Doppler Shift Tolerance of Typical Pseudorandom Binary Sequences in PMCW Radar

Oliveira, Lucas Giroto de; Antes, Theresa; Nuß, Benjamin; Bekker, Elizabeth; Bhutani, Akanksha; Diewald, Axel; Alabd, Mohamad Basim; Li, Yueheng; Pauli, Mario; Zwick, Thomas

doi:10.3390/s22093212

Cited by 14 publications

(5 citation statements)

References 38 publications

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“…In addition, this path is the shortest propagation from Tx to Rx via a single RIS and, therefore, will not overlap with any valid UE detection. Besides the aforementioned targets, there are also other contributions along the y-axis at null velocity, which result from the signal reflections in RF circuits due to imperfect matching and the sinc-behaviour leakage when the target position is not exactly located at the discrete distance values [47]. Nevertheless, these values are at least 25dB weaker than the peak, which will not lead to any UE position estimation error.…”

Section: B Ris-jcas Radar Imagementioning

confidence: 99%

User Detection in RIS-Based mmWave JCAS: Concept and Demonstration

Li,

de Oliveira,

Diewald

et al. 2024

IEEE Trans. Wireless Commun.

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In this article, joint communication and sensing (JCAS) is combined with reconfigurable intelligent surfaces (RISs), which validates a novel RIS-based JCAS (RIS-JCAS) system. The proposed system performs monostatic sensing to detect a potential user, after which communication with the user is established. The corresponding RIS-cascaded channel is formulated, based on which an algorithm is created, to handle radar target detection and communication channel estimation while multiple RISs operate simultaneously. A joint beam training process by utilizing the identical beamforming pattern on multiple RISs is created, which increases the time efficiency significantly. The detection accuracy is subsequently further improved through a novel fine-tuning method. To practically validate the aforementioned algorithm, a RIS-JCAS system is demonstrated using a mmWave testbed with a bandwidth of 1 GHz centralized at 26.2 GHz. Besides combining the widely adopted orthogonal frequency-division multiplexing (OFDM) scheme with high-directional RIS beams, the system also allows the use of variant RIS flat-top beam shaping combined with orthogonal chirp-division multiplexing radar (OCDM) waveforms. This idea keeps the sensitivity of the RIS-JCAS system while broader beams with wider coverage but lower gain are utilized. Overall, accurate 4-dimensional sensing results are derived, which strongly assists the communication channel estimation and realizes the core benefits of the proposed RIS-JCAS system.

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Section: B Ris-jcas Radar Imagementioning

confidence: 99%

User Detection in RIS-Based mmWave JCAS: Concept and Demonstration

Li,

de Oliveira,

Diewald

et al. 2024

IEEE Trans. Wireless Commun.

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“…To assess the proposed sequence, we conducted a comparative study against sequences commonly used in MIMO literatures [38,[42][43][44]. This study involved using Doppler cuts of the ambiguity and cross-ambiguity function responses and graphically presenting the variation of Peak Sidelobe Level (PSLL) and Integrated Sidelobe Level (ISLL) for different code lengths as shown in Figure 3.…”

Section: C) Assessment Of Convergencementioning

confidence: 99%

Sequence optimisation for compressed sensing CDMA MIMO radar via mutual coherence minimisation

Nagesh,

González‐Huici,

Bathelt

et al. 2024

IET Radar Sonar & Navi

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The authors focus on the waveform design for Code Division Multiple Access Multiple Input Multiple Output (CDMA‐MIMO) radar systems, with a specific emphasis on Compressed Sensing (CS) based target estimation. The selection of an appropriate waveform is a critical determinant in the effectiveness of estimation algorithms. Recent studies show the possibilities of optimising waveform parameters to improve the efficiency of CS based estimation. The authors introduce an optimisation framework designed to modify the phase components of code sequences used in CS‐CDMA MIMO radar systems. The objective of this optimisation is to minimise the l∞ norm of off‐diagonal elements within the Gramian matrix of the underlying sensing matrix, focusing on phase modulation of the waveform. Solving this optimisation problem requires dealing with a non‐convex, combinatorial and non‐linear scenario. Simulated Annealing is employed as the solution technique. To assess the effectiveness of the proposed optimisation approach, the resulting optimised sequence is rigorously compared against well‐established Hadamard and Gold sequences across various performance metrics. These metrics encompass correlation properties, ambiguity function behaviour, recovery percentage and recovery error. The study demonstrates that the generated poly‐phase sequences outperform existing sequences, leading to significantly improved target reconstruction results in the context of CDMA‐MIMO radar systems with CS‐based estimation.

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“…, which affects the receiving performance of the proposed information transmission method in the high-speed moving environment [3] . Therefore, the doppler frequency shift caused by the high-speed movement of UAV during the execution of tasks is a great challenge to the information transmission process of UAV data link [4] .…”

Section: Different Modulation Modesmentioning

confidence: 99%