Chapter 3: RIS Channel Models

Learning Objectives

• Build the cascaded channel $\mathbf{H}_{\text{eff}} = \mathbf{H}_2 \boldsymbol{\Phi} \mathbf{H}_1$ for the multi-antenna UE case and explain every dimension
• Distinguish near-field and far-field regimes for a large RIS aperture
• Write the LoS BS–RIS channel using array steering vectors and identify the rank of $\mathbf{H}_1$
• State the spatial-correlation model for RIS channels under rich scattering
• Use the product path-loss law as a system-level input to deployment planning