How To Learn Wi-Fi
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Learning Wi-Fi can be quite complicated for beginners. Start with legacy Wi-Fi, i.e., 20 MHz OFDM with SISO, which is sufficient to understand the important Wi-Fi design.
0. OFDM
- Read Chapter 2 of Book: Next Generation Wireless LANs 802.11n and 802.11ac
1. Understand Wi-Fi Physical Layer
Transmitter
- Read Chapter 4 of Book: Next Generation Wireless LANs 802.11n and 802.11ac (Focus on Section 4.1 in the beginning). Understand the preamble design (short training symbols and long training symbols).
Channel
- Read Chapters 1-3 of MIMO-OFDM Wireless Communications with MATLAB. Understand what is multipath channel. Focus on small-scale fading in the beginning.
- Matlab has modeled the fading channels, which can be found here
- Propagation Channel Models for WiFi/IEEE 802.11
Receiver
Check this paper Performance Assessment of IEEE 802.11p with an Open Source SDR-Based Prototype for the receiver design, including time synchronization, frequency offest estimation, channel estimation, etc.
The following algorithm should be carefully studied:
- Packet detection: How to use short training symbol for coarse time synchronization
- Symbol alignment: How to use long training symbol for fine time synchronization
- Carrier frequency offset estimation and correction
- Channel estimation
2. Matlab Simulation
- Run 802.11n Packet Error Rate Simulation for 2x2 TGn Channel to understand physical layer algorithms. Setting the number of transmit antennas to 1 in the example.
- Model 802.11a/b/g/j/p-related signal reception functionality: Understand each receiver algorithm
3. Experimental Practice
- Software-defined radio (SDR): if you have SDR platforms (USRP or PlutoSDR), check Matlab WLAN SDR examples
- ESP32: try ESP32 CSI Toolkit to get CSI
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