Transmission and reception device and method for performing random access
In the present invention, a terminal can appropriately perform a random-access process. In a terminal ( 100 ), a wireless transmission unit ( 111 ) transmits a random-access signal including at least a data part. A rank determination unit ( 107 ) controls the configuration of the data part on the basis of a parameter regarding the transmission of the random-access signal.
1. A communication apparatus comprising:
a transmitter; and
circuitry, which, in operation, determines, based on a Random Access Channel (RACH) type, a number of ports used for a data part of a Message A transmission in 2-step random access procedure, and
in a first case that the determined RACH type is Contention Base Random Access (CBRA),
the circuitry selects a random access preambles group from a first random access preambles group or a second random access preambles group based on pathloss measured by the communication apparatus, each of the random access preambles groups being configured with one or more parameters including the number of ports used for the data part of the Message A transmission, respectively, and further selects, randomly, a random access preamble from the selected preamble groups, and
the transmitter transmits the selected random access preamble and the data part simultaneously in the Message A transmission using the number of ports configured for the selected random access preamble group, and
in a second case that the determined RACH type is Contention Free Random Access (CFRA),
the circuitry determines the number of ports used for the data part of the Message A transmission based on a received control information, and
the transmitter transmits a random access preamble and the data part simultaneously in the Message A transmission using the number of ports indicated by the control information.
2. The communication apparatus according to claim 1 , wherein the one or more parameters include a demodulation reference signal configuration.
3. The communication apparatus according to claim 1 , wherein the random access preambles group is selected, based on a data size of the data part of the Message A.
4. A communication method comprising:
determining, based on a Random Access Channel (RACH) type, a number of ports used for a data part of a Message A transmission in 2-step random access procedure;
in a first case that the determined RACH type is Contention Base Random Access (CBRA),
selecting a random access preambles group from a first random access preambles group or a second random access preambles group based on pathloss measured by the communication apparatus, each of random access preambles group being configured with one or more parameters including the number of ports used for the data part of the Message A transmission, respectively, and further selecting, randomly, a random access preamble from the selected preamble groups; and
transmitting the selected random access preamble and the data part simultaneously in the Message A transmission using the number of ports configured for the selected random access preamble group; and
in a second case that the determined RACH type is Contention Free Random Access (CFRA);
determining the number of ports used for the data part of the Message A transmission based on a received control information; and
transmitting a random access preamble and the data part simultaneously in the Message A transmission using the number of ports indicated by the control information.
5. The communication method according to claim 4 , wherein the one or more parameters include a demodulation reference signal configuration.
6. The communication method according to claim 4 , wherein the random access preambles group is selected, based on a data size of the data part of the Message A.
7. The communication apparatus according to claim 1 , wherein the circuitry, in operation, selects the random access preambles group based on whether the pathloss measured by the communication apparatus is less than a threshold which is specified by higher layer signaling.