ECE 463

• Communications

• Introduction
• TX/RX Transceivers
• Modulation
• Synchronization
• Communication Channel
• Orthogonal Frequency Division Multiplexing (OFDM)
• IoT Technologies

• Introduction
  • Components of Digital Communication System
  • Spectrum Analyzer tutorial, power spectral-density measurements
  • Software Defined Radios
  • USRP X310
  • LabView Communications
• TX/RX Transceivers
  • Up and Downconversion
  • Pulse Shaping Filters and Matched Filters
  • Bandwidth and Spectral Efficiency
  • Eye Diagrams
  • Automatic Gain Control
  • Quantization
• Modulation
  • Coherent Modulation
  • Non-Coherent Modulation
  • DPSK, ASK, FSK, CFSK, PSK, QAM,
  • Maximum Likelihood decoder
  • Bit error rate (BER) vs Eb/No and SNR
• Synchronization:
  • Frame Synchronization and PN Sequences
  • Timing Recovery
  • Carrier Frequency offset estimation & correction.
  • Phase Tracking
  • Phase Lock Loops (PLLs)
• Channel
  • AWGN Channel
  • Flat Fading vs Frequency Selective Channel
  • Inter-Symbol-Interference
  • Channel Equalization
  • Channel Capacity​
• Orthogonal Frequency Division Multiplexing (OFDM)
  • ​DFTs and IDFT
  • Packet Detection
  • Cyclic Prefix, FFT Window & ISI
  • Channel Estimation and Correction
  • CFO Estimation and Correction
  • Pilots and CFO & SFO Tracking.
• IoT Technologies
  • Bluetooth & Frequency Hoping
  • LoRa & Chirp Spread Spectrum
  • RFIDs & Battery Free Communication
  • Direct Sequence Spread Spectrum

Class notes.

The goals are to familiarize students with the techniques and instrumentation employed for measuring the performance and properties of digital communication systems and to provide hands-on experience with the components and sub-systems employed in a digital communication system.

After Laboratory Exercise No. 4, the students should be able to do the following:

• Learn to use software-defined radios to transmit and receive digital communication signals. (1,6)
• Understand the different components of a digital communication system: LNA, PA, ADC, DAC, Pulse shaping filter, Matched filter, Modulation, Demodulation, AGC, LPF, BPF. (1)
• Design a test procedure and measure the bit energy and noise power spectral density in analog signals of a baseband communication system using both time-domain and frequency-domain measurement techniques. (1,2,5,6)
• Analyze the performance of a baseband communication system that employs ideal Nyquist-based pulse shaping and matched filter responses in the presence of symbol-timing (clock) synchronization error. (1,5,6)
• Analyze the performance of a practical implementation of a detector that employs non-Nyquist-based pulse shaping and/or non-matched filtering by accounting for inter-symbol-interference and timing errors. (1,5,6)
• Understand the principles of operation for a symbol-timing recovery loop. (1)
• Apply their understanding of non-coherent modulation to recover the channel bits of a DPSK signal. (1,5,6)

After Laboratory Exercise No. 8, the students should be able to perform all of the items listed under A plus the following:

• Apply their understanding of the carrier-recovery system to recover the channel bits of an over-the-air binary-FSK and ASK pager signals. (1,5,6)
• Understand the principles and practicality of implementing a self-synchronizing bit error detector for testing arbitrary digital communication systems. (1)
• Design a procedure to generate the noise variance required per sample to achieve a desired Eb/No in digital signals. (1,2,5,6)
• Design a procedure to estimate and correct the signal distortion created by the channel and hardware including channel equalization and CFO correction. (1,2,5,6)
• Design a test procedure and measure the bit-error probability in a baseband communication system as a function of Eb/No. (1,2,5,6)
• Design a test procedure and measure the bit-error performance in a BPSK, QAM, and QPSK communication system as a function of symbol-timing (clock) error, Eb/No and carrier-phase error. (1,2,5,6)
• Understand the operation of a Costas-loop for carrier phase synchronization in a communication system. (1)

After the final Laboratory Exercise, the students should be able to perform all of the tasks listed under A and B plus the following:

• Understand the operation of an OFDM based digital communication system. (1)
• Implement and over-the-air OFDM baseband communication system that corrects for channel impulse response and inter-symbol-interference and analyze its performance in the absence of synchronization error. (1,5,6)
• Design and analyze the most common digital modulation schemes on the basis of spectral efficiency, power efficiency, and practical implementation. (1,2,5,6)
• Understand the design of various digital communication technologies underlying low power IoT systems. (1)
• Implement and over-the-air Chirp Spread Spectrum digital communication system that corrects for carrier and timing synchronization errors and correctly transmits and decodes digital bits. (1,5,6)
• Design, test, and construct a receiver for the digital transmission of an over-the-air (OTA) signal of their choosing, subdivide the project into tasks among themselves, construct and test the coded LabVIEW “subVIs,” and collectively report their working solution. Likely OTA signals include the Radio Broadcast Data System (RBDS) digital subcarrier of a local FM radio broadcast, digital radio, or unencrypted digital television. (1,2,3,5,6,7)