ENHANCEMENT OF MT CALL ESTABLISHING PROCEDURE

Abstract: The present invention provides a method of sending a message from a terminal to a communication network if said terminal is presently busy with at least one call, said method comprising the subsequent steps of establishing another call to said terminal within said communication network; and informing said communication network about the status of said terminal by sending a message from said terminal to said communication network, wherein said message contains an indication that a user of said terminal is busy with said at least one call.

Description: Enhancement of M call establishing procedure Field of the invention The present invention relates to a method of sending a message from a terminal to a communication network if this terminal is presently busy with at least one call. In particular, the present invention proposes therefor to enhance the mobile terminated call establishing procedure. Furthermore, the present invention relates to a communication network and a terminal for that purpose. Related Background Art In view of the upcoming modifications for communication networks like public land mobile networks and their related terminals due to the introduction of a GSM Phase 2+ standard (Global System for Mobile communications) and a UMTS standard (Universal Mobile Telephone System - the 3 rd generation, 3G) , respectively, there will be mobile phones usable as such terminals, which allow the utilization of several calls simultaneously, for example, one in a packet switched network and one in a circuit switched network. These terminals are called dual or multimode terminals. However, within or between these networks, no exchange of any information of user status takes place, and thus, if a call is established from a first communication network to a terminal, this first communication network cannot be aware of a status of this terminal which results from a connection within this first or to another (second) communication network. Specifically, if a user of a terminal is presently busy with at least another call or the resources of this terminal are running low due to at least one other call and a new call is established, the only thing the communication network recognizes if this terminal does not reply is that the user does not answer. The above described situation may be very likely to occur when handling packet switched data and the subscription to several circuit switched networks is possible, as will be the case at the latest after the introduction of the GPRS (General Packet Radio Service) and UMTS, respectively. For instance, packet switched connections may consume many of the terminals resources (as for example may be the case if image data is transferred) , particularly, if there is more than one connection, and users usually are not able to handle an unlimited number of speech calls (e.g. circuit switched) at one time, although the circuit switched multicall service of UMTS will allow a user to deal with several calls even of different communication networks. Hence, if the resources of the terminal are low or the user is too busy to accept further calls, a further call will not be accepted due to the fact that this would not be possible due to the resource shortage or priorisation. However, the calling party, i.e. its communication network, only recognizes that this terminal which is busy is not answering. This is a mistaken determination of the called party and can lead to some serious drawbacks. On one hand, there is a personal aspect of trying to call someone and getting the reply that the called party is simply not answering. This applies both to private contacts and to business contacts. In both cases, this may lead to a loss of such contacts, at least if this is more often the case. On the other hand, a communication network may provide a service what to do with an unaccepted call. However, the kind of such a service can depend on the kind of refusal of the call. Hence, if the communication network gets false or inadequate and thus misleading information of the user status, the wrong services are activated, resulting in incorrect and unwanted actions from the network side. The above mentioned consequences are also possible in this case. Summary of the present Invention Therefore, it is an object of the present invention to provide a mobile terminated call establishing procedure which is free from the above drawbacks. According to the present invention, this object can be achieved by a method of sending a message from a terminal to a communication network if said terminal is presently busy with at least one call, said method comprising the subsequent steps of establishing another call to said terminal within said communication network; and informing said communication network about the status of said terminal by sending a message from said terminal to said communication network, wherein said message contains an indication that a user of said terminal is busy with said at least one call. The object can also be achieved by a method of sending a message from a terminal to a communication network, said method comprising the subsequent steps of informing said terminal from said communication network that said communication network is about to establish another call; and informing said communication network about the status of said terminal by sending a message from said terminal to said communication network, wherein said message contains an indication if a user of said terminal is busy with said at least one call. Furthermore, the object is solved by a communication network comprising means adapted for a communication with terminals within said communication network; means adapted for a communication with terminals of said communication network and another communication network; and a device providing a multicall service for the handling of several simultaneous calls by one terminal of said communication network, wherein said multicall service device informs a calling terminal about a status of a called terminal of said communication network, if said called terminal is busy with at least one call. Moreover, the object is met by a terminal for the subscription to different communication networks, said terminal comprising means adapted for performing multicall handling; and means adapted for sending a message about the status of said terminal which message can be sent if said terminal is busy with at least one call. Advantageous further developments of the present invention are as set out in the respective dependent claims . Hence, it is an advantage of the present invention that both calling user and called user get more accurate information, which applies also to respective service providing devices of the communication networks. As these devices are thus properly informed about the actual user status, they can better serve the users. One example therefor is that the correct forwarding service is chosen if a call is not answered. By the same token, it is noted that any aspects described in accordance with the present invention form part of a fully automated process. That is, according to the present invention, any action in the present method or from the present communication network and from the present terminal, respectively, is automatically performed. However, it is to be noted that a user of the present terminal always can have full control over this automated process, e.g. by defining the presetting of the terminal and the terminal related services of the respective communication network, respectively. Preferred embodiments of the present invention are described herein below in detail by way of example with reference to the accompanying drawings. Brief description of the Drawings Fig. 1 shows a schematic diagram of the situation underlying the present invention; Fig. 2 shows a schematic diagram of a communication network according to the present invention being in connection with another communication network; and Fig. 3 shows a schematic diagram of the features which can be imparted to a terminal according to the present invention . Description of the Preferred Embodiments Referring now to Fig. 1, the situation underlying the present invention is that a user of a terminal Til is in principle able to subscribe to different communication networks, and the user of a terminal Til may be able to use more than one active channel simultaneously within one or more of those networks. As the present inventors expect this situation to become usual in the near future, the phrase "may" used before and in the following denotes this future case and is not intended to create doubt with respect to the circumstances of this situation, but indicate the possibility of slight changes within the illustrated principle. The above mentioned different communication networks may be a usual circuit switched communication network CS2, which can be a home network for the user, and a corresponding packet switched communication network PS2 for the transmission of non-speech data like multimedia messages, emails, facsimiles and so on, and speech data like voice over internet. Additionally, the user may be able to subscribe to other communication networks, which also may be either circuit switched or packet switched. With respect thereto, it may be of course possible that the user of the terminal Til is contacted from another communication network, for example, from a terminal T12 from another circuit switched communication network CS1. However, it is to be noted that presently, in UMTS, circuit switched multicall means the case where more than one circuit switched call from one circuit switched network can be in active state with one terminal simultaneously. A third network connection might be possible as is conceivable according to the present invention, but this is not the basic approach of circuit switched multicall. In the present description, the more common approach is used to illustrate the full scope of the present invention, therein bearing in mind that the intended UMTS approach is included therein. Depending on the resources of the terminal Til, its user is able to handle several calls at one time. This may be one or more calls for the transmission of packet switched data, for example, a call connection C14 to a facsimile terminal T14 and/or a call connection C15 to a computer terminal T15. While these packet switched calls can be performed in the background by the terminal Til due to a manual interaction of its user or an automated procedure set by the user, she or he may call or be called in a circuit switched connection by a terminal T13 within a circuit switched communication network CS2 or by a terminal T16 within a circuit switched communication network CS1. In this connection, it is noted that when the GSM phase 2+ standard will be introduced, the simultaneous handling of packet switched and circuit switched calls will most likely be set up to a wide extent, and the suitable terminals for that purpose are denoted as class A (simultaneous handling of GSM calls and GPRS calls) and class B (operating only one set of services at one time) terminals. In the 3 rd generation of communication networks and their respective terminals, circuit switched multicall is intended to be introduced as mentioned above, which makes the simultaneous handling of circuit switched calls possible. Thus, also the terminals for UMTS will be adapted to that extent. As can be gathered from the foregoing, the amount of resources available in a terminal are a critical parameter for the extent of a possible use of these new features. However, apart from the above given specific definitions of standards to come, the present invention intends to deal with the outlined problem in a most general way, while the herein included references to existing or upcoming standards are only to be understood as embodiments of the present invention. Having further regard to Fig. 1, it is now fully clear that besides the existing call connections C14, C15, and C13 or Clβ of the terminal Til, it is conceivable and probably in near future very likely that a further call C12, particularly a circuit switched call having speech data contents, is established to the terminal Til. Specifically, this call C12 might be established in a communication network CSl within which another call Clβ is already present, or which communication network CSl is different from a communication network CS2 within which another circuit switched call C13 is active. Anyway, the communication network CSl is not aware of calls being active within it, or even more, being active within other communication networks CS2, PS2. As mentioned above, despite the possibility to handle multiple calls, the sooner or later a point will be reached, when either the resources of the terminal Til or the "capacity" of the user will run short. The result would be that the call C12 is not accepted by the terminal Til or its user, although terminal Til is registered as being present in the communication network CSl in which the call C12 is established. Accordingly, what the communication network CSl "knows" on its own is that the terminal Til is present in the network and that the user is not answering. However, the communication network CSl will not eternally try to reach terminal Til, but rather activate a predetermined service after the expiry of a predetermined time period what to do with the call C12 from the terminal T12 to the terminal Til. The kind of service strongly depends upon the reason for which the call was not answered. In this connection, one should bear in mind that this reason is not only transported to technical devices, but can also be apparent to a human user of the terminal T12. According to the present invention, since the communication network CSl cannot obtain on its own the true status of the terminal Til and thus the true reason why the user of the terminal Til is not answering, the terminal Til informs the communication network CSl with a message about the present status of the terminal Til, if the user of the terminal Til is presently busy with another call. Therefore, according to the present invention, more accurate information is present within the communication network CSl, resulting in a proper activation of corresponding services and giving a pardonable reason to the user of terminal T12, be it a business or private relationship, why the user of terminal Til is not answering. This is in strong contrast to the prior art, where a false evaluation by the communication network CSl of the fact that the user of terminal Til is not answering can lead to severe failures, which might damage such business or private relationships. Another embodiment according to the present invention is that if a user of a terminal T12 within a certain communication network calls a user of a terminal Til within a certain communication network, be it the same as that of terminal T12 or another, then the certain communication network of terminal Til informs the terminal Til, for example with a message, that it is about to establish a connection to terminal Til. It is expressly mentioned that this informing is done before the actual establishing of the call from the certain communication network of terminal Til and the terminal Til is executed. Consequently, as an answer to that informing of the communication network to which terminal Til presently subscribes to, said terminal Til informs its communication network back whether it does have free resources to accept another call or not. Via an interaction of the user of terminal Til it is also possible to include the case that she or he may inform about the case "too busy to accept another call" (busy with another call) . As a result, if terminal Til informs that it does not have free resources or that its user is busy with another call, then the call of terminal T12 will not be established from the certain communication network of terminal Til at all. This is in contrast to the above case where the establishing procedure is aborted if the terminal informs that it does not have free resources. The modifications and additional features of this embodiment can all be the same as in the above embodiment. Moreover, very likely advantages occur. In all of the foregoing, the expression "communication network" is used for the sake of simplicity instead of naming the specific devices and means of a communication network being responsible for the respective functionalities mentioned above. The reason is that the description of the present invention is hitherto not related to such devices. In contrast thereto, in the following, there will be described the basic means of a communication network necessary for carrying out the present invention. As can be gathered from Fig. 2, a communication network Nl according to the present invention comprises means 21 for enabling a communication between a terminal Til of the communication network Nl and a terminal T22 of another communication network N2. Furthermore, means 24 are present in the communication network Nl for a communication between a terminal Til and another terminal T12, both within the communication network Nl . The other communication network N2 could also be a typical fixed line telephone network (POTS). Incoming calls in the communication network Nl are processed by a gateway functionality of the means 21 while outgoing calls from the communication network Nl are processed by an interworkmg functionality. In common public land mobile networks these functions are included in a respective mobile services switching center MSC. For a communication between networks, another communication network N2 also has to have means 22 for such a purpose which would basically correspond to the means 21. For offering a multicall service to the user of the terminal Til, the communication network Nl has to comprise a device 23 which provides that service. Accordingly, this device is responsible for delivering the message indicating that the user of the terminal Til is busy with another call. However, this device 23 can be implemented in another device of the communication network Nl, that is, the present invention is not directed to the location of this device 23. Anyway, with the device 23 being present in the communication network Nl, the terminal Til is able to inform another terminal T12, T22 being present within the communication network Nl or within another communication network N2, respectively, that the user of terminal Til is busy with another call, if a terminal T12, T22 intends to establish a call to terminal Til. With respect thereto, according to the present invention, the terminal Til comprises means MCM adapted for performing multicall handling, and means MSM adapted for sending a message about the status of said terminal Til, e.g. in a case when said terminal Til is busy with another call, as shown in Fig. 3. The terminal Til may further comprise means CSM for processing circuit switched data and/or means PSM for processing packet switched data. Consequently, the terminal Til is able to subscribe to different communication networks, wherein it accurately interacts with other terminals of those different communication networks. Thus, provided services are accurately informed and properly performed. It is expressly to be noted that the described examples with respect to the number and kind (packet or circuit switched) are not intended to limit the present invention, but are only intended to illustrate the present invention. While in the foregoing the present invention has been described in principle by way of example with reference to possible embodiments, some implementations are listed hereinafter which are to be understood as concrete embodiments of the present invention which include further generally valid descriptions of the present invention . Namely, the specification GSM 04.08 "mobile terminating call establishment" defines an information element 'cause' in a CALL CONFIRMED message, which is also described therein. A proposal for implementing the present invention is to change the rule set out in chapter 9.3.2.3 of specification GSM 04.08 to support the multicall cases, where a user may be busy with another call, although in the respective terminal still free capacities and free circuit switched or packet switched connections are available. Specifically, the CALL CONFIRMED message should include the information element 'cause' with #NN "user busy with another call". The value of NN should be selected in conformance with the GSM rules for error message numbering. After this message has been sent, the respective terminal should stay in a "mobile terminating call confirmed " state as the rule in chapter 5.2.2.3.1 of specification GSM 04.06 specifies . It is noted that according to the present invention the terminal should be allowed to send the information element 'cause' with #NN "user busy with another call" also in cases where the terminal's hardware limitations or a shortage of power prevent the receiving of any new call by the terminal. By such an implementation, all of the above effects and advantages would be obtained. The utilization of this new information element by a communication network can be seen from the following examples. If the communication network receives the CALL CONFIRMED message with the information element 'cause' #NN "user busy with another call", and the supplementary service 'call forwarding when user is busy 1 is activated, then after the expiration of a timer, the communication network would forward the call as specified m connection with the user busy case. The result is that 'call forwarding when user busy' serves as its original purpose is, although it was activated after the expiration of a timer, which originally indicates that a user has not answered within reserved time. Furthermore, if a communication network receives the CALL CONFIRMED message with the information element 'cause' #NN "user busy with another call", then after the expiration of a timer, the communication network would initiate clearing procedures towards the calling user with the information element 'cause' #NN "user busy with another call" instead of the cause presently specified #19 "user alerting, no answer". The effect is in this case that a communication network can inform a calling user that a called user is busy as really is the case, although the expiry of a timer originally means that a called user has not answered or did not wanted to answer within time. With this information, the communication network can also activate proper call forwarding services, providing both the calling user and the called user a clearly better service . As a further embodiment of the present invention it is additionally conceivable that the rejection of a call within the complete range described above could be based on the priority of the on-going call(s). This means that if the on-going call is, for example, a low priority download in the GPRS network, a GSM call could be connected while the GPRS call is suspended. As described above, the present invention proposes a method of sending a message from a terminal Til to a communication network CSl if said terminal Til is presently busy with at least one call C13, C14, C15, Clβ, said method comprising the subsequent steps of establishing another call C12 to said terminal Til within said communication network CSl; and informing said communication network CSl about the status of said terminal Til by sending a message from said terminal Til to said communication network CSl, wherein said message contains an indication that a user of said terminal Til is busy with said at least one call C13, C14, C15, Clβ. It should be understood that the above description and accompanying figures are only intended to illustrate the present invention by way of example. The preferred embodiments of the present invention may thus vary within the scope of the attached claims.

Claims: Claims 1. A method of sending a message from a terminal (Til) to a communication network (CSl) if said terminal (Til) is presently busy with at least one call (C13; C14; C15; C16) , said method comprising the subsequent steps of establishing another call (C12) to said terminal (Til) within said communication network (CSl) ; and informing said communication network (CSl) about the status of said terminal (Til) by sending a message from said terminal (Til) to said communication network (CSl) , wherein said message contains an indication that a user of said terminal (Til) is busy with said at least one call (C13; C14; C15 ; C16) . 2. A method according to claim 1, wherein said message confirms said other call (C12) and includes an information element. 3. A method according to claim 2, wherein said information element has a value indicating that said user of said terminal (Til) is busy with said at least one call (C13; C14; C15; C16) . 4. A method according to claim 1, wherein said message is sent in case that free resources of said terminal (Til) do not allow the acceptance of another call (C12) . 5. A method according to claim 1, wherein if free resources of said terminal (Til) would allow the acceptance of another call (C12) , said message is sent after the expiry of a predetermined time period. 6. A method according to claim 4 or 5, wherein said other call (C12) within said communication network (CSl) is forwarded when said message is sent. 7. A method according to claim 4 or 5, wherein said other call (C12) within said communication network (CSl) is cleared when said message is sent. 8. A method according to claim 1, wherein if free resources of said terminal (Til) would allow the acceptance of another call (C12) , said message is sent if a priority of said other call (C12) is lower than a threshold value. 9. A method according to claim 8, wherein said threshold value is a priority value of said at least one call (C13; C14; C15; Clβ) which is on-going. 10. A method of sending a message from a terminal (Til) to a communication network (CSl) , said method comprising the subsequent steps of informing said terminal (Til) from said communication network (CSl) that said communication network (CSl) is about to establish another call (C12) ; and informing said communication network (CSl) about the status of said terminal (Til) by sending a message from said terminal (Til) to said communication network (CSl) , wherein said message contains an indication if a user of said terminal (Til) is busy with said at least one call (C13; C14; C15; C16) . 11. A method according to claim 10, wherein said message is sent in case that free resources of said terminal (Til) do not allow the acceptance of another call (C12) . 12. A method according to claim 10, wherein if free resources of said terminal (Til) would allow the acceptance of another call (C12) , said message is sent after the expiry of a predetermined time period. 13. A method according to claim 11 or 12, wherein said other call (C12) within said communication network (CSl) is forwarded when said message is sent. 14. A method according to claim 10, wherein if free resources of said terminal (Til) would allow the acceptance of another call (C12) , said message is sent if a priority of said other call (C12) is lower than a threshold value. 15. A method according to claim 14, wherein said threshold value is a priority value of said at least one call (C13; C14; C15; Clβ) which is on-going. 16. A communication network comprising means (24) adapted for a communication with terminals within said communication network (Nl) ; means (21) adapted for a communication with terminals of said communication network (Nl) and another communication network (N2) ; and a device (23) providing a multicall service for the handling of several simultaneous calls by one terminal (Til) of said communication network (Nl) , wherein said multicall service device informs a calling terminal (T12) about a status of a called terminal (Til) of said communication network (Nl) , if said called terminal (Til) is busy with at least one call (C13; C14; C15; Clβ) . 17. A network according to claim 16, wherein said network (Nl ; PS2) allows the transmission of packet switched data . 18. A network according to claim 16, wherein said network (Nl ; CSl; CS2) allows the transmission of circuit switched data. 19. A terminal for the subscription to different communication networks (CSl, CS2 , PS2) , said terminal (Til) comprising means (MCM) adapted for performing multicall handling; and means (MSM) adapted for sending a message about the status of said terminal (Til) if said terminal (Til) is busy with at least one call (C13; C14; C15; Clβ). 20. A terminal according to claim 19, further comprising means (CSM) for processing circuit switched data. 21. A terminal according to claim 19 or 20, further comprising means (PSM) for processing packet switched data .

Inventors: RUUSKA PEKKA, RUUSKA, PEKKA
Applicants: NOKIA NETWORKS OY, RUUSKA PEKKA, RUUSKA, PEKKA
Application year: 1999
Main classification: H04Q7
IPC codes: H04W4, H04W76