共查询到20条相似文献,搜索用时 62 毫秒
1.
首先研究了非相干光反馈同步系统内部参数失配对系统同步性能的影响,并与相干光反馈的完全同步系统以及广义同步系统进行了比较,其次研究了非相干光反馈采用三种不同的信号调制解调方式(CSK,CMS,ACM),对三种不同频率(250 MHz,2.5GHz和12.5GHz)的信号进行了调制解调。通过MATLAB仿真实验可知,非相干光反馈混沌同步系统相对于相干光反馈完全同步系统更易于实现,同时保留了一定的对参数失配的敏感特性,从而确保了该系统比相干光反馈广义同步具有更高的安全性;在信号解调时,CSK只能解调出250MHz信号,CMS能解调出2.5GHz信号,ACM能够解调出高达12.5GHz的信号。 相似文献
2.
Performance characterization of high-bit-rate optical chaotic communication systems in a back-to-back configuration 总被引:1,自引:0,他引:1
A comparative study of three data-encoding techniques in optical chaotic communication systems is reported. The chaotic carrier is generated by a semiconductor laser subjected to optical feedback and the data are encoded on it by chaotic modulation (CM), chaotic masking (CMS), or chaotic shift keying (CSK) methods. In all cases, the receiver-which is directly connected to the transmitter-consists of a semiconductor laser similar to that of the transmitter subjected to the same optical feedback. The performance of this back to back configuration is numerically tested by calculating the Q-factor of the eye diagram of the received data for different bit rates from 1 to 20 Gb/s. The CM scheme appears to have the best performance relative to the CMS and CSK scheme, before and after filtering the residual high-frequency oscillations remaining due to nonperfect synchronization between the transmitter and receiver. Moreover, in all encoding methods, a decrease in the Q-factor is observed when the repetition bit-rate of the encoding message increases. In order to achieve as high Q-factor values as possible, a well-synchronized chaotic master-slave system is required. 相似文献
3.
Yanhua Hong Min Won Lee Paul J. Spencer P.S. Shore K.A. 《Lightwave Technology, Journal of》2009,27(22):5099-5105
Chaotic message encoding and decoding in unidirectionally coupled vertical-cavity surface-emitting lasers (VCSELs) with polarization-preserved and polarization-selected optical injection has been studied experimentally. A GHz message has been successfully encoded in the chaotic transmitter and decoded from the receiver with polarization-preserved optical injection. In contrast decoding using polarization-selected optical injection was achieved at only 330 MHz. It has also been demonstrated that GHz message extraction can be achieved using both normal and inverse chaos synchronization thus providing an opportunity for exploiting polarization properties of VCSELs for duplexed chaotic message transmission. 相似文献
4.
In this letter, we numerically show that chaos shift-keying (CSK) encryption can be achieved by using a single receiver, thus providing a better performance when comparing with the traditional CSK scheme based on two receivers. We analyze the rate equation model for two unidirectionally coupled single-mode external-cavity semiconductor lasers operating in a chaotic regime. The message is encoded in the emitter by slightly varying its injection current. We find that under appropriate conditions, the receiver laser synchronizes to the chaotic emitter, filtering the encoded message and allowing message extraction 相似文献
5.
Mismatch robustness and its effects on security of chaotic optical communication system based on injection-locking chaos synchronization are studied numerically by establishing the corresponding SIMULINK model. Unlike previous studies, we focus on the communication relating issues when parameter mismatches are considered. The mismatch robustness of generalized synchronization is discussed firstly in terms of cross-correlation coefficient and synchronization error. Decoding performances as well as the effects of message strength are examined for both with and without mismatch cases. Effects of injection strength on system decoding performances are also investigated by examining the chaos-pass filtering effect. Finally, a modified decoding scheme is brought forward to improve the system decoding capability. Results show that the system under consideration exhibits unconspicuous difference in both synchronization and decoding characteristics when large parameter mismatches are considered. The system based on injection-locking chaos synchronization is inappropriate for the applications where high transmission security is necessary. 相似文献
6.
MA Jun-shan GU Wen-hua 《光电子快报》2006,2(3):192-194
Chaotic communicationis of great interest because ofa potential applications in secure communications andspread spectrumcommunications .Asemiconductor lasersubject to optical feedback is known to have complexdynamic behavior ,and it can produce chaotic wa… 相似文献
7.
Kanakidis D. Bogris A. Argyris A. Syvridis D. 《Lightwave Technology, Journal of》2004,22(10):2256-2263
A detailed numerical investigation of the transmission properties of all-optical chaotic communication systems is presented for two data-encoding techniques and for various dispersion compensation maps. A semiconductor laser subjected to optical feedback generates the chaotic carrier, and the data is encoded on it by chaotic modulation (CM) or chaotic-shift-keying (CSK) methods. The complete transmission module consists of different types of fiber, inline amplifiers, and Gaussian optical filters. Different dispersion maps based on either Nonzero dispersion-shifted fibers (NZ-DSFs) or combinations of single-mode fibers (SMF) along with dispersion-compensating fibers (DCF) were considered. The system's performance is numerically tested by calculating the Q factor of the eye diagram of the received data for 1 and 2.4 Gb/s. The influence of the optical power launched into fiber and the transmission distance to the quality of the decoded message has been investigated. The CSK scheme appears to have better performance relative to the CM scheme, while dispersion maps utilizing NZ-DSFs are superior to that employing DCF. In all encoding methods and transmission maps, a decrease in the Q factor is observed when the repetition bit rate of the encoding message and the transmission distance increases. 相似文献
8.
Synchronized chaotic optical communications at high bit rates 总被引:7,自引:0,他引:7
Jia-ming Liu How-foo Chen Shuo Tang 《Quantum Electronics, IEEE Journal of》2002,38(9):1184-1196
Basic issues regarding synchronized chaotic optical communications at high bit rates using semiconductor lasers are considered. Recent experimental results on broadband, high-frequency, phase-locked chaos synchronization, and message encoding-decoding at 2.5 Gb/s are presented. System performance at a bit rate of 10 Gb/s is numerically studied for the application of three encryption schemes, namely chaos shift keying, chaos masking, and additive chaos modulation, to three chaotic semiconductor laser systems, namely the optical injection system, the optical feedback system, and the optoelectronic feedback system. By causing synchronization error in the forms of synchronization deviation and desynchronization bursts, the channel noise and the laser noise both have significant effects on the system performance at high bit rates. Among the three laser systems, the optoelectronic feedback system has the best performance while the optical feedback system has the worst. Among the three encryption schemes, only the performance of additive chaos modulation with low-noise lasers is acceptable at high bit rates. 相似文献
9.
该文研究应用粒子滤波器实现混沌通信的问题。组合信号建模技术,提出了一种基于粒子滤波器的实现方法。在发送端,采用加性混沌掩盖或乘性混沌掩盖将信息符号调制在混沌信号上;在接收端,应用粒子滤波器估计信息符号,进而实现混沌通信。仿真结果表明,当信息符号为二进制编码和M进制编码时,基于两种混沌掩盖的通信方案,粒子滤波器均能较好地从噪声混沌信号中恢复信息的编码值;与无先导卡尔曼滤波器相比,前者具有较低的误码率。此外,对比两种混沌通信方案,基于粒子滤波器的加性混沌掩盖通信系统在较高的Eb/N0下的通信性能接近BPSK,具有较低的误码率。 相似文献
10.
为了研究多信道全光混沌通信系统中信道串扰对系统同步及解码性能的影响,构建了基于垂直腔面发射激光器的多信道混沌通信系统模型.通过利用描述其特性的数率方程模型,采用相似指数作为参考标准来评价同步性能,并进行了2.5Gbit/s混沌掩藏方式的编解码数值模拟.结果表明,相对注入强度越小,信道间隔越大,系统同步的性能越好;双信道系统的同步质量相比主从式单信道系统会有明显下降,而进一步增加信道数量,同步品质并不发生显著改变.在同步质量足够高时,信号可以得到较好的恢复. 相似文献
11.
Performance characterization of a closed-loop chaotic communication system including fiber transmission in dispersion shifted fibers 总被引:1,自引:0,他引:1
Bogris A. Kanakidis D. Argyris A. Syvridis D. 《Quantum Electronics, IEEE Journal of》2004,40(9):1326-1336
The transmission performance of an all-optical closed-loop chaotic communication system is numerically studied, assuming various span lengths of dispersion shifted fiber between transmitter and receiver. Calculation of the mean synchronization error and Q-factor values obtained from the corresponding eye diagrams has been carried out for two encoding methods (chaotic modulation and chaos shift keying) and two repetition rates (2.4 and 5 Gbps). It is shown that transmission impairments including chromatic dispersion, fiber nonlinearity, fiber losses, and amplified spontaneous emission noise of the inline amplifiers degrade significantly the synchronization quality especially when high-bit-rate message encoding is applied. The influence of key system parameters such as launched optical power, amplifier spacing, positive or negative dispersion, etc., to the transmission performance has been investigated. Acceptable system performance can be achieved for approximately 200 km at 2.4 Gbps. 相似文献
12.
Chaos synchronization and chaotic signal masking in semiconductor lasers with optical feedback 总被引:7,自引:0,他引:7
Theoretical and experimental investigations of chaos synchronization and its application to chaotic data transmissions in semiconductor lasers with optical feedback are presented. Two schemes of chaos synchronization-complete and generalized synchronization-are discussed in the delay differential systems. The conditions for chaos synchronization in the systems and the robustness for the parameter mismatches are studied. The possibility of secure communications based on the chaos masking technique in semiconductor lasers with optical feedback is also discussed, and message transmission of a 1.5-GHz sinusoidal signal is demonstrated. The method of bandwidth enhancement of chaotic carriers is proposed for broad-band chaos communications. 相似文献
13.
14.
《Quantum Electronics, IEEE Journal of》2008,44(11):1089-1095
15.
Synchronization of chaotic external-cavity diode lasers has been studied in a master-slave configuration. A message is encoded into the chaotic master laser by amplitude modulation and transmitted to the slave laser. A scheme for decoding the message at the slave is demonstrated 相似文献
16.
In this paper we introduce a method for improving the performance of noncoherent chaos-based communication systems. This method
involves transforming chaotic
signals into predefined patterns according to the relative magnitudes of the signal samples.
First, for large spreading factors, the transformation leads to a large correlation between
two different chaotic signals having the same distribution. This property can be used to
recover the information in a noncoherent system. If the chaotic map and the transformation
function are known, we can generate another chaotic signal to construct the reference signal
for use in the correlator. In this scheme, both the synchronization circuit and the referencetransmission are not required.
This scheme is referred to as the near-optimal noncoherent (NON) scheme. Second, for small spreading factors where high autocorrelation
of the transmitted signals cannot be achieved, we propose a near-optimal noncoherent scheme with transmitted reference (NON-TR).
For comparison, the corresponding performance bound using coherent detection is also given. This reference scheme is called
the nearoptimal coherent (NOC) scheme. It can be shown that the NON scheme can achieve a
similar performance as the chaos shift keying (CSK) system. 相似文献
17.
YAN Sen-lin 《光电子快报》2007,3(5):363-367
Chaotic synchronization of injected multiple-quantum-well lasers of optical fiber system and a theoretical model of optical fiber chaotic secure communication system are presented by coupling a chaotic multiple-quantum-well laser synchroniza- tion system and a fiber channel. A new chaotic encoding method of chaos phase shift keying On/Off is proposed for optical fiber secure communications. Chaotic synchronization is achieved numerically in long-haul fiber system at wavelength 1.55 μm. The effect of the nonlinear-phase of fiber is analyzed on chaotic signal and synchronization. A sinusoidal signal of 0.2 GHz frequency is simulated numerically with chaos masking in long-haul fiber analog communication at wavelength 1.55 μm while a digital signal of 0.5 Gbit/s bit rate is simulated numerically with c1haos masking and a rate of 0.05 Gbit/s are also simulated numerically with chaos shift keying and chaos phase shift keying On/Off in long-haul fiber digital communica- tions at wavelength 1.55 μm 相似文献
18.
《Quantum Electronics, IEEE Journal of》2010,46(2):258-264
19.
Messages are generally selected with the same probability in the encoding scheme of rateless codes for equal error protection. In addition, a belief propagation (BP) decoding scheme is generally used because of the low computational complexity. However, the probability of recovering a new message by BP decoding is reduced if both the recovered and unrecovered messages are selected uniformly. Thus, more codeword symbols than expected are required for the perfect recovery of message symbols. Therefore, a new encoding scheme with a nonuniform selection of messages is proposed in this paper. In addition, a BP‐Gaussian elimination hybrid decoding scheme that complements the drawback of the BP decoding scheme is proposed. The performances of the proposed schemes are analyzed and compared with those of the conventional schemes. 相似文献
20.
该文分析了现有各类混沌保密通信技术的基本原理及其特点,并分别介绍了一些有实用价值的典型结构,比较了它们各自在实际应用中的性能和不足。在此基础上,提出了一种基于混沌驱动的零动态可逆离散非线性混沌通信系统。重点模拟分析了该系统的安全可靠性,防信息攻击能力,以及抗信道噪声干扰性能等,并指出了系统同步的必要性和解决途径。 相似文献