Okumura Hata Research Articles

A 3D simulation framework with ray-tracing propagation for LoRaWAN communication

The adoption of Low-Power Wide-Area Networks (LP-WAN) for interconnecting remote wireless sensors has become a reality in smart scenarios, covering communications needs of large Internet of Things (IoT) deployments. The correct operation and expected performance of such network scenarios, which can range hundreds or thousands of nodes and tens of squared kilometres, should be assessed before carrying out the deployment to save installation and maintenance costs. Common network planning tools can help to roughly study potential coverage, but network simulation offers fine-grained information about network performance. Nevertheless, current simulation frameworks include limited propagation models based on statistical and empirical measurements that do not consider scenario particularities, such as terrain elevation, buildings or vegetation. This is critical in urban settings. In this line, this paper presents a simulation framework including a network simulator, a 3D engine and a ray-tracing tool, which models realistically the performance of Long-Range Wide-Area Network (LoRaWAN) communication technology. We have evaluated the performance of the solution taking as reference experimental campaigns in the city of Cartagena (Spain), comparing data obtained when simulating with the commonly employed propagation models such as Okumura–Hata or path loss. Results indicate that our framework, set-up with data from open geographical information systems, accurately fits experimental values, reporting improvements between 10% and 50% in the error committed when estimating signal strength in challenging urban streets with signal obstruction, as compared with the better performing classical model, Okumura–Hata.

Performance analysis for a suitable propagation model in outdoor with 2.5 GHz band

As demand for mobile wireless network services continues to rise, network planning and optimization significantly affect development. One of the critical elements in network planning is predicting pathloss. Thus, propagation models predict pathloss in indoor and outdoor environments. Choosing the appropriate propagation model for the area out of existing models is essential for network planning. Selected propagation models suitable with 2.5GHz, such as Friis Free Space Propagation Model (FSPL), Sandford University Interim (SUI), Ericsson, Okumura, and COST-231 HATA models, are utilized for evaluation and compared with empirical data collected from long-term evolution (LTE) networks in urban areas. The best acceptable model is chosen based on statistical results such as mean, standard deviation, and root mean square errors (RMSE). The analytical results show Cost-231 Hata model fits the empirical pathloss with a minimum RMSE of 5.27 dB.

Comparison of radio propagation models in five LTE coverage cells in Riobamba

This article makes a comparative analysis of the power intensity levels measured with the Network Cell Info Lite application and the performance of the different Log-Normal, Okumura Hata, COST 231, Wolfish Bertoni and SUI propagation models in the Frequency Band 4G LTE. The study was carried out in 5 LTE coverage cells located in the southern area of ​​the City of Riobamba and the model that best fits each cell is limited using absolute error analysis, obtaining an empirical correction factor for the proposed models. For the analysis of the absolute error, 3 measurement campaigns were carried out with 50 samples where the mean value was obtained. The analysis carried out will be suspended because the Log-Normal model is the one that best fits the Riobamba environment considering that it is a residential area, and that the power levels vary from (-80 dBm to -106 dBm) and that the coverage areas were determined up to 200m.

Okumura Hata Propagation Model Optimization in 400 MHz Band Based on Differential Evolution Algorithm: Application to the City of Bertoua

Propagation models are the foundation for radio planning in mobile networks. They are widely used during feasibility studies and initial network deployment, or during network extensions, particularly in new cities. They can be used to calculate the power of the signal received by a mobile terminal, evaluate the coverage radius, and calculate the number of cells required to cover a given area. This paper takes into account the standard k factors model and then uses the differential evolution algorithm to set up a propagation model adapted to the physical environment of the Cameroonian cities of Bertoua. Drive tests were made on the LTE TDD network in the city of Bertoua. Differential evolution algorithm is used as the optimization algorithm to deduct a propagation model which fits the environment of the considered town. The calculation of the root mean square error between the actual data from the drive tests and the prediction data from the implemented model allows the validation of the obtained results. A comparative study made between the RMSE value obtained by the new model and those obtained by the Okumura Hata and free space models, allowed us to conclude that the new model obtained is better and more representative of our local environment than the Okumura Hata currently used. The implementation shows that Differential evolution can perform well and solve this kind of optimization problem; the newly obtained models can be used for radio planning in the city of Bertoua in Cameroon.

Comparison of radio propagation models in five LTE coverage cells in Riobamba

This article performs a comparative analysis of the power intensity levels measured with the Network Cell Info Lite application and the performance of the different propagation models: Log-Normal, Okumura Hata, COST 231, Walfish Bertoni, and SUI in the 4G LTE Frequency Band. The study was conducted in five LTE coverage cells located in the southern area of the city of Riobamba. The model that best fits each cell was chosen by means of absolute error analysis, thus obtaining an empirical correction factor for the proposed models. For the analysis of the absolute error, three measurement campaigns were carried out with 50 samples where the mean value was obtained. After applying the aforementioned models, the Log-Normal model yielded the most favorable results, being the one that achieved the best adaptation in Riobamba, since the power levels vary in the range (-80; -106) dBm at a coverage area not exceeding 200m.

Designing and Implementing a Microstrip Antenna on LoRa Frequency for Smart Meter Communication

The long-range wide area network (LoRaWAN) has been widely used for sensor networks, including smart meter (SM). The SM can report power consumption to the control center automatically via a communication link. An antenna is a key component to indicate an effective communication system. The microstrip antenna (MSA) works based on the unidirectional radiation pattern. The advantages of MSA are its light weight, small size, and ability to be easily etched on a print circuit board. These advantages are needed for the SM communication because SMs are installed on electric poles that have limited space. In this pa- per, we implement the MSA for SM communication on LoRaWAN technology that operates at a frequency of 920–925 MHz in Thailand. The proposed MSA is used to design a new path loss model for LoRaWAN in urban areas. Results show that our MSA is effectively close to commercial antennas in a 2.2 km range, with the packet delivery ratio reaching 52.93%. We analyze the results by using a mathematical equation that includes the free space model, the Okumura–Hata model, root mean squared error, and coefficient of determination.

A New-Dynamic Adaptive Data Rate Algorithm of LoRaWAN in Harsh Environment

The adaptive data rate (ADR) algorithm is used in LoRaWAN, allocating an appropriate transmission rate for terminal equipment to improve channel utilization and reduce power consumption. However, the standard ADR algorithm is only suitable for static terminal equipment. In addition, due to the complexity of the external environment, the selected data rate will not match the new environment and communication packets will be lost. Therefore, this article proposed a novel and more effective ADR algorithm called new-dynamic ADR (ND-ADR). The algorithm mainly solves two problems, i.e., the standard ADR algorithm cannot be applied to mobile terminal devices and the poor communication quality and high packet loss rate in harsh environments. In this study, we also developed a frame for LoRaWAN (FLoRaWAN), a simulation framework for the star network topology LoRaWAN in OPNET. Furthermore, we built an OKUMURA–HATA model and additionally introduced a noise factor <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta$ </tex-math></inline-formula> to simulate the loss of wireless communication in harsh environments. Finally, extensive simulation results showed that the number of data packets required by different end nodes for rate allocation was different. Compared with the standard ADR algorithm, even for mobile nodes in harsh environments, the ND-ADR algorithm reduced network energy consumption by about 13%, reduced network delay by about 18%, and increased effective throughput by about 15%. Therefore, the improved ND-ADR algorithm is more suitable for wireless communication of removable nodes in harsh environments. Its advantages are better awareness of link environment, faster data rate regulation, improved channel utilization, and further reduction of network energy consumption.

A Radio Propagation Model for a Rainforest–River Environment Using UTD and Geometrical Optics

This paper describes a radio propagation model for a mixed environment formed by rainforest and river in Brazil's Amazon region. The model uses Geometrical Optics and the Uniform Theory of Diffraction for the calculation of the electric field at the receiver, accounting for the different transmitted, reflected and diffracted components in each of the environments. Simulation results are compared with measurements performed in Belem (Para) at 521 MHz, showing a good fit, with an average Root Mean Square Error (RMSE) over all measured paths of 3.3 dB and a maximum one of 4.2 dB. The proposed model performs much better than the ITU-R P. 1546 and the Okumura Hata ones, where the comparison with measurements leads to an RMSE higher than 8 dB. In addition, by using Genetic Algorithms, the electrical parameters for the dense forest are obtained, enabling to slightly decrease (0.14 dB on the average of all measured paths) the RMSE of the proposed model.

Propagation Measurements and Pertinency of Models for Communications Systems in Oman

This article discusses the usefulness of Okumura-Hata model and Sakagami model in urban areas for 2G and 3G communication systems. At some places, applicability of the models (Okumura Hata and Extended Sakagami) is studied and extended to a much lower distance from the tower than the specified minimum distance indicated in the model. Authors did an extensive drive test in urban areas and post also processed data and proposed theoretical modified model which is presented and compared for different data sets at different locations in Oman. Higher order interpolating polynomial was also used which helps in reasonable prediction for RF engineers.

Investigation of path loss and modeling for digital terrestrial television over Nigeria

Accurate prediction of path losses is a key factor in Digital Terrestrial Television (DTTV) to ensure Quality of Service (QoS). This study investigates the path losses of three Digital Terrestrial Television Base Stations (DTTBS) in Lagos, Kaduna and Katsina cities of Nigeria. The Received Signal Strength (RSS) of the DTTBS was measured at intervals along selected routes around the stations using a digital signal strength meter. So also, the transmitter-receiver distances of data points with their corresponding geographic coordinates and heights were measured using a hand held GPS receiver. Also measured concurrently were some of the location's - based surface meteorological parameters such as temperature, atmospheric pressure and humidity, using a compact wireless weather station. In addition, the corresponding surface radio refractivity values along the routes were computed using the meteorological parameters recorded. Data were collected during dry and wet season months' covering a period of three years. Path losses were calculated using Okumura-Hata model. Results for all the routes and seasons revealed that path loss increases with increase in trans-receiver distances, however path losses were higher during wet compared to dry season's month. Path losses estimated were highest in Kaduna followed by Ikorodu-Lagos and least in Katsina. Average high positive correlation coefficients of 0.76, 0.75 and 0.74 were obtained between path losses and line of sight for Lagos (Coastal zone), Kaduna (Sudan Savannah) and Katsina (Sahel Savannah) respectively. In the same order, negative correlation coefficients of -0.72, -0.79 and -0.63 were obtained between path losses and RSS. In addition, Modified Okumura Hata Model(s) (MOHPL) that incorporates the effect of the specified tropospheric parameters were proposed. Results also revealed that path losses obtained by Okumura-Hata model increase with increase in LOS separation distance from the base station following a consistent exponential rise while the Modified Okumura-Hata Model (MOHPL) followed similar trend with few exceptions of crests and troughs depicting the influence of the incorporated location's-based tropospheric parameters. Another finding is that Okumura Hata model under estimated the path losses associated with digital terrestrial television channel over the study locations. In order to ensure high reliability of power budgets and link's design, the proposed models are recommended for use over the study locations. The overall findings of this work will be useful for the accurate prediction of path losses and the design of power budgets and links over digital terrestrial television and similar wireless channels on the UHF band.

ANALISIS MODEL PROPAGASI KOMUNIKASI BERGERAK PADA SISTEM GSM DI PT. XL AXITA PADANG

This research based by the weak received signal received by the Mobile Station (MS) caused loss propagation trajecktory which allows the impending failure of calls and data connections. The purpose of this research is todiscover the impairment power received by MS. Monitored from the value of Rx Level and knowing the propagation model of Padang city urban areas in general.The method of measurement used is a Test Drive using TEMS Investigations software version 8.0. then analyzed with empirical models and models Okumura Hata, the results of the analysis compared with the standard value of Rx Level. This research was conducted in the morning and evening for five days.The analysis showed: (1) The signal quality measurements on base stations Terandam in average -81.6 dBm, and Hata model calculations on average -79.66 dBm, Okumura models average of -78.47 dBm, then the signal quality in good condition, BTS Simpang Haru is an average measurement of -82.7 dBm, and Hata model calculations on average -86.49 dBm, Okumura models average of -81.43 dBm, then the signal quality in good condition and the BTS Cendana Andalas in average measurement -80.03 dBm, and Hata model calculations on average -90.05 dBm, Okumura models average of -86.19 dBm, then the signal quality in a state of being. (2) Empirically propagation model for urban areas is a desert city in BTS Terandam Hata models, while BTS Simpang Haru and Sandalwood Andalas is a model Okumura. (3) Creep waves are blocked and then undergo reflection resulting trajectory taken further and further away, the received signal varies causing fluctuations in the signal and trigger fading, and failure in call and data. Keywords: MS, Rx Level, Drive Test, TEMS Investigation, transmitter, receiver and diffraction

Contribution to The Performance of Mobile Radio Systems by Optimizing The Okumura Hata Model by Linear Regression: Application to The City of Annaba in Algeria

Contribution to The Performance of Mobile Radio Systems by Optimizing The Okumura Hata Model by Linear Regression: Application to The City of Annaba in Algeria

Outdoor Path Loss Predictions Based on Extreme Learning Machine

In a typical outdoor environment, the propagation of radio waves is usually random in nature, to the extent that the characterization of the wireless channel often becomes very difficult. Several models have been developed to predict the average Received Signal Strength (RSS) for specified distance ranges. However, the use of deterministic models requires high computational efficiency while the prediction results of empirical models may not be as accurate as required. On machine learning approach, the performances of multi-layered feed-forward network models are limited by slow convergence and local minimum, such that a global optimal solution is not guaranteed. In this paper, Extreme Learning Machine (ELM) algorithm is considered in the development of an optimal path loss prediction model for outdoor propagation scenario. Single Hidden Layer Feed-forward Neural Networks (SHLFNNs) are trained and tested with the path loss data that were computed based on the RSS data of a commercial 1800 MHz base station located along Lagos-Badagry highway in Nigeria. The training speed, learning effectiveness, and the generalization ability of Artificial Neural Network Back-Propagation (ANN-BP) and ELM algorithms are analysed. Experimental results show that ELM models are 140 times faster to train than the ANN-BP models. On prediction accuracy, the outputs of ELM, ANN-BP, Okumura–Hata, and COST-231 models have Root Mean Squared Error (RMSE) values of 2.896, 2.449, 7.456, and 6.116 dB respectively; and regression coefficient (R) values of 0.959, 0.973, 0.935, and 0.935 respectively, when compared to the target variable of the training dataset. When the models were tested with new input data that were excluded from the training process, RMSE values of 4.250, 6.622, 8.732, and 7.087 respectively; and R values of 0.893, 0.876, 0.904, and 0.904 respectively are obtained. In conclusion, the findings of this study confirm that ELM algorithm guarantees an optimal path loss model with fast training convergence, high prediction accuracy, and good generalization ability for radio network planning and optimization in outdoor environments.

A Hybrid Path Loss Prediction Model based on Artificial Neural Networks using Empirical Models for LTE And LTE-A at 800 MHz and 2600 MHz

This article presents the development and analysis of a hybrid, error correction-based, neural network to predict the path loss for suburban areas at 800 MHz and 2600 MHz, obtained by combining empirical propagation models, ECC-33, Ericsson 9999, Okumura Hata, and 3GPP's TR 36.942, with a backpropagation Artificial Neural Network (ANN). The network performance was tested along with two optimization techniques - Genetic Algorithm (GA) and Least Mean Square (LMS). Results were compared with data obtained by measurements performed in the vicinity of the Federal University of Rio Grande do Norte (UFRN), in the city of Natal, Brazil. In the end, the hybrid neural network presented the best results, indicating greater similarity with experimental data. The results developed in this research will help to achieve better signal estimation, reducing errors in planning and implementation of LTE and LTE-A systems.

Spectrum Forecast Using Propagation Losses of the Okumura-Hata Model

Radioelectric spectrum occupancy forecast has proven to be useful in the design of wireless systems because of its ability to harness spectrum opportunities like Cognitive Radio (CR). This paper proposes the development of a model that identifies the spectrum opportunities in the channel of a mobile cellular network for an urban environment using the received signal power forecast. The proposed model integrates the Okumura-Hata (O-H) large-scale propagation model with a wavelet neural model. The model results, obtained through simulations, show that the wavelet neural model forecasts with a high degree of precision and that the CR user may forecast the power level that will be received from the primary Base Station (BS) at different distances, which is consistent with the observed behavior in experiments carried out in wireless systems of this type. Finally, the duty cycle is also presented.

New Propagation Model Optimization Approach based on Particles Swarm Optimization Algorithm

ABSTRACT Propagation models are keys components of coverage planning. With the deployment of 4G network worldwide, operators need to plan the coverage of their network efficiently, in order to minimize cost and improve the quality of service. In this paper, the standard model K factors validation of the results and comments will be provided in is taken into account to develop a method for tuning propagation models based on particle swarm optimization algorithm. The data are collected on the existing CDMA2000 1X-EVDO rev B network in the town of Yaounde, capital of Cameroon. The root mean squared error (RMSE) between actual measurements and radio data obtained from the prediction model developed is used to test and validate the technique. The values of the RMSE obtained by the new model and those obtained by the standard model of OKUMURA HATA in urban area are also compared. Through the comparison of RMSE from optimized model and OKUMURA HATA, it can be concluded that the new model developed using particle swarm optimization performs better than the OKUMURA HATA model and is more accurate. The new model is also more representative of the local environment and also similar to the optimized model obtained when using linear regression method. This method can be applied anywhere to optimize existing propagation model.

Adaptive Threshold and Hysteresis for Handoff Initiation in Next Generation Networks from Path Loss Model

Mobility management is evolving as the most astounding area of research for the upcoming researchers. Many issues such as signalling overhead, latency, low bandwidth, low reliability, etc., existed in traditional mobility schemes in wireless networks. But the next-generation heterogeneous networks have resolved many issues and researchers are looking forward to take best use of upcoming generations to provide constant connectivity. In this paper, a fuzzy logic-based adaptive threshold and adaptive hysteresis handoff initialisation algorithm is proposed. It uses data rate, received signal strength indicator and SINR to determine the value of threshold and hysteresis. This algorithm makes use of Okumura Hata Path loss model to determine the value of RSSI, which is then given to fuzzy inference engine. It has been shown that threshold and hysteresis are not only dependent on RSSI but also on many other parameters such as on transmitter height, receiver height and antenna gain, frequency and cable loss.

On the Use of Okumura–Hata Propagation Model on Railway Communications

Although Okumura-Hata prediction model has been a widely used model to estimate radio network coverage, its application in railways environment requires validation and additional studies. This paper presents the main results on a study based on measurements campaigns, and identifies significant differences in parameters that characterize the radio propagation in railways environment, for the 900 MHz band. Both the propagation slope and standard deviation measured values are presented in this work. For validation, the developed model setup was used in the radio planning process, setting a live GSM-R pilot network, operating in Portugal.

The Comparison of Propagation Model for Terrestrial Trunked Radio (TETRA)

A system of digital radio Terrestrial Trunked Radio (TETRA) is designed for communication which need specialility, better privacy, better quality of audio with speed transmission data and access capacity to the internet and telephone network. TETRA system of TMO and DMO operation mode which has wide coverage and reliable than the interference so that the TETRA planning needs a propagation model which corresponding with environment. Therefore, this research compare a pathloss value of calculation of propagation model such as Free Space Loss, Wickson, Bacon, CEPT SE21, Ericsson (9999), ITU-R SM 2028 and Okumura Hata based on the environment are clutter urban, sub urban dan rural. The calculation of pathloss provide that Bacon propagation model is an corresponding model for DMO operation mode with a frequency of 380 MHz, height handhelds 1.5 m and 2 m with pathloss value of 76.82 dB at a distance of 100 m and 113.63 dB at a distance of 1 km while the 400 MHz frequency pathloss value of 77.08 dB at a distance of 100 m and 113.6 dB at a distance of 1 km. The propagation model which corresponding to the TMO operation mode with a frequency of 400 MHz distance of 1 km, the transmitter antenna height (hb) 30 m and receiver antenna height (hm) 1.5 m is a model of Ericsson (9999) on urban clutter with pathloss value of 96.4 dB, the model ITU-R SM2028 in suburban clutter with a pathloss value of 101.13 dB, and the model ITU-R SM2028 on rural clutter with pathloss value of 83.59 dB.Keywords: TETRA, propagation model, urban, suburban, rural

Propagation Models for GSM 900 and 1800 MHz for Port Harcourt and Enugu, Nigeria

For the cellular networks to effectively cover a terrain or environment, accurate prediction of the coverage of the radio frequency signal is highly needed. Wave propagation models are essential and very important tools for determining the wave propagation characteristics for a particular environment. Path loss predictions are therefore required for the coverage planning, determination of multipath effects as well as interference and cell calculations. These calculations lead to high level network planning. Drive test measurements were taken along certain routes in Port Harcourt and Enugu, cities in Nigeria. These measurements were compared with calculated values from Okumura- Hata and COST231 Hata models. The average path loss values for the routes ranged from 135.01 db to 138.48 dB at 900 MHz, 142.26 db to 147.30 db at 1800 MHz. The standard deviations varied from 2.71 db to 15.94 db for the Okumura Hata model at 900 MHz whereas for the COST231 Hata model it was from 1.91 db to 15.04 db. Similarly, the mean square errors (µe) ranged from 0.8 db to 5.04 db for Okumura Hata at 900 MHz. For COST 231 Hata at this frequency, it was from 0.6 db to 4.76 db. This agrees with the acceptable International range. The acceptable range lies between 1? µ ? 15 db (Wu & Yuan 1998). The mean square error at 1800 MHz varied from 0.11 db to 5.40 db.