Editorial of ETT special issue: emerging topics in device to device communications as enabling technology for 5G systems

[Excerpt] The growing demand for mobile data traffic and the proliferation of applications requiring high data rates have raised the need for the definition of new standards in the mobile market. Next generation mobile and wireless communications systems will have to respond to an avalanche of traffic, an explosion in the number of connected devices, and a large diversity of use cases and requirements. Towards this aim, the fifth generation (5G) systems will not only be a sheer evolution of the current systems but, more significantly, a revolution in information and communications technology with innovative network features