1. Overview of open issues in 6.3.1.3
3GPP TSG RAN WG1 Meeting NR# R1-171xxxx
Nagoya, Japan, 18th – 21st, September 2017
Agenda Item:
Overview of open issues in
Nokia, NSB

2. RAN1#90 agreements Agreements:
A UE can be configured by RRC signaling with one or more resource set(s)
The UE shall assume that the scheduled PDSCH is rate-matched around the resource set(s) when the scheduled PDSCH overlaps
FFS: exact configuration of a resource set including granularity.
A UE can be configured by UE-specific RRC signaling to identify resource set(s) for which the PDSCH may or may not be mapped based on the L1 signaling.
For a scheduled PDSCH overlapping with given resource set(s), L1 signalling indicates whether the scheduled PDSCH is rate-matched around the resource set(s) or is mapped to the resources in the resource set(s).
FFS: details of the L1 signaling
FFS: exact configuration of a resource set including granularity
At least the following is supported
When the scheduled PDSCH overlaps with the PDCCH scheduling the PDSCH, the UE shall assume that the scheduled PDSCH is rate-matched around the PDCCH scheduling the PDSCH
Other forms of resource sharing between PDCCH and PDSCH are not precluded

3. Open issues Means of L1 signaling RRC configuration
User-specific (majority prefers this option )
Group-common (one company )
Group-common and User-specific (one company)
Connection to SFI GC (one company)
RRC configuration
RE level (two companies would like to support also RE level)
PRB level x OFDM symbol level (majority)
Granularity of resource reuse
CORESET/RESET level: (majority)
Smaller than CORESET/RESET: Search-space, PDCCH Candidate, CCE, RB-symbol, etc (two companies)
L1 signaling details
Once above three points are resolved, we can start discussing details
Note: RESET denotes the resource set (see slide 2) and can be at least CORESET of other UE

4. L1 signaling means - Arguments to support L1 user-specific signaling
Better reliability: the reception of PDSCH does not depend on GC-PDCCH decoding. Failing to decode GC-PDCCH results in failure of PDSCH decoding, because of rate- matching assumption is wrong.
Latency and power consumption: no need to monitor GC-PDCCH.
Efficiency of resource reuse (example on right): In case of group-common, UE1 cannot reuse resources colliding with yellow CORESET/RESET. Contrary, with UE specific signaling UE1 can reuse.
Lower signaling overhead: no need for transmitting GC CRC (21bits)
Example: One CORESET schedules 3 PDSCH

5. L1 signaling means - Arguments to support L1 GC signaling
Less overhead
Similarity/commonality to preemption/SFI GC-PDCCH
gNB implementation issue

6. RRC configuration for RESET
Alt1: Set of RE elements (two companies)
Use-case: NR CSI-RS, Future compatibility resource, …
Alt2: Non-continuous RBs and continuous OFDM symbols (majority of companies)
Use-case: CORESETs of other UEs, Future compatibility resource, …
Alt3: Non-continuous RBs and bitmap of OFDM symbols (two companies)
Use-case: To enable merging of multiple slot-based/non-slot-based CORESETs into one RESET, Future compatibility resource …
Note: at least 2 companies express concern with linking L1-based control resource reuse framework with future compatible resource.
Note: one company, the NR reserved resource cannot be configured as RESET for L1-based control resource reuse.

7. RRC configuration for RESET being part or not-part of L1 signalling
Illustration of combining CORESETs to RESETs

8. Granularity of L1 indication
CORESET/RESET level (majority prefers this option)
Advantages: Simple L1 signalling design, …
Disadvantages: Lower efficiency, …
Smaller than CORESET/RESET (e.g. subset of PRBs, search-space, candidate ) ( three companies proposed this option)
Advantages: Better efficiency, …
Disadvantages: More complicated L1 design, …
one company mentioned default rate-matching around GC-PDCCH search-space if part of CORESET configured for L1 reuse.
one company proposed to split RESET into parts, if other RESET is fully outside of PDSCH

9. Proposed options for L1 signalling on RESET/CORESET level
Option 1: 1 bit per CORESET/RESET configured for L1 reuse (Samsung)
Option 2: 1 bit for all CORESETs/RESETs configured for L1 reuse
Option 3: 1 bit per each configured group of CORESETs/RESETs configured for L1 reuse
Note: One RESET can be only in one group
Option 4: 1 table-entry per combination of CORESETs/RESETs configured for L1 reuse
Note: One RESET can be in multiple groups
Option 5: preconfigure X RESETs/CORESET and indicated the one PDSCH is rate-matched around
One company would like to limit overhead to max 2bits.
One company considers joint coding of L1 control reuse with PDSCH start-end
Several companies mention that overhead in scheduling DCI should be limited.