References of "Ottersten, Björn 50002797"
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See detailSequential Resource Distribution Technique for Multi-User OFDM-SWIPT based Cooperative Networks
Gautam, Sumit UL; Lagunas, Eva UL; Chatzinotas, Symeon UL et al

Scientific Conference (2018, December)

In this paper, we investigate resource allocation and relay selection in a dual-hop orthogonal frequency division multiplexing (OFDM)-based multi-user network where amplify-and-forward (AF) enabled relays ... [more ▼]

In this paper, we investigate resource allocation and relay selection in a dual-hop orthogonal frequency division multiplexing (OFDM)-based multi-user network where amplify-and-forward (AF) enabled relays facilitate simultaneous wireless information and power transfer (SWIPT) to the end-users. In this context, we address an optimization problem to maximize the end-users’ sum-rate subjected to transmit power and harvested energy constraints. Furthermore, the problem is formulated for both time-switching (TS) and power-splitting (PS) SWIPT schemes.We aim at optimizing the users’ SWIPT splitting factors as well as sub-carrier–destination assignment, sub-carrier pairing, and relay–destination coupling metrics. This kind of joint evaluation is combinatorial in nature with non-linear structure involving mixed-integer programming. In this vein, we propose a sub-optimal low complex sequential resource distribution (SRD) method to solve the aforementioned problem. The performance of the proposed SRD technique is compared with a semi-random resource allocation and relay selection approach. Simulation results reveal the benefits of the proposed design under several parameter values with various operating conditions to illustrate the efficiency of SWIPT schemes for the proposed techniques. [less ▲]

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See detailPower and Load Optimization in Interference-Coupled Non-Orthogonal Multiple Access Networks
Lei, Lei UL; You, Lei; Yang, Yang UL et al

in IEEE Global Communications Conference (GLOBECOM) 2018 (2018, December)

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See detailPowerMinimizer Symbol-Level Precoding: A Closed-Form Sub-Optimal Solution
Haqiqatnejad, Alireza UL; Kayhan, Farbod UL; Ottersten, Björn UL

in IEEE Signal Processing Letters (2018), 25(11), 1730-1734

In this letter, we study the optimal solution of multiuser symbol-level precoding (SLP) for minimization of the total transmit power under given signal-to-interference-plus noise ratio (SINR) constraints ... [more ▼]

In this letter, we study the optimal solution of multiuser symbol-level precoding (SLP) for minimization of the total transmit power under given signal-to-interference-plus noise ratio (SINR) constraints. Adopting the distance preserving constructive interference regions (DPCIR), we first derive a simplified reformulation of the problem. Then, we analyze the structure of the optimal solution using the Karush-Kuhn-Tucker (KKT) optimality conditions. This leads us to obtain a closed-form sub-optimal SLP solution (CF-SLP) for the original problem. Meanwhile, we obtain the necessary and sufficient condition under which the power minimizer SLP is equivalent to the conventional zero-forcing beamforming (ZFBF). Simulation results show that CF-SLP provides significant gains over ZFBF, while performing quite close to the optimal SLP in scenarios with rather small number of users. The results further indicate that the CF-SLP method has a reduction of order 1000 in computational time compared to the optimal solution. [less ▲]

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See detailSuccessive convex approximation algorithms for sparse signal estimation with nonconvex regularizations
Yang, Yang UL; Pesavento, Marius; Chatzinotas, Symeon UL et al

in IEEE Journal of Selected Topics in Signal Processing (2018)

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See detailParallel and hybrid soft-thresholding algorithms with line search for sparse nonlinear regression
Yang, Yang UL; Pesavento, Marius; Chatzinotas, Symeon UL et al

in Proc. 26th European Signal Processing Conference (2018, September)

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See detailSymbol-Level Precoding Design for Max-Min SINR in Multiuser MISO Broadcast Channels
Haqiqatnejad, Alireza UL; Kayhan, Farbod UL; Ottersten, Björn UL

in International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), Kalamata 25-28 June 2018 (2018, August 27)

In this paper, we address the symbol level precoding (SLP) design problem under max-min SINR criterion in the downlink of multiuser multiple-input single-output (MISO) channels. First, we show that the ... [more ▼]

In this paper, we address the symbol level precoding (SLP) design problem under max-min SINR criterion in the downlink of multiuser multiple-input single-output (MISO) channels. First, we show that the distance preserving constructive interference regions (DPCIR) are always polyhedral angles (shifted pointed cones) for any given constellation point with unbounded decision region. Then we prove that any signal in a given unbounded DPCIR has a norm larger than the norm of the corresponding vertex if and only if the convex hull of the constellation contains the origin. Using these properties, we show that the power of the noiseless received signal lying on an unbounded DPCIR is an strictly increasing function of two parameters. This allows us to reformulate the originally non-convex SLP max-min SINR as a convex optimization problem. We discuss the loss due to our proposed convex reformulation and provide some simulation results. [less ▲]

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See detailResource Allocation and Relay Selection for Multi-User OFDM-Based Cooperative Networks with SWIPT
Gautam, Sumit UL; Lagunas, Eva UL; Chatzinotas, Symeon UL et al

Scientific Conference (2018, August)

In this paper, we investigate resource allocation and relay selection in a two-hop relay-assisted multi-user network, where the end users support Simultaneous Wireless Information and Power Transfer ... [more ▼]

In this paper, we investigate resource allocation and relay selection in a two-hop relay-assisted multi-user network, where the end users support Simultaneous Wireless Information and Power Transfer (SWIPT). In particular, we consider single source assisted by a set of spatially distributed relays able to amplify-and-forward orthogonal frequency division multiplexing (OFDM) signals carrying both data and power at the same time. The users are assumed to implement a power splitting technique where the received signal is orthogonally split in two streams of different power levels, where one signal stream is sent to the power harvesting module while the other is converted to baseband for information decoding. We aim at optimizing the users’ power splitting ratios as well as the relay, carrier and power assignment so that the end-users’ sum-rate is maximized subject to transmitted and harvested power constraints. Such joint optimization is combinatorial in nature with a non-convex structure. Therefore, we present a sub-optimal low complex solution based on the harmonic mean of the two-hop relay channel coefficients. Simulation results reveal that the proposed algorithm provides significant performance gains in comparison with a semi-random resource allocation and relay selection approach. [less ▲]

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See detailResource Optimization With Load Coupling in Multi-Cell NOMA
You, Lei; Yuan, Di; Lei, Lei UL et al

in IEEE Transactions on Wireless Communications (2018)

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See detailBlock Circulant Decomposition of Cross-Correlation Matrix for Transmit MIMO Beamforming
Hammes, Christian UL; Shankar, Bhavani UL; Ottersten, Björn UL

Poster (2018, July)

This paper deals with the design of transmit probing signal under the trade-off between good target discrimination (low cross-correlation beam pattern) and beam pattern design (desired auto-correlation ... [more ▼]

This paper deals with the design of transmit probing signal under the trade-off between good target discrimination (low cross-correlation beam pattern) and beam pattern design (desired auto-correlation beam pattern) in a Multiple-Input- Multiple-Output (MIMO) radar configuration. The quartic optimization problem, with a finite alphabet constraint on the probing signal and using Quadrature Phase Shift Keying (QPSK) in a multiplexed antenna system, is solved through a Fourier series approximation of the desired beam pattern by exploiting a block circulant property of the transmit signal matrix. The mean square error between an ideal and the proposed crosscorrelation beam pattern is -35 dB enhancing the attractiveness of the proposed approach. [less ▲]

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See detailSuccessive convex approximation algorithms for sparse signal estimation with nonconvex regularizations
Yang, Yang UL; Pesavento, Marius; Chatzinotas, Symeon UL et al

in Proc. The 10th IEEE Sensor Array and Multichannel Signal Processing Workshop (2018, July)

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See detailHighway Network Block with Gates Constraints for Training Very Deep Networks
Oyedotun, Oyebade UL; Shabayek, Abd El Rahman UL; Aouada, Djamila UL et al

in 2018 IEEE International Conference on Computer Vision and Pattern Recognition Workshop, June 18-22, 2018 (2018, June 19)

In this paper, we propose to reformulate the learning of the highway network block to realize both early optimization and improved generalization of very deep networks while preserving the network depth ... [more ▼]

In this paper, we propose to reformulate the learning of the highway network block to realize both early optimization and improved generalization of very deep networks while preserving the network depth. Gate constraints are duly employed to improve optimization, latent representations and parameterization usage in order to efficiently learn hierarchical feature transformations which are crucial for the success of any deep network. One of the earliest very deep models with over 30 layers that was successfully trained relied on highway network blocks. Although, highway blocks suffice for alleviating optimization problem via improved information flow, we show for the first time that further in training such highway blocks may result into learning mostly untransformed features and therefore a reduction in the effective depth of the model; this could negatively impact model generalization performance. Using the proposed approach, 15-layer and 20-layer models are successfully trained with one gate and a 32-layer model using three gates. This leads to a drastic reduction of model parameters as compared to the original highway network. Extensive experiments on CIFAR-10, CIFAR-100, Fashion-MNIST and USPS datasets are performed to validate the effectiveness of the proposed approach. Particularly, we outperform the original highway network and many state-ofthe- art results. To the best our knowledge, on the Fashion-MNIST and USPS datasets, the achieved results are the best reported in literature. [less ▲]

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See detailPose Encoding for Robust Skeleton-Based Action Recognition
Demisse, Girum UL; Papadopoulos, Konstantinos UL; Aouada, Djamila UL et al

in CVPRW: Visual Understanding of Humans in Crowd Scene, Salt Lake City, Utah, June 18-22, 2018 (2018, June 18)

Some of the main challenges in skeleton-based action recognition systems are redundant and noisy pose transformations. Earlier works in skeleton-based action recognition explored different approaches for ... [more ▼]

Some of the main challenges in skeleton-based action recognition systems are redundant and noisy pose transformations. Earlier works in skeleton-based action recognition explored different approaches for filtering linear noise transformations, but neglect to address potential nonlinear transformations. In this paper, we present an unsupervised learning approach for estimating nonlinear noise transformations in pose estimates. Our approach starts by decoupling linear and nonlinear noise transformations. While the linear transformations are modelled explicitly the nonlinear transformations are learned from data. Subsequently, we use an autoencoder with L2-norm reconstruction error and show that it indeed does capture nonlinear noise transformations, and recover a denoised pose estimate which in turn improves performance significantly. We validate our approach on a publicly available dataset, NW-UCLA. [less ▲]

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See detailNOMA Aided Interference Management for Full-Duplex Self-Backhauling HetNets
Lei, Lei UL; Lagunas, Eva UL; Chatzinotas, Symeon UL et al

in IEEE Communications Letters (2018), 22(8), 1696-1699

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See detailCarrier Allocation for 5G Integrated Satellite-Terrestrial Backhaul Networks
Lagunas, Eva UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in International Conference on Communications (ICT), Saint-Malo, France, June 2018. (2018, June)

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See detailComputationally and Energy Efficient Symbol-Level Precoding Communications Demonstrator
Krivochiza, Jevgenij UL; Merlano Duncan, Juan Carlos UL; Andrenacci, Stefano UL et al

in Physical Communication (2018), 28

We present a precoded multi-user communication test-bed to demonstrate forward link interference mitigation techniques in a multi-beam satellite system scenario, which will enable a full frequency reuse ... [more ▼]

We present a precoded multi-user communication test-bed to demonstrate forward link interference mitigation techniques in a multi-beam satellite system scenario, which will enable a full frequency reuse scheme. The developed test-bed provides an end-to-end precoding demonstration, which includes a transmitter, a multi-beam satellite channel emulator and user receivers. Each of these parts can be reconfigured accordingly to the desired test scenario. Precoded communications allow full frequency reuse in multiple-input multiple-output (MIMO) channel environments, where several coordinated antennas simultaneously transmit to a number of independent receivers. The developed real-time transmission test-bed assist in demonstrating, designing and benchmarking of the new Symbol-Level Precoding (SLP) techniques, where the data information is used, along with the channel state information, in order to exploit the multi-user interference and transform it into the useful power at the receiver side. The demonstrated SLP technique is designed in order to be computationally efficient, and can be generalized to others multi-channel interference scenarios. [less ▲]

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See detailKey-Skeleton Based Feedback Tool for Assisting Physical Activity
Baptista, Renato UL; Ghorbel, Enjie UL; Shabayek, Abd El Rahman UL et al

in 2018 Zooming Innovation in Consumer Electronics International Conference (ZINC), 30-31 May 2018 (2018, May 31)

This paper presents an intuitive feedback tool able to implicitly guide motion with respect to a reference movement. Such a tool is important in multiple applications requiring assisting physical ... [more ▼]

This paper presents an intuitive feedback tool able to implicitly guide motion with respect to a reference movement. Such a tool is important in multiple applications requiring assisting physical activities as in sports or rehabilitation. Our proposed approach is based on detecting key skeleton frames from a reference sequence of skeletons. The feedback is based on the 3D geometry analysis of the skeletons by taking into account the key-skeletons. Finally, the feedback is illustrated by a color-coded tool, which reflects the motion accuracy. [less ▲]

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See detailReduced complexity satellite broadcast receiver with interference mitigation in correlated noise
Abu Shaban, Zohair UL; Mehrpouyan, Hani UL; Shankar, Bhavani UL et al

in International Journal of Satellite Communications and Networking (2018), 36(5),

ry The recent commercial trends towards using smaller dish antennas for satellite receivers and the growing density of broadcasting satellites necessitate the application of robust adjacent satellite ... [more ▼]

ry The recent commercial trends towards using smaller dish antennas for satellite receivers and the growing density of broadcasting satellites necessitate the application of robust adjacent satellite interference cancellation schemes. This orbital density growth along with the wider beamwidth of a smaller dish have imposed an overloaded scenario at the satellite receiver, where the number of transmitting satellites exceeds the number of receiving elements at the dish antenna. To ensure successful operation in this practical scenario, we propose a satellite receiver that enhances signal detection from the desired satellite by mitigating the interference from neighboring satellites. Towards this objective, we propose an enhanced list‐based group‐wise search detection (E‐LGSD) receiver under the assumption of spatially correlated additive noise. To further enhance detection performance, the proposed satellite receiver utilizes a newly designed whitening filter to remove the spatial correlation among the noise parameters, while also applying a preprocessor that maximizes the signal‐to‐interference‐plus‐noise ratio. We exploit the structure of this filter and propose a reduced complexity LGSD (RC‐LGSD) receiver. Extensive simulations under practical scenarios show that the proposed receiver enhances the performance of satellite broadcast systems in the presence of adjacent satellite interference compared with existing methods. Also, under pointing error, RC‐LGSD exhibits similar behavior to that of the optimum receiver. [less ▲]

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See detailEfficient Resource Optimization in Wireless Networks: A Deep-Learning Assisted Approach
Lei, Lei UL; You, Lei; Yuan, Di et al

in 2018 INFORMS Telecommunications Conference (2018, May)

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See detailLatency Minimization for Content Delivery Networks with Wireless Edge Caching
Vu, Thang Xuan UL; Lei, Lei UL; Vuppala, Satyanarayana et al

in 2018 IEEE International Conference on Communications (ICC) (2018, May)

Detailed reference viewed: 13 (0 UL)