This chapter introduces new requirements for fifth-generation (5G) as far they can be interpreted from various relevant sources. These key sources of information are presented as available now, and based on this information, the requirements are interpreted for the already known and foreseen statements, e.g. via the radio section of International Telecommunications Union, Third Generation Partnership Project, and other entities involved with the standardization of 5G. The chapter also presents the aspects of the interworking of 5G services with legacy systems, presenting general considerations of cooperative functioning of 5G and other relevant systems. It discusses the performance aspects of the 5G in fixed and wireless environment, along with the possibilities and constraints, including the performance in practice now and via expected standardized features. Finally, the chapter provides a discussion on the impacts of requirements, including impact analysis for the technologies and businesses.