063 - RIS-aided wireless localization and mapping
Propagation at radio frequency suffers from obstructions due to objects blocking Line of Sight (LOS) path between the transmitter and the receiver. To increase the probability of LOS from a sufficient number of transmitting points, PNT systems imply sufficient densification and time synchronization. In spite of all these, many blind spots continue to degrade the positioning performance.
A solution is to deploy dedicated pseudolites systems such as e.g., Locata, which have a proven record of working with good performance. The dependency on the LOS path can also be reduced through disruptive initiatives such as multipath-aided localization by exploiting man-made structures with programmable reflection and refraction properties and embedded in the built environment called Reconfigurable Intelligent Surfaces (RIS). RIS is a novel technology to construct radio environments by deploying a programmable surface able to reconfigure the wireless propagation environment by carefully tuning the phase shifts of a large number of low-cost passive reflecting elements. In more simple words, RIS can control the direction of radio wave reflection. RIS added values are as follows: direction can be dynamically reconfigured via SW without changing the pointing of the antenna; they are passive elements that can be used primarily for improving communication services but also exploited for positioning, therefore they are expected to be more cost efficient; no extra costs are imposed on the user equipment as there is no need for additional dedicated HW as is the case with pseudolites; and no additional regulatory aspects and minimal energy consumption due its passive nature. Lastly, based on the fundamental operating modes, a RIS can act as transmitter, receiver, or as a reflector, where the direction of the reflected wave is no longer specular according to natural reflection laws but steerable.
The objective of the proposed activity is to demonstrate metamaterials can be used to control the EM environment to achieve accurate multipath-aided positioning with low resources. Through this activity several important outstanding challenges for RIS-based localization are expected to be overcome: signalling and system architecture, RIS control (i.e. steering the incident beams in a direction of interest), waveform design, and localization algorithms.
RIS is a topic that is gaining more and more notoriety in the last years, both in the academic environment (Heriot University, University of Glasgow – UK, University of Trento – IT, AIT Austrian Institute of Technology – AT, Linkoping University – SE, etc.) and industry (Nokia, Montimage GmbH, etc.). Nevertheless, RIS-aided localization has never been studied in a configuration with a uniform planar array nor demonstrated even in laboratory environment. This activity could also contribute to the prototyping of a novel 3D mapping and localization system.
Ultimately, this activity, based on field trials, will attempt to validate the hypothesis that positioning with a single transmitter can be performed by exploiting RIS surfaces and synthetic NLOS signals.
The tasks to be performed will include:
- Investigate use cases (localization, sensing, etc.) and deployment scenarios (indoor, urban)
- Study channel models, RIS components (active vs passive vs reflective pattern), beam management, control of RIS, waveform design, etc.
- Develop and test protocol for controlling the RIS, localization algorithm(s)
- Test the proof of concept in lab environment based on measurement campaign
As a result, the TRL at the end of the activity should be 4.
The main outputs of the activity will consist of:
- Localization algorithms for RIS-aided positioning
- End-to-end Breadboard for data sets for RIS-aided positioning
- Demonstrate RIS-aided positioning based on field campaigns carried out in lab environments