Please wait a minute...

Current Issue

    25 May 2013, Volume 34 Issue 5
    Analysis of MIMO antenna array based on electromagnetic vector sensor
    2013, 34(5):  1-11. 
    Asbtract ( 1809 )   Knowledge map   
    Related Articles | Metrics
    EVS(electromagnetic vetor sensor) signal processing method was combined with traditional MIMO signal processing method and three-dimensional channel model of multi-antenna array was set up. The algorithm of multiple signal classification (MUSIC) was adopted to make spatial spectrum estimation for direction of arrival (DOA) signal, analytical expressions of three-dimensional spatial channel was derived base on EVS for MIMO receiver system and the relationship between EVS signal processing and MIMO multipath channel correlation was clarified. To compare with traditional MIMO antenna array, EVS array possesses abilities of obtaining multidimensional polarization information, processing spatial and polarization domain for arrival signal and degrading effects of spatial factors on MIMO channel capacity. Theoretical analysis and simulation results indicate that EVS array provide more advantages than traditional scalar sensor array on enhancing MIMO system performance.
    academic paper
    Analysis of MIMO antenna array based on electromagnetic vector sensor
    Jie ZHOU,Lin QIU,Kikuchi HISAKAZU
    2013, 34(5):  1-11.  doi:10.3969/j.issn.1000-436x.2013.05.001
    Asbtract ( 264 )   HTML ( 2)   PDF (4022KB) ( 619 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    EVS(electromagnetic vetor sensor) signal processing method was combined with traditional MIMO signal processing method and three-dimensional channel model of multi-antenna array was set up.The algorithm of multiple signal classification (MUSIC) was adopted to make spatial spectrum estimation for direction of arrival (DOA) signal,analytical expressions of three-dimensional spatial channel was derived base on EVS for MIMO receiver system and the relationship between EVS signal processing and MIMO multipath channel correlation was clarified.To compare with tra-ditional MIMO antenna array,EVS array possesses abilities of obtaining multidimensional polarization information,processing spatial and polarization domain for arrival signal and degrading effects of spatial factors on MIMO channel capacity.Theoretical analysis and simulation results indicate that EVS array provide more advantages than traditional scalar sensor array on enhancing MIMO system performance.

    Multinomial subjective logic based extended trust propagation model
    2013, 34(5):  2-19. 
    Asbtract ( 917 )   Knowledge map   
    Related Articles | Metrics
    In order to improve the accurateness of trust evaluation and the applicability of subjective logic, a multinomial subjective logic based extended trust propagation model (MSL-ETPM) was presented, which is composed of trust fusion and trust transitivity. Making the fused opinion more accurate and more in line with the intuitive judgment of human, reputation-based fusion operator of multinomial opinions takes effects of the reputation value and observation circumstance into consideration. Trust transitivity interprets multinomial opinion transitivity as meaning that transitivity process is binomial logical opinion and transitivity information is multinomial opinion, giving trust transitivity formula of multinomial opinion and proving related theorem. Finally, the accuracy and adaptability of the model are put to the proof by example analysis.
    Hiss noise reduction method used for audio signals based on AAC bit-stream
    2013, 34(5):  3-30. 
    Asbtract ( 1001 )   Knowledge map   
    Related Articles | Metrics
    A hiss noise reduction method used for audio signals based on AAC bit-stream in compressed domain was proposed. The input was AAC bit-stream derived from noisy audio signals, and the output was the enhanced AAC bit-stream used for decoder. First, Hiss noise was estimated by modified median absolute deviation (MMAD). Second, the auditory masking threshold and the masking parameters were calculated by modified discrete Flourier transform (MDFT). Finally, the parametric soft-thresholding method was employed to obtain the enhanced AAC bit-stream which was used to get the enhanced audio signals at AAC decoder. The objective and subjective quality testing results indicate that the proposed algorithm can effectively remove the Hiss noise derived from AAC bit-stream of audio signals and obviously outperforms the existing hiss noise reduction methods.
    Analyzing the trust chain of trusted virtualization platform based on the extended LS2
    2013, 34(5):  4-41. 
    Asbtract ( 852 )   Knowledge map   
    Related Articles | Metrics
    Considering the effective formal analysis for the trust chain of the trusted virtualization platform, a trust chain model which includes the virtual machine and the virtual root of trust, was proposed firstly with the detail definition of the trusted properties. Through extending theLS2, it verified the correctness and uniqueness of the trust chain formally under some conditions. Analysis for the photosystem shows the generality of the proposed trust chain model and the validity of the analysis method based on the extended LS2.
    Semi-supervised Gaussian process classification algorithm addressing the class imbalance
    2013, 34(5):  5-51. 
    Asbtract ( 945 )   Knowledge map   
    Related Articles | Metrics
    The traditional supervised learning is difficult to deal with real-world datasets with less labeled information when the training sets class is imbalanced. Therefore, a new semi-supervised Gaussian process classification of addressing was proposed. The semi-supervised Gaussian process was realized by calculating the posterior probability to obtain more accurate and credible labeled data, and embarking from self-training semi-supervised methods to add class label into the unlabeled data. The algorithm makes the distribution of training samples relatively balance, so the classifier can adaptively optimized to obtain better effect of classification. According to the experimental results, when the circumstances of training set are class imbalance and much lack of label information, The algorithm improves the accuracy by obtaining effective labeled in comparison with other related works and provides a new idea for addressing the class imbalance is demonstrated.
    Secure anonymous authentication scheme based on elliptic curve and zero-knowledge proof in VANET
    2013, 34(5):  6-61. 
    Asbtract ( 902 )   Knowledge map   
    Related Articles | Metrics
    A secure anonymous authentication scheme was proposed based on elliptic curve and zero-knowledge proof, which adopts a bidirectional anonymous authentication algorithm to preserve users’ privacy during the certification process. In the case of a high density traffic scenario, a message aggregation technology was proposed to realize fast authentication by the assistant of RSU, and to avoid the loss of massive messages unauthenticated promptly. The simulation and analytical results show that the proposed scheme yields a much better performance than previously reported counterparts with lower communication overhead, message loss rate and message delay.
    Noise-robust linear prediction analysis of speech based on super-Gaussian excitation
    2013, 34(5):  7-70. 
    Asbtract ( 712 )   Knowledge map   
    Related Articles | Metrics
    To overcome the problem that the performance of the traditional linear prediction (LP) analysis of speech deteriorates significantly in the presence of background noise, a novel algorithm for robust LP analysis of speech based on super-Gaussian excitation was proposed. The excitation noise of LP was modeled as a Student-t distribution, which was shown to be super-Gaussian. Then a novel probabilistic graphical model for robust LP analysis of speech was built by incorporating the effect of additive noise explicitly. Furthermore, variational Bayesian inference was adopted to approximate the intractable posterior distributions of the model parameters, based on which the LP coefficients of the noisy speech were estimated iteratively. The experimental results show that the developed algorithm performs well in terms of LP coefficients estimation of speech and is much more robust to ambient noise than several other algorithms.
    M-estimate like correlation based algorithm for direction of arrival estimation under alpha-stable environments
    2013, 34(5):  8-78. 
    Asbtract ( 830 )   Knowledge map   
    Related Articles | Metrics
    A novel class of bounded statistics, namely, the M-estimate like correlation (MELC) for independently identical distributed symmetric alpha-stable ( ) random variables was defined. Based on the MELC matrix for the array sensor outputs, a new algorithm for direction of arrival (DOA) estimation in the presence of complex noise was proposed. The comprehensive Monte-Carlo simulation results show that the MELC-MUSIC algorithm not only outperforms the fractional lower order statistics (FLOS) based MUSIC algorithms under low SNR conditions and multi-source signals environment, but also is robust with circular and noncircular signals.
    Novel method of spread spectrum communication
    2013, 34(5):  9-87. 
    Asbtract ( 863 )   Knowledge map   
    Related Articles | Metrics
    As the bandwidth efficiency of traditional spread spectrum modulation is quite low, a novel spread spectrum communication method, which uses the relative position of the spread spectrum modulation symbol to carry information was presented, and the method establishes the relationship between the information transfer rate and the spreading code or the transmission bandwidth. Theoretical analysis and simulation results show that the modulation method can not only greatly improve the bandwidth efficiency of the spread spectrum system, but also effectively combat broadband, narrowband or other spread spectrum interference. This method provides some novel ideas for the future research of spread spectrum communications.
    Anti-frequency-offset algorithm on single-channel blind separation of burst GMSK mixed signals
    2013, 34(5):  10-95. 
    Asbtract ( 845 )   Knowledge map   
    Related Articles | Metrics
    A per-survivor processing (PSP) based anti-frequency-offset algorithm was proposed for single-channel blind separation of burst GMSK mixed signals. The algorithm traces the phase changes caused by frequency offset and channel changes caused by other matters separately, which remarkably tones up the capacity against frequency offset. Simulation results show that the proposed algorithm can work well even when the unitary frequency offset (compared to symbol rate ) grows up to 1.5×10?2, while the traditional PSP algorithm needs the unitary frequency offset less than 2.0×10?4. Furthermore, the proposed algorithm has no need for phase initialization, and a loss of only 1dB on performance can be achieved in comparison with the traditional PSP algorithm.
    Performance analysis and optimal design of MU-MIMO transmission scheme based on IEEE 802.11ac
    2013, 34(5):  11-106. 
    Asbtract ( 1315 )   Knowledge map   
    Related Articles | Metrics
    The recent IEEE 802.11ac adopted a novel multi-user access technique, which was the downlink multi-user MIMO (MU-MIMO) transmission. This was very different from the former IEEE 802.11 standard’s protocols. The MU-MIMO transmission technique in 802.11ac draft was studied and proposed some optimal designs. Finally, the performance of the IEEE 802.11ac MU-MIMO transmission schemes and gives the simulations. The simulation results show that the proposal transmission schemes can achieve gains of BER and throughput in theory and simulations.
    Time-frequency analysis of freqency-hopping signals based on sparse recovery
    2013, 34(5):  12-112. 
    Asbtract ( 816 )   Knowledge map   
    Related Articles | Metrics
    To overcome the common shortcomings shared by the existing methods: weak suppression noise interference and feeble performance of time-frequency concentration, a novel time-frequency analysis method based on sparse representation was developed , which could get clear and concentrate time-frequency representation. Firstly, the unconstrained sparse representation model of FH signals was established according to the punish function theory. Then, the guideline of punish parameters were analysed theoretically and got time-frequency representation by sloving the optimization problem used approximate l0 norm finally. The simulation results show that this method is capable of getting clear time-frequency pattern.
    academic paper
    Multinomial subjective logic based extended trust propagation model
    Jun-feng TIAN,Li-juan WU
    2013, 34(5):  12-19.  doi:10.3969/j.issn.1000-436x.2013.05.002
    Asbtract ( 301 )   HTML ( 7)   PDF (1137KB) ( 984 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    In order to improve the accurateness of trust evaluation and the applicability of subjective logic,a multinomial subjective logic based extended trust propagation model (MSL-ETPM) was presented,which was composed of trust fu-sion and trust transitivity.Making the fused opinion more accurate and more in line with the intuitive judgment of human,reputation-based fusion operator of multinomial opinions takes effects of the reputation value and observation circum-stance into consideration.Trust transitivity interprets multinomial opinion transitivity as meaning that transitivity process is binomial logical opinion and transitivity information is multinomial opinion,giving trust transitivity formula of multi-nomial opinion and proving related theorem.Finally,the accuracy and adaptability of the model are put to the proof by example analysis.

    Chaos-based encryption and message authentication algorithm for wireless sensor networks
    2013, 34(5):  13-120. 
    Asbtract ( 883 )   Knowledge map   
    Related Articles | Metrics
    As for the traditional digital chaos-based scheme being not directly applicable for WSN because some sensor node does not support the float type of computation, integer chaotic maps and its block encryption schemes are firstly introduced, and then a novel chaos-based message authentication code (MAC) scheme was proposed, which was length changeable with high-level hybrid chaotic security. At last, a security application solution for data communication on WSN employing the proposed chaos-based schemes is presented, and the performance evaluation on the real-world Mica2 node is analyzed to show that the new security solution is more applicable for WSN than the current most popular security scheme, TinySec.
    Optimization design and simplified decoding for short frame CCPM
    2013, 34(5):  14-125. 
    Asbtract ( 795 )   Knowledge map   
    Related Articles | Metrics
    Considering the demand of burst communications, optimization and simplified decoding for coded GMSK system in short frame was focused on to give an optimum proposal of C2PM system. Simplified demodulator, optimized generation polynomial of the convolution code and matched interleavers were discussed. Simulation results show that for coded GMSK system under AWGN, the performance is better than individual convolution code. Especially when BER is 1×10-5, it performs better than Turbo code and LDPC code with the same frame length, and there is no error floor occurring. Finally, complexity analysis shows that the coded GMSK system has lower implementation complexity in comparison with the commonly used convolution code, Turbo code and LDPC code.
    Network-assisted optimal rate control methods in cognitive networks
    2013, 34(5):  15-135. 
    Asbtract ( 795 )   Knowledge map   
    Related Articles | Metrics
    Orienting the multi-rate cognitive networks, overcoming the typical characteristics of dynamics to implement the autonomy and rationality of rate control, first the rate control framework based on the presented improved IEEE 1900.4 architecture was proposed. Meanwhile, different scaled rate control schemes on different levels were investigated. Then, the real-time rate control problem on the terminal we concentrate on. Most importantly, both the distributed rate selection of TRM towards RNRM and the centralized rate allocation of RNRM to TRM were investigated. Simulation results show that the latter can achieve 60% utility and certain fairness improvements, in addition, the rationality and fairness guaranteed by the newly-built pricing function is verified.
    Topology control algorithm backing for network coding in cognitive wireless ad hoc networks
    2013, 34(5):  16-142. 
    Asbtract ( 805 )   Knowledge map   
    Related Articles | Metrics
    In order to study the limited bandwidth resource in cognitive wireless ad hoc network, a topology control algorithm backing for network coding was proposed. The algorithm was mainly composed of three phases. In the stage of initial topology construction, the algorithm used the shortest path algorithm to construct topology for unicast services, used the shortest path algorithm based on network coding to construct topology for multicast services. In the stage of topology optimization, the algorithm deleted links which met certain conditions one by one to optimize the topology. In the stage of topology recovery, the algorithm used the least cost links which were not in the path cluster including failed links to recover network connectivity. Simulation results show that the proposed algorithm can improve the spatial reuse of radio resource and enhance network invulnerability.
    Detecting DNS-based covert channel on live traffic
    2013, 34(5):  17-151. 
    Asbtract ( 1101 )   Knowledge map   
    Related Articles | Metrics
    To propose an effective detection method for DNS-based covert channel, traffic characteristics are thoroughly studied. 12 features are extracted from DNS packets to distinguish covert channels from legitimate DNS queries. Statistical characteristics of these features are used as input of the machine learning classifier. Experimental results show that the decision tree model detects all 22 covert channels used in training, and is capable of detecting untrained covert channels. Several DNS tunnels were detected during the evaluation on campus network’s live DNS traffic.
    Review on molecular communication
    2013, 34(5):  18-167. 
    Asbtract ( 1347 )   Knowledge map   
    Related Articles | Metrics
    Bio-inspired molecular communication (MC) is a kind of communication technology using biochemical molecules as the information carrier and applied to interconnect nano-machines to constitute the distributed nano-networks. The definition and properties of MC, applications of nano-networks based on MC, important research activities and projects of MC were generalized. With particularly concerning the propagating mechanism of information molecules, the architecture of MC system was introduced. From the aspects of the design and implementation of system, theory research and nano-networks based on MC, the status of current research and development of MC was summarized and analyzed, in addition, future research trends was prospected.
    Research on content distribution mechanism of MP2P networks
    2013, 34(5):  19-175. 
    Asbtract ( 826 )   Knowledge map   
    Related Articles | Metrics
    In consideration of the current MP2P network disturbance from frequent location changes of the mobile nodes, the limited computing power and storage capacity, a flexible strategy of partition management by assigning different functions to nodes according to some standards, regarding a subnet as a unit and using super-nodes to manage subnets were proposed. In order to speed up the data transmission and replacement efficiency, data was processed with partial network coding technology. Additionally, a trans-subnet query algorithm was proposed to link subnets, conduct information exchange between subnets and resource location. Results of the experiment manifested that this strategy can efficiently increase the resource download success rate and hit rate, reduce the average delay, improve the content distribution efficiency of MP2P networks, and simultaneously enhance system robustness.
    Neighbor selection algorithm in cloud-assistant P2P-VoD system
    2013, 34(5):  20-183. 
    Asbtract ( 709 )   Knowledge map   
    Related Articles | Metrics
    A neighbor selection algorithm was proposed which was composed of sub-algorithms of peer selection and chunk selection. The peer selection algorithm assured that the peers could find the neighbors providing the video data at a high probability. The chunk selection algorithm helped peers choose the methods of downloading data, from which the data chunks could be used at a high availability. The experiment demonstrates that the algorithm can further decrease the server bandwidth costs and the refusal rate of peers’ requisition, and improve the download rate of peers.
    academic paper
    Hiss noise reduction method used for audio signals based on AAC bit-stream
    Feng DENG,Chang-chun BAO,Feng BAO
    2013, 34(5):  20-30.  doi:10.3969/j.issn.1000-436x.2013.05.003
    Asbtract ( 290 )   HTML ( 2)   PDF (1950KB) ( 573 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    A hiss noise reduction method used for audio signals based on AAC bit-stream in compressed domain was proposed.The input was AAC bit-stream derived from noisy audio signals,and the output was the enhanced AAC bit-stream used for decoder.First,Hiss noise was estimated by modified median absolute deviation (MMAD).Second,the auditory masking threshold and the masking parameters were calculated by modified discrete Flourier transform (MDFT).Finally,the parametric soft-thresholding method was employed to obtain the enhanced AAC bit-stream which was used to get the enhanced audio signals at AAC decoder.The objective and subjective quality testing results indicate that the proposed algorithm can effectively remove the Hiss noise derived from AAC bit-stream of audio signals and ob-viously outperforms the existing hiss noise reduction methods.

    Secure network coding scheme for scalable video streaming
    2013, 34(5):  21-191. 
    Asbtract ( 811 )   Knowledge map   
    Related Articles | Metrics
    With the purpose to achieve hierarchical security levels for scalable video streaming in heterogeneous networks, random function was used to randomize parts of the video streaming in each layer. Network coding scheme was also used to resist known-plaintext attacks. Moreover, network encoder was studied. Ordered random linear network encoder was designed for scalable video transmission. It could achieve scalability in security levels with few random operations and reduce communication overhead. Analysis shows that the scheme could effectively increase the network throughput.
    Research on PDE-based adaptive anisotropic image registration
    2013, 34(5):  22-199. 
    Asbtract ( 878 )   Knowledge map   
    Related Articles | Metrics
    A PDE-based adaptive anisotropic model for image registration was proposed to solve the problem that traditional optical flow brings on the image blurring and details losing. The new model introduces adaptivity diffusion filter to image registration, and defines anisotropic diffusion function with the ability of preserving image structure as the regularization term; the data term use a non-quadratic penalty function with the assumption in brightness constant to improve the robust of the model. The experimental results show that the model can efficiently protect the image structure and achieve accurate registration of the complex image like brain.
    ICFF: a cloud forensics framework under the IaaS model
    2013, 34(5):  23-206. 
    Asbtract ( 993 )   Knowledge map   
    Related Articles | Metrics
    Technical challenges of cloud forensics was summarized and a forensics framework under an infrastructure as a service(IaaS) cloud model called ICFF was proposed. Then, this framework on the open source IaaS cloud platform Eucalyptus was implemented. Finally, a test case to demonstrate the effectiveness of ICFF was designed. Experiments show that the framework can obtain evidence data in cloud platform effectively and efficiently.
    academic paper
    Analyzing the trust chain of trusted virtualization platform based on the extended LS2
    De-xian CHANG,Deng-guo FENG,Yu QIN,Qian-ying ZHANG
    2013, 34(5):  31-41.  doi:10.3969/j.issn.1000-436x.2013.05.004
    Asbtract ( 274 )   HTML ( 3)   PDF (1396KB) ( 426 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    Considering the effective formal analysis for the trust chain of the trusted virtualization platform,a trust chain model which includes the virtual machine and the virtual root of trust,was proposed firstly with the detail definition of the trusted properties.Through extending the LS2,it verified the correctness and uniqueness of the trust chain formally under some conditions.Analysis for the photosystem shows the generality of the proposed trust chain model and the va-lidity of the analysis method based on the extended LS2.

    Semi-supervised Gaussian process classification algorithm addressing the class imbalance
    Zhan-guo XIA,Shi-xiong XIA,Shi-yu CAI,Ling WAN
    2013, 34(5):  42-51.  doi:10.3969/j.issn.1000-436x.2013.05.005
    Asbtract ( 412 )   HTML ( 5)   PDF (2186KB) ( 953 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    The traditional supervised learning is difficult to deal with real-world datasets with less labeled information when the training sets class is imbalanced.Therefore,a new semi-supervised Gaussian process classification of address-ing was proposed.The semi-supervised Gaussian process was realized by calculating the posterior probability to obtain more accurate and credible labeled data,and embarking from self-training semi-supervised methods to add class label into the unlabeled data.The algorithm makes the distribution of training samples relatively balance,so the classifier can adaptively optimized to obtain better effect of classification.According to the experimental results,when the circum-stances of training set are class imbalance and much lack of label information,The algorithm improves the accuracy by obtaining effective labeled in comparison with other related works and provides a new idea for addressing the class im-balance is demonstrated.

    Noise-robust linear prediction analysis of speech based on super-Gaussian excitation
    Bin ZHOU,Xia ZOU,Xiong-wei ZHANG,Gai-hua ZHAO
    2013, 34(5):  52-61.  doi:10.3969/j.issn.1000-436x.2013.05.007
    Asbtract ( 240 )   HTML ( 0)   PDF (1635KB) ( 370 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    To overcome the problem that the performance of the traditional linear prediction (LP) analysis of speech dete-riorates significantly in the presence of background noise,a novel algorithm for robust LP analysis of speech based on super-Gaussian excitation was proposed.The excitation noise of LP was modeled as a Student-t distribution,which was shown to be super-Gaussian.Then a novel probabilistic graphical model for robust LP analysis of speech was built by in-corporating the effect of additive noise explicitly.Furthermore,variational Bayesian inference was adopted to approxi-mate the intractable posterior distributions of the model parameters,based on which the LP coefficients of the noisy speech were estimated iteratively.The experimental results show that the developed algorithm performs well in terms of LP coefficients estimation of speech and is much more robust to ambient noise than several other algorithms.

    M-estimate like correlation based algorithm for direction of arrival estimation under alpha-stable environments
    Jin-feng ZHANG,Tian-shuang QIU,Ai-min SONG,Hong TANG,Na WANG
    2013, 34(5):  71-78.  doi:10.3969/j.issn.1000-436x.2013.05.008
    Asbtract ( 304 )   HTML ( 3)   PDF (1267KB) ( 313 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    A novel class of bounded statistics,namely,the M-estimate like correlation (MELC) for independently identi-cal distributed symmetric alpha-stable (SαS) random variables was defined.Based on the MELC matrix for the array sensor outputs,a new algorithm for direction of arrival (DOA) estimation in the presence of complex SαS noise was proposed.The comprehensive Monte-Carlo simulation results show that the MELC-MUSIC algorithm not only outper-forms the fractional lower order statistics (FLOS) based MUSIC algorithms under low SNR conditions and multi-source signals environment,but also is robust with circular and noncircular signals.

    Novel method of spread spectrum communication
    Jia-fang KANG,Hong-xing WANG,Zhi-yong ZHAO,Zhong-yang MAO,Xi-guo LIU,Chuan-hui1 LIU
    2013, 34(5):  79-87.  doi:10.3969/j.issn.1000-436x.2013.05.009
    Asbtract ( 405 )   HTML ( 5)   PDF (1082KB) ( 581 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    As the bandwidth efficiency of traditional spread spectrum modulation is quite low,a novel spread spectrum communication method,which uses the relative position of the spread spectrum modulation symbol to carry information was presented,and the method establishes the relationship between the information transfer rate and the spreading code or the transmission bandwidth.Theoretical analysis and simulation results show that the modulation method can not only greatly improve the bandwidth efficiency of the spread spectrum system,but also effectively combat broadband,narrow-band or other spread spectrum interference.This method provides some novel ideas for the future research of spread spectrum communications.

    Anti-frequency-offset algorithm on single-channel blind separation of burst GMSK mixed signals
    Can-hui LIAO,Shi-long TU,Jian WAN
    2013, 34(5):  88-95.  doi:10.3969/j.issn.1000-436x.2013.05.010
    Asbtract ( 284 )   HTML ( 2)   PDF (1288KB) ( 556 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    A per-survivor processing (PSP) based anti-frequency-offset algorithm was proposed for single-channel blind separation of burst GMSK mixed signals.The algorithm traces the phase changes caused by frequency offset and channel changes caused by other matters separately,which remarkably tones up the capacity against frequency offset.Simulation results show that the proposed algorithm can work well even when the unitary frequency offset (compared to symbol rate ) grows up to 1.5×10?2,while the traditional PSP algorithm needs the unitary frequency offset less than 2.0×10?4.Further-more,the proposed algorithm has no need for phase initialization,and a loss of only 1dB on performance can be achieved in comparison with the traditional PSP algorithm.

    Performance analysis and optimal design of MU-MIMO transmission scheme based on IEEE 802.11ac
    Bao-feng JI,Kang SONG,Yong-ming HUANG,Lv-xi YANG
    2013, 34(5):  96-106.  doi:10.3969/j.issn.1000-436x.2013.05.011
    Asbtract ( 273 )   HTML ( 8)   PDF (1241KB) ( 1224 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    The recent IEEE 802.11ac adopted a novel multi-user access technique,which was the downlink multi-user MIMO (MU-MIMO) transmission.This was very different from the former IEEE 802.11 standard's protocols.The MU-MIMO transmission technique in IEEE 802.11ac draft was studied and proposed some optimal designs.Finally,the performance of the IEEE 802.11ac MU-MIMO transmission schemes and gives the simulations.The simulation results show that the proposal transmission schemes can achieve gains of BER and throughput in theory and simulations.

    Time-frequency analysis of freqency-hopping signals based on sparse recovery
    Zhi-chao SHA,Zhi-tao HUANG,Yi-yu ZHOU,Jun-hua WANG
    2013, 34(5):  107-112.  doi:10.3969/j.issn.1000-436x.2013.05.012
    Asbtract ( 262 )   HTML ( 3)   PDF (2375KB) ( 720 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    To overcome the common shortcomings shared by the existing methods: weak suppression noise interference and feeble performance of time-frequency concentration,a novel time-frequency analysis method based on sparse repre-sentation was developed,which could get clear and concentrate time-frequency representation.Firstly,the unconstrained sparse representation model of FH signals was established according to the punish function theory.Then,the guideline of punish parameters were analysed theoretically and got time-frequency representation by sloving the optimization problem used approximate l0norm finally.The simulation results show that this method is capable of getting clear time-frequency pattern.

    Technical Report
    Chaos-based encryption and message authentication algorithm for wireless sensor network
    Tie-ming CHEN,Liang GE
    2013, 34(5):  113-120.  doi:10.3969/j.issn.1000-436x.2013.05.013
    Asbtract ( 250 )   HTML ( 2)   PDF (1306KB) ( 462 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    As for the traditional digital chaos-based scheme being not directly applicable for WSN because some sensor node does not support the float type of computation,integer chaotic maps and its block encryption schemes are firstly in-troduced,and then a novel chaos-based message authentication code (MAC) scheme was proposed,which was length changeable with high-level hybrid chaotic security.At last,a security application solution for data communication on WSN employing the proposed chaos-based schemes is presented,and the performance evaluation on the real-world Mica2 node is analyzed to show that the new security solution is more applicable for WSN than the current most popular security scheme,TinySec.

    Optimization design and simplified decoding for short frame CCPM
    Xiao-jie DAI,Ya-feng ZHAN
    2013, 34(5):  121-125.  doi::10.3969/j.issn.1000-436x.2013.05.014
    Asbtract ( 138 )   HTML ( 0)   PDF (474KB) ( 272 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    Considering the demand of burst communications,optimization and simplified decoding for coded GMSK sys-tem in short frame was focused on to give an optimum proposal of C2PPM system.Simplified demodulator,optimized generation polynomial of the convolution code and matched interleavers were discussed.Simulation results show that for coded GMSK system under AWGN,the performance is better than individual convolution code.Especially when BER is 1×10-5,it performs better than Turbo code and LDPC code with the same frame length,and there is no error floor occur-ring.Finally,complexity analysis shows that the coded GMSK system has lower implementation complexity in compari-son with the commonly used convolution code,Turbo code and LDPC code.

    Network-assisted optimal rate control methods in cognitive networks
    Chun-gang YANG,Min SHENG,Yan-jie DONG,Jian-dong LI,Hong-yan LI,Qin LIU
    2013, 34(5):  126-135.  doi:10.3969/j.issn.1000-436x.2013.05.015
    Asbtract ( 199 )   HTML ( 0)   PDF (1299KB) ( 568 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    Orienting the multi-rate cognitive networks,overcoming the typical characteristics of dynamics to implement the autonomy and rationality of rate control,first the rate control framework based on the presented improved IEEE 1900.4 architecture was proposed.Meanwhile,different scaled rate control schemes on different levels were investigated.Then,the real-time rate control problem on the terminal we concentrate on.Most importantly,both the distributed rate selection of TRM towards RNRM and the centralized rate allocation of RNRM to TRM were investigated.Simulation results show that the latter can achieve 60% utility and certain fairness improvements,in addition,the rationality and fairness guaranteed by the newly-built pricing function is verified.

    Topology control algorithm backing for network coding in cognitive wireless ad hoc networks
    Jun LIU,Qian SUN,Ying-mei WANG,Ning YE,Ming-bo SHA
    2013, 34(5):  136-142.  doi:10.3969/j.issn.1000-436x.2013.05.016
    Asbtract ( 331 )   HTML ( 3)   PDF (783KB) ( 406 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    In order to study the limited bandwidth resource in cognitive wireless ad hoc network,a topology control algo-rithm backing for network coding was proposed.The algorithm was mainly composed of three phases.In the stage of ini-tial topology construction,the algorithm used the shortest path algorithm to construct topology for unicast services,used the shortest path algorithm based on network coding to construct topology for multicast services.In the stage of topology optimization,the algorithm deleted links which met certain conditions one by one to optimize the topology.In the stage of topology recovery,the algorithm used the least cost links which were not in the path cluster including failed links to recover network connectivity.Simulation results show that the proposed algorithm can improve the spatial reuse of radio resource and enhance network invulnerability.

    Detecting DNS-based covert channel on live traffic
    Si-yu ZHANG,Fu-tai1 ZOU,Lu-hua WANG,Ming CHEN
    2013, 34(5):  143-151.  doi:10.3969/j.issn.1000-436x.2013.05.017
    Asbtract ( 640 )   HTML ( 35)   PDF (1150KB) ( 3849 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    To propose an effective detection method for DNS-based covert channel,traffic characteristics were thor-oughly studied.12 features were extracted from DNS packets to distinguish covert channels from legitimate DNS queries.Statistical characteristics of these features are used as input of the machine learning classifier.Experimental results show that the decision tree model detects all 22 covert channels used in training,and is capable of detecting untrained covert channels.Several DNS tunnels were detected during the evaluation on campus network's live DNS traffic.

    Overview
    Review on molecular communication
    Zuo-peng LI,Jing ZHANG,Shao-bin CAI,Yong WANG,Jun NI
    2013, 34(5):  152-167.  doi:10.3969/j.issn.1000-436x.2013.05.018
    Asbtract ( 715 )   HTML ( 45)   PDF (818KB) ( 1843 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    Bio-inspired molecular communication (MC) is a kind of communication technology using biochemical mole-cules as the information carrier and applied to interconnect nano-machines to constitute the distributed nano-networks.The definition and properties of MC,applications of nano-networks based on MC,important research activities and pro-jects of MC were generalized.With particularly concerning the propagating mechanism of information molecules,the architecture of MC system was introduced.From the aspects of the design and implementation of system,theory research and nano-networks based on MC,the status of current research and development of MC was summarized and analyzed,in addition,future research trends was prospected.

    Academic communication
    Research on content distribution mechanism of MP2P networks
    Guo-yin ZHANG,Lu LI,Jian-guo SUN,Xiang-hui WANG
    2013, 34(5):  168-175.  doi:10.3969/j.issn.1000-436x.2013.05.019
    Asbtract ( 231 )   HTML ( 0)   PDF (916KB) ( 382 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    In consideration of the current MP2P network disturbance from frequent location changes of the mobile nodes,the limited computing power and storage capacity,a flexible strategy of partition management by assigning different functions to nodes according to some standards,regarding a subnet as a unit and using super-nodes to manage subnets were proposed.In order to speed up the data transmission and replacement efficiency,data was processed with partial network coding technology.Additionally,a trans-subnet query algorithm was proposed to link subnets,conduct informa-tion exchange between subnets and resource location.Results of the experiment manifested that this strategy can effi-ciently increase the resource download success rate and hit rate,reduce the average delay,improve the content distribu-tion efficiency of MP2P networks,and simultaneously enhance system robustness.

    Neighbor selection algorithm in cloud-assistant P2P-VoD system
    Xin CONG,Kai SHUANG,Sen SU,Fang-chun YANG,Xin SUN
    2013, 34(5):  176-183.  doi:10.3969/j.issn.1000-436x.2013.05.020
    Asbtract ( 262 )   HTML ( 0)   PDF (1922KB) ( 532 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    A neighbor selection algorithm was proposed which was composed of sub-algorithms of peer selection and chunk selection.The peer selection algorithm assured that the peers could find the neighbors providing the video data at a high probability.The chunk selection algorithm helped peers choose the methods of downloading data,from which the data chunks could be used at a high availability.The experiment demonstrates that the algorithm can further decrease the server bandwidth costs and the refusal rate of peers' requisition,and improve the download rate of peers.

    Secure network coding scheme for scalable video streaming
    Xi-meng LIU,Guang-jun LIU,Jian-feng MA,Jin-bo XIONG
    2013, 34(5):  184-191.  doi:10.3969/j.issn.1000-436x.2013.05.021
    Asbtract ( 206 )   HTML ( 1)   PDF (1232KB) ( 369 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    With the purpose to achieve hierarchical security levels for scalable video streaming in heterogeneous net-works,random function was used to randomize parts of the video streaming in each layer.Network coding scheme was also used to resist known-plaintext attacks.Moreover,network encoder was studied.Ordered random linear network en-coder was designed for scalable video transmission.It could achieve scalability in security levels with few random opera-tions and reduce communication overhead.Analysis shows that the scheme could effectively increase the network throughput.

    Research on PDE-based adaptive anisotropic image registration
    Shu-jing JIANG,Bao-qin HEI,Jiu-xing ZHANG,Qian-nan LI
    2013, 34(5):  192-199.  doi:10.3969/j.issn.1000-436x.2013.05.022
    Asbtract ( 199 )   HTML ( 1)   PDF (1715KB) ( 422 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    A PDE-based adaptive anisotropic model for image registration was proposed to solve the problem that tradi-tional optical flow brings on the image blurring and details losing.The new model introduces adaptivity image registration,and defines anisotropic diffusion function with the ability of preserving image structure as the regu-larization term;the data term use a non-quadratic penalty function with the assumption in brightness constant to improve the robust of the model.The experimental results show that the model can efficiently protect the image structure and achieve accurate registration of the complex image like brain.

    ICFF: a cloud forensics framework under the IaaS model
    Ya-long XIE,Li-ping DING,Yu-qi LIN,Xiao-ke ZHAO
    2013, 34(5):  200-209.  doi:10.3969/j.issn.1000-436x.2013.05.023
    Asbtract ( 292 )   HTML ( 15)   PDF (680KB) ( 696 )   Knowledge map   
    Figures and Tables | References | Related Articles | Metrics

    Technical challenges of cloud forensics was summarized and a forensics framework under an infrastructure as a service(IaaS) cloud model called ICFF was proposed.Then,this framework on the open source IaaS cloud platform Eucalyptus was implemented.Finally,a test case to demonstrate the effectiveness of ICFF was designed.Experiments show that the framework can obtain evidence data in cloud platform effectively and efficiently.

Copyright Information
Authorized by: China Association for Science and Technology
Sponsored by: China Institute of Communications
Editor-in-Chief: Zhang Ping
Associate Editor-in-Chief:
Zhang Yanchuan, Ma Jianfeng, Yang Zhen, Shen Lianfeng, Tao Xiaofeng, Liu Hualu
Editorial Director: Wu Nada, Zhao Li
Address: F2, Beiyang Chenguang Building, Shunbatiao No.1 Courtyard, Fengtai District, Beijing, China
Post: 100079
Tel: 010-53933889、53878169、
53859522、010-53878236
Email: xuebao@ptpress.com.cn
Email: txxb@bjxintong.com.cn
ISSN 1000-436X
CN 11-2102/TN
Visited
Total visitors:
Visitors of today:
Now online: