Search space overbooking and pruning
Methods, systems, and devices for wireless communication are described. In some cases, due to blind decoding and channel estimation (CE) limits, one or more user equipment (UE) specific search sets may be pruned for blind decoding and/or CE purposes. For instance, after hashing a set of common decoding candidates to control channel elements (CCEs) within the control region, the UE specific search sets may be pruned so as to conform to the blind decode limitation, since a common search space has already occupied a portion of the total blind decode limit. Following pruning, the UE may hash the sets of UE-specific decoding candidates associated with the one or more UE specific search sets to CCEs within the control region. The UE may further prune UE specific search sets, based on CE limits, while reusing CE for overlapping hashed locations.
1. A method for wireless communication at a user equipment (UE), comprising:
determining a number of available control channel elements (CCEs) of a control region for each of one or more search space sets based at least in part on a total number of available CCEs, the one or more search space sets associated with one or more sets of decoding candidates;
determining an applied one or more sets of decoding candidates comprising a first subset of the one or more sets of decoding candidates that have been hashed to a first subset of CCEs of the control region based at least in part on a number of available CCEs allocated for a first search space set of the one or more search space sets;
admitting, to the applied one or more sets of decoding candidates, a second subset of the one or more sets of decoding candidates having hashed locations overlapping with the first subset of CCEs;
determining that a number of CCEs corresponding to the applied one or more sets of decoding candidates is less than the total number of available CCEs;
admitting, to the applied one or more sets of decoding candidates and responsive to the determination that the number of CCEs is less than the total number of available CCEs, a third subset of the one or more sets of decoding candidates having hashed locations that are non-overlapping with the first subset of CCEs; and
monitoring the control region for the applied one or more sets of decoding candidates.
2. The method of claim 1 , further comprising:
determining a total number of available blind decodes for the one or more search space sets based at least in part on a blind decoding limitation of the UE;
determining a number of available blind decodes for each of the one or more search space sets based at least in part on the total number of available blind decodes; and
pruning the one or more sets of decoding candidates based at least in part on the number of available blind decodes for each of the one or more search space sets.
3. The method of claim 2 , wherein the one or more sets of decoding candidates comprise one or more sets of UE-specific decoding candidates of one or more UE-specific search space sets, the method further comprising:
identifying, for the control region, a set of common decoding candidates associated with a common search space set; and
determining that the set of common decoding candidates have been hashed to a second subset of CCEs of the control region, wherein the total number of available blind decodes is based at least in part on a number of decoding candidates of the set of common decoding candidates and the blind decoding limitation of the UE.
4. The method of claim 1 , wherein determining, for each of the one or more search space sets and for each aggregation level from a highest aggregation level to a lowest aggregation level of each of the one or more search space sets, the applied one or more sets of decoding candidates comprises:
identifying decoding candidates of each aggregation level spanning a set of CCEs less than or equal to a remaining number of the number of available CCEs;
determining that the identified decoding candidates have been hashed to the first subset of CCEs; and
including decoding candidates of a next aggregation level lower than a previous aggregation level that have been hashed to the first subset of CCEs.
5. The method of claim 1 , wherein the one or more sets of decoding candidates comprise one or more sets of UE-specific decoding candidates of one or more UE-specific search space sets, the method further comprising:
identifying, for the control region, a set of common decoding candidates associated with a common search space set; and
determining that the set of common decoding candidates have been hashed to a second subset of CCEs of the control region, wherein the total number of available CCEs is based at least in part on a CCE channel estimation limitation and the second subset of CCEs.
6. An apparatus for wireless communication 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:
determine a number of available control channel elements (CCEs) of a control region for each of one or more search space sets based at least in part on a total number of available CCEs, the one or more search space sets associated with one or more sets of decoding candidates;
determine an applied one or more sets of decoding candidates comprising a first subset of the one or more sets of decoding candidates that have been hashed to a first subset of CCEs of the control region based at least in part on a number of available CCEs allocated for a first search space set of the one or more search space sets;
admit, to the applied one or more sets of decoding candidates, a second subset of the one or more sets of decoding candidates having hashed locations overlapping with the first subset of CCEs;
determine that a number of CCEs corresponding to the applied one or more sets of decoding candidates is less than the total number of available CCEs;
admit, to the applied one or more sets of decoding candidates and responsive to the determination that the number of CCEs is less than the total number of available CCEs, a third subset of the one or more sets of decoding candidates having hashed locations that are non-overlapping with the first subset of CCEs; and
monitor the control region for the applied one or more sets of decoding candidates.
7. The apparatus of claim 6 , wherein the instructions are further executable by the processor to cause the apparatus to:
determine a total number of available blind decodes for the one or more search space sets based at least in part on a blind decoding limitation of the UE;
determine a number of available blind decodes for each of the one or more search space sets based at least in part on the total number of available blind decodes; and
prune the one or more sets of decoding candidates based at least in part on the number of available blind decodes for each of the one or more search space sets.
8. The apparatus of claim 7 , wherein the one or more sets of decoding candidates comprise one or more sets of UE-specific decoding candidates of one or more UE-specific search space sets, and the instructions are further executable by the processor to cause the apparatus to:
identify, for the control region, a set of common decoding candidates associated with a common search space set; and
determine that the set of common decoding candidates have been hashed to a second subset of CCEs of the control region, wherein the total number of available blind decodes is based at least in part on a number of decoding candidates of the set of common decoding candidates and the blind decoding limitation of the UE.
9. The apparatus of claim 6 , wherein the instructions to determining, for each of the one or more search space sets and for each aggregation level from a highest aggregation level to a lowest aggregation level of each of the one or more search space sets, the applied one or more sets of decoding candidates are executable by the processor to cause the apparatus to:
identify decoding candidates of each aggregation level spanning a set of CCEs less than or equal to a remaining number of the number of available CCEs;
determine that the identified decoding candidates have been hashed to the first subset of CCEs; and
include decoding candidates of a next aggregation level lower than a previous aggregation level that have been hashed to the first subset of CCEs.
10. The apparatus of claim 6 , wherein the one or more sets of decoding candidates comprise one or more sets of UE-specific decoding candidates of one or more UE-specific search space sets, and the instructions are further executable by the processor to cause the apparatus to:
identify, for the control region, a set of common decoding candidates associated with a common search space set; and
determine that the set of common decoding candidates have been hashed to a second subset of CCEs of the control region, wherein the total number of available CCEs is based at least in part on a CCE channel estimation limitation and the second subset of CCEs.
11. An apparatus for wireless communication at a user equipment (UE), comprising:
means for determining a number of available control channel elements (CCEs) of a control region for each of one or more search space sets based at least in part on a total number of available CCEs, the one or more search space sets associated with one or more sets of decoding candidates;
means for determining an applied one or more sets of decoding candidates comprising a first subset of the one or more sets of decoding candidates that have been hashed to a first subset of CCEs of the control region based at least in part on a number of available CCEs allocated for a first search space set of the one or more search space sets;
means for admitting, to the applied one or more sets of decoding candidates, a second subset of the one or more sets of decoding candidates having hashed locations overlapping with the first subset of CCEs;
means for determining that a number of CCEs corresponding to the applied one or more sets of decoding candidates is less than the total number of available CCEs;
means for admitting, to the applied one or more sets of decoding candidates and responsive to the determination that the number of CCEs is less than the total number of available CCEs, a third subset of the one or more sets of decoding candidates having hashed locations that are non-overlapping with the first subset of CCEs; and
means for monitoring the control region for the applied one or more sets of decoding candidates.
12. The apparatus of claim 11 , further comprising:
means for determining a total number of available blind decodes for the one or more search space sets based at least in part on a blind decoding limitation of the UE;
means for determining a number of available blind decodes for each of the one or more search space sets based at least in part on the total number of available blind decodes; and
means for pruning the one or more sets of decoding candidates based at least in part on the number of available blind decodes for each of the one or more search space sets.
13. The apparatus of claim 12 , wherein the one or more sets of decoding candidates comprise one or more sets of UE-specific decoding candidates of one or more UE-specific search space sets, the apparatus further comprising:
means for identifying, for the control region, a set of common decoding candidates associated with a common search space set; and
means for determining that the set of common decoding candidates have been hashed to a second subset of CCEs of the control region, wherein the total number of available blind decodes is based at least in part on a number of decoding candidates of the set of common decoding candidates and the blind decoding limitation of the UE.
14. The apparatus of claim 11 , wherein the means for determining, for each of the one or more search space sets and for each aggregation level from a highest aggregation level to a lowest aggregation level of each of the one or more search space sets, the applied one or more sets of decoding candidates comprises:
means for identifying decoding candidates of each aggregation level spanning a set of CCEs less than or equal to a remaining number of the number of available CCEs;
means for determining that the identified decoding candidates have been hashed to the first subset of CCEs; and
means for including decoding candidates of a next aggregation level lower than a previous aggregation level that have been hashed to the first subset of CCEs.
15. The apparatus of claim 11 , wherein the one or more sets of decoding candidates comprise one or more sets of UE-specific decoding candidates of one or more UE-specific search space sets, the apparatus further comprising:
means for identifying, for the control region, a set of common decoding candidates associated with a common search space set; and
means for determining that the set of common decoding candidates have been hashed to a second subset of CCEs of the control region, wherein the total number of available CCEs is based at least in part on a CCE channel estimation limitation and the second subset of CCEs.
16. A non-transitory computer-readable medium storing code for wireless communication at a user equipment (UE), the code comprising instructions executable by a processor to:
determine a number of available control channel elements (CCEs) of a control region for each of one or more search space sets based at least in part on a total number of available CCEs, the one or more search space sets associated with one or more sets of decoding candidates;
determine an applied one or more sets of decoding candidates comprising a first subset of the one or more sets of decoding candidates that have been hashed to a first subset of CCEs of the control region based at least in part on a number of available CCEs allocated for a first search space set of the one or more search space sets;
admit, to the applied one or more sets of decoding candidates, a second subset of the one or more sets of decoding candidates having hashed locations overlapping with the first subset of CCEs;
determine that a number of CCEs corresponding to the applied one or more sets of decoding candidates is less than the total number of available CCEs;
admit, to the applied one or more sets of decoding candidates and responsive to the determination that the number of CCEs is less than the total number of available CCEs, a third subset of the one or more sets of decoding candidates having hashed locations that are non-overlapping with the first subset of CCEs; and
monitor the control region for the applied one or more sets of decoding candidates.
17. The non-transitory computer-readable medium of claim 16 , wherein the instructions are further executable to:
determine a total number of available blind decodes for the one or more search space sets based at least in part on a blind decoding limitation of the UE;
determine a number of available blind decodes for each of the one or more search space sets based at least in part on the total number of available blind decodes; and
prune the one or more sets of decoding candidates based at least in part on the number of available blind decodes for each of the one or more search space sets.
18. The non-transitory computer-readable medium of claim 17 , wherein the one or more sets of decoding candidates comprise one or more sets of UE-specific decoding candidates of one or more UE-specific search space sets, and the instructions are executable to:
identify, for the control region, a set of common decoding candidates associated with a common search space set; and
determine that the set of common decoding candidates have been hashed to a second subset of CCEs of the control region, wherein the total number of available blind decodes is based at least in part on a number of decoding candidates of the set of common decoding candidates and the blind decoding limitation of the UE.
19. The non-transitory computer-readable medium of claim 16 , wherein the instructions to determining, for each of the one or more search space sets and for each aggregation level from a highest aggregation level to a lowest aggregation level of each of the one or more search space sets, the applied one or more sets of decoding candidates are executable to:
identify decoding candidates of each aggregation level spanning a set of CCEs less than or equal to a remaining number of the number of available CCEs;
determine that the identified decoding candidates have been hashed to the first subset of CCEs; and
include decoding candidates of a next aggregation level lower than a previous aggregation level that have been hashed to the first subset of CCEs.
20. The non-transitory computer-readable medium of claim 16 , wherein the one or more sets of decoding candidates comprise one or more sets of UE-specific decoding candidates of one or more UE-specific search space sets, and the instructions are executable to:
identify, for the control region, a set of common decoding candidates associated with a common search space set; and
determine that the set of common decoding candidates have been hashed to a second subset of CCEs of the control region, wherein the total number of available CCEs is based at least in part on a CCE channel estimation limitation and the second subset of CCEs.