Passenger trains and especially metro trains have been identified as one of the key scenarios for 5G deployments. The wireless channel inside a train car is reported in the frequency range between 26.5 GHz and 40 GHz. These bands have received a lot of interest for high-density scenarios with a high-traffic demand, two of the most relevant aspects of a 5G network. In this paper we provide a full description of the wideband channel estimating Power-Delay Profiles (PDP), Saleh-Valenzuela model parameters, time-of-arrival (TOA) ranging, and path-loss results. Moreover, the performance of an automatic clustering algorithm is evaluated. The results show a remarkable degree of coherence and general conclusions are obtained.
Ray Launching is a deterministic method for modeling radio wave propagation based in the Geometric Optic theory. This method is very efficient in three-dimensional and complex environments like inside buildings. But some problems appear implementing the reception algorithms, because the receptors are considered punctual and the rays haven't thickness. The Reception Sphere method is a popular technique used to fix this problem. An alternative method is to launch three-dimensional tubes, instead of rays. In this paper, both techniques are analyzed, showing the advantages and disadvantages of each one in efficiency and accuracy.
Due to the vertiginous increase of the electromagnetic emissions of the modern communication systems and to the affected population's concern, it becomes necessary a more exhaustive control of this type of contamination. There are available different measure devices that make a characterization of the received emissions, but most does not discriminate between the contributions from different systems. Therefore, you cannot identify the systems responsible for the excessive measured levels. Of all the studied devices, the one that better it fulfils the expectations it is the spectrum analyzer, that it allows to characterize the received emissions, separating the different bands of the spectrum, and isolating the frequencies that don't perform the existent norm. To control the spectrum analyzer we have developed a software program that makes the measures according to the procedure exposed in the standard. Finally, another program processes and it represents the results of the measures. In addition, this application can calculate the theoretical level of radiation of different communication systems by simulation approximations and then, to compare with the measurement levels and with the reference level.
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