共查询到20条相似文献,搜索用时 15 毫秒
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Mihajlo C. Stefanovic Goran T. Djordjevic Ivan B. Djordjevic Nebojsa D. Stojanovic 《International Journal of Satellite Communications and Networking》1999,17(1):37-49
The purpose of this paper is to provide the theoretical approach for determining the bit error probability in detecting a coherent quaternary phase-shift-keyed signal transmitted over a soft-limited channel in the presence of the uplink and downlink noise, as well as the noisy carrier reference signal. The uplink noise is considered in the specific way through the envelope variations and the frequency offset of the signal remitted by the satellite station having influence on the variations of the phase-locked loop parameters in the receiving ground station, consequently on the probability density function of the phase error, i.e. the average bit error probability. The downlink noise is also taken into consideration. The determined results are based on the non-linear phase-locked loop model with primary emphasis on the degradations in the system performance produced by the imperfect carrier signal extraction. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
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Mihajlo . Stefanovi Dragan Lj. Draa Aleksandra S. Panajotovi Nikola M. Sekulovi 《International Journal of Communication Systems》2010,23(2):139-150
In this paper, the performance of L‐branch selection combining receiver over correlated Weibull fading channels in the presence of correlated Weibull‐distributed cochannel interference is analyzed. Closed‐form expressions for probability density function and cumulative distribution function of the signal‐to‐interference ratio at the output of the selection combining receiver present main contribution of this paper. Numerical results are also presented to show the effects of various parameters as the fading severity, correlation and number of branches on outage probability. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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导出了采用L重最大比组合(MRC)和差分相位检测(DPD)方案的高斯最小频移键控(GMSK)卫星移动通信系统在不同信道条件下的误比特率公式,并利用实测数据给出数值计算结果。可用于分析阴影特性对卫星移动信道性能的影响并指导系统设计。 相似文献
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随着通信技术的发展,卫星通信系统面临着日益严重的干扰问题以及干扰识别技术的挑战。针对这一现状,介绍了常见的卫星干扰信号样式及卫星干扰信号的发展趋势,分别从基于特征提取的干扰识别方法、传统机器学习方法以及深度学习方法3个方面介绍了卫星干扰信号分类识别技术的研究现状,分析了其各自的优势与不足。最后对未来卫星干扰信号分类识别技术进行了展望。 相似文献
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José Mauro P. Fortes Juan Otalora Goicochea 《International Journal of Satellite Communications and Networking》2012,30(4):147-162
This paper presents a compatibility analysis involving space research service lunar mission uplink transmissions and the inter‐satellite links of non‐geostationary orbit systems operating in the 22‐GHz band. Three points differentiate this analysis from the currently available studies: (1) the mathematical model used here allows for the consideration of the time varying nature of the inclination of the Moon orbital plane; (2) besides the usual unconditional interference cumulative distribution functions, this analysis also considers the conditional cumulative distribution functions given that the victim satellite is receiving interference, important to characterize the interference affecting users that, because of their location, are most of the time using satellites, which are under interference; and (3) instead of dynamic time simulation, the analytical method in Recommendation ITU‐R S.1529 is used to determine the various cumulative distribution functions involved. Four scenarios are examined in the paper. Their main differences concern the number and location of the space research service transmitting Earth stations and the strategy under which they are active (transmitting). In all scenarios, cumulative distribution functions of the ratio I/N were determined for both the in‐band and the out‐of‐band interference cases. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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卫星相干光通信跟瞄误差对链路性能的影响 总被引:1,自引:1,他引:0
以星间相干激光通信链路的接收机相干效率为研究对象,分析了动态跟瞄误差对相干效率的影响,将相干效率引入到星间相干激光通信链路方程,推导了跟瞄误差波前失配条件下的相干光通信链路的误码率概率表达式,对卫星激光通信链路中跟瞄对准误差导致的相干效率下降、链路误码性能劣化情况进行了仿真计算。结果表明,由于跟瞄对准误差波前失配的影响,相干激光通信接收终端具有一个优化的接收孔径,在本仿真条件下,LEO-GEO星间链路动态跟瞄误差为0.5μrad时,优化接收孔径为0.5 m,链路可获得最佳误码性能。 相似文献
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We investigate the performance of BPSK and QPSK with coherent detection and matched filtering in the presence of both time and phase asynchronous cochannel interfering signals. More precisely, we analyze the role played by different channel statistics on the distribution of the decision variable at the output of the matched filter. The results show that the Gaussian approximation is accurate not only in the (obvious) case of a large number of interferers, but also when the desired signal is subject to fading, whatever the number of interferers is. For example, when the desired signal is subject to Rayleigh fading, even in the presence of only one unfaded interferer the Kullback-Leibler distance between the exact distribution of the decision variable and that obtained with the Gaussian approximation on the interference is lower than 0.01 [nats] for all cases of practical interest. 相似文献
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Vasilios K. Katsambas John D. Kanellopoulos 《International Journal of Satellite Communications and Networking》2005,23(1):77-90
In modern satellite communications, matters such as frequency congestion, transmission of dual polarized carriers and increase of the number of geostationary satellites in use, necessitate the implementation of interference analysis in neighbouring networks so as to ensure satisfactory quality of service. In this paper, a recently proposed model for the prediction of the degradation of the carrier‐to‐interference ratio due to differential rain attenuation and cross‐polarization, which is applicable only for the noise‐dominant case, has been properly modified to include the general case. The proposed model is based on the lognormal assumption for the point rainfall rate statistics and the convective raincell model. Due to complexity of the proposed analysis, some simple regression‐derived formulas have been generated forming a very useful tool for the system engineer. The elaborations of numerical results examine the influence of various parameters upon the total availability performance and the optimum utilization of the geostationary orbit. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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Riccardo De Gaudenzi Albert Guilln i Fbregas Alfanso Martinez 《International Journal of Satellite Communications and Networking》2006,24(4):261-281
This paper investigates the design of power and spectrally efficient coded modulations based on amplitude phase shift keying (APSK) modulation with application to satellite broadband communications. APSK represents an attractive modulation format for digital transmission over nonlinear satellite channels due to its power and spectral efficiency combined with its inherent robustness against nonlinear distortion. For these reasons APSK has been very recently introduced in the new standard for satellite Digital Video Broadcasting named DVB‐S2. Assuming an ideal rectangular transmission pulse, for which no nonlinear inter‐symbol interference is present and perfect pre‐compensation of the nonlinearity, we optimize the APSK constellation. In addition to the minimum distance criterion, we introduce a new optimization based on the mutual information; this new method generates an optimum constellation for each spectral efficiency. To achieve power efficiency jointly with low bit error rate (BER) floor we adopt a powerful binary serially concatenated turbo‐code coupled with optimal APSK modulations through bit‐interleaved coded modulation. We derive tight approximations on the maximum‐likelihood decoding error probability, and results are compared with computer simulations. The proposed coded modulation scheme is shown to provide a considerable performance advantage compared to current standards for satellite multimedia and broadcasting systems. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
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对于短波多载波跳频通信系统,跟踪式干扰是一种有效的干扰模式。分析了正交频分复用( OFDM)部分子信道干扰与符号误码率的关系,通过仿真获得了最佳跟踪干扰的部分时间参数,结合OFDM频谱结构与干扰频谱关系,推导了高斯信道条件下部分频带干扰和多音干扰时系统误码率,分析了短波FH/OFDM通信系统抗跟踪式干扰的误码率性能,仿真结果表明:跟踪干扰时间窗口对误码率的影响与部分频带干扰因子和信干比有关;在部分频带干扰与部分时间干扰之间,存在等效的干扰效果区域;多音干扰因子越大,系统所受影响越大,跟踪干扰时间窗口对误码率的影响与多音干扰因子和信干比有关,针对OFDM符号的多音干扰影响要远大于部分频带干扰的影响;跳频与OFDM技术的结合、提高载波跳速、减小跟踪式干扰对OFDM符号的影响,也是消除多音干扰的重要手段。 相似文献
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Giuseppe Cocco Martina Angelone Ana I. Pèrez‐Neira 《International Journal of Satellite Communications and Networking》2017,35(1):45-65
We study the applicability of soft interference cancelation in the forward link of multibeam satellite systems with focus on mobile terminals. We adopt a standard currently used in commercial satellite systems as a reference. The multibeam satellite antenna radiation diagram has been generated using a physical optics reflector model while a widely adopted channel model has been used for the land mobile satellite channel. The interference pattern has been derived using a system simulator developed by the European Space Agency. Starting from the analysis of the interference pattern, we study the application of a low‐complexity soft interference cancelation scheme for commercial applications. Our results show that, under realistic conditions, a two‐colors frequency reuse scheme can be employed while guaranteeing service availability across the coverage and keeping the complexity at the user terminals relatively low. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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In this work, we propose a novel multi‐bit/symbol spectral‐efficient optical orthogonal modulation scheme based on simultaneously modulating differential quadrature phase shift keying (DQPSK)‐polarization shift keying (PolSK) in a 16‐channel wavelength division multiplexing (WDM)‐based inter‐satellite optical wireless communication (IsOWC) system. Through numerical simulations, we demonstrate a reliable transportation of 16 × 100 Gbps information over 25 000 km of transmission range with acceptable bit error rate (BER) using the proposed system. Further, the impact of space turbulences (ie, pointing error losses) on the BER performance of the proposed IsOWC link has been evaluated using numerical simulations. The simulation results report a successful transportation of information up to 2.7 μrad receiver pointing error angle with acceptable performance. 相似文献
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5G具有先进和成熟的技术,而卫星通信具有天然优势,例如灵活提供网络无线宽带回传、大广域广播多播、安全应急类通信等,是未来移动通信的重要组成部分.文章分析了5G和卫星通信发展情况,以及融合场景与核心技术,表达了对未来发展的展望,为相关人员提供参考. 相似文献
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UWB技术在卫星通信领域推广应用的瓶颈是UWB卫星通信系统与窄带系统的互扰问题。研究了正弦调制高斯脉冲在卫星信道应用的时频域特性,提出了Ka频段UWB卫星通信信道模型,建立UWB卫星通信仿真系统,研究了UWB卫星通信系统和窄带系统在互扰条件下的误码特性,得到了影响互扰的关键因素,提出了适合卫星通信信道传输的UWB信号设计参数,论证了UWB卫星通信系统与窄带系统共享频谱的可行性。 相似文献
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Chao Ren Jian Chen Yonghong Kuo Long Yang Lu Lyu 《Wireless Communications and Mobile Computing》2016,16(17):2778-2791
Successive relaying has recently emerged as a spectral‐efficient technique for cooperative wireless communications. However, in scenarios with uncertain accuracy of instantaneous channel state information (CSI), the scope of conventional two‐path successive relaying protocol shrinks. This is due to the challenges of cancelling inter‐relay interference (IRI) and detecting signals efficiently without specific CSI. The two challenges motivate us to propose a novel double listening 3‐path successive relaying (DL3PSR) protocol to mitigate the successive relaying's dependence on accurate instantaneous CSI. We overcome the first challenge by proposing a blind IRI cancellation technique, and its effectiveness is proven. After blind IRI cancellation, the challenge of efficient signal detection is overcome by robust cooperative non‐coherent detection, which consists of exclusive OR (XOR) demodulation and joint decoding. Based on constellation mapping, XOR demodulation is designed to demodulate M‐ary phase‐shift keying symbols without instantaneous CSI. Moreover, joint forward and backward decoding strategy is proposed to improve the robustness of data detection by retrieving two independent versions of the original data. Furthermore, the detection threshold, bit error probability, and achievable rate of DL3PSR are theoretically obtained. Simulations verify that in scenarios without full knowledge of CSI, DL3PSR protocol outperforms conventional two‐path successive relaying in bit error performance and that the rate of DL3PSR is close to that of the full‐duplex relaying. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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《Optical Fiber Technology》2014,20(4):365-368
In this paper, we present an analytical study of the error performance in optically preamplified, M-ary pulse position modulation, in free-space optical communication systems with finite extinction ratios. We derive a theoretical expression for the probability of bit error and compute it numerically for different symbol sizes and extinction ratios. We also provide the power penalty due to a finite extinction ratio for both coded and uncoded systems. The study shows that, in certain cases and for a given extinction ratio, lower symbol sizes may yield an error performance similar to that achieved by higher symbol sizes. 相似文献