On collision handling of MsgA PUSCH in 2-step RACH and other uplink channels
A method and device are disclosed for performing collision resolution in a two-step random access channel (RACH) process. In such a process, an MsgA PUSCH signal and a grant based PUSCH signal may collide. When such a collision is detected, either the MsgA PUSCH signal or the grant based PUSCh signal are dropped. The other of the two signals is then transmitted. The determination regarding which signal to drop can be based on a set of rules stored in memory.
1. A method for performing a random access channel (RACH) process between a user equipment (UE) and an access node, the method comprising:
first determining that transmission of an MsgA Physical Uplink Shared Channel (PUSCH) signal of the RACH will collide with a configured grant PUSCH transmission, wherein the RACH has higher priority than the configured grant PUSCH;
second determining that the RACH was triggered by a System Information (S1) request;
in response to the second determining, dropping the MsgA PUSCH signal until a next available transmission opportunity;
wherein the dropping is governed by a set of predefined rules stored at the UE; and
transmitting the configured grant PUSCH in response to the dropping.
2. The method of claim 1 , wherein the MsgA PUSCH signal and the configured grant PUSCH transmission collide when they overlap in a given component carrier in time.
3. The method of claim 1 , wherein the dropping includes, based on the set of predefined rules:
third determining the configured grant PUSCH is used to carry high priority logical channels; and
in response to the third determining, dropping the MsgA PUSCH signal until the next available transmission opportunity.
4. The method of claim 1 , wherein the set of predefined rules depends on an uplink control information (UCI) type or transmission duration of physical channels.
5. A user equipment, comprising:
a memory that stores a set of predefined rules governing signal priority in a collision scenario;
a processor configured to:
first determine that transmission of an MsgA Physical Uplink Shared Channel (PUSCH) signal of a random access channel (RACH) will collide with a configured grant PUSCH transmission, wherein the RACH has higher priority than the configured grant PUSCH;
second determine that the RACH was triggered by a System Information (SI) request; and
in response to the second determination, drop the MsgA PUSCH signal until a next available transmission opportunity;
and
a transmitter configured to transmit the configured grant PUSCH in response to the dropping.
6. The user equipment of claim 5 , wherein the MsgA PUSCH signal and the configured grant PUSCH transmission collide when they overlap in a given component carrier in time.
7. The user equipment of claim 5 , wherein the processor is further configured to determine whether the configured grant PUSCH is used to carry high priority logic channels; and
wherein the dropping includes dropping, based on the set of predefined rules, the MsgA PUSCH signal until the next available transmission opportunity in response to the determining the configured grant PUSCH is used to carry high priority logic channels.
8. The user equipment of claim 7 , wherein the set of predefined rules depends on an uplink control information (UCI) type or transmission duration of physical channels.
9. The user equipment of claim 8 , wherein the dropping is based on a priority of the UCI type in an order of hybrid automatic repeat request-acknowledgement (HARQ-ACK) feedback, scheduling request (SR), channel state information (CSI) report with higher priority, and CSI report with lower priority.