| 1. |
- Valecha, Neharika, et al.
(författare)
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Angle estimation using mmWave RSS measurements with enhanced multipath information
- 2024
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Ingår i: 2024 IEEE Wireless Communications and Networking Conference.
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Konferensbidrag (refereegranskat)abstract
- mmWave communication has come up as the unexplored spectrum for 5G services. With new standards for 5G NR positioning, more off-the-shelf platforms and algorithms are needed to perform indoor positioning. An object can be accurately positioned in a room either by using an angle and a delay estimate or two angle estimates or three delay estimates. We propose an algorithm to jointly estimate the angle of arrival (AoA) and angle of departure (AoD), based only on the received signal strength (RSS). We use mm-FLEX, an experimentation platform developed by IMDEA Networks Institute that can perform real-time signal processing for experimental validation of our proposed algorithm. Codebook-based beampatterns are used with a uniquely placed multi-antenna array setup to enhance the reception of multipath components and we obtain an AoA estimate per receiver thereby overcoming the line-of-sight (LoS) limitation of RSS-based localization systems. We further validate the results from measurements by emulating the setup with a simple ray-tracing approach.
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| 2. |
- Bartoletti, Stefania, et al.
(författare)
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Positioning and Sensing for Vehicular Safety Applications in 5G and Beyond
- 2021
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Ingår i: IEEE Communications Magazine. - 0163-6804 .- 1558-1896. ; 59:11, s. 15-21
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Tidskriftsartikel (refereegranskat)abstract
- This article presents a shared vision among stakeholders across the value chain on the use of radio positioning and sensing for road safety in the 5G ecosystem. The key enabling technologies and architectural functionalities are explored, focusing on the extremely stringent localization and communication requirements. A case study for joint radar and communication using experimental data showcases the potential of the new enablers that are paving the way toward enhanced road safety in beyond 5G scenarios.
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| 3. |
- Bartoletti, Stefania, et al.
(författare)
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Positioning methods
- 2024
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Ingår i: Positioning and Location-based Analytics in 5G and Beyond. - 9781119911463 ; , s. 21-50
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter introduces the main positioning methods, starting from the state-of-the-art and following a statistical estimation perspective. This is followed by an in-depth treatment of radio positioning, first focusing on device-based positioning and then on device-free positioning. Finally, recent approaches based on artificial intelligence methods for positioning are detailed.
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| 4. |
- Fischione, Carlo, et al.
(författare)
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Guest Editorial Millimeter-Wave Networking
- 2019
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Ingår i: IEEE Journal on Selected Areas in Communications. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8716 .- 1558-0008. ; 37:12, s. 2649-2652
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Tidskriftsartikel (refereegranskat)
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| 5. |
- Fresia, Maria, et al.
(författare)
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Use case characterization, KPIs and preferred suitable frequency ranges for future 5G systems between 6 GHz and 100 GHz
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this deliverable use cases and KPIs of interest for mmMAGIC are characterized. Eight usecases suitable for 5G systems operating in the range 6-100GHz are identified in terms ofrequirements. In particular, the following use cases are analyzed: Media on demand; Cloudservices; Dense urban society with distributed crowds; Smart offices; Immersive 5G earlyexperience in targeting hot spots; 50+Mbps everywhere; Moving hot spots; Tactileinternet/video augmented robotic control and remote-robot manipulation surgery. For each ofthe use cases, the more critical KPIs are identified and the gap from the current technologyis also described.An analysis of frequency ranges for future 5G systems between 6 GHz and 100 GHz is reported. A frequency assessment study is conducted in order to compare the frequency ranges for the suitability of delivering key KPIs.
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| 6. |
- Keskin, Musa Furkan, 1988, et al.
(författare)
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Integrated Sensing and Communications with MIMO-OTFS: ISI/ICI Exploitation and Delay-Doppler Multiplexing
- 2024
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Ingår i: IEEE Transactions on Wireless Communications. - 1558-2248 .- 1536-1276. ; In Press
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Tidskriftsartikel (refereegranskat)abstract
- Orthogonal time frequency space (OTFS) is a promising alternative to orthogonal frequency-division multiplexing (OFDM) for high-mobility communications. We propose a novel multiple-input multiple-output (MIMO) integrated sensing and communication (ISAC) system based on OTFS modulation. We begin by deriving new sensing and communication signal models for the proposed MIMO-OTFS ISAC system that explicitly capture inter-symbol interference (ISI) and inter-carrier interference (ICI) effects. We then develop a generalized likelihood ratio test (GLRT) based multi-target detection and delay-Doppler-angle estimation algorithm for MIMO-OTFS radar sensing that can simultaneously mitigate and exploit ISI/ICI effects, to prevent target masking and surpass standard unambiguous detection limits in range/velocity. Moreover, considering two operational modes (discovery/track), we propose an adaptive MIMO-OTFS ISAC transmission strategy. For the discovery mode, we introduce the concept of delay-Doppler (DD) multiplexing, enabling omnidirectional probing of the environment and large virtual array at the OTFS radar receiver. For the track mode, we pursue a directional transmission approach and design an OTFS ISAC optimization algorithm in spatial and DD domains, seeking the optimal trade-off between radar signal-to-noise ratio (SNR) and achievable rate. Simulation results verify the effectiveness of the proposed sensing algorithm and reveal valuable insights into OTFS ISAC trade-offs under varying communication channel characteristics.
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| 7. |
- Shokri, Hossein
(författare)
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Fundamentals of Medium Access Control Design for Millimeter Wave Networks
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In current wireless communication systems, demands for extremely high data rates, along with spectrum scarcity at the microwave bands, make the millimeter wave (mmWave) band very appealing to provide these extremely high data rates even for a massive number of wireless devices. MmWave communications exhibit severe attenuation, vulnerability to obstacles (called blockage), and sparse-scattering environments. Moreover, mmWave signals have small wavelengths that allow the incorporation of many antenna elements at the current size of radio chips. This leads to high directivity gains both at the transmitter and at the receiver, directional communications, and, more importantly, possible noise-limited operations as opposed to microwave networks that are mostly interference-limited.These fundamental differences between mmWave networks and legacy communication technologies challenge the classical design constraints, objectives, and available degrees of freedom. The natural consequence is the necessity of revisiting most of the medium access control (MAC) layer design principles for mmWave networks, which have so far received less attention in the literature than physical layer and propagation issues. To address this important research gap, this thesis investigates the fundamental MAC layer performance metrics, including coverage, fairness, connection robustness, collision probability, per-link throughput, area spectral efficiency, and delay. The original analysis proposed in this thesis suggests novel insights as to the solutions for many MAC layer issues such as resource allocation, interference management, random access, mobility management, and synchronization in future mmWave networks.A first thread of the thesis focuses on the fundamental performance analysis and mathematical abstraction of mmWave wireless networks to characterize their differences from conventional wireless networks, i.e., high directivity, line-of-sight communications, and occurrence of deafness (misalignment between transmitters and receivers). A mathematical framework to investigate the impact of beam training (alignment) overhead on the throughput is established, which leads to identify a new alignment-throughput tradeoff in mmWave networks. A novel blockage model that captures the angular correlation of line-of-sight conditions using a new notion of "coherence angle" is proposed. The coverage and delay of directional cell discovery are evaluated, and an optimization approach to maximize long-term throughput of users with fairness guarantees is proposed. In addition, this thesis develops a tractable approach to derive the collision probability, as a function of density of the transmitters, transmission power, density and size of the obstacles, operating beamwidth, and sensitivity of the receiver, among the main parameters. The collision probability allows deriving closed-form expressions for the per-link and network throughput of mmWave networks, and thereby identifying that, contrary to mainstream belief, these networks may exhibit a non-negligible transitional behavior of interference from a noise-limited to an interference-limited regime.The second thread of the thesis builds on the previous fundamental performance analysis and modeling to establish new, efficient MAC protocols. The derived collision probability is used to evaluate per-link throughput, area spectral efficiency, and delay performance of common MAC protocols such as TDMA and slotted ALOHA, and to provide a fundamental comparison between pros and cons of contention-free and contention-based MAC protocols. The results suggest the use of on-demand interference management strategy for future mmWave cellular networks and collision-aware hybrid MAC protocols for mmWave ad hoc networks to reliably deliver messages without sacrificing throughput and delay performance. Moreover, the transitional behavior, together with significant mismatch between transmission rates of control and data messages, imposes the development of new hybrid proactive and reactive control plane architecture. This thesis identifies the prolonged backoff time problem, which happens in mmWave networks due to blockage and deafness, and proposes a new collision notification signal to solve this problem. Motivated by the significant mismatch between coverage of the control and data planes along with delay analysis of directional cell search, a novel two-step synchronization procedure is proposed for mmWave cellular networks. Also, the impact of relaying and multi-hop communication to provide reliable mmWave connections, to alleviate frequent handovers, and to reduce the beam training overhead is investigated.The investigations of this thesis aim to demystify MAC layer performance of mmWave networks and to show the availability of many new degrees of freedom to improve the network performance, e.g., in terms of area spectral efficiency, energy efficiency, robustness, delay, coverage, and uniform quality of service provisioning. The results reveal many special behaviors of mmWave networks that are largely ignored in design approach of the current mmWave networks. Given that the standardization of mmWave wireless cellular networks has not started as yet, and that existing standards of mmWave ad hoc networks are highly sub-optimal, the results of this thesis will provide fundamental design guidelines that have the potential to be very useful for future mmWave standardizations.
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| 8. |
- Subramanyam Thoota, Sai, et al.
(författare)
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Site-specific millimeter-wave compressive channel estimation algorithms with hybrid MIMO architectures
- 2021
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Ingår i: ITU Journal on Future and Evolving Technologies. - : International Telecommunication Union. - 2616-8375. ; 2:4
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present and compare three novel model-cum-data-driven channel estimation procedures in a millimeter-wave Multi-Input Multi-Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) wireless communication system. The transceivers employ a hybrid analog-digital architecture. We adapt techniques from a wide range of signal processing methods, such as detection and estimation theories, compressed sensing, and Bayesian inference, to learn the unknown virtual beamspace domain dictionary, as well as the delay-and-beamspace sparse channel. We train the model-based algorithms with a site-specific training dataset generated using a realistic ray tracing-based wireless channel simulation tool. We assess the performance of the proposed channel estimation algorithms with the same site's test data. We benchmark the performance of our novel procedures in terms of normalized mean squared error against an existing fast greedy method and empirically show that model-based approaches combined with data-driven customization unanimously outperform the state-of-the-art techniques by a large margin. The proposed algorithms were selected as the top three solutions in the "ML5G-PHY Channel Estimation Global Challenge 2020" organized by the International Telecommunication Union.
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| 9. |
- Widmer, Joerg, et al.
(författare)
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Enablers toward 6G positioning and sensing
- 2024
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Ingår i: Positioning and Location-based Analytics in 5G and Beyond. - 9781119911463 ; , s. 75-97
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter provides the reader with an overview of three major trends toward 6G, namely integrated sensing and communication, the ability to control radio wave propagation in the environment thanks to reconfigurable intelligent surfaces, and advances in model-based and model-free signal processing. This list of trends is by no means exhaustive, but only aims to highlight the tremendous potential for research and innovation toward 6G positioning.
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