Abstract:To meet the application requirements of multi-antenna beamforming in 5G mobile communications, this paper designs and implements a multi-channel Software Defined Radio (SDR) communication system, and based on this system, achieves broadband multi-channel multi-frequency point synchronization calibration. To address the issue of multi-channel synchronization drift due to environmental factors such as temperature, this paper innovatively proposes a real-time synchronization scheme based on out-of-band calibration signals. This scheme inserts calibration signals into the redundant bandwidth of OFDM communications to track the drift of multi-channel response errors over time and compensates for the in-band effective signals. At the 1 GHz frequency point, the system effectively compensates for the phase response error drift of 2.8 ℃ and amplitude response error drift of 0.2 dB caused by temperature variations through real-time calibration. After initialization calibration and real-time calibration, the phase error is controlled within 0.4 ℃, and the amplitude response error is controlled within 0.05 dB in the temperature range of 40 to 80 ℃. This scheme not only achieves higher precision but is also completely transparent to the end user, allowing calibration without interrupting communication operations, making it highly significant for the design of 5G multi-channel synchronization.

Abstract:This article addresses the issue of low-frequency mechanical energy in the human body and the relatively low energy harvesting efficiency of traditional contact-separation nanogenerator. A novel assisted-structure nanogenerator designed for self-powered communication systems is proposed to tackle this problem. The assisted-structure can effectively transmit and enhance forces, which can reduce the excitation required by the triboelectric nanogenerator for energy collection by 8.6 times with similar output performance. With the aim of self-powered communication, after encoding information, the human body′s mechanical energy acting on the assisted-structure nanogenerator is utilized to modulate and transmit the signals. In the voltage signal, a half-wave rectification circuit is designed to reduce the influence of positive and negative half-axis waveform asymmetry of the voltage waveform of the TENG. The analog voltage signal corresponding to the power assisted structure nanogenerator is collected and after corresponding demodulation and decoding, the original information can be recovered. The experiment successfully transmitted the string NJUPT.

Abstract:The integration of the integrated communications/navigation/identification (ICNI) system for unmanned aerial vehicles necessitates that the master control module of the ICNI performs functions such as system control and data forwarding via multiple bus communications. This requirement imposes higher demands on the processing performance and interface resources of the core processor. Consequently, there is a need for a more lightweight design for the health control system within the module. This paper presents a fully domestic CAN bus-based health management system designed using a CPU+MCU distributed architecture within the main control module. The FT-2000/4 serves as the core processor, while the MCU acts as the coprocessor to implement the CAN bus interface unit. The two components facilitate application layer data exchange over the CAN bus through SPI full-duplex communication, enabling the CPU to query the status and issue commands to each module/unit in the system, thereby achieving effective health management. The system is capable of real-time monitoring of the health status of each module. Notably, the circuit design utilizes only the SPI and GPIO interfaces of the core processor, without occupying additional interface resources or programmable logic (FPGA) resources. This approach simplifies the hardware design and alleviates the challenges associated with circuit layout and structural design. Furthermore, the cost of the health management circuitry is at least 60% lower than that of other typical designs in the industry, addressing the need for cost-effective solutions.

Abstract:In order to solve the problem of spectrum scarcity and frequent user switching in wireless networks, this paper proposes a VLC-WiFi heterogeneous access and hysteresis soft switching algorithm based on quadrant segmentation. According to the three-dimensional coordinate system, the indoor area is divided into four parts to establish a user rate model, obtain the user rate, and establish an occlusion model to simulate the scenario of VLC link being occluded. Users perform access operations based on parameters such as location, quadrant, occlusion, and speed. Switching differentiates the threshold between inward switching and outward switching based on hysteresis, creating a flexible space for switching and suppressing the ping pong effect. In the 5 m×5 m×5 m indoor space, multiple experiments have shown that the indoor VLC-WiFi heterogeneous networking scheme proposed in this article reduces the number of horizontal switches by 43.8%, the number of occlusion and vertical switches by 45.3%, the number of ping-pong times by 52.27%, and the throughput by about 5.84% compared to traditional algorithms. This algorithm can significantly reduce switching and ping-pong times. Therefore, this article provides a theoretical basis for the study of indoor heterogeneous network communication.

Abstract:To meet the needs of UUV cluster collaborative communication in complex marine environments, a magnetic induction communication system based on BPSK is proposed. A channel transmission model is established to analyze the effects of different transceiver models, seawater, carrier synchronization, and carrier frequency on channel transmission, combined with MATLAB simulations and experiments for validation. Simulation results show that BPSK modulation performs well under complex channel conditions; the one-to-three receive model is insensitive to attitude changes; phase offset is a major factor in the effects of eddies, and carrier synchronization significantly reduces its impact. Ultimately, the results indicate that the bit error rate decreases to the order of 10-3, effectively meeting the collaborative communication needs of UUV clusters,validating the system′s high stability and reliability in complex marine conditions. Finally, hardware experiments further validate the feasibility of the system.

Abstract:Semantic communication is a type of communication designed to convey semantic information, which is characterized by the fact that it can effectively reduce redundancy and the amount of transmitted data. Currently the research on semantic communication is only in its infancy, and more theoretical research can help to promote the real implementation of semantic communication systems. The core technology for realizing semantic communication, end-to-end joint source channel coding, has made great progress in the past few years, and semantic images have also been developed. In order to solve the problems of computational inefficiency and insufficient semantic feature extraction, a new neural network JSCC is designed in this paper.Specifically, inspired by the excellent performance of Swin Transformer in visual tasks, the Swin-Transformer module is combined with residual networks for the first time, and a Swin Transformer-based image semantic communication system. In order to solve the problems such as the poor efficiency of traditional CNN for image feature extraction, the attention residual network module is introduced to extract the image semantic features initially, and then the image semantic features are further extracted by Swin Transformer. Through the verification of the experimental results, compared with the existing schemes, the proposed scheme in this paper achieves higher than 2 dB performance improvement in PSNR and more than 5% performance improvement in MS-SSIM performance

Abstract:Liquid pharmaceuticals filled with vials are widely used and stored in hospitals and pharmacies. In order to achieve realtime monitoring of such agents, an on-line monitor was designed with photoelectric sensor, STM32 main control chip and UDP communication protocol. The light intensity parameters of the photoelectric sensor used in the monitor are calculated according to the inverse square law of direct illumination distance of point light source, and verified by Comsol simulation platform. The monitor uses photoelectric sensors to monitor the number of drugs in real time and synchronize drug information. The designed PCside drug monitoring software uses UDP protocol to connect multiple drug monitors to achieve onetomany online monitoring functions. The monitor can use a variety of power supply methods to monitor the ambient temperature in real time, and meet the needs of various types of vials filling liquid pharmaceuticals in multiple scenarios and multiple environments. The test results show that the power consumption of the monitor is 3.08 W, 3.23 W and 3.35 W at no-load, half-load and full-load, respectively, and the monitoring accuracy of the remaining number of vials is 100%. Combined with the low cost features, the monitor is worth promoting in hospital pharmacies, retail pharmacies and other places.

Abstract:Aiming at the problem of co-channel interference when users reuse spectrum resources in D2D communication, an improved Hunter prey optimization algorithm is proposed to control the power of D2D users. It adjusts the D2D transmission power according to the rules that the hunter moves to the prey and the prey moves to the safest position under the constraints of satisfying the communication quality of the system users. The Sobol sequence initializes the population, and introduces the water wave dynamic adaptive factor into the predator position update formula, so as to determine the optimal transmit power of D2D users. The simulation results show that the algorithm can not only improve the total throughput of the system and reduce the interference to cellular users, but also improve the convergence speed and optimization accuracy.

Abstract:This paper studies the radar servo multi-channel communication platform of domestic devices. Aiming at the problems of autonomous control of radar servo system hardware and complex multichannel communication, a domestic radar servo multichannel communication system based on MCU+FPGA architecture is proposed to improve the reliability, redundancy and universality of servo control. A 6way RS422 fusion structure is designed to complete the communication with each subsystem component, In addition, the device schematic design and PCB layout and wiring are completed on Altium Designer, and the 6layer stack design and physical static test of PCB are realized. The test results show that the communication system of this design meets the design requirements and can realize domestic substitution.

Abstract:Non-line-of-sight link visible light communication has the advantages of wide signal coverage and not easy to block the link due to occlusion. However, there are some problems, such as weak link signal and small field of view of the receiving system using a single detector. Aiming at the above-mentioned problems, a receiving mode of multi-detector fusion is proposed. The influence of receiving azimuth angle on the received signal is studied experimentally, the signal-to-noise ratio distribution of the received signal based on the single-detector receiving system and the four detectors receiving system is measured respectively, and the communication performance of the non-line-of-sight link communication system based on four detectors is tested. Experimental results show that the multi-detector fusion receiving method can effectively improve the performance of the non-line-of-sight link communication system, the maximum signal-to-noise ratio of the system with non-line-of-sight link communication can be increased by 10.71 dB by using four detectors, and the maximum communication rate of the system can reach 1 Mbps and the bit error rate is less than 10-6 when the line-of-sight link is completely blocked.