Intelligent reflecting surfaces, cell-free massive MIMO, and smart radio networks.

If you are a student or researcher, you can often download individual chapters or the full text for free through your institution's subscription on the IEEE Xplore platform.

This guide is a primary resource for 6G development, covering:

Terahertz (THz) communications, visible-light, and enhanced millimeter wave.

The publisher provides the full eBook for purchase or institutional access.

Based on your search for "Key Technologies Comprehensive Guide," you are likely looking for the 2022 Wiley-IEEE Press book by Wei Jiang and Fa-Long Luo.