Signaling to indicate locations of dedicated random access channel region in time domain
Methods, systems, and devices for wireless communications are described. A node (e.g., a base station or network entity) may identify a signal that provides an indication of a location of a contention free random access channel (CFRA) resource within a time region and an indication of a timing pattern for the CFRA resource, the timing pattern associated with a pattern of subsequent instances of the time region in which the CFRA resource is repeated, wherein the CFRA resource is not a fully overlapping resource with respect to a contention based random access (CBRA) resource. The node may convey the signal to one or more user equipment (UE) to indicate the location and the timing pattern.
1. A method for wireless communication at a node, comprising:
transmitting, for one or more user equipments (UEs), a signal indicating a location of a contention free random access channel (CFRA) resource within a time region and indicating a number of actually transmitted synchronization signal block (SSB) signals, wherein:
the CFRA resource is based at least in part on the actually transmitted SSB signals and is partially overlapping and not fully overlapping in time with respect to a contention based random access (CBRA) resource,
the signal indicates a timing pattern for the CFRA resource via a symbol index within a radio frame and a system frame number configuration index,
the timing pattern associated with a pattern of subsequent instances of the time region in which the CFRA resource is repeated, and
the signal indicates a physical random access channel (PRACH) configuration index to provide at least one of the location of the CFRA resource, or the indication of the timing pattern for the CFRA resource, or a combination thereof; and
determining the timing pattern based at least in part on the symbol index and the system frame number configuration index; and
receiving, during at least one instance of the CFRA resource within the time region, a random access channel (RACH) transmission using the CFRA resource.
2. The method of claim 1 , wherein the timing pattern comprises an aperiodic pattern.
3. The method of claim 1 , further comprising:
identifying one or more symbols within the time region in which the CFRA resource will occur, wherein the location is based at least in part on the one or more symbols.
4. The method of claim 3 , wherein the location comprises a starting symbol of the CFRA resource.
5. The method of claim 1 , further comprising:
identifying a subset of time regions from a set of time regions, each time region within the subset of time regions comprising one or more instances of the CFRA resource, wherein the timing pattern for the CFRA resource is based at least in part on the subset of time regions.
6. The method of claim 1 , wherein:
the signal is transmitted in a first radio frequency spectrum band and the RACH transmission is received in a second radio frequency spectrum band, the second radio frequency spectrum band being different from the first radio frequency spectrum band; or
the signal is transmitted via a first radio access technology (RAT) and the RACH transmission is received via a second RAT, the second RAT being different from the first RAT.
7. The method of claim 1 , wherein the location of the CFRA resource comprises at least one of a symbol within a slot, or a slot within a subframe, or a subframe within a radio frame, or a radio frame within a set of radio frames, or a combination thereof.
8. The method of claim 1 , wherein the CFRA resource is associated with a time-frequency region, and the CFRA resource comprises a RACH occasion.
9. The method of claim 1 , wherein the node comprises a network entity, the method further comprising:
obtaining, by the network entity, the signal from a target cell; and
transmitting, by the network entity, the signal to a serving cell to be relayed to the one or more UEs.
10. The method of claim 1 , wherein the time region comprises at least one of a frame, a subframe, a slot, or a mini-slot.
11. The method of claim 1 , wherein the timing pattern comprises a periodic pattern.
12. The method of claim 1 , wherein the PRACH configuration index indicates a corresponding preamble format, one or more modulus operators for each subframe number associated with the CFRA resource, one or more slot numbers in which a physical random access channel (PRACH) resource is configured, a starting symbol within each slot of the time region, and a number of time domain PRACH occasions that are within a RACH slot.
13. The method of claim 1 , wherein the timing pattern indicates one or more CFRA resources in every radio frame of the time region.
14. A wireless communication node, comprising:
a processor configured to generate a signal indicating a location of a contention free random access channel (CFRA) resource within a time region and indicating a number of actually transmitted synchronization signal block (SSB) signals, wherein:
the CFRA resource is based at least in part on the actually transmitted SSB signals and is partially overlapping and not fully overlapping in time with respect to a contention based random access (CBRA) resource,
the signal indicates a timing pattern for the CFRA resource via a symbol index within a radio frame and a system frame n umber configuration index,
the timing pattern associated with a pattern of subsequent instances of the time region in which the CFRA resource is repeated, and
the signal indicates a physical random access channel (PRACH) configuration index to provide at least one of the location of the CFRA resource, or the indication of the timing pattern for the CFRA resource, or a combination thereof, and
the processor is further configured to determine the timing pattern based at least in part on the symbol index and the system frame number configuration index; and
a transmitter configured to transmit, for one or more user equipments (UEs), the signal to indicate the location, the timing pattern, and the time region; and
a receiver configured to receive, during at least one instance of the CFRA resource within the time region, a random access channel (RACH) transmission using the CFRA resource.
15. The wireless communication node of claim 14 , wherein the timing pattern comprises at least one of a periodic pattern or an aperiodic pattern.
16. The wireless communication node of claim 14 , wherein:
the processor is configured to identify one or more symbols within the time region in which the CFRA resource will occur, wherein the location is based at least in part on the one or more symbols.
17. The wireless communication node of claim 16 , wherein the location comprises a starting symbol of the CFRA resource.
18. The wireless communication node of claim 14 , wherein:
the processor is configured to identify a subset of time regions from a set of time regions, each time region within the subset of time regions comprising one or more instances of the CFRA resource, wherein the timing pattern for the CFRA resource is based at least in part on the subset of time regions.
19. The wireless communication node of claim 14 , wherein:
the signal is transmitted in a first radio frequency spectrum band and the RACH transmission is received in a second radio frequency spectrum band, the second radio frequency spectrum band being different from the first radio frequency spectrum band; or
the signal is transmitted via a first radio access technology (RAT) and the RACH transmission is received via a second RAT, the second RAT being different from the first RAT.
20. The wireless communication node of claim 14 , wherein the location of the CFRA resource comprises at least one of a symbol within a slot, or a slot within a subframe, or a subframe within a radio frame, or a radio frame within a set of radio frames, or a combination thereof.
21. The wireless communication node of claim 14 , wherein the CFRA resource is associated with a time-frequency region, and the CFRA resource comprises a RACH occasion.
22. The wireless communication node of claim 14 , wherein the wireless communication node comprises a network entity, wherein the receiver is configured to receive, by the network entity, the signal from a target cell, and wherein the transmitter is configured to transmit, by the network entity, the signal to a serving cell to be relayed to the one or more UEs.
23. The wireless communication node of claim 14 , wherein the time region comprises at least one of a frame, a subframe, a slot, or a mini-slot.
24. A wireless communication node, comprising:
means for transmitting, for one or more user equipments (UEs), a signal indicating a location of a contention free random access channel (CFRA) resource within a time region and indicating a number of actually transmitted synchronization signal block (SSB) signals, wherein:
the CFRA resource is based at least in part on the actually transmitted SSB signals and is partially overlapping and not fully overlapping in time with respect to a contention based random access (CBRA) resource,
the signal indicates a timing pattern for the CFRA resource via a symbol index within a radio frame and a system frame n umber configuration index,
the timing pattern associated with a pattern of subsequent instances of the time region in which the CFRA resource is repeated, and
the signal indicates a physical random access channel (PRACH) configuration index to provide at least one of the location of the CFRA resource, or the indication of the timing pattern for the CFRA resource, or a combination thereof; and
means for determining the timing pattern based at least in part on the symbol index and the system frame number configuration index; and
means for receiving, during at least one instance of the CFRA resource within the time region, a random access channel (RACH) transmission using the CFRA resource.
25. The wireless communication node of claim 24 , wherein the timing pattern comprises at least one of a periodic pattern or an aperiodic pattern.
26. The wireless communication node of claim 24 , further comprising:
means for identifying one or more symbols within the time region in which the CFRA resource will occur, wherein the location is based at least in part on the one or more symbols.
27. The wireless communication node of claim 24 , further comprising:
means for identifying a subset of time regions from a set of time regions, each time region within the subset of time regions comprising one or more instances of the CFRA resource, wherein the timing pattern for the CFRA resource is based at least in part on the subset of time regions.