Resumen
Next-generation technologies are being tried to develop for 5G wireless cellular networks nowadays by many researchers. Some key technologies provide significant improvements for 5G systems in terms of huge capacity, higher data rate, signaling overhead on the network and energy-spectral efficiency. But these technologies also bring along critical issues for 5G systems. In this paper, these major problems of 5G networks are discussed in terms of scarcity radio frequency spectrum, inter-antenna synchronization, antenna deployments in cells, network and traffic management, cost and workload. Also these challenges are expressed, presented and discussed in each section to provide prior knowledge and perspective for 5G network designers and researchers.