Radio access network node, radio terminal, and methods therefor

Abstract

A master RAN node (1) associated with a master RAT (1) communicates with a secondary RAN node (2) associated with a secondary RAT and provides a radio terminal (3) with dual connectivity that uses the master RAT and the secondary RAT. In response to receiving, from the radio terminal (3) or a core network (4), terminal capability information indicating that the radio terminal (3) supports the split bearer, the master RAN node (1) uses a PDCP entity, which provides unified PDCP functionalities, for a master cell group split bearer for the radio terminal (3).

1 . A method of a User Equipment (UE), the method comprising:
 sending, to a network, UE capability information related to a split bearer in a Dual Connectivity (DC);   receiving a Radio Resource Control (RRC) message from the network; and   changing, based on the received RRC message, a first Packet Data Convergence Protocol (PDCP) entity, which is located at the UE, from a first PDCP function to a second PDCP function,   wherein the first PDCP function is used for a Master Cell Group (MCG) bearer by the first PDCP entity,   wherein the second PDCP function is used for the split bearer by the UE, and   wherein the split bearer includes a first split bearer split at a Master Node (MN) in the DC and a second split bearer split at a Secondary Node (SN) in the DC.   
     
     
         2 . The method according to  claim 1 ,
 wherein the UE changes the first PDCP entity from the first PDCP function to the second PDCP function by re-establishing or reconfiguring the first PDCP entity.   
     
     
         3 . The method according to  claim 1 ,
 wherein the second PDCP function is also used for the MCG bearer by the first PDCP entity.   
     
     
         4 . The method according to  claim 1 ,
 wherein the second PDCP function is also used for a Secondary Cell Group (SCG) bearer by the UE.   
     
     
         5 . The method according to  claim 1 ,
 wherein the second PDCP function is also used for the first split bearer by a second PDCP entity located at the MN, and   wherein the second PDCP function is also used for the second split bearer by a third PDCP entity located at the SN.   
     
     
         6 . The method according to  claim 1 ,
 wherein the MN is associated with a first Radio Access Technology (RAT), and   wherein the SN is associated with a second RAT different from the first RAT.   
     
     
         7 . The method according to  claim 1 ,
 wherein the RRC message is an RRC Reconfiguration message.   
     
     
         8 . The method according to  claim 1 ,
 wherein the second PDCP function is related to a New Radio (NR) PDCP.   
     
     
         9 . The method according to  claim 1 ,
 wherein the first split bearer is a first type split bearer split at the MN, and   wherein the second split bearer is a second type split bearer split at the SN.   
     
     
         10 . The method according to  claim 1 ,
 wherein a type of the split bearer includes a first type split at the MN and a second type split at the SN.   
     
     
         11 . A User Equipment (UE) comprising:
 a memory; and   a processor coupled with the memory,   wherein the processor is configured to:
 send, to a network, UE capability information related to a split bearer in a Dual Connectivity (DC); 
 receive a Radio Resource Control (RRC) message from the network; and 
 change, based on the received RRC message, a first Packet Data Convergence Protocol (PDCP) entity, which is located at the UE, from a first PDCP function to a second PDCP function, 
   wherein the first PDCP function is used for a Master Cell Group (MCG) bearer by the first PDCP entity,   wherein the second PDCP function is used for the split bearer by the UE, and   wherein the split bearer includes a first split bearer split at a Master Node (MN) in the DC and a second split bearer split at a Secondary Node (SN) in the DC.   
     
     
         12 . The UE according to  claim 11 ,
 wherein the UE changes the first PDCP entity from the first PDCP function to the second PDCP function by re-establishing or reconfiguring the first PDCP entity.   
     
     
         13 . The UE according to  claim 11 ,
 wherein the second PDCP function is also used for the MCG bearer by the first PDCP entity.   
     
     
         14 . The UE according to  claim 11 ,
 wherein the second PDCP function is also used for a Secondary Cell Group (SCG) bearer by the UE.   
     
     
         15 . The UE according to  claim 11 ,
 wherein the second PDCP function is also used for the first split bearer by a second PDCP entity located at the MN, and   wherein the second PDCP function is also used for the second split bearer by a third PDCP entity located at the SN.   
     
     
         16 . The UE according to  claim 11 ,
 wherein the MN is associated with a first Radio Access Technology (RAT), and   wherein the SN is associated with a second RAT different from the first RAT.   
     
     
         17 . The UE according to  claim 11 ,
 wherein the RRC message is an RRC Reconfiguration message.   
     
     
         18 . The UE according to  claim 11 ,
 wherein the second PDCP function is related to a New Radio (NR) PDCP.   
     
     
         19 . The UE according to  claim 11 ,
 wherein the first split bearer is a first type split bearer split at the MN, and   wherein the second split bearer is a second type split bearer split at the SN.   
     
     
         20 . The UE according to  claim 11 ,
 wherein a type of the split bearer includes a first type split at the MN and a second type split at the SN.