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- Railways communications propagation prediction over irregular terrain using longley-rice modelPublication . Prior, Pedro; Cota, NunoThis paper presents the evaluation results of the radio signal propagation prediction using Longley-Rice model in railways installed in rural areas with significant variation of propagation path and terrain profiles. The prediction results were compared with measurement acquired by installing several CW emitters along the railway and reception equipment installed on a rolling stock. In addition, the results were also compared with the prediction based on Okumura-Hata model. The obtained results prove Longley-Rice suitability for railways communication prediction on irregular terrain, achieving better results than the Okumura-Hata model.
- On the use of okumura-hata propagation model on railway communicationsPublication . Cota, Nuno; Serrador, António; Vieira, Pedro; Beire, Ana Rita; Rodrigues, AntonioAlthough 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 900MHz 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 Global System for Mobile Communications-Railway pilot network, operating in Portugal.
- Optimizing propagation models on railway communications using genetic algorithmsPublication . Beire, Ana Rita; Pinheiro Pita, Helder Jorge; Cota, NunoAlthough the Okumura-Hata prediction model has been a widely used model to estimate radio network coverage, its application in railways environment requires calibration. The objective of this work is to present Genetic Algorithms as a solution in optimizing propagation models, proving that it can be used for optimizing the Okumura-Hata model on railway communications in order to improve its prediction of radio coverage. Several tests were carried out using different conditions allowing to establish the conditions that maximize the gain of the algorithm for this particular problem. The algorithm was applied to training samples and the resulting parameters were applied to different scenarios, showing improvements in the prediction results.
- Public mobile wideband networks interference impact assessment on railways GSM-R networkPublication . Rouco, André; Cota, Nuno; Beire, Ana Rita; Serrador, AntónioThis paper presents a field study relating to the impact that public operator cellular networks such as UMTS (Universal Mobile Telecommunication System), LTE (Long-Term Evolution), and 5G-NR (5G - New Radio) have on railway GSM-R (Global System for Mobile Communications – Railway) networks. The validation of the interference calculation relied on actual network measurements taken along railway lines using a dedicated probe. Emissions from public networks, in some scenarios, have been shown to affect GSM-R networks to a large extent. The developed algorithm is currently being used in real GSM-R network planning to mitigate this negative effect on base station coverage and service performance.