7 research outputs found

    Comparative study of Radio Mobile and ICS Telecom propagation prediction models for DVB-T

    Get PDF
    In this paper, a comparative study between the results of a measurement campaign conducted in northern Greece and simulations performed with Radio Mobile and ICS Telecom radio planning tools is performed. The DVB-T coverage of a transmitting station located near the city of Thessaloniki is estimated using three empirical propagation models (NTIA-ITS Longley Rice, ITU-R P.1546 and Okumura-Hata-Davidson) and one deterministic model (ITU-R 525/526). The best results in terms of minimum average error and standard deviation are obtained using the deterministic model and the NTIA-ITS Longley Rice empirical model. In order to improve the results, the tuning options available in the ICS Telecom software are used on the Okumura-Hata-Davidson model, leading to a significant increase in accuracy

    Evaluation of prediction accuracy for the Longley-Rice model in the FM and TV bands

    Get PDF
    Accurate geographical coverage predictions maps for FM and TV are needed for channel and frequency allocations and in order to avoid unwanted interferences. The Longley-Rice model has been used for this purpose over the last four decades and still being used almost exclusively by the FCC in the United States. In this work a comparison is presented between the relative accuracy of this model in the VHF-FM and UHF-TV frequency bands. Simulations were made with accurate and up to date input data (antenna height, location, gain, transmit power, etc.) for the FM-TV stations provided by the ERT S.A. public broadcaster in the region of Thessaloniki – Greece. Finally, the calculated – simulated results were confronted to field measurements using a Rohde & Schwarz FSH3 portable spectrum analyzer and high precision calibrated biconical and log-periodic antennas, and the errors between predictions and measurements were statistically analyzed in the two frequency bands. It has been found in this study that the Longley-Rice model, in general, overestimates field-strength values, but this overestimation is much higher in the VHF – FM radio band (88-108 MHz) than in the UHF-TV band (470-790 MHz)

    Coverage Determination of Incumbent System and Available TV White Space Channels for Secondary Use in Ethiopia

    Get PDF
    Different path loss modelsare used to analyze the behavior of terrestrial television signals. The path loss calculated by one model differs from the other depending on different factors they consider. Frequency is one of the main factors included in each model. The frequency variation in the electromagnetic spectrum causes different response for each model. In terrestrial TV signal representation, since it is operating under VHF and UHF spectrum range, the propagation model used to model the signal must be less invariant when the transmitter is operating in VHF and UHF. If the pathloss model used is very variant it is difficult to define the coverage of the transmitters. This causes interference among transmitters and between the digital terrestrial TV transmitters and TV white space devices. Different propagation models are analyzed by their sensitivity to frequency variation from very-high and ultra-high frequency spectrums. After the best model is selected, we have used this model to find the coverage of the incumbent transmitter, which then is used to analyze free channels for secondary use. First the pathloss at VHF and then for UHF is calculated. This difference is then compared and the result indicates that ITU-R P.1546–5, which incorporate terrain data is best of others. Using this model and further analyze the coverage and free channels, we have found a minimum of 408 MHz free contiguous bandwidth, by considering a worst-case scenario, which is placing a WSD at the incumbent transmitter

    Weather-Based Nonlinear Regressions for Digital TV Received Signal Strength Prediction

    Get PDF
    In this research, the impact of various weather conditions on digital television signals is investigated. Machine learning and nonlinear regression models were used to estimate the strength of the received signal. The received signal strength might vary significantly depending on the weather condition, especially in higher frequency ranges or millimetre wavelengths. Predictive analysis was performed for the radio-relay link Aval Tower-VrĆĄac Hill, which is used for the distribution of television and radio programmes by the public company Broadcasting Technology and Connections in Serbia. The prediction was made using temperature, temperature index, relative humidity, and received signal strength data for the months of June, July, and August in 2022. The best results were obtained using the RandomForest model. Extreme variations in the strength of the received signal can be predicted by using the model mentioned above. More effective management of the broadcasting infrastructure can be done with the ability to predict sudden falls and fluctuations in received signal strength
    corecore