Partial-band Noise Jamming Research Articles

Способ повышения помехоустойчивости радиолинии связи в условиях деструктивного воздействия преднамеренных помех

The evaluation of noise immunity of reception of DPSK signals in the mode of frequency hopping spread spectrum (FHSS) for unmanned aerial vehicle (UAV) command and control radio links under the influence of narrowband noise interference (partial-band noise jamming) is performed. It is shown that the noise immunity of data transmission for UAVs under conditions of destructive noise interference can be improved by applying the mode of intra-symbol FHSS with the implementation of an algorithm for weighted signal processing to receive these signals. By the method of mathematical modeling it is shown that the work in the mode of FHSS with switching off of channels strongly affected by intentional interference allows to provide a more significant increase in the noise immunity of data transmission for the UAV communication radio links.

Эффективность применения помехоустойчивого кодирования в системах передачи цифровой информации с широкополосными сигналами.

The method of transmitting information using broadband signals is recognized as an effective way to combat various types of organized intentional and unintentional interference. Among them, methods for transmitting digital information with frequency-hopping spread spectrum (FHSS) have found wide application. Due to its frequency and energy efficiency, the transmission method with frequency hopping is widely used in information transmission systems for various purposes, including military radio communication systems (RCS), where high interference immunity is required. Both when transmitting digital information under the conditions of the destructive effect of electronic suppression means, and without this effect, the received data sequence contains errors. To detect and correct them, noise-correcting coding is effective. The article considers the case when at the input of the receiver, in addition to its own noise, there is also a deliberate concentrated partial-band noise jamming, occupied by the RCS. An analysis is made of the noise immunity of a RCS with a frequency hopping and DBPSK with the combined use of error-correcting coding and time-frequency diversity of the code symbol. The application in the analyzed RCS of the algorithm of incoherent reception of diversity signals with weight processing and subsequent decoding is considered. It’s shown that the noise immunity of the RCS under the considered conditions turns out to be significantly higher than the RCS, in which the frequency diversity of the code symbol and the noise-immune coding are not used.

Modeling and Analysis of Chaos-based Spread Spectrum Scheme using Irregular LDPC Code and Non-Coherent 16-DCSK under Fading and Jamming

In chaos-based spread spectrum systems, the use of spreading code and chaotic binary sequence expands the bandwidth of the information-bearing signal but this expansion results in SNR degradation under the constraint of constant channel capacity according to Hartley-Shannon law. To compensate for this drawback, our proposed model employs an irregular low-density parity-check (LDPC) code with its iterative decoding algorithm. Coupled with this forward error correction (FEC) coding, we used non-coherent (NC) 16-ary differential chaos shift keying (16-DCSK) that additionally provides the ability of data encryption due to its use of chaotic signals compared with the conventional modulation schemes. Analytical expressions of bit error probability (BEP) are derived under the assumption of the three-ray model along with partial band noise jamming (PBNJ) over a Rayleigh fading channel. Simulation results assert that the proposed system can mitigate the effect of PBNJ via lowering BEP by coding gain and processing gain under identical transmission power. It is also confirmed that a higher level of security can be provided by the use of proposed two iteration functions of Duffing Map-based chaotic binary sequence than the security level of one iteration function of Logistic Map, based on the balance and autocorrelation analysis.

F distribution in FFH/binary FSK system with dividing combining receiver

Fast frequency hopping (FFH) is a useful anti-jamming method. Many diversity combining methods are used to combat partial-band interference in FFH systems, including linear and non-linear combining receivers. In fifth-generation scenarios, FFH technique may take an important role in OFDM mode. In early works, a non-linear combining receiver in FFH/binary FSK system named division-combining receiver (DCR) was proposed. It was found that the random variables for decision in the DCR are F-distributed under partial-band noise jamming over additive white Gaussian noise channel, which could be used for performance analysis and the probability computation of bit error. In this Letter, the specific presentations of DCR and its F-distribution characteristics are investigated. Simulations show that DCR receiver has a light advantage among non-linear receivers.

Performance Analysis of FFH/MFSK Using Division Combining Receiver in GPS System

In this paper, a new kind of nonlinear combining receiver of fast frequency hopping/multiple frequency shift keying (FFH/MFSK) modulation in GPS system is proposed. The performance of the receiver is analyzed in the effects of partial band noise jamming over additive white Gaussian noise channel and Ricean fading channel. The diversity of the system is performed using multiple hops per data bit. The non-central F distribution is found in the random variable of the division combining algorithm under the partial-band noise jamming in the additive white Gaussian noise channel. The mathematical results of the bit error ratio of the division combining system are achieved in both fading and non-fading channels. The numerical results are achieved by the simulation environment of the signal transmission while the signal to noise ratio was relatively small and the partial band noise jamming factor is relatively large. It was shown that the GPS system using division combining receiver has better performance under the strong partial band interference than the system without diversity and system with self-normalized combining receiver. This performance gain is because that the interference signal is scattered into several hops and partly diminished by the operation of division algorithm. As its simple structure to be implemented and anti-interference property, the proposed combining algorithm is useful for GPS signal transmission in the strong partial band noise jamming environment.

부분대역 재밍 채널에서 도약 타이밍 미세 동기획득 알고리즘 성능 분석

부분대역 재밍 채널에서 도약 타이밍 미세 동기획득 알고리즘 성능 분석

Improved FH acquisition scheme in partial-band noise jamming [Correspondence

Improved FH acquisition scheme in partial-band noise jamming [Correspondence

Noise-Jamming Effect as a Countermeasure Against TEMPEST During High-Speed Signaling

With digital devices, critical information can be left unsecured due to unintentional emissions from high-speed serial interfaces, such as digital visual interface, high-definition multimedia interface, universal serial bus, and mobile high-definition link. This study presents an analysis of the effectiveness of jamming to offset unwanted information leakage by means of transient electromagnetic pulse emanation surveillance technology from differential signal lines. For a quantitative analysis, a simplified simulation methodology is used to determine the reconstruction rate of the original digital signal as a function of the signal-to-noise ratio of the detected signal for various noise power levels. In addition, the effect of more realistic partial band-noise jamming is studied. It is shown that a jamming signal with a bandwidth ranging from 350 MHz to 3 GHz and with a relatively low level of power can effectively suppress the recovery of information obtained through radio frequency information emanation. This study shows that the band-noise-jamming method using correlated noise with a wide bandwidth is also useful as a countermeasure when considered within the electromagnetic compatibility limitations.

A Subset-Based Coherent FFH System

Fast frequency hopping (FFH) is a powerful antijamming method. Nevertheless, channel estimation in FFH is a difficult issue and even once was deemed impractical. FFH over fading channels usually adopts noncoherent schemes that suffer from combination loss and low spectral efficiency. To address these issues, in this letter, we propose a subset-based coherent FFH (S-CFFH) scheme. The proposed scheme partitions the hopping frequency set into a number of subsets. By controlling the size of hopping frequency subset, we ensure that each hopped frequency recurs within the channel coherence time, which thus enables efficient channel estimation and coherent schemes. We analyze the bit error ratio (BER) of S-CFFH/quaternary phase-shift keying in the presence of partial band noise jamming, highly frequency-selective Rayleigh fading, and channel estimation errors. We further study how to optimize the S-CFFH parameters. Closed-form expressions are provided for the BER and optimum pilot parameter. Simulation results are presented to corroborate our theoretical analysis. It is shown that S-CFFH significantly outperforms conventional noncoherent FFH in both BER and spectral efficiency.

Adaptive Jamming Suppression in Coherent FFH System Using Weighted Equal Gain Combining Receiver over Fading Channels with Imperfect CSI

Fast frequency hopping (FFH) is commonly used as an antijamming communication method. In this paper, we propose efficient adaptive jamming suppression schemes for binary phase shift keying (BPSK) based coherent FFH system, namely, weighted equal gain combining (W-EGC) with the optimum and suboptimum weighting coefficient. We analyze the bit error ratio (BER) of EGC and W-EGC receivers with partial band noise jamming (PBNJ), frequency selective Rayleigh fading, and channel estimation errors. Particularly, closed-form BER expressions are presented with diversity order two. Our analysis is verified by simulations. It is shown that W-EGC receivers significantly outperform EGC. As compared to the maximum likelihood (ML) receiver in conventional noncoherent frequency shift keying (FSK) based FFH, coherent FFH/BPSK W-EGC receivers also show significant advantages in terms of BER. Moreover, W-EGC receivers greatly reduce the hostile jammers’ jamming efficiency.

Performance analysis of FFH/BPSK system with partial band noise jamming and channel estimation error in high-mobility wireless communication scenarios

In this paper, we analyze the bit error ratio (BER) of fast frequency hopping (FFH) system with binary phase shift keying (BPSK) in high-mobility wireless channels. By taking into account partial band noise jamming and channel estimation errors as Gaussian noise, both of maximal-ratio combining (MRC) and equal-gain combining (EGC) schemes are considered, and exact analytical BER expressions for MRC and EGC schemes are obtained. Especially, a closed-form BER expression for the MRC scheme is also presented in high signal-to-noise ratio region. Analytical and simulation results demonstrate that, the FFH/BPSK schemes suffer from performance degradation in the presence of channel estimation errors. The worst case jamming factor is shown to be inversely proportional to the signal to jamming ratio. With properly designed frequency hopping schemes and channel estimation schemes, the performance improvement is also observed as compared with the traditional noncoherent FFH/BFSK system.

Analysis on Ranging and Velocity Measurement Performance of DS/FH Hybrid Spread Spectrum Signal

The measurement performance with the interference is presented with the new DS/FH hybrid spread spectrum signal system. The DS/FH system model is established. The change of the SNR ratio is obtained by analyzing the characteristics of three kinds of interference signal such as partial-band noise jamming (PBNJ), wide-band noise jamming (WBNJ) and additive white Gaussian noise (AWGN). Then the ranging and velocity measurement performance is got through the simulation.

跳频通信系统抗干扰性能仿真与分析

跳频通信是军事通信的主要手段之一，因此在复杂的通信环境下保证跳频通信系统的正常工作就变得十分重要。文章首先介绍了跳频系统，并给出了跳频系统整体仿真图。其次分析了跳频系统中常见的几种干扰，主要包括：宽带噪声干扰、部分频带噪声干扰及跟踪式干扰。根据各个干扰的干扰机制及特点，利用Simulink软件对各种干扰类型进行仿真建模。最后通过将各干扰信号加入已搭建好的跳频通信系统模型中得到不同类型干扰下系统的误码率曲线。通过仿真得到的数据与误码率曲线图，分析跳频通信系统对抗各干扰的能力，总结并提出了相应的改进措施。 Frequency-hopping communication is a main means of military communication, so it is very important to guarantee the normal work of this system in the complex communication environment. First, this paper introduces the theory of Frequency-hopping communication and the simulation of this system. Then, it analyses several common types of jamming in frequency-hopping communication, including broadband noise jamming, partial band noise jamming and tracking jamming. According to the pattern and feature of different jamming, it simulates different types of jamming by using Simulink software. At last, it gets the Bit Error Rate (BER) carves of system in different types of jamming by adding interference noises into the frequency-hopping communication system which has been set up. With the getting data and the BER carves, it analyses the anti-jamming ability of frequency hopping communication system under different types of jamming, summarizes and proposes some improved methods.

Jamming Rejection Using FFH/MFSK ML Receiver Over Fading Channels With the Presence of Timing and Frequency Offsets

The composite effect of hostile multitone jamming and partial-band noise jamming on bit-error rate (BER) performance of a fast frequency-hopped M-ary frequency-shift-keying system is studied over Rayleigh fading channels in the presence of timing and frequency offsets. The maximum-likelihood (ML) diversity-combining method is employed to improve BER performance of the system. Analytical BER expression of the proposed ML receiver is derived. The analytical results, validated by computer simulation, show that the proposed ML receiver can suppress the composite hostile jamming more effectively than some existing conventional diversity-combining receivers. The ML receiver is also found to be robust against inaccurate estimation of the required side information.

Performance analysis of a suboptimum fast frequency-hopped/ M -ary frequency-shift-keying maximum-likelihood receiver over Rician-fading channels with composite effects of partial-band noise jamming and multitone jamming

Bit-error rate (BER) expressions of a suboptimum maximum-likelihood (ML) receiver with the composite effect of partial-band noise jamming and multitone jamming are derived for fast frequency-hopped systems employing M-ary frequency-shift-keying modulation over Rician-fading channels. These BER expressions can be used to study the system performance under Rayleigh fading as a special case. Owing to the fact that the computation of the logarithm of the modified Bessel function is non-linear in nature, one of the existing approximations is required to derive the BER expressions for the analysed system. A suboptimum ML receiver structure is therefore proposed and analysed. The analytical results are compared with simulation results. Under various jamming and fading conditions, the proposed suboptimum ML receiver is found to be able to suppress interference effectively.

Maximum-Likelihood FFH/MFSK Receiver over Rayleigh-Fading Channels with Composite Effects of MTJ and PBNJ

A maximum-likelihood (ML) receiver structure is proposed for fast frequency-hopped M-ary frequency-shift keying communication systems over Rayleigh-fading channels with the composite effects of multitone jamming (MTJ) and partial-band noise jamming (PBNJ). The corresponding semi-analytical bit-error rate (BER) expressions of the proposed ML receiver are also presented and validated by simulation results. Numerical results show that the BER performance with both MTJ and PBNJ is bounded by the two extreme cases, where only MTJ or PBNJ is present. It is also found that the proposed ML receiver can better counteract MTJ than PBNJ.

Jamming 환경에서 SFH 변조 방식에 따른 위성 통신 시스템의 BER 성능 분석

FHSS(Frequency Hopping Spread Spectrum) 방식은 군 통신 시스템에서 재밍(Jamming)에 의한 간섭을 줄이기 위해 사용된다. 하지만 사용되는 변조 방식의 종류, 재밍 신호의 특성에 따른 위성 통신 시스템의 BER 성능이 무선 채널 상태에 따라 어떤 성능 차이를 보이는지 분석되지 않았다. 따라서 본 논문에서는 PBNJ(Partial-Band Noise Jamming)와 WPBJ(Worst case Partial-Band noise Jamming)의 두 가지 재밍 환경에서 NC-MFSK(Non-Coherent M-ary Frequeency-Shift Keying), SDPSK(Symmetric Differential Phase-Shift Keying), GMSK (Gaussian filtered Minimum-Shift Keying)의 세 가지 변조 방식에 따른 위성 통신 시스템의 BER 성능 변화를 분석한다. 또한, 분석된 결과를 이용하여 전송 환경에 따른 최적의 전송 방식을 제안하도록 한다. The FHSS(Frequency Hopping Spread Spectrum), in which a transmitter changes its carrier frequency according to a certain hopping pattern, is widely used in the military communication system, since it is highly resistant to deliberate Jamming. However, the difference of BER performance of satellite communication system which using the different modulation scheme and Jamming model was not studied. Thus, in this paper, we consider PBNJ(Partial-Band Noise Jamming) and WPBJ(Worst case Partial-Band noise Jamming) as Jamming models, and evaluate BER(Bit Error Rate) performances of NC-MFSK(Non-Coherent M-ary Frequency-Shift Keying), SDPSK(Symmetric Differential Phase-Shift Keying), and GMSK(Gaussian filtered Minimum-Shift Keying) modulation schemes. Based on the results, we suggest the best transmission method for each condition.

Performance analysis of a noise-normalized FFH/MFSK receiver over Rayleigh fading channels with partial-band noise jamming

Fast frequency hopping can reduce the degradation caused by interference. The performance of noise-normalized fast frequency-hopped M-ary orthogonal frequency-shift-keying (FFH/MFSK) receivers over frequency nonselective Rayleigh fading channels with partial-band noise jamming is analyzed. Instead of numerical evaluation, a closed-form error probability expression is given based on the theory of complex variables. The simulation results validate the analytical results. It is shown that there is an optimum diversity order and the system performance gets better with an increase in the modulation order.

Joint EM channel and covariance estimation with sufficient‐statistic chip combining for a SIMO MC‐CDMA anti‐jam system

AbstractJoint iterative channel and covariance estimation with sufficient‐statistic‐based chip combining is studied for the downlink of a multicarrier code division multiple access (MC‐CDMA) system operating under partial‐band noise jamming (PBNJ). To estimate the channel and AWGN‐plus‐PBNJ covariance, we apply the expectation‐maximisation (EM) algorithm which exploits the log‐likelihood ratio (LLR) from the decoder. The proposed chip combiner guarantees no loss of information in the soft output generated by the demapper. In our approach, the channel estimator or the chip combiner only requires the AWGN‐plus‐PBNJ power of each subcarrier to suppress jamming. Therefore, significant complexity reduction is achieved because the receiver does not need to estimate the jammer state information (JSI) and individual variances of the AWGN and PBNJ on each subcarrier for chip combining. Simulation results show that the sufficient‐statistic chip combiner always offers a smaller bit error rate (BER) than the minimum mean square error (MMSE) chip combiner provided that reliable estimates of the channel impulse response and noise‐plus‐jamming covariance are available. Copyright © 2010 John Wiley & Sons, Ltd.

Performance analysis of FFH/MFSK receivers with noise‐normalisation combining over Nakagami‐m fading channels with partial‐band jamming

AbstractThe performance of a fast frequency‐hopped M‐ary orthogonal frequency‐shift‐keying (FFH/MFSK) receiver with noise‐normalisation combining over Nakagami‐m fading channels with partial‐band noise jamming and additive white Gaussian noise (AWGN) is analysed. Instead of numerical integration, a closed‐form error probability expression is obtained. The analytical results validate the simulation results. It is shown that there is an optimum diversity order and the corresponding best‐case performance is investigated. Copyright © 2010 John Wiley & Sons, Ltd.