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Optimal data detection of data transmitted over a linear channel can always be implemented through the Viterbi algorithm (VA). However, in many cases of interest the memory of the channel prohibits direct application of the VA. A popular and conceptually simple method in this case, studied since the early 1970s, is to first filter the received signal in order to shorten the memory of the channel,

A 2.8-to-5.8 GHz harmonic VCO designed in a 28 nm UTBB FD-SOI CMOS process adopts a reconfigurable active core to save power at the lower oscillation frequencies, and to enable a trade-off between power consumption and phase noise at all frequencies. Interference caused by the magnetic coupling to and from the VCO inductor is greatly attenuated by resorting to an inductor in the shape of an 8. Sim

A 2.8-to-5.8GHz VCO designed in a 28nm UTBB FD-SOI CMOS process adopts a reconfigurable active core to save power at the lower oscillation frequencies, and to enable a trade-off between power consumption and phase noise at all frequencies. The UTBB FD-SOI CMOS process is instrumental to achieve a tuning range in excess of one octave at low power consumption, while the use of an 8-shaped tank coil

A digital phase-locked loop (DPLL) which uses a high resolution 2-dimension gated-Vernier time-to-digital converter (TDC) is presented. The shaped Vernier quantization of TDC greatly improves the in-band phase noise. Also the 2-dimension structure makes DPLL be able to process large phase errors almost without the influence of latency time. Combined with a high figure-of-merit (FOM) class-D digita

Empirical software engineering is a growing research area. Industrial experience gathered by systematic empirical case studies is extremely important for further evolution of the software engineering discipline. Scientific theory cannot provide effective means for software industry without fundamental understanding of the evolutionary development of complex software systems. However, there are cer

This paper presents a mutual coupling based calibration method for time-division-duplex massive MIMO systems, which enables downlink precoding based on uplink channel estimates. The entire calibration procedure is carried out solely at the base station (BS) side by sounding all BS antenna pairs. An Expectation-Maximization (EM) algorithm is derived, which processes the measured channels in order t

[Context and motivation] Ecosystems developed as Open Source Software (OSS) are considered to be highly innovative and reactive to new market trends due to their openness and wide-ranging contributor base. Participation in OSS often implies opening up of the software development process and exposure towards new stakeholders. [Question/Problem] Firms considering to engage in such an environment sho

Modeling tank losses in a harmonic oscillator by means of an equivalent parallel resistance may lead to an optimistic estimate of phase noise, as recently experienced in a class-D CMOS oscillator. The discrepancy is significant if two conditions are fulfilled: The single-ended portion of the tank capacitance displays a non-negligible loss, and the loop gain of the oscillator is very large; in the

In the vehicular communication channels, the mobility of the receiver (RX) and the transmitter (TX) along with the movements of interacting objects in the propagation environment result in significant non-stationary channel fading. The channel impulse response exhibits not just significant delay- and Doppler spreads, but also the delay- and Doppler spreads themselves are changing over the time- an

Today we have different location based services available in a mobile phone or mobile station (MS). These services include: direction finding to nearby ATMs, locating favorite food restaurants, or finding any target destination. Similarly, we see different applications of the positioning and navigation systems in firefighting or other rescue operations. The common factor in almost all of the locat

Technology scaling in advanced CMOS nodes has been very successful in reducing the cost and increasing the operating frequency, however, it has also resulted in reduced transistor intrinsic gain and increased thermal noise coefficient, and most importantly, deteriorated linearity performance. At the same time, advanced wireless communication standards offer ever increasing data rates and pose more

In this work, we analyze the use of a WiFi network deployed in a large-scale technical university. To this extent, we leverage three weeks of WiFi traffic data logs and characterize the spatio-temporal correlation of the traffic at different granularities (each individual access point, groups of access points, entire network). The spatial correlation of traffic across nearby access points is also

This paper presents a 2-dimension (2-D) Vernier time-to-digital converter (TDC) which uses two 3-stage gated-ring-oscillators (GROs) in the X/Y Vernier branches. The already small Vernier quantization noise (~10.6ps) is improved by the 1st-order noise shaping of the GRO. Moreover, since all delay differences between X phases and Y phases can be used (rather than only the diagonal line of the 1-dim

Numerous tools automating various aspects of software engineering have been developed, and many of the tools are highly configurable through parameters. Understanding the parameters of advanced tools often requires deep understanding of complex algorithms. Unfortunately, suboptimal parameter settings limit the performance of tools and hinder industrial adaptation, but still few studies address the

Implementation of open source development practices within commercial settings can bring benefits such as improved source code quality, lower maintenance costs, and increased innovation. However, a widespread in-house implementation of the practices has not been observed. The goal of this research is to understand factors which hinder the implementation. For the purpose, development practices of a

Software engineering considers performance evaluation to be one of the key portions of software quality assurance. Unfortunately, there seems to be a lack of standard methodologies for performance evaluation even in the scope of experimental computer science. Inspired by the concept of “instantiation” in object-oriented programming, we distinguish the generic performance evaluation logic from the

The spot pricing scheme has been considered to be resource-efficient for providers and cost-effective for consumers in the Cloud market. Nevertheless, unlike the static and straightforward strategies of trading on-demand and reserved Cloud services, the market-driven mechanism for trading spot service would be complicated for both implementation and understanding. The largely invisible market acti

Outdoor positioning systems are commonly available and typically rely on satellite navigation. The same is not true for indoor positioning systems. Severe multipath, non line-of sight to satellites and moving objects are some of the aspects that make the task of indoor positioning tricky. In this paper, we analyse different tracking methods to estimate and track the delay evolution of a radio chan