Propagation Modeling

The study here compares and evaluates the performance of different antennas such as the dipole, Yagi-Uda, and helical antennas in the context of FM broadcasting. The main goal here is to compare how these antennas perform in terms of signal strength and efficiency. The study carried out experiments in a controlled environment and tested the antennas in an outdoor environment by scanning the FM band from 88 to 108 MHz. The experiments were conducted in a similar environment to compare the performance of these antennas. The parameters taken for the study were gain in dBi, SNR, RSSI, bandwidth efficiency, and radiation pattern stability. The results obtained from the experiments show that the dipole antenna performed at an average gain of 2.1 dBi and an RSSI of-64 dBm at a distance of 1 km. The study also found that the SNR for the dipole was 18.4 dB. The results obtained from the experiments show that the dipole antenna performed well at a distance of 3 km. The performance of the dipole antenna was average. The study also found that the Yagi-Uda antenna performed very well in terms of directional efficiency. The results obtained from the experiments show that the Yagi-Uda antenna performed at an average gain of 9.6 dBi and an RSSI of-47 dBm at a distance of 1 km. The study also found that the SNR for the Yagi-Uda antenna was 27.8 dB. The results obtained from the experiments show that the Yagi-Uda antenna performed very well at a distance of 8.5 km. The study also found that the helical antenna performed at an average gain of 6.2 dBi and an RSSI of-55 dBm at a distance of 1 km. The study also found that the SNR for the helical antenna was 23.1 dB. The results obtained from the experiments show that the helical antenna performed very well at a distance of 6.2 km. The study found that the helical antenna performed better in an environment with buildings and foliage. The study concluded that the choice of the antenna depends upon the requirements. The study concluded that the Yagi-Uda antenna should be used for long-distance and highgain requirements. The study concluded that the helical antennas should be used for difficult propagation environments. The study concluded that the dipole antennas should be used for economical requirements.

This paper presents a propagation prediction technique to predict propagation mechanisms for fixed terrestrial line-of-sight (LOS) radio links, especially proposed for rural environments. We report the results of a short-term propagation measurement campaign carried out in the area of Ankara, Turkey. The field measurements were performed at the frequency of 2.536 GHz for a period of three months in summer 2015. It is observed that the difference between measurement data and predicted mean received power is smaller than the standard deviation value provided by Recommendation ITU-R P. 1546. Index Terms-fixed terrestrial line-of-sight (LOS) radio link, field measurement, point-to-point communication, propagation modeling. I.

Signal path loss models play significant role in predicting signal strength, its attenuation, and enable characterisation of the radio frequency channel. Distance, transmitting frequency, and obstacles are critical elements that emphasize the signal strength variability affecting signal propagation at various areas. This study employs denoised data and unprocessed data to formulate path loss models using drive-test method. The signal strengths were measured, analyzed, and presented considering four base-stations (BS) within Port Harcourt using Long Term Evolution (LTE) at 2600MHz. A comparative analysis was performed between COST231-Hata model, Okumura-Hata model, and the developed models, based on metrics such as RMSE, MAE, and correlation coefficient (R). The developed model using denoised data exhibited excellent performance with the lowest RMSEs of 2.88dB, 3.94dB, 4.76dB, 6.94dB, demonstrating its accuracy in predicting path loss. Additionally, it yielded the least MAE values of 2.20dB, 2.87dB, 3.48dB, 5.82dB as compared to the existing standard models. The correlation coefficients of the developed model showed close alignment with the measured path loss of 90.04%, 78.61%, 92.21% and 91.23% for the BSs respectively. Validation of the developed models with data from different BSs confirms high efficiency of 97.41%. Conclusively, COST231-Hata and Okumura-Hata models exhibited limited accuracy in predicting path loss within Port Harcourt. The developed model illustrates exceptional performance and it's recommended for effective communication network planning and optimization in the area. Future research is encouraged to expand the study to include more BS, regions, and locations for an in-depth and robust model development.

Signal path loss models play significant role in predicting signal strength, its attenuation, and enable characterisation of the radio frequency channel. Distance, transmitting frequency, and obstacles are critical elements that emphasize the signal strength variability affecting signal propagation at various areas. This study employs denoised data and unprocessed data to formulate path loss models using drive-test method. The signal strengths were measured, analyzed, and presented considering four base-stations (BS) within Port Harcourt using Long Term Evolution (LTE) at 2600MHz. A comparative analysis was performed between COST231-Hata model, Okumura-Hata model, and the developed models, based on metrics such as RMSE, MAE, and correlation coefficient (R). The developed model using denoised data exhibited excellent performance with the lowest RMSEs of 2.88dB, 3.94dB, 4.76dB, 6.94dB, demonstrating its accuracy in predicting path loss. Additionally, it yielded the least MAE values of 2.20dB, 2.87dB, 3.48dB, 5.82dB as compared to the existing standard models. The correlation coefficients of the developed model showed close alignment with the measured path loss of 90.04%, 78.61%, 92.21% and 91.23% for the BSs respectively. Validation of the developed models with data from different BSs confirms high efficiency of 97.41%. Conclusively, COST231-Hata and Okumura-Hata models exhibited limited accuracy in predicting path loss within Port Harcourt. The developed model illustrates exceptional performance and it's recommended for effective communication network planning and optimization in the area. Future research is encouraged to expand the study to include more BS, regions, and locations for an in-depth and robust model development.

Estimates of the noise source spectra of ships based on long term measurements in the Baltic sea are presented. The measurement data were obtained by a hydrophone deployed near a major shipping lane south of the island Öland. Data from over 2,000 close-by passages were recorded during a 3 month period from October to December 2014. For each passage, ship-to-hydrophone transmission loss (TL) spectra were computed by sound propagation modeling using 1. bathymetry data from the Baltic Sea Bathymetry Database (BSBD), 2. sound speed profiles from the HIROMB oceanographic model, 3. seabed parameters obtained by acoustic inversion of data from a calibrated source, and 4. AIS data providing information on each ship's position. These TL spectra were then subtracted from the received noise spectra to estimate the free field source level (SL) spectra for each passage. The SL were compared to predictions by some existing models of noise emission from ships. Input parameters to the models, including e.g., ship length, width, speed, displacement, and engine mass, were obtained from AIS (Automatic Identification System) data and the STEAM database of the Finnish Metereological Institute (FMI).

In this article, tag and reader multi-standards RFID antennas are presented. These antennas are matched on one the UHF RFID regulate frequency band (860-960 MHz) and on the ECC UWB frequency band (6-8.5 GHz). Tag is composed of two antennas, one match for the RFID applications with classical RFID input impedance, one for UWB matched at 50 Ω. Tag sizes are limited to credit card sizes (85x54 mm). Reader antenna is an association of a bowtie and a dipole antenna and it is matched on 50 Ω on twice bands. There is no sizes' specification for reader antennas. The substrate is FR4 0.8 mm thick for tag antennas and 1.6 mm for reader antennas. Epoxy's relative permittivity is 4.4 and its dielectric loss tangent is 0.02. Design rules, simulations, measures and perspectives are exposed.

In this paper, the magnetic field shaping technique using the magnetic field repeater for high frequency radio frequency identification (HF-RFID) system and nearfield communications (NFC) system is proposed. This technique aims to improve the communication area between HF-RFID or NFC reader and passive tag by changing the magnetic field distribution over the original HF-RFID or NFC reader antenna. The multiple rectangular loop resonators cooperating with low loss air variable capacitors are employed to construct the proposed magnetic field repeater. The proposed magnetic field repeater is installed on top of the original HF reader antenna without any direct connection to the original reader antenna. The HF-RFID reader for laundry application is chosen as an example to prove the concept and verify the performance. We found that the communication area between the tag and off-the-shelf HF-RFID reader is improved. The proposed technique is useful for antenna improvement of off-the-shelf HF-RFID system in many applications such as laundry application, product tacking, etc. where a short range with wide communication area are required.

2. Propagation Models for Wireless Mesh Networks In this paper we evaluate the influence ofradio propagation modeling on VoIP quality in wireless network simula-Propagation models are classified as large-scale (estitions. How propagation modeling can influence classificamates the signal strength considering power degradation in tion ofstrategies concerned in improving VoIP quality? We wave propagation path, also known as path loss) and smallanalyze reactive AODV andproactive OLSR approaches in scale or fading models (captures variations of the signal a simulated 802.11 Mesh Backbone and calculate the VoIP strength over short time durations) [9]. quality by means ofa reviewed version ofITU-TE-Model. Standard ns-2 only includes path-loss models, while a Results showed that: a) irrespective ofrouting strategy, fading model is expected to ns version 3. According to [7], different propagation model configurations can influence ns-2 makes use of shadowing model incorrectly because speech quality in such a way that it switches from "aceach frame sees different path loss estimations in a radio ceptable" to "unacceptable", b) the classification ofsuch communication. But, although the model is stochastic, it is strategies can be highly influenced by propagation models fixed as long as the two nodes are stationary and not adeas well as its configurations. quate to express temporal variation of the radio channel. To a deeper discussion about propagation models, refer to [9].

This paper systematically examines the response to QuasiMoment-Method (QMM) calibration, of the basic COST231Walfisch-Ikegami, ITUR-Walfisch-Ikegami, and WalfischBertoni models. First, it is demonstrated that the component parameters of the models are suitable candidates for use as expansion/testing functions with QMM pathloss model calibration schemes; and thereafter, the basic models are subjected to calibration, using measurement data available in the open literature. Computational results reveal that the COST231-Walfisch-Ikegami and ITU-Walfisch-Ikegami models have virtually identical QMM-calibration root mean square error (RMSE) responses; and that the Walfisch-Bertoni model has better RMSE responses than both of them. A particular attribute revealed by the simulation results is that all QMM-calibrated ‘Walfisch-type’ basic models have excellent mean prediction error (MPE) metrics (in general, less than 0.001dB). In addition to pathloss prediction profiles, the paper also prese...

This paper systematically examines the response to QuasiMoment-Method (QMM) calibration, of the basic COST231Walfisch-Ikegami, ITUR-Walfisch-Ikegami, and WalfischBertoni models. First, it is demonstrated that the component parameters of the models are suitable candidates for use as expansion/testing functions with QMM pathloss model calibration schemes; and thereafter, the basic models are subjected to calibration, using measurement data available in the open literature. Computational results reveal that the COST231-Walfisch-Ikegami and ITU-Walfisch-Ikegami models have virtually identical QMM-calibration root mean square error (RMSE) responses; and that the Walfisch-Bertoni model has better RMSE responses than both of them. A particular attribute revealed by the simulation results is that all QMM-calibrated ‘Walfisch-type’ basic models have excellent mean prediction error (MPE) metrics (in general, less than 0.001dB). In addition to pathloss prediction profiles, the paper also prese...

I would like to thank the various people involved in making this project a success. First and foremost, I would like to express my deep appreciation to my final year project supervisor, Dr. Mohamad Naufal Bin Mohamad Saad for giving me the opportunity to do this project under his supervision. I would like to thank him for his time in monitoring my progress. I am personally grateful for his commitment, advice, encouragement, guidance and patience throughout the duration of the project. Special gratitude to Mr. Salehan, ITMS staff, who found time in a very busy schedule to guide me in completing the fabrication of the antenna and sharing his technical knowledge regarding communication field. His passion for communication field has really inspired me. I am deeply indebted to him who helps me in testing the antenna and willing to offer the equipments for the testing. I would like to thank him for his commitment, advice, encouragement and guidance. My acknowledgement then goes to my colleagues for supporting me in my project. I want to thank them for all their help, support, interest and valuable hints. Finally, I am sincerely grateful to my family their financial and emotional support throughout this course in order for me to complete my final year project.

To minimize the impact of human activities on marine fauna, efforts need to be taken to reduce underwater noise due to shipping by first defining procedures to measure radiated noise from ships. The signal received by a hydrophone array placed in the vicinity of the ship depends on the environment and the measurement configuration. For deep waters, standards have been published to estimate the noise source level taking into account the geometric losses and the effect of the surface. In shallow waters, underwater acoustic propagation is influenced by the interactions with the surface and the sea bottom. Using numerical simulation, an empirical formula has been defined to correct the influence of the environment and estimate the noise source level. However, this empirical formula is only valid for sandy bottoms. The present work aims at correcting the formula to extend its validity to more types of sea bottom. Simulations are carried out using the open source codes: wavenumber integration in the low frequency range and beam-tracing in the high frequency range. The influence of shear waves in the sea floor is going to be investigated. Robustness of the empirical formula will be tested on different water depths and measurement ranges.

A storm, composed of two delayed cells, hit the Monte Antelao slopes (Dolomites, North Eastern Italy) in the early morning of July 18 th , 2009. The resulting runoff triggered two consecutive debris flows along the Rovina di Cancia channel. The detailed topographic data collected before and just after this event allowed an accurate reconstruction of the morphological changes experienced by the channel bed. These data are here used as benchmark to test the ability of numerical models to reproduce the dynamics of a real event, taking into account the morphology changes of the channel bed. The aim is to provide an efficient model for engineering applications

I would like to thank the various people involved in making this project a success. First and foremost, I would like to express my deep appreciation to my final year project supervisor, Dr. Mohamad Naufal Bin Mohamad Saad for giving me the opportunity to do this project under his supervision. I would like to thank him for his time in monitoring my progress. I am personally grateful for his commitment, advice, encouragement, guidance and patience throughout the duration of the project. Special gratitude to Mr. Salehan, ITMS staff, who found time in a very busy schedule to guide me in completing the fabrication of the antenna and sharing his technical knowledge regarding communication field. His passion for communication field has really inspired me. I am deeply indebted to him who helps me in testing the antenna and willing to offer the equipments for the testing. I would like to thank him for his commitment, advice, encouragement and guidance. My acknowledgement then goes to my colleagues for supporting me in my project. I want to thank them for all their help, support, interest and valuable hints. Finally, I am sincerely grateful to my family their financial and emotional support throughout this course in order for me to complete my final year project.

Nowadays, implanted medical devices that are using inductive coupling for communication, cannot be used for transmitting medical data in several meters range. This triggers us to study about implantable device systems in order for communications is enabled to be longer range by transmitting wirelessly electromagnetic signal. In this system, the external devices such as home monitoring device or portable equipment will provide the patient more mobility, and the patient or the health care provider could benefit from timely and ease of access to important patient medical information via a networked connection. Due to such advantages, small antennas for implantable devices are very important components in monitoring systems to provide wirelessly communication between a patient and an access point. This paper proposes a simple structure of a folded dipole antenna for an implantable device aimed at wireless patient monitoring applications. The implantable device is assumed to be used with a syringe injection, so the device can be simply embedded into the human body. The antenna is operated in UHF band 924 MHz, which is band of Indonesian frequency allocation for RFID applications. The antenna is small enough in this band with good performances such as S parameter, impedance bandwidth, radiation pattern and gain. The antenna has enough gain for more than 10m range communication with 250 MHz bandwidth (VSWR 1.5).

A miniaturized UHF dual-band passive RFID tag antenna operating in the 866-869 and 950-956 MHz bands is proposed. It consists of an S-shaped Folded Dipole Antenna (FDA) resonating at 912 MHz, which is intermediary between the two required frequencies. To obtain dualband response perturbation method is employed. The electrical length of the FDA changes on loading a 2-turn spiral resonator (2-SR) to it. The 2-SR splits the tag resonance at 912 MHz into two resonance frequencies (867 and 956 MHz). The proposed design is simulated using HFSS and then fabricated. Measured reflection coefficients at 867 and 956 MHz are −13.25 and −13.34 dB, respectively, exhibiting a 10 dB bandwidth of 11 MHz from 859 to 869 MHz and a 5 MHz 10 dB bandwidth from 953 to 957 MHz. Maximum read ranges of 5 m in 866-869 MHz and 3.3 m in 950-956 MHz band have been measured.

Polyvinyl chloride (PVC) pipes are extensively used in municipal sewer systems. As the sewer piping networks are aging, PVC pipes are prone to developing cracks that can release toxic effluents into the environment. Traditionally, to monitor defects in PVC pipes, utility operators pass a close circuit TV (CCTV) camera mounted on a guided vehicle through the pipe. The video is observed by a trained operator who records condition of the pipe. This arrangement, suffers from two major limitations. One, it is expensive due to complex set up and second, if a pipe is blocked the guided vehicle cannot pass through its entire length. A more economical and robust system is needed that can reliably detect cracks in sewer pipes. Our approach is based on measuring acoustic signal attenuation in a cracked pipe and comparing it with attenuation in a pipe with no cracks. This study is work in progress and preliminary results from laboratory test setup are presented. Testing in actual sewer installations is being planned and results will be reported in future. An Acoustic-Based Approach for Conditioning Monitoring of Pipes

In this paper we provide new recommendations for a type of antenna design in applications where a human is present in the vicinity of a wireless power transfer (WPT) system by means of power transfer efficiency (PTE) and specific absorption rate (SAR). The interaction between a homogenous human model and different WPT systems is investigated at 13.56 MHz using spherical mode theory antenna model (SMT-AM) and full-wave numerical analysis. The human model exposure and the performance of the proposed WPT system are analyzed further for some typical scenarios. It is shown that the position in which the human model is closer to the receiver is favorable over the position closer to the transmitter, concerning both PTE and SAR. Also, the consideration of variable receiver load indicates that different levels of SAR coupled by degraded PTE can be expected. The proposed antennas are designed, and proof of concept WPT measurements are carried out.

This article proposes an adaptive-network-based fuzzy inference system (ANFIS) model for accurate estimation of signal propagation using LoRaWAN. By using ANFIS, the basic knowledge of propagation is embedded into the proposed model. This reduces the training complexity of artificial neural network (ANN)-based models. Therefore, the size of the training dataset is reduced by 70% compared to an ANN model. The proposed model consists of an efficient clustering method to identify the optimum number of the fuzzy nodes to avoid overfitting, and a hybrid training algorithm to train and optimize the ANFIS parameters. Finally, the proposed model is benchmarked with extensive practical data, where superior accuracy is achieved compared to deterministic models, and better generalization is attained compared to ANN models. The proposed model outperforms the nondeterministic models in terms of accuracy, has the flexibility to account for new modeling parameters, is easier to use as it does not ...

Estimates of the noise source spectra of ships based on long term measurements in the Baltic sea are presented. The measurement data were obtained by a hydrophone deployed near a major shipping lane south of the island Öland. Data from over 2,000 close-by passages were recorded during a 3 month period from October to December 2014. For each passage, ship-to-hydrophone transmission loss (TL) spectra were computed by sound propagation modeling using 1. bathymetry data from the Baltic Sea Bathymetry Database (BSBD), 2. sound speed profiles from the HIROMB oceanographic model, 3. seabed parameters obtained by acoustic inversion of data from a calibrated source, and 4. AIS data providing information on each ship's position. These TL spectra were then subtracted from the received noise spectra to estimate the free field source level (SL) spectra for each passage. The SL were compared to predictions by some existing models of noise emission from ships. Input parameters to the models, including e.g., ship length, width, speed, displacement, and engine mass, were obtained from AIS (Automatic Identification System) data and the STEAM database of the Finnish Metereological Institute (FMI).

Since Nikola Tesla discovered wireless power transmission, it has become a very interesting topic of study in the antennas and wireless propagation community. Various aspects and applications for wireless power transmission are studied today, a few of which are investigated in this work. First, various antenna geometries are analyzed for radiative near-field wireless power transfer in terms of electrical field strength. It is determined that the meander antenna is ideal for maximum power transfer in its radiative near-field region, contrary to its far-field behavior. Next, in the application of radio frequency identification, a directive, UHF RFID tag antenna is designed for pavement embedded applications. The antenna covers 72% of the US required bandwidth (902-928 MHz) in measurement and has maximum directivity and read range of 7.38 dBi and 14.2ft (4.3 m), respectively. Although the transmitter and receiver antennas' designs are essential parts of the wireless system, power loss to the wireless channel is another critical factor to consider in ensuring the receiver antenna receives the maximum power. Friis transmission equation is studied in detail, and a section of the Georgia Southern University campus is considered for full cellular coverage in the GSM frequency range. Additionally, using the genetic algorithm in parallel, the optimal position for a 60-GHz wireless router is determined to obtain maximum WIFI coverage in a specific house. Finally, the design procedure for a size-reduced, 15-element Yagi antenna is discussed. A comprehensive comparison is conducted demonstrating the importance of the antenna design, with its similar performance to the full-sized Yagi antenna, while its elements are reduced by 45%.

In this paper we focus on the following question: how routing protocols, working under different channel conditions, can influence the human perceived quality of VoIP calls in a wireless mesh backbone? In order to respond this question, we propose a study case where we analyze two routing approaches in a 802.11 Wireless Mesh Backbone, namely, reactive AODV and proactive OLSR. We calculated the voice speech quality by making use of a reviewed version of ITU-T E-Model proposed in previous work. Results obtained from highly credible stochastic simulation environment, also described in this paper, showed that AODV performs better in very hostile mediums while OLSR presents better results when more friendly mediums take place.

In this paper we focus on the following question: how routing protocols, working under different channel conditions, can influence the human perceived quality of VoIP calls in a wireless mesh backbone? In order to respond this question, we propose a study case where we analyze two routing approaches in a 802.11 Wireless Mesh Backbone, namely, reactive AODV and proactive OLSR. We calculated the voice speech quality by making use of a reviewed version of ITU-T E-Model proposed in previous work. Results obtained from highly credible stochastic simulation environment, also described in this paper, showed that AODV performs better in very hostile mediums while OLSR presents better results when more friendly mediums take place.

In this paper we focus on the following question: how routing protocols, working under different channel conditions, can influence the human perceived quality of VoIP calls in a wireless mesh backbone? In order to respond this question, we propose a study case where we analyze two routing approaches in a 802.11 Wireless Mesh Backbone, namely, reactive AODV and proactive OLSR. We calculated the voice speech quality by making use of a reviewed version of ITU-T E-Model proposed in previous work. Results obtained from highly credible stochastic simulation environment, also described in this paper, showed that AODV performs better in very hostile mediums while OLSR presents better results when more friendly mediums take place.

In this paper we focus on the following question: how routing protocols, working under different channel conditions, can influence the human perceived quality of VoIP calls in a wireless mesh backbone? In order to respond this question, we propose a study case where we analyze two routing approaches in a 802.11 Wireless Mesh Backbone, namely, reactive AODV and proactive OLSR. We calculated the voice speech quality by making use of a reviewed version of ITU-T E-Model proposed in previous work. Results obtained from highly credible stochastic simulation environment, also described in this paper, showed that AODV performs better in very hostile mediums while OLSR presents better results when more friendly mediums take place.