5G Communications at mmwave Frequency Bands: from System Design Aspect

Transcription

1 5G Communications at mmwave Frequency Bands: from System Design Aspect Wern-Ho Sheen Department of Communications Engineering January

2 CONTENTS ITU-R/3GPP 5G Progress Taiwan s 5G Research Activities Key Propagation Characteristics at mm-wave Bands Ways of Using Large Antenna Arrays for 5G Beam-group Division Multiple Access (BgDMA): A mmwave 5G System for Enhanced Mobile Broadband 2

3 ITU-R Timeline for IMT Development and Deployment Vision Development of IMT-2020 Deployment(*) of IMT years 15 years Vision Development of IMT-Advanced Deployment (*) of IMT-Advanced Development of IMT-2000 Deployment (*) of IMT SQ Adopted FPLMTS IMT-2000 M.1457 (1 st release) Vision M.1645 IMT-Advanced M.2012 (1st release) IMT-2020 Vision IMT-2020 (*) Deployment timing may vary across countries. IMT: International Mobile Telecommunications Source: ITUR Document 5D/TEMP/548-E REV3, Feb

4 The 5G network is a key enabler for a fully mobile and connected information society in which information can be accessed by humans and machines anytime and anywhere. The access is characterized by highly diverse requirements on e.g. higher data-rates, lower latency, ultra-high reliability, higher connectivity density, and higher mobility range, while at the same time ensuring security, trust and privacy. The information society will empower socio-economic transformations not yet now imaginable, including productivity, sustainability and well-being. IMT-2020 is the name for 5G within ITU-R. 4

5 Source: ITUR Document 5D/TEMP/579-E, Feb

6 Usage Scenarios of IMT for 2020 and Beyond Source: ITUR Document 5D/TEMP/548-E REV3, Feb

7 Key Capabilities of IMT-2020 Source: ITU-R Document 5D/TEMP/625(Rev1)-E, June

8 3GPP 5G RAN Work Plan RAN#69 Sep 15 RAN#70 Dec 15 5D#23 Feb 16 RAN#72 Jun 16 5D#26 Feb 17 5D#27 Jun 17 5D#28 Oct 17 5D#31 Oct 18 5D#32 Jun 19 RAN#86 Jun 20 5D#34 Feb 20 5D#36 Oct 20 IMT 2020 Evaluation criteria Requirements Initial submissions of proposals Evaluation IMT-2020 specifications IMT 2020 requirements 3GPP requirements Initial 3GPP submission Final 3GPP submission RAN Workshop RAN SI: scope & requirements channel modeling RAN WG SI: evaluation of solutions RAN WG WI: specification of solutions HSPA/LTE evolution RAN#71 Mar 16 Rel-13 freeze Source: 3GPP RP , Getting ready for 5G, March

9 CONTENTS ITU-R/3GPP 5G Progress Taiwan s 5G Research Activities Key Propagation Characteristics at mm-wave Bands Ways of Using Large Antenna Arrays for 5G Beam-group Division Multiple Access (BgDMA): A mmwave 5G System for Enhanced Mobile Broadband 9

10 5G Research Activities in Taiwan Taiwan s 5G research and development plan is well aligned with that of international standard organizations such as ITU-R and 3GPP (3rd Generation Partnership Project). Currently, the plan is being carried out through various programs in MOST and MOEA (Ministry of Economic Affairs). MOST focuses more on the university side while MOEA more on the research institutes and industry side. Research Institutes: ITRI (Industrial Technology Research Institutes), III (Institute for Information Industry) Industry: MediaTek, ASUSTek, HTC, and Acer 10

11 Key Areas of 5G Research 11

12 Strategies for 5G R&D Rel-13 Rel-14 Rel-15 Rel-16 Rel-17 & Beyond LTE Evolution ( 演進部分 ) 技術重點 5G New Radio ( 全新部分 ) 技術重點 Q1 16 efd-mimo/comp Dynamic Beam-Cell ed2d for V2X emtc Multi-RAT Q2 17 LTE Enhancement for 5G Phase I 5G-eMBB Q3 18 Further LTE Enhancement 5G New Radio I: <6GHz Scalable up to ~40GHz (focus on embb) Forward Compatible 5G New Radio I: > 6GHz: 6 ~ 70 GHz Fully Compatible to IMT-2020 mmwave, Channel Modelling Beam Forming/Tracking Phased Array Antenna Pilot/Frame Design Dynamic UL/DL subframe OFDM, SC-OFDM, UAI, Dynamic Spectrum Access elaa, LSA Latency Reduction Signal Reduction Massive Connection UDN, virtual Cell Network MIMO C-RAN NFV Network Slicing Q1, G-Full (embb + mmtc + cmtc) 5G = LTE Evolution + 5G New Radio Source: 3GPP RAN Workshop on 5G, Phoenix, USA, September 17 18, 2015 ITRI 整理 Source: ITRI

13 5G Projects Sponsored by MOST New Radio Access Technology Research on 5th Generation Mobile Cellular Networks with Large-scale Active Antenna Systems An industry-academia collaboration project, aiming to design a new 5G radio access system, called Beam-group Division Multiple Access (BgDMA) A joint design and optimization of cellular architecture, antenna/ RF transceiver technology and basedband signal processing Development of Advanced Multiple Access Technologies for Wireless Communications NOMA (non-orthogonal multiple access) 13

14 Advanced wireless transmission techniques for ultradense small cell networks Cloud RAN, Network MIMO, COMP, interference mitigation Development of Full-duplex Radio Technology Backhaul application in UDN mmwave RF Transceivers and Antenna Technologies Millimeter-wave CMOS Transceiver Integrated Circuit and System-in-Package Technology Development Design of Advanced Millimeter Wave Antenna System Development of Multi-Beam Phased Array Antennas for Space- and Angular-Domain Diversities and their Dynamic Applications Dynamic Spectrum Sharing Enabling Technologies and Operation Models for Licensed Shared Access by LTE Services 14

15 CONTENTS ITU-R/3GPP 5G Progress Taiwan s 5G Research Activities Key Propagation Characteristics at mm-wave Bands Ways of Using Large Antenna Arrays for 5G Beam-group Division Multiple Access (BgDMA): A mmwave 5G System for Enhanced Mobile Broadband 15

16 Enhanced Mobile Broadband Key Capabilities User experienced data rate : Mbps Area traffic capacity: 10 Mbps/m 2 A contiguous bandwidth of a few hundreds MHz is widely regarded as needed. Channel capacity over AWGN channels S C BW log2 1 bps N I BW: Signal bandwidth S : signal power; N I noise plus interference power Such a large bandwidth is only available at high frequency bands 16

17 Channel Characteristics at mm-wave Bands High propagation loss r P d FSPL Free-space path loss 2 2 PG t tg r PG t tgr d 4 4 d t t r r P: Power at the input of transmit antenna t G G t r d : Gain of transmit antenna : Gain of receive antenna c f c PG G P d 4 d : Wave length; f : Carrier frequency c :Speed of light c d(meter) : Distance separates transmitter and receiver 2 17

18 Path loss comparisons Frequency 10 GHz 20 GHz 38 GHz 60 GHz NLOS Path Loss Exp Distance Meters NLOS Path Loss db LOS Path Loss db Delta db Link budget S = 23 dbm BW=500 MHz N = 174 dbm noise figure I = N I + N = 78 dbm = 81 dbm Source: ITUR Document 5D/TEMP/536-E, Feb

19 Example SNRs 19

20 Example SINR Small cell with high antenna gain is needed. 20

21 MCS vs. SINR (LTE) 10 0 Block Error Rate MCS0: QPSK, R = MCS1: QPSK, R = MCS2: QPSK, R = MCS3: QPSK, R = MCS4: QPSK, R = MCS5: QPSK, R = MCS6: QPSK, R = MCS7: QPSK, R = MCS8: QPSK, R = MCS9: QPSK, R = MCS10: 16-QAM, R = MCS11: 16-QAM, R = MCS12: 16-QAM, R = MCS13: 16-QAM, R = MCS14: 16-QAM, R = MCS15: 16-QAM, R = MCS16: 16-QAM, R = MCS17: 64-QAM, R = MCS18: 64-QAM, R = MCS19: 64-QAM, R = MCS20: 64-QAM, R = MCS21: 64-QAM, R = MCS22: 64-QAM, R = MCS23: 64-QAM, R = MCS24: 64-QAM, R = MCS25: 64-QAM, R = MCS26: 64-QAM, R = MCS27: 64-QAM, R = MCS28: 64-QAM, R = SNR(dB) 21

22 Smaller delay spread 28 GHz 38 GHz 60 GHz 73 GHz Mean RMS delay spread 23.6 ns 7.4 ns Max RMS delay spread ns 185 ns 36.6 ns ns Higher probability of blockage Source: ITUR Document 5D/TEMP/536-E, Feb

23 CONTENTS ITU-R/3GPP 5G Progress Taiwan s 5G Research Activities Key Propagation Characteristics at mm-wave Bands Ways of Using Large Antenna Arrays for 5G Beam-group Division Multiple Access (BgDMA): A mmwave 5G System 23

24 Antenna array model 2D Planar Antenna Array (3GPP TR ) Antenna array model represented by (M, N, P) 24

25 Antenna array model parameters 25

26 Patterns of antenna element Source: 3GPP TR V1.0.0 ( ) 26

27 Block Diagram for Data Transmission 27

28 Q n b for complexity/performance tradeoffs How the TRXU virtualization is to be done is the first key issue to be answered.. L Q for performance/complexity/signaling overhead tradeoff D min L, n u due to the limitation of the spatial degree of freedom The following effective channel matrix has to be known at enb for the optimal design of precoder P and selection of MCS. H = H V U eff txru n L n n n Q Q L u u b b It is not formidable for FDD systems due to a huge signaling overhead in the uplink. One common practice is to use codebook-based precoding. 28

29 Codebook: a set of precoding matrices known at both the enb and the UE denoted by W i, i = 1,, 2 L the receiver observes a channel realization, selects the best precoding matrix, and feeds back the precoding matrix indicator (PMI) to the transmitter 29

30 In the codebook-based precoding, the following effective channel matrix has to be known at UE for the selection of precoder W and MCS. H = H V U eff txru n L n n n Q Q L u u b b In LTE-advanced, a CSI (channel state information) report may include PMI, CQI (for MCS) and RI (rank indicator). How to design reference signals (RS) which can be used for the estimation of H eff is another key issue to be answered. 30

31 TRXU Virtualization TXRU virtualization model option-1a:sub-array partition model with 1D virtualization q = x w ; : Kronecker product The same TXRU virtualization weight vector is applied for all the columns K = M/MTXRU Option A) w is given by q x w 1 2 wk exp j ( k 1) dv cos etilt for k 1,..., K K TXRU m'=1 x w w 1 w 2 w 3 w 4 K q M TXRU m'=2 Source: 3GPP TR Option 1

32 TXRU virtualization model option-2a: Full-connection model with 1D virtualization w 1,1 W + K TXRU m'=1 + + q + M x q + M TXRU m'=2 + + Source: 3GPP TR

33 Block Diagram for CSI Reporting 33

34 CONTENTS ITU-R/3GPP 5G Progress Taiwan s 5G Research Activities Key Propagation Characteristics at mm-wave Bands Ways of Using Large Antenna Arrays for 5G Beam-group Division Multiple Access (BgDMA): A mmwave 5G System for Enhanced Mobile Broadband 34

35 Key Features of BgDMA Feature 1: Channel s frequency selectivity is resolved by a beam-domain processing along with delay compensation. Fixed beam-book, Ψ Ψ n T/R n b n T/R : number of RF transceiver units n b : number of antenna at enb The set of beams used by UEk, B k, can be found by a beam finding/tracking procedure. Delay spread is small over an individual beam. 35

36 Feature 2: More than one beam can be utilized simultaneously by a UE to obtain diversity/spatial multiplexing gains for SU-MIMO (single-user MIMO). 36

37 Feature 3: High-order MU-MIMO (multi-user MIMO) is achieved with a low-complexity beam-group based joint spatial division/multiplexing. A fixed beamformer for beam-group based spatial division Outer precoding for multiplexing users in the same usergroup (spatial multiplexing) 37

38 Summary of BgDMA Key Features 38

39 Summary of BgDMA Key Features (cont d) 39

40 Ray-Tracing Based Channel Moeling Wireless InSite A ray-tracing based simulation tool that provides results over a frequency range from 50MHz to 100GHz. Bern/Switzerland, CCU/Taiwan Configuration Antenna Height: enb (10m, 6m, 3m); UE (1.8m, 1.5m) Carrier Frequencies:10,20,30,40 GHz Ray parameters AOA,AOD, power, phase, delay 40

41 Bern/Switzerland 35 enbs with cell radius around 100m 3268 outdoor UEs (approximately 100 UEs per enb, uniformly distributed over the coverage area) Simulation area Reference: Google Earth Pro

42 3D map and UE distribution 42

43 3D map and UE distribution 43

44 Example rays 44

45 Example rays 45

46 Parameters Cell Architecture (ISD=200m) 35 base stations Values System Setup Number of UEs 3268 Carrier Frequencies f c (GHz) 10,20,30,40 Signal bandwidth (MHz) 500 Number 64,32 Antenna at enb (linear array) Antenna at UE Antenna spacing λ/2 Height(meter) 10 Number 1 Pattern Height(meter) 1.8 Transmit Power (dbm) 23 Beambook N(dBm) Type Number of Beams, N B 17 C Noise Figure(6dB) Omni-directional DFT-based 128, 64 Power Threshold for Examined Rays (dbm) -140 SINR Threshold for Detectable Beams(dB) -15 SINR Threshold for Outage(dB) dbm = -81 dbm 46

47 Outage probability P out = P r SNR < 6 db 47

48 Uplink Performanvce (Single-User) Delay Spread (1/2) x%-power delay spread Beam set selection: power loss less than 0.5dB j B 1, j 10 log10 Pi 10 log10 Pi 0.5 db i 1 i 1 : the set of detectble beams, i P P, i j i j 48

49 Delay Spread (2/2) 49

50 Number of Beams in a Beam Set 50

51 x = log SNR bit/s/hz Achievable Rates(1/2) k beam: k largest beams in the beam-set 51

52 Achievable Rates(2/2) 52

53 Beam Finding and Tracking Single-subcarrier beam finding reference signal Multiple-subcarrier beam finding reference signal reference signal reference signal 53

54 Simulation routes 54

55 Extra beams found by multiple sub-carrier beam finding number of beams in a beam set Extra beams found probability by multiple subcarrier beam finding

56 Performance loss due to less frequent beam finding/tracking 56

57 Thanks!! 57