| 1. |
- Abu-Shaban, Z., et al.
(författare)
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Near-field Localization with a Reconfigurable Intelligent Surface Acting as Lens
- 2021
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Ingår i: IEEE International Conference on Communications. - 1550-3607. ; June 2021
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Konferensbidrag (refereegranskat)abstract
- Exploiting wavefront curvature enables localization with limited infrastructure and hardware complexity. With the introduction of reconfigurable intelligent surfaces (RISs), new opportunities arise, in particular when the RIS is functioning as a lens receiver. We investigate the localization of a transmitter using a RIS-based lens in close proximity to a single receive antenna element attached to reception radio frequency chain. We perform a Fisher information analysis, evaluate the impact of different lens configurations, and propose a two-stage localization algorithm. Our results indicate that positional beamforming can lead to better performance when a priori location information is available, while random beamforming is preferred when a priori information is lacking. Our simulation results for a moderate size lens operating at 28 GHz showcased that decimeter-level accuracy can be attained within 3 meters to the lens.
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| 2. |
- Alegria, Juan Vidal, et al.
(författare)
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Enabling Decentralized Computation of the WAX Decomposition
- 2022
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Ingår i: ICC 2022 - IEEE International Conference on Communications. - 1550-3607. ; 2022
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Konferensbidrag (refereegranskat)abstract
- As the number of antennas scales up, research efforts have been directed towards finding decentralized receiver solutions for multi-antenna architectures. In a recent paper, a novel matrix decomposition - the WAX decomposition - was proposed, which has direct bearing on characterizing the level of decentralization that is possible if the complexity of the decentralized processing is limited. However, the available work on WAX decomposition has left some gaps in determining how one of its basis matrices has to be defined. In this paper we present a number of constructions for effectively defining said basis matrix, and we show how they facilitate decentralized calculation of the WAX decomposition itself for applying information-lossless processing in architectures with an arbitrary level of decentralization. Thereby, taking a major step towards realizing decentralized receiver solution for large scale antenna systems.
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| 3. |
- Clazzer, Federico, et al.
(författare)
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Error Floor Analysis of Irregular Repetition ALOHA
- 2022
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Ingår i: IEEE International Conference on Communications. - 1550-3607. ; 2022-May, s. 4007-4012
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Konferensbidrag (refereegranskat)abstract
- With the rapid expansion of the Internet of Things, the efficient sharing of the wireless medium by a large amount of simple transmitters is becoming essential. Scheduling-based solutions are inefficient for this setting, where small data units are broadcast sporadically by terminals that most of the time are idle. Modern random access has embraced the challenge and provides suitable slot-synchronous and asynchronous multiple access solutions based on replicating the packets and exploiting successive interference cancellation (SIC) at the receiver. In this work, we focus on asynchronous modern random access. Specifically, we derive an analytical approximation of the performance of irregular repetition ALOHA (IRA) in the so-called error floor region. Numerical results show the tightness of the derived approximation under various scenarios.
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| 4. |
- Ge, Yu, 1995, et al.
(författare)
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Iterated Posterior Linearization PMB Filter for 5G SLAM
- 2022
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Ingår i: IEEE International Conference on Communications. - 1550-3607. ; 2022-May, s. 877-882
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Konferensbidrag (refereegranskat)abstract
- 5G millimeter wave (mmWave) signals have inherent geometric connections to the propagation channel and the propagation environment. Thus, they can be used to jointly localize the receiver and map the propagation environment, which is termed as simultaneous localization and mapping (SLAM). One of the most important tasks in the 5G SLAM is to deal with the nonlinearity of the measurement model. To solve this problem, existing 5G SLAM approaches rely on sigma-point or extended Kalman filters, linearizing the measurement function with respect to the prior probability density function (PDF). In this paper, we study the linearization of the measurement function with respect to the posterior PDF, and implement the iterated posterior linearization filter into the Poisson multi-Bernoulli SLAM filter. Simulation results demonstrate the accuracy and precision improvements of the resulting SLAM filter.
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| 5. |
- Ghazalian, Reza, et al.
(författare)
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RIS Position and Orientation Estimation via Multi-Carrier Transmissions and Multiple Receivers
- 2023
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Ingår i: IEEE International Conference on Communications. - 1550-3607. ; 2023-May, s. 2915-2920
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Konferensbidrag (refereegranskat)abstract
- Reconfigurable intelligent surfaces (RISs) are considered as an enabling technology for the upcoming sixth generation of wireless systems, exhibiting significant potential for radio localization and sensing. An RIS is usually treated as an anchor point with known position and orientation when deployed to offer user localization. However, it can also be attached to a user to enable its localization in a semi-passive manner. In this paper, we consider a static user equipped with an RIS and study the RIS localization problem (i.e., joint three-dimensional position and orientation estimation), when operating in a system comprising a single-antenna transmitter and multiple synchronized single-antenna receivers with known locations. We present a multi-stage estimator using time-of-arrival and spatial frequency measurements, and derive the Cramér-Rao lower bounds for the estimated parameters to validate the estimator's performance. Our simulation results demonstrate the efficiency of the proposed RIS state estimation approach under various system operation parameters.
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| 6. |
- Jiang, Fan, 1987-, et al.
(författare)
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Low-complexity Channel Estimation and Localization with Random Beamspace Observations
- 2023
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Ingår i: ICC 2023 - IEEE International Conference on Communications. - Piscataway, NJ : IEEE. - 9781538674628 ; 2023-May, s. 5985-5990
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Konferensbidrag (refereegranskat)abstract
- We investigate the problem of low-complexity, high-dimensional channel estimation with beamspace observations, for the purpose of localization. Existing work on beamspace ESPRIT (estimation of signal parameters via rotational invariance technique) approaches requires either a shift-invariance structure of the transformation matrix, or a full-column rank condition. We extend these beamspace ESPRIT methods to a case when neither of these conditions is satisfied, by exploiting the full-row rank of the transformation matrix. We first develop a tensor decomposition-based approach, and further design a matrix-based ESPRIT method to achieve auto-pairing of the channel parameters, with reduced complexity. Numerical simulations show that the proposed methods work in the challenging scenario, and the matrix-based ESPRIT approach achieves better performance than the tensor ESPRIT method. © 2023 IEEE
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| 7. |
- Keykhosravi, Kamran, 1990, et al.
(författare)
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RIS-Enabled Self-Localization: Leveraging Controllable Reflections With Zero Access Points
- 2022
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Ingår i: IEEE International Conference on Communications. - 1550-3607. ; 2022-May, s. 2852-2857
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Konferensbidrag (refereegranskat)abstract
- Reconfigurable intelligent surfaces (RISs) are one of the most promising technological enablers of the next (6th) generation of wireless systems. In this paper, we introduce a novel use-case of the RIS technology in radio localization, which is enabling the user to estimate its own position via transmitting orthogonal frequency-division multiplexing (OFDM) pilots and processing the signal reflected from the RIS. We demonstrate that user localization in this scenario is possible by deriving Cramér-Rao lower bounds on the positioning error and devising a low-complexity position estimation algorithm. We consider random and directional RIS phase profiles and apply a specific temporal coding to them, such that the reflected signal from the RIS can be separated from the uncontrolled multipath. Finally, we assess the performance of our position estimator for an example system, and show that the proposed algorithm can attain the derived bound at high signal-to-noise ratio values.
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| 8. |
- Keykhosravi, Kamran, 1990, et al.
(författare)
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SISO RIS-Enabled Joint 3D Downlink Localization and Synchronization
- 2021
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Ingår i: IEEE International Conference on Communications. - 1550-3607.
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Konferensbidrag (refereegranskat)abstract
- We consider the problem of joint three-dimensional localization and synchronization for a single-input single-output (SISO) multi-carrier system in the presence of a reconfigurable intelligent surface (RIS), equipped with a uniform planar array. First, we derive the Cramér-Rao bounds (CRBs) on the estimation error of the channel parameters, namely, the angle-of-departure (AOD), composed of azimuth and elevation, from RIS to the user equipment (UE) and times-of-arrival (TOAs) for the path from the base station (BS) to UE and BS-RISUE reflection. In order to avoid high-dimensional search over the parameter space, we devise a low-complexity estimation algorithm that performs two 1D searches over the TOAs and one 2D search over the AODs. Simulation results demonstrate that the considered RIS-aided wireless system can provide submeter-level positioning and synchronization accuracy, materializing the positioning capability of Beyond 5G networks even with single-antenna BS and UE. Furthermore, the proposed estimator is shown to attain the CRB at a wide interval of distances between UE and RIS. Finally, we also investigate the scaling of the position error bound with the number of RIS elements.
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| 9. |
- Kim, Hyowon, et al.
(författare)
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Joint CKF-PHD Filter and Map Fusion for 5G Multi-cell SLAM
- 2020
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Ingår i: IEEE International Conference on Communications. - 1550-3607. ; 2020-June
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Konferensbidrag (refereegranskat)abstract
- 5G is expected to enable simultaneous vehicle localization and environment mapping (SLAM). Furthermore, vehicular networks will be covered with 5G small cells, wherein the map information is collected at each base station (BS) and then fused so as to promote the overall performance of SLAM. In 5G multi-cell SLAM, there are challenges such as the unknown number of targets, uncertainty regarding the association between the targets and the measurements, unknown types of targets, as well as map management among BSs. To address those challenges, we propose a new method for 5G multi-cell SLAM which comprises a joint cubature Kalman filter and multi-model probability hypothesis density, and a map fusion routine. Simulation results demonstrate that the proposed method solves the aforementioned challenges and also improves vehicle state and map estimates.
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| 10. |
- Kolomvakis, Nikolaos, 1985, et al.
(författare)
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Quantized Uplink Massive MIMO Systems with Linear Receivers
- 2020
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Ingår i: IEEE International Conference on Communications. - : Institute of Electrical and Electronics Engineers Inc.. - 9781728150895 ; 2020-June
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Konferensbidrag (refereegranskat)abstract
- This paper considers the uplink of a single-cell multi-user massive multiple-input multiple-output (MIMO) system. Each receiver antenna of the base station is assumed to be equipped with a pair of analog-to-digital converters (ADCs) to quantize the real and imaginary part of the received signal. We propose a novel Bussgang-based weighted zero-forcing (B-WZF) receiver, which distinguishes the clipping and granular distortion. Numerical results demonstrate that for sufficiently high SNR and users that do not experience deep large-scale fading, the B-WZF brings significant performance gain over existing linear receivers in the literature, when the training sequence length is higher than the number of users. © 2020 IEEE.
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