Millimeter-wave (mm-wave) spectrum unravels the humongous and accelerating demand for wireless data rates and, therefore, it will be a fundamental ingredient of the fifthgeneration (5G) wireless technology. In case of mm-wave access links, humans are the most noticeable blockers of electromagnetic waves from access points to mobile stations and hence cause temporal variation in the radio channel. This paper presents human blockage measurements in the anechoic chamber at 15, 28 and 60 GHz frequencies employing 15 human subjects of different sizes and weights. An effective three-dimensional human blockage model as a double-truncated and absorbing multiple knife-edge (DTMKE) scheme is also proposed. By calculating diffraction from the DTMKE, the frequency, body orientation and antenna height dependency of the blockage are most accurately reproduced compared to the existing models, such as absorbing double knife-edge model and third generation partnership project (3GPP) human blockage model. The results demonstrate that the losses are proportional to the cross-section of the human body with respect to the radio link. Furthermore, the blockage loss decreases as the height of the transmitting antenna increases.Index Terms-Millimeter-wave (mm-wave), fifth-generation (5G), three-dimensional (3D), human blockage.
Accurate site-specific radio propagation simulations provide an important basis for cellular coverage analysis. The quality of these simulations relies on the accuracy of environmental description and electrical properties of constituent materials. This paper presents a novel method of on-site permittivity estimation. The method utilizes an accurate geometrical database of the environment for identifying flat and smooth surfaces producing reflections. The method exploits a limited number of on-site channel sounding to extract reflected multipaths, and compare them with ray-tracing based on the environmental database. The permittivity of the identified reflecting surfaces is estimated by solving an inverse reflection problem. The method was experimentally tested with a limited radio channel measurements at 60 GHz in a large empty office room. The identified reflecting surfaces are classified according to their mean permittivity estimates, showing their consistency with physical material evidence and the permittivity database in the ITU recommendation. The estimated permittivity values are visualized as a three-dimensional map, giving an intuitive understanding of materials constituting the environment. Our work demonstrates on-site permittivity estimation and material classification without the need for isolated measurements of composite materials in an anechoic chamber or in-situ measurements of built environments.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.