1. WF on Bandwidth Part for DL common channel
3GPP TSG RAN WG1 Meeting RAN1 #90
Prague, Czech Republic 21st – 25th August 2017
Agenda item: R
WF on Bandwidth Part for DL common channel
LG Electronics, MediaTek, …

2. Background Agreement : (RAN1 NRAH#2)
At least one of configured DL BWPs includes one CORESET with common search space at least in primary component carrier
Agreement : (RAN1#89)
The maximum bandwidth for CORESET for RMSI scheduling and NR-PDSCH carrying RMSI should be equal to or smaller than a certain DL bandwidth of NR that all UE can support in each frequency range
Agreement : (RAN1#90)
For frequency location of CORESET for RMSI scheduling and NR-PDSCH for RMSI,
CORESET for RMSI scheduling and NR-PDSCH for RMSI does not have to be confined within the same BW of corresponding NR-PBCH
Bandwidth for CORESET and NR-PDSCH for RMSI is confined within the UE minimum bandwidth for the given frequency band
In configuration of a BWP, a UE is configured with BWP in terms of PRBs.
The offset between BWP and a reference point is implicitly or explicitly indicated to UE.

3. Motivation
NR system supports to operate within very wideband CC, but all of UE could not provide the capability for wideband operation. Hence, it is hard to operate initial access within system bandwidth.
Instead, NR can define BWP for initial access operation. Within the BWP, NR system can operate initial access procedure for SS/PBCH block transmission, system information delivery, paging and RACH procedure.
In RAN1 AH#2 meeting, it was agreed that at least one of configured DL BWPs includes one CORESET with common search space at least in primary component carrier.
So, it can be expected that at least RMSI, OSI, Paging, RACH msg.2/4 related downlink control information is transmitted at the CORESET for common search space, and associated downlink shared channel can be assigned within the DL BWP.
Also, it can be expected that SS/PBCH block is transmitted within the BWP.

4. Proposal
At least one of DL BWPs is used as BWP for downlink common channel (i.e. CORESET with common search space, and PDSCH for RMSI, OSI, Paging, RACH Msg.2/4).
CORESET with common search space, and PDSCH for RMSI, OSI, Paging, RACH msg.2/4 are confined within the BWP for DL common channel transmission.
Also, SS/PBCH block is confined within the BWP for DL common channel.
For the BWP for DL common channel, it is defined that the bandwidth of BWP is not narrower than the bandwidth of SS/PBCH block, and is equal to or smaller than UE minimum bandwidth for a given frequency range.
Following configurations of the BWP for DL common channel are provided by PBCH MIB.
The bandwidth of the BWP for DL common channel
The indication of relative frequency position between center of SS/PBCH block and center of bandwidth part for DL common channel

5. Appendix
Example of configuration for BWP for DL common channel