Conflict avoidance between random access messages and other transmissions
Methods, systems, and devices for wireless communications are described. Interference between random access channel (RACH) transmissions and Industrial Internet of Things (IIoT) transmissions may be avoided with a RACH occasion forbidden mask and a dynamic indication of availability of downlink retransmission resources. A user equipment (UE) may receive an indication of a RACH configuration and a forbidden mask associated with the RACH configuration. The UE may identify, from a set of random access occasions indicated by the RACH configuration, a subset of allowed random access occasions based on the forbidden mask. The UE may transmit a random access message during at least one allowed random access occasion of the subset. Additionally or alternatively, a base station may determine whether one or more transmissions on a component carrier (CC) were successful, and transmit downlink control information (DCI) indicating whether a set of random access occasions are available on the CC.
1 . A method for wireless communication at a user equipment (UE), comprising:
receiving an allocation of a set of resources, on a component carrier, reserved for at least one retransmission of an initial transmission;
indicating or receiving an indication that the initial transmission was successful;
based at least in part on the indication that the initial transmission was successful, receiving downlink control information comprising an indication that a set of random access occasions is available on the component carrier, the set of random access occasions corresponding to at least a portion of the set of resources reserved for the at least one retransmission on the component carrier; and
transmitting a random access message during at least one random access occasion of the set of random access occasions based at least in part on the downlink control information indicating that the set of random access occasions is available.
2 . The method of claim 1 , wherein receiving the downlink control information comprises:
receiving the downlink control information on a second component carrier that is different from the component carrier.
3 . The method of claim 2 , wherein:
the component carrier is associated with communications in a first frequency range; and
the second component carrier is associated with communication in a second frequency range that is different from the first frequency range.
4 . The method of claim 1 , further comprising:
receiving, as part of the downlink control information, an indication of one or more respective component carriers that include the set of random access occasions.
5 . The method of claim 1 , further comprising:
identifying an offset between the downlink control information and a temporally first random access occasion of the set of random access occasions, wherein transmitting the random access message during the at least one random access occasion is based at least in part on the offset.
6 . The method of claim 1 , wherein one or more of the set of resources reserved for the at least one retransmission are configured for semi-persistent scheduled (SPS) or configured grant (CG) communications.
7 . The method of claim 1 , wherein transmission on one or more of the resources reserved for the at least one retransmission does not occur.
8 . A method for wireless communication at a base station, comprising:
allocating a set of resources, on a component carrier, reserved for at least one retransmission of one or more initial transmissions;
determining that the one or more initial transmissions on the component carrier were successful;
based at least in part on the determination that the one or more initial transmissions was successful, transmitting downlink control information comprising an indication that a set of random access occasions is available on the component carrier, the set of random access occasions corresponding to at least a portion of the set of resources reserved for the at least one retransmission on the component carrier; and
receiving, from a user equipment (UE), a random access message during at least one random access occasion of the set of random access occasions based at least in part on the downlink control information indicating that the set of random access occasions is available.
9 . The method of claim 8 , wherein transmitting the downlink control information comprises:
broadcasting, to one or more UEs, the downlink control information on a second component carrier that is different from the component carrier.
10 . The method of claim 9 , wherein:
the component carrier is associated with communications in a first frequency range; and
the second component carrier is associated with communication in a second frequency range that is different from the first frequency range.
11 . The method of claim 8 , further comprising:
transmitting, as part of the downlink control information, an indication of one or more respective component carriers that include the set of random access occasions.
12 . The method of claim 8 , further comprising:
identifying an offset between the downlink control information and a temporally first random access occasion of the set of random access occasions, wherein receiving the random access message during the at least one random access occasion is based at least in part on the offset.
13 . The method of claim 8 , wherein the one or more initial transmissions comprise semi-persistently scheduled communications, configured grant communications, or a combination thereof.
14 . An apparatus for wireless communication at a user equipment (UE), comprising:
a processor; and
a memory coupled with the processor, wherein the memory comprises instructions executable by the processor to cause the apparatus to:
receive an allocation of a set of resources, on a component carrier, reserved for at least one retransmission of an initial transmission;
indicate or receive an indication that the initial transmission was successful;
based at least in part on the indication that the initial transmission was successful, receive downlink control information comprising an indication that a set of random access occasions is available on the component carrier, the set of random access occasions corresponding to at least a portion of the set of resources reserved for the at least one retransmission on the component carrier; and
transmit a random access message during at least one random access occasion of the set of random access occasions based at least in part on the downlink control information indicating that the set of random access occasions is available.
15 . The apparatus of claim 14 , wherein the instructions are further executable by the processor to cause the apparatus to:
receive the downlink control information on a second component carrier that is different from the component carrier.
16 . The apparatus of claim 15 , wherein:
the component carrier is associated with communications in a first frequency range; and
the second component carrier is associated with communication in a second frequency range that is different from the first frequency range.
17 . The apparatus of claim 14 , wherein the instructions are further executable by the processor to cause the apparatus to:
receive, as part of the downlink control information, an indication of one or more respective component carriers that include the set of random access occasions.
18 . The apparatus of claim 14 , wherein the instructions are further executable by the processor to cause the apparatus to:
identify an offset between the downlink control information and a temporally first random access occasion of the set of random access occasions, wherein transmitting the random access message during the at least one random access occasion is based at least in part on the offset.
19 . The apparatus of claim 14 , wherein one or more of the set of resources reserved for the at least one retransmission are configured for semi-persistent scheduled (SPS) or configured grant (CG) communications.
20 . The apparatus of claim 14 , wherein transmission on one or more of the resources reserved for the at least one retransmission does not occur.
21 . An apparatus for wireless communication at a base station, comprising:
a processor; and
a memory coupled with the processor, wherein the memory comprises instructions executable by the processor to cause the apparatus to:
allocate a set of resources, on a component carrier, reserved for at least one retransmission of one or more initial transmissions;
determine that the one or more initial transmissions on the component carrier were successful;
based at least in part on the determination that the one or more initial transmissions was successful, transmit downlink control information comprising an indication that a set of random access occasions is available on the component carrier, the set of random access occasions corresponding to at least a portion of the set of resources reserved for the at least one retransmission on the component carrier; and
receive, from a user equipment (UE), a random access message during at least one random access occasion of the set of random access occasions based at least in part on the downlink control information indicating that the set of random access occasions is available.
22 . The apparatus of claim 21 , wherein the instructions are further executable by the processor to cause the apparatus to:
broadcast, to one or more UEs, the downlink control information on a second component carrier that is different from the component carrier.
23 . The apparatus of claim 22 , wherein:
the component carrier is associated with communications in a first frequency range; and
the second component carrier is associated with communication in a second frequency range that is different from the first frequency range.
24 . The apparatus of claim 21 , wherein the instructions are further executable by the processor to cause the apparatus to:
transmit, as part of the downlink control information, an indication of one or more respective component carriers that include the set of random access occasions.
25 . The apparatus of claim 21 , wherein the instructions are further executable by the processor to cause the apparatus to:
identify an offset between the downlink control information and a temporally first random access occasion of the set of random access occasions, wherein receiving the random access message during the at least one random access occasion is based at least in part on the offset.
26 . The apparatus of claim 21 , wherein the one or more initial transmissions comprise semi-persistently scheduled communications, configured grant communications, or a combination thereof.