Spectrum Coexistence, Network Dimensioning, and Cell-Free Architectures in 5G and 5G-Advanced Wireless Networks

Fifth-generation (5G) wireless networks introduce new architectural paradigms, spectrum usage models, and optimization challenges to support enhanced mobile broadband, massive machine-type communications, and ultra-reliable low-latency communications. This survey provides a comprehensive overview of key technologies and design challenges in 5G systems, with a focus on spectrum coexistence and interference management, network dimensioning and planning, cell-free massive MIMO architectures, fronthaul-aware user management, and power allocation strategies. Representative analytical, simulation-based, and optimization-driven approaches are reviewed, fundamental trade-offs are highlighted, and open research challenges relevant to 5G-Advanced and beyond are identified.