Hasil untuk "Telecommunication"

Ainna Yue Moreno-Locubiche, Josep Vidal, Antonio Pascual-Iserte et al.

This paper proposes the joint design of reconfigurable intelligent surfaces (RIS) and zero-forcing (ZF) precoding for the downlink (DL) multiuser multiple-input single-output (MU-MISO) setup in millimeter-wave (mmWave) bands, where ZF is particularly attractive due to its ability to suppress inter-user interference by exploiting the large antenna arrays and sparse directional channels characteristic of mmWave systems. This ensures efficient spatial multiplexing with manageable complexity, making ZF a practical and in modern 5G/6G deployments. However, a careful design is necessary to overcome potential rank deficiency in the channel matrix. For the MU-MISO case, rank deficiency may arise if users exhibit significantly different channel gains or if, being in far-field, they are aligned with the position of the transmitter. On the other hand, the deployment of a RIS introduces artificial scattering which can shape the radio environment to address those situations. We explore the joint design under perfect channel knowledge, assess the impact of imperfect channel estimation on the bit error rate (BER) and propose a robust design of pilot transmissions that equalizes multiuser interference across users in the presence of channel errors in the precoder design. This evaluation shows the advantages of optimized RIS-aided ZF MU-MISO communication for the DL of wireless systems.

HE Lesheng, FENG Yi, YUE Yuankang et al.

Internet of things (IoT) devices are typically implemented using microcontrollers with limited computational capabilities, which necessitate the use of lightweight symmetric encryption algorithms to ensure data security. Due to their inherent characteristics, these devices can only be deployed in open environments, making them highly vulnerable to side-channel attacks. To address this issue, experiments were conducted on a self-designed side-channel attack validation platform, where a secure key management scheme and an improved S-box design were proposed as countermeasures against side-channel attacks. The validation platform consisted of a two-stage differential amplifier and an anti-interference finite impulse response (FIR) filter, which were capable of capturing subtle power consumption fluctuations. A two-round correlated energy attack targeting lightweight encryption algorithms was also designed. By evaluating the confidence of the correct key correlation coefficient, after 10 000 attacks on 3 000 power consumption traces of the PRESENT algorithm, a success rate of over 96% is achieved, with the mean correlation of the correct key exceeding 0.6. At a 95% confidence level, a narrow confidence interval is obtained. In contrast, when the improved algorithm is used in the same experiment, the attack success rate is only 9.12%.

Snehal D. Patil, Prashant P. Bartakke

With the expeditious advancement in multicarrier automotive in-vehicle monitoring for a bus conforming environment with computer vision, there is an exigency for a setup subsisting on inspection cameras and an onboard embedded computing device. This paper offers a novel method for in-cabin occupant recognition with an integration of hardware subsystem comprising NVIDIA AGX Orin Development Kit, camera sensors, and camera interface serdes card accompanying software components embracing Pytorch, Open Neural Network Exchange (ONNX), TensorRT (TRT), CuPy, CV-CUDA, and NVIDIA Nsight Profiler tool. This work presents an optimized model construction picked up from a pool of state-of-the-art deep learning models and deployment, achieving high accuracy and low latency, furthermore permitting real-time video streaming and inference. The inference performance of an embedded device hiring a Graphic Processing Unit (GPU) and Compute Unified Device Architecture (CUDA) is embellished on TRT with CuPy and CV-CUDA to escalate GPU performance. Each GPU optimization strategy is thoroughly analyzed in the context of design space exploration or on-the-fly tuning. The GPU performance is monitored with the NVIDIA Nsight Profiler tool to knock off the GPU coldspots, GPU starvation, and asynchronous CUDA memory copy operations. The Roofline model analysis in Nsight Compute is used to pinpoint the exact causes of GPU underutilization. The experimental performance showcase to achieve a test accuracy of over 80% with the boost in GPU utilization by a factor of 2.24.

Biljana Angelova, Jusuf Zekiri

Omar M. Salih, Ashwaq Q. Hameed

The most significant challenges wireless broadcasting systems face are channel effects and Inter Symbol Interference (ISI). Many different kinds of channel coding are employed to get around these issues. Digital Video Broadcasting for Satellite Telecommunication Second Generation (DVB-S2) uses a serial concatenation of Bose, Ray-Chaudhuri, and Hocquenghem (BCH) code and Low-Density Parity-Check (LDPC) code as a Forward Error Correction (FEC) for error detection purpose and correction. In this work, a MATLAB code (m-files) is constructed to simulate the standard DVB-S2 Bit-Interleaved Coded Modulation (BICM) system according to the ETSI Technical Report (EN 302 307 1). Then, the traditional design is redesigned with a Parallel Concatenation Convolutional (PCC) Turbo coding in concatenation with LDPC coding to enhance the (FEC). The two approaches have been tested under the official modulation types QPSK, 8PSK, 16APSK, and 32APSK with 2/3, 3/4, 3/5, 4/5, and 5/6 code rates (RC). Over a Rayleigh Fading channel, the two models are compared. The proposed model performed better than the standard model regarding bit error rate (BER) mitigation when operating at varying signal-to-noise ratio (SNR) levels, especially in 8PSK 3/5 MODCODE. The proposed model achieved (2.6272×10-3) BER mitigation value with power gain equal to 4 dB.

Chujun Zhao, Yanhong Zou, Yu Chen et al.

Based on the open-aperture Z-scan measurement, we firstly uncovered the saturable absorption property of the topological insulator (TI): Bi2Se3. A high absolute modulation depth up to 98% and a saturation intensity of 0.49 GWcm(-2) were identified. By incorporating this novel saturable absorber material into an erbium-doped fiber laser, wavelength tunable soliton operation was experimentally demonstrated. Our result indicates that like the atomic layer graphene, the topological insulator Bi2Se3 could also operate as an effective saturable absorber for the passive mode locking of lasers at the telecommunication band.

Youngjong Kang, J. Walish, T. Gorishnyy et al.

C. Clausen, I. Usmani, F. Bussières et al.

Entanglement is the fundamental characteristic of quantum physics—much experimental effort is devoted to harnessing it between various physical systems. In particular, entanglement between light and material systems is interesting owing to their anticipated respective roles as ‘flying’ and stationary qubits in quantum information technologies (such as quantum repeaters and quantum networks). Here we report the demonstration of entanglement between a photon at a telecommunication wavelength (1,338 nm) and a single collective atomic excitation stored in a crystal. One photon from an energy–time entangled pair is mapped onto the crystal and then released into a well-defined spatial mode after a predetermined storage time. The other (telecommunication wavelength) photon is sent directly through a 50-metre fibre link to an analyser. Successful storage of entanglement in the crystal is proved by a violation of the Clauser–Horne–Shimony–Holt inequality by almost three standard deviations (S = 2.64 ± 0.23). These results represent an important step towards quantum communication technologies based on solid-state devices. In particular, our resources pave the way for building multiplexed quantum repeaters for long-distance quantum networks.

Tianyuan Zhang, Sérgio Moro, Ricardo F. Ramos

Numerous valuable clients can be lost to competitors in the telecommunication industry, leading to profit loss. Thus, understanding the reasons for client churn is vital for telecommunication companies. This study aimed to develop a churn prediction model to predict telecom client churn through customer segmentation. Data were collected from three major Chinese telecom companies, and Fisher discriminant equations and logistic regression analysis were used to build a telecom customer churn prediction model. According to the results, it can be concluded that the telecom customer churn model constructed by regression analysis had higher prediction accuracy (93.94%) and better results. This study will help telecom companies efficiently predict the possibility of and take targeted measures to avoid customer churn, thereby increasing their profits.

J. Wind, V. Mahajan

K. Weylandt, A. Sardini, C. F. Higgins et al.

Jia XU, Zhihua JIAN, Honghui JIN et al.

In response to the low accuracy of synthetic speech spoofing detection based on traditional acoustic feature parameters, poor detection performance for unknown types of synthetic speech, and performance degradation in noisy environments, a method for detecting spoofing synthetic speech was proposed using constant Q modulation envelope (CQME) .The motivation of the method was from the fact that the temporal envelope of speech contained abundant information and there was a big difference in detail between the envelope of synthetic speech and genuine speech.The modulation envelope spectrum of speech was obtained by employing constant Q transform (CQT), and the root mean square of each frequency component was calculated to derive the CQME feature vector.And then the CQME feature vector was used to train the random forest classifier for discriminating genuine speech from spoofing synthetic speech.Experimental results demonstrate that the random forest trained with CQME features achieves high detection performance on the ASVspoof 2019 dataset and exhibites good detection efficacy for unknown types of synthetic speech.Furthermore, the proposed method shows high detection performance even under various noise conditions, having excellent noise robustness.

B. Huang, Mohand Tahar Kechadi, Brian Buckley

V. Rosato, L. Issacharoff, F. Tiriticco et al.

Liping Gao, Onne Janssen, K. Shi

J. V. Bemmel, M. Musen

N. Shinohara

Emine Kılıçparlar Cengiz, Abdurrahman Neyal, Yasemin Ekmekyapar Fırat et al.

Objective:Coronavirus disease-2019 (COVID-19) pandemic mentioned some disease-specific problems related to obstructive sleep apnea syndrome (OSAS). This study determined problems faced by patients using positive airway pressure (PAP) devices due to OSAS during the COVID-19 pandemic.Materials and Methods:Patients with OSAS using PAP were retrospectively identified. The cases that were contacted by phone were invited to complete the survey. Patients who agreed to participate in the study were asked whether the pandemic process affected their daily lives, OSAS treatment and PAP device use, and their responses were recorded.Results:Fifty patients (37 men/13 women) included in this study. Eleven cases had a history of COVID-19 infection; however, the disease symptoms were not severe in any case. Half of the patients reported that daily living was moderately or severely affected during the pandemic. Eight patients experienced problems with their PAP devices, five patients started to use the PAP devices irregularly during the pandemic, and 10 cases completely stopped using them.Conclusion:A significant portion of the patients experienced serious problems with PAP devices and the daily living activities were affected in half of the them during the pandemic. However, the follow-up and treatment services for many chronic diseases, as for OSAS, have been interrupted in this period that obligate the patients to handle their condition on their own. To provide continuous and adequate health care for OSAS patients under similar conditions in the future, it may be beneficial to establish widespread remote telecommunication systems in advance.

M. Mahmoud, R. Hinson, P. Anim

Xiaoyong Fu, Qinghua Zhu, Joseph Sarkis