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2005 Vol. 27, No. 7
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2005, 27(7): 1009-1012.
Abstract:
In this paper, a remote sensing image matching algorithm based on distance transformation and genetic algorithms is proposed. Firstly, the reference images and target images are processed using histogram equalization to overcome different brightness of them. Secondly, distance transformation is implemented on the images after histogram equalization. Lastly, genetic algorithms are used to match the distance images. The experimental results confirm the proposed algorithm can improve the efficiency greatly while guarantee the accuracy.
In this paper, a remote sensing image matching algorithm based on distance transformation and genetic algorithms is proposed. Firstly, the reference images and target images are processed using histogram equalization to overcome different brightness of them. Secondly, distance transformation is implemented on the images after histogram equalization. Lastly, genetic algorithms are used to match the distance images. The experimental results confirm the proposed algorithm can improve the efficiency greatly while guarantee the accuracy.
2005, 27(7): 1013-1016.
Abstract:
Feature points in images are commonly used for image registration. Feature points can be classified as in narrow sense and in broad sense. Feature Points in Broad Sense (FPBS) can be defined in different ways. A new definition of FPBS is proposed that is reasonable for image registration. The FPBS can be detected automatically by the use of multi-scale wavelet transform and a few additional restrictions that control the complexity and nonperiodicity of local regions. After feature point sets are extracted separately from the two images under consideration, the relation between them is then established by a two-stage matching algorithm. The registration transform is found by minimizing the Root Mean Square Error (RMSE) of the control points. An iterative optimization mechanism is used to refine the registration. Several experimental results of image registration can illustrate the performance of the method.
Feature points in images are commonly used for image registration. Feature points can be classified as in narrow sense and in broad sense. Feature Points in Broad Sense (FPBS) can be defined in different ways. A new definition of FPBS is proposed that is reasonable for image registration. The FPBS can be detected automatically by the use of multi-scale wavelet transform and a few additional restrictions that control the complexity and nonperiodicity of local regions. After feature point sets are extracted separately from the two images under consideration, the relation between them is then established by a two-stage matching algorithm. The registration transform is found by minimizing the Root Mean Square Error (RMSE) of the control points. An iterative optimization mechanism is used to refine the registration. Several experimental results of image registration can illustrate the performance of the method.
2005, 27(7): 1017-1020.
Abstract:
The Haar and CDF(2,2) wavelet transforms can be implemented by the lifting scheme. They are combined with Haar-without-update wavelet and then an adaptive wavelet transform is constructed. It can adaptively match the wavelet to a given signal. The simulation results show that the adaptive wavelet transform has advantages of both Haar and CDF(2,2) wavelets and performs well for the smooth and edge-dominated regions. Therefore it should have wider applications.
The Haar and CDF(2,2) wavelet transforms can be implemented by the lifting scheme. They are combined with Haar-without-update wavelet and then an adaptive wavelet transform is constructed. It can adaptively match the wavelet to a given signal. The simulation results show that the adaptive wavelet transform has advantages of both Haar and CDF(2,2) wavelets and performs well for the smooth and edge-dominated regions. Therefore it should have wider applications.
2005, 27(7): 1021-1024.
Abstract:
A two-step approach for tracking moving object is proposed in this paper. According of this approach, the structure template of object is firstly extracted with morphologic methods, and then the object tracking is performed with the structure template. The structure template is composed with the stable edges and the cross-points, which can describe the essential structure information of objects. The tracking processing can be divided into two steps: in the first step, the structure template is wholly moved very closed to the tracked object, and in the second step, the structure template is modified to converge to the cross-points and the edges in object image. Because of considering the structure information of object, the robusticity of tracking can be improved greatly.
A two-step approach for tracking moving object is proposed in this paper. According of this approach, the structure template of object is firstly extracted with morphologic methods, and then the object tracking is performed with the structure template. The structure template is composed with the stable edges and the cross-points, which can describe the essential structure information of objects. The tracking processing can be divided into two steps: in the first step, the structure template is wholly moved very closed to the tracked object, and in the second step, the structure template is modified to converge to the cross-points and the edges in object image. Because of considering the structure information of object, the robusticity of tracking can be improved greatly.
2005, 27(7): 1025-1029.
Abstract:
In this paper, the methodology of likelihood score normalization is studied. The text-independent speaker recognition system based on the adapted Gaussion Mixture Models(GMMs) is established, and the approach to normalize scores combining speaker-independent background model and the speaker-dependent models of cohort speaker sets are proposed. The speaker verification experiments over telephone channels show that based on the likelihood ratio of adapted GMMs system, both cohort normalization and hybrid score normalization approaches can improve the verification performance of baseline system using Universal Background Model (UBM). Specially, the hybrid approach combining UBM and cohort models selected during testing (T-cohort normalization) achieve the best performance. At a miss probability of 5%, the hybrid approach using UBM and T-cohort models reduce the false alarm rate to 0.5% compared to 2% for the baseline.
In this paper, the methodology of likelihood score normalization is studied. The text-independent speaker recognition system based on the adapted Gaussion Mixture Models(GMMs) is established, and the approach to normalize scores combining speaker-independent background model and the speaker-dependent models of cohort speaker sets are proposed. The speaker verification experiments over telephone channels show that based on the likelihood ratio of adapted GMMs system, both cohort normalization and hybrid score normalization approaches can improve the verification performance of baseline system using Universal Background Model (UBM). Specially, the hybrid approach combining UBM and cohort models selected during testing (T-cohort normalization) achieve the best performance. At a miss probability of 5%, the hybrid approach using UBM and T-cohort models reduce the false alarm rate to 0.5% compared to 2% for the baseline.
2005, 27(7): 1030-1034.
Abstract:
A novel wavelet image coder based on morphological dilation and run-length coding, dilation-run algorithm, is proposed according to both intra-subband clustering of significant wavelet coefficients and inter-subband dependency in significant fields. The algorithm mainly involves discrete wavelet transform, bit-plane coding, morphological dilation of significant coefficient cluster within subbands, coefficients significance predicting across subbands, run-length coding of the insignificant coefficients before each seed and adaptive arithmetic coding. The two key features of the algorithm are morphological dilation and run-length coding. The morphological dilation operator is used to search and encode the significant coefficients in each cluster, while a new run-length coding method is used to encode the position of the seed of each cluster, which is the start pixel of the dilation. The dilation-run algorithm, as a kind of embedded coder, is also rate scalable. The experimental results show that the new coder outperforms the zerotree coder SP1HT and is competitive with the morphology coder MRWD and SLCCA. For images with strong clustering feature after the wavelet transform, the new coder outperforms both the morphology coders above.
A novel wavelet image coder based on morphological dilation and run-length coding, dilation-run algorithm, is proposed according to both intra-subband clustering of significant wavelet coefficients and inter-subband dependency in significant fields. The algorithm mainly involves discrete wavelet transform, bit-plane coding, morphological dilation of significant coefficient cluster within subbands, coefficients significance predicting across subbands, run-length coding of the insignificant coefficients before each seed and adaptive arithmetic coding. The two key features of the algorithm are morphological dilation and run-length coding. The morphological dilation operator is used to search and encode the significant coefficients in each cluster, while a new run-length coding method is used to encode the position of the seed of each cluster, which is the start pixel of the dilation. The dilation-run algorithm, as a kind of embedded coder, is also rate scalable. The experimental results show that the new coder outperforms the zerotree coder SP1HT and is competitive with the morphology coder MRWD and SLCCA. For images with strong clustering feature after the wavelet transform, the new coder outperforms both the morphology coders above.
2005, 27(7): 1035-1038.
Abstract:
A digital watermarking scheme is proposed in this paper, which is based on Independent Component Analysis (ICA) and able to resist copy attack effectively. In this algorithm, both the image signature describing the original image uniquely and the watermark are embedded into the original image synchronously and extracted through ICA techniques. By comparing the re-calculated signature of the marked image according to the image signature algorithm with the extracted one, the legality of the marked image can be determined and the purpose of resistance to copy attack can also be realized. Simulation results demonstrate the robustness and validity of this proposed method.
A digital watermarking scheme is proposed in this paper, which is based on Independent Component Analysis (ICA) and able to resist copy attack effectively. In this algorithm, both the image signature describing the original image uniquely and the watermark are embedded into the original image synchronously and extracted through ICA techniques. By comparing the re-calculated signature of the marked image according to the image signature algorithm with the extracted one, the legality of the marked image can be determined and the purpose of resistance to copy attack can also be realized. Simulation results demonstrate the robustness and validity of this proposed method.
2005, 27(7): 1039-1042.
Abstract:
A blind wavelet-based watermarking algorithm with robust for image cropping is proposed. The original image is transformed using wavelet transform and the watermarks are embedded in two selected subbands according to neighboring symbols mean value and odd-even adjugement rule. This is a blind watermarking algorithm which can confirm the copyright without original image. Experimental results and attack analysis show that the watermark algorithm proposed in this paper is transparent and robust to various attacks. In particular, the robustness of wavelet domain watermarking to cropping attack and incorporating attacks is increased.
A blind wavelet-based watermarking algorithm with robust for image cropping is proposed. The original image is transformed using wavelet transform and the watermarks are embedded in two selected subbands according to neighboring symbols mean value and odd-even adjugement rule. This is a blind watermarking algorithm which can confirm the copyright without original image. Experimental results and attack analysis show that the watermark algorithm proposed in this paper is transparent and robust to various attacks. In particular, the robustness of wavelet domain watermarking to cropping attack and incorporating attacks is increased.
2005, 27(7): 1043-1046.
Abstract:
The incompleteness of the frame of discernment is one of the main difficulties confronted in the application of the evidence theory. In this paper, through introducing a newly defined evidence frame which divides the frame of discernment into known and unknown parts, an open frame method to represent and combine evidence under incomplete frame is proposed. This method can distinguish the incompleteness of frame from the conflict of evidence clearly. It also presents a rational way to assign a BPA to the set of unknown propositions. Therefore such a method avoids the problems confronted by the D-S theory and Smetss open world assumption in dealing with incomplete frame.
The incompleteness of the frame of discernment is one of the main difficulties confronted in the application of the evidence theory. In this paper, through introducing a newly defined evidence frame which divides the frame of discernment into known and unknown parts, an open frame method to represent and combine evidence under incomplete frame is proposed. This method can distinguish the incompleteness of frame from the conflict of evidence clearly. It also presents a rational way to assign a BPA to the set of unknown propositions. Therefore such a method avoids the problems confronted by the D-S theory and Smetss open world assumption in dealing with incomplete frame.
Automatic Classification of Chinese Documents Based on Rough Set and Improved Quick-Reduce Algorithm
2005, 27(7): 1047-1052.
Abstract:
Much of the previous automatic Text Classification (TC) methods are closely connected with the construction of document vectors. With each term corresponding to a unit in the vector, this method maps the document vectors into a very high dimensional space, possibly of tens of thousands of dimension, which results in a massive amount of calculation. Since the traditional algorithms based on frequency and threshold filtering may often lead to the loss of effective information, this paper presents a new system for TC, which introduces rough set theory that can greatly reduce the document vector dimensions by reduction algorithm. The empirical results prove to be very successful, for it can not only effectively reduce the dimensional space, but also reach higher accuracy while losing less information compared with usual reduction methods.
Much of the previous automatic Text Classification (TC) methods are closely connected with the construction of document vectors. With each term corresponding to a unit in the vector, this method maps the document vectors into a very high dimensional space, possibly of tens of thousands of dimension, which results in a massive amount of calculation. Since the traditional algorithms based on frequency and threshold filtering may often lead to the loss of effective information, this paper presents a new system for TC, which introduces rough set theory that can greatly reduce the document vector dimensions by reduction algorithm. The empirical results prove to be very successful, for it can not only effectively reduce the dimensional space, but also reach higher accuracy while losing less information compared with usual reduction methods.
2005, 27(7): 1053-1057.
Abstract:
H.264/AVC is the newest video coding standard with high compression efficiency. Because it will take a long time to code with extremely complex algorithm, it can not achieve real-time application. In this paper, according to the characteristic of intra-frame prediction algorithm, a fast algorithm based on 2D-histogram is proposed. This algorithm will predict every macroblock before coding, then selecting one of the two prediction modes. Therefore, the complexity of algorithm and coding time are reduced dramatically. Experimental results show that the coding speed of proposed algorithm is 16.26% faster than that of H.264/AVC, with a little bit increase, and the PSNR is invariable.
H.264/AVC is the newest video coding standard with high compression efficiency. Because it will take a long time to code with extremely complex algorithm, it can not achieve real-time application. In this paper, according to the characteristic of intra-frame prediction algorithm, a fast algorithm based on 2D-histogram is proposed. This algorithm will predict every macroblock before coding, then selecting one of the two prediction modes. Therefore, the complexity of algorithm and coding time are reduced dramatically. Experimental results show that the coding speed of proposed algorithm is 16.26% faster than that of H.264/AVC, with a little bit increase, and the PSNR is invariable.
2005, 27(7): 1058-1060.
Abstract:
A new Single-Input-Multiple-Output (SIMO) model by oversampling the output of an IIR channel is proposed. This new model is much simpler than existing one and it makes blind IIR channel identification easier to be achieved. Extensive discussions and computer simulation results are given. The efficiency and effectiveness of oversampling ratio and subchannels number of the proposed model are presented. This becomes an important cornerstone for further study in blind IIR channel identification.
A new Single-Input-Multiple-Output (SIMO) model by oversampling the output of an IIR channel is proposed. This new model is much simpler than existing one and it makes blind IIR channel identification easier to be achieved. Extensive discussions and computer simulation results are given. The efficiency and effectiveness of oversampling ratio and subchannels number of the proposed model are presented. This becomes an important cornerstone for further study in blind IIR channel identification.
2005, 27(7): 1061-1064.
Abstract:
This paper proves that Ordered Statistic with Greatest Option CFAR(OSGO-CFAR) and Ordered Statistic with Smallest Option CFAR(OSSO-CFAR) are also of CFAR under homeomorphic independent K-distributed clutter background when the shape parameter is known. The performance of two detectors is analyzed against uniform clutter background, clutter edges and multiple target environments. Compared to OS-CFAR, OSGO-CFAR has little additional detectability loss against uniform clutter background and multiple target environments, and it has improved control ability of false alarm against clutter edges. Therefore, OSGO-CFAR detector is a kind of CFAR detector which has better performance during K-distributed clutter.
This paper proves that Ordered Statistic with Greatest Option CFAR(OSGO-CFAR) and Ordered Statistic with Smallest Option CFAR(OSSO-CFAR) are also of CFAR under homeomorphic independent K-distributed clutter background when the shape parameter is known. The performance of two detectors is analyzed against uniform clutter background, clutter edges and multiple target environments. Compared to OS-CFAR, OSGO-CFAR has little additional detectability loss against uniform clutter background and multiple target environments, and it has improved control ability of false alarm against clutter edges. Therefore, OSGO-CFAR detector is a kind of CFAR detector which has better performance during K-distributed clutter.
2005, 27(7): 1065-1068.
Abstract:
This paper proposed a new automatic target detection and orientation method based on image entropy variation and window energy detection. This method decides whether target is existing by the variation of entropy in ground penetrating radar image before synthetic aperture processing and after synthetic aperture processing, then decides the location of target by detecting window energy in ground penetrating radar synthetic aperture image. The results of processing measurement data show this method is effective.
This paper proposed a new automatic target detection and orientation method based on image entropy variation and window energy detection. This method decides whether target is existing by the variation of entropy in ground penetrating radar image before synthetic aperture processing and after synthetic aperture processing, then decides the location of target by detecting window energy in ground penetrating radar synthetic aperture image. The results of processing measurement data show this method is effective.
2005, 27(7): 1069-1072.
Abstract:
A simple polarimetric CFAR detector for coherent radar against a Gaussian background is presented. The expression of PFA for the detector is derived. It is shown that the proposed detector has the constant false alarm properties with respect to the covariance matrix of the clutter. With respect to the polarimetric generalized likelihood ratio test detector, the proposed one has less complexity. It is appropriate to high SCR and unknown steering, vector case. The performance in different polarimetric cases is analyzed.
A simple polarimetric CFAR detector for coherent radar against a Gaussian background is presented. The expression of PFA for the detector is derived. It is shown that the proposed detector has the constant false alarm properties with respect to the covariance matrix of the clutter. With respect to the polarimetric generalized likelihood ratio test detector, the proposed one has less complexity. It is appropriate to high SCR and unknown steering, vector case. The performance in different polarimetric cases is analyzed.
2005, 27(7): 1073-1076.
Abstract:
Single Phase Center Multiple Beams(SPCMB) technique is one of solutions to implement high resolution wide swath spaceborne synthetic aperture radar systems. The system model and signal characteristics are described based on the introduction to the principle of single phase center multiple beams technique in the paper. A method of azimuth signal processing is presented, and is proved by spaceborne point-target simulation and airborne raw data simulation.
Single Phase Center Multiple Beams(SPCMB) technique is one of solutions to implement high resolution wide swath spaceborne synthetic aperture radar systems. The system model and signal characteristics are described based on the introduction to the principle of single phase center multiple beams technique in the paper. A method of azimuth signal processing is presented, and is proved by spaceborne point-target simulation and airborne raw data simulation.
2005, 27(7): 1077-1080.
Abstract:
Considering the spread spectrum orientation systems using difference carrier phase to measure distance, this paper proposed a method for acquiring difference carrier phase by using pilot symbol. Using the spread-spectrum codes, signals from different transmitters can be distinguished, and the interstation interference is depressed. In the paper, the mathematical model for the proposed method is deduced, and the mean and variance of the acquired carrier difference phase of the proposed method are analyzed and simulated. The results show that the method is valid.
Considering the spread spectrum orientation systems using difference carrier phase to measure distance, this paper proposed a method for acquiring difference carrier phase by using pilot symbol. Using the spread-spectrum codes, signals from different transmitters can be distinguished, and the interstation interference is depressed. In the paper, the mathematical model for the proposed method is deduced, and the mean and variance of the acquired carrier difference phase of the proposed method are analyzed and simulated. The results show that the method is valid.
2005, 27(7): 1081-1086.
Abstract:
The spectral correlation function of PN code-carrier FM is studied, especially for PRBC, SFM-PRBC and LFM-PRBC. Based on the relation between SCF and AF, and LPTV theory of stationary stochastic process, in detail, the SCF of the above three compound signals is derived respectively, whose characterization is also exploited. By the characteristic analyse of SCF of/-section and a -section, it shows that the SCF includes the information of carrier FM and PN code while the WGN is well suppressed, and all of those establish theoretic foundation for the signal recognition and parameter estimation of PN code-carrier FM based on the SC method.
The spectral correlation function of PN code-carrier FM is studied, especially for PRBC, SFM-PRBC and LFM-PRBC. Based on the relation between SCF and AF, and LPTV theory of stationary stochastic process, in detail, the SCF of the above three compound signals is derived respectively, whose characterization is also exploited. By the characteristic analyse of SCF of/-section and a -section, it shows that the SCF includes the information of carrier FM and PN code while the WGN is well suppressed, and all of those establish theoretic foundation for the signal recognition and parameter estimation of PN code-carrier FM based on the SC method.
2005, 27(7): 1087-1092.
Abstract:
The reconnaissance signal recogniton of PN code-carrier FM based on Spectral Correlation (SC) method is studied, especially for Pseudo-Randorm Bi-phace Code (PRBC), SFM-PRBC and LFM-PRBC. Based on the character-extraction and analysis of the a-section of SC, the auto-classification of modulation class is investigated, and the carrier frequency and the parameter of FM are estimated. Further, the parameter of PN code are estimated. The influence of the noise and the limited-time of sampling is analyzed. Finally, the simulation shows the advantage of SC in the recognition of reconnaissance signal.
The reconnaissance signal recogniton of PN code-carrier FM based on Spectral Correlation (SC) method is studied, especially for Pseudo-Randorm Bi-phace Code (PRBC), SFM-PRBC and LFM-PRBC. Based on the character-extraction and analysis of the a-section of SC, the auto-classification of modulation class is investigated, and the carrier frequency and the parameter of FM are estimated. Further, the parameter of PN code are estimated. The influence of the noise and the limited-time of sampling is analyzed. Finally, the simulation shows the advantage of SC in the recognition of reconnaissance signal.
2005, 27(7): 1093-1097.
Abstract:
In this paper, the MIMO system model and three criteria for space-time code design are introduced. Then, according to these criteria, combining trellis-coded modulation with space-time block code, a new kind of full-diversity full-rate space-time code called Trellis-Coded Modulation Space-Time (TCMST) block code and its trellis-sphere decoding algorithm are presented. Finally, the performance merit of TCMST block code is confirmed by Monte Carlo simulations and compared with other space-time block codes.
In this paper, the MIMO system model and three criteria for space-time code design are introduced. Then, according to these criteria, combining trellis-coded modulation with space-time block code, a new kind of full-diversity full-rate space-time code called Trellis-Coded Modulation Space-Time (TCMST) block code and its trellis-sphere decoding algorithm are presented. Finally, the performance merit of TCMST block code is confirmed by Monte Carlo simulations and compared with other space-time block codes.
2005, 27(7): 1098-1100.
Abstract:
Space-Time Block Codes (STBC) is a scheme based on diversity-oriented transmission while VBLAST is another scheme based on spatial multiplexing; The performances of the two different MIMO systems are both degraded in correlated channels, however the performance of the former is better than the later. This paper proposes a trade-off scheme that the transmit antennas are divided into group meantime space-time block codes are applied to the different groups, VBLAST algorithm is used in the receiver. Simulation results show that performance of proposed scheme greatly gains over the VBLAST.
Space-Time Block Codes (STBC) is a scheme based on diversity-oriented transmission while VBLAST is another scheme based on spatial multiplexing; The performances of the two different MIMO systems are both degraded in correlated channels, however the performance of the former is better than the later. This paper proposes a trade-off scheme that the transmit antennas are divided into group meantime space-time block codes are applied to the different groups, VBLAST algorithm is used in the receiver. Simulation results show that performance of proposed scheme greatly gains over the VBLAST.
2005, 27(7): 1101-1105.
Abstract:
This paper investigates blind multiuser detection for asynchronous DS-CDMA in frequency selective Rayleigh fading channel. A method of estimating the desired signal vector is presented. The method not only exploits the characteristics of multipath propagation but also the characteristics of timing-offsets which may occur in the receiver, to facilitate the application of a blind linear filter-optimization technique to robust interference suppression. To suppress Multiuser Access Interference (MAI), a Projection-based Auxiliary Vector (PAV) algorithm is proposed. The algorithm has low computation complexity, especially suitable for fast optimization of filter vector with short data samples. It can provide efficient interference suppression in low input SINR, and shows robust performance in high input SINR.
This paper investigates blind multiuser detection for asynchronous DS-CDMA in frequency selective Rayleigh fading channel. A method of estimating the desired signal vector is presented. The method not only exploits the characteristics of multipath propagation but also the characteristics of timing-offsets which may occur in the receiver, to facilitate the application of a blind linear filter-optimization technique to robust interference suppression. To suppress Multiuser Access Interference (MAI), a Projection-based Auxiliary Vector (PAV) algorithm is proposed. The algorithm has low computation complexity, especially suitable for fast optimization of filter vector with short data samples. It can provide efficient interference suppression in low input SINR, and shows robust performance in high input SINR.
2005, 27(7): 1106-1109.
Abstract:
Efficient power control is very important in the design of cellular radio systems. In this paper, a power balancing method is proposed in Multi-Input Multi-Output (MIMO) cellular systems,and BER performance is analysed. Simulation results indicate that power balancing can decrease BER at receiver when the number of receiver antennas is greater than that of transmitter.
Efficient power control is very important in the design of cellular radio systems. In this paper, a power balancing method is proposed in Multi-Input Multi-Output (MIMO) cellular systems,and BER performance is analysed. Simulation results indicate that power balancing can decrease BER at receiver when the number of receiver antennas is greater than that of transmitter.
2005, 27(7): 1110-1113.
Abstract:
The adoption of B. Steiner channel estimation algorithm is prevalent in TD-SCDMA system. However, the estimated channel impulse responses are affected by the noise in the channel, therefore their amplitudes and delays are larger than the real channel impulse responses. Two improved algorithms are proposed, both of which set gates for the channel impulse responses. The simulation results show that both the outputs of channel estimator and the system performance are improved by adopting the gate method.
The adoption of B. Steiner channel estimation algorithm is prevalent in TD-SCDMA system. However, the estimated channel impulse responses are affected by the noise in the channel, therefore their amplitudes and delays are larger than the real channel impulse responses. Two improved algorithms are proposed, both of which set gates for the channel impulse responses. The simulation results show that both the outputs of channel estimator and the system performance are improved by adopting the gate method.
2005, 27(7): 1114-1117.
Abstract:
A new generalized sphere decoding algorithm is proposed for under-determined MIMO systems with fewer receive antennas TV than transmit antennas M. The proposed algorithm is significantly faster than the existing generalized sphere decoding algorithms. The basic idea is to partition the transmitted signal vector into two subvectors xa and xb with N-1 and M- N+l elements respectively. After some simple transformations, an outer layer Sphere Decoder (SD) can be used to choose proper xb and then use an inner layer SD to decide xa thus the whole transmitted signal vector is obtained. Simulation results show that Double Layer Sphere Decoding (DLSD) has far less complexity than the existing Generalized Sphere Decoding (GSDs).
A new generalized sphere decoding algorithm is proposed for under-determined MIMO systems with fewer receive antennas TV than transmit antennas M. The proposed algorithm is significantly faster than the existing generalized sphere decoding algorithms. The basic idea is to partition the transmitted signal vector into two subvectors xa and xb with N-1 and M- N+l elements respectively. After some simple transformations, an outer layer Sphere Decoder (SD) can be used to choose proper xb and then use an inner layer SD to decide xa thus the whole transmitted signal vector is obtained. Simulation results show that Double Layer Sphere Decoding (DLSD) has far less complexity than the existing Generalized Sphere Decoding (GSDs).
2005, 27(7): 1118-1122.
Abstract:
Multi-antenna technique is an effective means of improving performance of the downlink transmission. Both Beam-Forming (BF) and Transmit Diversity (TD) which exploit multiple antennas are attractive candidates for improving the system performance and increasing the channel capacity. In this paper, an adaptive downlink transmission scheme combining BF with TD in the closed-loop mode is proposed. And it includes two methods, one uses the diversity antenna array and is suitable for the slowly time-varying channel, and the other uses the BF antenna array and is suitable for fast time-varying channel. The transmitter can adaptively change the transmission mode between two methods according to the actual channel states. The algorithm of the adaptive scheme is investigated in the paper, and the complexity of the algorithm and its applicable environment are also analyzed. The simulation results show that the new scheme can achieve both BF gains and TD gains; while it improves the performance of the Bit Error Rate (BER), it can enhance the adaptive ability to the channel variance of the wireless system.
Multi-antenna technique is an effective means of improving performance of the downlink transmission. Both Beam-Forming (BF) and Transmit Diversity (TD) which exploit multiple antennas are attractive candidates for improving the system performance and increasing the channel capacity. In this paper, an adaptive downlink transmission scheme combining BF with TD in the closed-loop mode is proposed. And it includes two methods, one uses the diversity antenna array and is suitable for the slowly time-varying channel, and the other uses the BF antenna array and is suitable for fast time-varying channel. The transmitter can adaptively change the transmission mode between two methods according to the actual channel states. The algorithm of the adaptive scheme is investigated in the paper, and the complexity of the algorithm and its applicable environment are also analyzed. The simulation results show that the new scheme can achieve both BF gains and TD gains; while it improves the performance of the Bit Error Rate (BER), it can enhance the adaptive ability to the channel variance of the wireless system.
2005, 27(7): 1123-1126.
Abstract:
A high performance blind adaptive multiuser detection algorithm is proposed by introducing robust Kalman filter based on a compensation technique of a fictitious noise to estimate the optimal decision vector of asynchronous CDMA multiple-users receiver. This algorithm can converge rapidly, track in high accuracy and has satisfied numeric stability. Simulation results show that this algorithm can eliminate Multiple Access Interference (MAI) efficiently and is robust for numerical calculation.
A high performance blind adaptive multiuser detection algorithm is proposed by introducing robust Kalman filter based on a compensation technique of a fictitious noise to estimate the optimal decision vector of asynchronous CDMA multiple-users receiver. This algorithm can converge rapidly, track in high accuracy and has satisfied numeric stability. Simulation results show that this algorithm can eliminate Multiple Access Interference (MAI) efficiently and is robust for numerical calculation.
2005, 27(7): 1127-1130.
Abstract:
A new q-ary generalized self-shrinking generator is presented. The main difference between the new generator and the old one is the output mode. It is shown that there is good correlation between sequences in the large sequence family, and sequences are balanced in a least period. Simultaneously, the lower bounds of the least period are provided, and the family of sequences takes on a rich group structure and linear space structure.
A new q-ary generalized self-shrinking generator is presented. The main difference between the new generator and the old one is the output mode. It is shown that there is good correlation between sequences in the large sequence family, and sequences are balanced in a least period. Simultaneously, the lower bounds of the least period are provided, and the family of sequences takes on a rich group structure and linear space structure.
2005, 27(7): 1131-1135.
Abstract:
Automatic Switched Optical Network(ASON) is the key technology for the next generation optical network, and the recommendations for ASON are also developed by ITU-T, but for management plane, the related recommendations have not been constituted. In this paper, the management information mode for network layer and control plane resources are proposed based on the requirements for ASON network management. The managed object model of network layer resource could be used for the end-to-end connections management in multi-domain networks. The model for the control plane could be used for the management of control Network Elements (NEs) and control channels, this model could also be used for route areas division in control plane and configuring and performance inspecting for the control modules in the control NEs.
Automatic Switched Optical Network(ASON) is the key technology for the next generation optical network, and the recommendations for ASON are also developed by ITU-T, but for management plane, the related recommendations have not been constituted. In this paper, the management information mode for network layer and control plane resources are proposed based on the requirements for ASON network management. The managed object model of network layer resource could be used for the end-to-end connections management in multi-domain networks. The model for the control plane could be used for the management of control Network Elements (NEs) and control channels, this model could also be used for route areas division in control plane and configuring and performance inspecting for the control modules in the control NEs.
2005, 27(7): 1136-1140.
Abstract:
This paper proposes an algorithm, called Dynamic Shared Sub-Path Protection (DSSPP), for protecting a single Shared Risk Link Group (SRLG) failure in survivable WDM mesh networks. DSSPP firstly searches a primary path for a connection request, and it follows to segment the primary path into several equal length sub-paths according to the m, where the m is the length of the sub-path, and searches a SRLG-disjoint backup path for each sub-path. If two sub-paths are SRLG-disjoint, then their corresponding backup paths can share the common resources. When computing paths, DSSPP considers the load balance and the resources sharing degree, so that the paths are the minimum cost, and the resource utilization ratio can be improved and the blocking ratio can be reduced. The simulation results show that DSSPP not only can completely protect a single-SRLG failure but also can make the trade-offs between the resource utilization ratio (or blocking ratio) and the protection-switching time.
This paper proposes an algorithm, called Dynamic Shared Sub-Path Protection (DSSPP), for protecting a single Shared Risk Link Group (SRLG) failure in survivable WDM mesh networks. DSSPP firstly searches a primary path for a connection request, and it follows to segment the primary path into several equal length sub-paths according to the m, where the m is the length of the sub-path, and searches a SRLG-disjoint backup path for each sub-path. If two sub-paths are SRLG-disjoint, then their corresponding backup paths can share the common resources. When computing paths, DSSPP considers the load balance and the resources sharing degree, so that the paths are the minimum cost, and the resource utilization ratio can be improved and the blocking ratio can be reduced. The simulation results show that DSSPP not only can completely protect a single-SRLG failure but also can make the trade-offs between the resource utilization ratio (or blocking ratio) and the protection-switching time.
2005, 27(7): 1141-1146.
Abstract:
This paper addresses a Service Level Specification (SLS)-based quantitative edge-to-edge QoS management mechanism in access network. By using Ethernet Passive Optical Network(EPON), it well settles the insufficiency of bandwidth in IP, it selects a service class for user service by the evaluation algorithm of optimal ratio, because the evaluation formula of optimal ratio is based on the user behavior in market and takes into accounts burden element, price element, and performance element, it not only can support quantitative QoS in DiffServ by inducing traffic orderly distributed along the service class, but also can provide well performance with less cost. Experimental results have perfectly verified its metrics.
This paper addresses a Service Level Specification (SLS)-based quantitative edge-to-edge QoS management mechanism in access network. By using Ethernet Passive Optical Network(EPON), it well settles the insufficiency of bandwidth in IP, it selects a service class for user service by the evaluation algorithm of optimal ratio, because the evaluation formula of optimal ratio is based on the user behavior in market and takes into accounts burden element, price element, and performance element, it not only can support quantitative QoS in DiffServ by inducing traffic orderly distributed along the service class, but also can provide well performance with less cost. Experimental results have perfectly verified its metrics.
2005, 27(7): 1147-1151.
Abstract:
After studying the MAC protocol of Ad hoc network and by modifying the Wireless Token Ring Protocol (WTRP), a new uncontested Distributed Parallel Wireless Polling Access Protocol (DPWPAP) that can provide MAC QoS guarantees for Ad hoc network is presented, and the mathematical model is established by the embedded Markov chain theory and the probability generating function method. Based on it, the mean value of queue length and message waiting time are explicitly obtained. The simulation results indicate minor errors are introduced by the established system, and also show that the average delay and average queue length in DPWPAP system are much more lower than in WTRP system, the stability is enhanced highly. As a result, it is a better MAC protocol for the services that require lower delay.
After studying the MAC protocol of Ad hoc network and by modifying the Wireless Token Ring Protocol (WTRP), a new uncontested Distributed Parallel Wireless Polling Access Protocol (DPWPAP) that can provide MAC QoS guarantees for Ad hoc network is presented, and the mathematical model is established by the embedded Markov chain theory and the probability generating function method. Based on it, the mean value of queue length and message waiting time are explicitly obtained. The simulation results indicate minor errors are introduced by the established system, and also show that the average delay and average queue length in DPWPAP system are much more lower than in WTRP system, the stability is enhanced highly. As a result, it is a better MAC protocol for the services that require lower delay.
2005, 27(7): 1152-1156.
Abstract:
The requirement of high quality random numbers grows day by day, so true random number generator takes great attentions; And the appearance and development of system on a chip needs the realization of on-chip random number generator. Considering the two facts, this paper comes up with a new method of random number generator based on the noise source of PLL.The method can provide a good property: true randomness and easy realization and system integration.
The requirement of high quality random numbers grows day by day, so true random number generator takes great attentions; And the appearance and development of system on a chip needs the realization of on-chip random number generator. Considering the two facts, this paper comes up with a new method of random number generator based on the noise source of PLL.The method can provide a good property: true randomness and easy realization and system integration.
2005, 27(7): 1157-1161.
Abstract:
This paper presents a new test pattern generation technique based on ant algorithm and genetic algorithm for improving the test generation efficiency for sequential circuits. Experimental results for the sequential benchmark circuits show that the hybrid approach not only takes full advantage of utilizing both algorithms, but also overcomes their disadvantages. It can achieve higher fault coverages and more compact test sets when compared to other similar test generation algorithms, demonstrating the combined algorithm is a successful algorithm.
This paper presents a new test pattern generation technique based on ant algorithm and genetic algorithm for improving the test generation efficiency for sequential circuits. Experimental results for the sequential benchmark circuits show that the hybrid approach not only takes full advantage of utilizing both algorithms, but also overcomes their disadvantages. It can achieve higher fault coverages and more compact test sets when compared to other similar test generation algorithms, demonstrating the combined algorithm is a successful algorithm.
2005, 27(7): 1162-1166.
Abstract:
The circuit structure of a kind of PCI bus multi-user data Buffer Manager (BM) is analyzed in this paper, and typical simulating waveform is presented. The method to allocate the data buffers, port bandwidth, maximum user waiting time and minimum user buffer requirements are analyzed theoretically. The expression to calculate the minimum memory needed in the BM is given. Based on the analysis, a 128-user buffer manager is realized with XILINX XCV600EPQ240 and verified in application systems.
The circuit structure of a kind of PCI bus multi-user data Buffer Manager (BM) is analyzed in this paper, and typical simulating waveform is presented. The method to allocate the data buffers, port bandwidth, maximum user waiting time and minimum user buffer requirements are analyzed theoretically. The expression to calculate the minimum memory needed in the BM is given. Based on the analysis, a 128-user buffer manager is realized with XILINX XCV600EPQ240 and verified in application systems.
2005, 27(7): 1167-1170.
Abstract:
The coupling path of crosstalk in PCB is analyzed both in the frequency and the time domains in this paper. The influence of the coupling capacitance and the resistances near and far from the source in the victim circuit is investigated. The optimization model is derived mathematically in time domain for the 2-n circuit model. The conclusion is deduced that the maximum crosstalk is derived from the rising edge of the aggressive signal. The simulation results by use of Hyperlynx software are compared with regards to the coupling capacitance and the coupling length, which demonstrate the theoretical conclusion.
The coupling path of crosstalk in PCB is analyzed both in the frequency and the time domains in this paper. The influence of the coupling capacitance and the resistances near and far from the source in the victim circuit is investigated. The optimization model is derived mathematically in time domain for the 2-n circuit model. The conclusion is deduced that the maximum crosstalk is derived from the rising edge of the aggressive signal. The simulation results by use of Hyperlynx software are compared with regards to the coupling capacitance and the coupling length, which demonstrate the theoretical conclusion.
2005, 27(7): 1171-1173.
Abstract:
The ground penetrating radar is greatly expected as an effective tool for nondestructively sensing subsurface environment, detecting and identifying underground objects such as water pipes, power and communication lines, archaeological remains, and so on. However, conventional ground penetrating radar systems are still insufficient for practical uses with respect to reliability, resolution, detectable depth, and so forth. In order to overcome these difficulties, it is important to improve characteristics of signals to be measured. Therefore, the design and development of antennas of higher performances would be invaluable. This paper designed a bow-tie antenna loaded by lumped resistors. Results of finite difference time domain calculation show good fidelity of the wave, and exciting radiation features as well as effect of shielding. It can be widely used in ground penetrating radar and other tra-wide-band systems.
The ground penetrating radar is greatly expected as an effective tool for nondestructively sensing subsurface environment, detecting and identifying underground objects such as water pipes, power and communication lines, archaeological remains, and so on. However, conventional ground penetrating radar systems are still insufficient for practical uses with respect to reliability, resolution, detectable depth, and so forth. In order to overcome these difficulties, it is important to improve characteristics of signals to be measured. Therefore, the design and development of antennas of higher performances would be invaluable. This paper designed a bow-tie antenna loaded by lumped resistors. Results of finite difference time domain calculation show good fidelity of the wave, and exciting radiation features as well as effect of shielding. It can be widely used in ground penetrating radar and other tra-wide-band systems.
2005, 27(7): 1174-1176.
Abstract:
In this paper, the method of neural network in the computer code MATLAB is used to simulate experimental data, which is applied to the design of traveling-wave tube. Compared with the conventional method of quadratic interpolation, it is a practical method that the simulation result with the neural network is closer to the characteristics of dispersion in the test.
In this paper, the method of neural network in the computer code MATLAB is used to simulate experimental data, which is applied to the design of traveling-wave tube. Compared with the conventional method of quadratic interpolation, it is a practical method that the simulation result with the neural network is closer to the characteristics of dispersion in the test.
