Filetype
Augmented Reality (AR) has emerged as a technology able to greatly support the interaction between people and digital information by merging virtual objects with the real environment. So far, research in this field has been mainly focused on single-user scenarios with pre-stored digital data whose visualization needs to be appropriately and promptly aligned with physical objects. Instead, latest d
Given a set of commodities and a network where some arcs can fail while others are reliable, we first consider the problem of computing a minimum-cost pair of paths not sharing failing links. If a reliable link belongs to both paths then its cost is counted only once. We show that this problem can be solved in strongly polynomial time. Second, we consider a routing problem where each commodity can
Recently, it has been shown that a parasitic element can be used to fully decouple closely spaced antennas. However, the decoupled antennas suffer from narrow bandwidth, as compared to the bandwidth of isolated single antennas, which is also the case for other decoupling methods, such as multiport conjugate match and neutralization line. In this paper, we investigate the potential in bandwidth enh
Massive MIMO has been shown, both in theory and through experiments, to offer very promising properties. These include the possibility to decrease output power by at least an order of magnitude while still achieving large gains in spectral efficiency, as compared to today’s access schemes. To efficiently design communication algorithms and evaluate massive MIMO schemes, channel models that capture
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
Multiplexing efficiency is proposed as a simple and intuitive metric for characterizing multiple antenna systems in the spatial multiplexing mode of operation. Instead of comparing channel capacities of MIMO systems with different antennas, the metric offers valuable insights into the impact of antenna efficiency, efficiency imbalance and correlation on multiplexing performance. It is particularly
In this paper, we study the influence of current localization on the isolation between two antennas in a compact terminal setting. The two antennas are chosen to be a monopole and a PIFA, respectively. The degree of current localization is controlled by the permittivity value of the PIFA’s dielectric loading. Both lossless and lossy cases are simulated in order to ascertain the underlying performa
It is known that the compactness of mobile terminals complicates the design of multiple antennas, since coupling between the antennas increases when they are placed in proximity of one another. While it is possible to mitigate coupling between closely spaced antennas, a tradeoff in bandwidth is required. In this paper, we highlight ground plane excitation as an additional dimension to consider in
This paper presents a 28 GHz QVCO intended to be used in an 81-86 GHz E-band transceiver. E-band transceivers using e.g. 16 QAM modulation schemes are sensitive to I/Q phase error. Already a three degree error significantly degrades the bit error rate, and careful control of the phase error of the 28 GHz QVCO is therefore required. In the presented design the phase error can be tuned using four va
In many application domains, critical systems must comply with safety standards. This involves gathering safety evidence in the form of artefacts such as safety analyses, system specifications, and testing results. These artefacts can evolve during a system's lifecycle, creating a need for impact analysis to guarantee that system safety and compliance are not jeopardised. Although extensive resear
