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2004 Vol. 26, No. 6
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2004, 26(6): 841-845.
Abstract:
The issue of real-time coding and transmission of video over WLAN is discussed in this paper. First, a modified hybrid ARQ/FEC algorithm, based on the characteristic of video coding, which improves the performance of video transmission, is proposed. ...
The issue of real-time coding and transmission of video over WLAN is discussed in this paper. First, a modified hybrid ARQ/FEC algorithm, based on the characteristic of video coding, which improves the performance of video transmission, is proposed. ...
2004, 26(6): 846-852.
Abstract:
A new Global Rate Distortion(GRD) optimal macroblock coding mode decision scheme is introduced for the newly H.26L video compression standard. Based on the Internet packet loss model of Bernoulli and Gilbert, this R-D mode decision approach can resul...
A new Global Rate Distortion(GRD) optimal macroblock coding mode decision scheme is introduced for the newly H.26L video compression standard. Based on the Internet packet loss model of Bernoulli and Gilbert, this R-D mode decision approach can resul...
2004, 26(6): 853-858.
Abstract:
Future wireless networks promise multimedia communication and computing services for both fixed and mobile users. One of the most important challenges of wireless multimedia service for mobile users is maintaining a guaranteed quality of service over...
Future wireless networks promise multimedia communication and computing services for both fixed and mobile users. One of the most important challenges of wireless multimedia service for mobile users is maintaining a guaranteed quality of service over...
2004, 26(6): 859-863.
Abstract:
Based on the property of OFDM signal, a new carrier frequency acquisition algorithm is proposed, which employs only one block of identical time-domain training sym-bols. The proposed algorithm has good precision, low computations and large acquisitio...
Based on the property of OFDM signal, a new carrier frequency acquisition algorithm is proposed, which employs only one block of identical time-domain training sym-bols. The proposed algorithm has good precision, low computations and large acquisitio...
2004, 26(6): 864-870.
Abstract:
By analyzing the OFDM signal, a carrier frequency offset estimation algorithm for uplink of OFDM systems is proposed. The algorithm with high accuracy can be imple-mented easily, and the performance of the algorithm is almost not affected by the sub-...
By analyzing the OFDM signal, a carrier frequency offset estimation algorithm for uplink of OFDM systems is proposed. The algorithm with high accuracy can be imple-mented easily, and the performance of the algorithm is almost not affected by the sub-...
2004, 26(6): 871-875.
Abstract:
In this paper, a sub-carrier allocation scheme is proposed for the future mul-tiuser mobile multimedia communication systems, which, is based on Orthogonal Frequency Division Multiplexing(OFDM) using adaptive modulation. This scheme uses an algorithm...
In this paper, a sub-carrier allocation scheme is proposed for the future mul-tiuser mobile multimedia communication systems, which, is based on Orthogonal Frequency Division Multiplexing(OFDM) using adaptive modulation. This scheme uses an algorithm...
2004, 26(6): 876-881.
Abstract:
In this paper, a carrier offset estimation algorithm for OFDM-TDMA system is presented by taking advantage of the inherent orthogonality among OFDM subchannels. The simulation results illustrate that the algorithm offers a higher accuracy in the freq...
In this paper, a carrier offset estimation algorithm for OFDM-TDMA system is presented by taking advantage of the inherent orthogonality among OFDM subchannels. The simulation results illustrate that the algorithm offers a higher accuracy in the freq...
2004, 26(6): 882-888.
Abstract:
This paper presents a combined symbol and sampling clock synchronization method for OFDM systems. Especially, the timing correction is obtained by interpolation or decimation over sampled signal. This method utilizes the differentially modulated subc...
This paper presents a combined symbol and sampling clock synchronization method for OFDM systems. Especially, the timing correction is obtained by interpolation or decimation over sampled signal. This method utilizes the differentially modulated subc...
2004, 26(6): 889-895.
Abstract:
In this paper, an efficient and fast fault restoration mechanism based on m : n architecture with bandwidth constraints is proposed while three evaluating parameters are selected and formulated. The comparison of restoration performance, which is bas...
In this paper, an efficient and fast fault restoration mechanism based on m : n architecture with bandwidth constraints is proposed while three evaluating parameters are selected and formulated. The comparison of restoration performance, which is bas...
2004, 26(6): 896-902.
Abstract:
In Wavelength Division Multiplexing (WDM) optical networks, lightpaths are high-capacity all-optical channels. A single fiber failure can lead to the failure.of all the lightpaths traversing the fiber, and results in significant loss of traffic. Ther...
In Wavelength Division Multiplexing (WDM) optical networks, lightpaths are high-capacity all-optical channels. A single fiber failure can lead to the failure.of all the lightpaths traversing the fiber, and results in significant loss of traffic. Ther...
2004, 26(6): 903-911.
Abstract:
To obtain efficient survivability, this paper presents a novel restorable lightpath selection algorithm based on the automatically switched optical network frame. A numerical simulation is made in term of this routing selection algorithm. The result ...
To obtain efficient survivability, this paper presents a novel restorable lightpath selection algorithm based on the automatically switched optical network frame. A numerical simulation is made in term of this routing selection algorithm. The result ...
2004, 26(6): 912-916.
Abstract:
This paper proves that the longer the key of Twofish is,the smaller the differ-ential probabilities of the key-dependent S-boxes are. A new method is proposed to produce the key-dependent S-boxes. Theory and simulation results show that the XOR diffe...
This paper proves that the longer the key of Twofish is,the smaller the differ-ential probabilities of the key-dependent S-boxes are. A new method is proposed to produce the key-dependent S-boxes. Theory and simulation results show that the XOR diffe...
2004, 26(6): 917-922.
Abstract:
As the erratic performance of Extended Kalman Filter(EKF) method in passive locaiton, a new filtering method called Modified coVariance EKF(MVEKF) is put forward. It is also compared with several filtering methods mostly used in passive location and ...
As the erratic performance of Extended Kalman Filter(EKF) method in passive locaiton, a new filtering method called Modified coVariance EKF(MVEKF) is put forward. It is also compared with several filtering methods mostly used in passive location and ...
2004, 26(6): 923-927.
Abstract:
Basing on studying the principle of active contour model and some solutions to it, a new partial optimal dynamic programming contour detection algorithm is presented and the results comparable to the dynamic programming algorithm are given. Experimen...
Basing on studying the principle of active contour model and some solutions to it, a new partial optimal dynamic programming contour detection algorithm is presented and the results comparable to the dynamic programming algorithm are given. Experimen...
2004, 26(6): 928-934.
Abstract:
In this paper, a novel approach is presented for the multiuser channel identification. The approach makes use of the modulation-induced cyclostationarity and its capable of identifing individual channels of different users. By measns of the complex c...
In this paper, a novel approach is presented for the multiuser channel identification. The approach makes use of the modulation-induced cyclostationarity and its capable of identifing individual channels of different users. By measns of the complex c...
2004, 26(6): 935-939.
Abstract:
The Arithmetic Fourier Transform (AFT) is widely used because of its simple computational structure and little multiplications. But over-sampling is often needed for the implementation of AFT to meet the accuracy requirements in real applications and...
The Arithmetic Fourier Transform (AFT) is widely used because of its simple computational structure and little multiplications. But over-sampling is often needed for the implementation of AFT to meet the accuracy requirements in real applications and...
2004, 26(6): 940-944.
Abstract:
In this paper, the differential operators are introduced firstly. Then based on the characteristics of Haar wavelet transforms and the differential operators, a transmissibility algorithm is proposed and applied to the singularity measuring of 2D sig...
In this paper, the differential operators are introduced firstly. Then based on the characteristics of Haar wavelet transforms and the differential operators, a transmissibility algorithm is proposed and applied to the singularity measuring of 2D sig...
2004, 26(6): 945-952.
Abstract:
An efficient iterative lagrange multiplier approach is proposed for the design two-channel low delay perfect reconstruction filter banks. This approach has high design efficiency and can be used to design both equal-length and unequal-length filter b...
An efficient iterative lagrange multiplier approach is proposed for the design two-channel low delay perfect reconstruction filter banks. This approach has high design efficiency and can be used to design both equal-length and unequal-length filter b...
2004, 26(6): 953-958.
Abstract:
The traditional formula computing the synthetic aperture length of spotlight SAR and its localization are presented in this paper firstly. Then the new formula to com puting the synthetic aperture length of spotlight SAR is deducted on the basis of a...
The traditional formula computing the synthetic aperture length of spotlight SAR and its localization are presented in this paper firstly. Then the new formula to com puting the synthetic aperture length of spotlight SAR is deducted on the basis of a...
2004, 26(6): 959-965.
Abstract:
In this paper, a method of detecting moving targets in SAR using the match FourieT transform is introduced. The signal model and the detecting method are discussed and simulations are performed. The results of the simulations and the practices of det...
In this paper, a method of detecting moving targets in SAR using the match FourieT transform is introduced. The signal model and the detecting method are discussed and simulations are performed. The results of the simulations and the practices of det...
2004, 26(6): 966-970.
Abstract:
Combining the idea of the real-time input estimation algorithm (Feng Xinxi, et al, 1996), a novel maneuvering target model is presented based on the current statistics model. At the same times, an adaptive tracking algorithm is developed using the re...
Combining the idea of the real-time input estimation algorithm (Feng Xinxi, et al, 1996), a novel maneuvering target model is presented based on the current statistics model. At the same times, an adaptive tracking algorithm is developed using the re...
2004, 26(6): 971-978.
Abstract:
The EM algorithm, as an iterative numerical tool for computing maximum likelihood (or MAP) parameter estimates for incomplete data problem, has been used in area of target tracking, particularly in passive tracking and scenario in which real-time pro...
The EM algorithm, as an iterative numerical tool for computing maximum likelihood (or MAP) parameter estimates for incomplete data problem, has been used in area of target tracking, particularly in passive tracking and scenario in which real-time pro...
2004, 26(6): 979-983.
Abstract:
Error model and its corresponding pre-distortion calibration method for trans-mitting array are presented in this paper. According to the characteristics of transmitting array, element-pattern-based and synthesized-beam-based methods are proposed to ...
Error model and its corresponding pre-distortion calibration method for trans-mitting array are presented in this paper. According to the characteristics of transmitting array, element-pattern-based and synthesized-beam-based methods are proposed to ...
2004, 26(6): 984-988.
Abstract:
This paper proposes a novel modulation mode named Pulse-cycle Skip Modu-lation(PSM) in switching converter and analyzes its principle and characteristics. The state equations, modulation factor, response speed and the efficiency of PSM are also descr...
This paper proposes a novel modulation mode named Pulse-cycle Skip Modu-lation(PSM) in switching converter and analyzes its principle and characteristics. The state equations, modulation factor, response speed and the efficiency of PSM are also descr...
2004, 26(6): 989-994.
Abstract:
In this paper a novel adaptive semi-blind beamforming algorithm is proposed for OFDM-MIMO systems. First the nonlinear neural networks combined with maximized mutual information rule are used for estimating the coarse weights of beamformer, then the ...
In this paper a novel adaptive semi-blind beamforming algorithm is proposed for OFDM-MIMO systems. First the nonlinear neural networks combined with maximized mutual information rule are used for estimating the coarse weights of beamformer, then the ...
2004, 26(6): 995-999.
Abstract:
In this paper, based on the characteristics of Turbo codes and Trellis Coded Modulation (TCM), an improved method Turbo Trellis Coded Modulation (TTCM) is pre-sented and analyzed over flat Rayleigh fading channels in image transmission with two typic...
In this paper, based on the characteristics of Turbo codes and Trellis Coded Modulation (TCM), an improved method Turbo Trellis Coded Modulation (TTCM) is pre-sented and analyzed over flat Rayleigh fading channels in image transmission with two typic...
2004, 26(6): 1000-1004.
Abstract:
Segment dropping is a novel contention resolution proposed recently. Firstly, the drawback of tail-dropping contention resolution is analyzed in this paper. Then a mod-ified head-dropping policy is proposed. This policy drops the head of contending b...
Segment dropping is a novel contention resolution proposed recently. Firstly, the drawback of tail-dropping contention resolution is analyzed in this paper. Then a mod-ified head-dropping policy is proposed. This policy drops the head of contending b...
2004, 26(6): 1005-1008.
Abstract:
A dynamic secret sharing scheme based on discrete logarithms and factorization is proposed in this paper. It has the following advanced properties: (1) The dealer can renew system secrets without renewing the shadows of the participants; (2) When the...
A dynamic secret sharing scheme based on discrete logarithms and factorization is proposed in this paper. It has the following advanced properties: (1) The dealer can renew system secrets without renewing the shadows of the participants; (2) When the...
