| 1. |
- He, Jiguang, et al.
(författare)
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Large Intelligent Surface for Positioning in Millimeter Wave MIMO Systems
- 2020
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Ingår i: IEEE Vehicular Technology Conference. - 1550-2252. ; 2020-May
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Konferensbidrag (refereegranskat)abstract
- Millimeter-wave (mmWave) multiple-input multiple-output (MIMO) system for the fifth generation (5G) cellular communications can also enable single-anchor positioning and object tracking due to its large bandwidth and inherently high angular resolution. In this paper, we introduce the newly invented concept, large intelligent surface (LIS), to mmWave positioning systems, study the theoretical performance bounds (i.e., Cramér-Rao lower bounds) for positioning, and evaluate the impact of the number of LIS elements and the value of phase shifters on the position estimation accuracy compared to the conventional scheme with one direct link and one non-line-of-sight path. It is verified that better performance can be achieved with a LIS from the theoretical analyses and numerical study.
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| 2. |
- Javidsharifi, Mahshid, et al.
(författare)
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PV-Powered Base Stations Equipped by UAVs in Urban Areas
- 2022
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Ingår i: 2022 IEEE 96th Vehicular Technology Conference, VTC 2022-Fall 2022 - Proceedings. - 1550-2252. - 9781665454681 ; 2022-September
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Konferensbidrag (refereegranskat)abstract
- Recently, the application of unmanned aerial vehicles (UAVs) to support the base stations in cellular telecommunication networks attracts attentions. UAV-assisted base stations can provide the extra users' demand in extreme and/ or unpredictable situations such as Olympic Games to avoid extra cost of installing ground base stations. In this paper, a PV-battery power system is presented to supply UAV-assisted base stations in cellular telecommunication networks in urban areas to prevent environmental issues as well as to reduce the cost of fulfilling the energy demand. First, the energy consumption profile of the batteries of UAVs is estimated. Afterwards, the impact of the PV system sizing and battery capacity are studied based on sensitivity analysis.
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| 3. |
- Kletsov, Andrey, et al.
(författare)
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A General Simulation Framework for Radiative Wireless Power Transfer Systems Based On Phased-Array Transmitters
- 2023
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Ingår i: IEEE Vehicular Technology Conference. - 1550-2252. ; 2023-June
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Konferensbidrag (refereegranskat)abstract
- Radiative wireless power transfer (WPT) is an emerging technology for charging moving objects (e.g., vehicles) or static user terminals (e.g., mobile handsets). The most popular radiative WPT techniques employ transmitter (TX) and receiver (RX) phased arrays with dynamic beamforming functionalities. In this paper, we present a simulation approach capable of accurately estimating main WPT characteristics such as received power and power transfer efficiency. The method employs the equivalence principle to approximate TX and RX antenna apertures during the charging process, whereas antenna coupling is computed using the reaction concept. We demonstrate several multi-RX charging examples for different amplitude-only TX autofocusing algorithms. The discussion is complemented by an RX rectifier performance consideration.
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| 4. |
- Koirala, Remun, et al.
(författare)
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Direction Aided Multipath Channel Estimation for Millimeter Wave Systems
- 2021
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Ingår i: IEEE Vehicular Technology Conference. - 1550-2252. ; 2021-April
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Konferensbidrag (refereegranskat)abstract
- In this paper, we present a low-latency direction assisted channel estimation algorithm suitable for millimeter wave (mm-Wave) systems. First, during the beam training procedure, we perform angle of departure (AoD) and angle of arrival (AoA) measurements with their corresponding variances and based on them, we design both downlink and uplink beams. We then perform signal measurements with these beams and accordingly design the sensing matrix, while also iteratively refining the angle estimation and the beams for the next measurements accordingly. Finally, exploiting both the sparseness and the intrinsic geometric nature of the mm-Wave channel, we apply compressive sensing tools so as to complete the estimation procedure. Simulations show that the corresponding estimation error decreases rapidly in comparison with other conventional approaches.
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| 5. |
- Lu, Yi, et al.
(författare)
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Joint RIS Calibration and Multi-User Positioning
- 2022
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Ingår i: IEEE Vehicular Technology Conference. - 1550-2252. ; 2022-September
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Konferensbidrag (refereegranskat)abstract
- Reconfigurable intelligent surfaces (RISs) are expected to be a key component enabling the mobile network evolution towards a flexible and intelligent 6G wireless platform. In most of the research works so far, RIS has been treated as a passive base station (BS) with a known state, in terms of its location and orientation, to boost the communication and/or terminal positioning performance. However, such performance gains cannot be guaranteed anymore when the RIS state is not perfectly known. In this paper, by taking the RIS state uncertainty into account, we formulate and study the performance of a joint RIS calibration and user positioning (JrCUP) scheme. From the Fisher information perspective, we formulate the JrCUP problem in a network-centric single-input multiple-output (SIMO) scenario with a single BS, and derive the analytical lower bound for the states of both user and RIS. We also demonstrate the geometric impact of different user locations on the JrCUP performance while also characterizing the performance under different RIS sizes. Finally, the study is extended to a multiuser scenario, shown to further improve the state estimation performance.
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| 6. |
- Maham, Behrouz, et al.
(författare)
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Performance Analysis of Millimeter Wave CoMP Networks under Blockage
- 2021
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Ingår i: IEEE Vehicular Technology Conference. - 1550-2252. ; 2021-April
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Konferensbidrag (refereegranskat)abstract
- In this paper, a coordinated multi-point (CoMP) based mmWave communications operating over access links impaired by blockage is considered. By assuming realistic assumptions such as line-of-sight and non-line-of-sight channel components, fading, and random blockage, we propose a tractable analytical framework for mmWave communications. Moreover, the performance of the CoMP-based mmWave communication is evaluated by deriving the distribution of the received signal and presenting closed form expression for outage probability. Simulation results show the correctness of the analytical results and impact of blockage on the reliability of the mmWave communications.
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| 7. |
- Mao, Yadong, et al.
(författare)
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Decentralized Training of 3D Lane Detection with Automatic Labeling Using HD Maps
- 2023
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Ingår i: IEEE Vehicular Technology Conference. - 1550-2252. ; 2023-June
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Konferensbidrag (refereegranskat)abstract
- To have competent 3D lane detection for real-world driving, a massive amount of data from all over the world is needed, but data collection and manual annotation are costly and time-consuming. The diversity of data collected by developmental cars might still be limited compared to the data collected by a large fleet of customer cars. Federated learning enables training models on edge without transferring data out of devices. However, training supervised learning tasks at the edge is directly tied to having access to high-quality labels, which is limited at the edge. In this paper, we propose a fully automatic method to generate 3D lane labels at the edge using a pre-recorded HD map to enable the federated training of the 3D lane detection model. As a reference, a semi-automatic method is applied for creating a 3D-lane dataset used as ground truth. Our experimental results show that the model can achieve comparable performance when training on the same dataset in both a centralized and a decentralized manner. And the models trained on semi-automatic labeled datasets slightly outperform those trained on fully-automatically labeled datasets. This study shows that a well-performing 3D lane detection model can be trained in a supervised and fully decentralized manner, and most importantly, data privacy at the edge is guaranteed.
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| 8. |
- Muneer, Sidra, et al.
(författare)
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System Design and Performance for Antenna Reservation in Massive MIMO
- 2022
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Ingår i: 2022 IEEE 96th Vehicular Technology Conference, VTC 2022-Fall 2022 - Proceedings. - 1550-2252. - 9781665454681 ; 2022-September
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Konferensbidrag (refereegranskat)abstract
- Peak to average power (PAPR) reduction of OFDM signals is critical in order to improve power amplifier (PA) efficiency in base stations. For massive MIMO, the complexity of these methods can become a real bottleneck in implementing low power digital signal processing chains. In this work, we consider an antenna reservation technique, which uses a low complexity clipping method to reduce signal peaks and leverages the benefit of massive antennas, by reserving a subset of antennas in order to compensate for the clipping distortion. Reserving antennas on the other hand reduces the potential array gain in the massive MIMO system, complicating the application of antenna reservation. This work explores various design space parameters in antenna reservation such as number of reserved antennas, amount of peak reduction and clipping methods. We investigate the impact of these parameters on the error vector magnitude at the user and on the adjacent channel power ratio at both transmitter and user positions. Our results enable a deeper understanding of antenna reservation as a low complexity PAPR reduction method in massive MIMO systems.
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| 9. |
- Pereira, Andreia, et al.
(författare)
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A Low Complexity Sequential Resource Allocation for Panel-Based LIS Surfaces
- 2022
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Ingår i: 2022 IEEE 95th Vehicular Technology Conference - Spring, VTC 2022-Spring - Proceedings. - 1550-2252. - 9781665482431 ; 2022-June
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Konferensbidrag (refereegranskat)abstract
- Large intelligent surfaces (LISs) is an evolution of massive MIMO systems allowing for huge capacity gains. To reduce implementation complexity, it is convenient to implement the LIS using panels that are either activated or deactivated, and associated to terminals according to their propagation characteristics to the panels. The associated spatial resource allocation to maximise the terminals', as well as the overall, bit rates can lead to complex optimisation problems.In this paper we consider resource allocation for panel-based LIS surfaces. We present an iterative sequential algorithm for determining the set of active panels and the respective panel-terminal association for the maximisation of the minimum terminal rate. Our algorithm is decentralised and has low complexity. Moreover, it approaches the performance of much more complex, quasi-optimum algorithms.
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| 10. |
- Rahal, Moustafa, et al.
(författare)
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Constrained RIS Phase Profile Optimization and Time Sharing for Near-field Localization
- 2022
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Ingår i: IEEE Vehicular Technology Conference. - 1550-2252. ; 2022-June
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Konferensbidrag (refereegranskat)abstract
- The rising concept of reconfigurable intelligent surface (RIS) has promising potential for Beyond 5G localization applications. We herein investigate different phase profile designs at a reflective RIS, which enable non-line-of-sight positioning in nearfield from downlink single antenna transmissions. We first derive the closed-form expressions of the corresponding Fisher information matrix (FIM) and position error bound (PEB). Accordingly, we then propose a new localization-optimal phase profile design, assuming prior knowledge of the user equipment location. Numerical simulations in a canonical scenario show that our proposal outperforms conventional RIS random and directional beam codebook designs in terms of PEB. We also illustrate the four beams allocated at the RIS (i.e., one directional beam, along with its derivatives with respect to space dimensions) and show how their relative weights according to the optimal solution can be practically implemented through time sharing (i.e., considering feasible beams sequentially).
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