As the demand for mobile connectivity continues to grow, there is a strong need to evaluate the performance of Mobile Broadband (MBB) networks. In the last years, mobile "speed", quantified most commonly by data rate, gained popularity as the widely accepted metric to describe their performance. However, there is a lack of consensus on how mobile speed should be measured. In this paper, we design and implement MONROE-Nettest to dissect mobile speed measurements, and investigate the effect of different factors on speed measurements in the complex mobile ecosystem. MONROE-Nettest is built as an Experiment as a Service (EaaS) on top of the MONROE platform, an open dedicated platform for experimentation in operational MBB networks. Using MONROE-Nettest, we conduct a large scale measurement campaign and quantify the effects of measurement duration, number of TCP flows, and server location on measured downlink data rate in 6 operational MBB networks in Europe. Our results indicate that differences in parameter configuration can significantly affect the measurement results. We provide the complete MONROE-Nettest toolset as open source and our measurements as open data.

Articles you may be interested inScanning tunneling microscope measurements of the amplitude of vibration of a quartz crystal oscillator A new measuring method of magnetostrictive vibrationA new method is presented to measure in-plane vibration amplitudes of the order of some 10 nm. The measurement system utilizes the speckle effect and consists of only a few mechanical components. The evaluation is done by a microcomputer. The whole system is insensitive to environmental noise. The method has been applied to investigate the amplitude distribution of plano-convex AT -cut quartz crystals as they are commonly used in thin-film thickness monitors.

The three-dimensional equations of linear piezoelectricity are used to compute the mechanical vibration amplitude distributions, as well as the resonance frequencies of plano-convex circular AT-cut quartz crystal resonators. These computations are compared with vibration amplitude measurements employing a new technique that utilizes the speckle effect. Very good agreement has been found between the measured and the computed vibration amplitude distributions.

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