Light-Weight RRC Connection Setup in Multi-RAT Network

Abstract

The present disclosure generally relates to the field of Radio Resource Control (RRC). More specifically, the present disclosure relates to techniques of supporting and initiating RRC connection establishment in a wireless communication network. A method embodiment relates to supporting RRC connection establishment in a wireless communication network and comprises setting up context information during a first RRC connection establishment procedure to establish a first RRC connection towards a radio access network element (200) of the wireless communication network implementing a first Radio Access Technology (RAT). The context information is associated with a wireless communication device (100) of the wireless communication network and is usable for a second RRC connection establishment procedure to establish a second RRC connection towards a radio access network element of the wireless communication network implementing a second RAT.

What is claimed is: 
     
         1 . A method of supporting Radio Resource Control (RRC) connection establishment in a wireless communication network, the method comprising:
 setting up context information during a first RRC connection establishment procedure to establish a first RRC connection towards a radio access network element of the wireless communication network implementing a first Radio Access Technology (RAT) the context information being associated with a wireless communication device of the wireless communication network and usable for a second RRC connection establishment procedure to establish a second RRC connection towards a radio access network element of the wireless communication network implementing a second RAT.   
     
     
         2 . The method of  claim 1 , wherein the step of preparing comprises receiving, by the radio access network element implementing the first RAT, the context information or information needed for setting up the context information. 
     
     
         3 . The method of  claim 1 , wherein the radio access network element implementing the first RAT corresponds to or is different from the radio access network element implementing the second RAT. 
     
     
         4 . The method of  claim 3 , wherein, if the radio access network element implementing the first RAT is different from the radio access network element implementing the second RAT, the method comprises providing, by the radio access network element implementing the first RAT, the context information to the radio access network element implementing the second RAT. 
     
     
         5 . The method of  claim 1 , the method comprising providing the wireless communication device with information related to the establishment of the second RRC connection. 
     
     
         6 . The method of  claim 5 , the method comprising:
 providing the information related to the establishment of the second RRC connection in a Downlink, DL, message of the first RRC connection establishment procedure, or   providing the information related to the establishment of the second RRC connection via broadcast system information.   
     
     
         7 . The method of  claim 5 , wherein the information related to the establishment of the second RRC connection comprises at least one of:
 a cell identity of the cell associated with the radio access network element implementing the second RAT;   an identifier to be used when accessing the radio access network element implementing the second RAT;   access information for accessing the radio access network element implementing the second RAT;   information about conditions or trigger events indicating when to connect to the radio access network element implementing the second RAT; and   security re-activation information for the second RRC connection establishment procedure.   
     
     
         8 . A method of initiating Radio Resource Control (RRC) connection establishment in a wireless communication network, the method comprising:
 setting up context information during a first RRC connection establishment procedure to establish a first RRC connection towards a radio access network element of the wireless communication network implementing a first Radio Access Technology (RAT) the context information being associated with a wireless communication device of the wireless communication network and usable for a second RRC connection establishment procedure to establish a second RRC connection towards a radio access network element of the wireless communication network implementing a second RAT; and   initiating, using the context information, the second RRC connection establishment procedure to establish the second RRC connection towards the radio access network element of the wireless communication network implementing the second RAT.   
     
     
         9 . The method of  claim 8 , the method comprising in parallel establishing the first RRC connection towards the radio access network element implementing the first RAT and the second RRC connection towards the radio access network element implementing the second RAT. 
     
     
         10 . The method of  claim 9 , the method comprising establishing the second RRC connection towards the radio access network element implementing the second RAT by using the context information. 
     
     
         11 . The method of  claim 10 , the method comprising maintaining the first RRC connection towards the radio access network element implementing the first RAT and the second RRC connection towards the radio access network element implementing the second RAT at the same time. 
     
     
         12 . The method of  claim 11 , the method comprising establishing the second RRC connection towards the radio access network element implementing the second RAT, if the first RRC connection towards the radio access network element implementing the first RAT is lost. 
     
     
         13 . The method of  claim 12 , the method comprising establishing the second RRC connection towards the radio access network element implementing the second RAT based on at least one of a trigger event and a network command. 
     
     
         14 . The method of  claim 13 , wherein the trigger event comprises or is a Radio Link Failure, RLF, of the RRC connection towards the radio access network element implementing the first RAT. 
     
     
         15 . A radio access network element for supporting Radio Resource Control (RRC) connection establishment in a wireless communication network, the radio access network element comprising:
 a set-up component configured to set up context information during a first RRC connection establishment procedure to establish a first RRC connection towards a radio access network element of the wireless communication network implementing a first Radio Access Technology (RAT) the context information being associated with a wireless communication device of the wireless communication network and usable for a second RRC connection establishment procedure to establish a second RRC connection towards a radio access network element of the wireless communication network implementing a second RAT.