Terminal device, base station device, and communication method

A base station device configured to communicate with a terminal device, the base station device comprising:

• transmission circuitry configured to transmit an enhanced physical downlink control channel (EPDCCH) on a Serving cell having a frame structure type 3 which is used for a Licensed Assisted Access (LAA) cell, wherein
• the LAA cell including a plurality of subframes which are numbered serially,
• the subframes being designated as one of a plurality of special subframe configurations 0 to 9,
• a number of enhanced resource element groups (EREGs) included in an enhanced control channel element (ECCE) being determined by the special subframe configurations,
• in a case that the terminal device detects downlink control information (DCI) in a first subframe which is one of the numbered subframes, the terminal device assumes a configuration of Orthogonal Frequency Division Multiplexing (OFDM) symbols according to a field in the DCI in the first subframe,
• the OFDM symbols are used for downlink transmission,
• information mapped in the first subframe indicates a number of first OFDM symbols, which are used for the downlink transmission, in a second subframe which is another one of the numbered subframes and subsequent to the first subframe, and
• a demodulation reference signal (DMRS) associated with the EPDCCH is mapped in the first subframe according to the configuration of OFDM symbols.

A communication method of a terminal device configured to communicate with a base station device, the communication method comprising the step of:

• monitoring an enhanced physical downlink control channel (EPDCCH) on a Serving cell having a frame structure type 3 which is used for a Licensed Assisted Access (LAA) cell, wherein
• the LAA cell including a plurality of subframes which are numbered serially,
• the subframes being designated as one of a plurality of special subframe configurations 0 to 9,
• a number of enhanced resource element groups (EREGs) included in an enhanced control channel element (ECCE) being determined by the special subframe configurations,
• in a case that the terminal device detects downlink control information (DCI) in a first subframe which is one of the numbered subframes, the terminal device assumes a configuration of Orthogonal Frequency Division Multiplexing (OFDM) symbols according to a field in the DCI in the first subframe,
• the OFDM symbols are used for downlink transmission,
• information mapped in the first subframe indicates a number of first OFDM symbols, which are used for the downlink transmission, in a second subframe which is another one of the numbered subframes and subsequent to the first subframe, and
• a demodulation reference signal (DMRS) associated with the EPDCCH is mapped in the first subframe according to the configuration of the OFDM symbols.

A communication method of a base station device configured to communicate with a terminal device, the communication method comprising the step of:

• transmitting an enhanced physical downlink control channel (EPDCCH) on a Serving cell having a frame structure type 3 which is used for a Licensed Assisted Access (LAA) cell, wherein
• the LAA cell including a plurality of subframes which are numbered serially,
• the subframes being designated as one of a plurality of special subframe configurations 0 to 9,
• a number of enhanced resource element groups (EREGs) included in an enhanced control channel element (ECCE) being determined by the special subframe configurations,
• in a case that the terminal device detects downlink control information (DCI) in a first subframe which is one of the numbered subframes, the terminal device assumes a configuration of Orthogonal Frequency Division Multiplexing (OFDM) symbols according to a field in the DCI in the first subframe,
• the OFDM symbols are used for downlink transmission,
• information mapped in the first subframe indicates a number of first OFDM symbols, which are used for the downlink transmission, in a second subframe which is another one of the numbered subframes and subsequent to the first subframe, and
• a demodulation reference signal (DMRS) associated with the EPDCCH is mapped in the first subframe according to the configuration of the OFDM symbols.