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We analyze the downlink of a massive multiuser multiple input, multiple output (MIMO) system where antenna units at the base station are connected in a daisy chain without a central processing unit and only possess local channel knowledge. For this setup, we develop and analyze a linear precoding algorithm for suppressing interuser interference. It is demonstrated that the algorithm is close to ze
Future internet-of-things systems need to be able to combine heterogeneous services and support weak connectivity. In this paper, we introduce ComPOS, a new domain-specific language for composing services in IoT systems. We show how Maria, a bird watcher, can use ComPOS to build a system that allows her to spy on birds in the garden while she is not at home. We demonstrate how ComPOS handles the u
Reliable wireless communication links are a critical but challenging aspect for high-speed railway (HSR). To develop and analyze such systems, accurate models for the propagation channel are required. The radio channel properties in HSR scenarios are different from those in cellular scenarios not only due to the high velocity, but also due to the special construction elements and the type of surro
This paper presents a 16-lane, 16-bit complex application-specific instruction processor (ASIP) for baseband processing in massive multiple-input multiple-output (MIMO). The architecture utilizes a 3/4-way very large instruction word (VLIW) with highly efficient pre- and post-processing units specifically trimmed for massive MIMO requirements. Architecture optimizations include features like singl
Millimeter-wave (mmWave) systems must overcome severe phase noise impairment to exploit its full advantage (e.g. high data rate). However, the estimation of phase noise combined with wireless channel requires not only high-computational complexity, but also does not guarantee a stable solution. In this paper, the fact that the coherence bandwidth of a mmWave system is much larger than those of con
This chapter is dedicated to radio channel measurement and modelling techniques for beyond 4G networks, in particular: • new measurement techniques not only targeting radio channels, but also material properties in new frequency bands (Section 9.1), • improved physical models, cowering full-wave as well as ray-based methods, with a specific sub-section dealing with diffuse scattering (DS) and comp
The harmonic oscillator is a truly irreplaceable as well as ubiquitous analog integrated circuit. Starting from the basics of its CMOS implementation, we will discuss the phase noise of the harmonic oscillator in some detail, where the intrinsic large-signal operation mandates a time-variant analysis. This will be followed by a survey of the most popular design techniques enabling a low phase nois
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
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
In this paper a synchronized dual input-channel multi-mode Software Defined Radio receiver platform that we built originally is presented. The receiver platform compatible with the GSM, WCDMA, and Wi-Fi standards can detect and identify the surrounding base stations and access points. It features wide frequency range, high adaptive sampling rate and especially dual phase coherent receiving channel
The purpose of the risk management process, RiskUse is to provide practitioners, mainly risk managers with a software risk management process that has a well-defined user perspective. The aim is to present a risk management process that allows the development organisation to perform adequate risk management activities that can ensure that the developed software is safe from a user perspective.
Abstract in UndeterminedThe scalability of intelligent transport systems (ITS) applications is difficult to test in a field operational test (FOT) due to the high number of ITS equipped vehicles required. Therefore, computer simulations for evaluating different wireless communication technologies for ITS different applications can serve as a complement. In this paper we present results from lab me
