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Asier Alonso Muñoz Intelligent Transport Communication Networks Researcher TECNALIA-TELECOM. SDR Based Methodology for On-Board Communications Systems Design. The next “big thing” ?. V2V R2V I2V V2U. EFFICIENCY. SAFETY. NAVIGATION & TRACKING. COMFORT & INFOTAINMENT.
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Asier Alonso Muñoz Intelligent Transport Communication Networks Researcher TECNALIA-TELECOM
SDR Based Methodology for On-Board Communications Systems Design
The next “big thing” ? V2V R2V I2V V2U EFFICIENCY SAFETY NAVIGATION & TRACKING COMFORT & INFOTAINMENT
Probably!, but some challenges still unsolved • Many radio standards forced to coexist on board, integrated in a single device !? • Time mismatch between cars and communication equipment lifecycles • Radio standards not fully harmonized worldwide
Our motivation To find an innovative design methodology for on-board (and infrastructure) devices which enables multiple radio integration To define a reconfigurable system architecture which enables seamless evolution towards new communication standards To design a new signal processing algorithm which, making use of new acquisition techniques, allows reducing the number of Hw components
… and here it comes SDR ! • One device per One single device waveform integrating multiple radios • Many Hw components Single programmable device (FPGA, DSP) Amplifying + Filtering + Downconverting Traditional SDR platform scheme
What SDR provides… • Different waveforms in a single device • Multiple standards integrated • Costs dramatically reduced • Manufacturing, logistical support and operating expenditures • Reconfigurability and upgradability • New standards, features or capabilities added • Over-The-Air (OTA) reprogramming • Lifecycle mismatch reduced customer satisfaction improved • Specific location-based Sw loads • Addressing regional/national requirements
Configuration Unit External Interfaces General General General PROM PROM PROM JTAG JTAG JTAG purpose purpose purpose Ethernet Ethernet Ethernet USB USB USB I/O I/O I/O Processing Unit Clock Mgmt Unit Memory Elements Processor Distributor Clock Oscillator RAM Unit Signal Processing Ext. Memory Card Acquisition Unit Digitization Parts (ADC/DAC) Digitization Digitization parts parts (ADC/DAC) (ADC/DAC) RF Front End RF RF Front Front - - - end end SDR-based On-Board Hw Architecture
Receiver Front-End LNA ADC BPF Signal Processing • Digitization in SDR systems is made: • In theory, just after the antenna • In practice, after the RF front end • This adds limitations regarding flexibility • A possible solution direct digitization • Choice of an appropriate sampling frequency • Digital front-end design
Sampling Frequency Choice • Bandpass sampling allows supressing analog downconversion from the RF front-end, but it requires: • Careful study of the appropriate sampling frequency • Analysis of the generated spurious signals • Two main benefits: • Bandwidth reduction for acquiring multiple signals • More flexibility
Sampling Frequency Choice (cont’d) • Example: GNSS signals GPS (L1) & Galileo (E5a/b) Full Bw = 400 MHz
Sampling Frequency Choice (cont’d) • Final frequency after aliasing is: • Our goal was to match Galileo and GPS central frequencies so we obtain: Fal = M*Fs± Fo -N*Fs+FGPS=M*Fs-FGal
Sampling Frequency Choice (cont’d) 7 possible sampling frequencies : Final Bw = 60 MHz
Digital Front-End Design • Each GNSS signal is processed independently • Each band is processed with a standard downsampling scheme
Results • Two ways of studying the behaviour of the system: • Preliminary Simulink/Modelsim analysis chosen sampling frequency = 153.7MHz • Laboratory tests measuring of dynamic range (main drawback of direct digitization)
Results (cont’d) • Dynamic range tests: If signal power decreases undesired spurious signals Dynamic range = 40 dB = ADC’s DR
Conclusions • The three proposed objectives have been met: • Choosing a new paradigm of design for reconfigurable systems SDR • Designing an architecture for on-board devices Generic open platform • Finding new signal processing algorithms which can reduce the number of Hw elements Digital Front-End for Direct Digitization
Next Steps • Designing a flexible analog front-end which allows working with different real signals • Research on algorithms which allow dynamic reconfiguration of the system
Thank you ! Asier Alonso Muñoz Intelligent Transport Communication Networks Researcher TECNALIA TELECOM aalonso@robotiker.es www.tecnalia.es/telecom www.robotiker.es
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TECNALIA Telecom Business Unit of TECNALIA for the Telecommunications Sector • TECNALIA Telecom develops its activity in the following Research Fields: • Broadband Networks • Wireless Systems • Mobile Service Platforms • TECNALIA Telecomprovides: • Joint collaboration in Pre-competitive, Public-funded projects • Contract based Research and Development Projects • IPR and Research assets (Products & Technology) • New exploitation routes for innovation: spin-ins, spin-offs, joint-ventures, etc.
Telecom – Wireless Systems Intelligent Transport Communication Networks Group • Within the Wireless Systems Research Area, the Intelligent Transport Communication Networks Group specializes in communication technologies for transport/vehicular environments, focusing its activity in applied research for V2X in: • On-board system optimisation (OBUs, in-vehicle comms – CAN, BT, UWB, NFC, RFID) • VANET networks and devices (WAVE, 802.11p, IR, ZigBee) • Cooperative systems for road transport • Broadcasting (DAB, DVB-H, SDR) • Network architectures (3G, WiMAX, Ad-Hoc, routing) • GNSS technologies (GPS, GALILEO, EGNOS) and indoor guidance • Facts & Figures: • Research Team: 1 Group Leader, 6 Researchers, 1 PhD Researcher • R&D Assets: OpenGNSS, OpenGNSS Lite, OpenSDR, eOBU • Public Funded Research Projects: CYBERCARS2 (FP6), MOBILIZING INTERNET (ITEA), MARTA, mVIA, NCV2015 (Spanish Programmes), INCAVE, i:MUGI (Basque Programmes)