Scilab/Scicos toolboxes for Telecommunications

1. Scilab/Scicos toolboxes for Telecommunications Sebastien Mons, Alan Layec*, Abderrazak. Benadji, Tibault Reveyrand, Raphael Sommet, Edouard Ngoya, Raymond Quéré. XLIM/C2S2 – Université de Limoges, 123 av. A. Thomas, 87060 Limoges, France *INRIA –Domaine de Voluceau-Rocquencourt, B.P. 105, 78153 Le Chesnay Cedex, France e-mail : sebastien.mons@xlim.fr

2. Outline • XLIM Laboratory • C2S2 department • Scilab/scicos environment, why this choice ? Toolboxes developed • Advanced Device simulation • Advanced Circuit-system simulation • Measurement test set-ups Conclusion Information to prepare a Phd at our laboratory

3. XLIM Laboratory Limoges (ESTER) Limoges (FST) Brive (IUT) 5 Research Departments Department of Mathematics and Informatics (DMI) : Synthesis of Realistic Images, formal calculation, modeling, dynamical optimization, arithmetic, code, cryptography Waves and associated systems (OSA) Multifunction Antennas. WirelessNetworks, Waves and Health Electromagnetic compatibility, Ultra-Wideband Impulse Devices. MIcro-NAnotechnologies for Optoelectronical Components and Microwaves Multifunction Antennas, MEMS and Ceramic Components, Optoelectronic, organic Micro-Nanotechnologies. Modeling Tools. Photonic(PHOTONIC) New Generations of Optical fibers, Architectures of Optical and Lasers Amplifiers, Interferometric and Biophotonic Instrumentations, High-speed Optoelectronic. Components – Circuits - Signals and Systems High Frequencies(C2S2) TelecommunicationsSystems, Power amplifiers, Oscillators fréquency generation, Low-noise functions, Advanced Simulation, Advanced Instrumentation XLIM

4. Platform of Technologie and Instrumentation (PLATINOM) Transverse Programs : Security and reliability of the Information systems TeraHertz Radar and Optics Imaging • Human Resources • 174 professors, researchers, post doctorands… • 156 PhD students, 34 students • Scientific Production (2002-2004) • 94 thesis 75 articles and invited communications • 17 contribution to works 296 international Communications (with proceedings) • 175 international reviews 188 national reviews and communications • 14 patents Components, circuits, antennas Set-ups (Telecommunication - radar systems) Technologies for Optical fibers and micro-nanosystems

5. C2S2 DepartmentChips – Circuits - Signals and Systems High Frequencies Manager : Raymond QuéréContact : raymond.quere@xlim.fr Human resources :30 professors, researchers… 42 PhD students, 7 master’s degree students 6 Research Projets : Telecommunications Systems micro-optoelectronic components, Architectures, links Simulation Low-noise functions integrated adaptive filtering Design methodologies Recieved integrated systems Technologies (GaAs, Silicium, SiGe) Power amplifiers Smart power Architectures Design Modeling (nonlinear, Thermique, …) new technological process (GaN, InP, …) Oscillators fréquency generation Architectures Conception Modeling (NL,Noise,…) Chips (GaAs, SiGe, InP,…) Instrumentation PLATINOM Advanced Instrumentation Advanced Simulation Top Down Design Bottom Up Analysis AmCAD Engineering MITIC : Common Laboratory Thales/XLIM Xpedion Design Systems Agilent Technologies

6. RFfront-end simulation problematic : compromise accuracy / time consuming… Top-down process System architecture synthesis Device architecture dimensioning Hamonic Balance, Time Envelope Data-flow analysis Bottom-up analysis Top-down process : use of accurate simulation tools to decrease margins taken on components specifications Bottom-up analysis : behavior-modeling predict and analyse the impact of microwave components on “system” performance Cost reduction is a key issue for the development of the next generation of suchs systems

7. System complexity  Hierarchic decomposition Sub-system Physic Thermal Mechanical Electro-magnetic Electrical Take into account of different physics-based aspects ? chip Linked to measurements setup ? function Circuit System level Cope with different kinds of formalisms and simulators ? circuit level Component component level

8. Scilab/Scicos environment • Why this choice? • Available tools do not fully correspond to our needs • Scilab/scicos provide a powerful open computing environment for scientific applications • Solution : Integration of a number of tools in the highlevel Scilab/Scicos environment Advantages • Offers free and powerful numerical computation capabilities • An open and extensible computing environment (C, C++, Fortran...) • High and low level graphical subroutines for post-processing • Many available various "toolboxes" • Powerful linear algebra libraries such UMFPACK, ATLAS, ARPACK,TAUCS... • Easy to interface existing simulators • Possibility to perform parallel tasks (PVM,...)

9. Instrumentation LSNA (system) LSNA (pulsed) I-V [S] Measurement test set-ups links (GPIB) Telecom system simulation functions Physics ADS (Agilent Technologies) Scicos Thermals cosimulation API simulators models order reduction simulation Modeling Elm Golden Gate/ LISA (Xpedion-XLIM) circuits Organisation of Researchtools Key points Allow mixed simulation (event, discrete and continuous) Models adopted for analog parts keep the notion ofsignal/information physics based variables (power, energy, currents, voltages,temperature) Cosimulation systems/circuits/devices Very large system simulation multi channel systems Computation of low Bit ErrorRates

10. Thermal Simulation Circuit simulation Drift diffusion equations 1 – Advanced device-circuit simulation 1.2 – HBT/Circuit Simulation (R. SOMMET,Z. RIAH) • Direct coupling between • Physics-based simulation (HBT) • Circuit Simulation • Reduced thermal model • Noise simulation capabilities

11. 1.2 – PIN diode Simulation (thesis E. Gatard) • A physics-based simulation of the diode impedance • Based on the Ambipolar equation • Recombination in the heavy doped region are taken into account

12. Finite Element Software 1.3 – Model Order Reduction of thermal problem FEM (ANSYS) System of n ODEs ( ≈ 100000) MOR (SCILAB) Reduced System of r <<n ODEs (< 30)

13. 90° 90° Pure analog Segment QPSK modulator QPSK Demodulator Pass Band Filter Source coding Channel coder ADC PA LO LO Duplexer LO LO 1 Source Decoder Channel Decoder QPSK Demodulator Pass Band Filter LNA DAC Pure digital Segment 2 – Advanced circuit-system simulation 2.1 - MODNUM : for the modeling /simulation of communication systems (Alan Layec thesis) Analog circuits (PA, LNA, antennas, filters…) Digital circuits (source, channel coders/decoders…) Mixed circuits (Digital converters, modulators, local oscillators…) Communication chain Scilab/Scicos is used for interaction between analog circuit and pure digital circuits

14. Contents Modnum is 71 scicos blocks Scicos Diagram, Scilab scripts linux / windows platform Documentation (pdf/html) • Base -band PSK/QAM modulations : • Blocks • Schematics • in-line functions • Spread-spectrum Components : • Pseudo Noise sequence generators • (Quasi-Chaotic, PN, Gold sequence …) • Miscellaneous scopes for Scicos : • 3D trajectory, • Eye Diagram, • Scattered Diagram… • Frequency synthesizer components • Phase/Frequency Detector, • VCO, • Delta-Sigma modulators,... • Chaotic systems schematics : • Chua's, • Rössler's, • Van Der Pol's systems,… • . Toolbox organization

15. Running simulation from scilab promptis possible with the "scicos_simulate"function : [Info]=scicos_simulate(scs_m,Info,%ctxt) • Parametrized simulations. • Post processed operations (FFT,...) Results list Context list Main data Scicos structure Simulation in batch mode Simulations with PVM • BER at 10-7 (at least 100 errors) • For 1 processor (2GHz) : 300 h of computation !!! • Ideas to reduce the time computation of BER : • break the long sequence • use several CPU to realize the simulation • Scilab interfaced function of Parallel Virtual Machine System enablescommunication between distant session.

16. Screenshots Chaotic sub-system PSK chain transmission Synthesizer

17. 2.2 – Circuit-system interaction : cosimulation / macro-models implementation (Abderrezak Bennadji thesis) Cosimulation : direct communication between circuit and system simulators  High level of precision CPU time  • Behavior models : • reduced image integrating the circuit simulation concepts • dynamic of the circuit (memory,…) • Interactions between circuits (mismatches) • able to run indifferently with TE/ HB solvers  Good level of precision CPU time 

18. ~ Y(t) find Behavior modeling principle simulations Black-box representation  ? ~ x(t) y(t) X(t) Complex Topology characterizations Objectives : Take into account Inter-stages mismatches, Nonlinear memory effects… Models developped for PAs: • Volterra Model • Nonlinear Impulse Response Model • Modulated Volterra Model

19. Modeling principle : Two data processing modules Characterization Procedure Data extraction C++ language Module 1 Simulations Data processing header file Calculation of the filters’ coefficients .dat .head Measurements Header file .head Module 2 Re Re Execution of the model in Scicos Im Scicos block Im y=f0(u0, u1, u2, … )

20. Circuit/System coupling Method : cosimulation principle To improve modeling accuracy a Co-simulation interface At every activation of the block, the following tasks are achieved : • Launching the circuit simulator for the execution of the envelope simulation, this simulation can contain several steps of analysis. • To return the simulation results to the system simulator. System simulator (Scicos) Amplifier Circuit Simulator (GoldenGate ) Amplifier IPC Interface OL Bidirectional Communication

21. Applications : models vs circuit simulation AM /AM AM/PM Model Volterra Model Impulse response Model Co-simulation 70 Simulation 16 QAM LNA BiCMOS L Band ACPR Curve @ 5 MB/S 60 50 ACPR (dB) 40 30 20 -22 -18 -14 -10 -6 -2 0 Pin ( Pin ( dBm dBm ) ) Co-simulation Volterra Model AM/AM AM/PMModel Impulse response Complete chain simulation time 2 min. 23 sec 14 sec 2 min. 18 sec 1h. 12 min

22. 3 – Measurement test set-ups Use of the GPIB toolbox… Easy to modify, no compilation needed, possible link with scicos simulator

23. Example : Two test setups fully automated with scilab… Frequency domain test setup Time domain envelop test setup (modulated signals ) • Specific instruments : • arbitrary waveform Generator, • sampling digital oscilloscope • characteristics : •  1 GHz - 4 GHz • Modulated band pass : 125 MHz • Power : 10W RF • Interests : • Memory effect characterization • Measurement basis for system modeling • Study of linearisation techniques • validation of PAs models. • Specific instruments : • Pulsed generator, VNA, automated Tuner, • actives loops, scopes, probe station. • characteristics : •  1 GHz - 26,5  GHz • Multiharmonics • Power 10W RF • Modes : CW , pulsed CW and 2 tones • Interests: • Transistor characterization, PAE, Pout IM3,…, • validation of transistors models • automatic search of optimal loading impedance

24. Conclusion Faster and more accurate system level simulations chain is more and more important in modern system design. • AESA-Radar, • Telecommunication • Laboratory strategy : federate different tools within a system level hierarchic design framework • Scilab/Scicos is an efficient tool for high frequency device, circuit and system simulation. • 2/3 toolboxes presented are open-source, freely usable Support

25. Useful addresses :the university of Limoges welcomes you… University of Limogeshttp://www.unilim.fr Reception Office of the international students (BAEI) To answer your questions about : • Lodging • Administrative formalities • Transportation • Opening a bank account • The student health plan • Discovering Limoges and its region Phone : +33(0) 555 149 085Mail : accueil.international@unilim.fr

26. to integrate the university course … http://www.sciences.unilim.fr/ to prepare a master of Research … STIC (Communication and Information Sciences and Technologies ) • Mathematics, Cryptography, coding, calculation thierry.berger@unilim.fr • Data Processing, Information Sciences and Communication plemenos@unilim.fr • Circuits, Systems, Micro and Nanotechnologies for the communications high frequencies and optics vaudon@ircom.unilim.fr …. more information on http://www.sciences.unilim.fr/edsts • Formation, master of Research, course of Language, thesis, laboratory, useful links … Join our laboratory to prepare a thesis… • Subjects of thesis (26 suggested for the year 2006) • Fellowship scheme  • Presentation of the departments of Research • Contacts http://www.xlim.fr