Energy efficiency is becoming a key design factor in most industries, including telecommunications. The use of traditional energy sources for network and terminals is being reconsidered and alternative solutions are being studied, especially energy harvesting mechanisms from ambient energy. In particular, RF Energy Harvesting is considered as a promising technique for future 5G systems. This paper presents 5G requirements and use cases suitable for RF energy harvesting. It reviews Energy Harvesting techniques considered for 5G and considers energy harvesting constraints and research axis at terminals level and at network level.
