Abstract:
In order to solve the problem in the prior art that presence information can not be correctly displayed according to the actual source of presence information in case of such as call forward, the present invention provides a method and device in a network server for controlling presence information of a first user equipment. The method comprises: receiving instruction information, wherein the instruction information is used for indicating to display presence information of the first user equipment as presence information of a second user equipment; obtaining presence information of the second user equipment; providing presence information of the second user equipment to an observer subscribing to presence information of the first user equipment, so that presence information of the first user equipment, to which the observer subscribes, is displayed as presence information of the second user equipment. Using the solution of the present invention, the relocation for presence information of a user equipment can be achieved, which enables the user to show his presence information to other users subscribing to his presence information more flexibly.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to communication network, especially to a method and apparatus for processing presence service in an IMS (IP Multimedia Subsystem) in a communication network. 
       BACKGROUND OF THE INVENTION 
       [0002]    Currently, the popularization of the interne service has changed people&#39;s communication custom to a great extent. Besides the traditional voice communication, the instant messaging service is becoming more and more popular in a plurality of users due to its high efficiency, convenience, good privacy etc. In order to meet more and more demands of people for the instant messaging service, the mobile network and terminal technique also need to be improved and extended accordingly. As a result, Presence technique occurs. 
         [0003]    Presence service is also called presence service, online state service, etc, and plays a very important role in instant communication. Depending on Presence technique, an instant messaging service user may set the user presence information as one of a plurality of states such as “in calling”, “during a meeting”, etc, and at the same time set in which state the user has which communication abilities and wants to use which communication mode, and the user may also subscribe to presence information of others so that the calling party knows whether the called party may be connected before calling. When the user is busy, he may set his presence information as offline or in busy, thereby preventing the interference caused by unnecessary calling. Therefore, presence information is convenient for both the calling party and the called party to select the most suitable communication mode in a certain occasion so as to improve the communication efficiency and communication quality. 
         [0004]    For example, when the mobile phone of a user is shutdown due to lack of power, the user may forward all calls of his mobile phone to his fixed line. However, since presence information of the mobile phone of the user still shows the mobile phone is offline, that is, what is shown on the subscriber subscribing to the presence information of the mobile phone is that the state of the mobile phone is still offline, therefore, it is quite possible for the other subscriber wishing to contact the user not to call the mobile phone of the user due to the offline state of the mobile phone. Therefore, it is quite possible that the user still can not get the call from his subscriber such as a client since the others may not initiate a call request to an offline user equipment though the user activates the function of forwarding the mobile phone call to the fixed line. 
       SUMMARY OF THE INVENTION 
       [0005]    As there is aforesaid problem in the prior art, the present invention proposes a method and device for setting to show the information source. 
         [0006]    According to the first aspect of the present invention, there is provided a method, in a network server, of controlling presence information of a first user equipment, wherein the method comprises the following steps of: receiving instruction information, wherein the instruction information is used for indicating to display presence information of the first user equipment as presence information of a second user equipment; obtaining presence information of the second user equipment; providing presence information of the second user equipment to an observer subscribing to presence information of the first user equipment, so that presence information of the first user equipment, to which the observer subscribes, is displayed as presence information of the second user equipment. 
         [0007]    According to the second aspect of the present invention, there is provided a control device in a network server for controlling presence information of a first user equipment, wherein the device comprises: a receiving means, for receiving instruction information, wherein the instruction information is used for indicating to display presence information of the first user equipment as presence information of a second user equipment; an obtaining means, for obtaining presence information of the second user equipment; a providing means, for providing presence information of the second user equipment to an observer subscribing to presence information of the first user equipment, so that presence information of the first user equipment, to which the observer subscribes, is displayed as presence information of the second user equipment. 
         [0008]    Using the solution of the present invention, the relocation for presence information of a user equipment can be achieved, which enables the user to show his presence information to other users subscribing to his presence information more flexibly. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objects and advantages of the present invention will become apparent. 
           [0010]      FIG. 1  is a schematic diagram of a network topology structure, according to a detailed embodiment of the present invention; 
           [0011]      FIG. 2  shows a flowchart of a method, according to a detailed embodiment of the present invention; 
           [0012]      FIG. 3  shows a logical representation of a presence information proxy server  1 , according to a detailed embodiment of the present invention; 
           [0013]      FIG. 4  shows a flowchart of a system method, according, to a detailed embodiment of the present invention; 
           [0014]      FIG. 5  shows a block diagram of a device for controlling presence information of a first user equipment  2   a  in the presence information proxy server  1 , according to a detailed embodiment of the present invention; 
       
    
    
       [0015]    In drawings, same or similar reference signs refer to the same or similar step feature or device/module. 
       DETAILED DESCRIPTION OF EMBODIMENTS 
       [0016]    In the followings, each of the non-limiting embodiments of the present invention is described in detail with reference to the drawings. 
         [0017]      FIG. 1  is a schematic diagram of a network topology structure, according to a detailed embodiment of the present invention.  FIG. 1  shows an application of the present invention in IMS. Certainly, those skilled in the art should understand that the present invention is not only limited to IMS network and suitable for any network which may support present information. Each of network function entities related to the present invention is shown in  FIG. 1 . The following function entities: a P-CSCF (Proxy-Call Session Control Function), an I-CSCF (Interrogating-Call Session Control Function), a S-CSCF (Serving Call Session Control Function), an HSS (Home Subscriber Server), an application server, a PS (Presence Server) and a presence information proxy server  1  are shown in the IMS  3  denoted with cloud diagram in  FIG. 1 . Wherein the presence information proxy server  1  is a newly added function entity for implementation of the present invention. 
         [0018]    Wherein the P-CSCF is the first contact node when a UE (User Equipment) obtains an IMS service. The UE gets the address of the P-CSCF through a “local CSCF discovery procedure”. The function of the P-CSCF is similar to a proxy server and the P-CSCF processes or forwards the received request and service. 
         [0019]    The I-CSCF may act as a connection point of all users of network, or may also be used as a SAP (Service Access Point) of roaming users within the current network service zone. 
         [0020]    The S-CSCF performs session controlling function and may maintain session state information according to the requirement of the network operator. 
         [0021]    The HSS is a database of users and service information, which supports CS domain, PS domain and IMS subsystem. 
         [0022]      FIG. 1  further shows: the S-CSCF and the application server exchange messages through an ISC interface based on SIP (Session Initiation Protocol); the S-CSCF and the HSS communicate through a Cs interface based on Diameter Protocol; the HSS and the application server exchange information through a Sh interface based on Diameter Protocol. 
         [0023]    For the detailed functions of P-CSCF, I-CSCF and S-CSCF, there are related descriptions in the existing protocols. Furthermore, those skilled in the art may refer to the related reference books, for example &lt;&lt;3G core network technique&gt;&gt; (ISBN 7-118-04056-8) published by National Defense Industry Press or &lt;&lt;concept and service of IP multimedia in mobile field&gt;&gt; (ISBN 7-111-15835-0/TN-404) published by China Machine Press, etc. Therefore, it is not repeated again here. 
         [0024]    A plurality of UEs  2   a ,  2   b  and  2   c  are shown in  FIG. 1 . Wherein  2   a  is a mobile phone and  2   b  is a fixed line phone such as a videophone, and  2   c  is a notebook computer. Certainly, the UEs may also include PDA (Personal Data Assistant), etc. each of UEs may be connected into the IMS network through the presence information proxy server  1 . 
         [0025]    The presence information proxy server  1  shown in  FIG. 1  is an instance of “network server”, and it is only a functional entity. The presence information proxy server  1  may be separate network servers, or may be integrated with other servers, for example, the presence information proxy server  1  is integrated in the PS or other network servers or application servers. 
         [0026]      FIG. 2  shows a flowchart of a method for controlling presence information of the first UE  2   a  in the presence information proxy server  1 , according to a detailed embodiment of the present invention. In the followings, a detailed embodiment of the method of the present invention is described in detail referring to  FIG. 2  and in combination with  FIG. 1   
         [0027]    In the embodiment, taking presence information of the UE  2   b  as the source of presence information of the UE  2   a  is taken as an example to illustrate. 
         [0028]    As shown in  FIG. 2 , in the step S 10 , the presence information proxy server  1  receives signaling information, the signaling information comprises provision of users for indicating to display presence information of the first UE  2   a  as presence information of a second UE  2   b , therefore, necessarily, ID of UE of the first UE  2   a  and ID of UE of the second UE  2   b  are included in the signaling information. Those skilled in the art may understand that any user having permission may set the source of presence information of the first UE  2   a  as the second UE  2   b  and is not limited to the user of the first UE or the second UE. Furthermore, it is unnecessary that the first UE  2   a  and the second UE  2   b  belong to the same user. Preferably, the first UE  2   a  and the second UE  2   b  belong to the same user. The user may select the source of presence information of the first UE  2   a  which he wishes to set, by logging on the page via which the presence information proxy server  1  may be connected to, or by manual input or by a drop-down menu. In the embodiment, the user sets the source of presence information of the first UE  2   a  as the second UE  2   b . Certainly, the user also may select other ways to perform the aforesaid presence information source setting, for example, the user may set the source of presence information of the first UE  2   a  as the second UE  2   b  by short-message interaction, or voice menu, or button input. Those skilled in the art may understand that the detailed obtaining ways, in which the presence information proxy server  1  obtains the instruction information for indicating the actual source of presence information of the first UE  2   a , are not limited to the aforesaid examples which are all non-limiting. 
         [0029]    In the step S 11 , the presence information proxy server  1  obtains presence information of the second UE  2   b . For example, the second UE  2   b  periodically publishes to the PS each of information of the second UE  2   b  through publish request (publish request information, called publish message below for the convenience of description), wherein each of information of the second UE  2   b  comprises ID of the second UE  2   b , TTL (Time To Live) of the publish message, and presence information of the second UE  2   b , for example, the current state of the second UE  2   b , whether it is online or offline, during a meeting, in calling, etc. In addition, presence information may also comprise personalized information representing the user of the second UE  2   b , for example, the current mood which is denoted with a smiling face, etc. The publish message also comprises other information, which is defined in the existing protocol and has less correlation with the present invention, and thus it is not repeated again here. 
         [0030]    After the presence information proxy server  1  obtains not only instruction information for indicating to set the source of presence information of the first UE  2   a  as the second UE  2   b  but also presence information of the second UE  2   b , the method goes into the step S 12 , the presence information proxy server  1  provides presence information of the second UE  2   b  to observers subscribing to presence information of the first UE  2   a , so that presence information of the first UE  2   a , to which the observer subscribes, is displayed as presence information of the second UE  2   b.    
         [0031]    The observer is the subscriber subscribing to presence information of the first UE  2   a . The observer registers to the user of the first UE  2   a , and is authenticated by the user of the first UE  2   a  to be able to obtain presence information of the first UE  2   a . That is, when the user updates presence information of the first UE  2   a  (including newly build, add, modify, delete), the observer may synchronously or asynchronously display the updated presence information of the first UE  2   a . For example, in an example of instant messaging, for example, in a MSN instant messaging based on SIP protocol, state information comprises online, busy, be right back, depart, in calling, eating out, appear offline, etc, that is, presence information of the present invention. After the user modifies state information of the first UE  2   a , the modified state information of the first UE  2   a  is displayed in the contact list of friends (that is, the observer in the present invention) of the user. 
         [0032]    The presence information proxy server  1  needs not to know presence information of the first UE  2   a , since in instruction information it is indicated that the first UE  2   b  is taken as the source of presence information of the first UE  2   a , the presence information proxy server  1  only needs to know presence information of the second UE  2   b . The presence information proxy server  1  provides to the observer of the first UE  2   a  presence information of the first UE  2   b  as presence information of the first UE  2   a  according to ID of the first UE  2   a  in the instruction information and presence information of the second UE  2   b , and the observer of the first UE  2   a  will not know that the obtained presence information of the first UE  2   a  is actually from the second UE  2   b , that is, modification of the source of presence information of the first UE  2   a  is transparent to the observer of the first UE  2   a.    
         [0033]    In a varied embodiment, before obtaining the publish message of the first UE  2   b , the presence information proxy server  1  has already obtained the publish message of the first UE  2   a . The publish message of the first UE  2   a  comprises ID of the first UE, TTL (Time To Live) of the publish message, and presence information of the first UE  2   a . Furthermore, the publish message also comprises other information, which is defined in the related protocol, and thus it is not repeated again. Furthermore, the presence information proxy server  1  also receives instruction message for indicating to display presence information of the first UE  2   a  as presence information of the second UE  2   b . Then, the presence information proxy server  1  does not send the publish message of the first UE  2   a  immediately but buffers the publish message of the first UE  2   a . To be specific, in the step S 12 , the presence information proxy server  1  may process the publish message from the first UE  2   a  by any one of at least the following two ways: 
         [0034]    I) the presence information proxy server  1  buffers the whole publish message of the first UE  2   a  in database, in which the presence information of the first UE  2   a  is included; after receiving the presence information of the second UE  2   b , the presence information proxy server  1  only replaces the presence information in the publish message of the first UE  2   a  with the presence information of the second UE  2   b  and keeps other information in the first UE  2   a  unchanged, and provides to the PS the modified publish message of the first UE  2   a . Then the PS provides to the observer of the first UE  2   a  the modified publish message of the first UE  2   a  according to the existing flow, for example calling flow. Since the presence information proxy server  1  only modifies presence information in the publish message and does not modify other information, the observer, receiving the modified presence information of the first UE  2   a , will not know that the actual source of the presence information has changed. 
         [0035]    II) the presence information proxy server  1  buffers partial information of publish message of the first UE  2   a  in database, that is, all other information except for the presence information of the first UE  2   a , and the presence information of the first UE  2   a  is discarded; after receiving the presence information of the second UE  2   b , the presence information proxy server  1  takes the presence information of the second UE  2   b  as the presence information of the first UE  2   a  and keeps other information of the first UE  2   a  unchanged, and provides to the PS the modified publish message of the first UE  2   a . The PS provides to the observer of the first UE  2   a  the modified publish message of the first UE  2   a  according to the existing flow, for example calling flow. Since the presence information proxy server  1  only modifies presence information in the publish message and does not modify other information, the observer, receiving the modified presence information of the first UE  2   a , will not know that the actual source of the presence information has changed. 
         [0036]    In aforesaid embodiment, the step S 10  is firstly described, that is, the presence information proxy server  1  obtains instruction information, and then obtains the presence information of the second UE  2   b  in the step S 11 . It should be understood that there is not obvious sequence relationship between the step S 10  and S 11 . In a varied embodiment, the method may also perform the step S 11  first, that is, obtaining the presence information of the second UE  2   b , and then obtains instruction information, as long as both the steps S 10  and S 11  occur prior to the step S 12 . 
         [0037]    In aforesaid embodiment, the user may set the source of the presence information of the first UE  2   a  as the second UE  2   b . In a varied embodiment, the user may set the source of the presence information of the first UE  2   a  as the second UE  2   b , moreover, the user or other users also may set the source of the presence information of the second UE  2   b  as the third UE, for example the UE  2   c  shown in  FIG. 1 . The actual source of the presence information of the first UE  2   a , obtained by the observer of the first UE  2   a , is the UE  2   c . In the varied embodiment, an obtaining means obtains the presence information of the third UE  2   c  and takes the presence information of the third UE  2   c  as the presence information of the second UE, and a providing means  102  provides the presence information of the third UE  2   c  to the observer of the presence information of the first UE  2   a , that is, the third UE  2   c  is taken as the actual source of the presence information of the first UE  2   a.    
         [0038]    In a varied embodiment, the operator may bind call forward service with presence information forward service. That is, when the call forward, which the first UE  2   a  forwards to the second UE  2   b , is activated, the application service, which transfers the source of the presence information of the first UE  2   a  to the second UE  2   b , is activated simultaneously. 
         [0039]    To be specific, in the network server, for example, in the presence information proxy server  1 , the operator may set: when the presence information proxy server  1  obtains instruction information activating the first UE  2   a  to forward call to the second UE  2   b , for example, the user sets to forward call to the second UE  2   b  through the option of call forward of menu in the first UE  2   a  (for example mobile phone), which may be forwarding all voice calling unconditionally, or forwarding data communication, or performing call forward in a specific scenario, for example, when the local line is busy, when the phone is not answered, when no network or the phone is power off, or when the phone can not be connected, etc. Certainly, the operator may set to activate corresponding presence information forwarding application only when unconditional forwarding, or, as long as call forward is performed, whether unconditional call forward or conditional call forward, corresponding presence information forwarding applications are activated. For example, when the presence information proxy server  1  receives the request for activating call forward to the second UE  2   b  from the first UE  2   a , while modifying the attribute of call in database, the presence information proxy server  1  records and modifies the source of the presence information of the first UE  2   a  to the second UE  2   b  accordingly. 
         [0040]    In the followings, the logical representation of the present invention is described in detail referring to  FIG. 3 .  FIG. 3  shows a logical representation of a presence information proxy server  1 , according to a detailed embodiment of the present invention. 
         [0041]    As shown in  FIG. 3 , the presence information proxy server  1  has a network interface. The presence information proxy server  1  has at least two network interfaces, in which one network interface is a state information interface for receiving presence information from users and providing it to a PS in the IMS network, and the interface supports protocols provided by TS24.141. The other network interface is the interface provided by the operator for receiving instruction information (that is, configuration information) from UEs. 
         [0042]    Maintenance logic: is used for writing configuration information of users, that is, instruction information of users to the database. 
         [0043]    Provision database: is used for saving configuration information of users, that is, instruction information of users. 
         [0044]    Service logic: is used for providing to the PS the right presence information. 
         [0045]    The embodiment shown in  FIG. 2  describes the embodiment of the present invention from the aspect of the presence information proxy server  1 . In the followings, a flowchart of a system method, according to a detailed embodiment of the present invention is described referring to  FIG. 4 . The first UE  2   a , the second UE  2   b , the presence information proxy server  1 , the P-CSCF, the S-CSCF and the PS of  FIG. 4  have been shown in  FIG. 1  and described hereinbefore, therefore, it is not repeated herein again.  FIG. 4  shows the detailed flow of the process of interaction and answer for updating presence information among each of network entities, wherein in configuration information, the user sets the source of presence information of the first UE  1  as the second UE  2 . 
         [0046]    As shown in  FIG. 4 , in the step S 400 , The first UE  2   a  sends publish request in which ID of the first UE  2   a , presence information, TTL of the publish request, and security verify of publish message, etc may be included. 
         [0047]    Then, in the step S 401 , according to configuration information of users, the presence information proxy server  1  performs service control logic for presence information from the first UE  2   a , for example, discarding original presence information in the publish request and reserving other information in the publish request, for example, reserving ID of the first UE  2   a , TTL of the publish request, security verify, etc. 
         [0048]    Then, in the step S 402 , the presence information proxy server  1  sends to the first UE  2   a  a response message, that is,  200  (OK). According to the related specification of Presence,  200  (OK) is the response to the step S 400 , which indicates that the server has received the publish request message from the first UE  2   a . Because discarding presence information of the first UE  2   a  is the process in the presence information proxy server  1  and does not involve the interaction between the presence information proxy server  1  and the first UE  2   a , it is not necessary to change the interface between the presence information proxy server  1  and the first UE  2   a , that is, the presence information proxy server  1  still sends the standard response  200  OK to the first UE  2   a.    
         [0049]    Then, in the step S 403 , the second UE  2   b  sends a publish request message in which ID of the second UE  2   b , presence information, TTL of the publish request, and security verify of publish message, etc may be included. 
         [0050]    Then, in the step S 404 , the service control logic of the presence information proxy server  1  comprises updating the publish message for the first UE  2   a  based on the presence information of the second UE  2   b , and only presence information in the updated publish message of the first UE  2   a  is from the second UE  2   b . Unless other information in the publish request message needs to be changed in configuration information of the user, other information keeps unchanged, that is, other information is from the original publish message of the first UE  2   a . Therefore, after receiving presence information of the first UE  2   a , the observer of the first UE  2   a  will not know that presence information of the first UE  2   a  is actually from the second UE  2   b.    
         [0051]    Then, in steps S 405 , S 406  and S 407 , the presence information proxy server  1  sends to the PS the updated publish request message of the first UE  2   a  and publish request message of the second UE  2   b  via forwarding of the P-CSCF and S-CSCF. Wherein publish request message of the second UE  2   b  is not changed, and publish message of the first UE  2   a  is updated by the presence information proxy server  1  according to presence information of the second UE  2   b.    
         [0052]    In the step S 408 , a proxy server sends  200  (OK) message to the second UE  2   b , and the  200  (OK) is a response message and means that the proxy server has received the publish request from the second UE  2   b . It is notable that the PS does not need to send the  200  (OK) response message to the first UE  2   a  now because the presence information proxy server  1  has sent  200  (OK) message to the first UE  2   a  in the step S 402 . Then, in steps S 409 -S 411 , the S-CSCF, the P-CSCF and the presence information proxy server  1  respectively forward the  200  (OK) message from the PS. 
         [0053]    When PUBLISH is finished, the PS informs the observer of the updated presence information according to the current flow, now the actual source of presence information of the first UE  2   a , obtained by the observer of the first UE  2   a , is the second UE  2   b.    
         [0054]      FIG. 5  shows a block diagram of a device for controlling presence information of a first UE  2   a  in the presence information proxy server  1 , according to a detailed embodiment of the present invention. In the followings, detailed embodiments of the device of the present invention are described in detail referring to  FIG. 5  and in combination with  FIG. 1  and  FIG. 2 . 
         [0055]    A control device  10  shown in  FIG. 5  is located in the presence information proxy server  1  shown in  FIG. 1 . The control device  10  comprises a receiving means  100 , an obtaining means  101  and a providing means  102 . 
         [0056]    In the embodiment, taking presence information of the UE  2   b  as the source of presence information of the UE  2   a  is taken as an example to illustrate. 
         [0057]    As shown in  FIG. 5 , the receiving means receives signaling information, the signaling information comprises provision of users for indicating to display presence information of the first UE  2   a  as presence information of a second UE  2   b , therefore, necessarily, ID of UE of the first UE  2   a  and ID of UE of the second UE  2   b  are included in the signaling information. Those skilled in the art may understand that any user having permission may set the source of presence information of the first UE  2   a  as the second UE  2   b  and is not limited to the user of the first UE or the second UE. Furthermore, it is unnecessary that the first UE  2   a  and the second UE  2   b  belong to the same user. Preferably, the first UE  2   a  and the second UE  2   b  belong to the same user. The user may select the source of presence information of the first UE  2   a  which he wishes to set, by logging the page via which the presence information proxy server  1  may be connected to, by manual input or by a drop-down menu. In the embodiment, the user sets the source of presence information of the first UE  2   a  as the second UE  2   b . Certainly, the user also may select other ways to perform the aforesaid presence information source setting, for example, the user may set the source of presence information of the first UE  2   a  as the second UE  2   b  by short-message interaction, or voice menu, or button input. Those skilled in the art may understand that the detailed obtaining ways, in which the presence information proxy server  1  obtains the instruction information for indicating the actual source of presence information of the first UE  2   a , are not limited to the aforesaid examples which are all non-limiting. 
         [0058]    After then, the obtaining means obtains presence information of the second UE  2   b . For example, the second UE  2   b  periodically publishes to the PS each of information of the second UE  2   b  through publish request (publish request information, called publish message below for the convenience of description), wherein each of information of the second UE  2   b  comprises ID of the second UE  2   b , TTL (Time To Live) of the publish message, and presence information of the second UE  2   b , for example, the current state of the second UE  2   b , whether it is online or offline, during a meeting, in calling, etc. In addition, presence information may also comprise personalized information representing the user of the second UE  2   b , for example, the current mood which is denoted with a smiling face, etc. The publish message also comprises other information, which is defined in the existing protocol and has less correlation with the present invention, and thus it is not repeated again here. 
         [0059]    After the presence information proxy server  1  obtains not only instruction information for indicating to set the source of presence information of the first UE  2   a  as the second UE  2   b  but also presence information of the second UE  2   b , the providing means  102  provides presence information of the second UE  2   b  to observers subscribing to presence information of the first UE  2   a , so that presence information of the first UE  2   a , to which the observer subscribes, is displayed as presence information of the second UE  2   b.    
         [0060]    The observer is the subscriber subscribing to presence information of the first UE  2   a , the observer registers to the user of the first UE  2   a , and is authenticated by the user of the first UE  2   a  to be able to obtain presence information of the first UE  2   a . That is, when the user updates presence information of the first UE  2   a  (including newly build, add, modify, delete), the observer may synchronously or asynchronously displays the updated presence information of the first UE  2   a . For example, in an example of instant messaging, for example, in a MSN instant messaging based on SIP protocol, state information comprises online, busy, be right back, depart, in calling, eating out, appear offline, etc, that is, presence information of the present invention. After the user modifies state information of the first UE  2   a , the modified state information of the first UE  2   a  is displayed in the contact list of friends (that is, the observer in the present invention) of the user. 
         [0061]    The presence information proxy server  1  need not to know presence information of the first UE  2   a , since in instruction information it is indicated that the first UE  2   b  is taken as the source of presence information of the first UE  2   a , the presence information proxy server  1  only needs to know presence information of the second UE  2   b . The providing means  102  provides to the observer of the first UE  2   a  presence information of the first UE  2   b  as presence information of the first UE  2   a  according to ID of the first UE  2   a  in the instruction information and presence information of the second UE  2   b , and the observer of the first UE  2   a  will not know that the obtained presence information of the first UE  2   a  is actually from the second UE  2   b , that is, modification of the source of presence information of the first UE  2   a  is transparent to the observer of the first UE  2   a.    
         [0062]    In a varied embodiment, before obtaining the publish message of the first UE  2   b , the obtaining means  101  has already obtained the publish message of the first UE  2   a . The publish message of the first UE  2   a  comprises ID of the first UE, TTL (Time To Live) of the publish message, and presence information of the first UE  2   a . Furthermore, the publish message also comprises other information, which is defined in the related protocol, and thus it is not repeated again. Furthermore, the presence information proxy server  1  also receives instruction information for indicating to display presence information of the first UE  2   a  as presence information of the second UE  2   b . Then, the providing means  102  does not send the publish message of the first UE  2   a  immediately, but the control device  10  also comprises a storing means (not shown in  FIG. 5 ), the storing means buffers the publish message of the first UE  2   a . To be specific, an updating means (not shown in  FIG. 5 ) may process the publish message from the first UE  2   a  by any one of at least the following two ways: 
         [0063]    I) the updating means buffers the whole publish message of the first UE  2   a  in database, in which the presence information of the first UE  2   a  is included herein; after the obtaining means receives the presence information of the second UE  2   b , the updating means only replaces the presence information in the publish message of the first UE  2   a  with the presence information of the second UE  2   b  and keeps other information in the first UE  2   a  unchanged, and then the providing means  102  provides to the PS the modified publish message of the first UE  2   a . Then the PS provides to the observer of the first UE  2   a  the modified publish message of the first UE  2   a  according to the existing flow, for example calling flow. Since the updating means only modifies presence information in the publish message and does not modify other information, the observer, receiving the modified presence information of the first UE  2   a , will not know that the actual source of the presence information has changed. 
         [0064]    II) the updating means buffers partial information of publish message of the first UE  2   a  in database, that is, all other information except for the presence information of the first UE  2   a , and the presence information of the first UE  2   a  is discarded; after the obtaining means receives the presence information of the second UE  2   b , the updating means takes the presence information of the second UE  2   b  as the presence information of the first UE  2   a  and keeps other information in the first UE  2   a  unchanged, and then the providing means  102  provides to the PS the modified publish message of the first UE  2   a . The PS provides to the observer of the first UE  2   a  the modified publish message of the first UE  2   a  according to the existing flow, for example calling flow. Since the presence information proxy server  1  only modifies presence information in the publish message and does not modify other information, the observer, receiving the modified presence information of the first UE  2   a , will not know that the actual source of the presence information has changed. 
         [0065]    In aforesaid embodiment, there is not obvious sequence relationship between the operation that the receiving means  100  obtains instruction information and the operation that the obtaining means obtains the presence information of the second UE  2   b . In a varied embodiment, firstly, the obtaining means obtains the presence information of the second UE  2   b , and then the receiving means obtains instruction information, only after the receiving means  100  and the obtaining means respectively obtain corresponding information, the providing means can perform corresponding operation. 
         [0066]    In aforesaid embodiment, the user may set the source of the presence information of the first UE  2   a  as the second UE  2   b . In a varied embodiment, the user may set the source of the presence information of the first UE  2   a  as the second UE  2   b , moreover, the user or other users also may set the source of the presence information of the second UE  2   b  as the third UE, for example the UE  2   c  shown in  FIG. 1 . The actual source of the presence information of the first UE  2   a , obtained by the observer of the first UE  2   a , is the UE  2   c . In the varied embodiment, an obtaining means obtains the presence information of the third UE  2   c  and takes the presence information of the third UE  2   c  as the presence information of the second UE, and a providing means  102  provides the presence information of the third UE  2   c  to the observer of the presence information of the first UE  2   a , that is, the third UE  2   c  is taken as the actual source of the presence information of the first UE  2   a.    
         [0067]    In a varied embodiment, the operator may bind call forward service with presence information forward service. That is, when the call forward, which the first UE  2   a  forwards to the second UE  2   b , is activated, the application service, which transfers the source of the presence information of the first UE  2   a  to the second UE  2   b , is activated simultaneously. 
         [0068]    To be specific, in the network server, for example, in the presence information proxy server  1 , the operator may set: when the presence information proxy server  1  obtains instruction information activating the first UE  2   a  to forward call to the second UE  2   b , for example, the user sets to forward call to the second UE  2   b  through the option of call forward of menu in the first UE  2   a  (for example mobile phone), which may be forwarding all voice calling unconditionally, or forwarding data communication, or performing call forward in a specific scenario, for example, when the local line is busy, when the phone is not answered, when no network or the phone is power off, or when the phone can not be connected, etc. Certainly, the operator may set to activate corresponding presence information forwarding application only when unconditional forwarding, or, as long as call forward is performed, whether unconditional call forward or also conditional call forward, corresponding presence information forwarding applications are activated. For example, when the presence information proxy server  1  receives the request for activating call forward to the second UE  2   b  from the first UE  2   a , while modifying the attribute of call in database, the presence information proxy server  1  records and modifies the source of the presence information of the first UE  2   a  to the second UE  2   b  accordingly. 
         [0069]    It can be understood, in the aforesaid embodiments of device parts, the receiving means is used for obtaining configuration information of users, and the obtaining means is used for obtaining presence information of users, in the present invention, two means are taken to be described. In actual application, the receiving means and the obtaining means may be reused. 
         [0070]    Embodiments of the present invention is described hereinafter, but the present invention is not limited to the specific system, apparatus and detailed protocols, those skilled in the art may make all kinds of variation or modification within the scope of appended claims.