Survey, Taxonomy, and Unification of Standard mmWave Channel Models for WPAN, WLAN, and Cellular Systems in 6G

This study aims to provide a unified view of the various standard millimeter-wave (mmWave) channel modeling frameworks for mmWave wireless deployments in sixth generation (6G) wireless networks, focusing on wireless personal area networks (WPAN), wireless local area networks (WLAN), and cellular networks (CN). The 6G era will witness the emergence of security-sensitive, more mission-critical, and data-intensive applications, wherein massive amount of data will be exchanged while satisfying the stringent requirements for latency, reliability, trustworthiness, and data rate. Thus, mmWave connectivity has been considered and would result in the co-existence of decentralized networks and centralized CNs, eventually blurring the distinction between WPANs, WLANs, and CNs. Motivated by this futuristic vision, we first reviewed the present status of the standard channel models for WPAN, WLAN, and CNs to understand the common characteristics of mmWave channel models therein. We show that despite their differences in sight-specificity levels and employed mathematical functions, all standard channel models target the generation of a commonly structured channel impulse response comprising eight shared components. Furthermore, based on the affinity, we propose a research direction to develop unified mmWave channel generation for WPAN, WLAN, and CN, where channel simulations for the three scenarios can be conducted in an identical framework. Our experimental results shed light on the feasibility of the proposed research direction and highlight the challenges and opportunities.