- COOC2017 단기강좌 - 2017 년 6 월 7 일 ETRI 연구개발지원사업연차평가 (2 차년도 ) 1 5G & C RAN 전송용량저감기술 5G 를위한광액세스기술 광액세스기술 Indoor Analog RoF 기술 ETRI 연구개발지원사업연차평가 (2 차년도 ) 2
5G 광액세스망관계? 광통신? 3 5G?
5G Key Services Enhanced Mobile Broadband High data rate Low Latency Services (Ultra-high reliability/low latency Massive Internet of Things Massive connectivity Demanding conditions IoT 5G 5 5 5G Vision & Key Capabilities Key capabilities of IMT-2020 Inter relation between the three usage scenarios & Key capabilities Peak Data Rate 20 Gbps 100 Mbps User Experienced Data Rate Area Traffic Capacity 10 Mbps/m 2 3 Times Spectrum Efficiency Network Energy Efficiency 100 Times 500 km/h Mobility Connection Density 10 6 1 msec per km 2 (1 per m 2 ) (Radio Interface) Latency [Note] Each of the three usage scenarios does not need to meet all the Key Capabilities 6 6
모바일네트워크현안 EXABYTES PER MONTH GLOBAL MOBILE TRAFFIC GROWTH 30 25 24.3 57% CAGR 2014 20 16.1 15 10.7 10 6.8 5 2.5 4.2 0 2014 2015 2016 2017 2018 2019 (Ref: Cisco, Cisco VNI Global Mobile Data Traffic Forecast, 2014-2019 ) Subscribers in thousads Number of 4G mobile subscribers worldwide from 2010 to 2020 (in 1,000) 2,000,000 1,500,000 1,000,000 500,000 0 1,182 8,417 336,210 203,268 107,463 32,577 591,951 912,027 1,201,670 1,517,479 1,812,817 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 (ref: Jefferies & Company, Statistics 2015) Mobile traffic Growth: 57% CAGR (compound annual growth rate) 2015: 4.2 EB (Exa bytes), 2019: 24.3 EB (exa bytes) 10x traffic growth in next 5 years worldwide 4G LTE subscriber: ~$1.8 billion in 2020 (25% of world population) 5x growth in 5 years 5G prototype service in 2018, commercial service in 2020 7 Capex 사업자의수익정체 Revenue (ref: Infonetics, 2014 Market Size and Forecasts: WW, NA, EMEA, APAC, CALA ) (ref: Infonetics, 2014 Market Size and Forecasts: WW, NA, EMEA, APAC, CALA ) Mobile network Capex average Capex $35 billion (Y2014~Y2018) Revenue growth: 2% Big gap between traffic growth and revenue growth 8
C-RAN 기지국의진화 Conventional Architectures Cloud RAN Architectures Standard BS Traditional Site Site BBU Remoted Remote Head Site (RRU) Site BBU Centralized Intra BBU Pooling+CoMP Inter BBU Pooling+CoMP 3 cells (1 site) per BBU Phase 1 C-RAN 3 cells (1 site) per BBU Multiple site per BBU Phase 2 C-RAN Multiple site per BBU Multiple site per BBU Possible future Products Multiple site per BBU Future C-RAN Virtualized or vran Multiple site per BBU Multiple site per BBU Site 1 Site 2 BS Coaxial BS Radio BBU Radio Fiber BBU BS Radio Fiber BBU1 BS Radio Fiber BBU2 Fiber Fiber Fiber Central Office Fiber Fiber Fiber Central Office Switching Layer Backhaul Copper M-wave Fiber Backhaul Copper M-wave Fiber Backhaul Copper M-wave Fiber Backhaul Copper M-wave Fiber BBU1 BBU2 BBU3 Backhaul Fiber Backhaul Fiber Backhaul Fiber BBU1 BBU2 BBU3 Backhaul Fiber Backhaul Fiber Backhaul Fiber 참고 : OFC2015 Workshop Access Networks for High Speed Applications and Mobile Xhaul 10
Radio Access Network: Traditional Architecture ETRI 연구개발지원사업연차평가 (2 차년도 ) 11 Radio Access Network: C-RAN ETRI 연구개발지원사업연차평가 (2 차년도 ) 12
Capex/Opex Reduction Advantage of C-RAN(ref: http://www.fiercewireless.com/) 13 모바일용광인프라기술 국내 4G LTE 망에서는 C-RAN 구조의이동통신기지국이활용되고있으며, 인도어 DAS/Fronthaul 구간은디지털방식의광전송기술이주로사용 DAS(distributed antenna system) 인도어 DAS In-building DAS In-building DAS network network Fronthaul Backhaul 인도어 DAS 정의 : 건물내무선서비스제공을위해호스트장치에접속된공간적으로분리된다수의안테나네트워크 인도어 DAS 역할 : 다수의안테나를공간적으로분산시켜실내환경의높은트래픽용량문제와음영지역해소 인도어 DAS 기술현황 : 국내 4G망은디지털샘플링방식기반의광전송기술을적용한사업자별로독립된망을운용프론트홀 Fronthaul 정의 : C-RAN 구조의이동통신기지국에서 BBU (DU) 와 RRH (RU) 를연결하는광전송망을지칭 Fronthaul 역할 : 모바일가입자의음성및데이터를 RRU에서모아 BBU가위치하는전화국으로전달 Fronthaul 기술현황 : 현재국내 LTE 기반의 4G망에서는 CPRI & OBSAI 와같은디지털방식의광전송기술을적용 14
5G Key Technologies The Coming 5G ETRI 연구개발지원사업연차평가 (2 차년도 ) 16
Speed Limitation of Fronthaul C-RAN Radio units Digital Units Core network Mobile fronthaul Required data-traffics Type Data-rate Required data-traffic (CPRI-formatted) [1]2(antenna) x 30.72 Msps(sample rate) x 16 (bit/sample) x 2 (IQ) x 1.25 (8B/10B) = 2.45 Gb/s LTE (20MHz) 2x2 MIMO 0.15 Gb/s 5G (125MHz) 2x2 MIMO, 8FA 5 Gb/s 2(antenna) x 8(FA) x 184.3 Msps(sample rate) x 16 (bit/sample) x 2 (IQ) x 1.25 (8B/10B) = 117.95 Gb/s 5G (125MHz) 4x4 MIMO, 8FA 10 Gb/s 4(antenna) x 8(FA) x 184.3 Msps(sample rate) x 16 (bit/sample) x 2 (IQ) x 1.25 (8B/10B) = 235.9 Gb/s 5G (125MHz) 8x8 MIMO, 8FA 20 Gb/s 8(antenna) x 8(FA) x 184.3 Msps(sample rate) x 16 (bit/sample) x 2 (IQ) x 1.25 (8B/10B) = 471.8 Gb/s * [1] S. Cho et al, Cost effective Next Generation Mobile Fronthaul Architecture with Multi IF Carrier Transmission Scheme, OFC 2014 17 17 5G 를 위한 광액세스 기술 5G Vision from IMT-2020 Quadruple x1000 Latency Speed Less than 1ms 1000X 20Gbps) Capacity Energy 1000X Capacity/km2 ) 1000X Reduce 3GPP Family Technology Evolution GSM UMTS GPRS EDGE 1990 2000 Distributed-RAN HSPA HSPA+ LTE LTE-A 2010 2011 2014 Centralized (cloud)-ran Digitized RoF (CPRI, OBSAI, ORI) 2020? Cost-effective approaches for infrastructure will be very important 18
5G & C RAN 전송용량저감기술 5G 를위한광액세스기술 광액세스기술 Indoor Analog RoF 기술 ETRI 연구개발지원사업연차평가 (2 차년도 ) 19 5G Field Test 1
5G 를 위한 광액세스 후보 기술 Requirement Approach Solution Capacity Increase Large Capacity Transmission Data Compression Bandwidth Data Reduction Function Split New Technology Analog RoF Latency Fast Signal Processing 21 CPRI 기반 모바일 프론트홀 무선 장비 제어기(Radio Equipment Controller, REC)에서 무선 장비(Radio Equipment, RE) 사이의 기지국간 디지털 접속을 정의한 규격 CRPI 규격은 현재 버전 7까지 완료되었으며, 24.3Gbps (option 10) 까지 정의 광링크의 전송속도를 줄이기 위해 IQ data 압축기술이 연구 되고 있으며, 전체의 93.75% 를 차지하는 IQ data sample 을 대상으로 함. REC REC [CPRI Interface] [CPRI Protocol] 22
IQ Data Compression CPRI frame: IQ data (93.7% of total data), control, timing sync Requirement of IQ data compression Compression ratio: ~ 50% delay: < 20 s EVM degradation: < 3 % 1 st step: IQ Data Down-sampling 2 nd step: IQ bit width reduction I/Q bit width Original IQ data Downsampled IQ data Compressed IQ data time Data Compression Ratio: ~50% [CPRI Protocol Overview] BBU <IQ Data Compression> RRH 23 CPRI Compression Algorithms Algorithm Concept Pros & Cons 1 st Step Down sampling + : high compression quaulity & relatively low EVM degradation Non-linear quantization + : best in EVM degradation - : worst in FPGA logic utilization 2 nd Step Block scaling + : good in EVM degradation - : need a time for processing time Partial bit sampling MSB LSB Original signal b14 b13 b12 b11 b10 b9 b8 b7 b6 b5 b4 b3 b2 b1 b0 Lower-bit decimation b14 b13 b12 b11 b10 b9 b8 b7 b6 b5 Compress signal b14 b13 b12 b11 b10 b9 b8 b7 b6 b5 Decompress signal b14 b13 b12 b11 b10 b9 b8 b7 b6 b5 1 0 1 0 1 + : best performance for latency & FPGA logic utilization, relatively good in EVM degradation 24 24
CPRI Compression Requirements Requirements Standardization (ORI) Real Field (Telco needs) Compression Ratio > 50 % ( based I/Q data) 50 % ( based CPRI ) EVM degradation < 3 % < 0.5 % * One-way latency < 100 sec (preferably 20 sec) < 10 sec 25 CPRI Compression System VSG Software Developement Kit & Integrated Logic Analyzer FPGA board #1, #2 VSA SFP+ #1, #2 20km of SMF [ Photograph test-bed for IQ data compression/decompression ] 26
EVM degradation EVM degradation (%) 1.4 1.2 1.0 0.8 0.6 0.4 EVM = 0.70%, EVM = 0.55% Up/down+PB Up/down+BS Up/down+NL Simulation Experimental EVM = 1.64%, EVM = 0.16% EVM = 2.89%, EVM = 0.08% 0.2 0.0 0 1 2 3 EVM of input signal (%) [ Measured EVM degradation versus EVM of input signal, and constellation of 64QAM ] (PB: partial bit sampling, BS: block scaling, NL: non-linear quantization) 27 One-way latency 6.0 One-way latency (µs) 5.0 4.0 3.0 2.0 1.0 0.0 0 5 10 15 20 25 Transmission distance (km) Up/down+PB Up/down+NL Up/down+BS Speed Optimized Area Optimized [ One-way latency of additional compression+decompression ] 28
Function Split & Virtual Access Network 29 MAC/PHY 기능재분리를통한데이터저감 BBU (DU) RRH (RU) Upper Layer MAC OFDM PHY CPRI Framer/ Deframer CPRI Framer/ Deframer ADC Digital Signal Analog Signal 1.2~1.5 상대적데이터율 1 12 16 12 -MAC layer overhead -Extraction of User Data -Header Removal -8B/10B coding 참고 : Keiji Tanaka et al., Next-Generation Optical Access Networks for C-RAN, OFC 2015, LA 30
DU Function Split 및 종류 Trade off 31 Antenna Configuration and RAN Split 32
5G & C RAN 전송용량저감기술 5G 를위한광액세스기술 광액세스기술 Indoor Analog RoF 기술 ETRI 연구개발지원사업연차평가 (2 차년도 ) 33 5G Field Test 2
5G Access Options (BH/FH) Always use the available and lowest cost option if possible Transport Options for new 5G Access Points IP connection Dedicated optical fiber Optical PON XG_fast XG-cable mmwave point-to-point systems 35 Passive Optical Network (PON) No needs to use electrical power btw. central office and subscriber PON consists with OLT, ONT, and power splitter or WDM filter at Remote node 36
Sub-Channel CWDM Technology 37 Dual Sub-Channel/Multi Sub-Channel 38
Colorless Operation 39 NG-PON2 40
Incremental Upgrade (Pay-as-you-grow) 41 FSAN Standard Roadmap 42
100G-EPON timeline 43 100G-EPON 44
NG-PON2 vs 100G EPON NG-PON2 100G EPON Standard body ITU-T SG15 IEEE 802 Standard G.989.1,2,3 IEEE802.3ca PON capacity Dn: 4x10G (8x10G) Up: 4x2.5G (8x10G) Dn: 4x25G Up: 4x25G (or 10G) PtP WDM-PON Included Maybe not Max Capacity of ONU 10G / 2.5G 100G / 100G Channel bonding No Yes Wavelength Plan Dn: L+band, Up: C-band Not yet Tunable Yes No Co-existence G-PON, XG-PON 10G-EPON 45 100G EPON Homepage 46
25G PON 프로토타입 시험 실험 구성도 OE 상하향 성능 QoS 47 5G & C RAN 전송 용량 저감 기술 5G 를 위한 광액세스 기술 광액세스 기술 Indoor Analog RoF 기술 ETRI연구개발지원사업 연차 평가 (2차년도) 48
Indoor 5G 기술 * 참조: A global leader in infrastructure solutions for communications networks, CommScope 전체 Mobile Traffic의 80%가 Indoor 환경에서 발생 모바일 서비스(SNS 등)은 의사전달 수단에서 개인의 사회적 행동의 도구로 발전 현재는 Data 속도 저하 및 음영지역 해소 필요 Indoor 환경에서 25년 이상 사용되어 검증되고, 급격한 발전이 예상되는 solution은 DAS. 현재 DAS가 적용된 site는 수 만 국소 이상이며, 향후 2023년까지 약 1억 site로 증가 예상 49 49 현재의 디지털 DAS 기술 현황 디지털 DAS 구조 광트랜시버 광트랜시버 광케이블 호스트 장치 Radio 장치 디지털 DAS의 광전송 용량 증가 50
Bandwidth Efficient IFoF based Optical Access Digital Units RFoF ~ƒ c Mobile fronthaul ƒ c Digital Units IFoF ƒ 1 ƒ 2 ƒ n Mobile fronthaul Radio Units ƒ c Radio Units Type Radio frequency over Fiber (RFoF) Intermediate Frequency over Fiber (IFoF) Properties Transmission of mobile signal on the RF frequency as air interface through fronthaul link + Low implementation cost and complexity in RU - Requires many wavelength for increasing data-rate Transmission of mobile signal on intermediate frequency through fronthaul link + Bandwidth efficient transmission + Flexible bandwidth allocation - Increases implementation cost and complexity in RU 51 51 Millimeter wave 5G & indoor 밀리미터파 5G 이동통신시스템 기지국최대 20Gbps 단말 1 Gbps 아날로그 IFoF기반 Indoor DAS 최대 32 FA, 8x8 MIMO 지원 최대전송거리 5km, 최대 8 분기수용 5G 이동통신서비스음영지역해소 밀리미터파 5G 이동통신시스템신호사양 125 MHz x 8FA = 1GHz D-I/F Air: 1.7GHz 2.7G 27.5GHz 125 MHz 28.5GHz 52
5G 프로트타입 성능 시험 53 Analog Optical Transceiver LD Driver 0 S21 LD LNA S21 (db) PD -5 < ±1 db -10-15 -20 [Block diagram] -25 Recieved optical power : 0 dbm -30 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Frequency (GHz) [Frequency response] [Analog optical transceiver] 54
Measured Throughput per User @ UE Supporting giga-bit mobile service with 28 GHz mmwave 5G prototype Achieving peak data-rate up to 1.5 Gb/s per each user 55 55 Summary 1. 모바일 네트워크 현안 - 트래픽 폭증, 셀 소형화에 따라 비용 절감을 위한 새로운 망 구축/운용 기술 필요 - 광통신이 무한대의 대역폭을 제공한다는 선입관의 변화: 광액세스망 제한조건 2. 광 기반 모바일 인프라 기술 - 4G까지는 CPRI/OBSAI/ORI 표준 기반 전송 기술 및 기존 유선 인프라 활용 3. 5G 를 위한 광액세스망 기술 - 5G를 위한 다양한 프론트홀 후보 기술 대두, 대역폭 및 지연 성능 개선이 중요 - 100G PON, Analog RoF 기술등 새로운 기술 대두 56
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