Terminal apparatus, base station apparatus, and communication method

A base station apparatus comprising:

• reception circuitry configured to and/or programmed to receive a random access preamble on a Physical Random Access Channel (PRACH), the random access preamble being transmitted from a terminal apparatus based on a PRACH mask index included in a Physical Downlink Control Channel (PDCCH) order, and
• transmission circuitry configured to and/or programmed to transmit downlink control information with Cyclic Redundancy Check (CRC) parity bits scrambled by a Random Access-Radio Network Temporary Identifier (RA-RNTI) to the terminal apparatus, wherein
• the RA-RNTI is determined at least based on:
• a time-resource unit index that identifies, from a plurality of time-resource units, a first time-resource unit in which the PRACH starts,
• an Orthogonal Frequency-Division Multiplexing (OFDM) index of an OFDM symbol at which the PRACH starts in the first time-resource unit, and
• a number of different possible OFDM symbols at which the PRACH is permitted to start in the first time-resource unit.

A communication method of a terminal apparatus, the communication method comprising:

• transmitting a random access preamble on a Physical Random Access Channel (PRACH) to a base station apparatus;
• and
• receiving downlink control information with Cyclic Redundancy Check (CRC) parity bits scrambled by a Random Access-Radio Network Temporary Identifier (RA-RNTI) from the base station apparatus, wherein
• the RA-RNTI is determined at least based on:
• a time-resource unit index that identifies, from a plurality of time-resource units, a first time-resource unit in which the PRACH starts,
• an Orthogonal Frequency-Division Multiplexing (OFDM) index of an OFDM symbol at which the PRACH starts in the first time-resource unit, and
• a number of different possible OFDM symbols at which the PRACH is permitted to start in the first time-resource unit, and
• the random access preamble on the PRACH is transmitted based on a PRACH mask index included in a Physical Downlink Control Channel (PDCCH) order.

A communication method of a base station apparatus, the communication method comprising:

• receiving a random access preamble on a Physical Random Access Channel (PRACH), the random access preamble being transmitted from a terminal apparatus based on a PRACH mask index included in a Physical Downlink Control Channel (PDCCH) order, and
• transmitting downlink control information with Cyclic Redundancy Check (CRC) parity bits scrambled by a Random Access-Radio Network Temporary Identifier(RA-RNTI) to the terminal apparatus, wherein
• the RA-RNTI is determined at least based on:
• a time-resource unit index that identifies, from a plurality of time-resource units, a first time-resource unit in which the PRACH starts,
• an Orthogonal Frequency-Division Multiplexing (OFDM) index of an OFDM symbol at which the PRACH starts in the first time-resource unit, and
• a number of different possible OFDM symbols at which the PRACH is permitted to start in the first time-resource unit.