Relaxed control channel element and blind decoding overbooking and dropping for new radio ultra-reliable low-latency communications
Methods, systems, and devices for wireless communication are described. Generally, the described techniques provide for efficiently limiting a number of blind decoding attempts or control channel elements (CCEs) that a user equipment (UE) is configured to monitor to limit complexity at the UE. When a UE is configured to use blind decoding for monitoring CCEs in multiple spans in a slot for control information from a base station, the UE may be configured to perform dropping of blind decoding candidates or CCEs in a first temporal span in the slot. In other words, the UE may identify a dropping rule to drop CCE monitoring occasions or blind decoding attempts in excess of a maximum number of non-overlapping CCEs per span or a maximum number of blind decoding attempts per span, respectively, and the UE may apply the dropping rule to the first temporal span within the slot.
1. A method for wireless communications at a user equipment (UE), comprising:
monitoring control channel elements in a control resource set in accordance with at least one of a maximum number of downlink control channel candidates per span within a slot or a maximum number of non-overlapping control channel elements per span within the slot;
identifying a dropping rule for the UE to drop control channel element monitoring occasions or downlink control channel candidates in excess of the maximum number of non-overlapping control channel elements per span or the maximum number of downlink control channel candidates per span, respectively; and
applying the dropping rule to a fixed span within the slot.
2. The method of claim 1 , further comprising:
determining the fixed span within the slot in which the UE is to apply the dropping rule, wherein applying the dropping rule to the fixed span within the slot comprises:
dropping one or more control channel element monitoring occasions or one or more downlink control channel candidates for the fixed span.
3. The method of claim 2 , wherein the fixed span includes a first temporal span within the slot.
4. The method of claim 2 , wherein the fixed span includes a span in which a common search space is present.
5. The method of claim 1 , further comprising:
determining a maximum number of spans in which the UE is to apply the dropping rule, wherein applying the dropping rule to the fixed span within the slot is based at least in part on the maximum number of spans determined by the UE.
6. The method of claim 5 , wherein the maximum number of spans is common for different span timing and length configurations for the UE.
7. The method of claim 5 , wherein the maximum number of spans is based at least in part on a UE capability, the method further comprising:
transmitting the UE capability to a network device; and
identifying that a number of spans that include a common search space within the slot is in accordance with the UE capability.
8. The method of claim 5 , wherein the maximum number of spans is different for different span timing and length configurations for the UE.
9. The method of claim 5 , wherein determining the maximum number of spans comprises:
determining the maximum number of spans in which the UE is able to apply the dropping rule based at least in part on a physical downlink shared channel (PDSCH) or physical uplink shared channel (PUSCH) minimum processing time capability of a cell with which the UE communicates over the slot.
10. The method of claim 1 , wherein applying the dropping rule to the fixed span within the slot comprises:
dropping one or more control channel element monitoring occasions or one or more downlink control channel candidates for only a number of spans in which a common search space is present.
11. The method of claim 1 , wherein applying the dropping rule to the fixed span within the slot comprises:
dropping one or more control channel element monitoring occasions or one or more downlink control channel candidates for a number of spans in which a common search space is present and when the slot is for communications with either a primary cell or a primary-secondary cell.
12. The method of claim 1 , wherein applying the dropping rule to the fixed span within the slot comprises:
refraining from applying the dropping rule in a number of spans that do not include a common search space.
13. The method of claim 1 , wherein applying the dropping rule to the fixed span within the slot comprises:
refraining from applying the dropping rule to any span within the slot based on the slot not including a common search space.
14. A method for wireless communications at a network device, comprising:
identifying a fixed span within a slot in which a user equipment (UE) is to apply a dropping rule, wherein the dropping rule indicates that the UE is to drop control channel element monitoring occasions or downlink control channel candidates in accordance with the dropping rule;
configuring one or more common search spaces within spans of the slot for communication with the UE such that at least the fixed span within the slot includes a common search space; and
indicating, to the UE, a common search space configuration in accordance with the configuring.
15. The method of claim 14 , wherein the fixed span is a first temporal span within the slot.
16. The method of claim 14 , wherein the common search space is an only common search space configured within the spans of the slot for communication with the UE.
17. A method for wireless communications at a network device, comprising:
identifying a maximum number of spans per slot in which a user equipment (UE) is to apply a dropping rule, wherein the dropping rule indicates that the UE is to drop control channel element monitoring occasions or downlink control channel candidates in accordance with the dropping rule;
configuring one or more common search spaces within spans of a slot for communication with the UE such that a number of spans within the slot that include a common search space is less than or equal to the maximum number of spans per slot; and
indicating, to the UE, a common search space configuration in accordance with the configuring.
18. The method of claim 17 , wherein the maximum number of spans per slot is common for different span timing and length configurations for the UE.
19. The method of claim 17 , wherein the maximum number of spans per slot is different for different span timing and length configurations for the UE.
20. The method of claim 17 , wherein the maximum number of spans is based at least in part on a physical downlink shared channel (PDSCH) or physical uplink shared channel (PUSCH) minimum processing time capability of a cell associated with the network device and with which the UE communicates over the slot.
21. An apparatus for wireless communications at a user equipment (UE), comprising:
a processor,
memory coupled with the processor; and
instructions stored in the memory and executable by the processor to cause the apparatus to:
monitor control channel elements in a control resource set in accordance with at least one of a maximum number of downlink control channel candidates per span within a slot or a maximum number of non-overlapping control channel elements per span within the slot;
identify a dropping rule for the UE to drop control channel element monitoring occasions or downlink control channel candidates in excess of the maximum number of non-overlapping control channel elements per span or the maximum number of downlink control channel candidates per span, respectively; and
apply the dropping rule to a fixed span within the slot.
22. The apparatus of claim 21 , wherein the instructions are further executable by the processor to cause the apparatus to:
determine the fixed span within the slot in which the UE is to apply the dropping rule, wherein the instructions to apply the dropping rule to the fixed span within the slot are executable by the processor to cause the apparatus to:
drop one or more control channel element monitoring occasions or one or more downlink control channel candidates for the fixed span.
23. The apparatus of claim 22 , wherein the fixed span includes a first temporal span within the slot.
24. The apparatus of claim 22 , wherein the fixed span includes a span in which a common search space is present.
25. The apparatus of claim 21 , wherein the instructions are further executable by the processor to cause the apparatus to:
determine a maximum number of spans in which the UE is to apply the dropping rule, wherein applying the dropping rule to the fixed span within the slot is based at least in part on the maximum number of spans.
26. The apparatus of claim 25 , wherein the maximum number of spans is common for different span timing and length configurations for the UE.
27. The apparatus of claim 25 , wherein the maximum number of spans is based at least in part on a UE capability, and wherein the instructions are further executable by the processor to cause the apparatus to:
transmit the UE capability to a network device; and
identify that a number of spans that include a common search space within the slot is in accordance with the UE capability.
28. The apparatus of claim 25 , wherein the maximum number of spans is different for different span timing and length configurations for the UE.
29. The apparatus of claim 25 , wherein the instructions to determine the maximum number of spans are executable by the processor to cause the apparatus to:
determine the maximum number of spans in which the UE is able to apply the dropping rule based at least in part on a physical downlink shared channel (PDSCH) or physical uplink shared channel (PUSCH) minimum processing time capability of a cell with which the UE communicates over the slot.
30. The apparatus of claim 21 , wherein the instructions to apply the dropping rule to the fixed span within the slot are executable by the processor to cause the apparatus to:
drop one or more control channel element monitoring occasions or one or more downlink control channel candidates for only a number of spans in which a common search space is present.
31. The apparatus of claim 21 , wherein the instructions to apply the dropping rule to the fixed span within the slot are executable by the processor to cause the apparatus to:
drop one or more control channel element monitoring occasions or one or more downlink control channel candidates for a number of spans in which a common search space is present and when the slot is for communications with either a primary cell or a primary-secondary cell.
32. The apparatus of claim 21 , wherein the instructions to apply the dropping rule to the fixed span within the slot are executable by the processor to cause the apparatus to:
refrain from applying the dropping rule in a number of spans that do not include a common search space.
33. The apparatus of claim 21 , wherein the instructions to apply the dropping rule to the fixed span within the slot are executable by the processor to cause the apparatus to:
refrain from applying the dropping rule to any span within the slot based on the slot not including a common search space.
34. An apparatus for wireless communications at a network device, comprising:
a processor,
memory coupled with the processor; and
instructions stored in the memory and executable by the processor to cause the apparatus to:
identify a fixed span within a slot in which a user equipment (UE) is to apply a dropping rule, wherein the dropping rule indicates that the UE is to drop control channel element monitoring occasions or downlink control channel candidates in accordance with the dropping rule;
configure one or more common search spaces within spans of the slot for communication with the UE such that at least the fixed span within the slot includes a common search space; and
indicate, to the UE, a common search space configuration in accordance with the configuring.
35. The apparatus of claim 34 , wherein the fixed span is a first temporal span within the slot.
36. The apparatus of claim 34 , wherein the common search space is an only common search space configured within the spans of the slot for communication with the UE.
37. An apparatus for wireless communications at a network device, comprising:
a processor,
memory coupled with the processor; and
instructions stored in the memory and executable by the processor to cause the apparatus to:
identify a maximum number of spans per slot in which a user equipment (UE) is to apply a dropping rule, wherein the dropping rule indicates that the UE is to drop control channel element monitoring occasions or downlink control channel candidates in accordance with the dropping rule;
configure one or more common search spaces within spans of a slot for communication with the UE such that a number of spans within the slot that include a common search space is less than or equal to the maximum number of spans per slot; and
indicate, to the UE, a common search space configuration in accordance with the configuring.
38. The apparatus of claim 37 , wherein the maximum number of spans is common for different span timing and length configurations for the UE.
39. The apparatus of claim 37 , wherein the maximum number of spans is different for different span timing and length configurations for the UE.
40. The apparatus of claim 37 , wherein the maximum number of spans is based at least in part on a physical downlink shared channel (PDSCH) or physical uplink shared channel (PUSCH) minimum processing time capability of a cell associated with the network device and with which the UE communicates over the slot.
41. An apparatus for wireless communications at a user equipment (UE), comprising:
means for monitoring control channel elements in a control resource set in accordance with at least one of a maximum number of downlink control channel candidates per span within a slot or a maximum number of non-overlapping control channel elements per span within the slot;
means for identifying a dropping rule for the UE to drop control channel element monitoring occasions or downlink control channel candidates in excess of the maximum number of non-overlapping control channel elements per span or the maximum number of downlink control channel candidates per span, respectively; and
means for applying the dropping rule to a fixed span within the slot.
42. An apparatus for wireless communications at a network device, comprising:
means for identifying a fixed span within a slot in which a user equipment (UE) is to apply a dropping rule, wherein the dropping rule indicates that the UE is to drop control channel element monitoring occasions or downlink control channel candidates in accordance with the dropping rule;
means for configuring one or more common search spaces within spans of the slot for communication with the UE such that at least the fixed span within the slot includes a common search space; and
means for indicating, to the UE, a common search space configuration in accordance with the configuring.
43. An apparatus for wireless communications at a network device, comprising:
means for identifying a maximum number of spans per slot in which a user equipment (UE) is to apply a dropping rule, wherein the dropping rule indicates that the UE is to drop control channel element monitoring occasions or downlink control channel candidates in accordance with the dropping rule;
means for configuring one or more common search spaces within spans of a slot for communication with the UE such that a number of spans within the slot that include a common search space is less than or equal to the maximum number of spans per slot; and
means for indicating, to the UE, a common search space configuration in accordance with the configuring.
44. A non-transitory computer-readable medium storing code for wireless communications at a user equipment (UE), the code comprising instructions executable by a processor to:
monitor control channel elements in a control resource set in accordance with at least one of a maximum number of downlink control channel candidates per span within a slot or a maximum number of non-overlapping control channel elements per span within the slot;
identify a dropping rule for the UE to drop control channel element monitoring occasions or downlink control channel candidates in excess of the maximum number of non-overlapping control channel elements per span or the maximum number of downlink control channel candidates per span, respectively; and
apply the dropping rule to a fixed span within the slot.
45. A non-transitory computer-readable medium storing code for wireless communications at a network device, the code comprising instructions executable by a processor to:
identify a fixed span within a slot in which a user equipment (UE) is to apply a dropping rule, wherein the dropping rule indicates that the UE is to drop control channel element monitoring occasions or downlink control channel candidates in accordance with the dropping rule;
configure one or more common search spaces within spans of the slot for communication with the UE such that at least the fixed span within the slot includes a common search space; and
indicate, to the UE, a common search space configuration in accordance with the configuring.
46. A non-transitory computer-readable medium storing code for wireless communications at a network device, the code comprising instructions executable by a processor to:
identify a maximum number of spans per slot in which a user equipment (UE) is to apply a dropping rule, wherein the dropping rule indicates that the UE is to drop control channel element monitoring occasions or downlink control channel candidates in accordance with the dropping rule;
configure one or more common search spaces within spans of a slot for communication with the UE such that a number of spans within the slot that include a common search space is less than or equal to the maximum number of spans per slot; and
indicate, to the UE, a common search space configuration in accordance with the configuring.