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METHOD FOR CONNECTING TELEPHONE
CALLS IN A MOBILE COMMUNICATION
The present invention relates to a method for answering 5 a telephone call coming to a mobile terminal in a situation where there is a packet-switched connection active in the mobile terminal, into which mobile terminal at least one reference item can be saved, and in which method a reception step is carried out, in which step information about the 10 incoming call is received to the mobile terminal. The invention also relates to a mobile terminal, which comprises means for answering an incoming call in a situation where there is a packet-switched connection active in the mobile terminal, which mobile terminal comprises means for saving 15 at least one reference item, and means for receiving information associated with the incoming call. Furthermore, the invention relates to a data transfer system comprising means for establishing a packet-switched connection between a mobile communication network and a mobile terminal, 20 means for initiating a telephone call between the mobile communication network and the mobile terminal, means for associating at least one identifier with the telephone call, and means for saving at least one reference item, and which mobile terminal comprises means for answering an incom- 25 ing call in a situation where a packet-switched connection is active in the mobile terminal.
The possibility to use packet-switched connections in addition to the common circuit-switched connections is being developed for mobile communication systems, such as 30 the GSM system. A General Packet Radio Service (GPRS service) is being developed to the GSM mobile communication system for implementing packet-switched connections. The GPRS service enables, among other things, the use of the Internet Protocol and the X.25 data transfer 35 protocol, short message service (SMS), e-mail transmission and wireless application protocol (WAP) applications. A packet-switched data transfer connection like this enables a data transmission method, which is more efficient than a circuit-switched connection, and which is especially suitable 40 for asynchronic data transfer, because in a packet-switched connection the resources of the mobile communication system are not allocated for the duration of the whole connection, but only for the time required for the transmission of the packets. As a contrast to this, in a circuit-switched 45 connection the connection is allocated for the whole time when the connection is active. By means of the packetswitched connection, the user of a mobile station can, for instance, keep an e-mail application activated all the time, whereby the user immediately detects an incoming e-mail 50 message. Because the packet-switched connection allocates resources only according to need, it may also offer lower cost of telephone calls compared to the use of a circuitswitched connection.
The GSM standard 03.60 version 6.2.0 chapter 5.4.5 55 presents three modes of operation for a mobile station of the GPRS system: class A, class B and class C. Mobile stations can be divided into these classes according to the types of packet network properties implemented in them. Mobile stations of class A can use the GPRS services and other GSM 60 services simultaneously. Mobile stations of class B can monitor the signals of the GPRS network and the control channel of the GSM network simultaneously, but they can use only either GPRS services or GSM services simultaneously. Mobile stations of class C can use a circuit- 65 switched connection and a packet-switched GPRS connection, but not simultaneously.
In practice, a mobile station of class B can receive pagings associated with initiating a circuit-switched connection even when the mobile station is using GPRS services, e.g. has an active packet-switched connection. Then the mobile station can receive a CS paging message notifying of an incoming call, for instance, but it cannot operate in a circuit-switched and a packet-switched connection simultaneously. Then if a message associated with a circuitswitched connection arrives in the mobile station, the packet-switched connection is set in a suspended mode for the duration of the reception of the message and a possible circuit-switched connection, until the circuit-switched connection has been terminated. In an ideal situation this means that the mobile station can switch its mode between a packet-switched connection and a circuit-switched connection, and after the switching resume the mode of operation in which the mobile station was when the interruption arrived. In practice, however, it has been found that applications using a packet-switched connection, such as e-mail or an FTP application used for file transfer, are disconnected even during a relatively short interruption. An interruption like this can be caused even by a break of a few seconds, such as signalling a circuit-switched telephone call to a level which enables alerting for the call.
One way of preventing the applications from being disconnected is to disable all circuit-switched call attempts during a packet-switched connection. Then, however, telephone calls which the user would like to receive even during a packet-switched connection are also disabled.
Another possibility is that the user can select whether to receive the incoming call or not. In the modern mobile stations it is possible to show information about the caller, such as the Caller Line Identity (CLI), which shows the calling number. Then the user can see from whom the call is coming and make his/her decision on the basis of that. However, this arrangement has the drawback that the time that passes from the arrival of the call signal to the decision about reception can be so long that the active application using a packet-switched connection can stop running.
It is an objective of the present invention to provide a method and a system in which it is possible to establish a circuit-switched connection during a packet-switched connection, when required. The invention is based on the idea that at least a first and a second priority class is specified, and a telephone number is classified as belonging to either of the priority classes, whereby, if the request to establish a circuit-switched connection comes from a telephone number belonging to the first priority class, the circuit-switched connection is established, but in other cases the circuit-switched connection is not established. The method according to the present invention is characterised in that it comprises at least the following steps:
an examination step, in which the information received about a telephone call is examined in order to find at least one item of identification information, and to find out if whether reference items have been saved in the mobile terminal, whereby if at least one reference item has been saved, a comparison step is performed in the method, wherein said at least one reference item and said at least one item of identification information found in the examination step are compared, and a decision step in which the decision about answering the phone call is made, and which decision is based on the comparison performed in said comparison step, if the comparison step was carried out. The mobile terminal according to the present invention is characterised in that it comprises at least:
examination means for finding at least one item of identification information from the information received, comparison means for comparing at least one reference item with the at least one item of identification information discovered in the examination means and for 5 producing a comparison result, and decision means for making the decision about answering the phone call on the basis of the comparison result produced by the comparison means. A data transfer system according to the present invention 10 is characterised in that it comprises at least:
examination means for finding at least one item of identification information from the information received in the mobile terminal, comparison means for comparing at least one reference item with the at least one item of identification information discovered in the examination means and for producing a comparison result, and decision means for making the decision about answering 20 the phone call in the mobile terminal on the basis of the comparison result produced by the comparison means. The present invention provides important advantages. When the method according to the invention is applied, disconnection of the packet-switched connection can be 25 avoided especially in situations where the request to initiate a circuit-switched connection comes from a telephone number classified to a lower priority group. In that case, the user is not disturbed, either, because no ringing tone is produced in these situations. However, the user can define important 30 telephone numbers, from which all incoming calls are connected regardless of whether the user has an active packetswitched connection or not. In a preferred embodiment of the invention, even in these situations the user can be given an opportunity to decide whether to receive the call or not. 35 When the packet-switched connection is not interrupted when less important phone calls are coming, the packetswitched connection is not as likely to be disconnected as in the prior art solutions. Thus the user can specify in advance from which telephone numbers interruptions to the packet- 40 switched connection are allowed.
In a method according to another preferred embodiment of the invention, the caller can, when required, specify whether the call is connected to the receiving number even in a situation that the receiver has an active packet-switched 45 connection. In this arrangement, passwords or other identifiers can be used, if required, to prevent unauthorised interruptions of the packet-switched connection.
In the following, the invention will be described in more detail with reference to the accompanying drawings, in 50 which
FIG. 1 shows a method according to a preferred embodiment of the invention as a simplified flowchart,
FIG. 2a is a simplified illustration of a mobile terminal embodying the invention, 55
FIG. 2b shows an example of specifying the priority class in a mobile terminal according to a preferred embodiment of the invention,
FIG. 2c shows an example of specifying a caller group in a mobile terminal according to a preferred embodiment of 60 the invention,
FIG. 3« shows an example of the caller's identification information saved in a mobile station according to a preferred embodiment of the invention,
FIG. 3b shows an example of caller groups saved in a 65 mobile station according to a preferred embodiment of the invention,
FIG. 4a shows a mobile terminal according to a preferred embodiment of the invention as a simplified block diagram, and
FIG. 4b illustrates a mobile communication system embodying the invention,
FIG. 1 shows the operation of a method according to a preferred embodiment of the invention in a mobile communication system NW1 as a simplified flowchart. The user has established a packet-switched connection to a mobile communication system with a mobile station MS. A mobile terminal MT can be, for instance, a mobile station with communication properties, such as the Nokia 9110 Communicator, or it can consist of a mobile station and a data processing device, between which a data transfer connection has been provided. An example of such a mobile terminal MT is a portable computer, which has a mobile station in card form, such as a GSM mobile station, connected to it. A mobile terminal MT comprises means for establishing both a circuit switched connection (CS) and a packet switched connection to a mobile communication system NW1.
FIG. 4a shows a mobile terminal MT according to a preferred embodiment of the invention as a simplified block diagram. Some operational blocks that are important for the description of the invention are shown in the figure. A mobile terminal MT includes a processor block CONTROL, which can be implemented by one or several processors, such as a microprocessor, a digital signal processing unit, etc., as known as such in the art. This processor block can also be implemented as a part of an Application Specific Integrated Circuit (ASIC), in which other operations of a mobile terminal can also be implemented. For saving information, the mobile terminal MT includes a memory MEM, such as read memory, read/write memory and/or non-volatile reprogrammable memory. The radio part RF comprises means for carrying out radio data transfer to the base transceiver station BTS. In addition, the mobile terminal MT preferably comprises a keyboard KB, a display DP and a display driver DD. In practice, a mobile terminal MT can be implemented in many different ways. A mobile terminal MT can be formed as one complete entity, such as the Nokia 9110 Communicator, or it can comprise a separate data transfer device, such as a mobile station, and a data processing device, such as a portable computer, whereby a local data transfer connection has been provided between these units.
FIG. 4b is a simplified block diagram of a mobile communication system NW1 embodying the invention. This mobile communication system NW1 comprises the properties of the GSM and GPRS mobile communication systems but naturally the invention can also be applied in other mobile communication systems, in which both packet switched and circuit switched connections are available. The blocks that are central to the operation of the mobile communication system NW1 are shown in FIG. 4b. The Serving GPRS Support Node (SGSN) controls the operation of the packet switching service on the side of the cellular network. The serving GPRS support node takes care of the attach to and detach from the network of the mobile station MS, updating the location of the mobile station MS and directing the data packets to the right addresses. The mobile station MS is connected to the base station subsystem BSS via a radio interface Um. The base station subsystem is connected to the serving support node SGSN via a BSSSGSN interface Gp. In the base station subsystem BSS, the base transceiver station BTS and the base station controller BSC are interconnected by a BTS-BSC interface called
Abis. The serving support nodes SGSN can communicate with other serving support nodes SGSN by means of the Gateway GPRS Support Node (GGSN).
The mobile stations communicate with the base transceiver stations BTS via the radio interface Um. The base 5 stations are controlled by Base Station Controllers (BSC), which have a data transfer connection to the Mobile Switching Centre (MSC). The base station controller BSC and the base transceiver stations BTS connected to it are also called the Base Station Subsystem (BSS). The connection interface 10 used in a circuit switched connection between a mobile switching centre MSC and a base station subsystem BSS is called the A interface. Correspondingly, the interface between a base station controller BSC and a base transceiver station BTS is called the Abis interface. The operations of a 15 mobile switching centre MSC include controlling the incoming and outgoing calls, like a telephone exchange of a Public Switched Telephone Network PSTN, (not shown). In addition, the mobile switching centre MSC carries out measures that are necessary in mobile communications, such 20 as the mobility management of the mobile station by means of e.g. a Home Location Register (HLR) and a Visitor Location Register (VLR): Via a mobile switching centre MSC it is also possible to establish a circuit switched connection to, for instance, the Internet data network NW2 25 preferably via one or more routers R2.
FIG. 3a shows an example of how the reference items used in determining the priority class can be saved in the mobile terminal MT. A telephone directory database DB1, for instance, has been formed in the memory means MEM, 30 in which database information ID of different persons/ companies etc., such as telephone number PN, name UN, caller group identification GNO and priority class CL1 has been saved. A telephone directory database DB1 can consist of many such items of directory information ID, as is known 35 a such. The telephone number PN is preferably saved as numbers. The name UN is saved as letters and possibly also numbers. The identifier of the caller group GNO is saved, for instance, as numbers. Thus the information of the caller group specified for a telephone number can be retrieved 40 from the caller group database DB2. A caller group is not necessarily specified for all the telephone directory information saved in the directory database DB1. In that case, however, the priority class can be saved in the priority class field CL1 of the directory database DB1. 45
FIG. 3b shows an example of how caller group information can be saved in a mobile terminal MT. A caller group database DB2 is preferably formed in the memory means MEM of the mobile terminal, in which database names of different caller groups GNM, the caller group identifiers 50 GNO and the caller group priority class CL2 have been saved. A caller group database DB2 can consist of many such items of directory information GNM, GNO, CL2, as is known as such.
The caller group identifier GNO is preferably saved as 55 numbers. The caller group name UN is saved as letters and possibly also numbers. The priority class CL1, CL2, is saved as numbers, for instance, or if there are two of the priority classes CL, the priority class CL1, CL2 can be saved in one bit, the value of which is set as either 0 or 1. The value 0 then 60 denotes e.g. the first priority class and the value 1 the second priority class.
It is obvious that other methods for specifying and saving information than those presented above in connection with the directory database DB1 and the caller group database 65 DB2 can be used in connection with embodiments of the invention.
The operation of a method according to a preferred embodiment of the invention will be described in the following. For example, the user has started an e-mail application or a WEB browser application with a data processing device. With the WEB browser application the user can examine, for instance, information contained in a server S, which is connected to the Internet data network NW2 via a router Rl and a local area network NW3, as is known as such in the art. The user can also receive an e-mail message sent from a workstation RH connected to a local area network NW3. A packet-switched connection has been activated in a mobile station MS, whereby information can be transmitted as packets between the mobile communication system NW1 and the mobile station MS, as is known as such in the art. This is illustrated by block 101 in the flowchart of FIG. 1. When a call is coming to the mobile terminal MS, e.g. from a telephone P of a public switched telephone network PSTN, a reception step is carried out in the mobile terminal, where, for instance, information about the incoming call is received. In addition, an examination step is carried out, where the caller identification information CLI transmitted in connection with the call, such as the calling telephone number, is examined. Preferably it is also examined in the examination step whether any reference items have been saved in the mobile terminal MS. If at least one reference item is found, the calling line identification information CLI is compared to at least one reference item saved in the mobile terminal MS, such as the information of the telephone directory database DB1 or corresponding information (block 102), preferably a telephone number PN. If a telephone number PN corresponding to the caller line identity CLI is found in the telephone directory database DB1, an examination step is preferably carried out (block 103), in which it is examined what the priority class specified for the telephone number PN is. This can be carried out so that it is examined at first in which caller group the telephone number belongs. If a caller group (e.g. the caller group identifier *0) has been specified in the telephone directory information, the caller group identifier GNO is retrieved from the directory data ID. On the basis of this caller group identifier GNO, the priority class CL2 specified for this caller group can be found out from the caller group database DB2. If a caller group has not been specified (e.g. the caller group identifier=0), the priority class specified for the telephone number PN is examined from the priority class information CLI of the telephone directory database DB1.
After that, a decision step is carried out in the method, in which step it is decided whether the call is answered or not. In the decision step, the priority class discovered in the examination step is preferably used as a criterion for the decision-making. If the priority class is the first priority class, operation continues from block 104. Then the mobile terminal MS sets the packet-switched connection in the suspended mode and produces a ringing tone to inform the user of the incoming call. At the same time, the mobile terminal MS can show the caller's telephone number or a corresponding name on the display. If the priority class specified for the caller is not the first priority class, or if there was no priority class information, operation moves from block 103 to block 105. Then the telephone call is not established, and as a response to the mobile communication system NW1 the mobile terminal MS preferably sends a User Determined User Busy (UDUB) signal. The packetswitched connection is then resumed normally (block 106). After the user has terminated the packet-switched connection, he/she is preferably notified of an arrived call, which was not answered, and possibly also of the telephone number CLI, from which the call was coming (block 107).