结合实际案例谈信号干扰器的危害与整治

本文结合近期查处的无线电信号干扰器案例,对所查获的干扰器的技术参数进行了分析,总结了干扰器的危害、发展趋势及排查方法,并提出了相关宣传及整治思路。

LTE信号抗干扰性能的研究

通过干扰LTE信号可以阻断LTE系统正常通信,从而防止通信信息被非法用户截获。本文简单介绍了一种常用的信号干扰方式——噪声压制式干扰,主要研究了同步信号、PBCH信道以及PCFICH信道的抗干扰性能。

Simulation of Dynamic Electromagnetic Interference Environment for Unmanned Aerial Vehicle Data Link

In order to test the anti-interference ability of an Unmanned Aerial Vehicle(UAV) data link in a complex electromagnetic environment,a method for simulating the dynamic electromagnetic interference of an indoor wireless environment is proposed.This method can estimate the relational degree between the actual face of an UAV data link in an interface environment and the simulation scenarios in an anechoic chamber by using the Grey Relational Analysis(GRA) theory.The dynamic drive of the microwave instrument produces a real-time corresponding interference signal and realises scene mapping.The experimental results show that the maximal correlation between the interference signal in the real scene and the angular domain of the radiation antenna in the anechoic chamber is 0.959 3.Further,the relational degree of the Signal-toInterference Ratio(SIR) of the UAV at its reception terminal indoors and in the anechoic chamber is 0.996 8,and the time of instrument drive is only approximately 10 μs.All of the above illustrates that this method can achieve a simulation close to a real field dynamic electromagnetic interference signal of an indoor UAV data link.

Secret Key Generation Based on Two-Way Randomness for TDD-SISO System

A novel secret key generation(SKG)method based on two-way randomness is proposed for TDD-SISO system.The legitimate transceivers mutually transmit their own random signal via reciprocal wireless channel,then the multiplication of transmitted and received signal is used as common randomness to generate secret keys.In quasi-static channel,the theoretical SKG rates(SKGRs)of the three SKG methods,namely wireless channel based,one-way randomness and two-way randomness,are derived and compared.Further,two practical SKG schemes based on twoway randomness,Scheme-1bit and Scheme-3bit,are completely designed and simulated.Generally,Scheme-1bit applies to low signal to noise ratio(SNR)scenarios and achieves 0.13~0.86bit/T_s SKGR and 10^(-2)~10^(-5) level secret key outage probability(SKOP),while Scheme-3bit fits high SNR situation and obtains 0.93~1.35bit/T_s SKGR and 10^(-3)~10^(-4) level SKOP.At last,the national institute of standards and technology(NIST)test is conducted to evaluate the secret key randomness(SKRD)and the test results show that both of the proposed schemes have passed the test.

Interference and Spectral Efficiency Analysis in Two-hop Cellular Network with Fixed Relays in FDD Mode

This paper presented a scheme of two-hop cellular network with fixed relay nodes (FRN). Based on this scheme, co-channel interference and signal interference ratio(SIR) received by base station(BS) and FRN were analyzed. Both the theoretical analysis and simulation results show that the SIR can be improved significantly when relays are employed in the network. The higher spectral efficiency can be obtained due to the improved two-hop link quality through the use of adaptive modulation and coding (AMC). The antenna height of FRN and the cell radius of BS and that of FRN influence SIR received by BS and FRN and the system spectral efficiency greatly. The proper antenna height of FRN and cell radius of BS and that of FRN were also given to get the highest spectral efficiency.

Detecting hydrosonic signal using a polarization technique

Some optical fiber hydrophones, such as PGC Mach-Zehnder Interferometer, have a birefringence of single mode optical fibers which induce signal fading. Especially, if two optical beams from the optical arms are orthogonal, the interferomic signal can’t be detected at all. Here a new method is introduced. This is to translate the detected phase difference into a linearly polarized angle, then detect it, so that polarization inducing signal fading will be avoided. In theory, this problem is solved. Furthermore, the effect on measurement results from optical source fluctuation becomes little when using the polarization technique.

Probability density analysis of SINR in massive MIMO systems with matched filter beamformer

This paper derives an approximate formula for probability density function(PDF) of received signal-to-interference-and-noise ratio(SINR) at user terminal when matched filter(MF) is adopted at a base station(BS).This distribution of SINR can be used to make an analysis of average sum-rate,outage probability,and symbol error rate of massive MIMO downlink with MF at BS.From simulation,it is found that the derived approximate analytical expression for PDF of SINR is consistent with the simulated exact PDF from the definition of SINR in medium-scale and large-scale MIMO systems.

Duplexer Design for Full-Duplex Based Wireless Communications

The full-duplex(FD) based wireless communication devices,which are capable of concurrently transmitting and receiving signals with a single frequency band,suffer from a severe self-interference(SI) due to the large power difference between the devices' own transmission and the useful signal comes from the remote transmitters. To enable the practical FD devices to be implementable,the SI power must be sufficiently suppressed to the level of background noise power,making the received signal-to-interference-plus-noise ratio(SINR) satisfy the decoding requirement. In this paper,the design and implementation of the duplexer for facilitating SI cancellation in FD based wireless communications are investigated,with a new type of duplexer(i.e. an improved directional coupler) designed for improving the spatial suppression of the SI power. Furthermore,the practical circuit boards are designed and verified for the proposed prototype,showing that the spatial suppression capability may be up to 36 d B(i.e. much higher than that attainable in the commonly designed ferrite circulator) by using the proposed design.