Bluetooth Low Energy (BLE) is a recently developed energy-efficient short-range wireless communication protocol. In this paper, we discuss and compare the maximum peer-to-peer throughput, the minimum frame turnaround time, and the energy consumption for three protocols, namely BLE, IEEE 802.15.4 and SimpliciTI. The specifics and the main contributions are the results both of the theoretical analysis and of the empirical measurements, which were executed using the commercially available hardware transceivers and software stacks. The presented results reveal the protocols' capabilities and enable one to estimate the feasibility of using these technologies for particular applications. Based on the presented results, we draw conclusions regarding the feasibility and the most suitable application scenarios of the BLE technology.

The prediction models for tropospheric scintillation on earth-satellite paths from Karasawa, Yamada, and Allnutt and ITU-R are compared with measurement results from satellite links in Europe, the United States, and Japan at frequencies from 7 to 30 GHz and elevation angles of 3 to 33. The existing prediction models relate the long-term average scintillation intensity to the wet term of refractivity at ground level. The comparison shows that the seasonal variation of scintillation intensity is well predicted by this relation, but for the annual average some additional meteorological information is needed. A much better agreement with measurement results is found when a parameter representing the average water content of heavy clouds is incorporated. This confirms the assumption that scintillation is, at least partly, associated with turbulence inside clouds. The asymmetry between the distributions of signal fade and enhancement can also be explained by turbulence inside clouds. The asymmetry depends on the intensity of the scintillation, which is consistent with the theory assuming a thin layer of cloudy turbulence. A new model based on this theory predicts the distributions of signal fade and enhancement significantly better.

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In this article the results for study of the influence of different microcontroller hardware parameters on the system overall power consumption and thus also on the system lifetime are presented. The influence of the supply voltage, clock frequency and emplacement of the program in the microcontroller memory for MSP430 microcontroller, which is often used nowadays in Wireless Sensor Networks (WSN) nodes, were evaluated. Additionally, we have studied the influence of different power supply systems for the node lifetime and figured out the optimal microcontroller working mode parameters, which allowed to maximize the amount of microcontroller operations for power supply charge using a normal battery and an energy harvesting system based on light energy harvesting. Although the motivation of this article has been the requirements of energy efficient WSN solutions obtained results are as well applicable to any microcontroller based embedded system that is working in harsh energy conditions.

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