Random access procedure timing designs
A configurable new radio (NR) RACH procedure that may be executed by a UE and a base station is disclosed. A first message can be transmitted, in an inactive or idle state, a on a physical random access channel, where the first message includes a random access preamble. A second message can be received on a downlink channel in response to the first message, where the second message includes a temporary cell radio network temporary identifier and an uplink grant for the user equipment. A request can be transmitted on an uplink channel based on the uplink grant. A common search space of a downlink control channel can be monitored, such as for an acknowledgement message or a negative acknowledgement message corresponding to the request and identifiable based on the temporary cell radio network temporary identifier.
1. A method of wireless communications, comprising:
receiving, by a user equipment, a configuration to determine a random access procedure timeline of a use case or a deployment, from multiple random access procedure timelines that each define a different duration between one or more messages that are communicated in a random access procedure;
transmitting, by the user equipment, a first message on a physical random access channel, wherein the first message includes a random access preamble;
receiving, by the user equipment and based on the random access procedure timeline, a second message on a downlink channel in response to the first message, wherein the second message includes an uplink grant for the user equipment;
transmitting, by the user equipment and based on the random access procedure timeline, a request or indicator on an uplink channel based on the uplink grant; and
monitoring, by the user equipment, a downlink control channel for an acknowledgement message or a negative acknowledgement message corresponding to the request or indicator.
2. The method of claim 1 ,
the configuration being further to determine a second random access procedure timeline of a second use case or deployment.
3. The method of claim 2 , further comprising:
monitoring, by the user equipment, in a window of the second random access procedure timeline and after transmitting a second request or indicator, acknowledgement of the second request or indicator.
4. The method of claim 3 , further comprising:
retransmitting, by the user equipment, the second request or indicator after the window responsive to not receiving acknowledgement in the window, without a second uplink grant after the window.
5. The method of claim 1 , wherein the second message further includes a temporary cell radio network temporary identifier and wherein the acknowledgement message or the negative acknowledgement message corresponding to the request or indicator is identifiable based on the temporary cell radio network temporary identifier.
6. The method of claim 1 , wherein transmitting the first message includes transmitting, by the user equipment in an inactive or idle state, the first message on the physical random access channel.
7. The method of claim 1 , the request or indicator being associated with a trigger event of the random access procedure.
8. An apparatus for wireless communication, comprising:
a transceiver;
a memory configured to store instructions; and
one or more processors communicatively coupled with the memory and the transceiver, wherein the one or more processors are configured to execute the instructions to cause the apparatus to:
receive a configuration to determine a random access procedure timeline of a use case or a deployment, from multiple random access procedure timelines that each define a different duration between one or more messages that are communicated in a random access procedure;
transmit a first message on a physical random access channel, wherein the first message includes a random access preamble;
receive, based on the random access procedure timeline, a second message on a downlink channel in response to the first message, wherein the second message includes an uplink grant for the apparatus;
transmit, based on the random access procedure timeline, a request or indicator on an uplink channel based on the uplink grant; and
monitor a downlink control channel for an acknowledgement message or a negative acknowledgement message corresponding to the request or indicator.
9. The apparatus of claim 8 , the configuration being further to determine a second random access procedure timeline of a second use case or deployment.
10. The apparatus of claim 9 , wherein the one or more processors are further configured to execute the instructions to cause the apparatus to monitor, in a window of the second random access procedure timeline and after transmitting a second request or indicator, acknowledgement of the second request or indicator.
11. The apparatus of claim 10 , wherein the one or more processors are further configured to execute the instructions to cause the apparatus to retransmit the second request or indicator after the window responsive to not receiving acknowledgement in the window, without a second uplink grant after the window.
12. The apparatus of claim 8 , wherein the second message further includes a temporary cell radio network temporary identifier and wherein the acknowledgement message or the negative acknowledgement message corresponding to the request or indicator is identifiable based on the temporary cell radio network temporary identifier.
13. The apparatus of claim 8 , wherein the one or more processors are configured to execute the instructions to cause the apparatus to transmit the first message including transmitting, in an inactive or idle state, the first message on the physical random access channel.
14. The apparatus of claim 8 , the request or indicator being associated with a trigger event of the random access procedure.
15. A non-transitory computer-readable medium, comprising code executable by one or more processors for wireless communications, the code comprising code for:
receiving, by a user equipment, a configuration to determine a random access procedure timeline of a use case or a deployment, from multiple random access procedure timelines that each define a different duration between one or more messages that are communicated in a random access procedure;
transmitting, by the user equipment, a first message on a physical random access channel, wherein the first message includes a random access preamble;
receiving, by the user equipment and based on the random access procedure timeline, a second message on a downlink channel in response to the first message, wherein the second message includes an uplink grant for the user equipment;
transmitting, by the user equipment and based on the random access procedure timeline, a request or indicator on an uplink channel based on the uplink grant; and
monitoring, by the user equipment, a downlink control channel for an acknowledgement message or a negative acknowledgement message corresponding to the request or indicator.
16. The non-transitory computer-readable medium of claim 15 , the configuration being further to determine a second random access procedure timeline of a second use case or deployment.
17. The non-transitory computer-readable medium of claim 16 , further comprising code for monitoring, by the user equipment, in a window of the second random access procedure timeline and after transmitting a second request or indicator, acknowledgement of the second request or indicator.
18. The non-transitory computer-readable medium of claim 17 , further comprising code for retransmitting, by the user equipment, the second request or indicator after the window responsive to not receiving acknowledgement in the window, without a second uplink grant after the window.
19. The non-transitory computer-readable medium of claim 15 , wherein the second message further includes a temporary cell radio network temporary identifier and wherein the acknowledgement message or the negative acknowledgement message corresponding to the request or indicator is identifiable based on the temporary cell radio network temporary identifier.
20. The non-transitory computer-readable medium of claim 15 , wherein the code for transmitting the first message includes code for transmitting, by the user equipment in an inactive or idle state, the first message on the physical random access channel.