Residue Number Systems (RNS) offer a promising approach to enhancing the computational efficiency of Fully Homomorphic Encryption (FHE). This paper proposes an efficient base conversion method for RNS, leveraging parallel Processing Unit (PU) cores, where each PU core operates under different moduli, along with a Karatsuba-based Barrett modular multiplier to accelerate modular arithmetic in homomorphic encryption schemes. Our approach addresses the computational bottleneck of base conversions in FHE by utilizing optimized parallelism and efficient multiplication methods. Experimental results show that, with nearly the same latency for the computing unit, the proposed design can achieve higher throughput for implementing base conversion (BConv). The performance is further evaluated with different parallel core configurations (2, 3, and 6 cores), and these scenarios are compared against a single-core implementation. The design with 6 parallel cores achieves more than 5Gbps, demonstrating the significant benefit of increased parallelism for BConv in FHE operations.

Fully homomorphic encryption is an encryption that allows direct mathematical operation on its ciphertext. One of the challenges of implementing FHE is the costly operation of polynomial multiplication over an integer ring. One the of candidates to solve this problem is using Number Theoretic Transform (NTT) which is an FFT evaluated on integer ring. In this paper, we propose a unified reconfigurable radix for the NTT-INTT operation to balance between the flexibility of radix-2 to process 2Npoints of polynomial and low computational cycle of higher radix. Experimental results indicate a significant improvement up to 9.06× in throughput per slice when compared to recent alternative designs handling large polynomial inputs (≥ 12), although it remains inferior to architectures optimized for smaller inputs. Nonetheless, this reconfigurable design provides a viable pathway to enhance overall throughput by capitalizing on parallel processing, albeit at the cost of an increased number of slices.

Orthogonal frequency-division multiplexing (OFDM) is widely used in modern wireless, telecommunications, and broadcasting standards due to its multipath tolerance and high spectral efficiency. It enables high-data-rate transmission while mitigating inter-symbol interference by extending symbol duration. Many OFDM system designs have been developed, but most of them have put a halt on MATLAB simulation or register-transfer level (RTL) implementation only, lacking real-time testing and TCP/IP integration -- a feature that is needed in many wireless communication devices nowadays. This paper presents a full design integration and implementation of an OFDM transceiver system on the ADRV9361-Z7035 Software-Defined Radio (SDR) FPGA development board, which integrates the AD9361 RF Agile Transceiver with the Xilinx Z7035 Zynq-7000 SoC. The design process includes creating MATLAB models for each OFDM block, developing system objects for data transmission, and verifying the system using an SDR MATLAB model. The implementation involves constructing an RTL model and developing Linux kernel drivers for local processing, independent of MATLAB and Simulink. Transmitter power performance measurements across various modulation and coding schemes indicate optimal performance within the 700 MHz to 900 MHz range, with a maximum power of 13.6 dBm using BPSK FEC 1/2. Receiver sensitivity measurements show that most modulation and coding schemes (MCS) have met their standard sensitivity levels. Throughput performances for each MCS were compared to theoretical values and benchmarked against the Silvus Streamcaster 4200, highlighting strong performance across the MCS, with minor areas for improvement in 16-QAM configurations. The integrated OFDM system has been able to be used for multimedia applications, such as local video streaming and internet browsing.

Optical wireless communication (OWC) has been considered a promising solution for overcoming the spectrum limitations of RF in wireless communication. However, studies on OWC systems, particularly on actual real-time prototyping, are limited and only focus on simulation and experiments using waveform generators and oscilloscopes. Meanwhile, the data rate requirements for optical communication systems are rapidly increasing, approaching the Gbps range. Therefore, the development of real-time prototypes with high data speeds is essential and requires super sample rates (SSR), necessitating signal processing blocks capable of processing multiple samples in parallel within a single clock cycle while operating at very high clock frequencies. To address these requirements, this work proposes a parallel implementation of an orthogonal frequency division multiplexing (OFDM) baseband processor on an FPGA for OWC systems. The proposed system operates with a bandwidth of 320 MHz, achieving a maximum raw data rate of 720 Mbps at 16-QAM 3/4 modulation. This performance is comparable to that of the IEEE 802.11be WiFi 7 standard. The proposed system is applicable not only to underwater OWC but also for indoor OWC (e.g. Li-Fi), broadening its potential use cases in next-generation wireless communication networks.

Light Fidelity (Li-Fi) is the complementary technology to the RF based communication in 6G. It uses optical spectrum which is completely free and unregulated. Sampling frequency offset (SFO) is an issue related to the mismatch between TX and RX clock oscillators. However, this issue is often assumed to be ideal in many Li-Fi research. In this work, we aim to address this issue by proposing an FPGA implementation of SFO compensator module for OFDM system. We optimize an SFO compensation method so that it can be implemented in FPGA efficiently in terms of resource usage. We evaluate the module by integrating it with the OFDM processor, Linux TCP/IP stack, and tested with TCP data. Real-time experiment results demonstrate that with our SFO compensator, the EVM of our Li-Fi system can be decreased up to 6.7% and 1.4% for QPSK and 16-QAM, respectively. Frame lost is decreased by 22.42% and TCP data rate is increased by 8.25x.

The computationally intensive of polynomial ring multiplication in homomorphic encryption (HE) schemes demand an optimized hardware accelerator design, specifically targeted for edge devices. The state-of-the-art algorithm for calculating polynomial ring multiplication is the Number Theoretic Transform (NTT) which is capable of reducing the number of operations needed from the school book multiplication algorithm. In this work, we propose a novel NTT hardware accelerator design that is suitable for use in implementing a partially homomorphic encryption scheme with a 192-bit level of security. The main novelty presented in this paper is the realization of an area-efficient higher radix NTT and inverse NTT (INTT) accelerator which is achieved via mathematical optimization and a point-based approach to calculating NTT. Compared to previous works with similar throughput per slice metric, the design is able to deliver 5.16× higher throughput for a 2.46× increase in slice count.

Reinforcement Learning is a machine learning method that has been adopted in smart traffic lights to reduce traffic congestion effectively. The algorithm is employed as an agent, like a traffic police officer, that can manage traffic jams with the intelligent capability. In this paper, we revisit the basic Q- Learning method applied to adaptive traffic lights by proposing systematic state-action definition, formulating reward policy, and evaluating the performance. The proposed method basically aims to adjust the duration of green lights at each intersection according to the level of congestion at that intersection dynamically, hence, can adapt with traffic condition. Simulation results confirm that the propose method works effectively in managing traffic congestion by maintaining vehicle queue length almost constant at around 40 vehicles queue, offering an improvement from the conventional method that give growth in queue more than 60 vehicles. In the future, we plan to implement the proposed work in an embedded hardware systems to address the real-time performance requirement.

This work presents a comparative study of frequency-based modulation techniques for visible light communication (VLC). The study focuses on frequency shift keying (FSK) and frequency shift chirp modulation (FSCM) schemes, considering their performance in bandwidth-limited channels. FSCM exhibits superior performance over FSK in scenarios characterised by bandwidth limitations and frequency-selective channels, making it an energy-efficient choice. In two experiments conducted in free-space and underwater channels, FSCM yielded higher data rates with lower energy requirements than FSK. These results corroborate the simulation findings of performance in band-limited channels.

This article proposes a scalable accelerator for deep learning (DL) implementation on edge computing, which is often limited by power, storage, and computation speed. The accelerator is based on systolic array cores with 126 processing elements (PEs) and optimized for YOLOv3-Tiny with$448\times448$input images. Two multicast (MC) network architectures, feature map multicasting and weight multicasting, are introduced to control data stream distribution within the multicores. Results show that the proposed weight multicast (W-MC) systems outperformed the feature map multicast (FMAP-MC) systems in multicore scenarios, with up to$2.23\times $frame rates per second (FPS). The 4-core W-MC system achieved the best efficiency with an overall frame rate of 13.73 FPS/W and an overall throughput of 35.83 GOPS/W. The 8-core W-MC system delivered the best performance, with a frame rate of 38.50 FPS after normalization to the standard YOLOv3-Tiny network. The proposed accelerator offers better computational efficiency and greater accelerator utilization in real-world inference scenarios, compared to previous state-of-the-art works.

In this brief, a relaxation oscillator with comparator delay compensation is presented. Two digital compensation loops are introduced to compensate for the comparator delay. This relaxation oscillator is fabricated in the 0.18-μm CMOS process. The measured average oscillation frequency is 943.1 kHz. The whole oscillator consumes 5.2 μW under a 0.9-V supply. The measured average temperature coefficients (TCs) of the oscillation frequency with and without compensation are 93.88 and 618.17 ppm/°C, respectively. It achieves a TC improvement of 6.6×. The measured frequency variation is within ±0.7% from -10 °C to 100 °C by using the DCLs. The measured line sensitivity is 4.37%/V. The measured figure of merit (FOM2) is 173.3 dB.

In this study, data transmission over step-index plastic optical fiber (SI-POF) is demonstrated using orthogonal frequency division multiplexing (OFDM) scheme with sub-carrier pairwise coding (PWC). To investigate the performance of OFDM with PWC, a simulation study is implemented with QPSK and 16-QAM format using the Gaussian theoretical frequency response for a 60 m SI-POF channel. For a data rate of 200 Mbps with QPSK-OFDM, the study shows that compared to equalization, PWC offers about 1.5 dB improvement at a bit-error-rate (BER) of 10-3. An experiment is then set-up with a 60 m SI-POF that uses an eye-safe resonant cavity light emitting diode (RC-LED) as the optical source. The experiment shows that at a bit rate of 200 Mbps with QPSK-OFDM, PWC offers a 1.82 dB improvement in SNR at a BER of 10-3. For the same data rate with 16-QAM-OFDM, PWC offers about 1.1 dB Q2-factor improvement for a modulation index of 0.8. The study therefore shows that PWC improves the BER performance of an SI-POF link that uses OFDM.

In this work, an RGB light-emitting diode (LED) lamp was designed for a smart home system. The ultimate aim of this research is to produce an energy-efficient as well as an environmentally-friendly lamp that is able to be utilized for primarily home activities. The RGB lamp device is made-up of an STM32L100 microcontroller, which controls an SMD-5050 RGB LED lamp using pulse-width modulation (PWM). The RGB lamp device itself is controlled by the user using Android-based application, which communicates using Bluetooth with a central host that passes the command to the lamp device through Zigbee protocol. The end-result of this work is an RGB lamp that uses 42.8 mA current consumption in an idle condition and 603.1 mA in active condition for 5 VDC supply voltage.

We reported the practical implementation of a real-time image-based human detection in FPGA. The Histogram of Oriented Gradients (HOG) features and the AdaBoost classifiers are used as an approach. The systolic array architecture based Support Vectoring Machine (SVM) processing is also implemented in our system. According to the results, it can be shown that the humans are successfully detected from a 1280 x 1024 of image resolution with 129 fps of frame rate, it is not only from the front and back views (horizontal axis) but also robust in human detection from different angles (vertical axis). We also compared our architecture with other works.