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    25 August 2010, Volume 31 Issue 8
    Academic paper
    Anti-jamming performance of multi-tone DSSS in the presence of tone and partial band interference
    Xin HE,Xiao-lin ZHANG
    2010, 31(8):  1-87.  doi:1000-436X(2010)08-0075-09
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    Due to the substantial spectral overlap of non-orthogonal subcarriers in multi-tone direct sequence spread spectrum (MT), the affect caused by narrowband jamming on each subcarrier simultaneously was nduced to different extent rather than the sum up of several identical cases of jammed single-carrier DSSS.Through the quantitative analysis of the above case, the decision statistics and averaged bit error rate of correlative detected single/multiuser MT system with tone and partial band jamming were calculated analytically, which was verified through the numerical simulations.The results show that, under the condition of equivalent receiver complexity and same bandwidth efficiency MT has much larger processing gain compared with single-carrier DSSS and orthogonal multicarrier DSSS, which is capable of effectively suppresses the internal inter-subcarrier interference, while has good anti-jamming capability against narrowband and multiuser interference.

    Least square-based vehicle position estimation algorithm
    Xin PENG,Ren-fa LI,Liu YANG,Liang-jiao LIU
    2010, 31(8):  9-15.  doi:1000-436X(2010)08-0009-07
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    A vehicle position estimation algorithm base on least square optimization was prposed.Firstly the algorithm deduced the convex constraint condition which the distance matrix had to conform within a short time interval.Then, the least square method was employed to estimate the vehicles’relative position.Finally, the local maps were merged into the global map.Simulation results demonstrate that the algorithm can ieve preferable estimation accuracy, and meet the real time constraint in vehicular networks.

    Distributed Voronoi coverage algorithm in wireless sensor networks
    Peng-fei XU,Zhi-gang CHEN,Xiao-heng DENG
    2010, 31(8):  16-25.  doi:1000-436X(2010)08-0016-10
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    On the hypothesis conditions that wireless sensor networks only covered partial target region and the communication radius was no less than twice of the sensing radius, a coverage-preserved and connected distributed Voronoi coverage algorithm was presented.Firstly, a method of detecting coverage redundancy sensors based on the local Voronoi regions was proposed, whose computational complexity was unconcerned with the density of sensors.Then, an energy-prior self-scheduling strategy based on local Voronoi neighbors was proposed, where those sensors that were communication neighbors but not local Voronoi neighbors could synchronously execute self-scheduling, which improved the astringency of distributed scheduling.The simulation results show that the average number and coverage-degree of active sensors produced by the proposed algorithm are close to the centralized algorithm and smaller than the general distributed algorithm, while the proposed algorithm has more advantages in terms of active sensors’ average energy, scheduling astringency and runtime.

    Improvement of equivalent power consumption coding secure against power analysis attacks
    Zhen WU,Yun CHEN,Min WANG,Jun CHEN
    2010, 31(8):  26-31.  doi:1000-436X(2010)08-0026-05
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    Equivalent power consumption coding algorithm not only could improve algorithm efficiency, but also could be against the power analysis attacks.But it had weak in all-zero exponential segment because of a defect of pseudo-operation design.So a new pseudo-operation was proposed to improve the algorithm’s security.And a rapid implementation using Montgomery algorithm was presented too.It could accelerate the operation with no-lower safety.The research’s validity is proved in the real power testing platform.

    Novel self-organized resource management mechanism for large-scale Grid over OBS networks
    Bing ZUO,Lei LIU,Jian WU,Jin-tong LIN
    2010, 31(8):  32-39.  doi:1000-436X(2010)08-0031-08
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    In order to avoid the problems of client/server (C/S)-based resource management scheme in grid over optical burst switching (OBS) networking, an improved self-organized resource management mechanism based on the peer-to-peer (P2P) technology and the previous works was proposed.By utilizing the P2P technology and special description of resources, the proposed mechanism could achieve distributed resource information storage and fast resource discovery capability.Simulation results show that the proposed mechanism can not only address the issues of poor scalability and fault-tolerance introduced by traditional C/S-based schemes, but also reduce the time for resource discovery.Therefore, it is more suitable for future large-scale consumer-oriented optical grid applications.

    Research on the multiple subarray-pairs interferometric algorithm used in high resolution multibeam bathymetric system
    Tian ZHOU,Shan LI,Hai-sen1 LI,Xiao LIU
    2010, 31(8):  40-45.  doi:1000-436X(2010)08-0039-06
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    An optimized subarray configuration was analyzed theoretically for the performance enhancement of interferometric algorithm used in multibeam bathymetric system, and the relationship between phase ambiguity existed in interferometric algorithm and subarray configuration was deduced theoretically.On the basis, a new multiple subarray-pairs interferometric algorithm was proposed, which not only solved the difficulties of phase ambiguity unwrapping highly efficient, but improved the resolution and coverage performance of bathymetric estimation of system.The processing results of experiment data prove the efficiency, practicality and superiority of the new algorithm.

    Effective cooperative scheme based on relay selection
    Fei YU,Lv-xi YANG
    2010, 31(8):  46-53.  doi:1000-436X(2010)08-0045-09
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    Based on the capacity of multi-access channel, a relay selection algorithm was proposed.It was proposed that:relays were selected according to the eigenvalue decomposition of the equivalent relay-destination channel, and the beamforming vectors were designed in a distributed manner.It could be seen that joint processing and information transmission between multiple relays were avoided, which could reduce system complexity.Simulation results show that the system proposed can achieve better bit error rate (BER) comparing to the one with multi-relay parallel transmission.

    Performance of XFAST in the presence of code Doppler
    Xiao-mei TANG,Shao-wei YONG,Fei-xue WANG
    2010, 31(8):  54-59.  doi:1000-436X(2010)08-0054-06
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    The probability of detection and false alarm in XFAST (extended replica folding acquisition search technique) were introduced in the condition of code Doppler and deterioration of noise caused by replica folding.The simulation results show that the model is correct, the equal signal to noise error is less than 0.5dB.The research is the academic base of XFAST parameter optimization and performance.When the extended replica folding number equal to 1, the model can be used to analyse other acquisition algorithm.

    Synthesis of arbitrary current mode filter
    Zhi-jun LI,Chun-hua WANG,Rong LIU
    2010, 31(8):  60-65.  doi:1000-436X(2010)08-0060-06
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    A new general analytical synthesis method for arbitrary current mode filter was presented.The method was based on the analytical decomposition of a complicated high-order transfer function into lossless integrators and cur-n n rent proportional blocks by a succession of innovative algebra process.The filter structure based on MCCIIs was proposed with the following advantages: 1) it can be used not only for arbitrary-order filters,but also for different filter types such as Butterworth, Chebyshev and Elliptic; 2) the circuit structure proposed only contains (2 +1) active elements,n (2 +1) resistors and capacitors; 3) all the elements are grounded, so it is convenient to be integrated; 4) the differentn n filter functions such as high-pass, low-pass, band-pass, band-reject and all-pass can be obtained when it act as a Butterworth filter.A third-order elliptic low-pass filter and a sixth-order Butterworth universal filter were employed to demonstrate the realization scheme.The validity of the proposed structure was verified through PSPICE simulations.

    Multicast resource allocation scheme considering source-coding characteristic in OFDM systems
    Wen-jun XU,Zhi-qiang HE,Kai NIU,Jia-ru LIN,Wei-ling WU
    2010, 31(8):  66-74.  doi:1000-436X(2010)08-0066-09
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    Aiming to solve the problem that unicast or conventional multicast was incapable of make full use of the opening for wireless propagation in orthogonal frequency division multiplexing(OFDM) systems, a resource allocation scheme involving several multicast groups was proposed to maintain proportional fairness among groups.The proposed scheme consisted of subcarrier assignment algorithm and power allocation algorithm.The former was achieved by modifying the existing unicast subcarrier assignment algor m, whilst optimal power allocation on condition that subcarrier assignment was determined was reached by the latter based on theoretically derived non-linear equations.Simulation results show that the proposed scheme can ensure perfect fairness among different multicast groups, and remarkably outperforms conventional multicast in terms of rate-sum capacity.Combined with the low complexity, it is suitable for the application to voice/video multicast in actual wireless systems.

    Design of single-symbol-decodable QOSTBC with full diversity based on pre-processing
    Wen-jing CHENG,Wei LIU,Ding DING,Ji-bo WEI
    2010, 31(8):  84-90.  doi:1000-436X(2010)08-0084-07
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    The method of pre-processing was applied to G-QOSTBC in order to reduce the complexity of decoding, which was single-symbol-decodable.Furthermore, an improved transmit strategy proposed to achieve full diversity as well as maximum coding gain by constellation rotating and symbol interleaving.Simulation results show that the proposed code remarkably decreases the decoding complexity of G-QOSTBC while keeping the similar performance.In addition, the proposed code has the same bit-error-rate (BER) performance as coordinate interleaved orthogonal design (CIOD), but with a lower peak-to-average ratio (PAR).

    DOA estimation based on JADE algorithm
    Jia ZHAO,Jing-shu YANG,Jia-bao JIN
    2010, 31(8):  91-97.  doi:1000-436X(2010)08-0091-07
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    A novel method based on JADE algorithm was proposed to estimate the DOA in multi-path environment.With no priori assumptions about the structure of the steering vector, the array manifold was estimated by the JADE algorithm.As the steering vector in this array manifold was a linear combination of multiple complex sinusoids, the DOA estimation could be realized by the spectral analysis method.The simulation results show that the new method can estimate the DOA of two signals in the same direction.And compared with Toeplitz approximation method (TAM), in multi-path environment the proposed method is steady, and is workable when the number of signals exceeds the number of sensors.

    engineering report
    Direct anonymous authentication scheme for wireless networks under trusted computing
    Li YANG,Jian-feng MA,Qing-qi PEI,Zhuo MA
    2010, 31(8):  98-104.  doi:1000-436X(2010)08-0098-07
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    Based on direct anonymous attestation of trusted computing, a wireless anonymous authentication scheme was proposed, the platform of the mobile node was verified by the foreign network agent and the identity of mobile node user was authenticated by the home network agent and the foreign network agent together.By using of temporary identi-ties and one time secret keys, identity anonymity and separation property are achieved.The analysis shows that the scheme is secure, reliable, and with higher performance.

    RTP stream transferring scheme with load balancing and delay optimization in PoC
    Hai-peng LIU,Jian-xin LIAO,Xiao-min ZHU
    2010, 31(8):  105-113.  doi:1000-436X(2010)08-0105-09
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    After modeling the RTP(real-time transport protocol) stream transferring scheme proposed by OMA (open mobile alliance) for PoC (push to talk over cellular) server, an improved scheme was presented.Under the w scheme media traffic through CS(controlling server) could be reduced largely and the transferring delay of RTP package could also be shortened obviously by enhancing PS(participating server) controlling capabilities and importing distri-buted-controlling ideas into PoC system.Analyzing and simulation results show that the new scheme always performs better than the original one in fields of load balancing and media transferring delay optimization.

    Low complexity uplink multiuser MIMO detecting algorithm
    Yong-qiang HEI,Xiao-hui LI,Ke-chu YI,Hong YANG
    2010, 31(8):  114-120.  doi:1000-436X(2010)08-0114-07
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    Aiming at the uplink multiuser MIMO system, a new space-time detecting algorithm was proposed, in which a linear recombination strategy was imposed on the received signal first, and then the matched filter vectors orthogonal to each users’ interference sets were used to eliminate the interference among users.Finally the signal of each user was linearly space-time decoded by means of the orthogonal equivalent channel.The design of the algorithm under imperfect channel scenario was also provided.Theory analysis and simulation results reveal that the proposed algorithm has the advantages of low complexity and good robustness, and is superior to other detecting algorithms.

    essay
    On the transmission time of fountain code based parallel relay network
    Dan WU,Ya-fei TIAN,Chen-yang YANG
    2010, 31(8):  121-126.  doi:1000-436X(2010)08-0121-06
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    In order to reduce the complexity of transmission protocols and the number of feedback links, fountain code was applied to the multi-stage parallel relay network for open-loop error control.The fountain code based network transmission scheme and frame format were presented.The transmission time for both the fountain code based scheme and the conventional ARQ based scheme was analyzed and compared.Results show that the total time consumed under fountain code based scheme can be significantly reduced compared to the ARQ based scheme.With the increase of relay numbers, the advantage of the fountain code based scheme is more evident.

    Distance-assistant node coverage identification model for wireless sensor networks
    Gao-juan FAN,Li-juan SUN,Ru-chuan WANG,Hai-ping HUANG
    2010, 31(8):  127-133.  doi:1000-436X(2010)08-0127-07
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    A distance-assistant node coverage identification model was proposed which adopts distance information between the node and its neighbors to identify nodes coverage without using any location information.Theory analysis and simulation results are presented to evaluate the proposed DANCI model.It is shown that in randomly deployed sensor networks, the maximum error between DANCI model and location information-aware strategy is 6.396 0%, and the nodes coverage accuracy improves significantly compared to neighbor number-based scheme and nearest neighbor-based scheme.

    Architecture and key technology of public computing communication network
    Xiao-yu TONG,Yun-yong ZHANG,Yuan-shun DAI
    2010, 31(8):  134-140.  doi:1000-436X(2010)08-0134-07
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    The development processes of public communication network and computing were reviewed.Then a new concept of public computing communication network was proposed and analyzed in detail.The inevitable evolution of public communication network into PCCN was elaborated.The architecture, entities and key technologies of PCCN were discussed in detail.

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
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