CORESET, Search Space and BWP

CORESET: Control Resource Set, This is basically the PDCCH decode region.

In LTE system, PDCCH is span across the complete system bandwidth in frequency domain and in time domain PCFICH tells about the number of OFDM sysmbol. Control region is always at the starting of subframe.


But in NR, there are lot flexibility for PDCCH control region also and it is not necessary to span across the complete system bandwidth as like LTE.

N/w can define common control region and UE specific control region.

CORESET and search space both are closely associated with each other.

Below are the few numbers about CORESET, BWP & Search space
1. Number of CORESET  is limited to 3 per BWP including both common and UE specific.
2. Number of BWP per serving cell is - 4
3. So Max number of CORESET per serving cell is - 12 ( controlResourceSetId, range is 0 -11)
4. Max number of search space per BWP is - 10.
5. Max search space per serving cell is -  number of BWP per serving cell (4 )* search space per BWP (10)  = 40    // so searchspaceID range is 0 - 39
6. CORESET ID (controlResourceSetId) is unique among the BWPs of a ServingCell.
7. Each search space is associated with some CORESET.