Prerequisites & Notation

Before You Begin

This chapter brings together the OTFS machinery (Chapters 4-10) and the radar framework (Chapter 11) into a single design question: how do we jointly sense the environment and transmit data with one waveform? The answer is OTFS-ISAC, the centerpiece of the CommIT group's 2020-2024 contributions to integrated sensing and communication.

OTFS modulation and DD input-output(Review OTFS Ch. 6, Ch. 4)
Self-check: Can you state the DD input-output relation and connect it to the transceiver chain?
OTFS detection (MP, LCD, IDD)(Review OTFS Ch. 8)
Self-check: Do you know how MP-OTFS processes the DD factor graph?
Ambiguity function and radar resolution(Review OTFS Ch. 11)
Self-check: Can you state the thumbtack-ambiguity claim and the range/velocity resolutions?
Fractional Doppler and BEM(Review OTFS Ch. 10)
Self-check: Do you recall that fractional-offset estimation is central to fine-velocity sensing?
Classical ISAC theory(Review Telecom Ch. 29)
Self-check: Are you familiar with the ISAC rate-distortion framework?

Notation for This Chapter

Symbols introduced in this chapter.

Symbol	Meaning	Introduced
$R_{\text{comm}}, D_{\text{sens}}$	Communication rate (bits/s) and sensing distortion (CRLB-type)	s01
$\mathcal{P}$	Pareto frontier in the rate-distortion plane	s04
$\mathcal{T}$	Target scene: $\mathcal{T} = \{(\tau_i, \nu_i, a_i)\}_{i=1}^{P}$	s01
$\Theta$	Target parameter vector: $\Theta = (\tau_1, \nu_1, \tau_2, \nu_2, \ldots)$	s03
$J(\Theta)$	Fisher information matrix for target parameter estimation	s03
$\eta_{\text{sense}}$	Sensing fraction of transmit power (or time)	s04

← Ch 11 The ISAC Problem