Demystifying 5G, Massive MIMO and Challenges 5G India 2017 Ramarao Anil Head Product Support, Development & Applications Rohde & Schwarz India Pvt. Ltd. COMPANY RESTRICTED
Agenda ı 5G Vision ı Why Virtualization & C-RAN? ı Why Massive MIMO? ı Challenges & OTA ı Summary COMPANY RESTRICTED
5G Vision: A Union of Spectral & Energy Efficiency Ultra-Dense Broadband Public Safety IoT Broadcast Mobility Radio: Spectral Efficiency Smart City Ecosystem Automotive E-Health Virtualization: Energy Efficiency Advanced test equipment bridging between radio & virtualization Both capacity and power consumption are critical for 5G success
Why 5G? Capacity vs. Revenue Increased Capacity, Increased OPEX Low data rates on edges BS Locations Optimal Network BS Locations Cell Edge Uniform Coverage Traffic? Traffic Voice dominated Expenses Voice dominated Growth Revenue Growth Revenue Expenses Time Mobile data explosion Mobile data explosion Time Drive profit by reducing expenses (energy efficiency)
Why 5G? Power Consumption Cellular Network Energy Consumption (China) Radio Access Network Energy Consumption 2G GSM 830,000 Basestations 80 GWH (96 KWH per BTx) 3G TD-SCDMA 350,000 Basestations 13 GWH (37 KWH per BTx) Air conditioners 51% 3% Equipment 46% O&M 21 % Electricity 41 % Site rent 31 % 7% Tx CAPEX OPEX WiFi Data Offloading 4.2 Million Access Points 2 GWH Power consumption 4G TD-LTE 800,000 Basestations 16 GWH (20 KWH per BTx) Biggest CAPEX/OPEX Expense is Air Conditioning CMRI, C-RAN: The Road Towards Green RAN, Dec. 2013 Example: China Mobile Network in 2013 consumed over 15 Billion KWH Source: IEEE Communications Magazine, Feb 2014
Cellular Infrastructure Evolution to 5G Passive Antennas & Separate Radio Transceivers Active Antenna System Antenna + Integrated TRx Traditional: 1G & 2G Distributed: 3G & 4G Centralized: 4.5G & 5G 0.45 to 1.9 GHz 0.7 to 3.6 GHz 3.4 to 6 GHz & 20 to 60 GHz 8 dual-polarized antennas 8+ dual-polarized passive antennas 128 to 512 active antennas Peak data rate: 114 kbps Peak data rate: 150 Mbps Peak data rate: 10 Gbps Massive MIMO: Requires new T&M paradigms
Energy Efficiency: C-RAN & Network Virtualization BS1: GSM Phy/Mac BS2: LTE Phy/Mac...... BS3: 5G Phy/Mac RTOS RTOS RTOS Hypervisor Centralized Control/Processing Centralized processing resource pool that can support 10~1000 cells Collaborative Radio Multi-cell joint scheduling and processing General Purpose Processor Platform Real-Time Cloud Target to open IT platform Consolidate the processing resource into a cloud Flexible multi-standard operation and migration Virtual Basestation Pool (Real-time Cloud BBU) High bandwidth optical transport network Clean System Target Less power consuming Lower OPEX Fast system roll-out -15% Capital Costs -50% Operating Costs -70% Power Consumption Architecture Equipment Air Con Switching Battery Transmission Total Traditional 0.65 kw 2.0 kw 0.2 kw 0.2 kw 0.2 kw 3.45 kw Distributed configurable wideband RRU Cloud Radio 0.55 kw 0.1 kw 0.2 kw 0.1 kw 0.2 kw 0.86 kw CMRI, C-RAN: The Road Towards Green RAN, Dec. 2013 Easiest way to improve energy efficiency: more virtualization
Spectral Efficiency: Why MIMO? Capacity (bits/second) Increased Capacity, Increased OPEX Number of Channels C = W N log 2 (1+SNR) Signal BW (Hz) Signal to Noise Ratio (S/N) Solutions: mmwave & Massive MIMO Use additional frequency bands in mmwave spectrum (24 to 110 GHz) for increased signal bandwidth up to 2 GHz Increase SNR of 5G waveforms and multiple access Implement Massive MIMO with multiple channels and beamforming to improve SNR
... Energy Efficiency: Why Massive? Wasted power PBS = 1 PBS = 0.008 Number of Antennas = 1 Number of BS transmit antennas (M t ) Normalized output power of antennas Normalized output power of base station 1 Number of UEs: 1 120 antennas per UE 120 Source: IEEE Signal Processing Magazine, Jan 2013 Improve energy efficiency: more antennas
......... Massive MIMO Beamforming Architectures Single Transceiver + Antenna Measurement equipment Probe p m th antenna Cm gm circulator or switch n th TRx module Receive RF chain Transmit RF chain Rn Tn From Analog...... To Digital... To Hybrid Analog Beamforming (ABF) Digital Beamforming (DBF) Hybrid Beamforming (HBF) x(t) N = 1 PA ABF Phase shifters Ant 1 Ant M x 1 (t) x N (t) DBF TRx 1 Ant 1 TRx N Ant M x 1 (t) x N (t) DBF Baseband beamforming Baseband beamforming TRx 1 TRx N ABF 1 ABF N Ant 1 Ant p Ant q Ant M N = 1, M antennas N TRx = M antennas N < M
Hardware Perspective: Massive MIMO = Beamforming + MIMO M = 4 Transceivers MIMO Array: M Data Streams Beamforming Array: 1 Data Stream x1(t) x2(t) x3(t) + x1(t) TRx x4(t) Massive MIMO: Combine Beamforming + MIMO = MU-MIMO with M antennas >> # of UEs Multi-User MIMO Increase SINR and capacity for each user i.e. UE1: 16 ant BF with 16x2 MIMO UE2: 32 ant BF with 8x2 MIMO Massive arrays of 128 to 1024 active antenna elements
Massive MIMO Challenges Data Bottleneck Calibration Mutual Coupling Irregular Arrays Complexity TRx CPRI Bottleneck RFIC RFIC FPGA Increased Costs Reduced MU-MIMO Reduced Capacity Grating Lobes Digital IQ Increased Costs
Active Antenna Arrays: The Calibration Problem RF Feeding Network Phase Shifter Tolerances Group Delay Variations Dynamic Thermal Effects in PAs RFIC RFIC Timing Errors in ADCs General Manufacturing Tolerances of Components & Thermal Effects FPGA LO Frequency Drift Between Modules Digital IQ Phase/Magnitude/Frequency Tolerances (Static & Dynamic)
Mutual Coupling vs. Network Capacity Problem: Antenna mutual coupling reduces capacity Solution: Measurement with multi-port VNA R&S ZNBT + 0.4λ 1.2λ Source: Signal Processing Magazine, IEEE, Jan 2013 In order to maintain capacity, square antenna arrays require more spacing to reduce antenna mutual coupling R&S ZN-Z84 0 to 8.5 GHz Up to 288 elements All S-parameters True simultaneous 24-port measurement
Massive MIMO = Complex Basestations Mutual Coupling Isolation Adaptive Self- Calibration Beamforming Architecture Wideband: PA and Filter Banks Receiver + DSP/FPGA mmwave = Non- CMOS components RFIC RFIC FPGA LO Clock Synchronization Fiber Transceivers Digital IQ Fiber Multiplexing Heat Dissipation 128 element AAS prototypes: Complexity increased by 8 times
Passive vs. Active Antennas: Why OTA? Input/Output: Radiated Signal Input/Output: Radiated Signal Passive Antenna Outer enclosure: Radome Front Radome Active Antenna Outer enclosure: Radome Antenna + Feeding Network Antenna + Feeding Network RF I/O ports Outer enclosure Input/Output: RF Signal Rear Radome/Heatsink RF Transceiver Boards + Filters CPRI + FPGA Board Shielding + Heatsink Outer enclosure Input/Output: Digital IQ BB Data
Basestation Field Distributions Basestation 8 Element Array at 2.69 GHz Far-field vs. near-field Far field magnitude Very near-field region (< 0.6m) Near-field region phase & magnitude Near: Phase + Magnitude Far: Magnitude Required chamber size for far-field AUT size (D) Frequency Chamber size 0.5 meters 6 GHz 10 meters 0.5 meters 30 GHz 50 meters 1.0 meter 6 GHz 40 meters 2D 2 / λ = 4.1 m
OTA Measurements for 5G Active & Passive Antennas Active Antennas Passive Antenna Measurements R&S ZVA Measurement Antenna R&S SMW200A Phase Shifter φ = [0, ± π/2, π] Active Antenna System DUT R&S ZVA Reference Antenna Frequency range: 0.4 to 110 GHz
Measurement Setup for 3D Antenna Pattern: 24 GHz DUT OTA measurements for R&D and sample testing in production Measurement Equipment Measurement Scenarios Shielded Chamber R&S DST200 R&S FSW Signal and Spectrum Analyzer R&S AMS32 Measurement SW
Benchtop Beamforming Measurements: R&S TS7124 Measurement Equipment R&S NRPM 60 GHz (and mmwave) will not have antenna connectors OTA measurements will be mandatory for production Shielded chamber (R&S TS7124) R&S TS7124 Vivaldi probe 27.5 to 75 GHz Measurement Scenarios RF antenna array beam forming/ electronic sector selection 2D Beam-Steering 3D Beam-Steering
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