Why do we have multiple Search Spaces in a single Coreset?

5G NR
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1

Hi Experts.

Why do we have multiple Search Spaces in a single Coreset?

Why can’t we define a single Search Space and let all UEs use the same Search Space?

2

Search space = area where UE blindly search it’s DCI.

Aggregation level, dci size, and location of DCI are not known to UE.

Bigger the area to search = more time UE will take to find its DCI.

So let’s have smaller search spaces, so let’s have categorized search spaces based on data type, so let’s help UE to save time and processing.

3

Thanks.

Does UE know which aggregation level to start with for blind decoding?

Does it start with the lowest AL a d moving on to higher AL?

Do we categorize ss based on 5qi/data type as well?

4

UE knows what all the aggregation levels are in the search space, and it also knows the number of candidates for each aggregation level.

UE can start with a lower aggregation level and move on to a higher one if it fails to decode DCIs.

Also, the allocation of DCI is not random it is based on a formula that is known to UE.

This also minimizes blind decoding.

5

Thanks!