Let us trace a single Wi-Fi 6 frame from your laptop's IP layer down to RF and back, stitching together everything we have built.
The principles you have just read appear here line by line: PCM-style ADC at the front, source coding above the MAC, channel coding via LDPC, QAM modulation, OFDM (a vast parallel array of QAM tones), pulse shaping with SRRC, carrier and timing recovery, equalization in the frequency domain, soft demodulation, and CRC-32 for residual error detection. Every Wi-Fi 6 link in your home is a working laboratory of this entire chapter.
LTE and 5G NR are nearly identical in structure. So is DOCSIS. So, with different coding choices, is DVB-S2 satellite TV. Once you have learned this stack, you have learned the physical layer of essentially the entire wireless world.