Can we have multiple UEs on same search space of the coreset?

5G NR
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1

Hi Experts.
Can we have multiple UEs on same search space of the coreset?

2

I would say yes.

3

So the DCI info is organized by REs index?

4

It’s not?
Because coreset has 12 search space at max so each search space is specific for UE.
Means if I have 12 UEs in that coreset so each UE will have his own searchspace in that coreset, no?

5

But isn’t search space also for common?
Which would mean more than one UE can use it.

I am still not sure on how DCI are mapped.

6

Searchspace is specific for UE.
Coreset is common Yes.

7

But search space can be part of SIB1, which would be read and used by all UEs.

8

Let’s assume that’s what happens then we will have opportunity collisions means dci info for UE1 will be reqd by uE2 but uE2 can’t succeed to decode so opportunity collisions.

And size of each searchspace is equal to size of coreset so assume one UE needs more cces in specific searchspace. Can’t be scheduled.

But I’m confused. :frowning:

9

I would think collision would happen, but that it also expected because no dedicated signalling is happening at that time.

10

We can reduce that collisions by grouping RANTIs?
Means like all RNTIs in the same coreset that all have same index of search space for DCI searching to allocate for each one of them another search space?
Because each coreset has max 12 search spaces.

So by this we can have max 12 UE per coreset (each searchspace has its own UE).

11

Assume coreset frequency allocation = 120 RBs and 1 OFDM symbol then there are 20 CCEs which can accomodate up to 20 different DCIs assuming AL1 for all DCIs
Search space is a receiving concept which help reduces the time each UE finds its own DCI

For SIBs, paging and RAR,one DCI can be successfully decoded by multiple UEs

1 Like
12

Any idea how do we design the places of the search spaces for different aggregation levels in order to decrease the UEs opportunities collision between eachother once reading dcis (they do blind decode)?

13

Different searches can overlap each other and can calculate the occurrence of each search space by monitoring slot and duration.
How to ensure the collision?

14

Can one ue uses two coreset through one search space id?
In congested case.
Can multiple UEs of different aggregation level within searchplace overlap between each other?
It is based on nrb coreset but any limit on that.

15

No.
Each search space is associated with a specific coreset.

16

How many frequency possible in one coreset? 6 only max?
As it can have 10 search space, so it should have more in freq position?

17

But can the same searchspace belong to different coresets (different coresets ids)?

18

Nope. Coreset to searchspace has 1 to.many mapping. Not the other way around.

19

But a coreset has max 10 search space.
And in active BWP we can have 40 search space.
So it means they are different.
Through parameter search space id.
So a active BWP can have 40 search space with diff agg level so if configuration are proper can it support 40 UE at a time for scheduling there should be some for PDCCH DMRS so assume atlest 30 UEe can be supported through UE common coreset as common coreset is for paging SIB info.

20

So you mean each coreset has its unique searchspaces not related to other searchspaces of other coresets, right?