Digital Communications

Introduction

• Organization of the Course
• Additional Course Resources

Signals and Spectra

• Digital Communication Signal Processing
• Classification of Signals
• Spectral Density
• Autocorrelation
• Random Signals
• Signal Transmission Through Linear Systems
• Bandwidth of Digital Data
• Conclusion
• References
• Problems
• Questions

Formatting and Baseband Modulation

• Baseband Systems
• Formatting Textual Data (Character Coding)
• Messages, Characters, and Symbols
• Formatting Analog Information
• Sources of Corruption
• Pulse Code Modulation
• Uniform and Nonuniform Quantization
• Baseband Transmission
• Correlative Coding
• Conclusion
• References
• Problems
• Questions

Baseband Demodulation/Detection

• Signals and Noise
• Detection of Binary Signals in Gaussian Noise
• Intersymbol Interference
• Equalization
• Conclusion
• References
• Problems
• Questions

Bandpass Modulation and Demodulation/Detection

• Why Modulate?
• Digital Bandpass Modulation Techniques
• Detection of Signals in Gaussian Noise
• Coherent Detection
• Noncoherent Detection
• Complex Envelope
• Error Performance for Binary Systems
• M-ary Signaling and Performance
• Symbol Error Performance for M-ary Systems (M > 2)
• Conclusion
• References
• Problems
• Questions

Communications Link Analysis

• What the System Link Budget Tells the System Engineer
• The Channel
• Received Signal Power and Noise Power
• Link Budget Analysis
• Noise Figure, Noise Temperature, and System Temperature
• Sample Link Analysis
• Satellite Repeaters
• System Trade-Offs
• Conclusion
• References
• Problems
• Questions

Channel Coding: Waveform Codes and Block Codes

• Waveform Coding and Structured Sequences
• Types of Error Control
• Structured Sequences
• Linear Block Codes
• Error-Detecting and Error-Correcting Capability
• Usefulness of the Standard Array
• Cyclic Codes
• Well-Known Block Codes
• Conclusion
• References
• Problems
• Questions

Channel Coding: Convolutional Codes and Reed–Solomon Codes

• Convolutional Encoding
• Convolutional Encoder Representation
• Formulation of the Convolutional Decoding Problem
• Properties of Convolutional Codes
• Other Convolutional Decoding Algorithms
• Reed–Solomon Codes
• Interleaving and Concatenated Codes
• Coding and Interleaving Applied to the Compact Disc Digital Audio System
• Conclusion
• References
• Problems
• Questions

Channel Coding: Turbo Codes and Low-Density Parity Check (LDPC) Codes

• Turbo Codes
• Low-Density Parity Check (LDPC) Codes
• Appendix 8A: The Sum of Log-Likelihood Ratios
• Appendix 8B: Using Bayes’ Theorem to Simplify the Bit Conditional Probability
• Appendix 8C: Probability that a Binary Sequence Contains an Even Number of Ones
• Appendix 8D: Simplified Expression for the Hyper...e Natural Log of a Ratio of Binary Probabilities
• Appendix 8E: Proof that 𝛟(x) = 𝛟–1(x)
• Appendix 8F: Bit Probability Initialization
• References
• Problems
• Questions

Modulation and Coding Trade-Offs

• Goals of the Communication System Designer
• Error-Probability Plane
• Nyquist Minimum Bandwidth
• Shannon–Hartley Capacity Theorem
• Bandwidth-Efficiency Plane
• Modulation and Coding Trade-Offs
• Defining, Designing, and Evaluating Digital Communication Systems
• Bandwidth-Efficient Modulation
• Trellis-Coded Modulation
• Conclusion
• References
• Problems
• Questions

Synchronization

• Receiver Synchronization
• Synchronous Demodulation
• Loop Filters, Control Circuits, and Acquisition
• Phase-Locked Loop Timing Recovery
• Frequency Recovery Using a Frequency-Locked Loop (FLL)
• Effects of Phase and Frequency Offsets
• Conclusion
• References
• Problems
• Questions

Multiplexing and Multiple Access

• Allocation of the Communications Resource
• Multiple-Access Communications System and Architecture
• Access Algorithms
• Multiple-Access Techniques Employed with INTELSAT
• Multiple-Access Techniques for Local Area Networks
• Conclusion
• References
• Problems
• Questions

Spread-Spectrum Techniques

• Spread-Spectrum Overview
• Pseudonoise Sequences
• Direct-Sequence Spread-Spectrum Systems
• Frequency-Hopping Systems
• Synchronization
• Jamming Considerations
• Commercial Applications
• Cellular Systems
• Conclusion
• References
• Problems
• Questions

Source Coding

• Sources
• Amplitude Quantizing
• Pulse Code Modulation
• Adaptive Prediction
• Block Coding
• Transform Coding
• Source Coding for Digital Data
• Examples of Source Coding
• Conclusion
• References
• Problems
• Questions

Fading Channels

• The Challenge of Communicating over Fading Channels
• Characterizing Mobile-Radio Propagation
• Signal Time Spreading
• Time Variance of the Channel Caused by Motion
• Mitigating the Degradation Effects of Fading
• Summary of the Key Parameters Characterizing Fading Channels
• Applications: Mitigating the Effects of Frequency-Selective Fading
• Conclusion
• References
• Problems
• Questions

The ABCs of OFDM (Orthogonal Frequency-Division Multiplexing)

• What Is OFDM?
• Why OFDM?
• Getting Started with OFDM
• Our Wish List (Preference for Flat Fading and Slow Fading)
• Conventional Multi-Channel FDM versus Multi-Channel OFDM
• The History of the Cyclic Prefix (CP)
• OFDM System Block Diagram
• Zooming in on the IDFT
• An Example of OFDM Waveform Synthesis
• Summarizing OFDM Waveform Synthesis
• Data Constellation Points Distributed over the Subcarrier Indexes
• Hermitian Symmetry
• How Many Subcarriers Are Needed?
• The Importance of the Cyclic Prefix (CP) in OFDM
• An Early OFDM Application: Wi-Fi Standard 802.11a
• Cyclic Prefix (CP) and Tone Spacing
• Long-Term Evolution (LTE) Use of OFDM
• Drawbacks of OFDM
• Single-Carrier OFDM (SC-OFDM) for Improved PAPR Over Standard OFDM
• Conclusion
• References
• Problems
• Questions

The Magic of MIMO (Multiple Input/Multiple Output)

• What is MIMO?
• Various Benefits of Multiple Antennas
• Spatial Multiplexing
• Capacity Performance
• Transmitter Channel-State Information (CSI)
• Space-Time Coding
• MIMO Trade-Offs
• Multi-User MIMO (MU-MIMO)
• Conclusion
• References
• Problems
• Questions

Encryption and Decryption

• Models, Goals, and Early Cipher Systems
• The Secrecy of a Cipher System
• Practical Security
• Stream Encryption
• Public Key Cryptosystems
• Pretty Good Privacy
• Conclusion
• References
• Problems
• Questions

Appendix A: A Review of Fourier Techniques

• Signals, Spectra, and Linear Systems
• Fourier Techniques for Linear System Analysis
• Fourier Transform Properties
• Useful Functions
• Convolution
• Tables of Fourier Transforms and Operations
• sampled data fourier transform

Appendix B: Fundamentals of Statistical Decision Theory

• Bayes’ Theorem
• Decision Theory
• Signal Detection Example

Appendix C: Response of Correlators to White Noise

Appendix D: Often-Used Identities

Appendix E: s-Domain, z-Domain, and Digital Filtering

• The Laplace Transform
• The z-transform
• Digital Filtering
• Finite Impulse Response Filter Design
• Infinite Impulse Response Filter Design

Appendix F: OFDM Symbol Formation with an N-Point Inverse Discrete Fourier Transform (IDFT)

Appendix G: List of Symbols