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The problem of estimating the state of a nonlinear dynamical system based on spline-approximation of functions is considered in the article. The resulted examples of use in the task of filtering and signal detection.
In this paper, we address the direction-of-arrival (DOA) estimation problem of hybrid completely polarized (CP) and partially polarized (PP) source signals with arbitrary polarimetric arrays. Firstly, oblique projection filtering operators, which are insensitive to the state of polarization of signals, are used to separate potential source signals in the spatial domain. Secondly, the DOA estimates...
Ultrasound shear wave elastography (SWE) is an emerging technique for characterizing local arterial stiffness - a known indicator for vascular health. However, the implications due to vascular anatomy and tissue environment are still relatively under-examined. Using polyvinyl alcohol (PVA) based tissue mimicking phantoms, this study assessed the current signal processing framework in demonstrating...
This work addresses the problems of frequency synchronization and channel estimation for OFDM/OQAM systems in Rayleigh fading channel. A two-step preamble based approach using a new frame structure is proposed. The first step is coarse carrier frequency offset (CFO) estimation and the second step is joint fine CFO (FCFO) and channel estimation. We also propose a FCFO estimator under the assumption...
Classic approaches to multi-channel signal enhancement rely on model assumptions regarding speech source relative transfer functions and noise covariance matrix, or on estimates thereof obtained in, e.g., speech pauses. To alleviate these constraints, we here investigate an approach to adaptive estimation of the speech (target) source and noise related acoustic parameters based on localized speech...
The steered response power (SRP) methods can be used to build a map of sound direction likelihood. In the presence of interference and reverberation, the map will exhibit multiple peaks with heights related to the corresponding sound's spectral content. Often in realistic use cases, the target of interest (such as speech) can exhibit a lower peak compared to an interference source. This will corrupt...
When noise is directional instead of diffuse, the majority of conventional direction of arrival (DOA) estimation techniques suffer from performance degradation because of mismatched noise models. In this paper, a novel robust DOA estimation algorithm is developed as an initial investigation into DOA estimation of speech under directional non-speech interference (DNSI) and non-directional background...
The work in this manuscript proposes to enhance the secrecy level of wireless systems through the use of a jamming technique that uses uncorrelated reciprocal channel estimations from the legitimate channel as a common random source to select discrete jamming signals in both sides of the legitimate link. After that selection, these jamming signals are combined with data at the legitimate transmitter,...
In this paper, a new algorithm to suppress the interferences for Direction-of-Arrival(DOA) estimation is presented. The method is based on the property of the noise subspace invariant to power of emitters. With theoretical analysis and computer simulations, it is shown that the proposed method has a good performance on signal DOA estimation under disturbances.
We are considering problem of estimating autoregressive signal coefficients over a network of agents. Noise and/or multipath are disturbing reception of the signals in network nodes. The autoregressive signals have different powers and delays at different nodes. Least-mean-square algorithms are used in nodes for the estimation as well as the cooperation strategy based on the adapt-then-combine diffusion...
Massive MIMO enables the improvement on the transmission rate without increasing the burden on the signal processing by employing a large number of antennas at a base station (BS). However, it is reported that CSI estimation itself has a large overhead when considering massive MIMO. The authors have proposed analog-digital hybrid massive MIMO configuration which eliminates CSI estimation itself by...
IEEE 802.11 Wlan networks are constantly challenged for maximum overall service performance and new mobility applications: real-time, interactive communications and presence analytics. They require a solid design approach that considers but not limited to: highly varying characteristics of dense environments, technology advances, feasibility of study hypotheses, and overall service design best practices...
The detection and localisation of multiple GNSS jammers in densely populated areas seems to be already a need due to the availability and proliferation of very cheap and small GNSS jammers (together with the raise of the privacy awareness), and the increasing number of services and applications relying on the GNSS signals for its operation. Densely populated areas do not only introduce the possibility...
New waveform candidates are being investigated for the fifth generation wireless systems. Among the promising candidates, generalized frequency division multiplexing (GFDM) offers the flexibility to address a wide range of requirements (e.g. low latency, coarse synchronization, etc.). Due to the non- orthogonality of GFDM, the transmit signal subjects to inter-symbol and inter-carrier interference...
The two major sources of disturbances for an efficient and reliable data transmission through power lines, known as power line communication (PLC), are impulsive noise (IN) and narrow band interference (NBI). In this paper, we propose an algorithm to cancel the IN and NBI simultaneously for an OFDM based PLC system. The proposed method exploits the duality of the problem, where the IN is sparse in...
The notion of Total Interference Degree (TID) is traditionally used to estimate the intensity of prevalent interference in a Multi-Radio Multi-Channel Wireless Mesh Network (MRMC WMN). Numerous Channel Assignment (CA) approaches, link-scheduling algorithms and routing schemes have been proposed for WMNs which rely entirely on the concept of TID estimates. They focus on minimizing TID to create a minimal...
The present work deals with optimized strategies to address the issue of link adaptation (Adaptive Coding and Modulation — ACM) in a multi-user multi-beam satellite system employing precoding at the gateway side. Accordingly, the focus is on the forward link of a multi-beam satellite system employing a full frequency reuse configuration. In such an interference limited setting, the Super-Framing structure...
Massive MIMO and beamforming is commonly considered as one of the key technologies for future cellular communications. It is targeted to solve the capacity requirements in enhanced mobile broadband and enable new services in other communication fields, e.g. machine type communications. In this work, we study M-MIMO technology in a novel approach, combining system simulations and modeling with hardware...
Wireless Networks are vulnerable to collisions and interferences from other radiation sources due to the broadcast nature of wireless channels. Collisions may occur when two or more stations sharing the physical medium transmit simultaneously. Contention-based protocols for medium access control (MAC) aim at reducing collisions in these networks. However, the presence of hidden terminals can still...
In this paper, we present a design methodology for synchrophasor estimation systems based on a convex semi-infinite optimization approach. Concretely, we present a suitable objective function for the problem and show how different performance constraints can be formulated. The advantage of this over most methods is that it allows us to control precisely and completely the behavior of the system on...
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