Beyond 5G - wireless data center connectivity

With the digitalization of industry and society, data centers have grown into an essential key strategic infrastructure, centralizing the processing, storage and distribution of vast amounts of information. Through continuing centralization, their size grows ever larger, while at the same time they need to remain flexible and dynamic to adapt to the temporary nature and diverse requirements of many tasks. Modular data centers can fulfil this requirement, allowing quick deployment and provisioning, while being highly reconfigurable - however, in such data centers interconnectivity is a complex and difficult issue. Wired connections based on optical fibers are the standard in data centers, but come at a significant cost and lack reconfigurability. The introduction of wireless connectivity at millimeter and tera-Hertz frequencies offers similar capacities, while allowing dynamic and re configurable deployment and wireless or hybrid data center architectures have been suggested. In this context, the innovations in high capacity millimeter wave communications and in the convergence of optical and wireless networking developed for 5G mobile networks may offer a potential technology candidate for high-density and high-capacity data center network deployments. Such networks allow the layout and topology of the network to be changed on demand and to adapt to the changing needs of different applications, creating a data center network that matches the multi-purpose nature of the computation and storage hardware. In this paper, the recent trends in wireless technologies for data centers are reviewed and connected to the innovations of optical and wireless convergence seen in 5G networks, perceiving a data center network that is better able to cope with the demanding requirements in terms of network reconfigurability, installation and running cost, as well as power consumption and cooling efficiency.