Method and apparatus for RACH communication with multi subcarrier spacing configuration
A UE, as a part of a RACH communication procedure, may transmit a first sequence within a first set of resources having a first SCS and a second sequence within a second set of resources having a second SCS greater than the first SCS. The second sequence is transmitted with a cyclic prefix greater than inverse of the first SCS divided by a sequence length of the first sequence. The first sequence is a first PRACH preamble. The second sequence may be a second PRACH preamble, an SRS sequence, or DMRS. The UE may repeat the transmission of the first sequence for a first number of times and repeat the transmission of the second sequence for a second number of times independent of the first number.
1. An apparatus for wireless communication at a user equipment (UE), comprising:
a memory; and
at least one processor coupled to the memory and configured to:
transmit, to a base station, as a part of a random access channel (RACH) procedure, a first sequence within a first set of resources having a first subcarrier spacing (SCS 1 ); and
transmit, to the base station, as a part of the RACH procedure, a second sequence within a second set of resources having a second subcarrier spacing (SCS 2 ), the second subcarrier spacing being greater than the first subcarrier spacing, wherein the second sequence is transmitted with a cyclic prefix (CP) greater than (1/SCS 1 )/L S1 , where L S1 is a sequence length of the first sequence.
2. The apparatus of claim 1 , wherein the first sequence is a first physical RACH (PRACH) preamble and the second sequence is a second PRACH preamble.
3. The apparatus of claim 1 , wherein the at least one processor is further configured to receive a random access response in response to the transmission of at least one of the first sequence or the second sequence.
4. The apparatus of claim 1 , wherein 1/SCS 2 , an inverse of the second subcarrier spacing, is greater than (1/SCS 1 )/L S1 .
5. The apparatus of claim 1 , wherein the first sequence and the second sequence are time multiplexed during transmission.
6. The apparatus of claim 1 , wherein the first sequence and the second sequence are transmitted based on two different transmission opportunities that have at least one of a timing offset (TO) or a frequency offset (FO), the two different transmission opportunities being associated with a same RACH procedure.
7. The apparatus of claim 1 , wherein the at least one processor is further configured to receive a first configuration for a first number of repetitions for transmitting the first sequence and a second configuration for a second number of repetitions for transmitting the second sequence, the first configuration and the second configuration being independent of each other.
8. The apparatus of claim 1 , wherein the first sequence is a first physical RACH (PRACH) preamble and the second sequence is a sounding reference signal (SRS) sequence transmitted through an SRS.
9. The apparatus of claim 1 , wherein the at least one processor is further configured to determine a power offset between the transmission of the first sequence and the transmission of the second sequence, wherein the first sequence is transmitted at a first transmission power, and the second sequence is transmitted at a second transmission power, the first transmission power and the second transmission power being based on the determined power offset.
10. The apparatus of claim 1 , wherein the first sequence is a physical RACH (PRACH) preamble and the second sequence is transmitted through a demodulation reference signal (DMRS).
11. The apparatus of claim 1 , wherein the at least one processor is further configured to receive, from the base station, an indication of a configuration for the first sequence and an indication of a configuration for the second sequence.
12. A method of wireless communication at a user equipment (UE), comprising:
transmitting, to a base station, as a part of a random access channel (RACH) procedure, a first sequence within a first set of resources having a first subcarrier spacing (SCS 1 ); and
transmitting, to the base station, as a part of the RACH procedure, a second sequence within a second set of resources having a second subcarrier spacing (SCS 2 ), the second subcarrier spacing being greater than the first subcarrier spacing, wherein the second sequence is transmitted with a cyclic prefix (CP) greater than (1/SCS 1 )/L S1 , where L S1 is a sequence length of the first sequence.
13. The method of claim 12 , further comprising:
receiving, from the base station, an indication of a configuration for the first sequence and an indication of a configuration for the second sequence.
14. An apparatus for wireless communication at a base station, comprising:
a memory; and
at least one processor coupled to the memory and configured to:
receive, from a user equipment (UE), as a part of a random access channel (RACH) procedure, a first sequence within a first set of resources having a first subcarrier spacing (SCS 1 ); and
receive, from the UE, as a part of the RACH procedure, a second sequence within a second set of resources having a second subcarrier spacing (SCS 2 ), the second subcarrier spacing being greater than the first subcarrier spacing, wherein the second sequence is received with a cyclic prefix (CP) greater than (1/SCS 1 )/L S1 , where L S1 is a sequence length of the first sequence.
15. The apparatus of claim 14 , wherein the at least one processor is further configured to:
configure the first sequence within the first set of resources having the first subcarrier spacing (SCS 1 ); and
configure the second sequence within the second set of resources having the second subcarrier spacing (SCS 2 ), the second subcarrier spacing being greater than the first subcarrier spacing.
16. The apparatus of claim 15 , wherein the at least one processor is further configured to transmit, to the UE, an indication of the configuration for the first sequence and an indication of the configuration for the second sequence.
17. The apparatus of claim 14 , wherein the first sequence is a first physical RACH (PRACH) preamble and the second sequence is a second PRACH preamble.
18. The apparatus of claim 14 , wherein the at least one processor is further configured to transmit, to the UE, a random access response in response to the reception of at least one of the first sequence or the second sequence.
19. The apparatus of claim 14 , wherein 1/SCS 2 , an inverse of the second subcarrier spacing, is greater than (1/SCS 1 )/L S1 .
20. The apparatus of claim 14 , wherein the first sequence and the second sequence are time multiplexed during reception.
21. The apparatus of claim 14 , wherein the first sequence and the second sequence are received based on two different reception opportunities that have at least one of a timing offset (TO) or a frequency offset (FO), the two different reception opportunities being associated with a same RACH procedure.
22. The apparatus of claim 14 , wherein the at least one processor is further configured to transmit, to the UE, a first configuration for a first number of repetitions for transmissions of the first sequence and a second configuration for a second number of repetitions for transmissions of the second sequence, the first configuration and the second configuration being independent of each other.
23. The apparatus of claim 14 , wherein the first sequence is a first physical RACH (PRACH) preamble and the second sequence is a sounding reference signal (SRS) sequence received through an SRS.
24. The apparatus of claim 14 , wherein the at least one processor is further configured to determine that the first sequence and the second sequence have a quasi co-located (QCL) relationship based on a spatial receive (Rx) parameter, wherein the first sequence and the second sequence are received based on the QCL relationship indicating the spatial Rx parameter.
25. The apparatus of claim 14 , wherein the first sequence is a physical RACH (PRACH) preamble and the second sequence is received through a demodulation reference signal (DMRS).
26. A method of wireless communication at a base station, comprising:
receiving, from a user equipment (UE), as a part of a random access channel (RACH) procedure, a first sequence within a first set of resources having a first subcarrier spacing (SCS 1 ); and
receiving, from the UE, as a part of the RACH procedure, a second sequence within a second set of resources having a second subcarrier spacing (SCS 2 ), the second subcarrier spacing being greater than the first subcarrier spacing, wherein the second sequence is received with a cyclic prefix (CP) greater than (1/SCS 1 )/L S1 , where L S1 is a sequence length of the first sequence.
27. The method of claim 26 , further comprising:
configuring the first sequence within the first set of resources having the first subcarrier spacing (SCS 1 ); and
configuring the second sequence within the second set of resources having the second subcarrier spacing (SCS 2 ), the second subcarrier spacing being greater than the first subcarrier spacing.
28. The method of claim 27 , further comprising:
transmitting, to the UE, an indication of the configuration for the first sequence and an indication of the configuration for the second sequence.