Patent ID: 10952099

Abstract:
A radio station (2) transmits or receives, to or from a radio terminal (1) in a second cell (23, 24), a CP message containing a NAS message or an RRC message or both, when a predetermined condition is satisfied. The second cell (23, 24) uses a RAT different from that of the first cell, and is used in addition and subordinate to the first cell. The predetermined condition relates to at least one of: (a) a content or type of the CP message; (b) a type of a signalling radio bearer used to transmit the CP message; (c) a transmission cause of the CP message; and (d) a type of a core network associated with the NAS message. It is thus, for example, possible to contributing to efficient transmission of control plane (CP) messages in a radio architecture that provides interworking of two different Radio Access Technologies (RATs).