1. Samsung, KT Corp., NTT DOCOMO, Verizon, [ZTE], [CATT], [Intel]
3GPP TSG RAN WG1 Meeting #88
Athens, Greece, 13th - 17th Feb 2017
Agenda item R
WF on beam indication
Samsung, KT Corp., NTT DOCOMO, Verizon, [ZTE], [CATT], [Intel]

2. Background RAN1#86 Agreements:
Beam management = a set of L1/L2 procedures to acquire and maintain a set of TRP(s) and/or UE beams that can be used for DL and UL transmission/reception, which include at least following aspects:
Beam determination= for TRP(s) or UE to select of its own Tx/Rx beam(s).
Beam measurement = for TRP(s) or UE to measure characteristics of received beamformed signals
Beam reporting = for UE to report information of beamformed signal(s) based on beam measurement
Beam sweeping = operation of covering a spatial area, with beams transmitted and/or received during a time interval in a predetermined way.

3. Background RAN1 NR ad hoc Agreements:
For reception of DL control channel, support indication of spatial QCL assumption between an DL RS antenna port(s), and DL RS antenna port(s) for demodulation of DL control channel
FFS: signaling method
Note: Indication may not be needed for some cases:
For reception of DL data channel, support indication of spatial QCL assumption between DL RS antenna port(s) and DMRS antenna port(s) of DL data channel
FFS: which DL RS(s) to use for this purpose
Different set of DMRS antenna port(s) for the DL data channel can be indicated as QCL with different set of RS antenna port(s)
Option 1: Information indicating the RS antenna port(s) is indicated via DCI
FFS: whether the information indicating the RS antenna port(s) will be assumed only for the scheduled “PDSCH” or until the next indication
Option 2: Information indicating the RS antenna port(s) is indicated via MAC-CE, and will be assumed until the next indication
Option 3: Information indicating the RS antenna port(s) is indicated via a combination of MAC CE and DCI
At least one option is supported
FFS: whether to support either or both options
FFS: whether the information indicating the RS antenna port(s) for DMRS ports for DL control channel also applies to DMRS ports for DL data channel

4. Motivation
MAC CE signalling can provide good reliable and reasonable latency and is suitable for beam indication for UE-specific PDCCH
Note: Beam management for common PDCCH should not involving signalling
The beam indication for PDSCH beam management needs to be dynamic in order to support transmission schemes, such as the dynamic TRP selection

5. Proposal 1
NR beam management should include the aspect of beam indication. The beam indication is defined as:
Beam indication= for NW to inform UE of the Tx beam(s) related information.

6. Proposal 2
Beam indication based on DCI signalling (DL grant) is supported for unicast PDSCH reception
The information indicating the RS antenna port(s) which is QCL-ed with DMRS antenna port(s) is assumed only for the scheduled PDSCH
The information indicates the RS antenna port(s) which is QCL-ed with DMRS antenna port(s) from set of RS antenna port(s)
FFS the indication is assumed only for the scheduled PDSCH or until next indication
When the above information is included, FFS if there should be a scheduling offset
FFS: How the set of RS antenna port(s) which is QCL-ed with DM-RS antenna port(s) is configured, e.g. RRC, or RRC+MAC CE
FFS: Beam indication for receiving fall back unicast PDSCH
FFS: Beam indication for receiving (UE-group) common PDSCH for RRC connected UE
Candidate signalling methods for beam indication for a NR-PDCCH (i.e. configuration method to monitor NR-PDCCH)
MAC CE signalling
RRC signalling