- document
-
Arroyo Valles, M.D.R. (author), Simonetto, A. (author), Leus, G.J.T. (author)In wireless sensor networks, where energy is scarce, it is inefficient to have all nodes active because they consume a non-negligible amount of battery. In this paper we consider the problem of jointly selecting sensors, relays and links in a wireless sensor network where the active sensors need to communicate their measurements to one or...journal article 2017
- document
-
Isufi, E. (author), Loukas, A. (author), Simonetto, A. (author), Leus, G.J.T. (author)Graph filters play a key role in processing the graph spectra of signals supported on the vertices of a graph. However, despite their widespread use, graph filters have been analyzed only in the deterministic setting, ignoring the impact of stochasticity in both the graph topology and the signal itself. To bridge this gap, we examine the...journal article 2017
- document
-
Ivashko, I. (author), Leus, G.J.T. (author), Yarovoy, Alexander (author)In this paper, we tackle the problem of selecting the radar node positions to provide an estimate of the target state vector with a prescribed accuracy. The topology optimization problem is formulated as selection of a fixed number of radar node positions from a set of available ones, where the radar observations are modeled by a general non...journal article 2017
- document
-
Hu, Y. (author), Leus, G.J.T. (author)Estimation problems in the presence of deterministic linear nuisance parameters arise in a variety of fields. To cope with those, three common methods are widely considered: (1) jointly estimating the parameters of interest and the nuisance parameters; (2) projecting out the nuisance parameters; (3) selecting a reference and then taking...journal article 2017
- document
-
Roy, V. (author), Gishkori, S.S. (author), Leus, G.J.T. (author)In this work, we propose a sparsity-exploiting dynamic rainfall monitoring methodology using rain-induced attenuation measurements from microwave links. To estimate rainfall field intensity dynamically from a limited number of non-linear measurements, we exploit physical properties of the rainfall such as spatial sparsity and non-negativity...journal article 2016
- document
-
Isufi, E. (author), Dol, H. (author), Leus, G.J.T. (author)Flooding-based protocols are a reliable solution to deliver packets in underwater sensor networks. However, these protocols potentially involve all the nodes in the forwarding process. Thus, the performance and energy efficiency are not optimal. In this work, we propose some advances of a flooding-based protocol with the goal to improve the...journal article 2016
- document
-
Ebihara, T. (author), Leus, G.J.T. (author)Underwater acoustic (UWA) channels are characterized by a severe spread in time and frequency, and are usually labeled as “doubly spread channels.” In this paper, we propose Doppler-resilient orthogonal signal-division multiplexing (D-OSDM), to provide a highly reliable communication environment in doubly spread channels for UWA communication. D...journal article 2015
- document
- Hu, Y. (author), Leus, G.J.T. (author) journal article 2015
- document
-
Farahmand, S. (author), Giannakis, G.B. (author), Leus, G.J.T. (author), Tian, Z. (author)Multi-target tracking is mainly challenged by the nonlinearity present in the measurement equation and the difficulty in fast and accurate data association. To overcome these challenges, the present paper introduces a grid-based model in which the state captures target signal strengths on a known spatial grid (TSSG). This model leads to linear...journal article 2014
- document
-
Xu, T. (author), Tang, Z. (author), Remis, R. (author), Leus, G. (author)OFDM suffers from inter-carrier interference (ICI) when the channel is time varying. This article seeks to quantify the amount of interference resulting from wideband OFDM channels, which are assumed to follow the multi-scale multi-lag (MSML) model. The MSML channel model results in full channel matrices both in the frequency and time domains....journal article 2012
- document
-
Ramezani, H. (author), Leus, G. (author)In this paper, we analyze the problem of acoustic ranging between sensor nodes in an underwater environment. The underwater medium is assumed to be composed of multiple isogradient sound speed profile (SSP) layers where in each layer the sound speed is linearly related to the depth. Furthermore, each sensor node is able to measure its depth and...journal article 2012
- document
-
Wang, Y. (author), Leus, G.J.T. (author)Low-complexity least-squares (LS) estimators based on time-of-arrival (TOA) or time-difference-of-arrival (TDOA) measurements have been developed to locate a target node with the help of anchors (nodes with known positions). They require to select a reference anchor in order to cancel nuisance parameters or relax stringent synchronization...journal article 2012
- document
-
Tang, Z. (author), Leus, G.J.T. (author)In this paper, we consider pilot-aided channel estimation for orthogonal frequency division multiplexing (OFDM) systems with a multiple-input multiple-output setup. The channel is time varying due to Doppler effects and can be approximated by an oversampled complex exponential basis expansion model. We use a best linear unbiased estimator (BLUE)...journal article 2011
- document
-
Godana, B. (author), Barroso, A. (author), Leus, G.J.T. (author)Radar is an attractive technology for long term monitoring of human movement as it operates remotely, can be placed behind walls and is able to monitor a large area depending on its operating parameters. A radar signal reflected off a moving person carries rich information on his or her activity pattern in the form of a set of Doppler frequency...journal article 2011
- document
- Xin, Y. (author), Wang, X. (author), Leus, G. (author), Yue, G. (author), Jiang, J. (author) journal article 2011
- document
-
Fang, K. (author), Rugini, L. (author), Leus, G. (author)Modern wireless communication systems require high transmission rates, giving rise to frequency selectivity due to multipath propagation. In addition, high-mobility terminals and scatterers induce Doppler shifts that introduce time selectivity. Therefore, advanced techniques are needed to accurately model the time- and frequency-selective (i.e.,...journal article 2010
- document
-
Wang, T. (author), Leus, G. (author), Huang, L. (author)Sensor positioning is an important task of location-aware wireless sensor networks. In most sensor positioning systems, sensors and beacons need to emit ranging signals to each other. Sensor ranging energy should be low to prolong system lifetime, but sufficiently high to fulfill prescribed accuracy requirements. This motivates us to investigate...journal article 2009
- document
-
Wang, Y. (author), Leus, G. (author), Van der Veen, A.J. (author)A complete detection, channel estimation, synchronization, and equalization scheme for a transmitted reference (TR) ultra-wideband (UWB) system is proposed in this paper. The scheme is based on a data model which admits a moderate data rate and takes both the interframe interference (IFI) and the intersymbol interference (ISI) into consideration...journal article 2009
- document
-
Fang, K. (author), Rugini, L. (author), Leus, G. (author)We propose low-complexity block turbo equalizers for orthogonal frequency-division multiplexing (OFDM) systems in time-varying channels. The presented work is based on a soft minimum mean-squared error (MMSE) block linear equalizer (BLE) that exploits the banded structure of the frequency-domain channel matrix, as well as a receiver window that...journal article 2008
- document
-
Tang, Z. (author), Leus, G. (author)In this paper, we present a single-carrier transceiver for rapidly time-varying channels, where the equalization step is implemented in the frequency domain. When the channel abides with both fast fading and severe inter-block interference, our equalizer relies on a band approximation of the frequencydomain channel matrix to maintain low...journal article 2008