Email alert
2005 Vol. 27, No. 8
Display Method:
2005, 27(8): 1177-1181.
Abstract:
A new algorithm named optimal matching based on spatial relationship in local regions for content-based image retrieval is proposed in this paper. The algorithm first employs the symbol mapping model to reduce a symbolic image to a l-D representation, and then uses the principle of nearest distance within equal angle region for searching nearest nodes, takes the center point for dividing images into sub-regions, and applies the breadth-first traversal algorithm in graph theory to perform graph matching. Finally, it uses the defined similar distances between local regions and among different graphs to compute the similarity and to retrieve images based on inner spatial relationship. Based on these algorithms, a prototype system for analyzing the position of players in basketball game is constructed. The effectiveness of image retrieval based on spatial relationship is verified in this system by using some real data.
A new algorithm named optimal matching based on spatial relationship in local regions for content-based image retrieval is proposed in this paper. The algorithm first employs the symbol mapping model to reduce a symbolic image to a l-D representation, and then uses the principle of nearest distance within equal angle region for searching nearest nodes, takes the center point for dividing images into sub-regions, and applies the breadth-first traversal algorithm in graph theory to perform graph matching. Finally, it uses the defined similar distances between local regions and among different graphs to compute the similarity and to retrieve images based on inner spatial relationship. Based on these algorithms, a prototype system for analyzing the position of players in basketball game is constructed. The effectiveness of image retrieval based on spatial relationship is verified in this system by using some real data.
2005, 27(8): 1182-1186.
Abstract:
The framework for image singularity analysis based on multifractal theory is presented in this paper. The measure is defined which gives the local distribution of the gradient of the image. The exponential formalism between the projection of fast decreasing functions of the defined measure and scale is proved. According to the exponential formalism, the paper also presented an algorithm, in which the nature image can be decomposed in a serial fractal sets with different singularity exponent and fractal dimension. Finally, some basic theoretical results of the choice for the fast decreasing functions are proposed. Also an investigation of how to reconstruct the different fractal image components with derivative information contained in the different fractal sets is made. Experiments show that the multifractal formalism has significance in image singularity analysis and detection.
The framework for image singularity analysis based on multifractal theory is presented in this paper. The measure is defined which gives the local distribution of the gradient of the image. The exponential formalism between the projection of fast decreasing functions of the defined measure and scale is proved. According to the exponential formalism, the paper also presented an algorithm, in which the nature image can be decomposed in a serial fractal sets with different singularity exponent and fractal dimension. Finally, some basic theoretical results of the choice for the fast decreasing functions are proposed. Also an investigation of how to reconstruct the different fractal image components with derivative information contained in the different fractal sets is made. Experiments show that the multifractal formalism has significance in image singularity analysis and detection.
2005, 27(8): 1187-1192.
Abstract:
A novel watermarking scheme to ensure the credibility of audio is proposed in this paper. Psychoacoustic model controls the wavelet packet decomposition as well as the watermark insertion in the wavelet packet domain, which enhances both the transparency and the flexibility of the algorithm. Unlike previously proposed algorithms, the presented method embeds several bits of watermark instead of just one in a single coefficient. By introducing the detecting function, the new scheme can not only authenticate the integrity of the audio signal but also locate the tampered＇region and decide to what extent the audio being tampered. Experimental results show that the proposed scheme has the desired property and can be used for applications including authentication for forensic identification and news broadcasting.
A novel watermarking scheme to ensure the credibility of audio is proposed in this paper. Psychoacoustic model controls the wavelet packet decomposition as well as the watermark insertion in the wavelet packet domain, which enhances both the transparency and the flexibility of the algorithm. Unlike previously proposed algorithms, the presented method embeds several bits of watermark instead of just one in a single coefficient. By introducing the detecting function, the new scheme can not only authenticate the integrity of the audio signal but also locate the tampered＇region and decide to what extent the audio being tampered. Experimental results show that the proposed scheme has the desired property and can be used for applications including authentication for forensic identification and news broadcasting.
2005, 27(8): 1193-1196.
Abstract:
Discrete Ambiguity Function （DAF） is used to estimate parameters of LFM signal after improving SNR based on recomposing sequences. This method does not add the number of the sampling data and ensures real-time processing, but can improve the precision of parameters estimation and reduce the need for input Signal-to-Noise Ratio（SNR） in order to estimating exactly. This paper analyses theoretically its basic principle and performance. Simulation results prove the validity of this method.
Discrete Ambiguity Function （DAF） is used to estimate parameters of LFM signal after improving SNR based on recomposing sequences. This method does not add the number of the sampling data and ensures real-time processing, but can improve the precision of parameters estimation and reduce the need for input Signal-to-Noise Ratio（SNR） in order to estimating exactly. This paper analyses theoretically its basic principle and performance. Simulation results prove the validity of this method.
2005, 27(8): 1197-1200.
Abstract:
A new method for signal subspace fitting is presented. Firstly, a novel criterion of signal subspace fitting is derived. It is shown that the correct knowledge of the number of signals is unnecessary since the columns of the signal subspace can be much lower than the number of signals. The proposed method does not resort to the estimate of the covariance matrix or its eigendecomposition, thereby implying much lower computational complexity. Finally, the effectiveness of the proposed approach is verified by numerical results.
A new method for signal subspace fitting is presented. Firstly, a novel criterion of signal subspace fitting is derived. It is shown that the correct knowledge of the number of signals is unnecessary since the columns of the signal subspace can be much lower than the number of signals. The proposed method does not resort to the estimate of the covariance matrix or its eigendecomposition, thereby implying much lower computational complexity. Finally, the effectiveness of the proposed approach is verified by numerical results.
2005, 27(8): 1201-1204.
Abstract:
According to the theory of the fractional lower order statistical signal processing and the characteristics of ship radiated noises, this paper proposes a new noise model of underwater acoustic signals. The reasons of performance degenerate are analyzed for traditional LMS approach. A new replace approach is advanced to adaptive filtering based on fractional lower order moments for underwater acoustic signals. It is analyzed how to affect the performance of LMP algorithm for choosing p value. Theoretic analysis and computer simulations indicate that the new method is not only suitable for Gaussian noise conditions, but also very robust under the lower order -stable distribution noise conditions.
According to the theory of the fractional lower order statistical signal processing and the characteristics of ship radiated noises, this paper proposes a new noise model of underwater acoustic signals. The reasons of performance degenerate are analyzed for traditional LMS approach. A new replace approach is advanced to adaptive filtering based on fractional lower order moments for underwater acoustic signals. It is analyzed how to affect the performance of LMP algorithm for choosing p value. Theoretic analysis and computer simulations indicate that the new method is not only suitable for Gaussian noise conditions, but also very robust under the lower order -stable distribution noise conditions.
2005, 27(8): 1205-1207.
Abstract:
The iterative form of the Super-Exponential （SE） algorithm has good convergence capability, but its complexity increases with the square of the equalizer length, which makes it unsuitable for hardware implementation. According to the properties of sparse underwater channels, a novel improved sparse Super-Exponential Iterative （SEI） blind equalization algorithm is proposed, which uses part of the SE algorithm to estimate the equalizer. After sparse processing, the equalizer is used to initialize the SEI algorithm. Less complexity and faster convergence rate is attainable with this method. The computer simulation results confirm the effectiveness of the proposed algorithm.
The iterative form of the Super-Exponential （SE） algorithm has good convergence capability, but its complexity increases with the square of the equalizer length, which makes it unsuitable for hardware implementation. According to the properties of sparse underwater channels, a novel improved sparse Super-Exponential Iterative （SEI） blind equalization algorithm is proposed, which uses part of the SE algorithm to estimate the equalizer. After sparse processing, the equalizer is used to initialize the SEI algorithm. Less complexity and faster convergence rate is attainable with this method. The computer simulation results confirm the effectiveness of the proposed algorithm.
2005, 27(8): 1208-1212.
Abstract:
The digital phase-locked loops design is a key technology for carrier and bit synchronization in coherent demodulation digital receiver. Large frequency offset and low SNR add more difficulties of the loop design from two different ways. Based on this condition, aim at fast acquisition and tracking, a method of digital loop parameter algorithm is proposed in this paper and some useful conclusions are given.
The digital phase-locked loops design is a key technology for carrier and bit synchronization in coherent demodulation digital receiver. Large frequency offset and low SNR add more difficulties of the loop design from two different ways. Based on this condition, aim at fast acquisition and tracking, a method of digital loop parameter algorithm is proposed in this paper and some useful conclusions are given.
2005, 27(8): 1213-1216.
Abstract:
Estimation of Doppler central frequency has an important effect to accuracy of fixed position in the fixing approach with no reference points for ocean SAR. The effect of Signal-Noise-Ration （SNR） to the estimation of Doppler central frequency has been studied using theoretical method and simulation technique, and results are given in curves. Based on above results, a Doppler measurement mode is adopted in the design of ocean SAR. Compared to common imaging mode, this mode increases SNR of ocean echo by decreasing the bandwidth, then accuracy of fixed position can be improved.
Estimation of Doppler central frequency has an important effect to accuracy of fixed position in the fixing approach with no reference points for ocean SAR. The effect of Signal-Noise-Ration （SNR） to the estimation of Doppler central frequency has been studied using theoretical method and simulation technique, and results are given in curves. Based on above results, a Doppler measurement mode is adopted in the design of ocean SAR. Compared to common imaging mode, this mode increases SNR of ocean echo by decreasing the bandwidth, then accuracy of fixed position can be improved.
2005, 27(8): 1217-1221.
Abstract:
It is a challenge for Space Time Adaptive Processing （STAP） in non-homogeneous environment. Thus, a new maximum likelihood method to moving target detection for phased Airborne Early Warning （AEW） radar is presented in this paper. This new method has advantages of low computational expense, excellent target detection performance in the main clutter field, and strong ability to mitigate isolate interference. Its effectiveness is also verified by the computational results of simulation and the some real data.
It is a challenge for Space Time Adaptive Processing （STAP） in non-homogeneous environment. Thus, a new maximum likelihood method to moving target detection for phased Airborne Early Warning （AEW） radar is presented in this paper. This new method has advantages of low computational expense, excellent target detection performance in the main clutter field, and strong ability to mitigate isolate interference. Its effectiveness is also verified by the computational results of simulation and the some real data.
2005, 27(8): 1222-1225.
Abstract:
This paper, based on the physical model of optically phased array, analyzes the relationship between the number of subarray and the sidelobe level and mainlobe deviation. It gives the realization process of the algorithm based on the combining the sidelobe level and the mainlobe deviation for solving the number of subarray by directly numerical search. And this method is verified to be correct by computer simulation.
This paper, based on the physical model of optically phased array, analyzes the relationship between the number of subarray and the sidelobe level and mainlobe deviation. It gives the realization process of the algorithm based on the combining the sidelobe level and the mainlobe deviation for solving the number of subarray by directly numerical search. And this method is verified to be correct by computer simulation.
The Structure and Implementation of the Two-Frame Corner Turn Memory（CTM）in Real Time Imaging of SAR
2005, 27(8): 1226-1228.
Abstract:
The Corner Turn Memory（CTM） for real time imaging of the Synthetic Aperture Radar（SAR）is presented in this paper. Two types of structure of CTM： the three-frame and the two-frame are discussed, of which the merits and flaws are compared. The representative application of the two-frame CTM is introduced predominantly, of which the implementation in circuit and the result are given with the Double Data Rate Synchronous Dynamic RAM（DDR SDRAM）served as the main memory.
The Corner Turn Memory（CTM） for real time imaging of the Synthetic Aperture Radar（SAR）is presented in this paper. Two types of structure of CTM： the three-frame and the two-frame are discussed, of which the merits and flaws are compared. The representative application of the two-frame CTM is introduced predominantly, of which the implementation in circuit and the result are given with the Double Data Rate Synchronous Dynamic RAM（DDR SDRAM）served as the main memory.
2005, 27(8): 1229-1232.
Abstract:
A new and powerful method for detecting moving targets in a synthetic aperture radar（SAR） image is presented. Phase errors induced by many moving targets are largely quadratic, which provides a basis, by way of a change in the Doppler rate, for estimating the combined effects of azimuth constant velocity and radial acceleration. In this paper, the data in the SAR image is corrected by subtracting the quadratic phase error, and inverse changed by adding the same quadratic phase for comparing, both results are transformed to time domain, where the fixed background clutter have same image intensity. The absolute value of subtracting the two signal expected to have superior moving target detection performance. The experiment result prove this method is valid.
A new and powerful method for detecting moving targets in a synthetic aperture radar（SAR） image is presented. Phase errors induced by many moving targets are largely quadratic, which provides a basis, by way of a change in the Doppler rate, for estimating the combined effects of azimuth constant velocity and radial acceleration. In this paper, the data in the SAR image is corrected by subtracting the quadratic phase error, and inverse changed by adding the same quadratic phase for comparing, both results are transformed to time domain, where the fixed background clutter have same image intensity. The absolute value of subtracting the two signal expected to have superior moving target detection performance. The experiment result prove this method is valid.
2005, 27(8): 1233-1236.
Abstract:
In this paper, the factors that affect the Block Adaptive Vector Quantization （BAVQ） compression performance are analyzed, which are the Signal to compression Noise Ratio （SNR） of Block Adaptive Quantization （BAQ）, the encoding algorithm computation complexity, the statistics and dynamic range of BAQ compressed data. Based on these factors, the paper proposes an improved BAVQ algorithm to compress Synthetic Aperture Radar （SAR） raw data. In the improved algorithm, the traditional block adaptive quantizer is replaced by more bits one. Using this improved BAVQ algorithm to compress high resolution SAR raw data, larger SNR values than the previous compression algorithms under the same compression ratio are obtained. The decompressed images reserve most of details on the images resulted from raw data.
In this paper, the factors that affect the Block Adaptive Vector Quantization （BAVQ） compression performance are analyzed, which are the Signal to compression Noise Ratio （SNR） of Block Adaptive Quantization （BAQ）, the encoding algorithm computation complexity, the statistics and dynamic range of BAQ compressed data. Based on these factors, the paper proposes an improved BAVQ algorithm to compress Synthetic Aperture Radar （SAR） raw data. In the improved algorithm, the traditional block adaptive quantizer is replaced by more bits one. Using this improved BAVQ algorithm to compress high resolution SAR raw data, larger SNR values than the previous compression algorithms under the same compression ratio are obtained. The decompressed images reserve most of details on the images resulted from raw data.
2005, 27(8): 1237-1239.
Abstract:
Firstly, the principle of pseudo-random code modulation based on double-balance modulator is analyzed. On this basis, a new combined modulated fuze-pseudo-random code phase-modulation and sine AM combined modulated fuze is advanced. And the principle of the combined modulated fuze is illustrated and the formula of signals in every aspects is deduced. Finally, by analyzing the performance of the combined modulated fuze, it is proved that the combined modulated fuze has advantageous performance, especially good characteristics of ECCM
Firstly, the principle of pseudo-random code modulation based on double-balance modulator is analyzed. On this basis, a new combined modulated fuze-pseudo-random code phase-modulation and sine AM combined modulated fuze is advanced. And the principle of the combined modulated fuze is illustrated and the formula of signals in every aspects is deduced. Finally, by analyzing the performance of the combined modulated fuze, it is proved that the combined modulated fuze has advantageous performance, especially good characteristics of ECCM
2005, 27(8): 1240-1243.
Abstract:
In waveform storage LFM generator design, quantization precision, clock jitter, D/A converter linear error and output performance distortion cause rise of side label in pulse compression result. The paper analyses these effects and gives quantized results providing valuable reference for engineering design.
In waveform storage LFM generator design, quantization precision, clock jitter, D/A converter linear error and output performance distortion cause rise of side label in pulse compression result. The paper analyses these effects and gives quantized results providing valuable reference for engineering design.
2005, 27(8): 1244-1248.
Abstract:
Multispectral imaging has been widely used in the field of remote sensing. The storage and transmission of large volumes of multispectral data have become significant concerns. Therefore efficient compression is required for storage and transmission. This paper proposes a new multispectral image data compression algorithm （KLT/WT3DSPECK）. First, a 2D wavelet transform is applied to reduce the spatial redundancies. Next a Karhunen-Loeve Transform （KLT） is used to remove the correlation between adjacent spectral bands. Finally a modified 3DSPECK method is proposed and is used to code the transformed coefficients. According to the distribution of energy of the transformed coefficients, a novel 3D octave partitioning scheme and an improved set partitioning zeroblock method are presented. To accelerate the speed and optimize the rate-distortion performance of the embedded bit stream, a fast algorithm of the optimal zeroblock sorting is given. Numerical experiments on two sample multispectral images show that the proposed KLT/WT-3DSPECK algorithm outperforms either the KLT/WT-3DSPIHT algorithm or the 3DWT-based AT-3DSPIHT and 3DSPECK algorithms. Besides having high performance, the KLT/WT-3DSPECK algorithm support progressive transmission.
Multispectral imaging has been widely used in the field of remote sensing. The storage and transmission of large volumes of multispectral data have become significant concerns. Therefore efficient compression is required for storage and transmission. This paper proposes a new multispectral image data compression algorithm （KLT/WT3DSPECK）. First, a 2D wavelet transform is applied to reduce the spatial redundancies. Next a Karhunen-Loeve Transform （KLT） is used to remove the correlation between adjacent spectral bands. Finally a modified 3DSPECK method is proposed and is used to code the transformed coefficients. According to the distribution of energy of the transformed coefficients, a novel 3D octave partitioning scheme and an improved set partitioning zeroblock method are presented. To accelerate the speed and optimize the rate-distortion performance of the embedded bit stream, a fast algorithm of the optimal zeroblock sorting is given. Numerical experiments on two sample multispectral images show that the proposed KLT/WT-3DSPECK algorithm outperforms either the KLT/WT-3DSPIHT algorithm or the 3DWT-based AT-3DSPIHT and 3DSPECK algorithms. Besides having high performance, the KLT/WT-3DSPECK algorithm support progressive transmission.
2005, 27(8): 1249-1253.
Abstract:
More and more attention has been paid to the study of moving object segmentation in MPEG compressed domain these years, which has already developed into a practical technology. In this paper, an algorithm by using motion vectors and DCT coefficients is put forward for segmenting moving object in MPEG compressed domain. As regards local motion scene, the algorithm produces a better result of segmentation than currently adopted ones. Firstly, the motion vectors are processed by accumulation and median filter; then the areas of non-zero motion vectors are rectified by the Bayesian decision to get high-quality segmentation.
More and more attention has been paid to the study of moving object segmentation in MPEG compressed domain these years, which has already developed into a practical technology. In this paper, an algorithm by using motion vectors and DCT coefficients is put forward for segmenting moving object in MPEG compressed domain. As regards local motion scene, the algorithm produces a better result of segmentation than currently adopted ones. Firstly, the motion vectors are processed by accumulation and median filter; then the areas of non-zero motion vectors are rectified by the Bayesian decision to get high-quality segmentation.
2005, 27(8): 1258-1263.
Abstract:
The uplink of a space-time block coded MC-CDMA system equipped with a uniform linear array at the base station of macrocellular is studied. A blind estimation algorithm is proposed to provide the closed-form solutions of both the transmitted symbol sequences and the Directions Of Arrival （DOA） for multiple users without determining the space-time vector channels. An auxiliary matrix including both the coded symbol sequences and DOAs is derived, on which the eigen decomposition is performed to obtain the DOAs of different users. Then, the algorithm exploits the structure of space-time block coding in combination with the finite alphabet property of transmitted symbols to estimate the original symbol sequences for all active users. The computer simulations demonstrate the effectiveness of the proposed scheme.
The uplink of a space-time block coded MC-CDMA system equipped with a uniform linear array at the base station of macrocellular is studied. A blind estimation algorithm is proposed to provide the closed-form solutions of both the transmitted symbol sequences and the Directions Of Arrival （DOA） for multiple users without determining the space-time vector channels. An auxiliary matrix including both the coded symbol sequences and DOAs is derived, on which the eigen decomposition is performed to obtain the DOAs of different users. Then, the algorithm exploits the structure of space-time block coding in combination with the finite alphabet property of transmitted symbols to estimate the original symbol sequences for all active users. The computer simulations demonstrate the effectiveness of the proposed scheme.
2005, 27(8): 1264-1268.
Abstract:
A solution of Ultra-Wide Band（UWB） communication systems based on Cyclic Prefix and Pulse Modulations （UWB-CP/PM） and its corresponding signal processing algorithms are presented for short-range wireless networks in this paper. Borrowing the basic idea from the Single-Carrier system with Cyclic Prefix （SC-CP）, an UWB-CP/PM system is capable of elegantly combating multipath interferences by employing transform-domain equalization. Due to pulse modulations, it can significantly simplify its transceiver. By exploiting the property that the pulse repetition period is much larger than the duration of each pulse, it is able to not only ease the requirements on the speed of baseband processing through multi-branch receiving and parallel processing, but also efficiently suppress fading, narrow-band interferences and multiuser interferences by transform-domain signal processing. Simulation results verify the above-mentioned claims.
A solution of Ultra-Wide Band（UWB） communication systems based on Cyclic Prefix and Pulse Modulations （UWB-CP/PM） and its corresponding signal processing algorithms are presented for short-range wireless networks in this paper. Borrowing the basic idea from the Single-Carrier system with Cyclic Prefix （SC-CP）, an UWB-CP/PM system is capable of elegantly combating multipath interferences by employing transform-domain equalization. Due to pulse modulations, it can significantly simplify its transceiver. By exploiting the property that the pulse repetition period is much larger than the duration of each pulse, it is able to not only ease the requirements on the speed of baseband processing through multi-branch receiving and parallel processing, but also efficiently suppress fading, narrow-band interferences and multiuser interferences by transform-domain signal processing. Simulation results verify the above-mentioned claims.
2005, 27(8): 1269-1273.
Abstract:
This paper gives a serial acquisition method which can be easily implemented in time hopping ultra-wide band system. Based on this method, the acquisition performance in the multiuser environment is analyzed, and the relationships between the detection probability, false alarm probability, detection threshold and average acquisition time are given. From the theoretical analysis and numerical simulation, it is noted that with the increasing of user number, the detection probability will decrease. By contrary, the false alarm and the detection threshold will increase accordingly, and the acquisition time will also increase from s to ms.
This paper gives a serial acquisition method which can be easily implemented in time hopping ultra-wide band system. Based on this method, the acquisition performance in the multiuser environment is analyzed, and the relationships between the detection probability, false alarm probability, detection threshold and average acquisition time are given. From the theoretical analysis and numerical simulation, it is noted that with the increasing of user number, the detection probability will decrease. By contrary, the false alarm and the detection threshold will increase accordingly, and the acquisition time will also increase from s to ms.
2005, 27(8): 1274-1277.
Abstract:
A novel differential detection method, called Frequency Domain Spread Spectrum Chip-Level Differential Detection （FD-SS-CLDD） is proposed in frequency domain spread spectrum system. The Moment Generating Function （MGF） of decision variable and a saddle point approximation method are exploited to analyze the BER performance of FD-SS-CLDD, and the theoretical results are evaluated by simulation. If the coherent bandwidth of channel does not exceed the occupied bandwidth of two chips, with the increase of delay spread of the channel, FD-SS-CLDD exhibits a better performance to make the system resistant to frequency-selective fading.
A novel differential detection method, called Frequency Domain Spread Spectrum Chip-Level Differential Detection （FD-SS-CLDD） is proposed in frequency domain spread spectrum system. The Moment Generating Function （MGF） of decision variable and a saddle point approximation method are exploited to analyze the BER performance of FD-SS-CLDD, and the theoretical results are evaluated by simulation. If the coherent bandwidth of channel does not exceed the occupied bandwidth of two chips, with the increase of delay spread of the channel, FD-SS-CLDD exhibits a better performance to make the system resistant to frequency-selective fading.
2005, 27(8): 1278-1281.
Abstract:
In this paper adaptive modulation in Frequency Division Duplexing(FDD)communications over a fading channel is studied and packet structure and structure of adaptive modulation are proposed. Further, influence of multiplication of Doppler frequency and packet length is analyzed. Iterative modulation scheme is proposed which adjusts modulation scheme according to different multiplication. Simulation results show that in different multiplication region, different mode can get maximum spectrum efficiency and spectrum efficiency decreases with the increase of multiplication.
In this paper adaptive modulation in Frequency Division Duplexing(FDD)communications over a fading channel is studied and packet structure and structure of adaptive modulation are proposed. Further, influence of multiplication of Doppler frequency and packet length is analyzed. Iterative modulation scheme is proposed which adjusts modulation scheme according to different multiplication. Simulation results show that in different multiplication region, different mode can get maximum spectrum efficiency and spectrum efficiency decreases with the increase of multiplication.
2005, 27(8): 1282-1286.
Abstract:
In this paper the error-correcting performance of frequency transition function for Differential Frequency Hopping （DFH） communication system is analyzed first. Then a Viterbi algorithm is proposed and applied to frequency sequence decoding of DFH receiver, and it is further improved by the full use of the characteristics of transition function. The decoding performance of Viterbi algorithm is analyzed with the requirement that the transition function should achieve the best error-correcting performance. Simulation results show that 5- 8dB gain could be achieved for stochastic frequency detection error when SNR is low.
In this paper the error-correcting performance of frequency transition function for Differential Frequency Hopping （DFH） communication system is analyzed first. Then a Viterbi algorithm is proposed and applied to frequency sequence decoding of DFH receiver, and it is further improved by the full use of the characteristics of transition function. The decoding performance of Viterbi algorithm is analyzed with the requirement that the transition function should achieve the best error-correcting performance. Simulation results show that 5- 8dB gain could be achieved for stochastic frequency detection error when SNR is low.
2005, 27(8): 1290-1294.
Abstract:
A concept of weighted reliability index normalized by the total capacity called index of macroscopic reliability is introduced in this paper to evaluate reliability of broadband network comprehensively and objectively. This index combines communication capacity with link reliability parameter effectively. The key technique to achieve complete algebraic calculation of this index is finding out an algebraic algorithm which can calculate all routes among network nodes. This paper proposes a new algebraic calculation routing algorithm, by which n times transformation operations can get all routes between two nodes for network with n nodes. The complete algebraic calculation of network reliability index is researched base on this new routing algorithm, it is easy to program and convenient to calculate reliability index of telecommunication network with computer. This method overcomes the difficulties in calculating normalized reliability index weighted by total capacity and can be used in practice. The calculation procedure of the algorithm is shown through examples in details and its correctness is validated.
A concept of weighted reliability index normalized by the total capacity called index of macroscopic reliability is introduced in this paper to evaluate reliability of broadband network comprehensively and objectively. This index combines communication capacity with link reliability parameter effectively. The key technique to achieve complete algebraic calculation of this index is finding out an algebraic algorithm which can calculate all routes among network nodes. This paper proposes a new algebraic calculation routing algorithm, by which n times transformation operations can get all routes between two nodes for network with n nodes. The complete algebraic calculation of network reliability index is researched base on this new routing algorithm, it is easy to program and convenient to calculate reliability index of telecommunication network with computer. This method overcomes the difficulties in calculating normalized reliability index weighted by total capacity and can be used in practice. The calculation procedure of the algorithm is shown through examples in details and its correctness is validated.
2005, 27(8): 1295-1298.
Abstract:
Fiber links, because of sharing some common physical resources （such as fiber cable, conduit, right of way, etc.）, have certain failure-dependent. The term Shared Risk Link Groups （SRLG） is introduced to describe the relationship between links with shared risk; SRLG diversity has become the important constraint of protection design problem. This paper addresses SRLG-constraint-based shared-path protection design problem with differentiated reliability. Via SRLG conditional failure probability concept, an efficient PSD-SPP （Partial SRLG-Disjoint Shared-Path Protection） algorithm is proposed to solve the protection design problem with differentiated reliability when considering links failure-dependence. Simulation result shows this algorithm not only efficiently satisfies the user-specific requirement, but also effectively decreases the network-blocking ratio.
Fiber links, because of sharing some common physical resources （such as fiber cable, conduit, right of way, etc.）, have certain failure-dependent. The term Shared Risk Link Groups （SRLG） is introduced to describe the relationship between links with shared risk; SRLG diversity has become the important constraint of protection design problem. This paper addresses SRLG-constraint-based shared-path protection design problem with differentiated reliability. Via SRLG conditional failure probability concept, an efficient PSD-SPP （Partial SRLG-Disjoint Shared-Path Protection） algorithm is proposed to solve the protection design problem with differentiated reliability when considering links failure-dependence. Simulation result shows this algorithm not only efficiently satisfies the user-specific requirement, but also effectively decreases the network-blocking ratio.
2005, 27(8): 1299-1303.
Abstract:
Considering both the survivability and traffic grooming, a differentiated shared protection algorithm using wavelength layered-graph called PSPTG, which means Partial Shared-path Protection algorithm supporting Traffic Grooming, is proposed. In this algorithm, a shared protection scheme of partial lightpath based on link reliability is presented to meet the requests of reliability and bandwidth of connections. Simulation results show that the algorithm is efficient in terms of resources utilization.
Considering both the survivability and traffic grooming, a differentiated shared protection algorithm using wavelength layered-graph called PSPTG, which means Partial Shared-path Protection algorithm supporting Traffic Grooming, is proposed. In this algorithm, a shared protection scheme of partial lightpath based on link reliability is presented to meet the requests of reliability and bandwidth of connections. Simulation results show that the algorithm is efficient in terms of resources utilization.
2005, 27(8): 1304-1309.
Abstract:
This paper presents a method of information hiding based on the digital-position information, bringing forward an augmented identity matrix and a definite arithmetic upon it. In this method, if the single digital-position information is used, embedding efficiency can achieve m when n = 2m -1. And if the multi-digital-position information is used, data embedding rate can almost reach 1 when n is big enough, with the condition of an unchanged embedding efficiency. So more information can be hided in the host information with same bits and it can be used in stream multimedia, hidings with great information, etc. The proposed method with low computing complexity can be realized easily. Satisfying experimental results are gained on PC and LAN
This paper presents a method of information hiding based on the digital-position information, bringing forward an augmented identity matrix and a definite arithmetic upon it. In this method, if the single digital-position information is used, embedding efficiency can achieve m when n = 2m -1. And if the multi-digital-position information is used, data embedding rate can almost reach 1 when n is big enough, with the condition of an unchanged embedding efficiency. So more information can be hided in the host information with same bits and it can be used in stream multimedia, hidings with great information, etc. The proposed method with low computing complexity can be realized easily. Satisfying experimental results are gained on PC and LAN
2005, 27(8): 1310-1314.
Abstract:
As emergence of several access methods, many LANs use access of dynamic IP address. Virtual Private Network（VPN）of static configuration is not applicable. Thus, how to exchange information, construct VPN in dynamic network is indicated as new question for research. A secure and dynamic tunneling mechanism is presented. And message of this mechanism is defined. This mechanism can solve above mentioned issue. Authentication and anti-replay function are introduced to avoid secure problems. The result of experiment shows that this mechanism can construct VPN securely and efficiently in dynamic network.
As emergence of several access methods, many LANs use access of dynamic IP address. Virtual Private Network（VPN）of static configuration is not applicable. Thus, how to exchange information, construct VPN in dynamic network is indicated as new question for research. A secure and dynamic tunneling mechanism is presented. And message of this mechanism is defined. This mechanism can solve above mentioned issue. Authentication and anti-replay function are introduced to avoid secure problems. The result of experiment shows that this mechanism can construct VPN securely and efficiently in dynamic network.
2005, 27(8): 1315-1319.
Abstract:
A Priority BackoffAIgorithm （PBA） for IEEE 802.11 DCF is presented in this paper. The basic idea of PBA is each station should collect statistical data of other stations＇ transmission while sensing the channel, and maintaining a sent data table for all stations in network. When the station has data to transmit, it will calculate contention window based on the statistical data in sent data table and its own priority. Computer simulationproves that PBA can properly assign network capacity among stations in proportion to their priorities as well as enhance the network saturation throughput.
A Priority BackoffAIgorithm （PBA） for IEEE 802.11 DCF is presented in this paper. The basic idea of PBA is each station should collect statistical data of other stations＇ transmission while sensing the channel, and maintaining a sent data table for all stations in network. When the station has data to transmit, it will calculate contention window based on the statistical data in sent data table and its own priority. Computer simulationproves that PBA can properly assign network capacity among stations in proportion to their priorities as well as enhance the network saturation throughput.
2005, 27(8): 1320-1323.
Abstract:
This paper firstly presents a novel estimation technology EWMA （double Exponential Weighted Moving Average）, which employs two EWMA filters to measure data, overcomes the defect that traditional EWMA estimation technology does not achieve fine agility and stability, and provides much more accurate , flexible data estimation. Secondly, the effectiveness of dEWMA is validated by applying to RED gateway. The simulations show that the performance of RED with dEWMA is better than that of RED with non-dEWMA.
This paper firstly presents a novel estimation technology EWMA （double Exponential Weighted Moving Average）, which employs two EWMA filters to measure data, overcomes the defect that traditional EWMA estimation technology does not achieve fine agility and stability, and provides much more accurate , flexible data estimation. Secondly, the effectiveness of dEWMA is validated by applying to RED gateway. The simulations show that the performance of RED with dEWMA is better than that of RED with non-dEWMA.
2005, 27(8): 1324-1327.
Abstract:
A Traffic Engineering Algorithm Supporting QoS in MPLS Networks
A Traffic Engineering Algorithm Supporting QoS in MPLS Networks
2005, 27(8): 1335-1337.
Abstract:
In this paper, the construction of complementary sequence pairs are studied, and a new constructional method is found, with which it can get a complementary sequence pairs of length MN by a complementary sequence pairs of length M and a complementary sequence pairs of length N. This is an expansion of the former constructional method which can only get complementary sequence pairs of even length and is usefull to study the property of odd length complementary sequence pairs.
In this paper, the construction of complementary sequence pairs are studied, and a new constructional method is found, with which it can get a complementary sequence pairs of length MN by a complementary sequence pairs of length M and a complementary sequence pairs of length N. This is an expansion of the former constructional method which can only get complementary sequence pairs of even length and is usefull to study the property of odd length complementary sequence pairs.
2005, 27(8): 1338-1341.
Abstract:
A noncoherent Reduced State Differential Sequence Detection （RSDSD） for Continuous Phase Modulation （CPM） is proposed in this paper, The algorithm makes use of the reduced state trellis based on Reduced State Sequence Detection （RSSD） and performs one-symbol differential Viterbi detection. The minimum square Euclidean distance of the reduced state trellis is analyzed for full response CPM and partial response CPM. Performance of RSSD and RSDSD is simulated for octal 2RC signal with h=1/8 in the AWGN channel and comparisons are made between different reduction schemes and between coherent RSSD and noncoherent RSDSD with Doppler frequency shifts. Simulation results show： although the proposed algorithm is degraded by 2dB at 10-3 bit error rate compared with coherent Maximum Likelihood Sequence Detection（MLSD）, it is more appropriate and robust to the situation when the carrier recovery is difficult.
A noncoherent Reduced State Differential Sequence Detection （RSDSD） for Continuous Phase Modulation （CPM） is proposed in this paper, The algorithm makes use of the reduced state trellis based on Reduced State Sequence Detection （RSSD） and performs one-symbol differential Viterbi detection. The minimum square Euclidean distance of the reduced state trellis is analyzed for full response CPM and partial response CPM. Performance of RSSD and RSDSD is simulated for octal 2RC signal with h=1/8 in the AWGN channel and comparisons are made between different reduction schemes and between coherent RSSD and noncoherent RSDSD with Doppler frequency shifts. Simulation results show： although the proposed algorithm is degraded by 2dB at 10-3 bit error rate compared with coherent Maximum Likelihood Sequence Detection（MLSD）, it is more appropriate and robust to the situation when the carrier recovery is difficult.
2005, 27(8): 1342-1344.
Abstract:
The longitudinal slot array of rectangular waveguide's wider side is analyzed and designed according to the equivalent magnetic current. The parameters of the array are obtained with the method of quasi-Newton, and the inner and external coupling coefficients are calculated and taken into account. Because the admittance of single slot is calculate with MOM, and the thickness of waveguide's wall is considered, the convergent rate is enhanced. As an example, an S-waveband slot array of 24 elements is designed, and the measured and simulated results are agreed well with each other.
The longitudinal slot array of rectangular waveguide's wider side is analyzed and designed according to the equivalent magnetic current. The parameters of the array are obtained with the method of quasi-Newton, and the inner and external coupling coefficients are calculated and taken into account. Because the admittance of single slot is calculate with MOM, and the thickness of waveguide's wall is considered, the convergent rate is enhanced. As an example, an S-waveband slot array of 24 elements is designed, and the measured and simulated results are agreed well with each other.
2005, 27(8): 1254-1257.
Abstract:
A novel DWPM （Discrete Wavelet Packet Modulation） system with blind channel identification based on Maximum Likelihood （ML） algorithm is studied for multipath fading channel. The Channel State Information （CSI） is obtained with blind channel identification method and inter-symbol interference is suppressed by H matrix based on ZF （Zero Forcing） algorithm. Finally, the demodulated symbols are detected by ML algorithm. The performance of the system under the multipath fading channel is analyzed by simulation, The simulation results show the performance of the system is better than that of the traditional OFDM system.
A novel DWPM （Discrete Wavelet Packet Modulation） system with blind channel identification based on Maximum Likelihood （ML） algorithm is studied for multipath fading channel. The Channel State Information （CSI） is obtained with blind channel identification method and inter-symbol interference is suppressed by H matrix based on ZF （Zero Forcing） algorithm. Finally, the demodulated symbols are detected by ML algorithm. The performance of the system under the multipath fading channel is analyzed by simulation, The simulation results show the performance of the system is better than that of the traditional OFDM system.
2005, 27(8): 1287-1289.
Abstract:
A new kind of algorithm is proposed which can produce random error vector without looking up the syndrome-error table. An error vector with larger Hamming weight can be produced by mixing a part of the original error vector with the plaintext. A modified Rao-Nam scheme based on the new algorithm is presented, which requires no storage for random error vector. The scheme is efficient and practical, and offers a much higher security level.
A new kind of algorithm is proposed which can produce random error vector without looking up the syndrome-error table. An error vector with larger Hamming weight can be produced by mixing a part of the original error vector with the plaintext. A modified Rao-Nam scheme based on the new algorithm is presented, which requires no storage for random error vector. The scheme is efficient and practical, and offers a much higher security level.
2005, 27(8): 1328-1334.
Abstract:
Radar High Range Resolution Profiles （HRRP） provide potentially discriminative information on the geometry of target, which has been shown to be promising signatures for radar Automatic Target Recognition （ATR） application. In this paper, we review the present research status and some key techniques in this field, including the property of HRRP, preprocessing methods, feature extraction and classifier design. Several future research directions in this field are discussed at the end of this paper.
Radar High Range Resolution Profiles （HRRP） provide potentially discriminative information on the geometry of target, which has been shown to be promising signatures for radar Automatic Target Recognition （ATR） application. In this paper, we review the present research status and some key techniques in this field, including the property of HRRP, preprocessing methods, feature extraction and classifier design. Several future research directions in this field are discussed at the end of this paper.
