TECHNOLOGY FOCUS
We will discuss the modern digital modulation techniques and multiple access techniques of the physical (or radio) interface of all digital communication systems
Techniques such as OFDM, OFDMA, SOFDMA, SC-FDMA, DMT, MIMO, Massive MIMO, BLAST, CPM modulations (e.g., GMSK), and adaptive modulation and coding methods will be discussed. These techniques are used in broadband wireless communications, e.g., 5G-NR (based on 2n OFDM numerology), 4G-LTE and Wi-Fi 6 (IEEE802.11) and Wi-Fi 7. These methods are also in use in wireline systems such as ADSL and DOCSIS, as well as space and satellite communications. We will place special emphasis on the CP-OFDM modulation which is the standard for 5G-NR.
Recently there have been a number, of new modulation proposals, e.g., "Faster-Than-Nyquist" (FTN) signaling, index modulation and Orthogonal Time Frequency Space (OTFS) modulation. We will describe these concepts and techniques.
We will discuss Continuous Phase Modulations (CPM), e.g., GMSK used in Bluetooth and space communications. CPM modulation is also a possible candidate for 6G modulations.
We will also describe some of the important results of Shannon Information Theory, which are the basis for almost all communications.
COURSE CONTENT
We will describe the digital modulation techniques used in present major wireless and wireline communication systems and for those systems being planned, for the future. During the course we will discuss the latest versions of wireless systems including Fifth Generation (5G) cellular systems and the latest Wi-Fi systems. These systems use the latest modulation concepts and technologies. The 5G systems utilize many of the concepts to be discussed in the course. We will also discuss new ideas for 6G systems.
We begin the course with a discussion of the characteristics of major communications channels with special emphasis on the fading channel of wireless communications. We continue with a description of the classic modulations, e.g., Nyquist signaling, QPSK, QAM (and Offset QAM), CPM and GMSK, and the optimum receivers for these modulations. We will place special emphasis on OFDM and its related multiple access techniques, e.g., OFDMA, SOFDMA, SC-FDMA. This discussion will include a description of the radio interfaces of 5G-NR, 4G-LTE, and IEEE802.11 (Wi-Fi). We will also discuss some of the new OFDM-based proposals for 6G as well as other proposals for new modulations for future 6G systems, including "Faster-than-Nyquist" (FTN) signaling, and the OTFS (Orthogonal Time Frequency and Space) modulation.
We will cover the space, time and frequency diversity techniques used in new wireless systems with special emphasis on MIMO, BLAST and Massive MIMO techniques. Massive MIMO is one of the major elements of the standards for 5G-NR systems.
Other important subjects to be covered, are Alamouti space-time coding, iterative techniques, and adaptive modulation and coding. We will also discuss the very important limits on communications based on Shannon’s information theory. These limits are the basis for coding, OFDM, MIMO and other important results. Coding techniques including convolutional coding, turbo-coding, and LDPC codes will be described.
We will place special emphasis on constant envelope (CPM) modulations, e.g., GMSK and MSK, which are important modulations for wireless and space communications, and may find increased use in the future, e.g., 6G. And finally, we finish the course with a description of CDMA, a major multiple access technique, which was used in Second and Third Generation Cellular Systems.
After participating in this course, you will:
- Understand the modulations and multiple access techniques in use in modern mobile wireless (including satellite communications), broadband access and wireline communications, especially 4G-LTE, 5G-NR and Wi-Fi.
- Understand the OFDM, OFDMA, Scalable OFDMA (SOFDMA), SC-FDMA modulations and multiple access methods, as well as their implementation based on DMT
- Understand the performance of classic modulations such as QPSK and QAM, as well as the CPM modulations, e.g., GMSK
- Understand the space, time and frequency diversity techniques of wireless communications e.g., MIMO, Massive MIMO, BLAST, and Alamouti Coding
- Be familiar with the radio (or physical) interfaces of the 5G-NR, 4G-LTE and IEEE802.11 (Wi-Fi 6 and 7) systems
- Understand the challenges faced by the planners of the Sixth Generation (6G) systems and the possible solutions to these challenges
- Understand some old ideas like Offset QAM and "Faster-than-Nyquist" Signaling, which may be used in new 6G systems.
WHO SHOULD ATTEND
The course is aimed at engineers, scientists and algorithm developers who are interested in digital modulation and multiple access techniques for modern wireless and wireline communications.
The course should be of interest to those people who want to know about the OFDM (and OFDM-based modulations), MIMO and Massive MIMO techniques in use in 4G and 5G-NR.
The course should also be of interest to those who want to know more about constant envelope modulation techniques, e.g. GMSK.
Day 1
Rayleigh Fading Channel and Baseband Nyquist Signaling
The course begins with a description of the channel models for mobile wireless and wireline systems. This is followed by discussions of Nyquist baseband signaling, as well as ISI and linear equalization.
- "A Bit of History"
- Discussion of the Challenges Facing the Sixth Generation (6G)
- Introduction to Analog and Digital Communications
- System Model-The Channel
- The Multipath Channel (Rayleigh, Delay Spread and Frequency-Selective Fading)
- Introduction to Diversity Techniques-Antenna Diversity and Coding
- Twisted-Pair Channel
Brief Review of Fourier Transform, Power Spectral Density, White Noise
Nyquist Signaling
- ISI, Optimum Filtering, Square-Root Nyquist Filtering, Linear Equalization
- Partial Response Signals-Why the MLSE and the Viterbi Algorithm?
- What is "faster-than-Nyquist" Signaling?
Day 2
Signal Space, Optimum Detection
The concept of signal space is used to define the classical modulation techniques and derive the optimum detectors.
Signal Space, Optimum Detection
- Signal Space
- BPSK, QPSK, MPSK, QAM, BFSK and MFSK-Definitions
- Optimum Detection of Binary Signals and Probability of Error
- Matched Filter
The Rayleigh Fading Channel and Antenna Diversity-BLAST, MIMO
An in-depth discussion of the performance of modulations, transmitted over Rayleigh fading channels, followed by a discussion of the concept of space diversity (BLAST, MIMO and Massive MIMO), which is used to greatly improve spectral efficiency.
- Detectability Performance of BPSK over Rayleigh Fading Channel (SISO)
- Classic Antenna Diversity (SIMO)
- Space Diversity
- MIMO
- BLAST
- Massive MIMO-What is it? What can be gained?
Day 3
MSK-type Signals
QPSK, SQPSK, and MSK are essentially constant envelope modulations, which are used in many satellite and wireless systems.
- QPSK, SQPSK, pi/4 - QPSK, EDGE "8PSK", π/2-BPSK
- MSK-type (MSK, SFSK) Signals
- Adjacent Channel Interference (ACI)
M-ary Signals
M-ary signals are used in many systems, e.g., analog modems, ADSL, VDSL, microwave radio, and are the basic modulation of almost all OFDM systems.
- Optimum Detection of M-ary Signals
- MPSK
- Quadrature Amplitude Modulation (QAM)-Nyquist Signaling
- Offset QAM-OQAM- 6G Modulation Proposals
- MFSK
Shannon Information Theory
Shannon information theory is the basis behind much of what we do in communications including, coding, analog modems, ADSL, multitone modulation (DMT), OFDM, and adaptive modulation and coding. OFDM (DMT) is the modulation for 5G-NR, 4G-LTE, IEEE 802.11 (Wi-Fi 6 and 7), as well as ADSL and VDSL. We present an in-depth discussion of multitone modulation, DMT, OFDM, OFDMA, Scalable OFDMA and SC-FDMA. Then we will discuss the Radio Interfaces of 5G-NR, 4G-LTE and IEEE802.11., which are all based on OFDM.
Introduction to Shannon Information Theory
- Channel Capacity for Ideal and General Gaussian Channels
Multitone-DMT
- Discrete Multitone (DMT) - Implementation
- The Twisted Pair Channel
- Multitone (DMT) over the Twisted Pair Channel (ADSL and VDSL)
OFDM-Orthogonal Frequency Division Multiplexing
- OFDM - for Broadband Wireless Communications
- Adaptive Modulation and Coding Techniques
- OFDMA as a Multiple Access Technique
- Scalable OFDMA
- SC-FDMA (Single-Carrier FDMA-4G-LTE)
- OFDM-MIMO
Physical Interfaces of IEEE 802.11 (Wi-Fi 6 and 7), 4G-LTE and 5G-NR (including 2n numerology)
- Wi—Fi 6 and 7
- 3G-LTE, 4G-LTE,5G-NR
- 6G (?)
Day 4
Trellis Coding, Convolutional Coding and The Viterbi Algorithm
We continue with a description of trellis coded modulation concepts and convolutional coding, including a discussion of the Viterbi Algorithm. We also include the topic of interleaving for improving the performance of modulations on Rayleigh fading channels.
- The Viterbi Algorithm (VA)
- Ungerboeck Trellis Coding
- The VA Equalizer
- Interleaving for Rayleigh Fading
- Performance on the Rayleigh Fading Channel
- Convolutional Coding
"Faster-Than-Nyquist (FTN) Signaling" and Other Modulation Proposals for 6G
- What is FTN?
- What is its performance?
- Index Modulation and OTFS
Turbo-Coding-Introduction
A topic of increasing importance is the turbo-coding (iterative decoding) concept and its use in areas such as antenna diversity, equalization and OFDM.
- Turbo Coding
- Iterative Decoding Techniques
- Turbo-Equalization
- Introduction to LDPC Codes
Capacity of Rayleigh Fading Channels
Shannon's work has been updated to include bounds on the performance of Rayleigh fading channels. This work led to the concept of MIMO and space-time (Alamouti) coding.
- Bounds on Communications for Fading Channels
- OFDM-MIMO-Coding
- Space-Time Coding
- Alamouti Coding
- Multi-User Diversity Techniques
Day 5
Continuous Phase Modulations (CPM)
CPM signals (e.g., GMSK) are constant envelope, bandwidth efficient modulations, suitable for use with nonlinear power efficient, transmitting power amplifiers. These modulations are used in GSM and deep space communications, as well as Bluetooth.
- Continuous Phase Modulation (CPM)
- Gaussian MSK (GMSK)
- Tamed FM (TFM)
- Generalized TFM (GTFM)
- Constant Envelope OFDM
- Adjacent Channel Crosstalk in CPM Signals
Non-Coherent Detection
- DPSK
- FM Detection of CPM Signals-Bluetooth, DECT
CDMA and WCDMA
We continue with a discussion of CDMA and WCDMA, and describe the radio interfaces of the IMT-2000 WCDMA system, as well as the physical interface of IS-95.
- The RAKE Receiver
- Pseudo-Random Sequences
- Power Control
- Intra and Inter-Cell Interference and Capacity
- IS-95 Physical Interface
- IMT-2000 WCDMA Physical Interface: Walsh and OVSF Functions
Summary and the Future
Said about hte course from previous participants:
"Practical examples and exercises."
"A lot of interaction, good depth in material. Practical measurements on hardware."
"Clear slides and booklet. Clear explanations."
"The level of the course has been chosen properly matched with the audience level."
"Instructor with plenty of real-life practical knowledge."