data buffer
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Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Jiaojiao Hu ◽  
Zhihui Wu ◽  
Lei Jin

The protection of cultural relics has always been an important issue in the field of museums and archaeology. With the development of Internet of Things technology, the security system of the museum is more intelligent and integrated. In order for the museum display system to keep up with the intelligent age, this article mainly studies the research and realization of the museum showcase system based on the Internet of Things technology in a smart environment. Before the start of the experiment, we developed the overall design of the system, including three functional modules: temperature module, illumination module, and monitoring module. The experiment is done mainly for system testing. The performance test of the sensor module needs to sample the temperature and humidity sensor to verify the accuracy of the temperature and humidity signal collected in the instrument circuit. The light information collection test uses the ADC sampling inside the CC2530 to obtain the required data and judges whether these temperature, humidity, and light intensity values exceed the preset values. The serial port needs to be initialized to carry out data communication and transmission normally. After the receiving end finishes receiving, the sending end will clear the data buffer to prepare for the next data transmission. The experimental data show that the error between the predicted value and measured value of the temperature system is about 3°C, which is within the allowable error range of the experiment. The results show that the system has perfect functions, is safe and reliable, meets the expected requirements, and has good practicability.


Author(s):  
Hailuan Liu ◽  
Lingyan Fan ◽  
Jianjun Luo ◽  
Guorui Feng

2020 ◽  
Author(s):  
Nguyen Nhu Thang ◽  
Tran Manh Hoang ◽  
Ba Cao Nguyen ◽  
Phuong T. Tran

Abstract Recently, non-orthogonal multiple access (NOMA) has been considered as a promising candidate for next-generation mobile communications because it can significantly improve the spectral efficiency of wireless networks. In this paper, we investigate a novel solution to enhance the reliability and the supply stability of a downlink NOMA relaying networks, in which we integrate two techniques: (i) simultaneous wireless information and power transfer, i.e. the relay node can harvest the energy from source signals and use this energy to help forward information from source node to two user nodes; and (ii) data buffer aid at relay node, i.e. the data packets received from the source can be stored in a buffer and then be re-transmitted to the destination nodes only when the channel condition is good. The performance of the proposed system is analyzed rigorously to derive the system outage probability and the average packet delay. Furthermore, a power allocation optimization problem to minimize the outage probability is formulated and solution to this problem is also provided in this paper. Monte Carlo simulations are conducted to verify the analytical results, which confirms that with the data buffer at the relay, the overall outage probability (OOP) has been reduced significantly.


2020 ◽  
Vol 24 (6) ◽  
pp. 1630-1654
Author(s):  
Mingqiang Guo ◽  
Chengde Han ◽  
Qingfeng Guan ◽  
Ying Huang ◽  
Zhong Xie

2020 ◽  
Vol 12 (3) ◽  
pp. 69-73
Author(s):  
Guiling Sun ◽  
◽  
Weijian Zhao ◽  
Ruobin Wang ◽  
Xuanjie Li

Visible light communication (VLC) has attracted people's attention due to its wide range of spectrum resources and good privacy in recent year. But research on visible light communication is mostly focused on LED materials, transfer protocol, transmission rates, etc. Lack of research that connect the visible light communications with existing communications methods. In this paper, we propose an Ethernet-visible data conversion system based on FPGA, including Ethernet interface logic, bit-width conversion logic, data buffer logic, and visible light communication transceiver logic. The proposed system achieves Ethernet and visible light access, and realizes 1000Mbps Ethernet data and 625Mbps visible light data conversion. Through buffer control, Ethernet data can be completely and reliably transmitted from high speed to low speed. By defining the structure of visible light communication frame and adding data self-recovery mechanism, data transmission has higher stability on the path of visible light. The feasibility of the system is proved by actual measurements.


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