6G RIS in Indoor Environments: Assessment of Exposure Variability in Human Users and Non-Users

The aim of the present work is to assess the exposure of human users and non-users in indoor scenarios due to novel technology that will be integrated in 6G network in order to overcome the obstacles in NLOS area: Reconfigurable Intelligent Surface (RIS), here tuned in FR1-band. The exposure assessment was conducted in two simplified indoor scenarios, single room and office, where the transmission angle of the RIS were varied mimicking the RIS following the user, and the Specific Absorption Rate (whole-body and brain SAR) were calculated. Five human models from Virtual Population (ViP) were considered differing between each other for anatomical characteristics. <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm { SAR}}_{\mathrm { wb}}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm { SAR}}_{\mathrm { brain}}$ </tex-math></inline-formula> results, studied in terms of peak values, cumulative distribution functions (CDFs) and spatial maps, showed higher <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm { SAR}}_{\mathrm { wb}}$ </tex-math></inline-formula> values in adults compared to children, while <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm { SAR}}_{\mathrm { brain}}$ </tex-math></inline-formula> peaks were more pronounced in child models. The study also revealed that there are few cases in which the exposure of non-user could be higher than the user. Moreover, the CDFs demonstrated that, for all the considered models, the probability that very low <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm { SAR}}_{\mathrm { brain}}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm { SAR}}_{\mathrm { wb}}$ </tex-math></inline-formula> levels occur is noticeably high. However, in general all the results are well below the ICNIRP Guidelines limits.