Channel Characteristics of Dynamic Off-Body Communications at 60 GHz Under Line-of-Sight (LOS) and Non-LOS Conditions

Abstract

This letter investigates the first-order characteristics of dynamic off-body communications channels at 60 GHz. In particular, we have studied signal propagation from a chest-worn millimeter-wave transmitter as an adult male walked toward and then away from a hypothetical base station. The mobile line-ofsight (LOS) and non-LOS (NLOS) channel measurements have been conducted in a diverse range of environments, including a hallway, an open office, an anechoic chamber, and an outdoor car park. In this study, we have decomposed the received signal into its path loss, large-scale, and small-scale fading components. The large-scale fading has been modeled using the gamma distribution, while the Rice and Nakagami-m distributions have been employed to describe the small-scale fading observed in the LOS and NLOS channel conditions, respectively. The results have shown that the estimated path loss exponents for the anechoic chamber and car park environments were greater than those obtained for the hallway and open office environments for both the LOS and NLOS walking scenarios. Across all environments, it was found that the gamma distribution provided an adequate fit to the large-scale fading. Additionally, the Rice and Nakagami-m distributions were found to well describe the small-scale fading for the LOS and NLOS walking scenarios, respectively.Index Terms-Large-scale fading, millimeter-wave (mm-wave) communications, off-body communications, path loss, small-scale fading.

Application of Flexible Numerology to Blockage Mitigation in 5G-mmWave Networks

“…Our claim is that different numerologies will fare better under blockage conditions, and hence may be used to improve the mmWave user performance. We verify our claim by analysing the mmWave link performance using the numerologies available for 5G mmWave systems, under a range of blockage scenarios, defined and empirically-validated in [10]. Our results show that there is a trade-off between the high transmission efficiency, achieved with longer TTIs, and the high probability of LOS transmission, achieved using shorter TTIs.…”

“…The AP is installed at a height h A above the UE level, as illustrated in Figure 2a. This setup shall generalise over the two deployment scenarios considered in [10], but is also in-line with the 3GPP-defined scenarios for 5G mmWave system evaluation [27]: indoor office with ceiling-mounted access points and outdoor car-park with lamppost mounted access points. We assume the resource allocation decision in the AP is made every τ ms, which we refer to as the scheduling interval (SI).…”

“…For modelling of the mmWave signal propagation, we consider the experimentally-validated channel model proposed in [10]. The model consists of the path loss and the composite Gamma-Nakagami-m fading, whose parameters take one of two values depending on whether the user body blocks the LOS path, meaning that the model parameters change with the random blockage state.…”

“…The model consists of the path loss and the composite Gamma-Nakagami-m fading, whose parameters take one of two values depending on whether the user body blocks the LOS path, meaning that the model parameters change with the random blockage state. The fading and path-loss coefficients for that model were estimated from the experimental data collected for a mmWave AP operating at 60 GHz in [10].…”

Fading Characterization of UE to Ceiling-Mounted Access Point Communications at 60 GHz

“…A number of studies have been performed to investigate the statistical characteristics of the small-scale fading experienced in indoor mm-wave communications channels at 60 GHz [3][4][5]. For example, the small-scale fading observed in off-body communications channels was characterized in [3] using the Rice and Nakagami-m distributions, while in [4] a similar methodology was used to study UE-to-eNB channels. In [5], it was found that the Rice fading model provided the best fit to the measurement data collected in LOS conditions within an indoor laboratory environment.…”