Base Station RF with MATLAB Dr Chen Ming Shanghai Bell Co., Ltd. 2015/04/24 1 2015 The MathWorks, Inc.
Agenda Background MATLAB Applied to Base Station RF Testing and ion Q&A 2
Shanghai Bell Co., Ltd. One of 112 central enterprises under SASAC oversight, and China's first foreigninvested joint-stock company in high-tech field Alcatel-Lucent's global flagship enterprise Domestic sales and service network covering 31 provinces International operations in over 50 countries and regions, overseas sales accounted for about 50 percent of total revenue Number of employees: approximately 11,000 people (including 6,000 R & D personnel, with more than 65 percent masters or PhD) 3
Speaker Introduction Chen Ming PhD in Communication and Information Engineering, University of Science and technology of China Shanghai Bell System Consultant Engineer Responsible for wireless system design and wireless baseband and RF algorithms in R&D. Core member of the successful development of a variety of wireless products, with 15 years of research and product development experience in 3G / 4G wireless systems and RF fields. As leader of algorithm/fpga/dsp team in RF hardware department. 4
The Base Station RF system - RRH Remote site RRH Local site optical fiber The base station radio system converts information between baseband and radio frequency (RF) electromagnetic signals The base station system includes digital/if/rf, with mixed-signal components, RF power amplifiers, and duplexers (switches) 5
Digital IF Filter Design Cosim with SW and HW Digital IF is the core system of the RF base station The main algorithm functionality: Multi-rate filter, PAPR suppression, digital predistortion, transceiver channel equalization, IQEC etc 6
Challenges Broadband Amplifier ion PA characteristics When power amplifier is working efficiently, output is distorted PAPR is high for 3G / 4G signals Backed-off power amplifier efficiency is very low Nonlinear response will lead to : In-band signal distortion Adjacent Channel Leakage * Simplified no memory model How to get high efficiency and low distortion? 7
No Digital Predistortion ion Spectrum before PA Spectrum after PA 8
Output power Digital Predistortion ion Spectrum before Predistortion Spectrum after Predistortion Spectrum after PA PA Input power 9
Platform ion Agilent MXA Agilent MXG AR 60W Amplifier Directional Coupler Circulator 500 W PA Circulator 40 db Attenuator Directional Coupler Sensor 50 W 50 W Sensor MATLAB Agilent Power Meter 10
Combined HW and SW platform for Verification ion RF Power Meter Spectrum Analyzer Signal Generation MATLAB Base Station Power Amplifiers High Power Amplifier 11
Tuning Parameters ion CP spectrum Use MATLAB modelling for PAPR suppression algorithm (CFR) By traversing the various parameters, tune an optimal combination of parameters dbr 0-50 data PSD + pulse spectrum -100-20 -10 0 10 20 f MHz CCDF's 0 log10 probability -2-4 dbr EVM % 0-50 PSDs at lowest PAR target -100-20 -10 0 10 20 f MHz EVM vs PAR (upsampled) 12 11 10 Magnitude (db) Magnitude (db) 0 L5M-4*20 L5M-FDD -10 L10M-4*20-20 L10M-FDD L15M-4*20-30 L15M-FDD -40 L20M-4*20 L20M-FDD -50-60 -70-80 -90 0 50 100 150 Frequency (MHz) CP spectrum L5M-4*20 0 L5M-FDD L10M-4*20-20 L10M-FDD L15M-4*20 L15M-FDD -40 L20M-4*20 L20M-FDD -60-6 0 5 10 PAR db 9 5 6 7 8 PAR db -80-100 0 2 4 6 8 10 12 Frequency (MHz) 12
Filter Design ion MATLAB / Simulink to build a prototype algorithm Using Altera DSP Builder & Xilinx System Generator for fast FPGA algorithm design 13
Generating a Test Signal ion Design, Simulation, Test of LTE / LTE-A system Simulation of all LTE / LTE-A modes, channels, and signals LTE Release 8 to Release 11 LTE Baseband simulation models and RF models Generate LTE test signals Foundation for 4/5G development 14
Generating a Test Signal ion MATLAB LTE waveform generation Signal Processing Visualization E-TM Generator APP Input Signal Description : PAPR = 9.9 db TM 3.1 Bandwidth ~ 20 MHz 64 QAM 30.72 MHz Sampling Rate 15
Phase ion Use UVM for digital IF full link simulation MATLAB provides golden reference model 16
Controlling Instruments, Expanding Instrument Functions ion RF Signal Generator LAN/USB/GPIB Signal generation Generate a baseband signal in MATLAB Download to signal generators to transmit as radio signals Spectrum Analyzer LAN/USB/GPIB Signal Analysis Acquire a wireless signal using a spectrum analyser Upload to the PC for MATLAB analysis 17
Sharing Results? Collaboration Across Divisions ion Suppliers MATLAB User Clients Organization Group Members Collaborator s Generate an executable file with the MATLAB Compiler Distribute to production departments.exe MATLAB Compiler.dll MATLAB license not required Cost savings on instrument purchases 18
Q&A 19