PDCCH-ConfigCommon is used mainly to configure various common search space. (Refer to this page if you want to know of the details of various search space).

PDCCH-ConfigCommon ::=                  SEQUENCE {
    controlResourceSetZero                ControlResourceSetZero OPTIONAL, 
    commonControlResourceSet              ControlResourceSet OPTIONAL, -- Need R
    searchSpaceZero                       SearchSpaceZero OPTIONAL, -- Cond InitialBWP-Only
    commonSearchSpaceList                 SEQUENCE (SIZE(1..4)) OF SearchSpace OPTIONAL, 
    searchSpaceSIB1                       SearchSpaceId OPTIONAL, -- Need S
    searchSpaceOtherSystemInformation     SearchSpaceId OPTIONAL, -- Need S
    pagingSearchSpace                     SearchSpaceId OPTIONAL, -- Need S
    ra-SearchSpace                        SearchSpaceId
    ...

}
ControlResourceSetZero ::= INTEGER (0..15)
                

controlResourceSetZero : Parameters of the common CORESET#0. The values are interpreted like the corresponding bits in MIB pdcch-ConfigSIB1. Even though this field is only configured in the initial BWP (BWP#0) controlResourceSetZero can be used in search spaces configured in other DL BWP(s) than the initial DL BWP

commonControlResourceSet : An additional common control resource set which may be configured and used for RAR/paging/system information. If the network configures this field, it uses a ControlResourceSetId other than 0 for this ControlResourceSet.

searchSpaceZero : Parameters of the common SearchSpace#0. The values are interpreted like the corresponding bits in MIB pdcch-ConfigSIB1. Even though this field is only configured in the initial BWP (BWP#0) searchSpaceZero can be used in search spaces configured in other DL BWP(s) than the initial DL BWP

commonSearchSpaceList : A list of additional common search spaces. If the network configures this field, it uses the SearchSpaceIds other than 0.

searchSpaceSIB1 : ID of the search space for SIB1 message. If the field is absent, the UE does not receive SIB1 in this BWP.

searchSpaceOtherSystemInformation : ID of the Search space for other system information, i.e., SIB2 and beyond. Corresponds to L1 parameter 'osi-SearchSpace'. If the field is absent, the UE does not receive other system information in this BWP.

pagingSearchSpace : ID of the Search space for paging. Corresponds to L1 parameter 'paging-SearchSpace'. If the field is absent, the UE does not receive paging in this BWP

ra-SearchSpace : ID of the Search space for random access procedure. Corresponds to L1 parameter 'ra-SearchSpace'. If the field is absent, the UE does not receive RAR in this BWP. This field is mandatory present in the DL BWP(s)

Reference

[1] Type0-PDCCH common search space