METHODS AND APPARATUSES FOR RECEIVING AND TRANSMITTING RANDOM ACCESS RESPONSE IN 2-STEP RANDOM ACCESS

1 . A terminal apparatus comprising:

a transmitter configured to transmit a random access preamble and a physical uplink shard channel corresponding to the random access preamble;

processor circuitry configured to:

determine a first RNTI (Radio Network Temporary Identifier),

control to start a monitoring window from a symbol after a slot or a symbol where the physical uplink shard channel is located; and

control a position of the monitoring window to be not change even when the transmitter transmits the random access preamble without transmitting the physical uplink shard channel, and

a receiver configured to:

detect, within the monitoring window, downlink control information using the first RNTI, the downlink control information scheduling a random access response, and

receive the random access response according to the downlink control information.

2 . The terminal apparatus according to claim 1 , wherein

the receiver is further configured to receive the random access response via a physical downlink shared channel.

3 . The terminal apparatus according to claim 1 , wherein

the first RNTI is different from an RA-RNTI (Random Access-Radio Network Temporary Identity) calculated in a 4-step random access.

4 . The terminal apparatus according to claim 1 , wherein

the first RNTI is an RA-RNTI (Random Access-Radio Network Temporary Identity) calculated in a 2-step random access.

5 . The terminal apparatus according to claim 3 , wherein

the processor circuitry is further configured to determine the first RNTI according to a second RNTI and an offset, the second RNTI is a RNTI according to the random access preamble.

6 . The terminal apparatus according to claim 5 , wherein

the offset is equal to or greater than the maximum of all possible values of the RNTI.

7 . The terminal apparatus according to claim 5 , wherein

the offset is greater than or equal to one of the following values:

a maximum value of all possible values of the RA-RNTI satisfying a condition that an index of an uplink carrier used in transmitting a preamble is zero;

a maximum value of all possible values of the RA-RNTI satisfying a condition that an index of a frequency resource where a PRACH occasion (RO) is located is equal to an index of a frequency resource to which a maximum RA-RNTI that is actually used corresponds; or

a maximum RA-RNTI that is actually used.

8 . The terminal apparatus according to claim 5 , wherein

the second RNTI is determined according to an index of a first symbol where a PRACH occasion (RO) of a 2-step random access is located, an index of a first slot where the RO of the 2-step random access is located in a system frame, an index of a frequency resource where the RO of the 2-step random access is located, and an index of an uplink carrier used in transmitting a preamble.

9 . The terminal apparatus according to claim 5 , wherein

the offset is configured by a network device via at least one of the following:

a broadcast message;

RRC signaling; or

an MAC control element (MAC CE).

10 . A network apparatus comprising:

a receiver configured to receive a random access preamble and a physical uplink shard channel corresponding to the random access preamble; and

a transmitter configured to:

transmit, within a monitoring window from a symbol after a slot or a symbol where the physical uplink shard channel is located, downlink control information using a first RNTI, the downlink control information scheduling a random access response, and

transmit the random access response according to the downlink control information, wherein

a position of the monitoring window to be not change even when the receiver receives the random access preamble without receiving the physical uplink shard channel.

11 . The network apparatus according to claim 10 , wherein

the transmitter is further configured to transmit the random access response via a physical downlink shared channel.

12 . The network apparatus according to claim 10 , wherein

the first RNTI is different from an RA-RNTI (Random Access-Radio Network Temporary Identity) calculated in a 4-step random access.

13 . The network apparatus according to claim 10 , wherein

the first RNTI is an RA-RNTI (Random Access-Radio Network Temporary Identity) calculated in a 2-step random access.

14 . The network apparatus according to claim 13 , wherein

processor circuitry is further configured to determine the first RNTI according to a second RNTI and an offset, the second RNTI is a RNTI according to the random access preamble.

15 . The network apparatus according to claim 14 , wherein

the offset is equal to or greater than the maximum of all possible values of the RNTI.

16 . The network apparatus according to claim 14 , wherein

the transmitter is further configured to transmit information of the offset via a broadcast message, RRC signaling, or an MAC control element (MAC CE).

17 . A communication system comprising:

a terminal apparatus configured to:

transmit a random access preamble and a physical uplink shard channel corresponding to the random access preamble,

determine a first RNTI (Radio Network Temporary Identifier),

control to start a monitoring window from a symbol after a slot or a symbol where the physical uplink shard channel is located,

detect, within the monitoring window, downlink control information using the first RNTI, the downlink control information scheduling a random access response, and

receive the random access response according to the downlink control information; and

a network device configured to:

receive the random access preamble and the physical uplink shard channel,

transmit the downlink control information, and

transmit the random access response, wherein

the terminal apparatus is further configured to control a position of the monitoring window to be not change even when the transmitter transmits the random access preamble without transmitting the physical uplink shard channel.