Apparatus related to dual connectivity

Abstract

To enable reduction of the occurrence of unnecessary operations in a case with a SCG bearer. An apparatus of the present invention includes: a first communication processing unit configured to communicate with a terminal apparatus over a master cell group (MCG) bearer for dual connectivity of the terminal apparatus; and a second communication processing unit configured to receive, from a secondary base station which communicates with the terminal apparatus over a secondary cell group (SCG) bearer for the dual connectivity, a first message requesting a release of the secondary base station. The second communication processing unit is configured to transmit, to the secondary base station, a second message indicating a rejection of the release.

What is claimed is: 
     
         1 . An apparatus comprising:
 a memory storing instructions; and   one or more processors configured to execute the instructions to:
 communicate with a terminal apparatus over a master cell group (MCG) bearer for dual connectivity of the terminal apparatus; 
 receive, from a secondary base station which communicates with the terminal apparatus over a secondary cell group (SCG) bearer for the dual connectivity, a first message requesting a release of the secondary base station; and 
 transmit, to the secondary base station, a second message indicating a rejection of the release. 
   
     
     
         2 . The apparatus according to  claim 1 , wherein the first message is an SENB RELEASE REQUIRED message. 
     
     
         3 . The apparatus according to  claim 1 , wherein the second message is an SENB RELEASE CONFIRM message including an information element indicating the rejection of the release. 
     
     
         4 . The apparatus according to  claim 3 , wherein the information element is a Release Reject IE. 
     
     
         5 . The apparatus according to  claim 1 , wherein the second message is an SENB RELEASE REJECT message. 
     
     
         6 . The apparatus according to  claim 1 , wherein the one or more processors are configured to execute the instructions to transmit the second message to the secondary base station when the release is not accepted. 
     
     
         7 . The apparatus according to  claim 6 , wherein the one or more processors are configured to execute the instructions to transmit, to the secondary base station, a third message indicating confirmation of the release, when the release is accepted. 
     
     
         8 . The apparatus according to  claim 7 , wherein the third message is an SENB RELEASE CONFIRM message. 
     
     
         9 . The apparatus according to  claim 1 , wherein the second message includes wait time information indicating a time period for waiting before the secondary base station initiates a next release procedure. 
     
     
         10 . The apparatus according to  claim 9 , wherein the wait time information is a Time to wait IE. 
     
     
         11 . The apparatus according to  claim 1 , wherein the one or more processors are configured to execute the instructions to transmit, to the secondary base station, stop information indicating stop of a function related to inactivity of the terminal apparatus. 
     
     
         12 . The apparatus according to  claim 11 , wherein the stop information is a User Inactivity function Indication IE indicating the stop. 
     
     
         13 . The apparatus according to  claim 11 , wherein the second message includes the stop information. 
     
     
         14 . The apparatus according to  claim 11 , wherein the one or more processors are configured to execute the instructions to transmit, to the secondary base station, an SENB ADDITION REQUEST message including the stop information or an SENB MODIFICATION REQUEST message including the stop information. 
     
     
         15 . The apparatus according to  claim 1 , wherein the one or more processors are configured to execute the instructions to transmit, to the secondary base station, a fourth message including behaviour-related information related to behaviour of the terminal apparatus. 
     
     
         16 . The apparatus according to  claim 15 , wherein the behavior-related information is an Expected UE Behaviour IE. 
     
     
         17 . The apparatus according to  claim 15 , wherein the fourth message is an SENB ADDITION REQUEST message or an SENB MODIFICATION REQUEST message. 
     
     
         18 . The apparatus according to  claim 1 , wherein
 the SCG bearer is a bearer whose communication protocol uses resources of the secondary base station, and   the one or more processors are configured to execute the instructions to transmit the second message indicating the rejection of the release to the secondary base station when the first message requesting the release of the secondary base station is received from the secondary base station in response to inactivity of the terminal apparatus detected by the secondary base station.   
     
     
         19 . An apparatus comprising:
 a memory storing instructions; and   one or more processors configured to execute the instructions to:
 communicate with a terminal apparatus over a SCG bearer for dual connectivity of the terminal apparatus; 
 transmit, to a master base station which communicates with the terminal apparatus over a MCG bearer for the dual connectivity, a first message requesting a release of a secondary base station which communicates with the terminal apparatus over the SCG bearer; and 
 receive, from the master base station, a second message indicating a rejection of the release. 
   
     
     
         20 . A method comprising:
 communicating with a terminal apparatus over a master cell group (MCG) bearer for dual connectivity of the terminal apparatus;   receiving, from a secondary base station which communicates with the terminal apparatus over a secondary cell group (SCG) bearer for the dual connectivity, a first message requesting a release of the secondary base station; and   transmitting, to the secondary base station, a second message indicating a rejection of the release.