Security key refresh for dual connectivity

Abstract

Embodiments have a master eNB with a control plane and optional data plane to user equipment and a secondary eNB with a data plane to the user equipment. The user equipment thus uses both the master eNB and the secondary eNB for data communications while receiving control information from only the master eNB. The master eNB and secondary eNB are connected with an X2 interface. When the secondary eNB desires to refresh its security key, it informs the master eNB using the X2 interface. The master eNB then uses its control plane with the user equipment to initiate a security key refresh for the secondary eNB.

1 .- 25 . (canceled) 
     
     
         26 . A method performed by a first enhanced Node B (eNB) comprising:
 receiving, from a second eNB, a request to refresh a security key used by the second eNB;   sending a release request to the second eNB that causes the second eNB to release resources dedicated to a User Equipment (UE);   sending a remove request to the UE that causes the UE to remove the second eNB from its eNB list;   sending a Secondary Cell Addition/Modification message to the second eNB, the Secondary Cell Addition/Modification message comprising configuration information for the second eNB;   sending an eNB addition request to the UE that causes the UE to add the second eNB to its eNB list.   
     
     
         27 . The method of  claim 26 , wherein the release request and the configuration information are sent in the same message to the second eNB. 
     
     
         28 . The method of  claim 26 , wherein sending the release request and sending the remove request are part of a cell release procedure. 
     
     
         29 . The method of  claim 26 , wherein sending the Secondary Cell Addition/Modification message and sending the eNB addition request are part of a cell addition procedure. 
     
     
         30 . The method of  claim 26 , wherein the second eNB is a secondary cell eNB. 
     
     
         31 . A wireless device comprising:
 at least one antenna;   transceiver circuitry coupled to the at least one antenna;   memory;   a processor coupled to the memory and transceiver circuitry; and   instructions, stored in the memory, which when executed cause the processor to:
 receive, from an eNB, a request to refresh a security key used by the eNB; 
 send, to a User Equipment (UE), an RRC signaling request causing the UE to refresh a security key for radio bearers served by the eNB; 
 receive, from the UE, a message indicating that the refresh for the security key has been completed. 
   
     
     
         32 . The device of  claim 31 , wherein the RRC signaling request uses an RRCConnectionReconfiguration message. 
     
     
         33 . The device of  claim 31 , RRC signaling request further comprises a timing reference indicating a timing reference from which the UE should begin using the refreshed security key. 
     
     
         34 . The device of  claim 31 , further comprising sending, to the eNB, a security key refresh acknowledgment message. 
     
     
         35 . The device of  claim 34 , wherein the security key refresh acknowledgment message comprises a timing reference from which the eNB should begin using the refreshed security key. 
     
     
         36 . The device of  claim 31 , wherein the message indicating that the refresh for the security key has been completed uses an RRCConnectionReconfigurationComplete message. 
     
     
         37 . A machine readable medium having executable instructions embodied thereon that, when executed, configure a device to:
 receive, from a second eNB, a request to refresh a security key used by the second eNB;   send, to a User Equipment (UE), an RRC signaling request causing the UE to refresh a security key for radio bearers served by the second eNB;   receive, from the UE, a message indicating that the refresh for the security key has been completed.   
     
     
         38 . The machine readable medium of  claim 37 , wherein the RRC signaling request uses an RRCConnectionReconfiguration message. 
     
     
         38 . The machine readable medium of  claim 37 , RRC signaling request further comprises a timing reference indicating a timing reference from which the UE should begin using the refreshed security key. 
     
     
         38 . The machine readable medium of  claim 37 , further comprising sending, to the second eNB, a security key refresh acknowledgment message. 
     
     
         39 . A method performed by a secondary enhanced Node B (eNB) comprising:
 sending, to a master eNB, a request to refresh a security key used by the secondary eNB;   receiving a release request from the master eNB that causes the secondary eNB to release resources dedicated to a User Equipment (UE);   receiving Radio Resource Control (RRC) configuration information from the master eNB, the RRC configuration information comprising a security configuration for the secondary eNB;   refreshing the security key according to the received RRC configuration information.   
     
     
         40 . The method of  claim 39 , wherein the release request and the RRC configuration information are received in the same message. 
     
     
         41 . The method of  claim 39 , wherein the release request is part of a cell release procedure. 
     
     
         42 . The method of  claim 39 , wherein the RRC configuration information is part of a cell addition procedure. 
     
     
         43 . The method of  claim 39 , wherein refreshing the security key comprises deriving a new K eNB . 
     
     
         44 . User Equipment comprising:
 at least one antenna;   transceiver circuitry coupled to the at least one antenna;   memory;   a processor coupled to the memory and transceiver circuitry; and   instructions, stored in the memory, which when executed cause the processor to:
 receive, via the at least one antenna and transceiver circuitry, a control message from an enhanced Node B (eNB) requesting refresh of a security key used to communicate with a second eNB; 
 derive a new K eNB  used by the UE to communicate with the second eNB. 
   
     
     
         45 . The UE of  claim 44  wherein the control message is a Radio Resource Control (RRC) Connection Reconfiguration message. 
     
     
         46 . The UE of  claim 44  wherein the control message further comprises a timing reference indicating the time at which the new K eNB  should be used to communicate with the second eNB. 
     
     
         47 . The UE of  claim 44  wherein the eNB is a master eNB and the second eNB is a secondary eNB. 
     
     
         48 . The UE of  claim 44 , wherein the instructions further cause the processor to send, via the transceiver circuitry, a RRC Reconfiguration Complete message.