Methods and apparatuses for association between random access channel occasions
Disclosed are methods and apparatuses for small data transmission in random access. One embodiment of the subject application provides a method performed by a user equipment, including determining an association among a first random access channel (RACH) occasion (RO), a preamble, and a second RO, and receiving an random access response (RAR) in an Msg2 at least according to the second RO in response to transmitting the preamble in the first RO.
1 . An apparatus, comprising:
a memory; and
a processor coupled to the memory, the processor configured to cause the apparatus to:
determine an association among a first random access channel (RACH) occasion (RO), a preamble, and a second RO, wherein to determine the association among the first RO, the preamble, and the second RO, the processor is configured to cause the apparatus to determine an association between the first RO and the second RO at least according to a synchronization signal block (SSB), wherein the first RO is configured for a first type of user equipment (UE), the second RO is configured for a second type of UE, the apparatus comprises a UE that belongs to the first type of UE, and the second RO is not earlier than the first RO in a time domain; and
receive a random access response (RAR) in an Msg2 at least according to the second RO in response to transmitting the preamble in the first RO.
2 . The apparatus of claim 1 , wherein the Msg2 is scheduled by a Downlink Control Information (DCI) with a scrambling sequence at least according to the second RO.
3 . The apparatus of claim 1 , wherein:
the second RO comprises an RO configured with:
one or more of a lowest frequency domain position, a highest frequency domain position, a predetermined frequency domain position, or a configured frequency domain position; and
a lowest time domain position among at least one RO associated with the SSB among at least one RO for the second type of UE.
4 . The apparatus of claim 1 , wherein to receive the RAR in the Msg2 at least according the second RO, the processor is configured to cause the apparatus to:
determine a random access (RA) response window for the Msg2 at least according to the second RO.
5 . The apparatus of claim 1 , wherein to determine the association among the first RO, the preamble, and the second RO, the processor is configured to cause the apparatus to:
determine the association among the first RO, the preamble, and the second RO periodically in an RO association period, wherein the RO association period is configured by one or more of a UE, a base station (BS), a network, or is predefined.
6 . The apparatus of claim 5 , wherein the RO association period is determined at least according to one or more of a first period or a second period, and wherein the first period is configured for associating the first RO with the SSB, the second period is configured for associating the second RO with the SSB, and wherein the first period is configured by one or more of the UE, the BS, the network, or is predefined.
7 . The apparatus of claim 6 , wherein the first period is equal to the second period multiplied with a first factor, and wherein the first factor is a positive number and is configured by one or more of the UE, the BS, or is predefined.
8 . The apparatus of claim 6 , wherein the RO association period is determined as a larger period between the first period and the second period and multiplied with a second factor, wherein the second factor is a positive number and is configured by one or more of the UE, the BS, or is predefined.
9 . The apparatus of claim 1 , wherein a medium access control (MAC) sub protocol data unit (subPDU) for the RAR is placed after a last MAC subPDU for the second type of UE in the Msg2 and is treated as padding bits by the second type of UE.
10 . The apparatus of claim 1 , wherein a medium access control (MAC) sub protocol data unit (subPDU) for the RAR includes an indicator indicating that the MAC subPDU for the RAR is for the first type of UE, and the MAC subPDU is not identified by the second type of UE.
11 . An apparatus, comprising:
a memory; and
a processor coupled to the memory, the processor configured to cause the apparatus to:
determine an association among a first random access channel (RACH) occasion (RO), a preamble, and a second RO, wherein to determine the first RO for associating with the second RO, the processor is configured to cause the apparatus to determine the first RO for associating with the second RO at least according to a synchronization signal block (SSB), wherein the first RO is configured for a first type of UE, the second RO is configured for a second type of UE, the UE belongs to the second type of UE, and the second RO is not earlier than the first RO in a time domain; and
transmit a random access response (RAR) in an Msg2 at least according to the second RO in response to receiving the preamble in the first RO from a user equipment (UE).
12 . The apparatus of claim 11 , wherein to determine the association among the first RO, the preamble, and the second RO, the processor is configured to cause the apparatus to:
determine the association among the first RO, the preamble, and the second RO at least according to the SSB periodically in an RO association period, wherein the RO association period is configured by one or more of the UE, a base station (BS), a network, or is predefined.
13 . The apparatus of claim 11 , wherein the Msg2 is scheduled by a Downlink Control Information (DCI) with a scrambling sequence at least according to the second RO.
14 . The apparatus of claim 11 , wherein:
the second RO comprises an RO configured with:
one or more of a lowest frequency domain position, a highest frequency domain position, a predetermined frequency domain position, or a configured frequency domain position; and
a lowest time domain position among at least one RO associated with the SSB among at least one RO for the second type of UE.
15 . The apparatus of claim 11 , wherein a medium access control (MAC) sub protocol data unit (subPDU) for the RAR is placed after a last MAC subPDU for the second type of UE in the Msg2 and is treated as padding bits by the second type of UE.
16 . A method, comprising:
determining, by a user equipment (UE), an association among a first random access channel (RACH) occasion (RO), a preamble, and a second RO, wherein determining the association among the first RO, the preamble, and the second RO further comprises determining an association between the first RO and the second RO at least according to a synchronization signal block (SSB), wherein the first RO is configured for a first type of UE, the second RO is configured for a second type of UE, the UE belongs to the first type of UE, and the second RO is not earlier than the first RO in a time domain; and
receiving a random access response (RAR) in an Msg2 at least according to the second RO in response to transmitting the preamble in the first RO.
17 . The method of claim 16 , wherein the Msg2 is scheduled by a Downlink Control Information (DCI) with a scrambling sequence at least according to the second RO.
18 . The method of claim 16 , wherein:
the second RO is an RO configured with a lowest or highest or predetermined or configured frequency domain position and a lowest time domain position among at least one RO associated with the SSB among at least one RO for the second type of UE.
19 . The method of claim 16 , wherein receiving the RAR in the Msg2 at least according the second RO further comprises:
determining a random access (RA) response window for the Msg2 at least according to the second RO.
20 . The method of claim 16 , wherein determining the association among the first RO, the preamble, and the second RO further comprises:
determining the association among the first RO, the preamble, and the second RO periodically in an RO association period, wherein the RO association period is configured by one or more of the UE, a base station (BS), a network, or is predefined.