Prerequisites & Notation
Before You Begin
The preceding 18 chapters developed OTFS as a mathematical framework and as a family of algorithms. This chapter steps back to the ecosystem question: how does OTFS enter the 6G standards process? What does it compete with? What does the migration from 5G NR look like? The answers blend technical assessment with the realities of 3GPP politics — OTFS is not adopted because it is theoretically superior, but because it solves specific problems that the incumbent waveform (OFDM in its DFT-spread form) cannot.
- OTFS modulation and detection(Review OTFS Ch. 6, 8)
Self-check: Can you write the OTFS transmitter chain (ISFFT + Heisenberg) and name the dominant detector?
- Performance under mobility(Review OTFS Ch. 9-10)
Self-check: Do you recall the OTFS vs OFDM BER scaling under integer/fractional Doppler?
- Cell-free and LEO extensions(Review OTFS Ch. 17-18)
Self-check: Can you state the 35% cell-free gain and the OFDM breakdown at LEO?
- 5G NR air interface(Review Telecom Ch. 24)
Self-check: Do you know the basics of OFDM/CP-OFDM, DFT-s-OFDM, and 5G NR numerology?
- Multiple access(Review Telecom Ch. 19, ITA Ch. 14)
Self-check: Are you comfortable with OFDMA, NOMA, and the broadcast channel?
Notation for This Chapter
6G-standardization-specific symbols introduced here.
| Symbol | Meaning | Introduced |
|---|---|---|
| Subcarrier spacing (5G NR: 15-480 kHz) | s01 | |
| 5G NR numerology index (0-5, kHz) | s02 | |
| 5G NR slot size (14 OFDM symbols) | s02 | |
| DFT precoding matrix (DFT-s-OFDM) | s02 | |
| Access domain set: {time, freq, code, spatial, DD} | s03 | |
| Multi-domain access aggregate rate | s03 |