Empirical Path Loss Model Research Articles

Adaptive Empirical Path Loss Prediction Models for Indoor WLAN

This paper presents robust empirical path loss models to characterize indoor propagation for access point (AP) deployed at different heights. The proposed models are developed with wireless local area network infrastructure at 2.4 GHz. The models are backed by extensive received signal strength (RSS) measurements acquired in line of sight and obstructed line of sight regions. The models are developed for two conditions, viz; quasi realistic and realistic RSS measurements. The quasi realistic measurements are taken after suppressing human intervention and electrical interferences to minimum. While the realistic RSS measurements are made in presence of all the human interventions and electrical interferences. The shadow fading component for both quasi realistic and realistic conditions is statistically modeled with the dependency on AP height. The proposed technique can be applied with higher confidence level to the buildings with similar construction features where RSS measurements are made upon. The results reveal that the performance of the proposed propagation models is significantly higher than the existing International Telecommunication Union-path loss model. The results also demonstrate that the realistic path loss model is more robust than the quasi realistic model.

RADIO PROPAGATION CHARACTERISTICS OF INDOOR LOCATION SYSTEM BASED ON RSSI AT 490 MHz

Localization and tracking technology based on received signal strength indicator (RSSI) is one of the most popular topics because of its low demand on hardware and cost. But the complexity of the indoor environment, leads to the uncertainty of the radio propagation which can seriously affect the positioning accuracy based on the received signal strength. Focused on the wall reflection in the indoor environment, the radio propagation characteristic based on ray-tracing model is analyzed and one strategy for the near wall localization is presented. The actual hardware platform and experimental test results show the applicability of the empirical logarithmic path loss model for localization and the effect of the wall reflection.

Decentralised malicious node detection in WSN

The sensitive role that wireless sensor networks (WSNs) play in interpreting the environment characteristics and the need for ensuring the integrity of the sensor readings, necessitate the use of security mechanisms. One of the main security issues in WSNs is manifested when malicious nodes spoof their identities and locations. In this paper, we propose a decentralised malicious node detection technique based on the received signal strength indicator (RSSI). The method is probabilistic, taking into account shadowing and fading effects. An empirical pathloss model is generated at each node during a discovery phase. This method takes into consideration mobility, channel conditions, and network density among other factors. In addition, the developed technique is able to localise the detected node within a small area. Simulation results highlight the high detection rate of the method under varying conditions.

Adjustment of Cost 231 Hata Path Model For Cellular Transmission in Rivers State

Path loss prediction models are essential tools in radio network planning for cellular transmission as they are used for received signal strength estimation, link budget design and analysis, cell size estimation, and interference optimization. This paper presents empirical path loss models developed for WCDMA microcells operating at 2100MHz on live radio Globacom Node Bs in the urban, suburban, and rural areas in Rivers state. The performance of COST 231 Hata model, Stanford University Interim, and Electronic Communication committee 33 were compared with measured field data. COST 231 Hata model gave a better prediction but with high RMSE and SD which are outside the acceptable value for a good radio signal propagation. COST 231 Hata model was for adjustment based on Linear Least Square Algorithm (LLSA). After adjustment and simulations, the adjusted COST 231 Hata model gave better predictions with minimum MSE and SD that are within the acceptable values. The adjusted COST 231 Hata can accurately be used for predicting the radio characteristic of Rivers State.

Empirical Path Loss Models for C-Band Airport Surface Communications

AeroMACS is a system currently under development for airport surface communications. It is based on the IEEE802.16-2009 standard, and is developed in cooperation with the WiMAX forum. The frequency band allocated to AeroMACS is 5091-5150 MHz. When specifying the AeroMACS system, knowledge of typical propagation conditions at airports is of importance. Typically, path loss models are used to estimate the range of a transmitter within different zones of the airport, and typically fading characteristics are used to estimate the performance of, e.g., the selected coding and modulation schemes. Propagation measurements have been performed at the Barajas airport in Madrid, Spain. The measurements includes Non-Line-Of-Sight (NLOS) as well as Line-Of-Sight (LOS) conditions. Based on these measurements, path loss parameters and path loss models are developed for different zones of large airports.

Planning of WiMAX Networks Based on Modified Empirical Path Loss Model

Abstract The prosperity and demand of wireless access technology have drawn tremendous attention from researchers for the Worldwide Interoperability for Microwave Access (WiMAX) over the past decade. This paper presents developed and adapted empirical path loss model (Samir Model) for the planning of WiMAX networks. The empirical propagation path loss models have a significant influence in wireless communication systems design. Predicting and finding the path loss are essential in planning and designing WiMAX networks. Three empirical models, the Stanford University Interim (SUI) model, the COST-231 Hata model and Samir model have been investigated in this work. Reference path loss of 3.5GHz WiMAX networks data is compared with the above mentioned models to demonstrate the responses of WiMAX systems based Samir empirical path loss model and confirm it is more comprehensive to combine both SUI and COST-231 Hata models . Many dependent parameters of the WiMAX planning problems are tested in different types of topography (rural, urban and suburban) such as path loss, base station and receiver antenna height, shadow fading, transmitting power and receiver sensitivity against distance between transmitter and receiver.

Path Loss through Pine Forest around Beach for Wireless Sea Wave Energy Sensor Network

This paper presents an empirical path loss model through forest for measuring sea wave energy using 2.4 GHz wireless sensor network (WSN). The empirical path loss model was determined from measurement campaign by using 18 dBm transmitter and the receivers with a low noise amplify. The conventional path loss models for forest environments were carried out such as Weissberger, ITU-R, COST 235 and Torrico models. From the results it is found that the proposed model provides a good agreement and is used for planning WSN.

Intra-, Inter-, and Extra-Container Path Loss for Shipping Container Monitoring Systems

This letter presents empirical path loss models for an environment of stacked shipping containers. Specifically, a system for wireless monitoring of containers is considered for which three different types of wireless links are identified, namely intra-, inter-, and extra-container links. Furthermore, the inter-container link is investigated for the two most common types of container stacking: row and block stacking. Intra- and inter-container path loss are investigated at IEEE 802.15.4 frequencies of 433, 868, and 2400 MHz. Extra-container path loss is examined at GSM/UMTS frequencies of 900, 1850, and 2100 MHz. Distance-dependent path loss models are proposed for the inter- and extra-container links (high-correlation coefficients between 0.76 and 0.86). The resulting path loss models can be used in link budget calculations for container monitoring systems.

An Empirical Path-Loss Model for Wireless Channels in Indoor Short-Range Office Environment

A novel empirical path-loss model for wireless indoor short-range office environment at 4.3–7.3 GHz band is presented. The model is developed based on the experimental datum sampled in 30 office rooms in both line of sight (LOS) and non-LOS (NLOS) scenarios. The model is characterized as the path loss to distance with a Gaussian random variableXdue to the shadow fading by using linear regression. The path-loss exponentnis fitted by the frequency using power function and modeled as a frequency-dependent Gaussian variable as the standard deviationσofX. The presented works should be available for the research of wireless channel characteristics under universal indoor short-distance environments in the Internet of Things (IOT).

An Empirical Path Loss Model and Fading Analysis for High-Speed Railway Viaduct Scenarios

Based on the narrowband 930-MHz measurements taken along the “Zhengzhou-Xi'an” high-speed railway in China, an empirical path loss model is proposed. It is applicable to high-speed railway viaduct scenarios, considering the influences of viaduct height H and base station antenna relative height h, which are not well-covered by existing large-scale models. The path loss exponents are investigated, based on which the influence of viaduct on propagation is discussed. The fading depth up to 15.96 dB and the Ricean K -factor with mean value of 3.79 dB are obtained.

Predicting coverage in wireless local area networks with obstacles using kriging and neural networks

In this paper, a new approach based on ordinary kriging is proposed to predict network coverage in wireless local area networks. The proposed approach aims to reduce the cost of active site surveys by estimating path loss at points where no measurement data is available using samples taken at other points. To include the effect of obstacles on the covariance among points, a distance measure is developed based on an empirical path loss model. The proposed approach is tested in a simulated wireless local area network. The results show that ordinary kriging is able to estimate path loss with acceptable error levels.

Comparative Analysis of Different Parameters in Propagation Model for Mobile Communication System

Nowadays the wireless technology becomes popular and receives growing acceptance as a Broadband Wireless Access (BWA) system. Wireless system has potential success in its line-of-sight (LOS) and non line-of-sight (NLOS) conditions which operating with different frequency. Estimation of path loss is very important in initial deployment of wireless network and cell planning. Numerous path loss (PL) models (e.g. Okumura Model, Hata Model) are available to predict the propagation loss, but they are inclined to be limited to the lower frequency bands. Radio propagation is essential for emerging technologies with appropriate design deployment and management strategies for any wireless network. It is site specific and can vary significantly depending on terrain, frequency of operation, velocity of mobile terminal, interface sources and other dynamic factor. Accurate characterization of radio channel through key parameters and a mathematical model is important for predicting signal coverage, achievable data rates, specific performance attributes of alternative signaling and reception schemes. Empirical path loss models for macro cells such as free path loss, Hata Okumura, COST 231 Hata and ECC 33 models are analyzed and compared. The received signal strength is calculated with respect to distance to determine the model that can be adopted to minimize the number of handoffs and avoid ping pong effect. This paper proposes a comparison study of different propagation model such as Okumara-Hata model, COST 231 Hata model, ECC-33 to calculate path loss for highway and urban between Bhubaneswar and Cuttack. Comparative study with real time measurement obtained from Bharat Sanchar Nigam Limited (BSNL) a GSM based wireless networks for Bhubaneswar and Cuttack has been implemented. A suitable empirical model for different environments is to be proposed. Also calculate received signal strength for each environment under all three models and calculate the probability for each case. Keywords: Cellular mobile, Handoff, Path loss, Ping Pong, Received signal strength.

Performance of short-range non-line-of-sight LED-based ultraviolet communication receivers

Utilizing an empirical path loss model proposed in the first paper of a two-part series, the bit error rate performance of short-range non-line-of-sight ultraviolet communication receivers is analyzed. Typical photodetector models and modulation formats are considered. Our results provide semi-analytical prediction of the achievable communication performance as a function of system and channel parameters, and serve as a basis for system design.

Received signal strength based mobile terminal positioning error analysis and optimization

The current paper considers the problem of Received Signal Strength (RSS) based Mobile Terminal (MT) positioning in cellular mobile networks like GSM and provides a set of MT–Base Station (BS) distance statistical estimators which improve positioning accuracy. The impact of both MT–BS distance estimation error (based on typical empirical path-loss models, i.e., Hata, Cost231) and trilateration to the MT position estimation accuracy is analyzed. The proposed set of MT–BS distance estimators improves the positioning accuracy by a factor of up to ∼50% according to an ideal simulation model. However, even with this improvement, RSS based positioning still provides accuracy similar to plain Cell Global Identity (CGI) technique. The paper then considers techniques which rely on a time-series of RSS measurements (i.e., Statistical Terminal Assisted Mobile Positioning (STAMP) [1] and MT tracking [2]) indicating that the proposed estimators can improve their performance too. To obtain a realistic picture, GSM field measurements are also analyzed indicating that the proposed estimators indeed deliver MT positioning accuracy improvement however, at a lower degree vs. the one theoretically expected.

Indoor channel characteristics based on wideband MIMO measurements at 5.25 GHz

Extensive indoor channel measurements were conducted in Beijing with wideband multiple-input multiple-output (MIMO) sounder at 5.25 GHz. Both line-of-sight (LOS) and non-line-of-sight (NLOS) propagation were measured in the indoor office and hotspot scenarios. On the basis of measured data, statistical channel characteristics are presented in this article, including the empirical path loss (PL) models, three excess delay parameters, circular azimuth spread (CAS), and circular elevation spread (CES). Comparative analysis of different propagation mechanisms in two scenarios is conducted. These values are significant for indoor coverage and technical research of MIMO and orthogonal frequency division multiplexing (OFDM) for the international mobile telecommunications-advanced (IMT-Advanced) system.

Large-Scale Characteristics of 5.25 GHz Based on Wideband MIMO Channel Measurements

Based on the channel measurements at 5.25 GHz in the hotspot area, empirical path loss (PL) models are developed and discussed for the IMT-Advanced system design. The measured scenarios include indoor line-of-sight (LOS), non-LOS, outdoor LOS/obstructed LOS, and outdoor-to-indoor propagations. The PL exponent, intercept, and standard deviation of shadow fading are obtained by using the least square method in each scenario. Moreover, the floor attenuation factor and penetration loss are determined from the cross-floor measurement and outdoor-to-indoor measurement, respectively.

A robust prediction model using ANFIS based on recent TETRA outdoor RF measurements conducted in Riyadh city – Saudi Arabia

Received wireless signal prediction is a difficult and complex task. Various types of prediction models such as deterministic, empirical, as well as statistic were developed. However, they rarely adapt well to different types of environments. Prediction models based on artificial intelligence techniques are the recent alternative approaches to predict the signal strength at a particular location in an investigated area. The advantage of using artificial intelligence for field strength prediction is given by the flexibility to adapt to different environments, high-speed processing, and the ability to process a high quantity of data. In this paper, adaptive neuro-fuzzy inference system (ANFIS) is used as a robust wireless signal predictor. The performance of the proposed predictor is then compared to the predictors based on radial basis function neural network (RBF-NN), and three most widely used empirical path loss models. The performance criterion selected for the comparison between the actual and the predicted data are the root mean square error (RMSE), maximum relative error (MRE), and goodness of fit ( R 2 ). It turns out that the ANFIS prediction model outperforms the predictors based on empirical models, and is marginally better than RBF-NN predictor.

Empirical pathloss model for indoor geolocation using UWB measurements

A novel empirical approach is presented for modelling the path loss behaviour of the direct path (DP) between the transmitter and receiver, which is important for time-of-arrival-based indoor geolocation coverage characterisation. Using ultra wideband (UWB) measurements in four sites and three ranging scenarios, pathloss models at 500 MHz and 3 GHz system bandwidths are provided, centred on 4.5 GHz for DP and total signal power. In addition, ranging coverage analysis is provided using the DP models.

Path loss model for wireless narrowband communication above flat phantom

A new empirical path loss model for wireless communication at 2.4 GHz above a flat, lossy medium, representing human tissue, is presented. The model is valid for dipole antennas for heights up to 5 cm above the phantom and for distances up to 40 cm, and was applied to muscle and brain simulating media. For antennas placed close to the lossy medium, it was found that antenna height has a major influence on path loss. The model has been validated by measurements and simulations, which show excellent agreement.

Path-Loss Models for Urban Microcells at 5.3 GHz

Based on wideband 5.3 GHz measurements performed in downtown Helsinki, Finland, empirical path-loss models for regular urban street grids were developed for future beyond 3G (B3G) wireless radio systems.