Photonics functionalities for 5G and beyond
The wireless communication systems are witnessing an impressive increase in transported data traffic, especially with the development of 5G systems that aims at ensuring very broad bandwidth to the single mobile users and at connecting everything to the internet. Recently, photonics is being investigated for implementing different functions in the microwave world, thanks to its low noise (in particular, low phase noise), large bandwidth, an easy tunability. Therefore, in several recent demonstrations, photonics is being used not only for signal transportation (radio-over-fiber systems), but also for developing the entire wireless transceivers, from the RF signal generation to its reception, including beamforming. This tutiorial reviews the photonic-based functionalities and technologies useful in wireless transceivers, and reports on few examples of photonics-based transceivers for fiber-wireless networks.