Efficient downlink transmission is implemented. A terminal apparatus includes: a receiver configured to receive a sequence of bits in a physical downlink control channel, wherein the sequence of bits is scrambled with a scrambling sequence initialized by cinit, the cinit is given based at least on NID and NRNTI, the NID is given based at least on a higher layer parameter Control-scrambling-Identity in a case that the higher layer parameter Control-scrambling-Identity is configured and the NRNTI is given based at least on a Cell-Radio Network Temporary Identifier (C-RNTI), and the NID is given based at least on a physical layer cell identity in a case that the higher layer parameter Control-scrambling-Identity is configured and the NRNTI is not given based on the C-RNTI.