Abstract:
The disclosure provides a method of implementing Short Message Service (SMS) for a Next Generation Network (NGN) terminal, comprising: receiving, by an NGN Short Message Center (SMC), a short message transmission request forwarded by a soft switch, wherein the short message transmission request is from an NGN terminal; and transmitting, by the NGN SMC, a short message according to the received short message transmission request. The disclosure also provides a system of implementing SMS for an NGN terminal, and an NGN SMC.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to techniques for Next Generation Network (NGN), and more particularly, to a method, system and NGN Short Message Service (SMS) of implementing SMS for an NGN terminal. 
       BACKGROUND 
       [0002]    NGN is a next generation network incorporating circuit switching networks such as Public Switched Telephone Network (PSTN) or Public Land Mobile Network (PLMN) and packet switching IP networks. In NGN, integrated services of voice, video, data, and the like, may be deployed. 
         [0003]    NGN uses a unified IP/MPLS carrier network having Quality of Service (QoS) capability to support various services. Soft switch having packet switching control capability is a core component in NGN. The call control protocol of NGN is Session Initiation Protocol (SIP). NGN may provide access to a conventional circuit switching network via a signaling gateway and a relay gateway so that interoperability with the circuit switching network may be achieved. 
         [0004]    For SMS which is a basic data service in the conventional circuit switching network, interoperability has been achieved among terminals based on Global System for Mobile communications (GSM), Code Division Multiple Access (CDMA), Personal Handy-phone System (PHS) and the like. However, due to the complexity and the diversity of NGN terminals, there is no good solution at present to normalize the technical standards for short message transmission and reception by NGN terminals for various manufacturers. 
         [0005]    Presently, SMS have been implemented for some NGN terminals.  FIG. 1  illustrates the configuration of an existing system of implementing SMS for an NGN terminal. As shown in  FIG. 1 , the NGN terminal communicates with the value-added service platform directly with a private protocol. The value-added service platform uses the standardized Short Message Peer to Peer (SMPP) to access the short message system. Registration and de-registration messages need to be redefined between the NGN terminal and the value-added service platform. Furthermore, both parties need to maintain heart-beat messages to detect whether the NGN terminal is on line. As an access part between the NGN terminal and the short message system, the value-added service platform further needs to perform conversions between the private protocol and the standardized short message protocol. 
         [0006]    The method with which the system of  FIG. 1  implements SMS may be summarized generally as follows. 
         [0007]    1) The NGN terminal transmits a short message as follows. The NGN terminal establishes an IP link with the value-added service platform. The short message is transmitted to the value-added service platform via a private protocol over the established IP link. The value-added service platform decodes the received short message, and then encodes the decoded message into a packet based on the standardized short message protocol, which is forwarded to the short message system. In this way, the NGN terminal may transmit a short message. 
         [0008]    2) The NGN terminal receives a short message as follows. The short message system transmits the short message to the value-added service platform in a standardized short message protocol packet. The value-added service platform converts the received short message into a packet compliant with the private protocol format, which is forwarded to the NGN terminal over the IP link established between the NGN terminal and the value-added service platform. In this way, the NGN terminal may receive a short message. 
         [0009]    3) The NGN terminal acquires an off-line short message as follows. After the NGN terminal is on-line, the value-added service platform sends the off-line short message for the NGN terminal to the NGN terminal just as the NGN terminal receives a short message. 
         [0010]    In the existing methods of implementing SMS for an NGN terminal, each NGN terminal has to be registered with the value-added service platform, and establishes an IP link with the value-added service platform, and heart-beat is maintained. Shortcomings are caused as follows. 
         [0011]    (1) A registration message is transmitted to the value-added service platform when the NGN terminal logs in, and a de-registration message is transmitted to the value-added service platform when the NGN terminal logs out. Moreover, a heart-beat message is maintained between the NGN terminal and the value-added service platform. Thus, the overhead will be increased for the value-added service platform. The NGN terminal transmits a heart-beat message to the value-added service platform. Upon receipt of the message, the value-added service platform decodes and processes the private message packet in the heart-beat message, which is then encoded into a message packet based on the private protocol and sent to the NGN terminal as a heart-beat confirmation message. The capability of the Central Processing Unit (CPU) in the value-added service platform is thus wasted additionally, and the system overhead is increased greatly. In an example where ten thousand users are online concurrently, it is assumed that the heart-beat period is 1 minute. As such, the value-added service platform has to process  166  heart-beat messages per second on the average, and meanwhile the session data for the ten thousand users has to be maintained in the memory of the platform. 
         [0012]    (2) According to the protocol, an SIP link already exists between the NGN terminal and the soft switch. Furthermore, the registration, de-registration and heart-beat messages already exist between both parties. But in the existing method, the NGN terminal needs a further IP link to the value-added service platform. As a result, the system is complicated greatly, and the system extensibility is decreased. Moreover, there are several defects when an additional IP link is introduced between the NGN terminal and the value-added service platform. On one hand, the value-added service platform is exposed on the public network so as to be connected by the NGN terminals. Although many solutions have been proposed presently to address the network security, the risk for the value-added service platform to be attacked is increased, and thus the system security risk is increased. On the other hand, in order to decrease the security risk, a security device has to be added to guarantee the network security of the value-added service platform, which causes an increase in the system investments. 
         [0013]    (3) Because a voluntary registration is made to the value-added service platform when the NGN terminal logs in, the NGN terminal has to be configured with the IP address of the value-added service platform first. Once the IP address of the value-added service platform changes, the configurations of all NGN terminals have to be changed accordingly. The maintenance work is substantial and the system maintainability is deceased. 
         [0014]    As described above, the existing solutions are only applicable to networks with IP links established between the NGN terminal and the value-added service platform. For a large number of NGN terminals directly connected to the soft switch at present, only IP links are maintained with the soft switch, and accordingly SMS cannot be implemented yet. Moreover, in the existing solutions, there are shortcomings in terms of both performance and security. In particular, the system complexity is increased, and the system extensibility is weakened. 
       SUMMARY 
       [0015]    In view of the above problems, an embodiment of the invention provides a method of implementing Short Message Service (SMS) for a Next Generation Network (NGN) terminal, which may be applied to various NGN terminals and enhance the system extensibility. 
         [0016]    Another embodiment of the invention provides a system of implementing SMS for an NGN terminal, which may be applied to various NGN terminals and enhance the system extensibility. 
         [0017]    Still another embodiment of the invention provides an NGN SMC, which may be applied to various NGN terminals and enhance the system extensibility. 
         [0018]    Specifically, the solutions of the invention may be implemented as follows. 
         [0019]    A method of implementing SMS for an NGN terminal includes: receiving, by an NGN Short Message Center (SMC), a short message transmission request forwarded by a soft switch, wherein the short message transmission request is from an NGN terminal; and transmitting, by the NGN SMC, a short message according to the received short message transmission request. 
         [0020]    A system of implementing SMS includes a soft switch and an NGN SMC. 
         [0021]    The soft switch is configured to transparently transmit information exchanged between an NGN terminal and the NGN SMC. 
         [0022]    The NGN SMC is configured to receive a short message transmission request from the NGN terminal, and to transmit a short message to the NGN terminal according to the received short message transmission request. 
         [0023]    The NGN SMC includes a short message transmitting unit and/or a short message receiving unit and/or an off-line short message acquiring unit. 
         [0024]    The short message transmitting unit is configured to receive a short message transmission request from the NGN terminal forwarded via the soft switch, and to transmit a short message to the NGN terminal. 
         [0025]    The short message receiving unit is configured to forward a short message reception request to the NGN terminal via the soft switch so that the NGN terminal receives the short message. 
         [0026]    The off-line short message acquiring unit is configured to receive an off-line short message acquisition request forwarded via the soft switch from the NGN terminal, to carry a stored short message for the NGN terminal in an SIP-based message, and to forward the SIP-based message to the NGN terminal via the soft switch. 
         [0027]    From the above solutions, it can be seen that in embodiments of the present invention, SMS may be implemented for various NGN terminals by setting an NGN SMC and extending the SIP message. The NGN terminal may utilize an existing SIP link with the soft switch. The soft switch may transparently transmit SIP messages exchanged between the NGN terminal and the NGN SMC. The NGN terminal may have a capability of transmitting and receiving short messages. And the system maintainability may be enhanced. 
         [0028]    In the system for implementing SMS according to the present invention, the NGN terminal may exchange information with the NGN SMC through the transparent transmission of the soft switch. To the NGN terminal, there is no need for the NGN terminal to establish a private protocol based link with the value-added service platform, and only the existing SIP link is maintained with the soft switch, which enhances the system extensibility and flexibility. Furthermore, as long as the Extensible Markup Language (XML) content carried in the SIP message is extended, it may be readily applied to other services, for example, instant messaging or multimedia short messaging on the NGN terminal. To the NGN SMC acting as the service platform, there is no need to be oriented to all NGN terminals as long as a link is maintained with the soft switch. The system security is improved greatly and the system overhead is saved significantly. In this manner, the NGN SMS may be managed and maintained by the NGN SMC uniformly, which enhances the system maintainability. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]      FIG. 1  illustrates the configuration of an existing system of implementing SMS for an NGN terminal; 
           [0030]      FIG. 2  illustrates the configuration of a system of implementing SMS for an NGN terminal according to an embodiment of the present invention; 
           [0031]      FIG. 3  illustrates an embodiment of implementing SMS for an NGN terminal according to the present invention; 
           [0032]      FIG. 4  illustrates an embodiment for an NGN terminal to transmit a short message according to the present invention; 
           [0033]      FIG. 5  illustrates an embodiment for an NGN terminal to receive a short message according to the present invention; and 
           [0034]      FIG. 6  illustrates an embodiment for an NGN terminal to acquire an off-line short message according to the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0035]    In embodiments of the present invention, the soft switch forwards the short message transmission request to the NGN SMC, and then the NGN SMC transmits a short message according to the received short message transmission request. 
         [0036]    The solutions and advantages of the invention will be more fully understood when considered with respect to further detailed description of the preferred embodiments of the invention taken in conjunction with the accompanying drawings. 
         [0037]      FIG. 2  illustrates the configuration of a system of implementing SMS for an NGN terminal according to an embodiment of the present invention. As shown in  FIG. 2 , the system at least includes an NGN terminal, a soft switch, and an NGN SMC. 
         [0038]    The soft switch is configured to transparently transmit information related to short messages between the NGN terminal and the NGN SMC. 
         [0039]    The NGN SMC has a service function similar to a conventional SMC. Different from the conventional SMC, the protocol for a terminal to access the NGN SMC is SIP. A protocol converting module is thus added to the conventional SMC so that conversions between the SIP and the protocol of the NGN SMC may be enabled. Alternatively, if the protocol inside the NGN SMC is SIP, no protocol conversion is necessary for interaction with the terminal to implement short message transmission. 
         [0040]    In the following embodiments, description is made to examples in which a protocol converting module is provided in the NGN SMC. 
         [0041]    The NGN SMC may include a short message transmitting unit and/or a short message receiving unit and/or an off-line short message acquiring unit. The short message transmitting unit is configured to receive a short message transmission request from the NGN terminal forwarded via the soft switch, to convert the received SIP-based short message transmission request into a request based on its own protocol, and to transmit a short message. The short message receiving unit is configured to convert the short message reception request into an SIP message, and to forward the short message reception request to the NGN terminal via the soft switch so that the NGN terminal receives the short message. The off-line short message acquiring unit is configured to receive an off-line short message acquisition request forwarded via the soft switch from the NGN terminal, to carry a stored short message for the NGN terminal in an SIP-based message, and to forward the SIP-based message to the NGN terminal via the soft switch. 
         [0042]    The link between the NGN terminal and the soft switch is a link based on SIP, which may mainly implement registration, de-registration, heart-beat and call signaling messages. But according the provision of the protocol, the content of the short message cannot be carried. In view of this fact, the existing SIP message is extended to carry SMS in the present invention. The specific implementation may refer to the following embodiments. 
         [0043]      FIG. 3  illustrates an embodiment of implementing SMS for an NGN terminal according to the present invention. In conjunction with  FIG. 2 , the method according to the present invention may include the following steps. 
         [0044]    At step  300 , the soft switch forwards a short message transmission request to the NGN SMC. 
         [0045]    The short message transmission request may use an SIP message carrying information of a Body field, for example, an out-session SIP INFO message or SIP MESSAGE message. The short message transmission request may carry the access code of the NGN SMC. 
         [0046]    To transparently transmit messages between the NGN terminal and the NGN SMC via a soft switch, soft switches from various manufacturers shall support transparent transmission of SIP messages such as an out-session SIP INFO message or SIP MESSAGE message. In other words, the soft switch can identify the extended SIP message according to the present invention. 
         [0047]    The NGN terminal uses SIP messages such as an out-session SIP INFO message or SIP MESSAGE message, to transmit and receive the short message request and response. The soft switch performs transparent transmission, to carry corresponding information in a message body in format of XML. The request and response events for the NGN terminal are shown in Table 1. 
         [0000]    
       
         
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Event 
                 Command code 
               
               
                   
               
             
             
               
                 Short message transmission request 
                 3001 
               
               
                 Short message transmission response 
                 3002 
               
               
                 Return short message transmission forwarding result to 
                 3003 
               
               
                 the terminal 
               
               
                 Return a return notification indicating that the recipient 
                 3004 
               
               
                 receives the short message to the terminal 
               
               
                 Short message reception request 
                 3005 
               
               
                 Off-line short message acquisition request from 
                 3006 
               
               
                 terminal 
               
               
                   
               
             
          
         
       
     
         [0048]    Prior to using the method, the NGN terminal has to be registered with the soft switch. Registration methods are provided in the related protocols, and detailed description is omitted here. Note that if the NGN terminal is not registered with the soft switch, the soft switch rejects the short message transmission request originated from the NGN terminal. Further, the soft switch determines whether the short message transmission request is originated from an IP address already registered in the soft switch, based on the transmitter information carried in the short message transmission request. If the short message transmission request is not originated from an IP address already registered in the soft switch, the short message request originated from the NGN terminal will be rejected. 
         [0049]    Because the NGN terminal transmits the short message request via the soft switch directly, the NGN terminal only needs to be configured with the IP address of the soft switch, without any knowledge of the IP address of the NGN SMC. The access code of the NGN SMC is carried in the Uniform Resource Address request (Request URI) field of the SIP message. Upon receipt of the short message request, the soft switch forwards short message request to the NGN SMC according to the access code of the NGN SMC carried in the Request URI. 
         [0050]    At step  301 , the NGN SMC transmits a short message according to the received short message transmission request. 
         [0051]    At this step, a protocol converting module is provided in the NGN SMC, for converting an SIP-based message from the NGN terminal to a message supported by its own protocol, and transmitting the short message according to the received short message transmission request. 
         [0052]    When the NGN SMC transmits a short message to the NGN terminal, the short message may be carried in an SIP message, such as an SIP INFO message or SIP MESSAGE message. The NGN SMC transmits a short message to the soft switch. Based on the number in the Request URI of the SIP message (that is, the called number), the soft switch transmits the received SIP message transparently to the NGN terminal corresponding to the IP address registered with the called number. Thus, it can be seen that there is no need for the NGN SMC to know the registered address of the NGN terminal. 
         [0053]    Further, if the NGN terminal is not registered, the soft switch may return an error code like 404 to the NGN SMC. 
         [0054]    Note that transparent transmission of the soft switch means that the soft switch forwards the common SIP element in the received SIP message without any change. The common SIP element may include a From header field carrying transmitter information, a To header field carrying recipient information, a Content Type field identifying the context type, a Content Length field, a Status Code, a Body field carrying the short message, and etc. 
         [0055]    If no Body field is carried in the received SIP message, the soft switch may simply discard the SIP message. 
         [0056]    Alternatively, the NGN SMC may use the standardized short message protocol for transmission to common terminals. 
         [0057]    Detailed descriptions are given below with reference to illustrative embodiments to methods for the NGN terminal to transmit a short message, to receive a short message, and to acquire an off-line short message according to embodiments of the present invention. 
         [0058]      FIG. 4  illustrates an embodiment for an NGN terminal to transmit a short message according to the present invention. Consider that the NGN terminal has been registered in the soft switch. As shown in  FIG. 4 , transmission of the short message may include the following steps. 
         [0059]    At step  400 , the NGN terminal initiates a short message transmission request to the NGN SMC via the soft switch. 
         [0060]    After the NGN terminal logs in, the NGN terminal may choose a destination number for transmission of the short message through commonly used tools such as a friend list or a contact list, or choose to transmit a short message via a menu or a task bar. Here, as to how the user transmits a short message via an interface provided at the NGN terminal, it is not within the scope of the present invention. 
         [0061]    The short message transmission request, such as the common SIP element carried in the SIP INFO message, is well known to those skilled in the art, and detailed description is omitted here. Note that the access code of the NGN SMC is carried in the To header field. Furthermore, the short message transmission request must also carry short message transmission event parameters, as shown in Table 2. 
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                   
                   
                 Mandatory/ 
                   
               
               
                 Parameter 
                 Type 
                 Optional 
                 Description 
               
               
                   
               
             
             
               
                 cmd 
                 Integer 
                 Mandatory 
                 Command code corresponding 
               
               
                   
                   
                   
                 to short message transmission 
               
               
                   
                   
                   
                 request 
               
               
                 msgid 
                 String 
                 Mandatory 
                 Identification of a short 
               
               
                   
                   
                   
                 message transmitted from the 
               
               
                   
                   
                   
                 terminal (its uniqueness is 
               
               
                   
                   
                   
                 secured by the terminal) 
               
               
                 recv 
                 String 
                 Mandatory 
                 Number for short message 
               
               
                   
                   
                   
                 reception 
               
               
                 isreturn 
                 Integer 
                 Mandatory 
                 The transmitting terminal 
               
               
                   
                   
                   
                 needs to receive a return 
               
               
                   
                   
                   
                 notification for short message, 
               
               
                   
                   
                   
                 for example, 0 indicates no 
               
               
                   
                   
                   
                 need, 1 indicates a need 
               
               
                 cont 
                 String 
                 Mandatory 
                 Content of the short message 
               
               
                   
               
             
          
         
       
     
         [0062]    At this step, the command code corresponding to the short message transmission request event is 3001 in Table 1. 
         [0063]    Consider that the NGN terminal transmitting a short message chooses to receive a return notification for the short message in this embodiment. 
         [0064]    At step  401 , the NGN SMC returns a short message transmission response such as SIP 200OK to the NGN terminal via the soft switch, and returns the processing result to the NGN terminal. 
         [0065]    In addition to the common SIP element, the SIP 200OK message shall carry short message transmission response event parameters, as shown in Table 3. 
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 3 
               
               
                   
               
               
                   
                   
                 Mandatory/ 
                   
               
               
                 Parameter 
                 Type 
                 Optional 
                 Description 
               
               
                   
               
             
             
               
                 cmd 
                 Integer 
                 Mandatory 
                 Command code corresponding 
               
               
                   
                   
                   
                 to short message transmission 
               
               
                   
                   
                   
                 response 
               
               
                 res 
                 Integer 
                 Mandatory 
                 The processing result returned 
               
               
                   
                   
                   
                 for short message transmission, 
               
               
                   
                   
                   
                 for example, 1 indicates short 
               
               
                   
                   
                   
                 message transmission ready, −1 
               
               
                   
                   
                   
                 indicates system abnormity, −78 
               
               
                   
                   
                   
                 indicates short message transmission 
               
               
                   
                   
                   
                 failure, −79 indicates short message 
               
               
                   
                   
                   
                 forwarding forbidden, and so on. 
               
               
                   
               
             
          
         
       
     
         [0066]    At this step, the command code corresponding to the short message transmission request event is 3002 in Table 1 
         [0067]    At step  402 , the NGN SMC returns a short message forwarding response to the NGN terminal via the soft switch, such as the SIP INFO message, and returns the short message forwarding result to the NGN terminal. 
         [0068]    In addition to the common SIP element, the SIP INFO message shall carry short message forwarding response event parameters, that is, a short message transmission forwarding result event parameter is returned to the terminal, as shown in Table 4. 
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 4 
               
               
                   
               
               
                   
                   
                 Mandatory/ 
                   
               
               
                 Parameter 
                 Type 
                 Optional 
                 Description 
               
               
                   
               
             
             
               
                 cmd 
                 Integer 
                 Mandatory 
                 Command code for short message 
               
               
                   
                   
                   
                 forwarding response 
               
               
                 msgid 
                 String 
                 Mandatory 
                 Identification of a short message 
               
               
                   
                   
                   
                 transmitted from a terminal 
               
               
                 res 
                 Integer 
                 Mandatory 
                 The returned short message 
               
               
                   
                   
                   
                 forwarding result, for example, 1 
               
               
                   
                   
                   
                 indicates short message forwarding 
               
               
                   
                   
                   
                 success, −1 indicates system 
               
               
                   
                   
                   
                 abnormity, −78 indicates short 
               
               
                   
                   
                   
                 message forwarding failure, −79 
               
               
                   
                   
                   
                 indicates short message being 
               
               
                   
                   
                   
                 obsolete, and so on 
               
               
                   
               
             
          
         
       
     
         [0069]    At this step, the command code corresponding to the short message forward response event is 3003 in Table 1. 
         [0070]    At step  403 , after receiving the short message forwarding response, the NGN terminal will typically return a response to the NGN SMC via the soft switch, indicating that it has obtained information whether the short message is transmitted successfully. 
         [0071]    At step  404 , after the NGN SMC processes the short message transmission request and receives the return notification returned from the short message recipient (the destination number), the NGN SMC returns a reception response in the SIP INFO message to the NGN terminal via the soft switch. 
         [0072]    In addition to the common SIP element, the reception response shall carry reception response event parameters, that is, a return notification event parameter is returned for indicating that the short message is received at the terminal, as shown in Table 5. 
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 5 
               
               
                   
               
               
                   
                   
                 Mandatory/ 
                   
               
               
                 Parameter 
                 Type 
                 Optional 
                 Description 
               
               
                   
               
             
             
               
                 cmd 
                 Integer 
                 Mandatory 
                 Command code for short message 
               
               
                   
                   
                   
                 transmission and return 
               
               
                   
                   
                   
                 notification 
               
               
                 msgid 
                 String 
                 Mandatory 
                 Identification of a short message 
               
               
                   
                   
                   
                 transmitted from a terminal 
               
               
                 secvt 
                 String 
                 Mandatory 
                 Short message delivery time in 
               
               
                   
                   
                   
                 format of yyyymmddhhmmss 
               
               
                 res 
                 Integer 
                 Mandatory 
                 The processing result returned for the 
               
               
                   
                   
                   
                 short message transmission result, 
               
               
                   
                   
                   
                 for example, 1 indicates that the 
               
               
                   
                   
                   
                 terminal receives the short message 
               
               
                   
                   
                   
                 successfully, −1 indicates system 
               
               
                   
                   
                   
                 abnormity, −78 indicates short 
               
               
                   
                   
                   
                 message transmission failure, −79 
               
               
                   
                   
                   
                 indicates short message being 
               
               
                   
                   
                   
                 obsolete, and so on 
               
               
                   
               
             
          
         
       
     
         [0073]    At this step, the command code corresponding to the reception response event is 3004 in Table 1. 
         [0074]    At step  405 , after receiving the reception response, the NGN terminal generally will return a confirmation response to the NGN SMC via the soft switch, indicating its knowledge regarding whether the recipient has received the short message successfully. 
         [0075]    Note that when the NGN terminal multicasts a short message, a single short message may be transmitted several times with the method shown in  FIG. 4 . 
         [0076]      FIG. 5  illustrates an embodiment for an NGN terminal to receive a short message according to the present invention. Consider that the NGN terminal has been registered in the soft switch. As shown in  FIG. 5 , reception of the short message may include the following steps. 
         [0077]    At step  500 , the NGN SMC transmits a short message reception request such as an SIP INFO message, to the NGN terminal via the soft switch. 
         [0078]    In addition to the common SIP element, the short message reception request shall carry a short message reception event parameter, as shown in Table 6. 
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 6 
               
               
                   
               
               
                   
                   
                 Mandatory/ 
                   
               
               
                 Parameter 
                 Type 
                 Optional 
                 Description 
               
               
                   
               
             
             
               
                 cmd 
                 Integer 
                 Mandatory 
                 Command code corresponding 
               
               
                   
                   
                   
                 to short message reception 
               
               
                   
                   
                   
                 request 
               
               
                 send 
                 String 
                 Mandatory 
                 The number of a short message 
               
               
                   
                   
                   
                 transmitter 
               
               
                 time 
                 String 
                 Mandatory 
                 Delivery time by NGN SMC to the 
               
               
                   
                   
                   
                 receiving terminal in format of 
               
               
                   
                   
                   
                 yyyymmddhhmmss 
               
               
                 cont 
                 String 
                 Mandatory 
                 Content of the short message 
               
               
                   
               
             
          
         
       
     
         [0079]    At this step, the command code corresponding to the short message reception event is 3005 in Table 1. 
         [0080]    At step  501 , after receiving the short message, the NGN terminal generally returns a confirmation message such as an SIP 200OK message via the soft switch to the NGN SMC, indicating that the short message is received. 
         [0081]      FIG. 6  illustrates an embodiment for an NGN terminal to acquire an off-line short message according to the present invention. When the NGN terminal is off-line, if a short message is transmitted to the NGN terminal, the NGN SMC may carry the short message in an SIP INFO message and send it to the soft switch, as shown in  FIG. 5 . If the soft switch finds that the terminal is not on-line, it returns a 404 error code to the NGN SMC. At this point, the NGN SMC stores the short message which is not yet transmitted successfully to the NGN terminal. When the NGN terminal goes on-line and is registered with the soft switch, the method for the NGN terminal to acquire the off-line short message according to the present invention may include the following steps. 
         [0082]    At step  600 , the NGN terminal transmits an off-line short message acquisition request such as an SIP INFO message to the NGN SMC via the soft switch. 
         [0083]    In addition to the common SIP element, the off-line short message acquisition request shall carry a terminal off-line short message acquisition request event parameter, as shown in Table 7. 
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 7 
               
               
                   
               
               
                   
                   
                 Mandatory/ 
                   
               
               
                 Parameter 
                 Type 
                 Optional 
                 Description 
               
               
                   
               
             
             
               
                 cmd 
                 Integer 
                 Mandatory 
                 Command code for the terminal 
               
               
                   
                   
                   
                 to acquire an off-line short 
               
               
                   
                   
                   
                 message 
               
               
                   
               
             
          
         
       
     
         [0084]    At this step, the command code corresponding to the terminal off-line short message acquisition request event is 3006 in Table 1. 
         [0085]    At step  601 , the NGN SMC processes the received off-line short message request. If any short message not transmitted for the NGN terminal is stored, an SIP 200OK message is returned to the NGN terminal, and the off-line short message is transmitted to the NGN terminal. 
         [0086]    At this step, the method for transmitting the off-line short message to the NGN terminal is shown in  FIG. 5 , and detailed description is omitted here. 
         [0087]    In the method and system of implementing SMS for an NGN terminal according to the present invention, SMS may be implemented for various NGN terminals by setting an NGN SMC and extending the SIP message. In the present invention, the NGN SMC is transparent to the NGN terminal. The NGN terminal may utilize an existing SIP communication link with the soft switch, and the soft switch may transparently transmit SIP messages between the NGN terminal and the NGN SMC. The overall system performance may be improved, and a high system extensibility and security may be obtained. Also, the system&#39;s subsequent extensibility to other communication capability may be supported so that an NGN terminal may have functions such as instant messaging, multimedia messaging and the like. 
         [0088]    The invention has been described above with reference to preferred embodiments, which are not used to limit the scope of the invention. Within the scope of the invention, those skilled in the art may make various changes, equivalent substitutions and improvements without departing from the spirit and principle of the invention.