Random access response message repetition
Aspects relate to random access procedures. A base station may transmit a random access response message to a user equipment (UE) on a downlink control channel at a first monitoring occasion and transmit at least one repetition of the random access message at at least one offset from the first monitoring occasion. The base station may also transmit an indication of the offset(s) to the UE. Upon receiving the indication of the offset(s), the UE may monitor for the random access response message on the downlink control channel at the first monitoring occasion and at the monitoring occasion(s) for the repetition(s). A UE may identify a first radio network temporary identifier (RNTI) used to affect a physical downlink control channel (PDCCH) sent within a random access response (RAR) window and determine based on the first RNTI that the PDCCH is one of a plurality of PDCCH repetitions.
1. A user equipment, comprising:
a transceiver;
one or more memories storing processor-executable code; and
one or more processors configured to execute the processor-executable code to cause the user equipment to:
receive a first random access time offset value and a second random access time offset value from a base station via the transceiver;
receive a first random access response physical downlink control channel (PDCCH) message from the base station via the transceiver during a monitoring occasion;
receive a second random access response PDCCH message from the base station via the transceiver at a first time that is offset from the monitoring occasion by the first random access time offset value; and
receive a third random access response PDCCH message from the base station via the transceiver at a second time that is offset from the monitoring occasion by the second random access time offset value.
2. The user equipment of claim 1 , wherein the one or more processors are further configured to execute the processor-executable code to cause the user equipment to:
soft combine the first random access response PDCCH message, the second random access response PDCCH message, and the third random access response PDCCH message.
3. The user equipment of claim 1 , wherein each of the first random access response PDCCH message, the second random access response PDCCH message, and the third random access response PDCCH message is a control channel portion of a message 2 of a random access channel (RACH) procedure.
4. The user equipment of claim 1 , wherein the second random access response PDCCH message precedes the first random access response PDCCH message by the first random access time offset value.
5. The user equipment of claim 1 , wherein the second random access response PDCCH message follows the first random access response PDCCH message by the first random access time offset value.
6. The user equipment of claim 1 , wherein:
the first random access response PDCCH message is in a first slot; and
the second random access response PDCCH message is in a second slot.
7. The user equipment of claim 6 , wherein the first slot immediately follows the second slot.
8. The user equipment of claim 6 , wherein there is at least one intervening slot between the first slot and the second slot.
9. The user equipment of claim 1 , wherein the one or more processors are further configured to execute the processor-executable code to cause the user equipment to:
jointly decode the first random access response PDCCH message, the second random access response PDCCH message, and the third random access response PDCCH message.
10. The user equipment of claim 9 , wherein:
the second random access response PDCCH message precedes the first random access response PDCCH message by the first random access time offset value; and
the third random access response PDCCH message follows the first random access response PDCCH message by the second random access time offset value.
11. The user equipment of claim 9 , wherein:
the first random access response PDCCH message and the third random access response PDCCH message are in a first slot; and
the second random access response PDCCH message is in a second slot that precedes the first slot.
12. The user equipment of claim 11 , wherein the second slot immediately precedes the first slot.
13. The user equipment of claim 9 , wherein:
the first random access response PDCCH message is in a first slot;
the second random access response PDCCH message is in a second slot; and
the third random access response PDCCH message is in a third slot.
14. The user equipment of claim 1 , wherein the one or more processors are further configured to execute the processor-executable code to cause the user equipment to:
receive remaining minimum system information that includes the first random access time offset value and the second random access time offset value.
15. The user equipment of claim 1 , wherein the first random access time offset value indicates how many orthogonal frequency division multiplexing (OFDM) symbols separate the first random access response PDCCH message and the second random access response PDCCH message.
16. The user equipment of claim 1 , wherein the one or more processors are further configured to execute the processor-executable code to cause the user equipment to:
determine timing of a physical downlink shared channel from a time of the monitoring occasion and an offset parameter indicated by downlink control information received from the base station.
17. The user equipment of claim 1 , wherein the one or more processors are further configured to execute the processor-executable code to cause the user equipment to:
determine that decoding of a random access response message failed;
transmit a first indication that the decoding of the random access response message failed to the base station; and
receive a second indication from the base station after transmitting the first indication, wherein the second indication specifies that the random access time offset value and the second random access time offset value are to be used for receiving random access response PDCCH messages from the base station.
18. A method for wireless communication at a user equipment, the method comprising:
receiving a first random access time offset value and a second random access time offset value from a base station;
receiving a first random access response physical downlink control channel (PDCCH) message from the base station during a monitoring occasion;
receiving a second random access response PDCCH message from the base station at a first time that is offset from the monitoring occasion by the first random access time offset value; and
receive a third random access response PDCCH message from the base station at a second time that is offset from the monitoring occasion by the second random access time offset value.
19. The method of claim 18 , further comprising:
soft combining the first random access response PDCCH message, the second random access response PDCCH message, and the third random access response PDCCH message.
20. The method of claim 18 , wherein each of the first random access response PDCCH message, the second random access response PDCCH message, and the third random access response PDCCH message is a control channel portion of a message 2 of a random access channel (RACH) procedure.
21. The method of claim 18 , wherein the second random access response PDCCH message precedes the first random access response PDCCH message by the first random access time offset value.
22. The method of claim 18 , wherein the second random access response PDCCH message follows the first random access response PDCCH message by the first random access time offset value.
23. The method of claim 18 , wherein:
the first random access response PDCCH message is in a first slot; and
the second random access response PDCCH message is in a second slot.
24. The method of claim 23 , wherein the first slot immediately follows the second slot.
25. The method of claim 23 , wherein there is at least one intervening slot between the first slot and the second slot.
26. The method of claim 18 , further comprising:
jointly decoding the first random access response PDCCH message, the second random access response PDCCH message, and the third random access response PDCCH message.
27. The method of claim 26 , wherein:
the second random access response PDCCH message precedes the first random access response PDCCH message by the first random access time offset value; and
the third random access response PDCCH message follows the first random access response PDCCH message by the second random access time offset value.
28. The method of claim 26 , wherein:
the first random access response PDCCH message and the third random access response PDCCH message are in a first slot; and
the second random access response PDCCH message is in a second slot that precedes the first slot.
29. The method of claim 28 , wherein the second slot immediately precedes the first slot.
30. A user equipment, comprising:
means for a first random access time offset value and a second random access time offset value from a base station;
means for receiving a first random access response physical downlink control channel (PDCCH) message from the base station during a monitoring occasion;
means for receiving a second random access response PDCCH message from the base station at a first time that is offset from the monitoring occasion by the first random access time offset value; and
means for receive a third random access response PDCCH message from the base station at a second time that is offset from the monitoring occasion by the second random access time offset value.