uch as RF signal-based simultaneous wireless information and power transfer (SWIPT) provides a viable solution by enabling the energy constraint nodes to scavenge the energy. The EH implementation protocols have been discussed in this chapter before introducing the device-to-device (D2D) multiple-input and multiple-output (MIMO) relays along with SWIPT. This chapter also examines the practical constraints such as feedback errors, imperfect channel state information over the system performance, and the useful insights in system design considering the impacts of channel conditions, multiple antennas, and energy harvesting parameters. The chapter "Vehicular Communications in the B5G Era" presents the require- ments and challenges in the design and analysis of advanced wireless communica- tion systems for vehicular communications (from V2V to V2X). Different types of vehicular network configurations, in terms of antenna subsystems and transceivers, have been described in relation with the impact of dense urban, urban, and rural scenarios in system implementation. Examples of coverage/capacity relations for vehicular communication scenarios have also been presented based on volumetric geometric/stochastic modelling techniques. The chapter "Implementation of Context-Aware Environments with Massive IoT Systems" describes the framework for IoT evolution, from current LPWAN/5G connectivity to future B5G systems, taking advantage of sub THz (mainly in the 100-300 GHz frequency range) and THz bands (up to 10 THz). The current needs and future evolution of IoT applications require device integration, node density, interference, and energy handling. Coverage/capacity estimations for different case uses within dense urban/urban/sub-urban settings are being presented based on deterministic volumetric wireless channel estimation. Different application scenar- ios, such as the evolution of current IoT applications towards sensing networks, are also discussed based on the description of three realistic use case scenarios. The chap