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2002 Vol. 24, No. 2
Display Method:
2002, 24(2): 145-150.
Abstract:
With XGM (Cross-Gain Modulation) technology, a type of all-optical wavelength converter can be simply made. In this paper, using a simple model, the influence of path blocking probability made by XGM wavelength converter is first analyzed, then considering the characteristic of XGM wavelength converter, three kinds of RWA(routing and wavelength assignment) are designed, which are suitable for the all-optical XGM wavelength converters. By simulating in NSFNET and Mesh-torus network, the performance improvement is assessed and the performance of the three kinds of RWA are compared. The simulation results show that significant improvement in blocking probability and fairness is obtained and the performance of FF/lowest algorithm is best among the three kinds of RWA.
With XGM (Cross-Gain Modulation) technology, a type of all-optical wavelength converter can be simply made. In this paper, using a simple model, the influence of path blocking probability made by XGM wavelength converter is first analyzed, then considering the characteristic of XGM wavelength converter, three kinds of RWA(routing and wavelength assignment) are designed, which are suitable for the all-optical XGM wavelength converters. By simulating in NSFNET and Mesh-torus network, the performance improvement is assessed and the performance of the three kinds of RWA are compared. The simulation results show that significant improvement in blocking probability and fairness is obtained and the performance of FF/lowest algorithm is best among the three kinds of RWA.
2002, 24(2): 151-157.
Abstract:
Based on a kind of short-wave FH-DQPSK system demodulating technology of FFT and according to PER estimation in the DQPSK system with Rayleigll fading channel,this paper proposes a method to estimate BER using adaptive linear extrapolation algorithm, and analyses the confidence level about this method.The numerical simulated results show that the performance of this method is superior to the estimating method without using extrapolation algorithm.
Based on a kind of short-wave FH-DQPSK system demodulating technology of FFT and according to PER estimation in the DQPSK system with Rayleigll fading channel,this paper proposes a method to estimate BER using adaptive linear extrapolation algorithm, and analyses the confidence level about this method.The numerical simulated results show that the performance of this method is superior to the estimating method without using extrapolation algorithm.
2002, 24(2): 158-163.
Abstract:
Using matrix and vector the OADM nodes of WDM optical network have been researched and analyzed roundly and completely. A kind of analyzing model of OADM is proposed and the signal performance is analyzed with the novel OADM model when it is transited in the OADM ring network. The SNR of the signal is gotten. The model is very valuable to the analysis and design of the OADMs.
Using matrix and vector the OADM nodes of WDM optical network have been researched and analyzed roundly and completely. A kind of analyzing model of OADM is proposed and the signal performance is analyzed with the novel OADM model when it is transited in the OADM ring network. The SNR of the signal is gotten. The model is very valuable to the analysis and design of the OADMs.
2002, 24(2): 164-169.
Abstract:
One novel method of Self-Test is proposed in this paper to avoid the shortcomings of the traditional testing ways for digital cross-connect systems. By implementing the self-test functions in the system, the established connect can be easily tested with no need for special testing equipment. This can greatly ease the test of connect and system and save the investment with only a little increment of systems complexity. The idea to contain the self-test function in the system would be very helpful for accelerating the development of system and also for the verifying of the products.
One novel method of Self-Test is proposed in this paper to avoid the shortcomings of the traditional testing ways for digital cross-connect systems. By implementing the self-test functions in the system, the established connect can be easily tested with no need for special testing equipment. This can greatly ease the test of connect and system and save the investment with only a little increment of systems complexity. The idea to contain the self-test function in the system would be very helpful for accelerating the development of system and also for the verifying of the products.
2002, 24(2): 170-175.
Abstract:
In this paper, a new technique for DS-CDMA signal detection is proposed. By using the orthogonally-anchored generalized sidelobe canceller structure and training sequence, fast/nonadaptive optimization is achieved based on the minimum-output-energy criterion. The output signal to interference plus noise ratio of the code matched filter is effectively applied to suppress the effect of mismatch on optimization of the despreading filter, which results in robust multi-user access interference cancellation. Furthermore, the RAKE combining technique is used to improve the performance of the receiver in Rayleigh fading channels.
In this paper, a new technique for DS-CDMA signal detection is proposed. By using the orthogonally-anchored generalized sidelobe canceller structure and training sequence, fast/nonadaptive optimization is achieved based on the minimum-output-energy criterion. The output signal to interference plus noise ratio of the code matched filter is effectively applied to suppress the effect of mismatch on optimization of the despreading filter, which results in robust multi-user access interference cancellation. Furthermore, the RAKE combining technique is used to improve the performance of the receiver in Rayleigh fading channels.
2002, 24(2): 176-183.
Abstract:
A versatile signal model suitable for linear space-time multiuser detectors in asynchronous DS-CDMA systems is proposed. Based on the model, a versatile linear space-tine multiuser detector is presented and its optimal solution according to the Liner Constrained Minimum Variance (LCMV) criterion is deduced. The analyses of the existent linear multiuser detectors demonstrate that these methods are just the special cases of the versatile detector in this paper and can only achieve the suboptimal solution. Hence their interference canceling performance is inferior to the optimal detector in this paper. Finally, numerical simulations are presented.
A versatile signal model suitable for linear space-time multiuser detectors in asynchronous DS-CDMA systems is proposed. Based on the model, a versatile linear space-tine multiuser detector is presented and its optimal solution according to the Liner Constrained Minimum Variance (LCMV) criterion is deduced. The analyses of the existent linear multiuser detectors demonstrate that these methods are just the special cases of the versatile detector in this paper and can only achieve the suboptimal solution. Hence their interference canceling performance is inferior to the optimal detector in this paper. Finally, numerical simulations are presented.
2002, 24(2): 184-191.
Abstract:
In electronic payment system, it is more suitable to introduce the distributed electronic bank scheme in networks environment. However, in current scheme, the users obtain their cards issued by the bank in which they have opened their accounts and withdraw and store their e-coin at the bank. Due to limits of current network neckbottle and security, dispersed and mobile users in different areas, there are some defects in a practical monadic account e-bank scheme. To solve this, a hierarchically distributed bank scheme is proposed by using an integrated method in which the group signature technique is combined with the proxy signature technique and analysis of the scheme security is given.
In electronic payment system, it is more suitable to introduce the distributed electronic bank scheme in networks environment. However, in current scheme, the users obtain their cards issued by the bank in which they have opened their accounts and withdraw and store their e-coin at the bank. Due to limits of current network neckbottle and security, dispersed and mobile users in different areas, there are some defects in a practical monadic account e-bank scheme. To solve this, a hierarchically distributed bank scheme is proposed by using an integrated method in which the group signature technique is combined with the proxy signature technique and analysis of the scheme security is given.
2002, 24(2): 192-197.
Abstract:
Quick trickle permutation has good cryptographic properties. In this paper, the concept of quick trickle characteristic sequence is presented, the properties and count of quick trickle characteristic sequence is presented, the mapping relation between quick trickle characteristic sequence and quick trickle permutation is discussed. Finally, a effective construction of quick trickle permutation based on quick trickle characteristic sequence is given, by which quick trickle permutation can be figured out after constructing quick trickle characteristic sequence.
Quick trickle permutation has good cryptographic properties. In this paper, the concept of quick trickle characteristic sequence is presented, the properties and count of quick trickle characteristic sequence is presented, the mapping relation between quick trickle characteristic sequence and quick trickle permutation is discussed. Finally, a effective construction of quick trickle permutation based on quick trickle characteristic sequence is given, by which quick trickle permutation can be figured out after constructing quick trickle characteristic sequence.
2002, 24(2): 198-203.
Abstract:
Since the multicomponent signal with nonlinear time-frequency structures occupies a wide frequency band, and the spectral contents of the signal components may alias, it is therefore difficult to separate the signal components and to separate the signal from background noise. In this paper, a new signal separation method using FMmlet transform is proposed taking the advantage that the atoms of FMmlet transform can match both the linear and nonlinear time-varying structures. Theoretical predictions and numerical experiments show the feasibility of the methodology advocated.
Since the multicomponent signal with nonlinear time-frequency structures occupies a wide frequency band, and the spectral contents of the signal components may alias, it is therefore difficult to separate the signal components and to separate the signal from background noise. In this paper, a new signal separation method using FMmlet transform is proposed taking the advantage that the atoms of FMmlet transform can match both the linear and nonlinear time-varying structures. Theoretical predictions and numerical experiments show the feasibility of the methodology advocated.
2002, 24(2): 204-209.
Abstract:
In this under-sampling of pass-band signal, the fractional ratio Sampling Rate Conversion(SRC) is a procedure which requires a lot of computations. The low-order linear interpolating will incur more aliase noise. Based on the polyphase filter architecture and minimum-operation principle, this paper integrates the interpolating, filtering, and decimating operations in the course of SRC, and presents three architectures for efficient conversion. It also compares the operation efficiencies of the three architectures, and finally gives the computer simulation results on a typical signal.
In this under-sampling of pass-band signal, the fractional ratio Sampling Rate Conversion(SRC) is a procedure which requires a lot of computations. The low-order linear interpolating will incur more aliase noise. Based on the polyphase filter architecture and minimum-operation principle, this paper integrates the interpolating, filtering, and decimating operations in the course of SRC, and presents three architectures for efficient conversion. It also compares the operation efficiencies of the three architectures, and finally gives the computer simulation results on a typical signal.
2002, 24(2): 210-215.
Abstract:
A new Hybrid Clustering Algorithm (HCA) that incorporates the fuzzy C-means into the canonical genetic algorithm is proposed in this paper. The HCA speeds up convergence before the genetic algorithm reach the global optima, and eliminates fuzzy C-means trapped local minima by performing global search and local search alternatively. The experiments for clustering three data sets with different distributions show that the HCA has better generalization and effectiveness.
A new Hybrid Clustering Algorithm (HCA) that incorporates the fuzzy C-means into the canonical genetic algorithm is proposed in this paper. The HCA speeds up convergence before the genetic algorithm reach the global optima, and eliminates fuzzy C-means trapped local minima by performing global search and local search alternatively. The experiments for clustering three data sets with different distributions show that the HCA has better generalization and effectiveness.
2002, 24(2): 216-221.
Abstract:
A novel method of texture-image classification in DCT compressed-domain is proposed. The textural feature; of energy-orientation is extracted in DCT transfonned-domain and this textural feature can be used to classify texture-images in RLE bit-stream directly. The experimental results demonstrate that texture-images can be classified at higher correct, classification rate under random noise.
A novel method of texture-image classification in DCT compressed-domain is proposed. The textural feature; of energy-orientation is extracted in DCT transfonned-domain and this textural feature can be used to classify texture-images in RLE bit-stream directly. The experimental results demonstrate that texture-images can be classified at higher correct, classification rate under random noise.
2002, 24(2): 222-231.
Abstract:
In this paper, slowly moving target detection for airborne fire-control radar and the effect of transmitting bandwidth are discussed. The system of this kind is often characterized by the highly ambiguous Doppler frequency of ground clutter and large Doppler bandwidth of mainbeam clutter. In this case, conventional processing can not give systems good performance of detection. Considering the actual conditions, this paper is focused on the features of detection of slowly moving targets by use of the airborne fire-control radar, and the cascade processing and joint processing are compared. Because using large transmitting bandwidth is todays trend, the effect of bandwidth on slowly moving target detection is also discussed. Finally, simulation results are included to validate the conclusions of the bandwidth effect.
In this paper, slowly moving target detection for airborne fire-control radar and the effect of transmitting bandwidth are discussed. The system of this kind is often characterized by the highly ambiguous Doppler frequency of ground clutter and large Doppler bandwidth of mainbeam clutter. In this case, conventional processing can not give systems good performance of detection. Considering the actual conditions, this paper is focused on the features of detection of slowly moving targets by use of the airborne fire-control radar, and the cascade processing and joint processing are compared. Because using large transmitting bandwidth is todays trend, the effect of bandwidth on slowly moving target detection is also discussed. Finally, simulation results are included to validate the conclusions of the bandwidth effect.
2002, 24(2): 232-237.
Abstract:
In this paper, automotive collision warning radar systems which operate on millimeter wave band is introduced first, then a new radar transmit waveform, which can be called multi-slope stepped-FMCW waveform, applied for those systems to solve the false alarm problem is proposed. The new waveform is easy to be generated digitally and its signal processing reduces the high-speed and wide-band signal processing requirement compared with conventional high resolution radar. An error approach algorithm for multiple vehicle target detection is suggested and its usefulness in eliminating the false target is confirmed by computer simulation.
In this paper, automotive collision warning radar systems which operate on millimeter wave band is introduced first, then a new radar transmit waveform, which can be called multi-slope stepped-FMCW waveform, applied for those systems to solve the false alarm problem is proposed. The new waveform is easy to be generated digitally and its signal processing reduces the high-speed and wide-band signal processing requirement compared with conventional high resolution radar. An error approach algorithm for multiple vehicle target detection is suggested and its usefulness in eliminating the false target is confirmed by computer simulation.
2002, 24(2): 238-242.
Abstract:
A new method of transmit pattern synthesis for Secondary Surveillance Radar (SSR) is presented. This method is concerned with an active phasedarray antenna. A cosine on pedestal excitation for aperture distribution is used to synthesized the desired directional pattern, which is used to transmit the P1 and P3 pulse for interrogation. Using stationary phase method, the phase function over aperture on the specified aperture amplitude distribution is obtained and the desired pattern to transmit the P2 pulse is synthesized for Interrogation Side Lobe Suppression (ISLS). The antenna and relevant equipment which transmits only the P2 pulse is saved.
A new method of transmit pattern synthesis for Secondary Surveillance Radar (SSR) is presented. This method is concerned with an active phasedarray antenna. A cosine on pedestal excitation for aperture distribution is used to synthesized the desired directional pattern, which is used to transmit the P1 and P3 pulse for interrogation. Using stationary phase method, the phase function over aperture on the specified aperture amplitude distribution is obtained and the desired pattern to transmit the P2 pulse is synthesized for Interrogation Side Lobe Suppression (ISLS). The antenna and relevant equipment which transmits only the P2 pulse is saved.
2002, 24(2): 243-249.
Abstract:
Based on the Uniform Geometric Theory of Diffraction (UTD), the scattering of aircraft including propellers for the phased-array of the main radar is analysed by using of a new additive model of antenna. The variety and characteristic of the scattering is presented quantitatively. It can be used as a theoretical basis to dope out the radiation performance and optimize the arrangement of antennas.
Based on the Uniform Geometric Theory of Diffraction (UTD), the scattering of aircraft including propellers for the phased-array of the main radar is analysed by using of a new additive model of antenna. The variety and characteristic of the scattering is presented quantitatively. It can be used as a theoretical basis to dope out the radiation performance and optimize the arrangement of antennas.
2002, 24(2): 250-256.
Abstract:
Space-time equivalence in digital design and the threshold-controllable technique arc introduced to the design of A/D converter in this paper. The proposed A/D converter has simpler structure while keeping higher speed.
Space-time equivalence in digital design and the threshold-controllable technique arc introduced to the design of A/D converter in this paper. The proposed A/D converter has simpler structure while keeping higher speed.
2002, 24(2): 257-260.
Abstract:
In DS-CDMA system with BPSK modulation, Support Vector Machine (SVM) based multiuser detection uses SVM classification method to classify received vectors into two classes. One is the received vectors of desired users symbol +1 and the other is the vectors of desired users symbol -1. So desired users symbol can be detected by this method. Different with MMSE method, SVM classifier finds the optimal separating hyperplane that separates the class of +1 and class of -1. Simulation results show that the performance of the SVM detector is better than that of MMSE detector in Rayleigh channels.
In DS-CDMA system with BPSK modulation, Support Vector Machine (SVM) based multiuser detection uses SVM classification method to classify received vectors into two classes. One is the received vectors of desired users symbol +1 and the other is the vectors of desired users symbol -1. So desired users symbol can be detected by this method. Different with MMSE method, SVM classifier finds the optimal separating hyperplane that separates the class of +1 and class of -1. Simulation results show that the performance of the SVM detector is better than that of MMSE detector in Rayleigh channels.
2002, 24(2): 261-265.
Abstract:
The power control is one of the key techniques of the upstream channel of the S-C DMA-HFC system. It is unreasonable that the acquisition CDMA terminals employ the traditional power control methods. In this paper, an improved acquisition power control algorithm is proposed. The simulation results of the throughout and the access delay are given and the performance comparison between the improved algorithm and the traditional method is provided.
The power control is one of the key techniques of the upstream channel of the S-C DMA-HFC system. It is unreasonable that the acquisition CDMA terminals employ the traditional power control methods. In this paper, an improved acquisition power control algorithm is proposed. The simulation results of the throughout and the access delay are given and the performance comparison between the improved algorithm and the traditional method is provided.
2002, 24(2): 266-271.
Abstract:
A new matrix decoding algorithm for Turbo-codes is derived from Bahl s matrix algorithm. The complex iterating operations are paralleled and well formulclted as a set of simple matrix operations which are fit to design efficient VLSI circuits. Thus, the matrix algorithm increases the decoding speed and simplifies the excessive memory accesses, and is specially fit to Turbo-codes with small memories. States transfer and decoding process of Turbo-codes in 3GPP are also discussed in this paper.
A new matrix decoding algorithm for Turbo-codes is derived from Bahl s matrix algorithm. The complex iterating operations are paralleled and well formulclted as a set of simple matrix operations which are fit to design efficient VLSI circuits. Thus, the matrix algorithm increases the decoding speed and simplifies the excessive memory accesses, and is specially fit to Turbo-codes with small memories. States transfer and decoding process of Turbo-codes in 3GPP are also discussed in this paper.
2002, 24(2): 272-275.
Abstract:
By removing redundance from oversampling Gabor transform, an improved critical sampling Gabor transform is presented where its synthesis and analysis function possess favorable local properties and regularity simultaneously, while computation complexity of Gabor coefficient as much as that of conventional critical sampling Gabor transform.
By removing redundance from oversampling Gabor transform, an improved critical sampling Gabor transform is presented where its synthesis and analysis function possess favorable local properties and regularity simultaneously, while computation complexity of Gabor coefficient as much as that of conventional critical sampling Gabor transform.
2002, 24(2): 276-279.
Abstract:
A dynamic (k,n)-threshold secret sharing scheme based on discrete logarithm is proposed in this paper. It can reconstruct the different system secrets for many times without any restriction. Any cheater can be checked out. When some participants secret sharing values are revealed, they can be renewed without any effect on the others. It is convenient to add or to delete one or more participants. The system secret can be recovered with a parallel process.
A dynamic (k,n)-threshold secret sharing scheme based on discrete logarithm is proposed in this paper. It can reconstruct the different system secrets for many times without any restriction. Any cheater can be checked out. When some participants secret sharing values are revealed, they can be renewed without any effect on the others. It is convenient to add or to delete one or more participants. The system secret can be recovered with a parallel process.
2002, 24(2): 280-284.
Abstract:
The wavelet transform is a very effective mathematical tools for many fields such as signal processing and image coding, which is implemented by program in most cases. This paper presents a novel architecture suitable with CPLD chip for one- dimension DWT decomposition based on the relationship between wavelet transform and filter banks by rearranging the data in the processing of convolution and downsample by two. It possesses some practicable value with certain speed and decreased resources.
The wavelet transform is a very effective mathematical tools for many fields such as signal processing and image coding, which is implemented by program in most cases. This paper presents a novel architecture suitable with CPLD chip for one- dimension DWT decomposition based on the relationship between wavelet transform and filter banks by rearranging the data in the processing of convolution and downsample by two. It possesses some practicable value with certain speed and decreased resources.
2002, 24(2): 285-288.
Abstract:
The 4-pole microwave filters using dual-mode meander suspensive strip line loop resonators have been developed. The results of the full wave analysis of the filters have shown that 4-pole filters have better performance than the 2-pole fiilters of same type. A 4-pole filter of this type on r= 2.8 Teflon substrate having a bandwidth △f=19.4MHz at the central frequency f0 = 1.194GHz was designed and fabricated. The measured filter performance was compared with the prediction of CAD tool. The agreement was found to be good.
The 4-pole microwave filters using dual-mode meander suspensive strip line loop resonators have been developed. The results of the full wave analysis of the filters have shown that 4-pole filters have better performance than the 2-pole fiilters of same type. A 4-pole filter of this type on r= 2.8 Teflon substrate having a bandwidth △f=19.4MHz at the central frequency f0 = 1.194GHz was designed and fabricated. The measured filter performance was compared with the prediction of CAD tool. The agreement was found to be good.
