Throughput Analysis of Dynamic Spectrum Anti-Jamming Multiple-Access in HF Communication Systems

A multiple-access networking scheme based on the new dynamic spectrum anti-jamming system is proposed in this paper. The network consists of a center node and multiple user nodes. The center node detects spectrum holes in the operation band periodically according to the user performance target. Detected spectrum holes are allocated to users who request communication. Throughput of this networking scheme is analyzed over a high-frequency(HF) interference channel. The effect of error correction coding and spectrum hole information transmission error is discussed. Throughput of this scheme and conventional frequency-hopping multiple-access(FHMA) scheme are compared. Results show that user performance increase leads to throughput decrease, which can be offset by error correction coding. If spectrum hole information transmission is in error, the throughput is not affected much as long as the bit error rate is below 10-2. Furthermore, throughput of this scheme is obviously superior to the throughput of FHMA scheme.

Cognitive anti-jamming receiver under phase noise in high frequency bands

This paper investigates the jamming sensing performance of the simultaneous transmit and receive based cognitive anti-jamming(SCAJ) receiver impaired by phase noise in local oscillators(LO) over fading channels. Firstly, energy detection(ED)based on the jamming to noise ratio(JNR) of the high frequency bands SCAJ receiver with phase noise under different channels is analyzed. Then, the probabilities of jamming detection and false alarm in closed-form for the SCAJ receiver are derived. Finally,the modified Bayesian Cramer-Rao bound(BCRB) of jamming sensing for the SCAJ receiver is presented. Simulation results show that the performance degradation of the SCAJ system due to phase noise is more severe than that due to the channel fading in the circumstances where the signal bandwidth(BW) is kept a constant. Moreover, the signal BW has an effect on the phase noise in LO, and the jamming detection probability of the wideband SCAJ receiver with lower phase noise outperforms that of the narrowband receiver using the same center frequency. Furthermore,an accurate phase noise estimation and compensation scheme can improve the jamming detection capability of the SCAJ receiver in high frequency bands and approach to the upper bound.

Combined algorithm of acquisition and anti-jamming based on SFT

A communication and navigation receiver is required to remove hostile jamming signals and synchronize receiving signals effectively especially for satellite communication and navigation whose resources are becoming more and more limited. This paper proposes a novel signal receiving method by combining the pro- cesses of anti-jamming and synchronization to reduce the overall computationa~ complexity at the expense of slightly affecting the detection probability, which is analyzed in detail by derivations. Furthermore, this paper introduces sparse Fourier transformation （SFT） into the proposed algorithm to replace fast Fourier transfor- mation （FFT） so as to further reduce the calculation time especially in large frequency offset environments.

Space-borne antenna adaptive anti-jamming method based on gradient-genetic algorithm

A novel space-borne antenna adaptive anti-jamming method based on the genetic algorithm （GA）, which is combined with gradient-like reproduction operators is presented, to search for the best weight for pattern synthesis in radio frequency （RF）. Combined, the GA＇s the capability of the whole searching is, but not limited by selection of the initial parameter, with the gradient algorithm＇s advantage of fast searching. The proposed method requires a smaller sized initial population and lower computational complexity. Therefore, it is flexible to implement this method in the real-time systems. By using the proposed algorithm, the designer can efficiently control both main-lobe shaping and side-lobe level. Simulation results based on the spot survey data show that the algorithm proposed is efficient and feasible.

Comparison of the Radar Receiver Anti-Jamming Circuits Performance

This paper researches on some key technologies of anti-jamming of an air-borne radar receiver, the automatic testing of AGC, IAGC and multi-filtering under one million noisy pulses by the computer simulation system. The system tests the width of the jamming pulse whose width is 100% bigger, 60% bigger and 100% smaller than the Radar signal’s respectively and show the SNR curve.

TIME-VARYING AR MODELING AND ADAPTIVE IIR NOTCH FILTER FOR ANTI-JAMMING DSSS RECEIVER

Using Time-Varying AR (TVAR) model and adaptive notch filter is a new method for the non-stationary jammer suppression in Direct Sequence Spread Spectrum (DSSS). The performance of TVAR model for Instantaneous Frequency (IF) estimation will be affected by some factors such as basis functions. Focusing on this problem, the optimal basis function of TVAR model for the IF estimation of the LFM signal is obtained in this paper. Besides the depth and width of notching, the phase properties of notch filter affect the Signal-to-Interference plus-Noise Ratio (SINR) of correlation output to the narrowband jammer suppression in DSSS, in response to the problem the closed solution of correlation output SINR improvement has been derived when a single frequency jammer passes through direct IIR notch filter, and its performance has been compared with those of five coefficient FIR filters. Later, a novel method for LFM jammer suppression based on Fourier basis TVAR model and direct IIR notch filter is proposed. The simulation results show the effectiveness of the proposed method.

EFFICIENT DESIGN OF ANTI-JAMMING RATELESS CODING IN COGNITIVE OFDM

Efficient anti-jamming rateless coding based on cognitive Orthogonal Frequency Division Multiplexing (OFDM) modulation in Cognitive Radio Network (CRN) is mainly discussed. Rateless coding with small redundancy and low complexity is presented, and the optimal design methods of building rateless codes are also proposed. In CRN, anti-jamming rateless coding could recover the lost packets in parallel channels of cognitive OFDM, thus it protects Secondary Users (SUs) from the in-terference by Primary Users (PUs) efficiently. Frame Error Rate (FER) and throughput performance of SU employing anti-jamming rateless coding are analyzed in detail. Performance comparison between rateless coding and piecewise coding are also presented. It is shown that, anti-jamming rateless coding provides low FER and Word Error Rate (WER) performance with uniform sub-channel selection. Meanwhile, it is also verified that, in higher jamming rate and longer code redundancy scenario, rateless coding method could achieve better FER and throughput performance than another anti-jamming coding schemes.

Pattern recognitionbased method for radar antideceptive jamming

In order to make the effective ECCM to the deceptive jamming, especially the angle deceptive jamming, this paper establishes a signal-processing model for anti-deceptive jamming firstly, in which two feature-extracting algorithms, i.e. the statistical algorithm and the neural network （NN） algorithm are presented, then uses the RBF NN as the classitier in the processing model. Finally the two algorithms are validated and compared through some simulations.

Performance of Luby transform coded frequency hopping systems in partial-band jamming

Luby transform （LT） codes are proposed to suppress the effect of partial band noise jam- ming in frequency hopping （FH） communication systems. A decoding scheme for joint erasures of severely jammed symbols and error correction is proposed. If an uncorrectable error is detected, the receiver erases the jammed symbols and uses incremental redundancy to increase the error-correcting capability. The performance of LT codes, under power-oppressive partial band noise jamming （ PB- N J） with the additive white Gaussian noise （AWGN）, is evaluated via simulation. Even if the jam- mer spreads its high power over half of the hopping bandwidth, LT codes are shown to achieve a tar- get bit error probability of 10 -5, demonstrating their effectiveness as high-performance codes to im- prove the ability of FH systems to combat varying partial band noise jamming.

基于强化学习的STAR-RIS辅助的通信抗干扰方法

同时透射与反射可重构智能表面(STAR-RIS)技术作为6G的潜在关键技术之一,能够同时透射和反射入射信号,实现全空间覆盖。提出一种基于强化学习的STAR-RIS辅助通信抗干扰方法,利用相似动作空间平滑Q学习方法对基站发射功率、主动波束成形以及STAR-RIS的被动波束成形进行联合优化,显著增强无线传输系统的抗干扰性能。仿真结果验证提出的SQSA方法相比于Q学习算法具有更快的学习收敛速度、更好的抗干扰性能。

埕北326 A-7大位移井钻井液技术

埕北326 A-7井上部地层沉积大段易水化泥岩,沙河街组发育油泥岩和油页岩,古生界地层压力系数低,近5000 m斜井段定向过程中岩屑易沉降在下井壁形成岩屑床,定向施工中钻井液井壁稳定、井眼净化及润滑防卡技术难度大。通过使用聚胺低活度固壁防塌钻井液体系和海水无固相润滑防塌钻井液体系,辅助相应的现场钻井液维护处理工艺,施工中井壁稳定、井眼净化良好、定向顺畅,全井平均机械钻速24.86 m/h,取得了优快钻井的良好效果。

基于3,5-二溴水杨醛席夫碱镍配合物-氧化石墨烯电化学免疫传感器检测Anti-IgG含量的研究

应用物理吸附法将羊抗人IgG抗原直接固定于3,5-二溴水杨醛席夫碱镍配合物-氧化石墨烯修饰的金电极表面,制备电化学免疫传感器。采用循环伏安法和交流阻抗法对传感器进行表征,结果表明该传感器适合检测Anti-IgG浓度。同时探讨了缓冲液pH值、扫描速度、免疫反应温度、抗原与抗体配比对循环伏安峰电流的影响,结果表明在5-100mV/s扫速范围内,峰电流与扫速呈线性。孵育最优条件为25℃,h-IgG与Anti-IgG配比为1∶1。循环伏安法研究还表明Anti-IgG浓度在0.01-260μg/L范围内,线性关系良好,相关系数r^2=0.993,检出限（S/N=3）为0.006μg/L,据此建立了检测Anti-IgG浓度的新方法。

信号分子IRAK1/4在antiβ-2GPI/β2GPI复合物诱导THP-1细胞表达TF中的作用探讨

目的:探讨IRAK1和IRAK4在antiβ-2GPI/β2GPI复合物诱导单核细胞株THP-1表达组织因子(TF)中的作用。方法:利用荧光定量PCR(Real-time PCR)、TF活性试剂盒分别检测THP-1细胞表达TF mRNA及TF活性;Western blot检测anti-β2GPI/β2GPI复合物诱导THP-1细胞表达IRAK1、磷酸化-IRAK1(p-IRAK1)、IRAK4情况;观察IRAK1/4抑制物是否干预anti-β2GPI/β2GPI复合物诱导THP-1表达TF。结果:Antiβ-2GPI/β2GPI复合物(100μg/ml)诱导THP-1细胞表达TF显著增加(P<0.05 vs control);Antiβ-2GPI/β2GPI复合物(100μg/ml)刺激THP-1细胞表达IRAK1、p-IRAK1、IRAK4(蛋白)显著升高(P<0.05 vscontrol);IRAK1/4抑制物(50μmol/L)能够阻断antiβ-2GPI/β2GPI复合物(100μg/ml)诱导THP-1表达TF及IRAK1磷酸化的效应。结论:antiβ-2GPI/β2GPI复合物诱导THP-1细胞表达TF过程中,信号分子IRAK1/4被激活进而发挥重要作用。

JAM-C单抗对小鼠急性坏死性胰腺炎的抑制作用

目的:观察JAM-C单克隆抗体对小鼠急性坏死性胰腺炎(ANP)模型胰腺和全身炎症的抑制作用.方法:采用雨蛙素和脂多糖联合腹腔注射的方法建立小鼠重症急性胰腺炎模型.生理盐水对照组(NS组):小鼠给予腹腔注射无菌生理盐水(10mLkg),共注射6次,间隔1h;ANP模型组(ANP组):小鼠给予腹腔注射雨蛙素(50μgkg)6次,间隔1h,末次注射后立即给予腹腔注射内毒素(10mgkg);抗小鼠JAM-C单抗处理组(anti-JAM-CmAb组):小鼠给予腹腔注射雨蛙素(50μgkg)6次,间隔1h,在首次注射30min时,予每只小鼠腹腔内注射anti-JAM-CmAb0.3mL(300μg),末次雨蛙素注射后予腹腔内注射内毒素(10mgkg).在末次注射3h后,收集血液检测血清淀粉酶和血TNF-α浓度,并收集胰腺组织称胰腺湿质量和进行组织积分分析.结果:与ANP组小鼠比较,anti-JAM-CmAb的使用明显减轻了小鼠胰腺的水肿,炎症细胞浸润,坏死和出血,病理学评分明显降低(1.9±0.1vs2.4±0.3;1.5±0.2vs2.4±0.2;1.1±0.2vs2.0±0.2;1.0±0.2vs1.8±0.2,均P<0.05).此外,ANP组小鼠的胰腺湿质量、血清淀粉酶含量和血清TNF-α浓度明显高于NS组和anti-JAM-C组(348mg±27mgvs235mg±24mg,286mg±36mg;17985UL±1064ULvs1876UL±245UL,13870UL±988UL;628ngL±48ngLvs320ngL±23ngL,58ngL±13ngL,均P<0.05).结论:anti-JAM-CmAb能有效缓解小鼠ANP模型的胰腺炎症损伤和全身炎症反应.

三维Anti de Sitter空间中Lorentzian曲面的S_t^1×S_s^1-值光锥Gauss映射的奇点分类

利用Arnol'd的Legendrian理论,对三维Anti de Sitter空间中Lorentzian曲面进行了研究.引入光维高度函数概念研究了三维Anti de Sitter空间Lorentzian曲面的S1t×S1s-值、光锥Gauss映射的奇点,进行了奇点分类,揭示了类光Causs-kronecker曲率之间的关系;并研究了Lorentzian曲面的一些基本几何性质.

On the Construction of Deepening Anti - corruption Mechanism

It needs the foundation of system and the guarantee of organizational system for anti-corruption,but it is more necessary to build and form an effective anti-corruption mechanism,so that the anti-corruption can be really put into practice. Anti-corruption mechanism refers to a organic operation system of the interaction,interconnection and constraint between the constituent elements( parts) and elements of national anti-corruption,and as a system,anti-corruption mechanism should have the characteristics of system aticness,comprehensiveness,transparency,legalization,public participation,scientific dynam ic,and internationalism. The construction of deepening anti-corruption mechanism is the need for reconstructing the ruling legitimacy of the party and the governm ent. Adhering to the principle of treating both root causes and symptoms is necessary in the construction of anti-corruption m echanism,com bating and punishing corruption is an important part of anti-corruption,and the prevention and control of corruption is the basic project of anti-corruption. Therefore,the construction of prevention and control mechanism in the anti-corruption mechanism has a more far-reaching significance.

Jamming and spoofing interferences suppression technique for satellite navigation receiver

A satellite navigation receiver that can suppress jamming interference and spoofing interference simultaneously is designed in this paper.An anti-jamming improved constrained spacial adaptive processing algorithm in signal processing and an anti-spoofing M-estimator based extended Kalman filter algorithm in information processing are proposed respectively.Simulations of the integral designed anti-interferences satellite navigation receiver demonstrate that the designed anti-interferences receiver can suppress jamming signals efficiently (above 40 dB) and ensure the normal reception of satellite signals while satellite signals and jamming signals have the similar direction of arrival (almost 10°).The designed anti-interference receiver can effectively eliminate the influence of spoofing signals on the navigation solution accuracy and maintain high accuracy of position and velocity estimation,which improves the anti-jamming and anti-spoofing capability of the satellite navigation receiver.

Chaff Jamming Recognition of Radar

A modified chaff jamming recognition method of radar is investigated using grey relational analysis（ GRA） based on the difference in echo correlation characteristics between a complex rigid target and chaff cloud in time domain. Slice method（ SM）,a novel modeling approach,is proposed to construct an electromagnetic scattering model of chaff cloud in a scenario with slowly moving platform that is targeted. The diffusion characteristics and echo characteristics of the chaff cloud are analyzed. The GRA of a real target and chaff cloud shows that the adjacent return waves have a good correlation for the target but a weak correlation for chaff cloud. Since the correlation degree of chaff cloud＇s echo is far lower than that of a complex rigid target＇s,the chaff jamming can be identified by setting a reasonable threshold. Simulation results are presented to verify the effectiveness of this method.

A Blind Adaptive Jamming Canceller Using Antenna Array for GPS Receiver

Traditional beamformers need to know the incident angle of the desired signal leading while its abili-ty to handle interference is limited.In this paper,the constrained steer vector of linearly constrained min-imum-variance(LCMV)beamformer is modified to make sidelobe null to direction of powerful jammer.Inaddition,the state-space concept is used to describe the anti-jammer filter,and Kalman filter algorithm isdeduced by building the observation model and measurement equation.The new method is more efficient oncomputation and more robust to survive environment with large scale variation in interference strength.Fi-nally,simulation results shows that the new approach can form the null with its depth in proportion to powerin direction of jammer,and has steady convergence process.The novel method can effectively improve thesignal-to-jammer-plus-noise power ratio(SJNR)of GPS signals to make the correlation peak easy to track.

基于压缩感知的捷变雷达距离-速度估计

在目标识别探测领域,毫米波雷达发挥着至关重要的作用。其中抗干扰能力和检测精度是衡量雷达性能的两项重要指标。为提高雷达抗干扰能力,改善雷达的信号处理效果,提升雷达的距离-速度检测精度,本文采用相参处理时间(CPI)间载频捷变与脉间脉冲重复频率(PRF)捷变相结合的雷达信号,利用压缩感知(CS)模型进行频谱生成,并设计了新型雷达距离-速度分析法进行目标检测,建立了一套完整的雷达信号处理算法。对算法的各个环节进行理论分析和仿真实验,仿真结果证明,本文设计的基于压缩感知的捷变雷达距离-速度估计方法,增强了雷达的抗干扰能力,同时提升了雷达的距离-速度检测精度。