Communication related to network slice information

Abstract

A base station ( 1 ) controls state transitions of a radio terminal ( 2 ) among first to third RRC states. In addition, the base station ( 1 ) explicitly or implicitly informs the radio terminal ( 2 ) about whether a network slice configured in the radio terminal ( 2 ) for data communication at least in the first RRC state is available in each cell included in a RAN notification area configured by a RAN ( 3 ). It is thus, for example, possible to allow a radio terminal in a first state (e.g., RRC_INACTIVE state) to be easily aware of the availability of network slices in a cell to be reselected or a reselected cell.

1 . A method of a radio terminal, the method comprising:
 receiving broadcast information from a RAN node, the broadcast information including first information which associates Random Access Channel (RACH) preamble with second information identifying a network slice; and   transmitting RACH preamble based on the broadcast information.   
     
     
         2 . The method of the radio terminal according to  claim 1 , wherein the RAN node supports the network slice identified by the second information. 
     
     
         3 . The method of the radio terminal according to  claim 1 , wherein the radio terminal communicates with the RAN node using the network slice identified by the second information. 
     
     
         4 . The method of the radio terminal according to  claim 1 , wherein the radio terminal is RRC_INACTIVE state. 
     
     
         5 . A method of a RAN node, the method comprising:
 transmitting broadcast information, the broadcast information including first information which associates Random Access Channel (RACH) preamble with second information identifying a network slice; and   receiving RACH preamble which is transmitted from a radio terminal based on the broadcast information.   
     
     
         6 . The method of the RAN node according to  claim 5 , further comprising setting the broadcast information to include the first information which associates the RACH preamble with the second information. 
     
     
         7 . The method of the RAN node according to  claim 5 , wherein the RAN node supports the network slice identified by the second information. 
     
     
         8 . The method of the RAN node according to  claim 5 , wherein the RAN node communicates with the radio terminal using the network slice identified by the second information.