Setting 6G KPIs for Diverse Future Use Cases: A Comprehensive Study of Emerging Standards, Technologies, and Societal Needs

The next generation of wireless communication, 6G, promises a leap beyond the advances of 5G, aiming not only to increase speed but also to redefine how people, machines, and environments interact. This paper examines the evolution from 5G Advanced to 6G through a detailed review of 3GPP Releases 15-20, outlining the progression from enhanced mobile broadband to intelligent services supporting holographic communication, remote tactile interaction, and immersive XR applications. Three foundational service pillars are identified in this evolution: immersive communication, everything connected, and high-precision positioning. These advances enable transformative use cases such as virtual surgery, cooperative drone swarms, and AI-driven agriculture, demanding innovations in spectrum utilization (including sub-THz bands), AI-native network architectures, and energy-efficient device ecosystems. Future networks are expected to deliver peak data rates up to 1~Tbps, localization accuracy below 10~cm, and device densities reaching 10M/km2, while sustaining end-to-end latency under 1~ms. Across Releases 15-20, 3GPP has progressively standardized capabilities for XR, positioning, scheduling, and sustainability, while initiatives such as RedCap, Ambient IoT, and NTN extend connectivity toward global, low-power, and cost-effective coverage. Supported by programs like Hexa-X and the Next G Alliance, 6G is positioned as a fundamental redesign of wireless communication centered on intelligence, adaptability, inclusivity, and sustainability.