WO2008041798A1

WO2008041798A1 - Method for transmitting legacy service message through internet protocol multimedia subsystem network and user equipment therefor

Info

Publication number: WO2008041798A1
Application number: PCT/KR2007/004428
Authority: WO
Inventors: Woo Jun Ye; Kang Suk Huh; Masson Romain; Narasimha Murthy Prakash; Tae Soon Choi
Original assignee: Lg Electronics Inc.
Priority date: 2006-10-02
Filing date: 2007-09-13
Publication date: 2008-04-10

Abstract

Provided a method of transmitting a legacy service message in an IP multimedia subsystem (IMS) network and a user equipment therefor. The user equipment includes a client control function (CCF). When receiving a request for a message transmission service from a user, the CCF transmits a legacy service message to a server by determining a transport type depending on the kind of the requested service and transmitting a transmission message, which includes the legacy service message acquired in cooperation with a legacy service client, to a server control function (SCF) in accordance with a transport protocol corresponding to the determined transport type. In this case, a session initiation protocol (SIP) message and/or an SIP based protocol message can be used as the transmission message.

Description

METHOD FOR TRANSMITTING LEGACY SERVICE MESSAGE THROUGH INTERNET PROTOCOL MULTIMEDIA SUBSYSTEM NETWORK AND USER EQUIPMENT THEREFOR

Technical Field

[1] The present invention relates to a message transmission method, and more particularly, to a method of transmitting a legacy service message in which different types of messages (legacy service messages) used in various services can be transmitted through an internet protocol multimedia subsystem (IMS) network by the use of the same method, and a user equipment therefor. Background Art

[2] The IMS has attracted attention as a core information communication technology for providing a new multimedia service in an IP (Internet Protocol) based next- generation communication environment. The IMS is a set of nodes which provide various multimedia services in a mobile communication network and which perform a call control operation and unifies the IP network and the mobile communication network. Accordingly, the IMS facilitates mutual operation between a user equipment and the IP network and thus can provide an IP based multimedia service using the user equipment.

[3] The services provided through the IMS network in which the IP network and the mobile communication network are unified can be roughly classified into a message service, a voice service, and a video service. The message service includes a short message service (SMS), a multimedia message service (MMS), an E-mail service, a SIMPLE-IM (SIP for Instant Message and Presence Leveraging Extensions-Instant Message) service, and an IMPS (Instant Message and Presence Service). The voice service includes a VoIP (Voice over IP) service and a PoC (Push-to-talk over Cellular) service. The video service includes a Video_oIP (Video-over IP) service.

[4] Such services have independent protocol silos for transmitting the messages. That is, the messages are transmitted using transport protocols specific to the respective services. The transport protocols used in the services are listed in Table 1.

[5] Table 1

[6] With the fastest growth of the IMS network as a next-generation core information communication technology, there is a need for providing the above-mentioned various services in the IMS network in a unified manner. A unified message transmission method of transmitting various legacy service messages is required to satisfy the need, but no specific message transmission method has been suggested. Therefore, there is as ever a need for providing the various services as a unified service in the IMS network. Disclosure of Invention Technical Problem

[7] An object of the invention is to provide a method of transmitting a legacy service message in which various legacy service messages can be transmitted in a unified manner in an IMS network so as to provide various services, which have been provided in accordance with independent transport protocols, as a unified service in the IMS network and a user equipment therefor.

Technical Solution

[8] According to an aspect of the invention, there is provided a message transmission method of transmitting a message from a controller which interworks with one or more legacy service message processing modules, the message transmission method including the steps of: receiving a request for transmitting a legacy service message; and determining a message transport type on the basis of a kind of the requested legacy service message and transmitting a transmission message, which includes the requested legacy service message, to a server in accordance with a transport protocol corresponding to the determined message transport type.

[9] According to another aspect of the invention, there is provided a message transmission method of transmitting a message from a controller which interworks with one or more legacy service message processing modules, the message transmission method including the steps of: receiving a request for transmitting a legacy service message; and transmitting a transmission message, which includes the requested legacy service message, to a server in accordance with a transport protocol of a transport type corresponding to the requested legacy service message among transport types classified based on kinds of the legacy service messages.

[10] According to still another aspect of the invention, there is provided a method of transmitting a legacy service message in an IP multimedia subsystem (IMS) network by the use of a server control function (SCF), the method including the steps of: receiving a first transmission message including the legacy service message; and processing the legacy service message by interworking with a legacy service server (LSS) corresponding to service type information of the legacy service message and transmitting a second transmission message including the processed legacy service message. In this case, the service type information may be received or transmitted in a state where it is contained in the first and/or second transmission message or may be received or transmitted in a state where it is contained in a message other than the first and/or second transmission message.

[11] According to still another aspect of the invention, there is provided a message transmission method including the steps of: receiving, by a first client control function (CCF), a request for transmitting a legacy service message and requesting a first legacy service client (LSC) corresponding to a transport type information of the requested legacy service message for generating the requested legacy service message; transmitting a first transmission message, which includes the legacy service message generated and received from the first LSC, from the first CCF to the SCF in accordance with a transport protocol corresponding to the transport type information; processing the received first transmission message, extracting the legacy service message therefrom, and transmitting the extracted legacy service message from the SCF to a legacy service server (LSS) corresponding to the service type information; and transmitting a second transmission message, which includes the legacy service message processed by the LSS and received from the LSS, from the SCF to a second CCF.

[12] According to still another aspect of the invention, there is provided a method of transmitting a legacy service message in an IMS network, the method including the steps of: setting up a first SIP session between a first client control function (CCF) and a server control function (SCF); transmitting a first transmission message, which a legacy service message acquired by interworking with a first legacy service client (LSC) supporting a service requested to the first CCF is inserted into, from the first CCF to the SCF through the first SIP session; and acquiring the legacy service message processed by interworking with a legacy service server (LSS) for processing the legacy service message and transmitting a second transmission message, which the processed legacy service message is inserted into, from the SCF to a second CCF.

[13] According to still another aspect of the invention, there is provided a method of transmitting a legacy service message in an IMS network from a client control function (CCF) interworking with a plurality of legacy service clients (LSCs), the method including the steps of: acquiring the legacy service message by interworking with the LSC supporting a requested service among the plurality of LSCs; and adaptively transmitting a transmission message, which includes the acquired legacy service message, in accordance with a transport protocol corresponding to the type of the requested service.

[14] According to still another aspect of the invention, there is provided a method of setting up a session for providing a bidirectional conversation service using an SCF in an IMS network, the method including the steps of: setting up a first SIP session in cooperation with a first user equipment in reply to a first session initiation request message received from the first user equipment; receiving a first transmission message, which includes a conversation invite message acquired by interworking with a first LSC taking charge of the bidirectional conversation service of the first user equipment, from the first user equipment through the first SIP session; setting up a second SIP session in cooperation with a second user equipment; processing the conversation invite message by interworking with an LSS for managing the bidirectional conversation service and transmitting a second transmission message, which includes the processed conversation invite message, to the second user equipment through the second SIP session; receiving a third transmission message, which includes a reply message to the conversation invite message acquired by interworking with a second LSC taking charge of the bidirectional conversation service of the second user equipment, from the second user equipment through the second SIP session; and processing the reply message by interworking with the LSS and transmitting a fourth transmission message, which includes the processes reply message, to the first user equipment through the first SIP session.

[15] According to still another aspect of the invention, there is provided a user equipment including: one or more legacy service client (LSC) modules; and a client control function (CCF) for determining a transport type from a requested service and transmitting a transmission message, which includes a legacy service message acquired by interworking with the LSC module taking charge of the requested service among the LSC modules, in accordance with a transport protocol corresponding to the determined transport type.

Advantageous Effects

[16] In the method of transmitting different types of messages in the IMS network according to the invention, it is possible to provide various services, which have been provided in accordance with independent transport protocols, in the IMS network in a unified manner.

Brief Description of the Drawings [17] Fig. 1 is a block diagram illustrating a system used to explain a method of transmitting a legacy service message in an IMS network according to an embodiment of the invention. [18] Fig. 2 is a block diagram illustrating a system used to embody a method of transmitting a legacy service message between two user equipments in an IMS network according to an embodiment of the invention. [19] Fig. 3 is a diagram illustrating a message flow in a method of transmitting an SMS message in an IMS network according to an embodiment of the invention. [20] Fig. 4 is a diagram illustrating a message flow in a method of transmitting an MMS message in an IMS network according to an embodiment of the invention. [21] Figs. 5 and 6 are diagrams illustrating a message flow in a method of transmitting a

SIMPLE-IM service message in an IMS network according to another embodiment of the invention. [22] Fig. 7 is a block diagram illustrating a system used to embody a method of transmitting a legacy service message between a user equipment and a legacy service client in an IMS network according to an embodiment of the invention. [23] Fig. 8 is a block diagram illustrating a system used to embody a method of transmitting a legacy service message between user equipments connected to different

IMS networks according to an embodiment of the invention.

Best Mode for Carrying Out the Invention [24] Transport protocols or signaling protocols which can be used in a method of transmitting a legacy service message in an IMS network according to the invention will be described before concrete embodiments of the invention are described.

However, the signaling protocols to be described later are only for exemplary purpose and the invention is not limited to the signal protocols. That is, signaling protocols different from the signaling protocols to be described later may be used as long as they are functionally equivalent or similar to each other. [25] A session initiation protocol (SIP) is known as one of the signaling protocols which can be used in an IP based multimedia service over an IMS network. The SIP is a call control protocol of an application layer for searching for a position of a communication opposite and generating, correcting, and ending an IP based multimedia service session between user equipments or between a user equipment and an entity having an IP address. [26] In an embodiment of the invention, an SIP message and/or an SIP based protocol message is used to transmit various types of legacy service messages in the IMS network. The SIP based protocol message may be a message (MSRP message) based o n a message session relay protocol (MSRP). In general, the MSRP message is simpler than the SIP message, is transmitted through the set-up SIP session, and is under the congestion control of a transmission control protocol (TCP). Accordingly, by using the MSRP message, it is possible to transmit a message having a larger size in comparison with a case using the SIP message.

[27] In a method of transmitting a legacy service message according to an embodiment of the invention, a message can be transmitted using one of three types of transport protocols to be described below. Three types of transport protocols are referred to as a first transport protocol, a second transport protocol, and a third transport protocol for the purpose of convenient description.

[28] According to the first transport protocol, a legacy service message is transmitted from a functional entity to a second functional entity by the use of one of various types of SIP messages such as an SIP MESSAGE. That is, a message is transmitted by the use of a unidirectional SIP message method.

[29] The SIP MESSAGE can be transmitted along with information on a service type

(service type information) of a service requested from a user. For example, by inserting a legacy service message into a body portion of the SIP MESSAGE and containing the service type information in a header portion or a body portion of the SIP MESSAGE, the service type information and the legacy service message are transmitted together. In this case, the legacy service message can be inserted into the body portion without any correction.

[30] In this way, according to the first transport protocol, since the legacy service message is transmitted using the SIP message, the size of a message which can be transmitted using the first transport protocol can be limited. That is, when a message using the first transport protocol is transmitted, a message larger than the message which can be contained in the body portion of the SIP message such as an SIP MESSAGE cannot be transmitted. Accordingly, the first transport protocol is suitable for transmitting an SMS message or a message having a small size such as a notification message generated by a legacy service server (LSS) or the like.

[31] According to the second transport protocol, a unidirectional legacy service message is transmitted from the first functional entity to the second functional entity by the use of one of various types of SIP based messages such as an MSRP message. The MSRP message may be an MSRP SEND message. In order to transmit the MSRP message in accordance with the second transport protocol, a unidirectional SIP session should be first set up between the first functional entity and the second functional entity. That is, a message is transmitted through the unidirectional SIP session by the use of the MSRP message.

[32] The unidirectional SIP session for transmitting the MSRP message can be set up in accordance with a usual SIP session setup procedure. For example, by allowing the first functional entity to transmit the SIP message for requesting for setting up the unidirectional SIP session to the second functional entity and allowing the second functional entity to transmit a reply message to the first functional entity, the unidirectional SIP session can be set up. Here, the SIP session setup request message may be an SIP invite message (SIP/DSP message) containing an SDP offer.

[33] According to the second transport protocol, the service type information of a service requested by a user is also transmitted from the functional entity to the second functional entity. For example, the service type information can be transmitted in a state where the service type information is contained in a header portion (for example, "subject" header) or a body portion of the SIP invite message.

[34] In this way, according to the second transport protocol, since the legacy service message is transmitted using the MSRP message which is an SIP based protocol message, a message having a relatively great size can be transmitted using the second transport protocol. Therefore, the second transport protocol is suitable for transmitting a unidirectional service message having a great capacity, such as an E-mail service message or an MMS service message.

[35] According to the third transport protocol, a legacy service message can be bi- directionally transmitted between the first functional entity and the second functional entity by the use of one of various types of ISP based protocol messages such as an MSRP message. The MSRP message may be an MSSRP SEND message. In order to transmit the MSRP message in accordance with the third transport protocol, a bidirectional SIP session should be first set up between the first functional entity and the second functional entity. That is, a message can be transmitted through the bidirectional SIP session by the use of the MSRP message.

[36] The bidirectional SIP session for transmitting the MSRP message can be set up in accordance with a usual bidirectional SIP session setup procedure. For example, by allowing the first functional entity to transmit an SIP message for requesting for setting up a bidirectional SIP session to the second functional entity and allowing the second functional entity to transmit a replay message thereto to the first functional entity, the bidirectional SIP session can be set up. Here, the SIP session setup request message may be an SIP invite message (SIP/SDP message) containing an SDP offer.

[37] According to the third transport protocol, the service type information of a service requested by a user can be transmitted from the first functional entity to the second functional entity. For example, the service type information can be transmitted in a state where the service type information is contained in a header portion (for example, "subject" header) or a body portion of the SIP invite message.

[38] In this way, according to the third transport protocol, since the legacy service message is transmitted using the MSRP message, a message having a relatively great size can be bi-directionally transmitted using the third transport protocol. Therefore, the third transport protocol is suitable for transmitting messages of a bidirectional IM conversation service such as an SIMPLE-IM and an IMPS or messages of a bidirectional conversation service such as a VoIP service, a PoC service, and a Video-oIP service.

[39] A configuration of a system for transmitting various types of legacy service messages using the first transport protocol, the second transport protocol, and the third transport protocol and a message transmission procedure in the system will be described in detail.

[40] Fig. 1 is a block diagram illustrating a configuration of a system for transmitting a legacy service message in an IMS network according to an embodiment of the invention. In Fig. 1, basic configurations of entities for transmitting different types of messages between a user equipment (UE) 10 and a server system 20 through an IMS core (SIP/IMS core) using an SIP as a signaling protocol are shown.

[41] Referring to Fig. 1, the UE 10 includes a user interface (UI) 12, a client control function (CCF) 14, and one or more legacy service clients (LSC) 16. The UE 10 transmits a legacy service message using the first, second, and/or third transport protocols so as to support a converged IP messaging (CPM) service in which various services are unified through the IMS network.

[42] The UE 10 may be a fixed device or a mobile device and the kind and name thereof is not particularly limited. For example, the UE 10 may be a mobile station (MS), a laptop computer having a CPM client function built therein, or a PDA (Personal Digital Assistant). The UE 10 may be called a user terminal (UT), a mobile station (MS), a subscriber station, or a wireless device.

[43] The UE 10 accesses the IMS network by communicating with a server system 20 through the IMS core and supports various services such as the CPM service to be provided through the accessed IMS network. For example, when it is intended to transmit an SMS message using the CMP service, the UE 10 first accesses the IMS network and transmits a registration request message such as an SIP REGISTER message to the server system 20 through the IMS core to register the message in the server system 20. The SIP REGISTER message can be transmitted in a state where information on the capability of the UE 10 for the CPM service (for example, information on the types of legacy services supported by the UE 10) is contained therein along with device identification information. In this case, as described later, the in- formation on the capability of the UE 10 for the CPM service can be provided to the SCF 22 through the IMS core from the CCF 14.

[44] The UE 10 includes a user interface (UI) 12 such as a control button, a voice command, a display, and/or an acoustic device. The UI 12 interworks with the CCF 14. For example, a user request the CCF 14 for an SMS service or the like through the UI 12 and the CCF 14 notifies the user of the processing result of a query associated with a service process or the requested service through the UI 12.

[45] However, in some cases, the UI 12 may interwork with the LSC 16. That is, the user can request directly the LSC 16 for the SMS service or the like through the UI 12 and the LSC 16 can notify directly the user of the received message or the processing result of the requested service through the UI 12.

[46] The UE 10 further includes one or more legacy service clients (LSC) 16. The LSC

16 is a message processing module for generating a legacy service message or processing a received legacy service message and thus is similar to the existing LSC in function.

[47] However, according to embodiments of the invention, the function of the LSC 16 is performed by interlock with the CCF 14. That is, the LSC 16 of the transmitting UE 10 can generate a legacy service message in response to a request from the CCF 14 and can transmit the generated legacy service message to the CCF 14. The LSC 16 of the receiving UE 10 can process (for example, decode) the legacy service message transmitted from the CCF 14 and can transmit the processed message to the CCF 14 so as to notify a user of the processing result.

[48] Accordingly, the LSC 16 includes one or more LSCs, that is, an LSC-I 16a, an

LSC-2 16b, an LSC-3 16c, ..., and an LSC-n 16n (where n is an integer of 1 or greater). The LSC-I 16a, the LSC-2 16b, the LSC-3 16c, ..., and the LSC-n 16n are legacy service enable modules taking charge of corresponding legacy services. For example, the LSC-I 16a may be an SMS service client taking charge of an SMS service, the LSC-2 16b may be an MMS service client taking charge of an MMS service, the LSC-3 16c may be a SIMPLE-IM service client taking charge of a SIMPLE-IM service, and the LSC-n 16n may be a service client taking charge of a different legacy service such as an E-mail service client. Information on the types of the legacy service clients included in the LSC 16 can be provided to the server system 20 when the UE 10 accesses the IMS network for registration.

[49] The legacy service clients constituting the LSC 16 are discriminated only for the purpose of convenient explanation and can be modified in various forms logically and/ or physically. For example, the legacy service clients may be separated from each other to form independent modules or one or two or more legacy service clients may be embedded and merged to form another legacy service client module. As described later, the LSC 16 may be separated from the CCF 14 to form independent modules or may be embedded and merged in the CCF 14.

[50] The UE 10 further includes a CCF 14 for performing a function of a controller for managing communications with a server. The CCF 14 performs various functions as follows.

[51] When receiving a request for a service among various legacy services from the UI

12, the CCF 14 first determines a transport type to determine a transport protocol used to transmit a message. The CCF 14 knows the types of the legacy services in advance and determines the transport type on the basis of the service type requested from the UI 12. The transport type can be classified as follows, for example.

[52] The first transport type is restricted in the maximum size of a message and corresponds to services in which a message is transmitted uni-directionally. For example, the SMS service may correspond to the first transport type. In the first transport type, a service message requested by a user is transmitted using the above- mentioned first transport protocol.

[53] Here, the maximum size can be determined in accordance with a rule for a transmission message including the legacy service message in the first transport protocol. For example, when the legacy service message is inserted into a body portion of the SIP MESSAGE for transmission in the first transport protocol, the maximum size may be, for example, 1,300 Bytes and the maximum size of a message which can be inserted into the body portion is flexible. However, the maximum size may be properly determined within the maximum capacity range of a transmission message permitted in the rule for the transmission message.

[54] The second transport type corresponds to services in which a message having a relatively large capacity is transmitted uni-directionally. For example, the MMS service and the E-mail service may correspond to the second transport type. Accordingly, in the second transport type, the maximum size of a message may exceed, for example, 1,300 Bytes and a legacy service message is transmitted using second transport protocol B described above.

[55] The third transport type corresponds to services in which a message is transmitted bi-directionally regardless of the size of the message. For example, The SIMPLE-IM service, the IMPS service, the VoIP service, the PoC service, and the Video-oIP service may correspond to the third transport type. In the third transport type, a legacy service message is transmitted using third transport protocol C described above.

[56] An example of relations between the transport types corresponding to the types of the services requested by a user and the transport protocols used in the transport types according to an embodiment of the invention is shown in Table 2. Referring to Table 2, The CCF 14 determines that it is the "first transport type" when the service requested by a user is the SMS service, determines that it is the "second transport type" when the requested service is the MMS service or the E-mail service, and determines that it is the "third transport type" when the requested service is one of the SIMPLE-IM service, the IMPS service, the VoIP service, the PoC service, and the Video-oIP service. In the first, second, and third transport types, the legacy service messages are transmitted using the first, second, and third transport protocols, respectively.

[57] Table 2

[58] Another function of the CCF 14 is performed by interworking with the LSC 16. In this case, the CCF 14 may interwork with the separated LSC 16 or may include the merged LSC 16. That is, the LSC 16 may be embedded and physically merged into the CCF 14 or the CCF 14 and the LSC 16 may be physically separated from each other to form independent modules. The function of the CCF 14 to be performed by interworking with the LSC 16 will be described in detail now in individual cases of the transmitting UE 10 and the receiving UE 10.

[59] First, when a predetermined legacy service is requested by a user, the CCF 14 of the transmitting UE 10 acquires the legacy service message by interworking with the LSC 16. Then, a transmission message using the first, second, or third transport protocol is generated from the acquired legacy service message. For example, when a user requests for the SMS service, the CCF 14 first requests the LSC-I 16a taking charge of the SMS service among the plural LSCs 16 for generating the SMS message and acquires the generated SMS message from the LSC-I 16a. The CCF 14 generates a transmission message into which the acquired SMS message is inserted without any correction.

[60] When receiving a message using the first, second, or third transport protocol, the CCF 14 of the receiving UE 10 extracts the legacy service message from the received message and transmits the extracted legacy service message to the corresponding LSC 16. The CCF 14 receives the legacy service message processed by the corresponding the LSC 16 and notifies the user of the processed legacy service message through the UI 12. For example, the CCF 14 having received the transmission message including the SIMPLE-IM message from the SCF 22 extracts the SIMPLE-IM message from the transmission message and transmits the extracted SIMPLE-IM message to the LSC-3 16c taking charge of the SIMPLE-IM service. The CCF 14 receives the SIMPLE-IM message processed by the LSC-3 16a and notifies the user of the processed SIMPLE- IM message through the UI 12.

[61] The CCF 14 also communicates with the SCF 22 in accordance with the first, second, and/or third transport protocol. That is, the CCF 14 transmits to or receives from the SCF 22 the transmission message using the first, second, and/or third transport protocol, for example, the ISP message and/or the MSRP message.

[62] The CCF 14 manages and controls a session for communication with the SCF 22.

Specifically, the CCF 14 has an SIP session initiation function and can perform functions of generating, correcting, and ending a unidirectional or bidirectional SIP session. [0064] The CCF 14 provides capability information of the UE 10 associated with the CPM service to the server system 20. For example, when it is intended to register the UE 10 in the server system 20, the CCF 14 can provide information on the types of the LSCs 16 of the UE 10 to the server system 20 by the use of an SIP REGISTER message.

[63] Subsequently, the server system 20 according to an embodiment of the invention will be described with reference to Fig. 1. Referring to Fig. 1, the server system 20 includes a server control function (SCF) 22 and plural legacy service servers (LSS) 24.

[64] The plural LSSs 24 provided in the server system 20 serve to generate a legacy service message or to process a received legacy service message, and thus are similar to the conventional LSS in function.

[65] However, the function of the LSS 24 according to the invention is different from that of the conventional LSS in that the function can be performed by interworking with the SCF 22. That is, the LSS 24 according to the invention generates a legacy service message in response to a request from the SCF 22. The LSS 24 processes (performs processes such as confirmation of integrity of a message, charge for a message, and/or authentication) the legacy service message transmitted from the SCF 22 and requests the receive UE 10 to transmit the processed legacy service message. In this case, the LSS 24 may transmit the processed legacy service message to the SCF 22 along with the request.

[66] Accordingly, the LSS 24 include plural LSSs of an LSS- 1 24a, an LSS-2 24b, an

LSS-3 24c, ..., and an LSS-m 24m (where m is an integer of 1 or more). The LSS-I 24a, the LSS-2 24b, the LSS-3 24c, ..., and the LSS-m 24m are servers managing the services, respectively. For example, the LSS-I 24a may be an SMS service server, the LSS-2 24b may be an MMS service server, the LSS-3 24c may be an SIMPLE-IM service server, and the LSS-m 24m may be another service server such as an E-mail service server.

[67] The server system 20 has an SCF 22 for controlling a server managing the CPM service. The SCF 22 performs the following various functions.

[68] The SCF 22 knows the types of various services, similarly to the CCF 14, and determines a transport type of a legacy service message to be transmitted. The SCF 22 transmits a message using the transport protocol corresponding to the determined transport type. Since the transport types and the transport protocols corresponding thereto are similar to the first, second, and third transport types and the first, second, and third transport protocols, detailed description thereof is omitted.

[69] Another function of the SCF 22 is performed by interworking with the LSS 24. In this case, the SCF 22 may interwork with a separated LSS 24 or may include a merged LSS 24. That is, the LSS 24 may be embedded and physically merged in the SCF 22 or the SCF 22 and the LSS 24 may be physically separated from each other to form independent modules.

[70] The SCR 22 processes the received legacy service message by interworking with the LSS 24. The SCF 22 extracts the legacy service message contained in the received transmission message using the first, second, or third transport protocol and transmits the extracted legacy service message to the LSS 24. In this case, the SCF 22 can select the corresponding LSS from the plural LSSs 24 on the basis of the received service type information. The SCF 22 generates a transmission message containing the legacy service message transmitted from the LSS 24 in response to a request from the LSS 24. In this case, the transmission message can be generated using the first, second, or third transport protocol.

[71] The SCF 22 communicates with the CCF 14 in accordance with the first, second, and/or third transport protocol. That is, the SCF 22 transmits the transmission message using the first, second, and/or third transport protocol, such as an SIP MESSAGE and the MSRP message to the CCF 14, or receives the transmission message from the CCF 14.

[72] The SCF 24 manages and controls a session for communication with the CCF 14.

Specifically, the SCF 24 has the SIP session initiation function and can also perform functions of generating, correcting, and ending a unidirectional or bidirectional SIP session. The SCF 24 manages capability information of the UE 10 associated with the CPIM service.

[73]

[74] Fig. 2 is a block diagram illustrating a system configuration used to explain a method of transmitting a legacy service message between two UEs in the IMS network according to the embodiment of the invention. Referring to Fig. 2, the system includes a first UE 30, a server system 40, and a second UE 50.

[75] According to this embodiment, the first UE 30 is a device for transmitting a unidirectional service message to the second UE 50 (see the examples shown in Figs. 3 and 4) or inviting the second UE 50 to a bidirectional conversation service, and includes a first UI 32, a first CCF 34, and a first LSC 36. The first UI 32, the first CCF 34, and the first LSC 36 are examples of the UI 12, the CCF 14, and the LSC 16 described with reference to Fig. 1, respectively, and thus description thereof is omitted. The first LSC 36 includes n legacy service clients (where n is a natural number of 1 or more) and includes, for example, a first SMS service client 36a, a first MMS service client 36b, and a first SIMPLE-IM service client 36c.

[76] The server system 40 is a system for managing a unidirectional message transmission service (see the examples shown in Figs. 3 and 4) or a bidirectional conversation service (see the example shown in Fig. 5) between the first UE 30 and the second UE 50 and includes an SCF 42 and an LSS 44. The SCF 42 and the LSS 44 are examples of the SCF 22 and the LSS 24 described with reference to Fig. 1 and thus detailed description thereof is omitted. The LSS 44 includes m legacy service serves (where m is a natural number of 1 or more) such as an SMS service server 44a, an MMS service server 44b, and a SIMPLE-IM service server 44c.

[77] The second UE 50 is a device for receiving a unidirectional service message from the first UE 30 (see the examples shown in Figs. 3 and 4) or accepting an invitation to a bidirectional conversation service from the first UE 30, and includes a second UI 52, a second CCF 54, and a second LSC 56. The second UI 52, the second CCF 54, and the second LSC 56 are examples of the UI 12, the CCF 14, and the LSC 16 described with reference to Fig. 1 and thus detailed description thereof is omitted. The second LSC 56 includes n legacy service clients (where n is a natural number of 1 or more and may be equal to or different from n ) such as a second SMS service client 56a, a second MMS service client 56b, and a second SIMPLE-IM service client 56c.

[78] Fig. 3 is a flowchart illustrating a message flow of transmitting an SMS message from the first UE 30 to the second UE 50 in the system shown in Fig. 2. Although an embodiment of the invention will be described with reference to the SMS service, messages of all the services having the same characteristic as the SMS service, for example, services corresponding to the first transport type, can be transmitted using a method equal to or equivalent to an SMS message transmitting procedure to be described later.

[79] The SMS message transmitting method in the IMS network according to this embodiment is roughly divided into three procedures. In the first procedure, the first UE 30 generates a first transmission message including information indicating the SMS service and the SMS message, for example, a first SIP MESSAGE and transmits the generated message to the server system 40. In the second procedure, the server system 40 performs necessary processes on the SMS message included therein and then transmits a second transmission message including the processed SMS message and information indicating the SMS message, for example, a second SIP MESSAGE, to the second UE 50. In the final procedure, the second UE 50 processes the SMS message and then notifies a user of the reception of the SMS message.

[80]

[81] First, the first procedure (S 101 to S 105) will be described.

[82] When the SMS service is requested by a user, the first UI 32 first sends a signal requesting for the SMS service to the first CCF 34 (SlOl). The first CCF 34 determines that the SMS service corresponds to the first transport type and then requests the first LSC 36 taking charge of the SMS service, for example, the first LSC- 1 36a, to generate the SMS message (S 102). The determination of the transport type from the request for generating the SMS message is performed to determine the transport protocol used to transmit the transmission message including the SMS message on the basis of the determined transport type. Subsequently, the first LSC-I 36a having been requested to generate the SMS message generates the SMS message and sends the generated SMS message to the first CCF 34.

[83] Unlike this procedure, steps SlOl to S 103 may be performed as follows. For example, the first UI 32 directly sends a signal requesting for the SMS service to the first LSC-I 36a supporting the SMS service. The first SLC-I 36a having received the request for the SMS service may generate the SMS message and may send a request for the SMS service to the first CCF 34 along with the generated SMS message.

[84] A procedure of transmitting a message in accordance with a first transport protocol corresponding to the determined first transport type is started. First, the first CCF 34 generates a first transmission message to be transmitted to the server system 40, for example, the SCF 42 (S 104). The first transmission message may be a message using the first transport protocol. For example, the first CCF 34 may generate the first transmission message by the use of the SIP MESSAGE which is an SIP message. More particularly, the first CCF 34 can generate the first SIP MESSAGE which is the first transmission message, by inserting the service type information indicating the SMS service into a header portion (for example, "subject" header) or a body portion of the SIP MESSAGE and inserting the SMS message transmitted from the first LSC-I 36 into a body portion of the SIP MESSAGE without correction. The CCF 34 transmits the generated first SIP MESSAGE to the SCF 42 through the IMS core (S 105).

[85] [86] The second procedure (S106 to SI l 1) will be described now. The server system 40 may transmit a legacy service message or may transmit a message indicating the reception of the legacy service message, that is, a notification message, to the second UE 50.

[87] The SCF 42 having received the first SIP MESSAGE from the first CCF 34 first processes the received first SIP MESSAGE (S 106). More specifically, the SCF 42 extracts the service type information from the header portion or the body portion of the received first SIP MESSAGE and confirms that the relevant message is the SMS message. The SCF 42 extracts the SMS message from the body portion of the received first SIP MESSAGE.

[88] The SCF 42 delivers the extracted SMS message to the relevant LSS 44, for example, the LSS-I 44a which is a server taking charge of the SMS service (S 107). The delivery of the extracted SMS message to the LSS-I 44a among the plural LSSs 44 can be performed on the basis of the service type information extracted in step S106.

[89] The LSS-I 44a processes the delivered SMS message in accordance with a general message processing procedure. For example, the LSS-I 44a can perform processes such as confirmation of integrity of the delivered SMS message and/or authentication or charge independently or by interlocking with another functional entity.

[90] The LSS-I 44a having performed necessary processes on the received SMS message requests the SCF 42 to transmit the SMS message (or the SMS notification message) (S 109). In this case, the changed SMS message may be delivered to the SCF 42 when the details or format of the SMS message is changed as the process result in step S 108, or the notification message may be delivered together to the SCF 42 when the notification message indicating the reception of the SMS message is transmitted.

[91] The SCF 42 generates a second transmission message (Sl 10) to be transmitted to the second UE 50, more specifically, the second CCF 54, using the SMS message (or the SMS notification message) transmitted from the first CCF 34 or delivered from the LSS-I 44a. For example, the SCF 42 can generate a second SIP MESSAGE which is the second transmission message, by inserting the service type information into the header portion (for example, "subject" header) of the SIP MESSAGE and inserting the SMS message into the body portion of the SIP MESSAGE without correction. The SCF 42 transmits the generated second SIP MESSAGE to the second CCF 54 through the IMS core (Si l l).

[92]

[93] Finally, the second procedure (S 112 to S 116) will be described.

[94] The second CCF 54 having received the second SIP MESSAGE from the SCF 42 first processes the received message (Sl 12). More specifically, the second CCF 54 extracts the service type information from the header portion or the body portion of the received second SIP MESSAGE and confirms that the relevant message is the SMS message. The second CCF 54 extracts the SMS message (or SMS notification message) from the body portion of the received second SIP MESSAGE.

[95] The second CCF 54 delivers the extracted SMS message to the relevant LSC, for example, the second LSC-I 56a which is a client taking charge of the SMS service (Sl 13). The delivery of the extracted SMS message to the second LSC-I 56a among the plural LSCs 56 can be performed on the basis of the service type information extracted in step Sl 12.

[96] The second LSC-I 56a processes the SMS message delivered in accordance with a general message processing procedure (Sl 14). For example, in this step, the second LSC-I 56a can perform a process of decoding the delivered SMS message.

[97] The second LSC-I 56a delivers the processed SMS message to the second CCF 54

(Sl 15) and the second CCF 54 delivers the SMS message delivered from the second LSC-I 56a to the second UI 52 (Sl 16). Unlike steps Sl 15 and Sl 16, in some embodiments, the processed SMS message may be delivered directly from the second LSC-I 56a to the second UI 52.

[98] In this way, when the SMS message is transmitted from the first UE 30 to the second UE 50 in accordance with the first transport protocol, the user of the second UE 50 can check the SMS message received through the second UI 52.

[99]

[100] Fig. 4 is a flowchart illustrating a message flow of transmitting an MMS message from the first UE 30 to the second UE 50 in the system shown in Fig. 2. Although an embodiment of the invention will be described with reference to the MMS service, messages of all the services having the same characteristic as the MMS service, for example, services (such as an E-mail service) corresponding to the second transport type, can be transmitted using a method equal to or equivalent to an MMS message transmitting procedure to be described later.

[101] The MMS message transmitting method in the IMS network according to this embodiment is roughly divided into three procedures. In the first procedure, the first UE 30 generates a first transmission message including the service type information indicating the MMS service, for example, an MSRP SEND message including an SIP invite message and an MMS message, and transmits the generated message to the server system 40. In the second procedure, the server system 40 performs necessary processes on the received MMS message and then transmits a second transmission message including an MMS notification message and the service type information, for example, an SIP MESSAGE, to the second UE 50. In the final procedure, the second UE 50 processes the MMS message and then notifies a user of the second UE 50 of the reception of the MMS message.

[102]

[103] The first procedure (S201 to S208) will be described now.

[104] When a user requests for the MMS service, the first UI 32 first sends a signal requesting for the MMS service to the first CCF 34 (S201). The first CCF 34 having received the MMS service request from the first UI 32 determines that the requested service corresponds to the second transport type. Then, the first CCF 34 requests the LSC 36, for example, the first LSC-2 36b, to generate the MMS message (S202). The first LSC-2 36b having requested to generate the MMS message generates the MMS message and delivers the generated message to the first CCF 34 (S203).

[105] Unlike this embodiment, steps S201 to S203 may be performed as follows. First, the first UI 32 requests the first LSC-2 36b taking charge of the MMS service for the MMS service. The first LSC-I 36b may generate the MMS message and deliver a signal requesting for the MMS service to the first CCF 34 along with the generated MMS message.

[106] A procedure of transmitting a message in accordance with the second transport protocol corresponding to the determined second transport type is started. First, the first CCF 34 generates a session initiation request message, for example, an SIP invite message, to form an SIP session with the SCF 42 (S204). In this step, the service type information indicating the MMS service can be inserted into the header portion (for example, "subject" header) or the body portion of the SIP invite message.

[107] The first CCF 34 transmits the generated SIP invite message to the SCF 42 (S205).

In this case, an SDP offer may be contained in the SIP invite message. Subsequently, a procedure of transmitting a general message (for example, a 200 OK message) is performed between the first CCF 34 and the SCF 42 to form an SIP session between the first CCF 34 and the SCF 42. At this time, the SCF 42 extracts the service type information from the received SIP invite message. It can be seen from the extracted information that the MMS service message is contained in the transmission message received from the first CCF 34 through the SIP session.

[108] According to an aspect of this embodiment, steps S204 to S206 may be performed prior to or at the same time as S202 and S203. That is, steps S202 and S203 and steps S204 to S206 are not particularly limited in the temporal order.

[109] The first CCF 34 generates the first transmission message, for example, the MSRP

SEND message, using the MMS message received from the first LSC-2 36b (S207). In this case, the first CCF 34 can generate the second transmission message by generating the MSRP SEND message having the same size as the received MMS message and inserting the MMS message into the MSRP SEND message without correction. The first CCF 34 transmits the generated MSRP SEND message to the server system 40, more specifically, the SCF 42, through the set-up SIP session (S208).

[HO]

[111] The second procedure (S209 to S214) will be described now.

[112] The SCF 42 having received the MSRP SEND message including the MMS message from the first CCF 34 processes the received message (S209). In this step, the SCF 42 extracts the MMS message from the body portion of the received MSRP SEND message.

[113] The SCF 42 delivers the extracted MMS message to the LSS-2 44b for managing the MMS service (S210). The delivery of the extracted MMS message to the LSS-2 44b among the LSS 44 including the plural servers can be performed on the basis of the service type information extracted from the SIP invite message.

[114] The LSS-2 44b processes the delivered MMS message in accordance with a general message processing procedure (S211). For example, the LSS-2 44b can perform processes such as confirmation of integrity of the delivered MMS message and/or authentication or charge independently or by interlocking with another functional entity. The LSS-2 44b having processed the MMS message requests the SCF 42 to transmit the MMS notification message indicating the reception of the MMS message (S212). In this case, the LSS-2 44b may generate the MMS notification message and deliver the message to the SCF 42 along with the request.

[115] The SCF 42 having requested to transmit the MMS notification message from the

LSS-2 44b generates the second transmission message to be transmitted to the second CCF 54 of the second UE 50 (S213). More specifically, the SCF 42 can generate the SIP MESSAGE which is the second transmission message by inserting the service type information indicating the MMS service into the header portion (for example, "subject" header) of the second transmission message, for example, the SIP MESSAGE and inserting the MMS notification message into the body portion of the SIP MESSAGE. Then, the SCF 42 transmits the generated SIP MESSAGE to the second UE 50, more specifically, the second CCF 54, through the IMS core (S214).

[116]

[117] Finally, the third procedure (S215 to S219) will be described.

[118] The second CCF 54 having received the SIP MESSAGE including the MMS notification message and the service type information from the SCF 42 processes the received message (S215). More specifically, the second CCF 54 extracts the service type information from the header portion or the body portion of the received SIP MESSAGE and confirms that the message included in the SIP MESSAGE is the MMS message. The second CCF 54 extracts the MMS notification message from the body portion of the received SIP MESSAGE.

[119] Then, the second CCF 54 delivers the extracted MMS notification message to the second LSC-2 56b which is the LSC 56 taking charge of the MMS service (S216). In this case, the delivery of the extracted MMS notification message to the second LSC-2 56b among the second LSC 56 including plural legacy service clients can be performed on the basis of the service type information extracted in step S215.

[120] The second LSC-2 56b processes the delivered MMS notification message in accordance with a general message processing procedure (S217). For example, the second LSC-2 56b can perform a process of decoding the delivered MMS notification message.

[121] The second LSC-2 56b delivers the processes MMS notification message to the second CCF 54 (S218). The second CCF 54 notifies the second UI 52 that the MMS message has been received by delivering the MMS notification message delivered from the second LSC-2 56b to the second UI 52 (S219). Unlike steps S218 and S219, in some embodiments, the processed MMS notification message may be delivered directly from the second LSC-2 56b to the second UI 52.

[122] Thereafter, a procedure of allowing the second UE 50 to acquire the MMS message from the server system 40 is performed. This procedure can be performed using the MSRP protocol which is the SIP based protocol, that is, through the second CCF 54 and the SCF 42, similarly to the procedure of transmitting the MMS message from the first UE 30 to the server system 40.

[123]

[124] Figs. 5 and 6 are flowcharts illustrating a message flow of providing an IM conversation service between the first UE 30 and the second UE 50 in the system shown in Fig. 2. The IM conversation service is a service (such as a SIMPLE-IM service, an IMPS service, a VoIP service, a PoC service, and a Video-oIP service) corresponding to the third transport type and bidirectional message services having the same characteristic can be performed using a method equal or equivalent to the message transmission procedure in the IM conversation service.

[125] The message transmission method in the IM conversation service in the IMS network according to this embodiment is roughly divided into five procedures. In the first procedure, the first UE 30 sets up a first SIP session with the server system 40 and transmits a first transmission message including the IM invite message as a message for invitation to the IM conversation through the set-up first SIP session. The first transmission message may be a first MSRP SEND message. In the second procedure, the server system 40 performs necessary processes on the received IM invite message, sets up a second SIP session with the second UE 50, and transmits a second transmission message including the processed IM invited message, for example, a second MSRP SEND message, to the second UE 50 through the second SIP session. In the third procedure, the second UE 50 generates a third transmission message including a replay message to the received IM invite message, for example, an IM reply message, and transmits the generated third transmission message to the server system 40 through the second SIP session. The third transmission message may be, for example, a third MSRP SEND message. In the fourth procedure, the server system 40 performs necessary processes on the received IM reply message and transmits a fourth transmission message including the processed IM reply message, for example, a fourth MSRP SEND message, to the first UE 30 through the first SIP session. In the final procedure, an IM session is set up between the first UE 30 having received the IM reply message and the second UE 50 having transmitted the message.

[126]

[127] The first procedure (S301 to S308) will be described now.

[128] When a user requests for an IM conversation service, the first UI 32 sends a signal requesting for the IM conversation service to the first CCF 34 (S301). The first CCF 34 having received the request from the first UI 32 determines that the requested IM conversation service corresponds to the third transport type. Then, the first CCF 34 requests the LSC 36 taking charge of the IM conversation service, for example, the first LSC-3 36c taking charge of the SIMPLE-IM service, to generate a message for invitation to the IM conversation service (S302). The invite message may be, for example, an IM invite message. The first LSC-3 36c having requested to generate the invite message generates the IM invite message and delivers the generated message to the first CCF 34 (S303).

[129] Unlike this embodiment, steps S301 to S303 may be performed as follows, first, the first UI 32 requests directly the first LSC-3 36c, which is the LSC 36 taking charge of the SIMPLE-IM service, for the IM conversation service. The first LSC-3 36c generates the IM invite message and transmits a signal requesting for the IM conversation service to the first CCF 34 along with the generated IM invite message.

[130] A procedure of transmitting a message in accordance with the third transport protocol corresponding to the determined third transport type is started. First, the first CCF 34 generates a session initiation request message, for example, a first SIP invite message, so as to form an SIP session with the SCF 42 (S304). In this step, the service type information indicating the IM conversation service, for example, the SIMPLE-IM service, may be inserted into the header portion (for example, "subject" header) or the body portion of the first ISP invite message.

[131] The first CCF 34 transmits the generated first SIP invite message to the SCF 42

(S305). In this case, an SDP offer may be contained in the body portion of the first SIP invite message. Then, a first SIP session is set up between the first CCF 34 and the SCF 42 (S036) by performing a general message transmitting procedure between the first CCF 34 and the SCF 42. In this case, the SCF 42 can extract the service type in- formation from the received first SIP invite message.

[132] According to an aspect of this embodiment, steps S304 to S306 may be performed prior to or at the same time as steps S302 and S303. That is, steps S302 and S303 and steps S304 to S306 are not particularly limited in the temporal order thereof.

[133] The first CCF 34 generates a first MSRP SEND message as the first transmission message using the IM invite message received from the first LSC-3 36c (S307). The first CCF 34 can generate the first MSRP SEND message to be transmitted to the SCF 42 by generating the MSRP SEND message having the same size as the delivered IM invite message and inserting the IM invite message into the MSRP SEND message without correction. The first CCF 34 transmits the generated first MSRP SEND message to the server system 40, more specifically, the SCF 42, through the first SIP session (S308).

[134]

[135] The second procedure (S309 to S317) will be described now.

[136] The SCF 42 having received the first MSRP SEND message including the IM invite message from the first CCF 34 processes the received message (S309). In this step, the SCF 42 extracts the IM invite message from the body portion of the received first MSRP SEND message.

[137] The SCF 42 delivers the extracted IM invite message to the corresponding LSS, for example, the LSS-3 44c which is a server managing the SIMPLE-IM service (S310). The delivery of the extracted IM invite message to the LSS-3 44c among the LSS 44 including plural servers can be performed on the basis of the service type information extracted from the first SIP invite message.

[138] The LSS-3 44c processes the delivered IM invite message in accordance with a general message processing procedure (S311). For example, the LSS-3 44c can perform processes such as confirmation of integrity of the delivered IM invite message and/or authentication or charge independently or by interlocking with another functional entity. The LSS-3 44c having processed the IM invite message requests the SCF 42 to transmit the processed IM invite message (S312). In this case, the LSS-3 44c may deliver the processed IM invite message to the SCF 42 along with the request.

[139] The SCF 42 having requested to transmit the IM invite message by the LSS-3 44c generates a session initiation request message, for example, a second SIP invite message, so as to form an SIP session with the second CCF 54 (S313). In this step, the service type information may be inserted into header portion (for example, "subject" header) or the body portion of the second SIP invite message.

[140] The SCF 42 transmits the generated second SIP invite message to the second CCF

54 (S314). In this case, an SDP offer may be contained in the second SIP invite message. By performing a general message transmission procedure between the SCF 42 and the second CCF 54, a second SIP session is formed between the SCF 42 and the second CCF 54 (S315). At this time, the second CCF 54 can extract the service type information from the received SIP invite message.

[141] The SCF 42 generates a second transmission message, for example, a second MSRP

SEND message, using the IM invite message delivered from the LSS-3 44c (S316). The SCF 42 can generate the second MSRP SEND message by generating the MSRP SEND message having the same size as the delivered IM invite message and inserting the IM invite message into the MSRP SEND message without correction. The SCF 42 transmits the generated second MSRP SEND message to the second UE 50, more specifically, the second CCF 54, through the second SIP session (S317).

[142]

[143] The third procedure (S318 to S327) will be described now with reference to Fig. 6.

[144] The second CCF 54 having received the second MSRP SEND message including the IM invite message from the SCF 42 processes the received message (S318). In this step, the second CCF 54 extracts the IM invite message from the body portion of the received second MSRP SEND message.

[145] The second CCF 54 delivers the extracted IM invite message to the corresponding

LSC, for example, the second LSC-3 56c which is a client taking charge of the SIMPLE-IM service (S319). The delivery of the extracted IM invite message to the second LSC-3 56c the second LSC 56 including plural legacy service clients can be performed on the basis of the service type information extracted from the second SIP invite message.

[146] The second LSC-3 56c processes the delivered IM invite message in accordance with a general message processing procedure (S320). For example, the second LSC-3 56c can decode the delivered IM invite message.

[147] The second LSC-3 56c having processed the IM invite message delivers the processed IM invite message to the second CCF 54 (S321). The second CCF 54 notifies the user of the second UE 50 of the invitation to the IM conversation by delivering the delivered IM invite message to the second UI 52 (S322). Unlike steps S321 and S322, in some embodiments, the processed IM invite message may be delivered directly from the second LSC-3 56c to the second UI 52.

[148] When the user of the second UE 50 intends to accept the invitation to the IM conversation, the second UI 52 requests the second CCF 54 to transmit a message indicating the acceptance of the invitation to the conversation (S323). The second CCF 54 having received the request from the second UI 52 requests the LSC supporting the IM conversation service, for example, the second LSC-3 56c supporting the SIMPLE- IM service, to generate the IM reply message as the message indicating the acceptance of the invitation to the IM conversation service (S324) The second LSC-3 56c generates the IM reply message and delivers the generated message to the second CCF 54 (S325).

[149] Unlike this embodiment, steps S323 to S325 may be performed as follows, first, the second UI 52 requests the second LSC-3 56c, which is the LSC supporting the SIMPLE-IM service, to generate the IM reply message as the message indicating the acceptance of the invitation to the IM conversation service. The second LSC-3 56c may generate the IM reply message and request the second CCF 54 to transmit the IM reply message while transmitting the generated IM reply message thereto.

[150] The second CCF 54 generates the third transmission message, for example, the third

MSRP SEND message, using the IM reply message delivered from the second LSC-3 56c (S326). The second CCF 54 can generate the third MSRP SEND message by generating the MSRP SEND message having the same size as the delivered IM reply message and inserting the IM reply message into the body portion of the MSRP SEND message without correction. The second CCF 54 transmits the generated third MSRP SEND message to the server system 40, more specifically, the SCF 42, through the second SIP session (S327).

[151]

[152] The fourth procedure (S328 to S333) will be described now.

[153] The SCF 42 having received the third MSRP SEND message from the second CCF

54 processes the received message (S328). In this step, the SCF 42 extracts the IM reply message from the body portion of the received MSRP SEND message.

[154] The SCF 42 delivers the extracted IM reply message to the corresponding LSS, for example, the LSS-3 44c which is a server taking charge of the SIMPLE-IM service (S329). The LSS-3 44c processes the delivered IM reply message in accordance with a general message processing procedure (S330). The LSS-3 44c having processed the IM reply message requests the SCF 42 to transmit the processed IM reply message (S331). In this case, the LSS-3 44c may deliver the processed IM reply message to the SCF 42 at the same time of the request.

[155] The SCF 42 generates a fourth transmission message, for example, a fourth MSRP

SEND message, using the IM reply message delivered from the LSS-3 44c (S332). The SCF 42 can generate the fourth MSRP SEND message by generating the MSRP SEND message having the same size as the delivered IM reply message and inserting the IM reply message into the MSRP SEND message without correction. The SCF 42 transmits the generated fourth MSRP SEND message to the first UE 50, more specifically, the first CCF 34, through the first SIP session (S333).

[156]

[157] Finally, the fifth procedure (S334 to S338) will be described now.

[158] The first CCF 34 having received the fourth MSRP SEND message from the SCF 42 processes the received message (S334). In this step, the first CCF 34 extracts the IM reply message from the body portion of the received fourth MSRP SEND message.

[159] The first CCF 34 delivers the extracted IM reply message to the corresponding

LSC, for example, the first LSC-3 36c which is a client taking charge of the SIMPLE- IM service (S335). The first LSC-3 36c processes the delivered IM reply message in accordance with a generation message processing procedure (S336). For example, the first LSC-3 36c can decode the delivered IM reply message.

[160] The first LSC-3 36c having processed the IM reply message delivers the processed

IM reply message to the first CCF 34 (S337). The first CCF 34 notifies the user of the first UE 30 that the user of the second UE 50 has accepted the invitation to the IM conversation by delivering the processed IM reply message to the first UI 32 (S338). Unlike steps S337 and S338, in some embodiments, the processed IM reply may be delivered directly from the first LSC-3 36c to the first UI 32.

[161] In this way, when a message indicating the acceptance of the invitation to the IM conversation is transmitted from the second UE 50 to the first UE 30, an IM session is set up between the first UE 30 and the second UE 50, more specifically, between he first CCF 34 and the second CCF 54. The IM conversation is performed between the user of the first UE 30 and the user of the second UE 50 through the IM session. The IM conversation can be performed between the first CCF 34 and the second CCF 54 through the first SIP session and the second SIP section by the use of the SCF 42.

[162] Fig. 7 is a block diagram illustrating a system configuration used to explain a method of transmitting a legacy service message in an IMS network according to another embodiment of the invention.

[163] Referring to Fig. 7, the system includes a first UE 410 and a first server system 420.

The first UE 410 is an example of the UE 10 described with reference to Fig. 1 and includes a first UI 412, a first CCF 414, and a fist LSC 416. The first LSC 416 includes plural legacy service clients, for example, where a first LSC-I (416a) may be an SMS service client, a first LSC-2 416b may be an MMS service client, and a LSC-3 416c may be a SIMPLE-IM service client. The first server system 420 is an example of the server system 20 described with reference to Fig. 1 and includes a first SCF 422 and a first LSS 424. The first LSS 424 includes plural legacy service servers, for example, where a first LSS-I 424 may be an SMS service server, a first LSS-2 424b may be an MMS service server, and a first LSS-3 424c may be a SIMPLE-IM service server. Con figurations and functions of entities constituting the first UE 410 and the first server system 420 are similar to the configurations and functions of the UE 10 and the server system 20 and thus detailed description thereof will be omitted.

[164] The system shown in Fig. 7 includes a second legacy service server (second LSS-3

432) and a second legacy service client (second LSC-3 434). The second LSS-3 432 may be a server taking charge of an SIP protocol based service, for example, a SIMPLE-IM service, according to the related art. The second LSC-3 434 may be a client disposed in a second user equipment taking charge of the SIP protocol based service, for example, the SIMPLE-IM service, according to the related art.

[165] The system shown in Fig. 7 includes a third legacy server (third LSS-2 442) and a third legacy service client (third LSC-2 444). The third LSS-2 442 may be a server taking charge of a WSP/HTTP protocol based service, for example, an MMS service, according to the related art. The third LSC-2 444 may be a client disposed in a third user equipment taking charge of the WSP/HTTP protocol based service, for example, the MMS service, according to the related art.

[166] The system shown in Fig. 7 uses the method of transmitting a legacy service message in the IMS network according to the above-mentioned embodiment of the invention and the message transmission method according to the related art together. More specifically, the communication between the first UE 410 and the first server system 420 is performed in accordance with the method of transmitting a legacy service message according to the embodiment, for example, the first, second, and/or third protocols. However, the communication between the first LSS-3 424c which is the server taking charge of the SIMPLE-IM service in the first server system 420 and the second LSS-3 432 or the second LSC-3 434 is performed in accordance with the SIP based protocol according to the related art. The communication between the first LSS-2 424b which is the server taking charge of the MMS service in the first server system 420 and the third LSC-2 444 is performed in accordance with the WSP/HTTP based protocol through the third LSS-3 442.

[167]

[168] Fig. 8 is a block diagram illustrating a system configuration used to explain a method of transmitting a legacy service message in an IMS network according to another embodiment of the invention, where the legacy service message is transmitted between the user equipments connected to different IMS networks. Referring to Fig. 8, the system includes a fist CCF 510, a first server system 520, a second CCF 530, and a second server system 540. [0172] The first CCF 510 and the second CCF 530 are examples of the CCF 14 described with reference to Fig. 1 and first and second user equipments disposed therein, respectively, are connected to different IMS networks. The first server system 520 and the second server system 540 are also examples of the server system 20 described with reference to Fig. 1. Accordingly, The first server system 420 includes a first SCF 522 and a first LSS 524 including m legacy service servers (where m is a natural number of 1 or more). The second server system 540 includes a second SCF 542 and a second LSS 544 including m legacy service servers (where m is a natural number of 1 or more and may be equal to or different from m ). [169] The system shown in Fig. 8 uses the method of transmitting a legacy service message in the IMS network according to the above-mentioned embodiment of the invention and the message transmission method according to the related art together. More specifically, the communication between the first CCF 510 and the first SCF 522 is performed in accordance with the method of transmitting a legacy service message in the IMS network according to the embodiment of the invention, for example, the first, second, and third transport protocols. The communication between the second CCF 530 and the second SCF 542 of the second server system 540 is also performed in accordance with the method of transmitting a legacy service message in the IMS network according to the embodiment of the invention, for example, the first, second, and third transport protocols. However, the communication between the first LSS 524 of the first server system 520, for example, the first LSS-I 524a which is the server taking charge of the SMS service, and the second LSS 544 of the second server system 540, for example, the second LSS-I 544a taking charge of the SMS service is performed in accordance with the message transmission method according to the related art. Industrial Applicability

[170] According to the invention, it is possible to provide various services, which have been provided in accordance with independent transport protocols, as a unified service in the IMS network.

Claims

[1] A message transmission method of transmitting a message from a controller which interworks with one or more legacy service message processing modules, the message transmission method comprising the steps of: receiving a request for transmitting a legacy service message; and determining a message transport type on the basis of a kind of the requested legacy service message and transmitting a transmission message, which includes the requested legacy service message, to a server in accordance with a transport protocol corresponding to the determined message transport type.

[2] The message transmission method according to claim 1, further comprising a step of receiving the requested legacy service message from a specific legacy service message processing module for processing the requested legacy service message among the legacy service message processing modules.

[3] The message transmission method according to claim 2, further comprising a step of requesting the specific legacy service message processing module to generate the requested legacy service message.

[4] The message transmission method according to claim 1, wherein the controller is a client control function (CCF) and the server is a server control function (SCF).

[5] A message transmission method of transmitting a message from a controller which interworks with one or more legacy service message processing modules, the message transmission method comprising the steps of: receiving a request for transmitting a legacy service message; and transmitting a transmission message, which includes the requested legacy service message, to a server in accordance with a transport protocol of a transport type corresponding to the requested legacy service message among transport types classified based on kinds of the legacy service messages.

[6] A method of transmitting a legacy service message in an IP multimedia subsystem (IMS) network by the use of a server control function (SCF), the method comprising the steps of: receiving a first transmission message including the legacy service message; and processing the legacy service message by interworking with a legacy service server (LSS) corresponding to service type information of the legacy service message and transmitting a second transmission message including the processed legacy service message.

[7] The method according to claim 6, wherein the first transmission message and the second transmission message are both a session initiation protocol message (SIP message) and the service type information is received or transmitted in a state where the service type information is contained in the SIP message. [8] The method according to claim 7, wherein a legacy service indicated by the service type information is a short message service (SMS). [9] The method according to claim 6, further comprising a step of setting up an SIP session in cooperation with a functional entity for transmitting the first transmission message, wherein the first transmission message is received through the SIP session. [10] The method according to claim 9, wherein the first transmission message is a message (MSRP message) using a message session relay protocol (MSRP). [11] The method according to claim 9, wherein the service type information is rece ived in a state where the service type information is contained in a message for requesting for setting up the SIP session. [12] The method according to claim 11, wherein the legacy service indicated by the service type information is a multimedia message service (MMS) or an E-mail service. [13] The method according to claim 9, further comprising a step of setting up a second SIP session with a second functional entity for receiving the second transmission message, wherein the second transmission message is transmitted through the second SIP session. [14] The method according to claim 13, wherein the second transmission message is an MSRP message. [15] The method according to claim 13, wherein the service type information is transmitted in a state where the service type information is contained in a message for requesting for setting up the second SIP session. [16] The method according to claim 13, wherein the legacy service indicated by the service type information is a service of transmitting a message bi-directionally. [17] The method according to claim 16, wherein the legacy service indicated by the service type information is one of an SIMPLE-IM (SIP for Instant Message and

Presence Leverage Extensions -Instant Message) service, an IMPS (Instant

Message and Presence Service), a VoIP (Voice over IP) service, and a PoC

(Push-to-talk over Cellular) service. [18] A method of transmitting a legacy service message in an IMS network, the method comprising the steps of: setting up a first SIP session between a first client control function (CCF) and a server control function (SCF); transmitting a first transmission message, which a legacy service message acquired by interworking with a first legacy service client (LSC) supporting a service requested to the first CCF is inserted into, from the first CCF to the SCF through the first SIP session; and acquiring the legacy service message processed by interworking with a legacy service server (LSS) for processing the legacy service message and transmitting a second transmission message, which the processed legacy service message is inserted into, from the SCF to a second CCF. [19] The method according to claim 18, further comprising a step of transmitting a first session initiation request message, which includes service type information of a service requested to the first CCF, from the first CCF to the SCF, before the step of setting up the first SIP session. [20] The method according to claim 19, wherein the second transmission message is an SIP message including the service type information. [21] The method according to claim 19, further comprising a step of setting up a second SIP session between the SCF and the second CCF, before the step of transmitting the second transmission message, wherein the second transmission message is transmitted through the second SIP session. [22] The method according to claim 21, further comprising a step of transmitting a second session initiation request message, which includes the service type information, from the SCF to the second CCF, before the step of setting up the second SIP session. [23] A method of transmitting a legacy service message in an IMS network from a client control function (CCF) interworking with a plurality of legacy service clients (LSCs), the method comprising the steps of: acquiring the legacy service message by interworking with the LSC supporting a requested service among the plurality of LSCs; and adaptively transmitting a transmission message, which includes the acquired legacy service message, in accordance with a transport protocol corresponding to the type of the requested service. [24] The method according to claim 23, wherein service type information of the requested service is transmitted in a state where the service type information is contained in the transmission message. [25] The method according to claim 23, further comprising a step of transmitting a session initiation request message for requesting for setting up an SIP session before the step of transmitting the transmission message, wherein the transmission message is transmitted through the SIP session. [26] The method according to claim 25, wherein service type information of the requested service is transmitted in a state where the service type information is contained in the session initiation request message. [27] A user equipment comprising: one or more legacy service client (LSC) modules; and a client control function (CCF) for determining a transport type from a requested service and transmitting a transmission message, which includes a legacy service message acquired by interworking with the LSC module taking charge of the requested service among the LSC modules, in accordance with a transport protocol corresponding to the determined transport type. [28] The user equipment according to claim 27, wherein the transport protocol includes: a first transport protocol used to transmit an SIP message including both the legacy service message and the service type information; a second transport protocol used to set up a unidirectional SIP session and transmit an SIP based protocol message including the legacy service message through the unidirectional SIP session; and a third transport protocol used to set up a bidirectional SIP session and transmit an SIP based protocol message including the legacy service message through the bidirectional SIP session.