2022年通信系统建模与仿真 2.pdf

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1、11Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-25西南交通大学Southwest Jiaotong University通信系统建模与仿真Modeling & Simulation of Communication SystemsIntroduction and Simulation ToolsPresented byProfessor Pingzhi Fan (范平志 ), PhD, SMIEEE西南交通大学移动通信省重点实验室Key Lab of Mobile Communications, South

2、west Jiaotong University四川成都，邮码：610031 ，Chengdu, 610031, PR ChinaWebsite: http:/ Email: p.fanieee.orgSeptember 2011 January 2012, ?SWJTU-IMC 20112Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-25CONTENTS1.Introduction and simulation tools2.Simulation of random variables and random

3、process3.Representation of signals and systems in simulation4.Simulation of communication channels5.Modeling and simulation of baseband and passbandtransmissions6.Modelingand simulation of OFDM/Multi-carrier transmission7.Modelingand simulation of CDMA transmission8.Modelingand simulation of multipl

4、e access protocols9.Estimationof performance measures from simulation3Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-25OutlineCourse requirements and policySystem modeling and simulation methodologySimulation tools and classificationNetwork simulation tools NS2, OMNeT+, etcGeneral

5、simulation tools SPW, Ptolemy, etc.Waveform simulation tools SystemView, Matlab, etcCourse assignment4Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-25Suitability and Coverage:The course is open to MScstudents majoring in communications and signal processing. The course covers fund

6、amentals in modeling and simulating various aspects of communication systems. Prerequisite: Communications principles and programming in C/C+ and Matlab.Grading Method: Grades are based on the following weights. Course Projects: 50% Homework and exam: 50% Final course gradingwill not be on an absolu

7、te cale.Students participation in and after class may affect the final grade. Coverage & Requirements5Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-25Homework Policy:Several written homework assignments will be given throughout the semester. These assignments will cover the readin

8、g and the class material. To be eligible for credit, each assignment solution must fulfill the published requirements and must be completed by the due date. Deadline Policy:All homework assignments will be given with a strict deadline, and students are required to submit their assignments on or befo

9、re the deadline. In case of extenuating circumstances, students are advised to contact the instructor assoon as practical. Conduct Policy:We pledge to hold ourselves and our peers to the highest standards of honesty and integrity. All assignments are to be considered an individual effortunless other

10、wise specified by the instructor. Students are expected to read, understand, and follow the honorcode rules as set forth by the university. Course Policy6Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-251. Hiroshi Harada, RamjeePrasad, Simulation and Software Radio for Mobile Commu

11、nications, ArtechHouse, 2002.2. Bernard Sklar, Digital Communications: Fundamentals and Applications, 2nd Ed., Pearson Education, 2002.3. Michel C. Jeruchim, Philip Balaban, K. Sam Shanmugan, Simulation of Communication Systems Modeling Methodology & Techniques, KluwerAcademic/Plenum Publishers, 2Ed

12、, 2000.4. F. M. Gardner, J. D. Baker, Simulation Techniques: Models of Communication Signals and Processes, John Wiley & Sons,1997.5. Averill M. Law, W. David Kelton, Simulation Modeling and Analysis, McGraw-Hill, 2000.6. Paul Burns, Software Defined Radio for 3G, ArtechHouse, 2003.7. MATLAB -The La

13、nguage of Technical Computing: Computation, Visualization, Programming, MathWorks, Inc. 2001.8. B.W. Schmeiser, Some myths and common errors in simulation experiments, Proceedings of the Winter Simulation Conf., 2001.9. ModelingSimu-1_Simulation software list.mht(list of simulation software)Referenc

14、e Materials名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - - - - - - - - - 名师精心整理 - - - - - - - 第 1 页，共 8 页 - - - - - - - - - 27Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-25Motivation: (1) increasing complexity makes the system implementation expensive; (2) new system design should be

15、 timely, cost-effectively and effort-free.System modeling, analyzing and designing: (1) Formula-based approaches, computer is used to evaluate complex formulas; (2) simulation-based approaches, computer is used to simulate the waveforms or signals that flow through the system. Simulation:imitation o

16、f a dynamic system using a model which accounts for system inter-dependencies & variability, in order to evaluate and improve system performance, and as close to the reality as possible. Simulation of communication systemsis concerned with imitating some aspects of the behavior of communication syst

17、ems by using modern computer software, without building the actual hardware.Introduction8Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-25Static vsdynamic simulation: static - not based on time; dynamic - include the passage of time, i.e. states are changed over time, clock mechani

18、sm moves forward in time.Deterministicvs stochastic simulation: deterministic -constant inputs/outputs (one run enough); stochastic -random inputs/outputs (multiple runs).Discrete-event v.s. continuous simulation: discreteevent - state changes at discrete (scheduled)timeand triggered conditionally b

19、y events; continuous- state variables changes continuously w.r.t. time(e.g. temperature controlled by heating system).Classification of SimulationMonte Carlo (a city which is the home of the world-famous casino):it basically involves the simulation of a random experiment using artificial means, i.e.

20、, without fully repeating the underlying physical experiment.9Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-25Simulation MethodologyMonte Carlo simulation implies that at least one random process is emulated and pure Monte Carlo implies all the input processes (sources, channels e

21、tc) are emulated which is time-consuming.Methodology: to “do”simulation efficiently and accurately. Tradeoffs are necessary between objectives, computing& manpower resources.Approximationsare necessary to reduce complexity or run-time:modeling level: simplification of the specific functionsperforman

22、ce evaluation level: estimation of performance measuresCommunication modeling:System Modeling- highest level of description; complexity reductionDevice Modelingblock or subsystem (e.g. transfer function on every clock cycle: input-transfer-output”)Random Process Modeling: (1) source random process (

23、imitated with pseudo random number generator RNG); (2) time-variant random channel; (3) equivalent random process (ERP).Modelingcan be physical, mathematical, discrete-event simulation (DES), etc. 10Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-25The major component of resolution

24、is the level of detail that the simulation can receive as input and return as output. If the resolution of a network model is at the packet level, then there is no information provided at the bit level. Bits submitted as input to the model cannot be processed unless the bits are collected and formed

25、 as packets prior to processing. The resolution of the output will be at the packet level unless an external synthesizing function of some sort is used to manipulate the output. The output will be produced based on the granularity of the simulation, but the output may be manipulated by an external f

26、unction which may change the granularity. Simulation GranularityINPUTconstantgranularitySIMULATIONgranularity no finer than inputOUTPUTsame or compositegranularity11Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-25Simulationroles: important role during all phases of the design and

27、engineering of communication systems, from early conceptual design through stages of implementation, testing, and fielding of the system.Simulation toolsfor communication system simulation:SPW (Cadence) Demo! Mentor- Demo!Cossap (CoCentric, Synopsys)EEsof EDA(Agilent)SystemC(SoC design in c/c+) SPIC

28、E (UC Berkeley)SystemView (ElanixInc.) Matlab (Mathworks)Mathematica(Wolfram Research) Maple (MapleSoft) SitePlanner(Wireless Valley)IT+(GPL, Chalmers, Sweden)OMNeT+(Free, AndrasVarga) NS2 (Free, UC Berkeley) Ptolemy (Free, UC Berkeley)SXD Coding (Free, SWJTU)Qualnet (commercial)http:/www.topology.o

29、rg/soft/sim.html, Simulation Tools12Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-25Simulation “Hierarchy ”NetworksLinksDSPCircuitsRFEvent driven simulations:ns2, OMNet+, OpnetTime driven simulations: SPW, Cossap, Simulink/MatlabAlgorithm simulations: TI CodeComposerPackets, messa

30、ges, flowsWaveforms, symbols(Our emphasis)Circuit simulations: NC-VHDL/Verilog, Scirroco, Implement.RF simulations: PSpice, ADS,XFDTD名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - - - - - - - - - 名师精心整理 - - - - - - - 第 2 页，共 8 页 - - - - - - - - - 313Southwest Jiaotong University, Chengdu, PR of China 西南交通

31、大学2011-8-25Discrete event simulation, event-driven.Process Packets, messages, flows, buffers, not waveform.Performance: throughput, response time, resource utilizationEstablish protocols, processors, object-oriented (C+, Tcl, etc)Free network simulators: NS2: Network Simulator, Omnet+, NETSIM (M.I.T

32、sNetwork Simulator), MaRS(Maryland Routing Simulator), LANSF(LocalArea Network Simulation Facility, Univof Alberta), SMURPH: System for Modeling UnslottedReal-Time Phenomena, Univof Alberta).Commercial network simulators: (1) general-purpose simulators: MODSIM, BONeSDESIGNER, GPSS/H, SIMSCRIPT II.5,

33、 SLAMSYSTEM, SES/workbench; (2) communications-oriented simulators such as BONeSPlanNet, COMNET III, L*NET II.5 and NETWORK II.5, OPNET Modeler.Network Level Simulation14Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-25Waveform Level SimulationSimulate waveform distortion effects (

34、nonlinearities, ISI), noise & interference.Time driven waveform level simulation is used typically to (1) generate sampled values of the input waveforms (processes); (2) process them through system models, and generate output; (3) estimate the performance by comparing inputs & outputs. Functional bl

35、ocks: modulators, encoders, filters, amplifiers, channels Performance: bit error rate, SNR, Simulators: c/c+, SystemView, Matlab/ Simulink, SPW, Cossap, 15Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-25Implementation Level SimulationSimulate, verify functionality, and characteriz

36、e the behavior of components by circuit simulator (Spice, etc) or digital simulator (HDL or VHDL).Need to specify area, speed, power, allows IF-THEN-ELSE, WAIT, UNTIL, FOR loopsfor IC design.Gate level or RTL(register-transfer-level) description is processed through synthesis toolset to create a lay

37、out, or bit stream for FPGAs.HW(Hardware) and SW (software) co-design is necessary.Validation & verification are important.Devices with 10 million gates are increasingly common with 0.13m tech.MentorGraphics, SPW, Xilinx, Spice,http:/www.eda.org/ModelingPerformanceEvaluationConversion UtilityVHDL(.v

38、hd file)Logic simulationLogicSynthesisLayout Place& RouteVHDL: VerilogHardware Description Language16Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-25Discrete Event Simulator, object-oriented (C+, OTcl), De facto standard for network simulationsPacket-level for wired and WirelessSc

39、alability + Extensibility: control/”data ”separation; C+ for data (per packet action); otclfor control (periodic or triggered action).Modular approach: (1) fine-grained object composition; (2) reusabilitySize (not current release) : 100K lines of C+, 70K lines of OTcl, 30K lines of test suites, 20K

40、lines of documentation.Applications: TCP behavior, Router queuing policies, multicast transport, Multimedia, wireless networking, Application-level (web cache etc) protocols. http:/www-mash.cs.berkeley.edu/ns/nsresearch.NS Network Simulator 17Southwest Jiaotong University, Chengdu, PR of China 西南交通大

41、学2011-8-25NS software package: (1) has implementation of wide variety of network protocols; (2) powerful analysis tools; (3) open sourced written in C+ and OTcl; (4) maintainability; (5) reliability.Example: Schedulingalgorithms- round robin; exhaustive; gated; globally gated; other priorities algor

42、ithms.NS Network Simulator 18Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-25C+ for “data ”: per packet actionOTcl for control: periodic or triggered actionCompromise between composibilityand speedLearning and debuggingOTcl and C+: Separation & DualityC+OTclPure C+objectsPure OTcl

43、objectsC+/OTcl split objectsns名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - - - - - - - - - 名师精心整理 - - - - - - - 第 3 页，共 8 页 - - - - - - - - - 419Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-25Bluetooth Scheduling ProblemOnce a master polls a slave, the next slot is reserved for the s

44、lave irrespective of whether the slave has data to send or not.Bluetooth uses TDDscheme:each slot is 625usec long; the master start transmitting only in even slots and slavesreply only in odd slots; packets aretransmitted in 1,3,5 slots.20Southwest Jiaotong University, Chengdu, PR of China 西南交通大学201

45、1-8-25ST = standby , I= inquiry , IS = inquiry scan , IR = inquiry response ,P = pagePS = page scan , SR = slave response , MR = master response , C = connectionBluetooth Scheduling Simulation21Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-25Dynamic TDMA SchedulerQuickly prototype

46、 algorithms Distributed algorithm Goal is to design conflict free schedule22Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-25Simulation of Ad Hoc Network?An ad hoc network is a collection of wireless mobile nodes that self-configure to form a network without the aid of any establis

47、hed infrastructure. Distributed control algorithms are necessary.?Ad Hoc Net Applications: tactical communication, disaster response, range extension for wireless LANs and cellular systems.23Southwest Jiaotong University, Chengdu, PR of China 西南交通大学2011-8-25Node Distribution14MACLayer0Total Noof Tim

48、e SlotsTraffic GenerationTraffic Complete ?SlotsMACLayerPHYLayer0i = 2012012i = 1Total Noof Time 14PHYLayer40Traffic Complete ?Total Noof Time Slots = kMACLayerPHYLayeri = knn-1nn-1Total Load0100 bits1100 bits2100 bitsn100 bits. . . . .Simulation of Ad Hoc Network24Southwest Jiaotong University, Che

49、ngdu, PR of China 西南交通大学2011-8-25OMNeT+ SimulatorAn object-oriented modular discrete event simulator: generate C+ simulation control code.Consists of modules that communicate with message passing: modules can be nested hierarchically; simple modules.Models are expressed in terms of a topology descri

50、ption language NED (NEtworkDescription).Module can have parameters to customize module topology, module behavior, and module communication. Applications: traffic modeling of telecommunication networks; protocol modeling; modeling queueingnetworks; modeling multiprocessors and other distributed hardw