Handling time information in communications systems

Abstract

A method of handling time information in a communications system ( 100 ) comprising: receiving a message at a proxy entity such as a P-CSCF ( 110, 112, 114 ) in an IP Multimedia Subsystem (IMS) core network ( 108 ); determining a time zone offset between a local time of a terminal and a core network time; providing the time zone offset to a network element ( 116 ) in the core network; and generating a time stamp in the network element adjusted to correspond to the local time.

1 . A method of handling time information in a communications system comprising:
 receiving a message at a proxy entity in a core network;   determining a time zone offset between a local time and a core network time;   providing the time zone offset to a network element in the core network; and   generating a time stamp in the core network adjusted to correspond to the local time.   
     
     
         2 . A method according to  claim 1  in which there is a plurality of proxy entities. 
     
     
         3 . A method according to  claim 2  in which network elements of the core network comprise a mapping table containing a mapping between the addresses of proxy entities linked to the core network and time zone offset information. 
     
     
         4 . A method according to  claim 3  in which the network elements are capable of using the address of a proxy entity and a corresponding time zone offset to derive local time of a terminal or a network element. 
     
     
         5 . A method according to  claim 1  in which there is a common proxy entity serving a plurality of time zones. 
     
     
         6 . A method according to  claim 5  in which the core network provides services via a plurality of access networks. 
     
     
         7 . A method according to  claim 6  in which the user-related time zone offset is provided from an access network in which a terminal is located to the core network. 
     
     
         8 . A method according to  claim 6  in which a relationship between a terminal and its corresponding time zone is provided by an entity within a particular access network which is responsible for allocating an IP address a terminal. 
     
     
         9 . A method according to  claim 5  in which the proxy entity is pre-configured with a mapping between IP address ranges and time zone offsets. 
     
     
         10 . A method according to  claim 1  in which the message has a header into which the proxy entity places the time zone offset. 
     
     
         11 . A method according to  claim 1  in which the message is provided by the proxy entity to the network element. 
     
     
         12 . A method according to  claim 11  in which the time zone offset is retrieved from the header by the network element and used by that network element, or by an associated network element, to generate a correct local time stamp. 
     
     
         13 . A communications system capable of handling time information in a communications system comprising:
 a core network;   a proxy entity in the core network, the proxy entity being capable of receiving a message; and   a network element in the core network,   wherein the proxy entity is capable of determining a time zone offset between a local time and a core network time and capable of providing the time zone offset to the network element in the core network, the time zone offset being useable to generate a time stamp in the core network adjusted to correspond to the local time.   
     
     
         14 . A core network node for a communications system capable of handling time information in the communications system, the node being capable of receiving a message via an input; and
 wherein the node is capable of determining a time zone offset between a local time and a core network time and is capable of providing the time zone offset to a network element in a core network, the time zone offset being useable to generate a time stamp in the core network adjusted to correspond to the local time.   
     
     
         15 . A computer program product comprising software code that when executed on a computing system performs a method of handling time information in a communications system, the method comprising the steps of:
 receiving a message at a proxy entity in a core network;   determining a time zone offset between a local time and a core network time;   providing the time zone offset to a network element in the core network; and   generating a time stamp in the core network adjusted to correspond to the local time.