Method and apparatus for communication based on short transmission time intervals in wireless communication system

A user equipment (UE) comprising:

• a transceiver configured to:
• receive first information from a base station in a higher layer signaling;
• and
• receive second information from the base station in a DCI (Downlink Control Information) format;
• and
• a controller configured to determine, based on the first information, whether to transmit at least one second DMRS(s) (Demodulation Reference Signal(s)) for PUSCH (Physical Uplink Shared Channel) in addition to a first DMRS for PUSCH,
• wherein the first DMRS is transmitted regardless of the first information and the second information, and
• wherein the first information provides a group of more than one candidates of at least one symbol(s) at second position(s) within a scheduling unit in a case where the at least one second DMRS(s) is to be transmitted,
• wherein the controller is configured to, in the case where the at least one second DMRS(s) is to be transmitted, control the transceiver to transmit the first DMRS and the at least one second DMRS(s), the first DMRS being transmitted at a first position within the scheduling unit and the at least one second DMRS(s) being transmitted at the second position(s) within the scheduling unit,
• wherein the second position(s) is determined, based on the second information, from among the more than one candidates, and
• wherein the controller is configured to, in a case where the at least one second DMRS(s) is not to be transmitted, control the transceiver to transmit the first DMRS without the at least one second DMRS(s) being transmitted within the scheduling unit.

A method of a base station, the method comprising:

• transmitting first information to a User Equipment (UE) in a higher layer signaling;
• transmitting second information to the UE in a DCI (Downlink Control Information) format;
• wherein, whether at least one second DMRS(s) (Demodulation Reference Signal(s)) for PUSCH (Physical Uplink Shared Channel), in addition to a first DMRS for PUSCH, is to be received corresponds to the first information,
• wherein the first DMRS is to be received regardless of the first information and the second information, and
• wherein the first information provides a group of more than one candidates of at least one symbol(s) at second position(s) within a scheduling unit in a case where the at least one second DMRS(s) is to be received;
• in the case where the at least one second DMRS(s) is to be received, receiving the first DMRS and the at least one second DMRS(s), the first DMRS being received at a first position within the scheduling unit and the at least one second DMRS(s) being received at the second position(s) within the scheduling unit,
• wherein the second position(s) is determined, based on the second information, from among the more than one candidates;
• and
• in a case where the at least one second DMRS(s) is not to be received, receiving the first DMRS without the at least one second DMRS(s) being received within the scheduling unit.