A survey of 5G millimeter wave, massive multiple-input multiple-output, and vehicle-to-vehicle channel measurements and models

Abstract

There is no doubt that the world evolves nowadays in the digital communications era. This opens the horizon to research and investment in new promising technologies like 5G and beyond cellular networks that are able to increase the subscribers' data rates in all communication systems. The aim of 5G and beyond cellular networks is to provide anywhere and anytime connectivity. By combining the enormous available bandwidth in millimeter wave (mmWave) frequencies with high multiplexing gains achieved by large antenna arrays in multiple-input multiple-output (MIMO) systems, these technologies can significantly improve network throughput, increase network power, boost energy and spectral efficiency, and enhance network coverage. Furthermore, ultra-reliable vehicular communication and high capacity would be essential features of communication networks beyond 5G. Fortunately, when vehicles are moving on the road and communicating with each other, the vehicular communication issue becomes more challenging. Among the several new technologies expected to play significant roles in the 5G and beyond systems, this paper focused on summarizing the state-of-the-art mmWave, vehicle-to-vehicle (V2V), and massive MIMO measurements and models. We introduce a detailed overview of each of the three technologies individually. Besides, novel taxonomies for the 5G channel measurements, objectives, and model types are provided. We expect that mmWave-based massive MIMO technology enables real-time channel estimation and ultra-precise beamforming, and thus enables better service coverage. Finally, challenges and future research directions for 5G channel measurements and models are presented.