This lesson covers the waveform in 4G and its primary component, Orthogonal Frequency Division Multiplexing (OFDM). The lesson delves into the details of OFDM, its advantages, and its role as the foundation for modern communication techniques. It also discusses the application of OFDM in various systems like 4G, 5G, broadband wireless local area networks, and digital audio broadcasting. The lesson further explains the concept of spectral efficiency and how OFDM contributes to it. For instance, it uses the example of a 64 QAM signal space diagram to illustrate how OFDM works.
00:18 - Introduction
04:03 - OFDM in 4G systems
05:26 - Brief history of OFDM
18:57 - Fundamental elements: QAM
21:14 - OFDM and its advantages in terms of spectral efficiency
22:26 - Orthogonality criteria in OFDM and its role in reducing adjacent channel interference
24:00 - Explanation of the use of 64 QAM in OFDM and the concept of gray coding to reduce error probability
- Orthogonal Frequency Division Multiplexing (OFDM) is the primary waveform in 4G and serves as the foundation for most modern communication techniques.
- OFDM is a multi-carrier technique that allows for high spectral efficiency and is used in various communication systems, including 4G, 5G, broadband wireless local area networks, and high-speed satellite communications.
- The orthogonality criteria in OFDM allow for overlapping sub-carriers without interference, leading to significant bandwidth savings.
- OFDM has been implemented in digital circuits, making it more power-efficient and cost-effective.
- The application of OFDM in fourth-generation communication systems has led to higher spectral efficiency.