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Exercise Session: Simulate and Practice

Exercise Session: Simulate and Practice

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Exercise Session: Simulate and Practice

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  1. Exercise Session:Simulate and Practice Wireless Access Systems

  2. Communication Technology Laboratory Wireless Communication Group Introduction: Simulate, practice and verify We will simulate the theoretical schemes/methods/techniques that we learn throughout the lecture. In general we will simulate Single carrier transmission Multi-carrier transmission Wireless channel Channel coding Simple UWB transceiver MATLAB (matrix laboratory) will be used for simulations.

  3. Communication Technology Laboratory Wireless Communication Group Organization: Exercise x Group 1,3&5 Task 1 Exercise x Group 2,4&6 Task 2 2 weeks Exercise x Combination Task Groups {1,2},{3,4}&{5,6} 1 week • The groups present their work during the exercise session • Presentation • Corrections will have to be made if necessary Group-1/2 Group-3/4 Group-5/6 Discussions Exercise-x, Task-y 10 min 10 min 15 min 10 min

  4. Communication Technology Laboratory Wireless Communication Group Let’s split into groups:

  5. Communication Technology Laboratory Wireless Communication Group Schedule:

  6. Communication Technology Laboratory Wireless Communication Group Organization Details (1) Follow the instructions, simulate and plot/present the results. Unless explicitly informed, do not use MATLAB built-in functions Follow the plan describing how the tasks are split amongst the groups. Note that understanding both task is relevant for the final exam. Deliverable is due one day prior to the presentation – 17h00 Deliverable includes: presentation (PDF or Power Point file) with filename: Group_No_Exercise_No_Task_No_Date a folder contaning all MATLAB files that you use, again with name: Group_No_Exercise_No_Task_No_Date

  7. Communication Technology Laboratory Wireless Communication Group Organization Details (2): The groups must email their work to zemenem@nari.ee.ethz.ch before the deadline! All documents will be placed on our course website, too. There you find also templates for the presentations. All documents regarding the lecture are placed on the lecture website in a restricted area ( Lecture Notes) with: Username: was Password: wireless The simulate and practice track is a core/central element of the course

  8. Communication Technology Laboratory Wireless Communication Group Exercise Grading • Every exercise will be graded with a maximum 30 points • Task 1/2: 20 points • Combination task: 10 points • Maximum collected points from 3 exercises: 90 points • Minimum points to pass the simulate and practice track: 45 points • Bonus grade from the exercise • We verify the participation of all group members • It is possible to receive the maximum grade without the bonus from the exercises

  9. Communication Technology Laboratory Wireless Communication Group Contact Information: Responsible persons for Simulate & Practice Track: and Zemene Walle Mekonnen Room: ETF F 108 Email: zemenem@nari.ee.ethz.ch Yehia Hassan Room: ETF F 104 Email: yehassan@nari.ee.ethz.ch Prof. Dr. Armin Wittneben Room: ETF F 109 Email: wittneben@nari.ee.ethz.ch

  10. Communication Technology Laboratory Wireless Communication Group Exercises in detail: • Exercise 1: Single carrier modulation: PSK/QAM • Task 1: Continuous time simulations • Task 2: T-spaced (discrete) time simulations • Combine and present a complete continuous time symbol modulator • Exercise 2: OFDM • Task 1: Channel coding • Task 2: OFDM • Combine and present a complete OFDM modem • Exercise 3: UWB transceiver • Task 1: UWB Tx • Task 2: UWB Rx • Combine and present a complete UWB transceiver

  11. Communication Technology Laboratory Wireless Communication Group Wireless Access Systems:Exercise 1 – Single Carrier PSK/QAM

  12. Communication Technology Laboratory Wireless Communication Group Exercise 1 – Single Carrier PSK/QAM • We will simulate basic modulation schemes: BPSK/QPSK/16-64 QAM • Next two weeks: • Task 1: Group 1, Group 3 and Group 5 • Implement a continuous time BPSK modulator/demodulator in AWGN • Extend it to multipath channel. • Task 2: Group 2, Group 4 and Group 6 • Implement a symbol time spaced BPSK/QPSK/16-64 QAM mapper/demapper. • 3rd week: • Combination Task: Groups {1,2}, Groups {3,4} and Groups {5,6}: • Investigate pulse shapes • Continuous time QPSK modulator/demodulator in multipath channel.

  13. Communication Technology Laboratory Wireless Communication Group Task 1 - Introduction • For PSK, the information is encoded in the phase of the transmit signal. • BPSK:

  14. Communication Technology Laboratory Wireless Communication Group Task 1 – BPSK modem in AWGN • Generate the noise • Based on the required Signal to Noise Ratio (SNR) • Comparison with theoretical BER results.

  15. Communication Technology Laboratory Wireless Communication Group Task 1 – BPSK in multipath channel • Channel: We model the multi-path channel with a finite impulse response filter 0.8 0.6

  16. Communication Technology Laboratory Wireless Communication Group Task 2 - Introduction • The signal space diagrams of BPSK, QPSK, 16-QAM and 64-QAM constellations are

  17. Communication Technology Laboratory Wireless Communication Group Task 2 – Constellation points for QAM • Design constellation points for QAM • Gray mapping and average symbol energy is E.

  18. Communication Technology Laboratory Wireless Communication Group Task 2 – Gray Codes (Reflected Binary Codes) • Adjacent constellation points differ by only one bit, e.g.: • Minimization of bit error (single bit error for adjacent symbol) • Iterative construction, e.g.: • Reflect: {0,1}  {1,0} • Append prefix: {00, 01}, {11, 10} • Concatenate: {00, 01, 11, 10}

  19. Communication Technology Laboratory Wireless Communication Group Task 2 – Mapper/Demapper • Write two MATLAB functions called mapper and demapper. • Mapper: • Maps the bit sequence to BPSK/QPSK/16-64 QAM symbols. • Inputs: • A bit sequence • The constellation type • Output: • Corresponding symbol sequence • Demapper: • Maps the BPSK/QPSK/16-64 QAM symbol sequence to bits. • Inputs: • A symbol sequence • The constellation type • Output: • A bit sequence

  20. Communication Technology Laboratory Wireless Communication Group Task 2 – Bit/Symbol Error Rates • Simulate BER/SER of the different constellation types in AWGN. • Noisy symbol vector • Plot BER/SER vs SNR. • Compare simulation results with theoretical results.

  21. Communication Technology Laboratory Wireless Communication Group Combination Task – Pulse Shapes • The spectral efficiency of a rectangular pulse is very poor. • Pulse shaping reduces the energy wasted in the side-lobes • The pulses must satisfy the Nyquist criterion to avoid ISI. • The raised cosine function is one of the commonly used pulse shapes. • The roll-off factor β is a measure of the excess bandwidth.

  22. Communication Technology Laboratory Wireless Communication Group Combination Task – QPSK

  23. Communication Technology Laboratory Wireless Communication Group Combination Task – QPSK • QPSK modulator is nothing but a two-branch BPSK modulator. • Split into: • In-phase component • Quadrature component