Journal: IEEE Transactions on Wireless Communications

Abbreviation

IEEE trans. wirel. commun.

Publisher

IEEE

Journal Volumes

ISSN

1536-1276
1558-2248

Description

Filters

Reset filters

Search Results

Publications 1 - 10 of 24
  • Channel Charting in Real-World Coordinates With Distributed MIMO
    Item type: Journal Article
    Taner, Sueda; Palhares, Victoria; Studer, Christoph (2025)
    IEEE Transactions on Wireless Communications
    Channel charting is an emerging self-supervised method that maps channel-state information (CSI) to a low-dimensional latent space (the channel chart) that represents pseudo-positions of user equipments (UEs). While channel charts preserve local geometry, i.e., nearby UEs are nearby in the channel chart (and vice versa), the pseudo-positions are in arbitrary coordinates and global geometry is typically not preserved. In order to embed channel charts in real-world coordinates, we first propose a bilateration loss for distributed multiple-input multiple-output (D-MIMO) wireless systems in which only the access point (AP) positions are known. The idea behind this loss is to compare the received power at pairs of APs to determine whether a UE should be placed closer to one AP or the other in the channel chart. We then propose a line-of-sight (LoS) bounding-box loss that places the UE in a predefined LoS area of each AP that is estimated to have a LoS path to the UE. We demonstrate the efficacy of combining both of these loss functions with neural-network-based channel charting using ray-tracing-based and measurement-based channel vectors. Our proposed approach outperforms several baselines and maintains the self-supervised nature of channel charting as it neither relies on geometrical propagation models nor on any ground-truth UE position information.
  • Optimal power loading for multiple-input single-output OFDM systems with bit-level interleaving
    Item type: Conference Paper
    Mutti, Carlo; Dahlhaus, Dirk; Hunziker, Thomas (2006)
    IEEE Transactions on Wireless Communications
  • Joint Channel Estimation and Data Detection in Cell-Free Massive MU-MIMO Systems
    Item type: Journal Article
    Song, Haochuan; Goldstein, Tom; You, Xiaohu; et al. (2022)
    IEEE Transactions on Wireless Communications
    We propose a joint channel estimation and data detection (JED) algorithm for densely-populated cell-free massive multiuser (MU) multiple-input multiple-output (MIMO) systems, which reduces the channel training overhead caused by the presence of hundreds of simultaneously transmitting user equipments (UEs). Our algorithm iteratively solves a relaxed version of a maximum a-posteriori JED problem and simultaneously exploits the sparsity of cell-free massive MU-MIMO channels as well as the boundedness of QAM constellations. In order to improve the performance and convergence of the algorithm, we propose methods that permute the access point and UE indices to form so-called virtual cells, which leads to better initial solutions. We assess the performance of our algorithm in terms of root-mean-squared-symbol error, bit error rate, and mutual information, and we demonstrate that JED significantly reduces the pilot overhead compared to orthogonal training, which enables reliable communication with short packets to a large number of UEs.
  • Detection of Reactive Jamming in DSSS-based Wireless Communications
    Item type: Journal Article
    Spuhler, Michael; Giustiniano, Domenico; Lenders, Vincent; et al. (2014)
    IEEE Transactions on Wireless Communications
  • CSI-Based Multi-Antenna and Multi-Point Indoor Positioning Using Probability Fusion
    Item type: Journal Article
    Gönültaş, Emre; Lei, Eric; Langerman, Jack; et al. (2022)
    IEEE Transactions on Wireless Communications
    Channel state information (CSI)-based fingerprinting via neural networks (NNs) is a promising approach to enable accurate indoor and outdoor positioning of user equipments (UEs), even under challenging propagation conditions. In this paper, we propose a positioning pipeline for wireless LAN MIMO-OFDM systems which uses uplink CSI measurements obtained from one or more unsynchronized access points (APs). For each AP receiver, novel features are first extracted from the CSI that are robust to system impairments arising in real-world transceivers. These features are the inputs to a NN that extracts a probability map indicating the likelihood of a UE being at a given grid point. The NN output is then fused across multiple APs to provide a final position estimate. We provide experimental results with real-world indoor measurements under line-of-sight (LoS) and non-LoS propagation conditions for an 80MHz bandwidth IEEE 802.11ac system using a two-antenna transmit UE and two AP receivers each with four antennas. Our approach is shown to achieve centimeter-level median distance error, an order of magnitude improvement over a conventional baseline.
  • Simple ergodic and outage capacity expressions for correlated diversity ricean fading channels
    Item type: Journal Article
    Furrer, Simeon; Coronel, Pedro; Dahlhaus, Dirk (2006)
    IEEE Transactions on Wireless Communications
  • Throughput Analysis of Massive MIMO Uplink With Low-Resolution ADCs
    Item type: Journal Article
    Jacobsson, Sven; Durisi, Giuseppe; Coldrey, Mikael; et al. (2017)
    IEEE Transactions on Wireless Communications
    We investigate the uplink throughput achievable by a multiple-user (MU) massive multiple-input multiple-output (MIMO) system, in which the base station is equipped with a large number of low-resolution analog-to-digital converters (ADCs). Our focus is on the case where neither the transmitter nor the receiver have any a priori channel state information. This implies that the fading realizations have to be learned through pilot transmission followed by channel estimation at the receiver, based on coarsely quantized observations. We propose a novel channel estimator, based on Bussgang's decomposition, and a novel approximation to the rate achievable with finite-resolution ADCs, both for the case of finite-cardinality constellations and of Gaussian inputs, that is accurate for a broad range of system parameters. Through numerical results, we illustrate that, for the 1-bit quantized case, pilot-based channel estimation together with maximal-ratio combing, or zero-forcing detection enables reliable multi-user communication with high-order constellations, in spite of the severe nonlinearity introduced by the ADCs. Furthermore, we show that the rate achievable in the infinite-resolution (no quantization) case can be approached using ADCs with only a few bits of resolution. We finally investigate the robustness of low-ADC-resolution MU-MIMO uplink against receive power imbalances between the different users, caused for example by imperfect power control.
  • Performance of space-time modulation for a generalized time-varying rician channel model
    Item type: Journal Article
    Peel, C.B.; Swindlehurst, A.L. (2004)
    IEEE Transactions on Wireless Communications
  • Ultrawideband channel modeling on the basis of information-theoretic criteria
    Item type: Other Conference Item
    Schuster, Ulrich G.; Bölcskei, Helmut (2007)
    IEEE Transactions on Wireless Communications
  • Power allocation schemes for amplify-and-forward MIMO-OFDM relay links
    Item type: Journal Article
    Hammerström, Ingmar; Wittneben, Armin (2007)
    IEEE Transactions on Wireless Communications
Publications 1 - 10 of 24