A5031956158- PAPR reduction in OFDM
- Advanced Wireless Communication Techniques
- Indoor and Outdoor Localization Technologies
- Millimeter-Wave Propagation and Modeling
- Speech and Audio Processing
- Wireless Communication Networks Research
- Advanced Wireless Communication Technologies
- Optical Wireless Communication Technologies
- Advanced Power Amplifier Design
- Radio Frequency Integrated Circuit Design
- Bioactive Compounds in Plants
- Advanced MIMO Systems Optimization
- Optical Network Technologies
- Wireless Signal Modulation Classification
- Radar Systems and Signal Processing
- Advanced Adaptive Filtering Techniques
- IoT Networks and Protocols
- Microwave Engineering and Waveguides
- Power Line Communications and Noise
- Wireless Body Area Networks
- Orbital Angular Momentum in Optics
- Blind Source Separation Techniques
- Bluetooth and Wireless Communication Technologies
- Antenna Design and Optimization
- Antenna Design and Analysis
Vodafone (Germany)
2017-2025
TU Dresden
2017-2024
Vodafone (Portugal)
2022
Deutsche Telekom (Germany)
2022
Technische Universität Ilmenau
2015
IEEE 802.11p standard is specially developed to define vehicular communications requirements and support cooperative intelligent transport systems. In such environment, reliable channel estimation considered as a major critical challenge for ensuring the system performance due extremely time-varying characteristic of channels. The preamble based, which becomes inaccurate in high mobility scenarios. track variations over course packet length while adhering specifications. motivation behind...
Chirp spread spectrum (CSS) is the modulation technique currently employed by Long-Range (LoRa), which one of most prominent Internet things wireless communications standards. The LoRa physical layer (PHY) employs CSS on top a variant frequency shift keying, and non-coherent detection at receiver. While it offers good trade-off among coverage, data rate device simplicity, its maximum achievable still limiting factor for some applications. Moreover, current standard does not fully exploit...
Orthogonal time frequency space modulation (OTFS) has been recently proposed to achieve and diversity, especially in linear time-variant (LTV) channels with large Doppler frequencies. The idea is based on the precoding of data symbols using symplectic finite Fourier transform (SFFT) then transmitting them by mean orthogonal division multiplexing (OFDM) waveform. Consequently, demodulation channel equalization can be coupled one processing step. As a distinguished feature, demodulated have...
In this paper, we investigate three different concepts for robust link-level performance under doubly-dispersive wireless channels, namely, i) channel estimation, ii) cyclic prefix (CP)-free transmission, and iii) waveform design. We employ a unique word-based where decouple the related errors into estimation error (CEE) Doppler (DE). Then, show that trade-off between CEE DE emerges in frame design, system can be optimized to achieve minimum composite error. Another strategy improve is...
Least square (LS) channel estimation employed in various communications systems suffers from performance degradation especially low signal-to-noise ratio (SNR) regions. This is due to the noise enhancement LS process. Minimum mean error (MMSE) takes into consideration effect and achieves better than with higher complexity. paper proposes correct using deep learning (DL). Simulation results show that proposed DL-based schemes perform both MMSE scheme, less complexity accurate MMSE.
IEEE 802.11p standard defines wireless technology protocols that enable vehicular transportation and manage traffic efficiency. A major challenge in the development of this is ensuring communication reliability highly dynamic environments, where channels are doubly selective, thus making channel estimation tracking a relevant problem to investigate. In paper, novel deep learning (DL)-based weighted interpolation estimator proposed accurately estimate especially high mobility scenarios. The...
Communication using orbital angular momentum (OAM) modes has recently received a considerable interest in free space optical (FSO) communications. Propagating OAM through may be subject to atmospheric turbulence (AT) distortions that cause signal attenuation and crosstalk which degrades the system capacity increases error probability. In this paper, we propose enhance FSO communications terms of bit rate spectral efficiency, for different levels AT regimes. The performance gain is achieved...
The services foreseen for 5G networks will demand a vast number of challenging requirements to be fulfilled by the physical layer. These can grouped into application scenarios, each one with key requirement addressed network. A flexible waveform associated appropriate data frame is an essential feature in order guarantee support contrasting from different scenarios such as Enhanced Mobile Broadband, Internet Things, Tactile and Access Remote Areas. In this paper, we propose based on...
In this paper, we study the problem of euclidean distance matrix (EDM) recovery aiming to tackle received signal strength indicator sparsity and fluctuations in indoor environments for localization purposes. This is addressed under constraints required by internet things communications ensuring low energy consumption reduced online complexity compared classical completion schemes. We propose EDM methods based on neural networks that allow an efficient denoising. A trilateration process then...
In this letter, we present a generic modulation framework for robust wireless communications over doubly dispersive channels. This robustness is achieved by spreading the symbols time and frequency such that they experience same channel gain. Interestingly, show our generalization of recently proposed orthogonal space (OTFS). By exploiting an additional degree freedom enabled framework, propose in letter low-complex waveform based on sparse Walsh-Hadamard transform (WHT). We WHT exhibits...
For a linear waveform, finite condition number of the corresponding modulation matrix is necessary for waveform to convey message without ambiguity. Based on Zak transform, this letter presents an analytical approach compute multi-carrier generalized frequency division multiplexing (GFDM). We further propose filter design that yields non-singular matrices even subcarriers and subsymbols, which not achievable any previous work. Such new has significant impact implementation complexity, as...
This paper describes a coherent chirp spread spectrum (CSS) technique based on the Long-Range (LoRa) physical layer (PHY) framework. LoRa PHY employs CSS top of variant frequency shift keying (FSK), and non-coherent detection is employed at receiver for obtaining transmitted data symbols. In this paper, we propose scheme that encodes information bits both in-phase quadrature components signal, rather detector receiver. Hence, channel equalization required compensating induced phase rotation...
IEEE 802.11p standard enables the wireless technology that defines vehicular communications. However, frame structure employing low pilot density is not enough to track channel variations in high mobility scenarios, leading significant performance degradation. Therefore, ensuring communication reliability environments considered as a major challenge. In this work, challenge tackled by deep learning into conventional estimation through utilizing neural networks (DNN) an additional non-linear...
Joint communications and radar sensing (JC&S) is expected to be one of the key features in next-generation wireless communication systems, main enablers for this availability very wide bands millimeter-wave (mmWave) frequencies. Most literature has investigated different aspects JC&S by means theoretical or simulation studies. However, before concept fully understood applied practice, prototyping large-scale experiments are needed. In paper, we present two mmWave demonstration testbeds...
The channel impulse response (CIR)-based localization requires estimating the path delays at a certain position. Several state-of-the-art (SoA) approaches have been proposed to estimate based on eigendecomposition. However, they are limited by assumption of uncorrelated paths, which is not accurate in context localization. attempt mitigate rank deficits problem means frequency smoothing (FS) considerable amount measurements different center frequencies. Another solution with single snapshot...
This paper describes a blind transmitter localization technique based on the deep neural network (DNN) framework. Blind assumes no previous knowledge transmit signal. It is shown that DNN location approaches maximum likelihood solution with reduced computational complexity. Moreover, likelihood, least squares and radio environment map estimators are presented in order to compare design performance of proposed algorithm. The system model built wireless sensor collects received signal strength...
This work presents an investigation on the scalability of a deep leaning (DL)-based blind transmitter positioning system for addressing multi localization (MLT) problem. The proposed approach is able to estimate relative coordinates non-cooperative active transmitters based solely received signal strength measurements collected by wireless sensor network. A performance comparison with two other solutions MLT problem are presented demonstrating benefits respect DL approach. Our aims at...
The projected sub-THz (100 - 300 GHz) part of the upcoming 6G standard will require a careful design waveform and choice slot structure. Not only that physical layer for be driven by ambitious system performance requirements, but also hardware limitations, specific to frequencies, pose fundamental constraint waveform. In this contribution, general guidelines are given, together with non-exhaustive list exemplary waveforms can used meet requirements.
In this paper, we investigate the physical layer (PHY) performance of generalized frequency division multiplexing (GFDM) for high throughput wireless communication. For comparison purposes, orthogonal (OFDM)-based IEEE 802.11ac PHY is used as a benchmark. Harnessing flexibility GFDM, propose novel configuration, being compliant to data transmission. With that can achieve not only lower out-of-band (OOB) emission but also higher spectral efficiency. By further deriving corresponding receiver,...
Current wireless networks prioritize spectral efficiency, however, energy efficiency has become crucial due to environmental, monetary, and device design considerations. The recently proposed Gearbox physical layer (PHY) approach dynamically switches between modulation schemes including corresponding transceiver front ends optimize considering availability required data rates. contribution of this work is the prediction energy-saving potential a Gearbox-PHY with flexible for linear amplitude...
As the fifth generation (5G) mobile communication systems are commercially deployed, they bring new services, enhance user experiences, and offer various opportunities to different industries. Despite its advancements, 5G encounters several challenges. To tackle these issues, global industrial, academic, standards organizations actively researching on sixth (6G) wireless systems. 6G networks envisioned as a transformative shift in interactions between physical, digital, human realms, paving...