C. Liaskos - Personal web page                     @ UoI

Abstract: 

In a usual scenario of wireless communication, electromagnetic waves emitted from user devices scatter chaotically in space, without any control over the physical propagation process, except for the wireless channel endpoints. This has been the norm in wireless communications, where the objects in-between devices are oblivious to the communication process.

There are many security-related problems rising with this norm, with one of them being eavesdropping. People and as a result, wireless devices, share the same medium to transmit data. Therefore, anyone, who may not be a part of a transaction, can try to get a hold of the data that someone else is transmitting. A closely related problem that regular wireless propagation environments are facing, is interference. Yet again, the problem is the sharing of the same medium freely–and potentially selfishly–resulting in network slow-down.

Those issues are caused by the very nature of electromagnetism that dictates the way a wireless emission gets scattered in a space, even if there is no intention for malevolent exploitation. The situation is aggravated in the presence of malicious users, who have as an ultimate goal to disrupt/eavesdrop communication channels, often employing ingenious ways in doing so. Over the years, several steps have been made towards more secure, disruption-free ways of communication, employing robust resource sharing mechanisms and encryption. However, if the physical wireless propagation allows it, mischievous individuals can in principle circumvent any security mechanism.

Programmable wireless environments (PWE) introduce novel capabilities in security, by constituting the wireless propagation controllable in a deterministic manner. They are enabled by coating planar objects in a space with HyperSurfaces, a novel combination of metamaterials and well-defined networking and programming interfaces. Operating by the Huygens principle, HyperSurfaces manipulate impinging waves by altering their power, direction, polarization and phase. Inter-networking capabilities allow them to exchange information and deploy custom end-to-end air-routes that exemplary avoid unintended users, or at least ensure destructive wave super-position in their vicinity.

Illustration of the programmable wireless environment concept. The electromagnetic behavior of walls is programmatically changed to maximize data rates (green use-cases), wireless power transfer (orange use-case), negate eavesdropping (purple use-case), and provide electromagnetic shielding (red use-case).

In a nutshell

The programmable environment concept abstracts the underlying physics of wireless propagation, exposing a software programming interface to control it instead. Thus, the physics behind wireless propagation are brought into the realm of software developers, treating the electromagnetic behavior of objects with simple commands, as below:

Software commands are combined and applied locally on walls to achieve the user objectives.

Essentially, the HyperSurface-coated objects are treated as "routers," which can forward or block electromagnetic waves in a manner very similar to the concept of routers and firewalls in wired networks. Connecting devices becomes a problem of finding a route connecting HyperSurfaces, subject to performance requirements and useraccess policies.