Abstract: A group advertisement method in a SIP (Session Initiation Protocol) based message service, and a PT client device are discussed. According to an embodiment, the method includes receiving, by a PT server, a request to send a group advertisement message for a specific PT group from a requesting PT client; determining, by the PT server, if the specific PT group is a restricted chat group or a pre-arranged group; determining, by the PT server, if the requesting PT client is allowed to send a group advertisement based on a PT group document associated with the specific PT group; and selectively transmitting, by the PT server, the group advertisement message to at least one member of the specific PT group based on results of the determining steps.

Abstract: A Push-To (PT) service of Session Initiation Protocol (SIP) based session services, and particularly, the method and system that even if a target PT client terminal is in the unregistered state to the SIP/IP core and a PT server has not received ‘PT service setting’ from the target PT client terminal yet, a particular PT client can use the PT box of the target PT client terminal.

Abstract: An apparatus and method for transferring a Rights Object (RO)for a content between devices via a server, wherein a sending device converts a first RO taken by itself to encode into a second RO, and sends an RO move request message including the second RO to the server, whereas the server converts the second RO included in the RO move request message into a third RO and transfers the third RO to a receiving device, whereby the receiving device receives the third RO from the server for installation, wherein the sending device deletes or modifies the first RO at an appropriate time point.

Abstract: A broadcast/multicast (BCAST) service, specifically, a BCAST service system for transmitting broadcast contents to terminals when a network load is small and a contents transmission method using the same are disclosed. When contents are broadcast by using a distribution window (DM) and a presentation window (PW), the terminals feed back a message indicating reception confirmation of the contents to the network, such that the contents reception success rate between the terminals and the network can be improved.

Abstract: A method of digital rights management for a broadcast-multicast service, the method comprising receiving a request from a terminal to join a service domain having a common group key; transmitting encryption of one or more service encryption keys using the common group key to the terminal that requested to join; and allowing the terminal to share the same contents and the same services with one or more other devices within the service domain.

Abstract: A method for restricting a push-to (PT) service restricts a PT service with reference to network information. A PT client inviting to a PT session restricts an invited PT client by setting a network dependent outgoing session barring flag as ‘ON’. A PT client invited to the PT session restricts the inviting PT client by setting a network dependent incoming session barring flag as ‘ON’. The inviting PT client or the invited PT client can be selectively restricted by using information on operation conditions under which the flags are operated.

Abstract: A method for providing a push-to (PT) service employing an invitation reservation mechanism is disclosed in which an invitation reservation function is set in a PT server so that, without an instruction of a PT client, the PT server can invite other PT clients who are available for session establishment. A method for reserving a PT service includes setting an invitation reservation function in a transmitting side PT server; requesting and receiving by the transmitting side PT server state information of PT clients who are targets for joining a session when operation conditions of the invitation reservation function are met; and transmitting by the transmitting side PT server an invite signal to the PT clients when the PT clients are in a state available for establishment of a session.

Abstract: In a broadcast/multicast service based on user location information, when a terminal sets contents desired to be received in a specific area, a broadcast/multicast server checks current location information of the terminal transmitted from a location server or from the corresponding terminal, selects contents provided in the corresponding area, and transmits it to the terminal. Thus, a waste of a communication channel can be prevented, and since a user can selectively receive contents or information according to his/her location, user's satisfaction and convenience can be enhanced.

Abstract: A system for interworking messages of a mobile communications terminal employs a method of receiving by a first messaging service server a multimedia message sent by a first user client of a first messaging service, processing the multimedia message at the first messaging service server and at a second messaging service server, and providing by the second messaging service server the processed multimedia message to a second user client of a second messaging service. The message includes a parameter that indicates the originating messaging service type or the recipient messaging service type as a field or an indicator in the header portion or body portion of the message.