scholarly journals Performance of multi-antenna wireless systems based on time reversal

2021 ◽  
Vol 2079 (1) ◽  
pp. 012025
Author(s):  
Aiguo Shen ◽  
Guangsong Yang ◽  
Dezhi Wei
Keyword(s):  
Information Transmission ◽  
Time Reversal ◽  
Communication System ◽  
Signal Transmission ◽  
Transmission Model ◽  
Channel Characteristics ◽  
Target User ◽  
Physical Channel ◽  
Electromagnetic Characteristics ◽  
Wireless Mobile Communication

Abstract 5G wireless mobile communication system is faced with massive equipment access, information security and effective transmission is worth paying attention to. Wireless physical layer security mainly uses encryption principle to enhance the security of information transmission, while time reversal technology combines its electromagnetic characteristics and physical channel characteristics to improve the security performance of wireless communication system. In this paper, a signal transmission model of wireless multi-antenna communication system based on time reversal cavity is proposed and white Gaussian noise is introduced. The simulation results show that the space-time focusing characteristics of time reversal cavity can make the signal energy more concentrated on the target user, which can not only effectively alleviate the communication quality problems caused by multipath effect, but also ensure the security of information transmission process.

Reconfigurable Antenna Beamforming in Device to Device Communication

2015 ◽  
Vol 740 ◽  
pp. 819-822
Author(s):  
Qing Shen ◽  
Tian Tian Guo ◽  
Yao Zhi Du
Keyword(s):  
Communication System ◽  
Signal Transmission ◽  
Cellular Communication ◽  
D2d Communication ◽  
System Capacity ◽  
Reconfigurable Antenna ◽  
Device To Device ◽  
Device To Device Communication

Device-to-Device (D2D) communication allows user devices in proximity to directly communicate with each other through reusing resources in cellular communication system. D2D improves the system capacity while it also raises some challenges on interference. This paper adopts reconfigurable antenna in D2D communication generating directional signal transmission between D2D pairs which mitigates the interference to other users. The simulations show that such scheme improve the system capacity compared to the traditional one.

Rate Compatible LDPC Codes Design for Shallow Water Acoustic Communications

2012 ◽  
Vol 198-199 ◽  
pp. 1609-1614
Author(s):  
You Gan Chen ◽  
Xiao Mei Xu ◽  
Lan Zhang
Keyword(s):  
Shallow Water ◽  
Communication System ◽  
Channel Coding ◽  
Error Control ◽  
Signal To Noise Ratio ◽  
Estimation Error ◽  
Ldpc Codes ◽  
Temporal Variations ◽  
Channel Characteristics ◽  
Wide Range

The fast temporal variations shallow water acoustic (SWA) channels need the temporal variations channel coding scheme at the acceptable cost. Hence, flexible channel coding rate, adjusted according to different ocean channel characteristics, should be desired in the design of practical error control SWA communication system. In this paper, we propose rate-compatible LDPC (RC-LDPC) codes to improve the communication system reliability for SWA communications. The proposed SWA system adopting RC-LDPC codes consists of three important preprocessing: channel state information (CSI) estimator, signal-to-noise ratio (SNR) estimator and RC-LDPC pattern. For the estimation error, we define and derive the sensitivity to imperfect CSI and imperfect SNR. Then the design of RC-LDPC codes and SWA channel profile are described. Furthermore, the RC-LDPC performance pattern is given and sensitivity to estimation error of CSI and SNR are analyzed via simulation. It is shown that RC-LDPC codes have good performances with wide range of rates in SWA channels. Finally, coding rate distributions of RC-LDPC codes in different SNR at BER below 10-4 for SWA channel are investigated.

Research on Communication Architecture of Power Terminal Access Network

2016 ◽  
Vol 851 ◽  
pp. 626-630
Author(s):  
Bao Zheng ◽  
Yang Wang ◽  
Chong Zhen
Keyword(s):  
Information Transmission ◽  
Electric Power ◽  
Rural Areas ◽  
Communication System ◽  
Urban Areas ◽  
Access Network ◽  
System Communication ◽  
Communication Architecture ◽  
Remote Areas ◽  
Terminal Equipment

With the accelerated pace of urbanization and the increasing number of power users in urban areas, increased the amount of business of urban power communication system. At the same time, the distribution of users in remote areas, such as rural areas has been reduced, which means that the business needs of power communications reduced. For the situation, We proposed a power system communication architecture based on the number of terminal equipment. The scheme will effectively improve the current situation of electric power communication terminal access network, and improve the efficiency of information transmission.

Modeling and Simulation of the Propagation Characteristics by Underground Current Field

2013 ◽  
Vol 385-386 ◽  
pp. 1568-1571
Author(s):  
Yi Dong Xu
Keyword(s):  
Mathematical Model ◽  
Signal Transmission ◽  
Signal Propagation ◽  
Underground Mines ◽  
Constant Current ◽  
Propagation Characteristics ◽  
Current Field ◽  
Channel Characteristics ◽  
Underground Communication ◽  
The Mathematical Model

It's one of the effective channels for short-distance wireless communications through stratum in underground mines on emergency communications. The geologic structure is complex in mines, in practical environments. It means there is a considerable difference in conductance property and channel characteristics. In order to realize effective communication through stratum, its necessary to explore and study underground signal transmission by establishing mathematical model of underground signal propagation characteristics based on the theory of constant current field and simulating the mathematical model with MATLAB. We established a simulation model of underground communication channel physics experiments and obtained the amplitude frequency characteristic of the channel, with which we can get the error comparison between theory and test.

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