scholarly journals Polarization Filtering and WFRFT-Based Secure Transmission Scheme for Wireless Communications

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Zhangkai Luo ◽  
Zhongmin Pei ◽  
Xinmin Wang ◽  
Yinan Li ◽  
Bo Zou
Keyword(s):  
Wireless Communications ◽  
Fractional Fourier Transform ◽  
Polarization State ◽  
Orthogonal Polarization ◽  
Transmission Scheme ◽  
Step Size ◽  
Small Step Size ◽  
Channel Information ◽  
Polarization Filtering ◽  
Secure Transmission

In this paper, a transmission scheme based on polarization filtering and weighted fractional Fourier transform (PF-WFRFT) is proposed to enhance the transmission security in wireless communications. Indeed, the distribution of the transmit signals processed by WFRFT can be close to Gaussian, which can significantly improve the low detection probability. However, through scanning the WFRFT order with small step size, an eavesdropper can restore a regular constellation and crack the information. To overcome the problem, in the PF-WFRFT scheme, two polarized signals with mutually orthogonal polarization state are utilized to convey the information, which are processed by WFRFT separately and added up linearly before being transmitted by dual-polarized antennas. In this manner, even by scanning the WFRFT order, recovered signals are composite ones, which make the WFRFT order and the signals’ PSs difficult to crack, thus improving the security. In addition, the polarization-dependent loss (PDL) effect on the proposed scheme is discussed and a proprocessing matrix based on the channel information is constructed to eliminate this effect. Finally, numerical results are given to demonstrate the security performance of the proposed scheme in wireless communications.

Implicit Encryption of Timing Packet with Statistical Side Channel Coding

2014 ◽  
Vol 513-517 ◽  
pp. 1221-1226
Author(s):  
Bo Tao Zhu ◽  
Xiao Xiao Liu ◽  
Jun Steed Huang Huang ◽  
Zu Jue Chen
Keyword(s):  
Wireless Communications ◽  
Channel Coding ◽  
Ad Hoc ◽  
Side Channel ◽  
Security Issue ◽  
The Future ◽  
Future Extension ◽  
Channel Information ◽  
Precision Time ◽  
Statistical Coding

This paper proposes a statistical coding methodology using covert side channel information to solve timing packet security issue, the main purpose here is to enhance the security of the timing protocol with backward compatible capability. In wireless communications, either ad-hoc military/ industrial network, or LTE/ LTE-A networks, GPS is used to provide time and location; however, the hackers often trying to spoof the signal. The alternative way of providing such signal is using protocols like IEEE1588 Precision Time Protocol (PTP); unfortunately, current timing packet is not encrypted, it can be altered by the hackers. To maintain the simplicity of such protocols, most vendors are reluctant to add encryption on top of it; nevertheless, the end customer wishes to see it. To solve this dilemma, we propose a backward compatible solution here. The basic idea is demonstrated using Matlab FFT calculation tool. The future extension using Fractional FFT is also suggested at.

scholarly journals Design and experimental analysis of dual-band polarization converting metasurface for microwave applications

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Bilawal Khan ◽  
Babar Kamal ◽  
Sadiq Ullah ◽  
Imran Khan ◽  
Jawad Ali Shah ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Polarization State ◽  
Plane Waves ◽  
Microwave Frequency ◽  
Dual Band ◽  
Orthogonal Polarization ◽  
Frequency Bands ◽  
Practical Applications ◽  
Sensor Applications ◽  
Polarized Waves

Abstract The manipulation of polarization state of electromagnetic waves is of great importance in many practical applications. In this paper, the reflection characteristics of a thin and dual-band metasurface are examined in the microwave frequency regime. The metasurface consists of a 22 × 22 element array of periodic unit cells. The geometry of the unit cell consists of three layers, including a 45° inclined dipole shape metal patch on top, which is backed by a 1.6 mm thick FR-4 substrate in the middle, and a fully reflective metallic mirror at the bottom. The proposed surface is exposed to horizontally (x) or vertically (y) polarized plane waves and the co and cross polarization reflection coefficients of the reflected waves are investigated experimentally in the 6–26 GHz frequency range. The metasurface is designed to convert incident waves of known polarization state (horizontal or vertical) to orthogonal polarization state (vertical and horizontal) in two distinct frequency bands, i.e. 7.1–8 GHz and 13.3–25.8 GHz. In these two frequency bands the simulated and experimental results are in good agreement. The polarization conversion ratio (PCR) of the surface is greater than 95% in the targeted frequency bands. A detailed parametric analysis of the metasurface is also discussed in this work and it has been estimated that the surface has the additional ability to convert linearly polarized waves to circularly polarized waves at several distinct frequencies. The proposed metasurface can be utilized in sensor applications, stealth technology, electromagnetic measurements, and antennas design.

Research on Relationship of Polarization and Rayleigh Backscatter in Bidirectional Fiber Communication Systems

2013 ◽  
Vol 312 ◽  
pp. 625-630
Author(s):  
Yan Hong Wang ◽  
Gao Wang ◽  
Ji Liu
Keyword(s):  
Communication Systems ◽  
Polarization State ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Light Polarization ◽  
Polarization Property ◽  
Orthogonal Polarization ◽  
Fiber Communication ◽  
Order Of Magnitude ◽  
Relationship Of

In this paper, the general theory and polarization property of RB in single mode fiber is discussed. According to the theoretical analysis results, the bidirectional carrying system with a polarization rotating device for analog radio frequency (RF) signal is set up. The relationship of the system CRN and the different polarization state by the polarization rotating device is studied. The results show that the RB light polarization state of backward fiber end can keep to perpendicular to that of forward light when backward lights polarization is orthogonal forward lights polarization. So utilizing orthogonal polarization method for decreasing CRN can be carried on. The system performance is analyzed by simulation. The simulation results show that CRN of the bidirectional communication system on a single mode fiber can be inhibited by using the method and RB light can decrease by an order of magnitude.

Sign in / Sign up

Export Citation Format

Share Document