Chih-Hsuan Chen CHTTL 2017/05/05

Transcription

1 Chih-Hsuan Chen CHTTL 2017/05/05 1/26

2 3GPP NR timeline NR overview NR MIMO 2/26

3 In March, NR phase-1 WI is approved: NSA to be completed by Dec., 2017 SA to be completed by June, 2018 All L1 and L2 to user plane to be completed by Dec., 2017 NSA: Non Standalone SA: Standalone NSA Option 3: EPC core and LTE anchor Source: RP /26

4 NR 4/26 Ref: TR , Picture source: Qualcomm

5 Duplexing: support TDD and FDD Channel coding for embb: Data channel: LDPC code Control channel: Polar code Waveform for up to 40GHz CP-OFDM based for DL and UL For embb and URLLC DFT-s-OFDM based for UL only For embb and single stream Modulation DL/UL supports: QPSK, 16QAM, 64QAM, 256QAM 0.5 pi-bpsk for DFT-s-OFDM Ref: TR /26

6 Flexible numerologies SCS=15*2 n khz (at least 15~480kHz) Frame structure Frame length=10ms, subframe length=1ms Number of subcarrier per PRB=12 Slot : For SCS <= 60kHz, 7 or 14 OFDM symbols For SCS > 60kHz, 14 OFDM symbols Mini-slot: For >6GHz, length=1 symbol is supported For URLLC, at least length=2 symbols is supported Multi-beam based operation for mmwave system Initial access and mobility, MIMO, etc 6/26

7 Design concept of NR MIMO Flexibility Ultra-lean design Support for higher spectrum Beam centric LTE single beam is a special case Better support of multi-trp/multi-panel transmission Key technologies CL-/OL-MIMO, beam management, CSI acquisition, RS design, QCL 7/26

8 Def: 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 8/26

9 L1/L2 beam management procedures for NR: P-1: initial beam selection P-2: TRP Tx beam refinement P-3: UE Rx beam refinement 9/26

10 A UE can be configured N 1 Reporting settings, M 1 Resource settings: Links between Reporting settings and Resource settings are configured in the agreed CSI measurement setting 10/26

11 Beam failure event: occurs when the quality of beam pair link(s) of an associated control channel falls low enough UE Beam failure recovery mechanism includes the following aspects Beam failure detection New candidate beam identification Beam failure recovery request transmission UE monitors gnb response for beam failure recovery request 11/26

12 Beam failure detection UE monitors beam failure detection RS to assess if a beam failure trigger condition has been met Beam failure detection RS: Periodic CSI-RS, FFS: SS block New candidate beam identification UE monitors beam identification RS to find a new candidate beam Beam identification RS: Periodic CSI-RS for BM, FFS: SS block Beam failure recovery request transmission Information about identifying UE and new gnb Tx beam FFS: beam failure recovery Tx options UE monitors gnb response for beam failure recovery request FFS: UE further reaction if gnb does not receive it 12/26

13 Number of CW per PDSCH assignment per UE 1 CW for layer 1~4 2 CW for layer 5~8 DL DMRS based spatial multiplexing 8 orthogonal DL DMRS ports for SU-MIMO 12 orthogonal DL DMRS ports for MU-MIMO DMRS based DL MIMO transmission schemes Scheme 1: Closed-loop transmission Data/DMRS using the same precoding matrix Scheme 2: Open-loop/Semi-open-loop FFS: Data/DMRS using the same precoding matrix FFS detailed schemes: SFBC, RB level precoder cycling, RE level precoder cycling 13/26

14 Both co-located and non-co-located TRP cases are considered Semi-static/dynamic coordination schemes E.g. DPS/DPB, CS/CB, coherent/noncoherent JT, eicic Coordination levels Centralized/distributed scheduling Delay assumptions NR support: DL transmission of the same NR-PDSCH data streams from multiple TRP with ideal backhaul Different NR-PDSCH data streams from multiple TRPs with both ideal and non-ideal backhaul FFS: CSI measurement and reporting, interference measurement schemes, resource scheduling,, etc. 14/26

15 DL Tx should consider Uniform/non-uniform array Coherent/noncoherent MIMO transmission Inter-panel phase calibration FFS: QCL aspect UL Tx: FFS: how to improve reliability and capacity for e.g. noncoherent Tx FFS: multiple timing advance, power control Consider inter-panel phase calibration 15/26

16 A UE can be configured with N 1 CSI reporting settings, M 1 Resource settings, and 1 CSI measurement setting (include L links) Support configurations to provide CSI similar to R14 efd-mimo hybrid CSI mechanism 1 and 2 M1: Class A+Class B K=1, M2: Class B K>1+Class B K=1 Support a common framework for BM and CSI acquisition 16/26

17 Aperiodic/semi-persistent/periodic CSI reporting are supported CSI reporting feedback type: Type 1: normal Codebook based PMI feedback with normal resolution at At least two-stage: W=W 1 W 2 CSI Reporting parameters: resource selection indicator (e.g. reference signal resource, port, reference signal sequence, beam), RI, PMI, channel quality Support multi-panel scenario with co-phasing across panels FFS: Wideband with/without subband co-phasing Type 2: advanced Explicit feedback and/or codebook with higher resolution CSI reporting granularity: Wideband Partial band Subband CSI 17/26

18 At least the following RS are supported for NR DL: CSI-RS: CSI acquisition, beam management DM-RS: data/control demodulation PT-RS: RS for phase tracking RS for time/frequency tracking RS for radio link monitoring RS for RRM measurement 18/26

19 NR supports periodic, aperiodic, semi-persistent CSI-RS NR CSI-RS pattern Can be mapped in {1,2,4} symbols FFS: detailed pattern Support CDM-2, CDM-4, CDM-8 For CSI acquisition, support density d RE/RB/port: At least d=1,1/2 Support PRB-level comb-type transmission NR CSI-RS configuration Include at least number of antenna ports Number of ports can be independently configured for periodic, aperiodic, semi-persistent CSI reporting A CSI-RS resource configuration up to 32 ports UE-specific configured CSI-RS to support wideband CSI-RS and partial band CSI-RS 19/26

20 For beam management overhead and latency reduction, NR supports sub-time units 1 OFDM symbol in a reference numerology. E.g. IFDMA/larger subcarrier spacing Larger SC spacing IFDMA 20/26

21 Support variable/configurable DMRS pattern FFS: detailed patterns At least, one configuration supports front-loaded DMRS pattern. mapped over 1 or 2 adjacent OFDM symbols At least for a slot, location of front-loaded DL DMRS is fixed regardless of the first symbol location of PDSCH Additional DMRS can be configured for the later part of the slot DL DMRS port multiplexing: FDM, TDM, CDM (OCC/CS) are considered DMRS bundling is supported in time domain At least for slot aggregation of DL-only slot DMRS pattern within the first slot is not impacted 21/26

22 Why NR needs PT-RS? Power of phase noise is considerably stronger in mmwave. PT-RS is supported for both DL and UL CP-OFDM same PTRS to RE mapping and PTRS densities in time and frequency are available for DL and UL UL DFT-s-OFDM waveform is also supported PT-RS pattern Support multiple PT-RS densities For CP-OFDM: time domain density: every/every other/every 4-th symbol Freq. domain density is associated with at least dynamic configuration of the scheduled BW Default configuration: Distributed PTRS (non-consecutive subcarriers) in the freq. domain PT-RS in scheduled resource are UE-specifically configured Presence depends on RRC configuration 22/26

23 Def: two antenna ports are said to be quasi colocated if properties of the channel over which a symbol on one antenna port is conveyed can be inferred from the channel over which a symbol on the other antenna port is conveyed QCL supports the following functionalities: Beam management (spatial parameter) Frequency/timing offset estimation (Doppler/delay) RRM measurement (average gain) RAN1 is currently on discussion about: QCL parameters and its corresponding RS, applications 23/26

24 Number of CW per PUSCH assignment per UE 1 CW for layer 1~4 The following are supported for data Tx: Codebook based transmission Freq. selective precoding for CP-OFDM when Tx ports X Non-codebook based transmission Freq. selective precoding for CP-OFDM when Tx ports Y Indication of DL measurement RS is supported for UE to calculate candidate precoder Diversity-based transmission schemes For DFT-S-OFDM, CDD, precoder cycling, antenna port switching, SFBC, and STBC can be the candidates 24/26

25 Dynamic switching is supported Rank determination is performed by gnb UL DMRS spatial multiplexing is supported SU-MIMO/MU-MIMO, Max. 4 layers for SU-MIMO 25/26

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