GHz In Indoor Environment Research Articles

LoS Theoretical and Experimental MIMO Study from 1–40 GHz in Indoor Environments

In this work, line-of-sight multiple-input multiple-output (MIMO) measurements in the frequency range from 1 GHz to 40 GHz are presented for an indoor environment in the scope of new 5G bands. For the sake of comparison, the measured radio channels are reproduced with great accuracy using ray-tracing techniques by tuning all propagation mechanisms. The relative received power, root mean square of the delay spread (RMS DS) and K-factor provide an insight of how propagation behaves in indoor scenarios within a large and contiguous frequency band. Results show that a decay factor behaves nearly constant with frequency and the RMS DS is quite sensible to frequency. From these results, faithful one-slope 5G models are proposed. Finally, the contribution of the simulated propagation mechanisms to the radio channel is investigated which suggests that the simulation of the low-mmW radio channel can be simplified.

Large-Scale Channel Modeling and Measurements for 10 GHz in Indoor Environments

With the advent of 5G mobile communication and researches into the propagation of large-scale channel modeling for frequencies above 6 GHz, measurement investigation was performed at 10 GHz with horn-type directional antennas in a corridor and a computer room within the Electrical and Computer Engineering Laboratories’ first floor, at Federal University of Pará (UFPA), Brazil. This paper presents data obtained through experimental work, channel modeling with co-polarization V-V and H-H and cross-polarization V-H in line-of-sight (LOS) or non-line-of-sight (NLOS) conditions. The large-scale close-in reference is sustained by a comprehensive analysis, considering propagation mechanisms such as reflection and diffraction. Results demonstrate that the established model had inferior standard deviation in relation to measured data, proving itself more significant to propagation in indoor environments.

Algorithms for Estimation of the Coverage Area and Low Blocking Probability Model Log-Normal Shadowing for 2.4 GHz and 5 GHz in Indoor Environments

Background/Objectives: In designing WLAN networks is difficult to determine exactly the maximum range of the signal radiated by an Access Point, due to the random behavior of the signal received power and receiver sensitivity. The aim of this paper is to develop an algorithm estimate the probability of Court and the coverage area for an Access Point (AP) in the 2.4GHz and 5GHz bands. Methods/Statistical Analysis: For estimating the outage probability and the coverage area, two routines in Matlab for each frequency band supported on the propagation model Log-Normal Shadowing Path Loss developed, which allow decompose the received power at an average power and attenuation term shadow. Topic Relevance: Although there have been various related design WLANs work, no evidence of an algorithm to estimate the coverage area and the likelihood of court, considering it was found that, in most cases, the estimation of these parameters it is performed graphically and by using software tools on a plane set by the designer. Aspect by which developed in Matlab routines may be used in future research related to the design of WLANs. Results: Based on the results it was evident that it is possible to predict the area of coverage and outage probability for the 2.4GHz and 5GHz according to the transmission power, the detection threshold of the receiver, the probability estimated cut and environment characterization between the AP and the receiver, either free space or obstacles, supported using a shadow model attenuation. Additionally, routines allowed the generation of curves describing the behavior of area coverage and outage probability in terms of percent, depending on the radius of coverage, frequency band and environmental conditions, with 95% confidence. Application/ Improvements: The developed routines can be used as support tools in future research. Keywords: Coverage Area, Interference, Outage Probability, Reception Power, WLAN Networks

Experimental Study of MIMO-OFDM Transmissions at 94 GHz in Indoor Environments

Millimeter wave (mm-wave) frequencies have been proposed to achieve high capacity in 5G communications. Although meaningful research on the channel characteristics has been performed in the 28-, 38-, and 60-GHz bands in both indoor and short-range scenarios, only a small number of trials (experiments) have been carried out in other mm-wave bands. The objective of this paper is to study the viability and evaluate the performance of the 94-GHz frequency band for MIMO-OFDM transmission in an indoor environment. Starting from a measurement campaign, the performance of MIMO algorithms is studied in terms of throughput for four different antenna configurations.

Characterization of on‐human‐body UWB radio propagation channel

AbstractWireless body area network (WBAN) has begun to receive attention recently. Ultra wideband (UWB) is a promising technology for WBAN applications. This article presents the results of UWB radio channel measurements performed on human bodies from 3.1 to 10.6 GHz in indoor environments. The measurements were devised to generate the radiographs of path loss and delay spread for the first time. The radiographs contain both qualitative and quantitative information on the channel. They clearly display the influence of the body on the channel and thus reveal where the network nodes should be strategically placed on the body in the design of the UWB WBAN systems. They directly give such channel parameters as path loss and delay spread. They also reflect variations of the channel on and in close proximity to the body. In addition, the measurements were made in an anechoic chamber to expose the impact of the body and to study the effect of different environments on the channel. It is shown that for the UWB channel on the body the path loss exponent n = 2.7 can be used, while for the UWB channel through the body the path loss exponent increases to n = 3.7. The maximum value of the rms delay spread is 12 ns. The rms delay spread values are less than 6 ns 50% of the time. The number of multipath components increases with the separation between transmit and receive antennas. Because of the nonreflecting mechanism, the path loss is larger and the delay spread is smaller in the anechoic chamber environment. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1365–1371, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22411

Indoor propagation characteristics at 5.2GHz in home and office environments

This paper presents results of continuous wave and swept frequency response measurements over the frequency range of U-NII lower and middle bands from 5.15GHz to 5.35GHz in indoor environments. From the continuous wave measurements at 5.2GHz, the excess path loss, and the statistical characteristics of the temporal and spatial fading were found. By sweeping the frequency over the band, envelope correlation as a function of frequency was found and the coherence bandwidth (CBW) was determined from the envelope correlation. Using a channel model, the CBW was used to evaluate RMS delay spread. The dependence of CBW on the antenna polarization was simulated and compared with the measurement results. The influence of room size and separation of transmitter and receiver for LOS paths on RMS delay spread was discussed.

Comparative study of millimeter wave propagation at 30 GHz and 60 GHz in indoor environment

The millimeter wave band appears to be a favourable choice for personal wireless communication systems for indoor environment, as it meets the requirements for sufficient bandwidth, small terminal dimensions and sporadic usage for commercial applications. In this paper measurements of millimeter wave propagation in both 30 GHz and 60 GHz bands, are presented in a comparative way. The topology of measurements covers both a line-of-sight situation and also a case where a direct path between transmitter and receiver does not exist. Although the second case does not seem obvious for outdoor applications in these frequencies, in indoor environment the multipath signals produced by objects like walls, doors, furniture etc., can be utilised in order to overcome the man-made shadowing. Both slow and fast fading characteristics of the received signal are studied and the measurements are modelled by the conventional Rician and Rayleigh distributions. Both frequency bands offer advantages for usage in in-house wireless communication systems. Although in 30 GHz band the coverage area is bigger than in 60 GHz (with the same transmitting power), frequency reuse is easier in 60 GHz band. because even if millimeter waves ‘escape’ through ‘windows’, the specific attenuation due to atmospheric oxygen (15 dB/km) at 60 GHz eliminates the interference between communication channels in neighbouring buildings.