Presentation on theme: "Simulation of communication systems (DT001A)"— Presentation transcript:
1 Simulation of communication systems (DT001A) Welcome toSimulation of communication systems (DT001A)and
2 A project course about MATLAB with SIMULINK and Communications Blockset… MATLAB = Matrix Laboratory.Tool for numerical calculation and visualization. Commonly used for simulation of the communication system physical layer, signal and image processing research, etc.SIMULINK: Toolbox in Matlabthat allows graphical data-flow oriented programming.
3 …and about Network Simulation using tools such as Opnet, NS/2, etc
4 Aim of the courseTo prepare the student for thesis project and work in the area of telecommunciations development and research.To give experience of performance analysis of communication systems and algorithms, at the physical layer and datalink layer.To give experience of simulation tools such as MATLAB, SIMULINK and/or Opnet.This may include modelling and simulation of traffic sources, channel models, modulation schemes, error coding schemes, equalizers, algorithms, protocols and network topologies.A real-world project is studied within an application area such as wireless sensor networks, cellular communications, modems for broadband access, wireless networks, short-range communication, digital TV transmission, IP-TV or IP-telephony.
5 Prerequisites Computer Networks A 7.5 ECTS credits or similar Computer Engineering B, Wireless Internet access (most important!)Computer Engineering AB-level, 30 ECTS creditsTCP/IP networkingMathematical statisticsProgrammingOther helpful courses:Transform theory, 7.5 ECTS credits.Electrical engineering A, Analog electronics or Circuit theoryElectrical Engineering B, Telecommunications, 7.5 ECTS credits.Electrical engineering B, Signals and systems, 7.5 ECTS credits.Markov processes/Queueing theory
6 LitteratureMatlab, Simulink and Opnet documentation will be provided electronically.Please repeat physical layer issues and datalink layer issues in basic books in Computer Networks and Wireless Internet Access.
7 Requirements All lectures and supervision lessons are mandatory. You should attend 80% of the mandatory lessons.You are expected to devote 20 hours/week to this course.Quzzes (multiple choice tests): At least 70% correct answers.Lab: About 20 hours of work.Homework problem.Oral presentations.Project
8 Requirements on the project Review at least one research paper, and describe some standard and some existing simulation model.Simulate a communications standard, or check the simulations made in a research paper.At least modify an existing simulation model, for exampel a Simulink or Matlab demo, or build a model of your own (more difficult)Produce some plots for several parameter cases, showing for example BER, bit rate or delay as function of at least two different parameters, for example SNR, facing model, modulation scheme, etc.The simulation results should be stable (the plots smooth and not jerky), i.e simulate sufficiently long simulation time, or take the average of sufficiently large number of simulations.Draw some interesting conclusions from this.
9 Grading is based on Keeping deadlines. Quzzes. Showing good understanding when andwering questions from teachers and other students about your presentations.Extent of own code.Research relevance.Own new results or conclusions.
10 Time plan and deadlines (prel) Week 44-45 - Lectures repeating some theoryWeek 45 - Assignment 1 (homework problem).- Start lab: Intro to Simulink. (About 20 hours of work) - Electronic quizzes in webct - Choose a standard and en existing model to simulateWeek 46 Conclude lab (demonstrate to teachers)Week 47-48 - Present chapter 2 for class: Theory study – present astandard and review a research paper- Present chapter 3 for class: Model – present an existing simulation modelWeek 49-50 - Demonstrate chapter 1 to teachers: Introduction (goal of your project) - Demonstrate chapter 4: Modifications to an existing simulation model, or a new model that you have built.Week 51-02 - Demonstrate some simulation results to teachers.Week 03 - Final report and project presentations, incl chapter 5: Results, and chapter 6: Conclusions.
11 Assignment 1: Theory repetition The first assignment consists of old exam problems in Computer Networks A, Wireless Internet access B and Telecommunications B.Deadline: Friday course week 2. Be prepared to present your answers on the whiteboard.
12 Assignment 2: Simulink lab exercize Takes about hours to do.Deadline: Course week 3
13 Assignment 3: Present a standard and an existing simulation model Essentially chapter 2 (theory) and 3 (existing model that you start out from) of your report. Examples802.11b PHY Simulink model and adaptive modulation and link control256 channel ADSL and bit loading.Bluetooth Voice TransmissionBluetooth Full Duplex Voice and Data Transmission – Also describe Bluetooth low energy mode. Can be extended to thesis project.Digital Video Broadcasting Model (DVB-T). Also describe DVB-T2.NFC (Simulink model by previous years students – see Mathworks file archive).IEEE a WLAN Physical Layer. Also describe newer standards n, ac, ad or v positioning. Stefan, Erik, Andreas Gabriel.CDMA2000 Physical Layer.WCDMA Coding and Multiplexing.WCDMA Spreading and Modulation WCDMA End-to-end Physical Layer. Hassan, Lamin.Ultrawideband (UWB/wireless USB). See mathworks file archive. Fredrik, Markus, SebZigBee Simulink or Prowler model and IEEE g (smart grid). See mathworks file central. Altahra.ZigBee Prowler model and Multihop routing protocols (Prowler model) . You may demonstrate simulink model (see Matlab file central) or Prowler model. Perhaps you can add cooperative diversity. Yuxin Guo , Yu Tang, Suna Yin, Mengjun Qin.Opnet Mac Protocol MehrzadMobile WimaxLong-term evolution (LTE) Phy Downlink with spatial modeling. Also describe LTE-A. cheng yang, shixian wen, wei liuLong-term evolution (LTE) and eMBMSLine codes. Comparison of RZ, NRZ, AMI, Manchester coding (used in 10 Mbps Ethernet), 4B5B (used in 100Base-TX Ethernet) and PAM5 (used in 1000Base-T Gigabit Ethernet): For a code demonstrating RZ, NRZ, AMI and Manchester, see This code also requires this MATLAB function: During the rest of the project you may further develope the code to deal with 4B5B and PAM5, and to measure the bit error rate.Acoustic modem (new model)Acoustic QR code (continue on project by previous year’s students)
14 Assignment 3 (cont.)Oral presentation: Course week 3. Talk 5-10 minutes per person.Everyone should take notes, and everyone should ask questions and discuss the topic.Present:A standard (mention things like radio frequency, bandwidth, bit rate, modulation, error control method, multiplex method, multiple-access protocol, new/future versions)New versions of the standard or ongoing developmentScreen dumps – or demonstration of - an existing simulationDifferences between simulation and full standardFor higher grades:Also cite a related research paper or a textbook, for example a simulation method with results. See scholar.google.com or library.Within one week after that: Submit report chapter 2 (theory/previous research) and chapter 3 (existing model)
15 Assignment 4: Quizzes Basic concepts, Matlab and Simulink concepts Requirement: At least 70% correct answers.You can do them over and over again until the deadline.
16 Assignment 5: Opnet lab Zigbee and multihop simulation in Opnet. Takes about 4 hours to do.
17 Assignment 6: Present project suggestion Oral presentation course week 6.PresentProblem formulation (chapter 1) – what to parameters to evaluateCite simulation done in a research paper (if you have not done so)Planned own modification or development of model (chapter 4)Submit or show report chapters 1 and 4 before christmas.
18 Assignment 7: Final project presentation Demonstrate simulation code to teacher (and also in report appendice)Oral presentation in mid-January ofResults (chapter 5): Plot performance for several cases.Conclusions (chapter 6). Discuss similarities and differences from result in a cited research paper.Provide a preliminary report when you give your oral presentation.
19 F2. programmeringsteknik och Matlab MATLABMATLAB = Matrix Laboratory.Tool for numerical calculation and visualization. Commonly used for simulation of the communication system physical layer, signal and image processing research, etc.KTH, NADA, Vahid Mosavat
20 This is how MATLAB looks like F2. programmeringsteknik och MatlabThis is how MATLAB looks likeWorkspaceCommand historyCommand windowKTH, NADA, Vahid Mosavat
21 F2. programmeringsteknik och Matlab More MATLAB windowsFigure windowArray editorM-file editorKTH, NADA, Vahid Mosavat
22 How to get help in MATLAB? F2. programmeringsteknik och MatlabHow to get help in MATLAB?help functionsnameShows unformatted textdoc funktionsnamnShows HTML documentationin a browserKTH, NADA, Vahid Mosavat
23 SIMULINK SIMULINK: Toolbox in Matlab that allows graphical data-flow oriented programming.
24 Repetition of some basic concepts Frequency spectrumDigitalisation, source codingError codingModulationMultiple-access methodsBase-band modelDistorsion, noiseSignal-to-noise ratioBit-error ratioStatistics
27 PCM = Pulse Code Modulation = Digital transmission of analogue signals Number exemples from PSTN = the public telephone network1DA-converterAnti aliasing-filterSamplerInterpolationfilterAD-converter withseerial outputLoudspeakerMicrophone8 bit per sampeli.e bpsper phone call28 = 256 voltage levelsHzband pass filter. Stops everything over 4000Hz.8000sampelsper sec
36 8QAM example:Below you find eight symbols used for a so called 8QAM modem (QAM=Quadrature Amplitude Modulation). The symbols in the first row represent the messages 000, 001, 011 and 010 respectively (from left to right). The second row representents 100, 101, 111 and 110.
55 Filtering the Signal Types of filters Low pass Band pass High pass Filtering is equivalent to cutting all the frequiencies outside the band of the filterTypes of filtersLow passBand passHigh passLow passH(f)INPUTS1(f)OUTPUTS2(f)= H(f)*S1(f)H(f)fBand passH(f)INPUTS1(f)OUTPUTS2(f)= H(f)*S1(f)H(f)fHigh passH(f)INPUTS1(f)H(f)OUTPUTS2(f)= H(f)*S1(f)f
60 Multiple access = channel access Several transmitters sharing the same physical medium, for example wireless network, bus network or bus network.Based onA physical layer multiplexing schemeA data link layer MAC protocol (medium access control) that avoids collisions, etc.Examples:TDMA (time division multiple-access) based on TDMFDMA (frequency division multiple-access) based on FDMCDMA based on spread spectrum multiplexingCSMA (carrier sense multiple-access) based on packet switching = statistical multiplexingOFDMA
70 Orthogonal Frequency Division Multiplex (OFDM) Summary of advantagesCan easily adapt to severe channel conditions without complex equalizationRobust against narrow-band co-channel interferenceRobust against Intersymbol interference (ISI) and fading caused by multipath propagationHigh spectral efficiencyEfficient implementation using FFTLow sensitivity to time synchronization errorsTuned sub-channel receiver filters are not required (unlike conventional FDM)Facilitates Single Frequency Networks, i.e. transmitter macrodiversity.Summary of disadvantagesSensitive to Doppler shift.Sensitive to frequency synchronization problems.Inefficient transmitter power consumption, due to linear power amplifier requirement.
71 Bit error rate (BER) = Bit error probability = Pb Packet error rate (PER) = Packet error probability for packet length N bits:Pp = 1 – (1-Pb)N
72 Error-correcting codes (ECC), also known as Forward-error correcting codes (FCC) A block code converts a fixed length of K data bits to a fixed length N codeword, where N > K.A convolutions code inserts redundant bits into the bit-stream. Code rate ¾ means that for every 3 information bit, totally 4 are transferred, i.e. every forth of the transferred bits is redundant.
73 Bit rates Gross bit rate = Transmission rate. Symbol rate = Baud rate ≤ Gross bit rateIn spread spectrum: Chip rate ≥ Bit rate ≥ Symbol rate.In FEC: Net bit rate = Information rate = Useful bit rate ≤ Code rate * Gross bit rateMaximum throughput ≤ Net bit rateGoodput ≤ Throughput
74 Nyquist formulaGives the gross bit rate,without taking noise into consideration:Symbol rate < Bandwidth*2Bit rate < Bandwidth * 2log MThe above can be reached for line coding (base band transmission) and so called single-sideband modulation. Howeverm in practice most digital modulation methods give:Symbol rate = Bandwidth
75 Signal to noise ratiosS/N= SNR = Signal-to-noise ratio. Often same thing as C/N=CNR = Carrier-to-noise ratioSNR in dB = 10 log10 (S/N)S/I = SIR = Signal-to-interference ratio. Often the same thing as C/I=CIR = Carrier-to-interference ratio. I is the cross-talk power.CINR = C/(I+N) = Carrier-to-noise and interference ratioEb/N0 = Bit-energy (Power in watt divided by bitrate) divided by Noise density (in Watt per Hertz)Es/N0 = Symbol-energy (Power in Watt divided by bitrate) divided by Noise density (in Watt per Hertz)
76 Shannon-Heartly formula Gives the channel capacity, i.e. the maximum information rate (useful bit rate) excluding bit error rate.I=B log2 (1+C/N)Where C/N is carrier-to-noise ratio (sometimes called S/N)
79 Gaussian = Normal distribution Probability density funciton
80 Additive White Gaussian Noise (AWGN) channel White noise = wideband (unfiltered) noise with constant noise density in Watt/HertzPink noise = lowpass-filtered noise.Additive = linear mixing.SignalNoisy signal+Noise source
81 Bernoulli distribution Random sequence of independent 0:s and 1:s.
82 Exponential distribution Commonly used for time between phone calls and length of phonecalls. Simple model for calculation and simulation,but does not reflect data traffic bursty nature.
84 Rayleigh distribution Model of rayleigh fading, i.e. amplitude gain caused by multi-path propagation with no line-of-sight
85 More commons distributions Ricean distribution (fading with line-of-sight)Poisson distribution (number of phone calls during a phone call)Self-similar process (bursty data traffic)Rectangular distributionDiscrete distributions, for example the distribution of a dice