Variable length downlink control information formats for next generation radio technologies

An integrated circuit (IC) comprising:

• circuitry configured to instruct transmission of a first message of a two-step random access procedure;
• circuitry configured to receive higher layer signaling;
• circuitry configured to receive first downlink control information (DCI), of a first DCI format, on a physical downlink control channel (PDCCH);
• circuitry configured to receive second DCI, of a second DCI format, on the PDCCH, wherein the second DCI format is different than the first DCI format and the second DCI format includes fixed length fields and variable length fields, wherein the variable length fields of the second DCI format include a frequency resource parameter, a priority indicator, at least one hybrid automatic repeat request (HARQ) parameter, a bandwidth part indicator, a demodulation reference signal (DMRS) sequence initialization, redundancy information and a carrier indicator;
• wherein the fixed length fields of the second DCI format include a modulation and coding scheme (MCS) index and a transmit power control (TPC) command;
• circuitry configured to receive third DCI, of a third DCI format, wherein the third DCI format is different than the first DCI format and the third DCI format includes a variable number of variable length fields, each one of the variable length fields of the third DCI format indicating cancellation of a scheduled transmission;
• circuitry configured to determine at least one time domain transmission parameter, based on the second DCI and the higher layer signaling;
• wherein a total number of data bits of the second DCI is less than a total number of data bits of the first DCI.

A base station (BS) comprising:

• a receiver configured to receive a first message of a two-step random access procedure;
• a transmitter configured to transmit higher layer signaling;
• the transmitter further configured to transmit first downlink control information (DCI), of a first DCI format, on a physical downlink control channel (PDCCH);
• the transmitter further configured to transmit second DCI, of a second DCI format, on the PDCCH, wherein the second DCI format is different than the first DCI format and the second DCI format includes fixed length fields and variable length fields, wherein the variable length fields of the second DCI format include a frequency resource parameter, a priority indicator, at least one hybrid automatic repeat request (HARQ) parameter, a bandwidth part indicator, a demodulation reference signal (DMRS) sequence initialization, redundancy information, a carrier indicator and a number of layers;
• wherein the fixed length fields of the second DCI format include a modulation and coding scheme (MCS) index and a transmit power control (TPC) command;
• the transmitter further configured to transmit third DCI, of a third DCI format, wherein the third DCI format is different than the first DCI format and the third DCI format includes a variable number of variable length fields, each one of the variable length fields of the third DCI format indicating cancellation of a scheduled transmission;
• and
• circuitry configured to indicate at least one time domain transmission parameter, via the second DCI and the higher layer signaling;
• wherein a total number of data bits of the second DCI is less than a total number of data bits of the first DCI.