to a preferred embodiment of the invention, the support of the local number of the fixed network can be performed as follows. The mobile switching center automatically routes all local call numbers contained in the address message to the PSTN. That is, the mobile switching center infers directly from the use of the address message that it is a WLL ti wide and that the local numbers refer to the PSTN numbers. Thanks to this solution, the WLL subscriber can select a telephone number according to the numbering used in the fixed network, but the routing procedures 35 performed by the exchange can be stored in advance, for example in the GSM system. That is, mobile subscribers use a normal call set-up procedure and a standard call setup message.

The invention will now be described by way of preferred embodiments with reference to the accompanying drawings, in which Figure 1 shows a WLL radio system according to the invention, Figure 2 shows a block diagram of a WLL subscriber apparatus according to the invention comprising a fixed network telephone 14, an adapter and a radio network. Fig. 3 is a signaling diagram showing normal call set-up signaling of the GSM system in the case of an outgoing call, Fig. 4 is a signaling diagram showing call set-up signaling in the case of an outgoing call according to the invention, Fig. 5 is a flowchart illustrating the operation of the adapter 10 20 formation, Figure 6 is a flow chart illustrating operation of the MS according to the invention, an outgoing call setup, Figure 7 shows a SETUP message, the information element 25 "of the called party BCD number" structure, Figure 8 esitt s ADDRESS message in accordance with the invention of the structure.

The present invention can be applied to any radio system used to establish a WLL 30 (Wireless Local Loop) system to implement a wireless subscriber interface by replacing wired subscriber lines between a fixed telecommunications network, such as a telephone network, and its subscribers. The accompanying Figure 1 illustrates in principle a WLL system according to the invention based on the utilization of known radio networks, such as GSM. The WLL system can even be implemented as part of a conventional mobile network, in which case there are both WLL subscribers and mobile subscribers in the same network. In the following, the invention will be described using, but not limited to, the WLL network based on the pan-European digital mobile communication network GSM as an example.

The radio system shown in Figure 1 comprises an exchange MSC, a base station controller BSC, base stations BTS and 10 WLL subscriber devices 3, 4. For clarity, only one base station controller, two base stations and one subscriber device are shown in Figure 1, but naturally the number is large in a real network. The exchange MSC, like a conventional radiotelephone exchange, includes a switch for switching calls and a call control computer which controls all signaling between the subscriber devices and the radio network during call set-up, call and call termination and allocates radio channels for calls between the base station BTS and the subscriber devices 3, 4. The MS-20 radio system exchange MSC also has a connection 5 to the public switched telephone network PSTN 2 and through it to the PSTN subscribers 1 and to other networks 10 and their subscribers. The exchange MSC can be implemented directly as a local exchange of the public switched telephone network PSTN. The base station BTS can also be implemented like 25 conventional base stations. Its basic unit is, of course, a set of transceivers, the exact number of which is determined by the traffic capacity required.

The WLL subscriber unit typically consists of a radio unit 3 and a conventional fixed network subscriber unit • such as a telephone unit 4, a facsimile machine, a data modem, etc. The radio unit 3 acts as an interface to the radio path and provides the user with a normal analog 2-pair wide line. attaches its conventional speech-35 centrifuges 4. The structure of the radio unit will be described in more detail below in connection with Figure 2.

The WLL subscriber device is typically fixedly located at a particular location in the WLL system. Therefore, in WLL systems, the telephone number pu-5 of the subscriber device is fixedly associated with the location area formed by a particular base station BTS or several base stations in which the subscriber device is located. When a call comes in to a telephone number, the MSC initiates a paging of the subscriber unit by radio only in the BTS area of the base station in question or in the location area in question. Because the subscriber's location is assumed to be fixed, the WLL system does not require the mobility management functions and location update that are part of a normal mobile network. However, the radio system must have at least one subscriber base, for example a visitor location register VLR associated with the MSC 15, in which the subscriber information of the subscribers in the area of the exchange is maintained.

Figure 2 shows a radio unit 3 according to the invention, consisting of a radio system terminal 20 MS and an adapter 10. The adapter 10 forms a conventional analog 2-wire PSTN telephone connection 11 to which a PSTN subscriber device, such as a telephone set 4, can be connected. The DC power supply 12 generates the DC voltage required for the telephone connection subscriber loop, such as 12 V, 24 V or 25 48 V. The OFF / ON HOOK indicator 13 indicates that the subscriber loop is closed when the user picks up the handset (OFF HOOK) and the subscriber loop is opened when the user places the handset ON HOOK. The beep generator 14 generates the necessary beeps for the telephone connection 11, which inform the user of the various phases of the call. Such beeps include, for example, a dial tone, a busy tone, a ring tone, etc. The ringing voltage generator 16 generates a ringing voltage at the telephone interface 11 to alert the telephone 4 in the event of an incoming call. The detector 15 detects the selection digits of the two-tone multi-frequency 13 101028 (DTMF) received from the telephone device 4 in binary form for further processing in the controller 16. The detector 15 can also be a pulse selection indicator if the telephone set 4 uses pulse selection. All of the blocks 11-16 can be implemented in ways known per se and suitable practical solutions are described, for example, in U.S. Patents 4,737,975 and 5,117,450. The adapter 10 further comprises a microprocessor controller 17 to which the outputs of the detectors 13 and 15 are fed for further processing and 10 operation of the beeper 14 and the ring voltage generator 16. The controller 17 has a control interface 22 through which it sends selection digits and control signals to the radio unit MS and receives control signals from the radio unit MS.

The radio unit MS establishes a radio connection to the base station BTS of the radio network and all signaling related to the radio connection with the radio system. The radio unit MS is preferably the terminal of the radio system on which the implementation of the WLL system is based. In the exemplary case, the radio unit MS-20 is a terminal of the GSM system modified for operation according to the invention, as will be shown below. In the block diagram of Figure 2, the radio unit MS comprises only the basic components necessary for describing the invention. The transceiver block 18 si-25 includes a radio transmitter and receiver, modulation and detection, interleaving and deinterleaving, channel coding and channel decoding, speech coding, speech decoding, etc. The audio / data port 24 of the transceiver 18 is connected to the telephone terminal 11 of the adapter 10. the received audio / data • signal to radio frequencies and transmits the signal via the antenna 21 to the base station BTS. Correspondingly, the transceiver 18 demodulates the radio frequency signal received from the base station BTS into a baseband audio / data signal 35, which is fed via the port 24 to the telephone interface n 10102® 11. The operation of the radio unit MS is controlled by the microprocessor controller 20. The controller 20 generates signaling messages signaling messages received from the radio system via the transceiver 18. The controller 20 is connected to the controller 17 of the adapter 10 by a control interface 22, through which selection digitals and control signals are transmitted. In addition, the controller 20 is associated with a buffer memory 25 for temporarily storing selection digits and a timer 23 10 for indicating the end of the selection, as will be explained later.

Fig. 3 is a signaling diagram showing signaling commands in accordance with GSM Recommendations 04.08, version 4.7.0 in call set-up. 15 As mentioned earlier, the mobile communication network, this signaling is started only after pressing the called party number to select "send" key. This causes a delay in call set-up typical of mobile networks. Also in the known solutions, in which the telephone of the fixed network is connected to the terminal of the mobile communication system, the signaling connection and call establishment are started only after a certain time has elapsed after the end of the selection. The connection effect of these factors has caused a considerable delay in call set-up. The call set-up delay of the invention is shortened by starting call set-up as soon as the first dial digit is detected. In addition, the invention divides the SETUP command into two parts, which further shortens the call set-up delay. The call set-up according to the invention will be explained in more detail below with reference to Figures 4-8.

Fig. 5 is a flowchart illustrating the operation of the adapter 10 of Fig. 2. The detector 13 of the adapter 10 monitors the closing (OFF HOOK) and opening (ON HOOK) of the subscriber loop at the interface 11 (step 501). When the handset 35 of the telephone 4 is picked up, the subscriber loop closes (OFF HOOK) and the controller 1S 101028 17 commands the signal tone generator 15 to generate a dial tone connection 11 (step 502). The user of the telephone 4 is then expected to enter the first selection digit (number or character) in step 503. When the detector 5 detects the first DTMF digit and enters the corresponding binary value for the controller 17, the controller 17 generates a radio unit MS for the controller 20 "send "signal (step 504). At the same time, the first detected digit is transmitted to the controller 20. The second selection digit 10 is then waited for (step 505). When the controller 17 has received the second selection digit, it forwards the selection digit to the controller 20 and resets a timer 23 (step 506) which measures the time elapsed since the receipt of the second digit. In step 507, the controller 17 checks whether a new selection digit 15 has been received. If there is no controller 17, it is checked whether the reading of the timer 23 has reached a predetermined delay time T1 (step 508). If not, the process returns to step 507. If the timer 23 has reached a predetermined time T1, i.e. the time T1 has elapsed since the last digit selection 20, the controller 17 assumes that the selection has ended and generates a "selection end" signal for the radio unit controller 20.

If the controller receives a new digit in step 507, it checks whether the received digit is a specific en-25 character assigned by the user of the telephone 4 to indicate the end of the selection (step 509). By using the dial end signal, the maximum benefit is obtained that the signaling connection and call set-up are performed in parallel with the dial (after step 504). What is measured only by the time elapsed since the previous digit was typed (as in known solutions), a significant part of the advantage obtained by parallel connection is lost. However, in the preferred embodiment of the invention, in addition to the end signal, there is also a timer 23, 35 which ensures that call set-up is started at the latest after time T1 if the user forgets to enter the end signal. In a preferred embodiment of the invention, the end character is a "#" character. The "#" character is most appropriate because it does not appear in telephone numbers, and in additional-5 service commands it appears only in place of the first or second digit or as the last digit. In the invention, the check of the end character is performed only for the third and subsequent digits, whereby the "#" character in the first or second digit does not cause any problems. If the li-10 weather service command ends with a "#" character, then the character does not need to be entered twice.

If the digit checked in step 509 is a "#" sign, the controller 17 assumes that the selection is complete and generates a "end of selection" signal for the controller 20 (step 510).

If the received digit in step 509 is not a signal, the controller 17 forwards the digit to the controller 20 and proceeds back to step 506. The controller 17 continues in loop 506, 507, 508 and 509 to receive new digits until the timer 23 trips or a stop 20 "is received. # ".

Fig. 6 is a flowchart illustrating the operation of the radio unit MS according to the invention in establishing an outgoing call. In step 601 of FIG. 6, the controller 20 of the radio unit of FIG. . These procedures comprise signaling between the radio unit and the radio network according to GSM Recommendation 04.08, version 4.7.0 as illustrated in Figure 4.

This signaling includes, in the case of a successful connection, the messages "Channel request", "Immediate assignment", "CM service request", "Authentication request", "Authentication response", "Chipher mode command", 35 "Chipher mode complete" before the SETUP message. In the case of the SETUP message lv 101028, the invention differs from the signaling of GSM recommendation 04.08. GSM recommendation by the called party number is sent to the MSC in the SETUP message, which is transmitted in addition to information on the requested service, Bea 5-tert capability information element, which is defined in the GSM recommendation 04.08, version 4.7.0, Figures from 10.71 to 10.79. Since the invention yhteydenmuodostussignalointi start the WLL subscriber unit case, a CHANNEL REQUEST message as soon as the first digit is entered, then it is 10 likely that signaling has proceeded to sending a SETUP message to the called party's phone number is not yet completely been selected and not so known. However, the information on the requested service is available in the case of a normal call, as the GSM-15 subscriber unit formed by the radio unit stores information on the "Bearer Capability" parameters of the WLL device. If the WLL subscriber unit has more than one interface, for example a different interface for voice and data, then the "Bearer Capability" parameters can be configured separately for each interface. Thus, the radio unit selects the "Bearer Capability" parameters in the SETUP message according to what interface the WLL terminal uses. From the first character entered, it can be immediately deduced whether it is a normal call or an additional service command. If the first character (digit) is 25 numbers, then it is an ordinary call.

Thus, in the SETUP command according to the invention, all other information specified in the GSM recommendations can be sent except the recipient's number. The recipient number is normally transmitted in the "Called party BCD number" information element according to Figure 10.73 of GSM Recommendation 04.08, version 4.7.0, 30, which is also shown in Figure 7. The information element is a minimum of 3 octets long and a maximum of 13 octets long. Number of the called party is normally transmitted in octets 4-13. 35 the called party number may be omitted from this information element, the octets 101 028 18 4-13 is left out completely, and also sets the type number field to 000 (unknown), and the numbering plan identifier 0000 (unknown). These are the specifications according to the GSM Recommendation, and Figures-5 tu in Table 10.81 of GSM Recommendation 04.08, version 4.7.0.

Referring again to Figure 4, the SETUP message is followed by the GSM recommendation messages "Call proceeding", "Assignment command" and "Assignment complete", at which point the traffic channel is already reserved between the radio unit MS and the exchange MSC.

Simultaneously with the Signaling procedure described above, the radio unit controller 20 receives a selection digit from the adapter 10 one at a time (Fig. 6, step 603), stores the digit in the buffer memory 25 (step 15604), and checks whether the adapter 10 has received a "selection end" signal (step 60). ). Controller 20 continues in loops 603, 604 and 605 until all digits have been received and stored and adapter 10 has sent an "end of selection" signal. At step 606, the called party number 20 VED be transmitted by the MSC in a specific "Address command" message (Address command). This "address" message is transmitted according to the signaling scheme of Figure 4 after the traffic channel has already been allocated between the radio unit MS and the exchange MSC. In this way, the selection as well as the signaling connection and call set-up can be performed as parallel processes, which substantially reduces the call set-up delay typical of a mobile communication system. It should be noted that the "address" message is not sent in the case of an additional service command and not a normal call set-up.

Figure 8 shows a possible structure of an "address" message. The "address" message in Figure 8 is otherwise similar to the SETUP message defined in Table 9.70a of GSM Recommendation 04.08, version 4.7.0, but contains only two information elements: GSM-35 Recommendation 04.08, version 4.7.0, the 19101028 "Called party BCD number" information element of Fig. 10.73 and the "Called party subaddress" information element of Fig. 10.74. The latter is optional and is only needed in certain special situations. In addition, the "address-5 te" message contains a call control protocol discriminator = 0011, a transaction identifier = Oxxx (where x's are configurable by the radio unit MS), and its own message type, which is defined to have the same structure as other call set-up messages, i.e. 0x001100 -10 sit 04.04, version 4.7.0, Table 10.3). In the figure, IEI is an indicator of an information element.

The MSC is arranged to begin routing the call according to the called party to the called party's telephone number when it receives the above "osoi 15-you" message. In addition, in the signaling between the radio unit MS and the radio network, normal messages according to the GSM recommendation are sent after the "address" message to complete the call set-up: "Call proceeding", "Allert-ing", "Connect", "Connect acknowledge", as shown in Fig. 4 .

In normal call set-up from a fixed network subscriber unit, it is generally only permitted to dial foreign and domestic long distance numbers. According to a preferred embodiment of the invention, the support of the local number of the fixed network can be handled as follows. The MSC automatically routes all local call numbers contained in the "address" message to the PSTN. In other words, the mobile switching center infers directly from the use of the "address" message that it is a WLL-ti-30 wide and that the local numbers refer to the PSTN numbers. Normal mobile subscribers use the normal call set-up procedure and the standard call set-up message. Thus, the mobile switching center can conclude from the standard call set-up message that it is a mobile subscriber and that the local call numbers refer to numbers within the mobile network. Thanks to this solution, the WLL subscriber can dial the telephone number according to the numbering used in the fixed network, but the routing procedures performed by the exchange can be kept unchanged in the GSM system, for example.

Finally, a special case is considered in which the number selected from the WLL status device 4 has started with a character other than a number, i.e. it is an additional service command. In this case, call set-up is started as in Fig. 4 as soon as the first digit (character) is detected in the adapter 10 and the "send" signal is generated, but then the SETUP, "Facility" or "Register" message related to the additional services is sent from the radio unit to the MSC only when the controller 20 has received the "end of selection" signal from the adapter 10 15. This is done because it is not known which additional service is involved until the entire string has been entered. The last digit of the supplementary service commands is always "#", so the digit must, in addition to generating a "end of selection" signal, store the other 20 additional service command with the digits. Furthermore, since the additional service command must always end in the "#" digit, the "end of selection" signal cannot be triggered by time control. Time control can only be used to ensure that call set-up is aborted if the subscriber aborts the dial-25 nan before the final digit "#". Thus, the "Address" message is not sent at all in connection with additional service commands. The SETUP message, in turn, contains the so-called Facility information element described in Recommendation GSM 04.08 version 4.7.0 clause 10.5.4.15. In addition, the MSC can determine whether it further signals the supplementary service configuration information to the PSTN or whether it stores the information in the radio network's own database.

The accompanying figures and the related description are intended to illustrate the present invention only. Although the invention has been described with reference to certain embodiments, it is to be understood that the description is given by way of example only and that changes and modifications may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (11)

A radio unit for connecting a subscriber device (4), such as a telephone for a fixed network, to a radio network in a WLL system, the radio unit (10, MS) comprising means (13) for indicating off-hook and on-hook state of the fixed network subscriber apparatus, means (14) for generating signal tones to the fixed network subscriber apparatus, a detector (15) for indicating vai, such as number digit in the called party's number, which will from the fixed network subscriber apparatus, the radio unit is arranged to buffer the called party's indicated number digit so that they are transmitted to the radio network (BTS, BSC, MSC) only after the end of the election, characterized in that the radio unit is arranged to initiate connection and call connection in the radio network which response to detecting the first or first selection guitars. Radio unit according to claim 1, characterized in that the radio unit comprises a clock (23) which measures the time elapsed from detection of the last dialing unit, the radio unit being arranged to transmit the called party's number digit to the radio network where the time of the clock (23) matures achieves a predetermined time. Radio unit according to claim 1 or 2, characterized in that the radio unit is arranged to transmit the called party's number digit to the radio | the network immediately where a third or a later detected validity is a predetermined validity. Radio unit according to claim 1, 2 or 3, characterized in that the radio unit is arranged to initiate call connection in the mobile communication network with a call connection command (Figure 7) which does not contain the number of the called party, the radio unit is arranged to transmit the called the party's number in an additional address message (Figure 8) after the end of the election. A method of dialing from a fixed line subscriber apparatus, such as a telephone connected to a radio unit in a radio network in a WLL system, the method comprising the following steps the user of the fixed network subscriber dialing dials the called party's number comprising a plurality of digital, the radio unit detects the selection guitars coming from the fixed network subscriber apparatus in the number of the called party, the radio unit buffers the choice guitars to the end of the choice, the radio unit transmits the number of the called party to the radio network after the end of the choice, characterized by the radio unit initiating the connection. and call connection in the radio network immediately after detection of the first or first selection guitars before the end of the election. 25 6. A method according to claim 5, characterized in that the radio unit measures the time elapsed from detection of the last selection digit, the radio unit assuming that the selection is over when it; The measured time achieves a predetermined time. Method according to claim 5 or 6, characterized in that the user announces the end of the choice by means of a predetermined digital, the radio unit transmits the called party's number 28 101028 to the radio network immediately if a third or a later selected digit is said predetermined digit. Method according to claim 5, 6 or 7, characterized in that the radio unit initiates the call connection in the radio network with a call connection command which does not contain the number of the called party, the radio network initiates the call connection only after securing from the subscriber data that the subscriber's call connection is connected without the subscriber's call connection. number, the radio unit transmits the called party's number to the radio network in an additional address message later during call connection, after the end of the election, the radio network initiates the call's routing in accordance with the called party's number when it receives said address message. Method according to claim 8, characterized in that the local numbers contained in the address message are interpreted as numbers in a fixed telephone network and the call is routed to the fixed telephone network. Method according to claim 8 or 9, characterized in that the call dialing command is a SETUP message according to GSM Recommendation 04.08, in which the called party's number digit is omitted from the Called party BCD number information element, and the number type and numbering plan identifier are set to unknown, the address command contains at least the following information elements of the SETUP message according to GSM Recommendation 04.08: Call control discriminator, Transaction identifier, Message type, Called party subaddress. A WLL system comprising a radio network and a radio unit (10, MS) by means of which a subscriber apparatus (1), such as a telephone for a fixed network, is connected to the radio network, the radio unit comprising means (13) for detecting off-hook and on-hook state of the fixed network subscriber apparatus, means (14) for generating signal tones to the fixed network subscriber apparatus (1), a detector (15) for detecting selection guitars, such as number digits in the called party's number arriving from the fixed network subscriber apparatus, the radio unit is arranged to buffer the detected party's detected number digit so that they are transmitted to the radio network (BTS; BSC; MSC) only after the end of the election, characterized in that the radio unit is responsive to detection of the first or the first selection guitars for initiating connection and call connection in the radio network with a call connection command (Figure 7) that does not contain the called pair number, the radio network is arranged to initiate call connection only after having ensured from subscriber data (VLR) that the subscriber's call connection commands are accepted without the called party's number, the radio unit is arranged to send the called party's number to the radio network in an additional address message 1 they (Figure 8) later during call set-up, after the end of the election, the radio network is arranged to start the call's routing in accordance with the number of the called party when it receives said address message.