Path Loss Analysis Research Articles

Path Loss Analysis and Transceiver Development for Human Body Communication-Based Signal Transmission for Wearable Robot Control

Human body communication (HBC) technology is attracting a lot of attention for monitoring vital data and controlling wearable robot. In this paper, we focused on electroencephalogram (EEG) signal transmission from head to wrist in the 10–60 MHz HBC band. This is based on an idea to transmit an EEG signal to control a wearable robot. First, we clarified the basic transmission mechanism and characteristics using a highly simplified human body model. Next, we performed a detailed path loss analysis by finite difference time domain simulation using an anatomical human body model with various postures. Based on the analysis results, we identified the optimum transmitter position on the head and developed an impulse radio transceiver for verifying the feasibility of the technique. The results show that the developed transceiver can provide a data rate of 10 Mbps and the bit error rate can be kept below 10−3 for transmitting the EEG signals from the head to the wrist. Experimental validation with a bio-equivalent gel phantom also demonstrated high feasibility of transmitting the EEG signals along the human arm.

Mobile 4G LTE Networks Mobility and Coverage for Some Locations in Ibadan Using Path Loss Analysis

The recent migration of most GSM service providers’ networks in Ibadan from 3G to 4G, in preparation for the deployment of 5G technology in the nation necessitated the need to re-examine the GSM networks’ mobility and coverage within the micro cells in-between a Base Station and a Mobile Station. This attempt is aimed at using existing Path Loss Propagation Models in proffering solutions to the negative consequences usually associated with call drops in the Urban and Suburban Areas of Ibadan due to inability of channels to handover as a result of path loss. The path loss (dB) analysis was carried out by measuring the Received Signal Strength RSS (dBm) at distances ranging from 0.05 km to 4 km in-between Base Stations and Mobile Stations using the factory fitted installed RSS software on Android phones. These measurements were taken for three weeks within the urban and suburban areas of the University of Ibadan campus, and its neighborhood community of Agbowo for ten selected existing Base Stations from four of the nationwide GSM Service Providers (SP1, SP2, SP3 and SP4) in Nigeria. The variation of path loss with the RSS for GSM Service Provider (SP1) propagating at 955MHz (reference distance of 0.05km), 1850MHz and 2120MHz, were 66.03 dB, 71.77 dB and 72.96 dB, respectively. However, at 4 km the path loss had risen to 101.59dB for 955MHz, 103.81dB for 1850MHz and 105dB for 2120MHz. Also, the path loss for the GSM service provider (SP2) propagating at 960MHz (reference distance of 0.05km), 1865MHz and 2150MHz were 66.07 dB, 71.84 dB and 73.08 dB, respectively. Moreover, in a similar manner to the SP1 service provider, at 4 km the path loss had risen to 104.14dB for 960MHz, 109.9dB for 1865MHz and 111.14dB for 2150MHz. Furthermore, the path loss for the GSM service provider (SP3) propagating at 950MHz (reference distance of 0.05km), 1835MHz and 2130MHz were 65.98 dB, 71.70 dB and 73.00 dB, respectively. Likewise, as was in the case of the SP1 and SP2 Service providers, the path loss at 4 km had risen to 104.05dB for 950MHz, 109.76dB for 1835MHz and 111.06dB for 2130MHz. Also, the path loss for the GSM service provider (SP4) propagating at 940MHz (reference distance of 0.05km), 1880MHz and 2140MHz, were 65.47 dB, 71.46 dB and 72.23 dB, respectively. Moreover, the path loss at 4 km had risen to 103.53dB for 940MHz, 109.52dB for 1880MHz and 110.29dB for 2140 MHz as was the case with the other GSM Service providers (SP!, SP2 and SP3) considered .Thus, the path loss increases with distance within the microcells of base stations. However, the path loss model with minimum path loss (dB) at a given distance enhances good coverage and handover postponement. Moreover, the mean square error values used in obtaining the accuracy between the measured and the Empirical models were 17.15dB, 59.69dB, 48.46dB, 60.52dB and 40.07dB for the C-model, Cost-OH, Sub-O, Lee-model and experimental model, respectively. . Key words: GSM networks, Base station, Mobile station, Signal strength, GSM service provider

Method for Estimating Optimal Position of S-Band Relay Station through Path Loss Analysis in an Outdoor Environment

This article investigates a novel estimation method to optimize the position of a relay station of the S-band telemetry system in outdoor environments. To determine an optimal relay station position, complex terrain surface and buildings near the Naro Space Center are included in the EM (Electromagnetic) simulation. The optimal relay station position is then determined using the estimation method by comparing the path losses from the rocket to the main station and some candidate positions of the relay station. To better understand the path loss, the ray analysis is also conducted, and the result demonstrates that once the rocket altitude to be covered by the relay station is determined, it is possible to find the optimum position of the relay station.

On the Energy Efficiency of Massive MIMO Systems With Low-Resolution ADCs and Lattice Reduction Aided Detectors

As an effective technology for boosting the performance of wireless communications, massive multiple-input multiple-output (MIMO) systems based on symmetric antenna arrays have been extensively studied. Using low-resolution analog-to-digital converters (ADCs) at the receiver can greatly reduce hardware costs and circuit complexity to further improve the energy efficiency (EE) of the system. There are significant research on the design of MIMO detectors but there is limited study on their performance in terms of EE. This paper studies the effect of signal detection on the EE in practical systems, and proposes to apply several signal detectors based on lattice reduction successive interference cancellation (LR-SIC) to massive MIMO systems with low-precision ADCs. We report results on their achievable EE in fading environments with typical modeling of the path loss and detailed analysis of the power consumption of the transceiver circuits. It is shown that the EE-optimal solution depends highly on the application scenarios, e.g., the number of antennas employed, the cell size, and the signal processing efficiency. Consequently, the signal detector must be properly selected according to the application scenario to maximize the system EE. In addition, medium-resolution ADCs should be selected to balance their own power consumption and the associated nonlinear distortion to maximize the EE of system.

Wireless Underground Communications in Sewer and Stormwater Overflow Monitoring: Radio Waves through Soil and Asphalt Medium

Storm drains and sanitary sewers are prone to backups and overflows due to extra amount wastewater entering the pipes. To prevent that, it is imperative to efficiently monitor the urban underground infrastructure. The combination of sensors system and wireless underground communication system can be used to realize urban underground IoT applications, e.g., storm water and wastewater overflow monitoring systems. The aim of this article is to establish a feasibility of the use of wireless underground communications techniques, and wave propagation through the subsurface soil and asphalt layers, in an underground pavement system for storm water and sewer overflow monitoring application. In this paper, the path loss analysis of wireless underground communications in urban underground IoT for wastewater monitoring has been presented. The dielectric properties of asphalt, sub-grade aggregates, and soil are considered in the path loss analysis for the path loss prediction in an underground sewer overflow and wastewater monitoring system design. It has been shown that underground transmitter was able to communicate through thick asphalt (10 cm) and soil layers (20 cm) for a long range of up to 4 km.

移动场景下无线紫外光通信单次散射路径损耗分析

移动场景下无线紫外光通信单次散射路径损耗分析

Ultra-Dense Networks: A Holistic Analysis of Multi-Piece Path Loss, Antenna Heights, Finite Users and BS Idle Modes

We discover a new capacity scaling law in ultra-dense networks under practical system assumptions, such as a general multi-piece path loss model, a non-zero base station to user equipment antenna height difference, and a finite user equipment density. The intuition and implication of this new capacity scaling law are completely different from those found in the year 2011. That law indicated that the increase of the interference power caused by a denser network would be exactly compensated by the increase of the signal power due to the reduced distance between transmitters and receivers, and thus, network capacity should grow linearly with network densification. However, we find that both the signal and interference powers become bounded in practical ultra-dense networks, which leads to a constant capacity scaling law. Moreover, our new discovery on the constant capacity scaling law indicates three network optimization problems respectively for base station deployment, user equipment scheduling and base station coordination. These three optimization problems are justified and solved in this paper, shedding new light on the deployment and optimization of ultra-dense networks.

Statistical Inter-Floor Radio Channel Model

Statistical inter-floor radio channel model is proposed, based on extension of the existing single-floor Saleh–Valenzuela model. Instead of cluster of rays, the term super-cluster is introduced consisting of a group of clusters disposed just like on single-floor channel impulse response. More super-clusters make inter-floor channel impulse response where Poisson distribution controls their number, exponential distribution controls their mutual disposition and one specific statistic distribution controls their amplitudes taken from separate inter-floor UTD path-loss analysis. The model resumes existing internal structure of impulse responses. It is additionally simplified on a way that triple Poisson process becomes a double one. This model became modified version of Saleh–Valenzuela model, suitable for assessment of inter-floor as well as single-floor channel characteristics. The model accuracy is tested with results obtained by VNA measurements. Analysis showed that this new model may be sufficiently accurate tool for simulation of single-floor and inter-floor channels but acting as a single model. It is necessary just to change average number of clusters which makes difference between the models, this procedure even has a physical sense.

Path Loss Analysis Considering Doppler Shift Effect on Cellular Communication for Connected Car Application at Rural Area

In this paper, the study on the loss of pathways in cellular communication is carried out by experimentation and simulation on three different modules in rural areas. These three-communication module has different carrier frequencies to determine the effect of the doppler shift to the loss of the moving vehicle communication path. The simulation and experimental output are compared to improve the accuracy of these studies. Simulation studies are based on the proposed model for the modified path loss. For the experimental portion, the path loss was determined based on two things: the measured received power on communication modules antenna and transmit power from base station. From this study, the best selection of the communication module is selected for use in connected cars by considering the fading effect of doppler shift.

Path Loss Analysis Considering Doppler Shift Effect on Cellular Communication for Connected Car Application at Rural Area

In this paper, the study on path loss of cellular communication is conducted by experiment and simulation on three different communication modules at rural area. This three-communication module will have different carrier frequency to determine the effect of doppler shift to communication path loss of moving vehicle. To enhance the accuracy of these studies, both simulation and experiment output will be compared. Simulation studies will be based on proposed modified path loss model. For the experimental portion, the Path Loss will be determined based on two things: the measured received power on communication modules antenna and transmit power from base station. From this experiment, the best selection of communication module by considering the fading effect from doppler shift is selected to be used in connected car.

Enabling connectivity for tactical networks in mountainous areas by aerial relays

A general modeling framework for realistic performance evaluations of tactical mobile ad-hoc networks deployed in mountainous areas is presented. The framework is easily extensible, and can be eventually automated. It can be also used to generate data for other network simulators. The framework utilizes the freely downloadable high resolution 3D terrain data to define time dependent trajectories of network nodes. The node speeds and directions are linked to the terrain profile which extends the previously proposed mobility models. The path-loss analysis along the node trajectories revealed the need for aerial relays to enable full network connectivity at all times. The network consisting of 5 cluster heads and a single stationary relay is considered as a case study. The relay location and its antenna height are optimized to achieve the line-of-sight connectivity over the whole mission duration. The antenna radiation pattern at the relay is incorporated in the analysis. The resulting star network topology is used by the cluster heads to broadcast their packets to all other cluster heads. Several relaying schemes including the amplify-and-forward and the decode-and-forward relaying are studied together with the go-back-N retransmissions to achieve the reliable data transfer.

The Design and Implement of Propagation Path-Loss Model over Sea-Surface under HF

A new algorithm “Propagation Path-Loss Model” (PPLM) is introduced in this paper. As a correction coefficient and equivalent reflection coefficient are introduced to simulate the reflection loss of calm and rough sea-surface, a mathematical prediction model of sea-surface propagation is devised. This model focus on the analysis of propagation path and transmission loss of skywave, including the propagation loss in free space and ionosphere and reflection loss over the sea-surface. PPLM permits calculating the propagation losses and evaluating propagating capacity of a certain environment by predicting the propagation distance and maximum hops of signal at a certain power. It also can be utilized to predict the communication time based on a geometrical model of skip zone. All the implements indicates that the model is effective and functional.

Path-Loss Estimation for Wireless Cellular Networks Using Okumura/Hata Model

In cellular networks, accurate path-loss estimation is highly desirable not only to improve the performance but also to realize precise estimation of financial feasibility. In other words, while accurate path-loss estimation helps to achieve an acceptable performance and reasonable cost, inaccurate path-loss estimation would either lead to degrade the performance, or increase the cost. Different models were introduced in the literature for achieving accurate path-loss estimation. One of theses models is the Okumura/Hata model which is recommended for being used to estimate the path-loss in the cellular systems that employing micro-cells. It is characterized by its suitability for being used in a variety of environments. The main objective in this paper is to provide a guide line for path-loss estimation analysis using Okumura/Hata model. Matlab software was used to perform this analysis. Compared with free space model in which frequency and separation distance are the only contributors for path-loss, more accurate estimation can be achieved when Okumura/Hata model is used as it includes further correction factors, such as mobile station antenna height and base station antenna height.

Analysis of E-Band Path Loss and Propagation Mechanisms in the Indoor Environment.

Millimeter-wave transceivers will feature massive phased-array antennas whose pencilbeams can be steered toward the angle of arrival of the propagation path having the maximum power, exploiting their high gain to compensate for the greater path loss witnessed in the upper spectrum. For this reason, maximum-power path-loss models, in contrast to conventional ones based on the integrated power from an omnidirectional antenna, may be more relevant. Yet to our knowledge, they do not appear in the literature save for one reference. In this paper, we compare both model types at 83.5 GHz for four indoor environments typical of hotspot deployments in line-of-sight (LOS) and non-LOS conditions up to a range of 160 m. To fit the models, we conducted a measurement campaign with over 3000 different transmitter-receiver configurations using a custom-designed channel sounder capable of extracting the delay and 3-D angle of arrival of the received paths with super-resolution. The models are supported by a detailed analysis of the propagation mechanisms of direct transmission, reflection, and knife-edge diffraction to shed light on their interplay in the E-band regime.

Characteristics of the polarised off-body channel in indoor environments

This paper addresses the depolarisation effect in off-body body area networks channels, based on measurements performed at 2.45 GHz in an indoor environment. Seven different scenarios, involving both static and dynamic users, were considered, taking a statistical perspective. The analysis of the cross-polarisation discrimination is performed, as well as the analysis of path loss in co- and cross-polarised channels. Results show a strong dependence of the cross-polarisation discrimination and of channel characteristics on the polarisation and propagation condition, i.e. line-of-sight (LoS), non-LoS or quasi-LoS. Distance, varied between 1 and 6 m in the considered scenarios, is observed to have very little impact on the cross-polarisation discrimination. In the considered dynamic scenario, the channel is characterised by lognormal-distributed shadowing and Nakagami-distributed multipath fading. Parameters of the Nakagami distribution have essentially different values in the co- and cross-polarised channels, showing a trend towards Rice in the former and Rayleigh in the latter. Based on results, a model is proposed for a dynamic off-body channel.

Design and Performance Analysis of a Penta-band Spiral Antenna for Vehicular Communications

Developments in automotive industries are increasing to deliver secured and pleasant journey by exchange of information among the vehicles, inside vehicles, between vehicle and with infrastructure utilizing wireless communication networks (WCN). To meet the requirements for various wireless applications, a new printed planar based circularly polarized penta-band spiral antenna with tapered feed is designed to cover the navigational frequencies viz., 1.2, 1.5 GHz and WCN frequencies viz., 2.4, 3.3 GHz and Dedicated Short Range Communication frequency 5.8 GHz for vehicular mobile communications. A 3D Electromagnetic (EM) tool is used for design and is validated via field measurements with Radio Frequency (RF) equipment. In order to validate the performance of the designed antenna, Received Signal Strength (RSS) experiments were conducted between two vehicles at 2.4 and 5.8 GHz in an open area and on road with a vehicle moving speed of 15 km/h. Further, path loss analysis is done for vehicular environments with line of sight condition are simulated using EM propagation tool and simulated results are compared with empirical model viz., ITU, Two-ray reflection, dual-slope model and COST 231 Walfisch Ikegami model.

A Radio Frequency Identification Technology- Based Positioning and Interference Suppression System for Library Books

Large scale path loss modeling plays a fundamental role in designing both fixed and mobile radio systems. Wireless system are complex systems, so that prediction of the radio coverage is not done in an exact manner. Therefore before setting the system we need to choose a proper model of predicting path loss and interference. These proper methods depend upon the system environment, desired radio coverage and system frequency. In this paper of predicting path loss and interference analysis of UHF-RFID, we try to eliminate the problems associated of positioning and interference suppression system of library books to RFID systems. Simulation results show that the proposed method can thus improve overall system performance substantially.

Chirality effects on channel modeling for THz-band wireless communications in LoS/NLoS propagation

Channel modeling in the Terahertz frequency band has become a very hot research field, above all in the context of nano-Internet of Things. Thanks to the exploitation of frequencies in the interval ranging from 0.06 to 10 THz, it is envisioned the possibility to overcome the issues related to the spectrum scarcity and capacity limitation. On the other hand, the design of new channel models, able to capture the inherent features of the phenomena related with this specific field is of paramount importance. Very high molecular absorption, and very high reflection loss are peculiarities phenomena that need to be included in these models. In this paper, we present a full-wave propagation model of the electromagnetic field that propagates in the THz band both for Line-of-Sight and Non-Line-of-Sight propagation models. In the full-wave model, we also introduce the chirality effects occurring in the propagation medium, i.e., a chiral metamaterial. Finally, the analysis of path loss in Line-of-Sight and Non-Line-of-Sight propagation models, and for biological and indoor application scenarios, has been carried out through simulation results.

Pathloss Measurements and Prediction using Statistical Models

There is a major expansion in the market of wireless communications services in urban areas. New regulatory environments as well as rivalry in the communications industry necessitate that these systems be arranged quickly and at low cost. Computer-based radio propagation prediction tools are strong candidates for this goal. This paper provides an extension of pathloss analysis in urban environments in Oman. The paper addresses the applicability of Okumura-Hata model in an area in Oman in GSM frequency band. Trigonometric Regression Model is used for data prediction at unknown nodes. These can be used to make desired forecasts. The results are acceptable, can be used primarily for OMAN, and can be extended for other regions.

Analysis of dynamic path loss based on the RSSI model for rupture location analysis in underground wireless sensor networks and its implications for Earthquake Early Warning System (EEWS)

Sensors deployed in underground tunnels found that radio frequency signals suffer significant signal strength attenuation which can result in considerable variation of link quality on the receiving end. This study analyzes the received signal strength index (RSSI) based on the development of a theoretical wireless sensor model for data collection by enabling sensors to determine the location from which each data packet is obtained. To improve positioning accuracy, the complex radio wave propagation environment requires the use of a voronoi cell to minimize signal attenuation. A relatively simple calculation is used to predict the intensity and perception range of the received wireless signals to measure the extent of signal reduction in the attenuating rock medium. Simulation results show that RSSI-based localization and wireless network lifetime and throughput measurements are more accurate when the node concept is applied to the self-locating rupture zones than the maximum likelihood estimation method. The proposed minimum energy relay routing technique based on beacon node chain deployment is found to help correct localization errors resulting from interference caused by the underground tunnel environment. The extent of localization and power of the sensor nodes are determined based on the beacon node chain deployment of tunnel wireless sensor networks. The algorithm accounts for the distance and the corresponding RSSI between adjacent beacon nodes to calculate the actual path loss parameter in the tunnel. The proposed model can serve as the theoretical basis for locating ruptures in underground wireless sensor network nodes, thus maximizing the monitoring range of large scale tectonic environments while minimizing equipment cost. We recommend that this model can be field tested through a series of experiments by researchers and engineers working in seismology, telecommunication, and information technology.