This article considers the fusion of target estimates stemming from multiple sensors, where the spatial extent of the targets is incorporated. The target estimates are represented as ellipses parameterized with center orientation and semi-axis lengths and width. Here, the fusion faces challenges such as ambiguous parameterization and an unclear meaning of the Euclidean distance between such estimates. We introduce a novel Bayesian framework for random ellipses based on the concept of a Minimum Mean Gaussian Wasserstein (MMGW) estimator. The MMGW estimate is optimal with respect to the Gaussian Wasserstein (GW) distance, which is a suitable distance metric for ellipses. We develop practical algorithms to approximate the MMGW estimate of the fusion result. The key idea is to approximate the GW distance with a modified version of the Square Root (SR) distance. By this means, optimal estimation and fusion can be performed based on the square root of the elliptic shape matrices. We analyze different implementations using, e.g., Monte Carlo methods, and evaluate them in simulated scenarios. An extensive comparison with state-of-the-art methods highlights the benefits of estimators tailored to the Gaussian Wasserstein distances.

Vehicle-to-Everything (V2X) using Visible Light Communication (VLC) channels can be seen as an economically viable option to replace the existing modes of vehicular communications in the near future. In this paper, we have analyzed the performance of VLC based V2X communication under various environmental deterrents viz. Light Fog, Dense Fog, Light Smoke and Dense Smoke using a proof-of-concept testbed. A series of experiments were conducted to investigate the effects of environmental deterrents over VLC based Line-of-Sight as well as non-Line of Sight V2X transmission with respect to distance and angular variations. On-Off-keying (OOK) modulation has been selected as the modulation scheme, as defined in VLC standard (IEEE 802.15.7) for the transmission of information bits between a transmitter LED and a photo-diode receiver. The experimental results show the feasibility of VLC-based V2X systems with reliable data transmission under different environmental deterrents with a fairly good signal-to-noise ratio (SNR), even under dense-fog and smoke conditions where the attenuation in average optical power at the receiver, is quite high.

Positioning is a fundamental issue for mobile robots. Therefore, a performance analysis is suitable to determine the behavior of a system, and to optimize its working. Unfortunately, some systems are only evaluated experimentally, which makes the performance analysis and design decisions very unclear. In [4], we have proposed a new angle measurement system, named BeAMS, that is the key element of an algorithm for mobile robot positioning. BeAMS introduces a new mechanism to measure angles: it detects a beacon when it enters and leaves an angular window. A theoretical framework for a thorough performance analysis of BeAMS has been provided to establish the upper bound of the variance, and to validate this bound through experiments and simulations. It has been shown that the estimator derived from the center of this angular window provides an unbiased estimate of the beacon angle. This document complements our paper by going into further details related to the code statistics of modulated signals in general, with an emphasis on BeAMS. In particular, the probability density function of the measured angle has been previously established with the assumption that there is no correlation between the times a beacon enters the angular window or leaves it. This assumption is questionable and, in this document, we reconsider this assumption and establish the exact probability density function of the angle estimated by BeAMS (without this assumption). The conclusion of this study is that the real variance of the estimator provided by BeAMS was slightly underestimated in our previous work. In addition to this specific result, we also provide a new and extensive theoretical approach that can be used to analyze the statistics of any angle measurement method with beacons whose signal has been modulated. To summarize, this technical document has four purposes: (1) to establish the exact probability density function of the angle estimator of BeAMS, (2) to calculate a practical upper bound of the variance of this estimator, which is of practical interest for calibration and tracking (see Table 1, on page 13, for a summary), (3) to present a new theoretical approach to evaluate the performance of systems that use modulated (coded) signals, and (4) to show how the variance evolves exactly as a function of the angular window (while remaining below the upper bound).

Study of downlink secrecy rate in Massive MIMO employing 1-bit ADCs/DACs in the presence of pilot attack

JPL’s own data correlate to 1% NEAR and Rosetta trajectory discrepancies to an unexpected doubling of path times in phase locked tracking. NEAR’s radar residuals illustrate the doubling to 5σ. Analysis of these and other NASA-tracked flybys shows that a distance sensitive anomalous signal generally exists. (Presented at IEEE NAECON 2019)

The recovery of sparse signals given their linear mapping on lower-dimensional spaces can be partitioned into a support estimation phase and a coefficient estimation phase. We propose to estimate the support with an oracle based on a deep neural network trained jointly with the linear mapping at the encoder. The divination of the oracle is then used to estimate the coefficients by pseudo-inversion. This architecture allows the definition of an encoding-decoding scheme with state-of-the-art recovery capabilities when applied to biological signals such as ECG and EEG, thus allowing extremely low-complex encoders. As an additional feature, oracle-based recovery is able to self-assess, by indicating with remarkable accuracy chunks of signals that may have been reconstructed with a non-satisfactory quality. This self-assessment capability is unique in the CS literature and paves the way for further improvements depending on the requirements of the specific application. As an example, our scheme is able to satisfyingly compress by a factor of 2.67 an ECG or EEG signal with a complexity equivalent to only 24 signed sums per processed sample.

The outputs of a cross-polarized antenna can produce a pair of different parallel frequency-selective channels. The optimum combining strategy is derived from maximum likelihood principles and used to define an equivalent discrete-time model. The simulated post-equalizer BER results show that optimum combining produces the best results, selection diversity can provide reasonably good results, and that both optimum combining and selection diversity can be superior to linear equalizer operating on the channel obtained by combining the antenna outputs before applying a channel matched filter.

This paper presents some new and explicit stability results for Volterra systems from two different approaches. The first approach is based on monomial domination of the Volterra system's memoryless output nonlinearity and the second on its Lipschitz-norm. The former yields more widely applicable results, but introduces nonconvexity in the signal spaces for certain parameter values.

THIS PREPRINT IS NOW ISSUED AS IEEE ACCESS https://ieeexplore.ieee.org/document/10231329 The CENELEC TS 50701 is the first encompassing standard aiming at  governing cybersecurity risk management processes within the railway  industry. Although the technical maturity of this framework is  undeniable, its application in practical projects is still an active  field of discussion among practitioners, especially when dealing the  communication-heavy subsystems. Among such subsystems, signaling is  among the most critical ones. Both Communication-based Train Control  (CBTC) and European Railway Traffic Management Systems (ERTMS) heavily  rely on wireless communications for their operation. This paper  describes two cybersecurity attack scenarios regarding wireless  communications for CBTCs that can impact the safety of these systems  using the lens of the framework provided by the novel CENELEC TS 50701.  In doing so, we discuss the implications of using such guidance,  especially concerning the different interpretations found in the  literature regarding zoning communication systems, to assess and  mitigate the cybersecurity risk and improve the posture of CBTC systems  concerning the examined attacks. Experimental tests conducted in  controlled laboratory environments and high fidelity simulations have  been conducted to support the cybersecurity analysis.