本期目录

2007年 14卷 4期 刊出日期：2007-12-24



Wireless

On-demand data broadcast scheduling based on AHP and GRA methods in wireless broadcast/UMTS integrated systems

王慧;李春; 纪阳

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0001-06

摘要 ( 2348 ) PDF (224 KB)( 510 )

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The increasing demand for interactive mobile multimedia service is causing the integration of 3rd generation (3G) cellular systems and wireless broadcast systems. The key challenge is to support data dissemination with low response time, request drop rate, and the unfairness of request drop. This article proposes a novel scheduling algorithm called DAG (on-demand scheduling utilizing analytic hierarchy process (AHP) and grey relational analysis (GRA)), which takes multiple factors—waiting time, number of active requests, deadline—into consideration, and models the data scheduling process as a multiple factors’ decision-making and best option-selecting process. The proposed approach comprises two parts. The first part applies AHP to decide the relative weights of multiple decision factors according to user requests, while the second adopts GRA to rank the data item alternatives through the similarity between each option and the ideal option. Simulation results are presented to demonstrate that DAG performs well in the multiple criterions mentioned above.

Distributed localization using mobile beacons in wireless sensor networks

匡兴红;邵惠鹤

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0007-06

摘要 ( 2223 ) PDF (309 KB)( 490 )

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A new distributed node localization algorithm named mobile beacons–improved particle filter (MB-IPF) was proposed. In the algorithm, the mobile nodes equipped with globe position system (GPS) move around in the wireless sensor network (WSN) field based on the Gauss-Markov mobility model, and periodically broadcast the beacon messages. Each unknown node estimates its location in a fully distributed mode based on the received mobile beacons. The localization algorithm is based on the IPF and several refinements, including the proposed weighted centroid algorithm, the residual resampling algorithm, and the markov chain monte carlo (MCMC) method etc., which were also introduced for performance improvement. The simulation results show that our proposed algorithm is efficient for most applications.

Energy equalizing routing for fast data gathering in wireless sensor networks

郑杰，郭淑杰，屈玉贵，赵保华

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0013-09

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Energy saving and fast responding of data gathering are two crucial factors for the performance of wireless sensor networks. A dynamic tree based energy equalizing routing scheme (DTEER) was proposed to make an effort to gather data along with low energy consumption and low time delay. DTEER introduces a dynamic multi-hop route selecting scheme based on weight-value and height-value to form a dynamic tree and a mechanism similar to token passing to elect the root of the tree. DTEER can simply and rapidly organize all the nodes with low overhead and is robust enough to the topology changes. When compared with power-efficient gathering in sensor information systems (PEGASIS) and the hybrid, energy- efficient, distributed clustering approach (HEED), the simulation results show that DTEER achieves its intention of consuming less energy, equalizing the energy consumption of all the nodes, alleviating the data gathering delay, as well as extending the network lifetime perfectly.

Joint detection and combining schemes in MIMO-HARQ systems

谢刚;熊芳;刘元安

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0022-05

摘要 ( 2186 ) PDF (274 KB)( 461 )

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This article mainly investigates the combining schemes for hybrid automatic retransmission request (HARQ) protocols in multiple-input multiple-output (MIMO) wireless communication systems. A novel scheme, which joins MIMO detection and HARQ combining, called mid-combining, is presented in this article. Based on the position of HARQ combining, we classify the HARQ combining schemes into three types, named pre-combining, mid-combining, and post-combining. The simulation results show that mid- combining can increase the system throughput for all SNRs.

Handover with resource pre-allocation in the OFDMA systems

李明菊; 许宁; 王莹; 张平

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0027-05

摘要 ( 2631 ) PDF (249 KB)( 396 )

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This article proposed a new handover algorithm for beyond the third generation (B3G) systems with an orthogonal frequency division multiple access (OFDMA) downlink. In the proposed algorithm, handover mobile termination (MT) chooses a subchannel set in the candidate cells by a subchannel booking rule, based on the terminal speed and the subchannel’s channel state information (CSI). Moreover, the handover decision is made after analyzing if at least one candidate cell can reserve the subchannel set for the handover user. Simulation results show that the algorithm reduces the number of handovers and guarantees the quality of service (QoS) for the handover users. It yields better system performance in the OFDMA systems.

Ergodic channel capacity of the spatial correlated rayleigh MIMO channel

张会平;武平;刘爱军

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0032-04

摘要 ( 2496 ) PDF (239 KB)( 443 )

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The theoretical capacity of the spatial correlated Rayleigh multiple input multiple output (MIMO) channel is an important issue in MIMO technology. In this article, an ergodic channel capacity formula of the spatial correlated rayleigh MIMO channel is provided, which is deduced when two antennas exist at either the transmitter or the receiver. The multi-dimensional least-squares fit algorithm is employed to narrow the difference between the theoretical formula capacity and the practical capacity. Simulation results show that the theoretical capacity approaches the practical one closely.

Semiparametric theory based MIMO model and perfor- mance analysis

许方敏;许晓东; 张平

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0036-05

摘要 ( 2336 ) PDF (287 KB)( 407 )

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In this article, a new approach for modeling multi- input multi-output (MIMO) systems with unknown nonlinear interference is introduced. The semiparametric theory based MIMO model is established, and Kernel estimation is applied to combat the nonlinear interference. Furthermore, we derive MIMO capacity for these systems and explore the asymptotic properties of the new channel matrix via theoretical analysis. The simulation results show that the semiparametric theory based modeling and kernel estimation are valid to combat this kind of interference.

Inter-antenna and subblock shifting and inversion for peak- to-average power ratio reduction in MIMO-OFDM systems

王轶;陶小峰

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0041-05

摘要 ( 2231 ) PDF (308 KB)( 382 )

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In this article, an inter-antenna inter-subblock shifting and inversion (IASSI) scheme is proposed to reduce the peak-to-average power ratio (PAPR) in multi-input multi- output orthogonal frequency division multiplexing (MIMO- OFDM) systems. It exploits multiple antennas and subblocks to provide additional degrees of freedom to benefit the system. To reduce the implementation complexity of the proposed scheme, two simple suboptimal schemes are further presented based on the minimum current maximum criterion; one adopts sequential search and the other employs random binary grouping. The simulation results exhibit the effectiveness of these proposed schemes.

Analysis of the call blocking rate of two-hop-relay cellular system in the dead spots

鲁蔚锋;吴蒙

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0046-07

摘要 ( 2210 ) PDF (352 KB)( 391 )

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In a traditional cellular system, the call requests initiated by mobile stations (MSs) must be carried through a base station (BS) via the cellular interface, but when MSs are located in the dead spots, their call requests will be blocked because the MSs cannot communicate with the BS. It is considered to relay these blocked calls requested using Ad-hoc network, which will improve the performance of the system as a whole. This article first introduces a novel architecture of the two-hop-relay cellular system in the dead spots, and then analyzes and compares the call blocking rate of the traditional cellular and the two-hop-relay cellular system respectively under three different conditions. The first and second conditions are the traditional cellular system without and with taking account of the effect of the dead spots. The third condition is the two-hop-relay cellular system with taking account of the effect of the dead spots. Numerical analytical result shows that the two-hop-relay cellular system can obtain lower call blocking rate than the traditional cellular system when considering the effect of dead spots. Consequently, this novel architecture can resolve the problem of coverage limitation of a traditional cellular system effectively.

Artificial Intelligence

New families of p-ary sequences with low correlation and large linear span

佟鑫;温巧燕

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0053-04

摘要 ( 2165 ) PDF (284 KB)( 433 )

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This article presents a new family of p-ary sequences. The proposed sequences are proved to have not only low correlation property, but also large linear span and large family size. Furthermore, it shows that the new family of sequences contains Tang’s construction as a subset if m-sequences are excluded from both constructions.

How to signcrypt a message to designated group

马春波;敖珺;李建华

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0057-07

摘要 ( 2194 ) PDF (267 KB)( 376 )

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In an open network environment, the protection of group communication is a crucial problem. In this article, a novel broadcast group-oriented signcryption scheme is presented for group communication scenarios in distributed networks. Anyone in this scheme can signcrypt a message and distribute it to a designated group, and any member in the receiving group can unsigncrypt the ciphertext. The ciphertext and public key in the scheme are of constant size. In addition, this new scheme offers public verification of the ciphertext. This property is very important to the large-scale group communication since the gateway can filter the incorrect ciphertext and alleviate the receiver’s workload. Finally, a proof in the random oracle model is given to show that the scheme is secure against chosen ciphertext attack and existential forgery.

Multipurpose speech watermarking based on multistage vector quantization of linear prediction coefficients

陈宁;朱杰

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0064-06

摘要 ( 2311 ) PDF (287 KB)( 473 )

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To make speech watermarking achieve both copyright protection and integrity verification, a novel multipurpose speech watermarking algorithm based on the multistage vector quantization (MSVQ) of linear prediction coefficients (LPCs) is presented in this article. The property of natural speech that the vector quantization (VQ) indices of the LPCs amongst neigh- boring frames tend to be very similar is utilized to embed the robust watermark in the indices of the first-stage VQ (VQ1). Then, the semi-fragile watermark is embedded in the indices of the second-stage VQ (VQ2) with index constrained VQ encoding scheme. Both the robust watermark and the semi-fragile water- mark can be extracted without host speech. Simulation results verify the effectiveness of the proposed algorithm in terms of robustness and semi-fragility.

Grid trust based on pre-measure and two-level reputation

张琳;王汝传;王海艳

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0070-07

摘要 ( 2424 ) PDF (331 KB)( 392 )

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Security has been the focus of grid systems recently. As a kind of tool, grid security infrastructure (GSI) provides the authentication and authorization services and so on. These mechanisms mostly belong to the objective factors, which have not met the needs of security. As the subjective factor, trust model plays an important role in security field. A new two-level reputation trust architecture for grid is given to reduce the costs of system management largely, in which trust relationships amongst virtual organizations (VOs) are built on domain trust managers (DTMs) rather than resource nodes (RNs). Taking inter-domain trust propagation for example, trust model is improved by integrating global reputation and the subjective trust concept of each recommender into synthesizing final trust value. Moreover, before the grid starts to interact with the trustworthy entities, the pre-measure scheme is presented to filter distrustful entities further, which is based on accuracy and honesty. Experimental results indicate that the model can prevent from the malicious attacks better.

Information security assurance lifecycle research

谢成山; 许佳古月; 王理

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0077-05

摘要 ( 2274 ) PDF (169 KB)( 462 )

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This article proposes that problems of information security are mainly caused by the ineffective integration of people, operation, and technology, and not merely by the poor use of technology. Based on the information lifecycle, a model of the information security assurance lifecycle is presented. The crucial parts of the model are further discussed, with the information risk value and protect level, and the solution in each step of the lifecycle is presented with an ensured information risk level, in term of the integration of people, operation, and technology.

Network

Efficient delay based scheduling with fairness in multi-hop wireless mesh networks

王坤;彭木根;王文博

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0082-06

摘要 ( 2289 ) PDF (307 KB)( 386 )

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Some scheduling algorithms have been designed to improve the performance of multi-hop wireless mesh networks (WMNs) recently. However the end-to-end delay is seldom considered as the complexity of multi-hop topology and open wireless shared channel. This article proposes an efficient delay based scheduling algorithm with the concept of buffer-data- hops. Considering the demand satisfaction factor (DSF), the proposed algorithm can also achieve a good fairness performance. Moreover, with the interference-based network model, the scheduling algorithm can maximize the spatial reuse, compared to those graph-based scheduling algorithms. Detailed theoretical analysis shows that the algorithm can minimize the end-to-end delay and make a fair scheduling to all the links.

Dynamic access clustering selecting mechanism based on Markov decision process for MANET

王道远;田辉

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0088-05

摘要 ( 2255 ) PDF (209 KB)( 410 )

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Clustering is an important method in the mobile Ad-hoc network (MANET). As a result of their mobility, the cluster selection is inevitable for the mobile nodes during their roaming between the different clusters. In this study, based on the analysis of the cluster-selecting problem in the environment containing multiple clusters, which are overlaying and intercrossing, a novel dynamic selecting mechanism is proposed to resolve the dynamic selection optimization of roaming between the different clusters in MANET. This selecting mechanism is also based on the consideration of the stability of communication system, the communicating bandwidth, and the effect of cluster selecting on the communication and also in accordance with the Markov decision-making model.

Engineering costs proxy models for China rural access network and its application

傅云谨;周黄嘉;忻展红;孙红斌

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0093-07

摘要 ( 2111 ) PDF (289 KB)( 422 )

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The article builds three engineering rural access network models that describe the structure of network elements and their relative engineering parameters for cable access、synchronous code division multiple access (SCDMA), and very small aperture terminal (VSAT) access technologies in the rural areas of China. Of the three access technologies, cable access and SCDMA access are the most popular access technologies. Besides, there still exist some remote special areas such as western mountain areas, whose natural environment is so bad that VSAT becomes the unique economical access way. Fully considering rural areas’ geographical environments’ impact, the article introduces geographical revised factor (GRF) to the models. By substituting the network data from the operators into the models, the article obtains the integrated networking values and does further researches on different access networks.

B3G

Improved RB-HARQ scheme based on structured LDPC codes

王文君;林粤伟;闫渊

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0100-04

摘要 ( 2605 ) PDF (139 KB)( 745 )

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Reliability-based hybrid automatic repeat request (ARQ) (RB-HARQ) is a recently introduced approach to incremental-redundancy ARQ. In RB-HARQ scheme, the bits that are to be retransmitted are adaptively selected at the receiver based on the estimated bit reliability. It could result in significant performance gain but requires huge overhead in the feedback channel. In this study, an improved RB-HARQ scheme (IRB-HARQ) for structured low-density parity-check codes is proposed, which simplifies the comparison operations needed to search the bits to be retransmitted and outperforms the RB-HARQ scheme in consideration of the bit transmission power for the requesting messages on the feedback link. Simulation results show that the IRB-HARQ scheme is more efficient and practical than the RB-HARQ scheme.

Microelectronics and solid state electronics

Low-power clock-less hardware implementation of the rijndael S-box for wireless sensor networks

曾永红;邹雪城;刘政林;雷鉴铭

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0104-06

摘要 ( 2532 ) PDF (399 KB)( 465 )

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The recent development of microelectronics techniques and advances in wireless communications have made it feasible to design low-cost, low-power, multifunctional and intelligent sensor nodes for wireless sensor networks (WSN). The design challenges for an efficient WSN mainly lie in two issues: power and security. The Rijindael algorithm is a candidate algorithm for encrypting data in WSN. The SubByte (S-box) transformation is the main building block of the Rijindael algorithm. It dominates the hardware complexity and power consumption of the Rijindael cryptographic engine. This article proposes a clock-less hardware implementation of the S-box. In this S-box, 1) The composite field arithmetic in GF((24))2 was used to implement the compact datapath circuit; 2) A high-efficiency latch controller was attained by utilizing the four-phase micropipeline. The presented hardware circuit is an application specific integrated circuit (ASIC) on 0.25 μm complementary mental oxide semiconductor (CMOS) process using three metal layers. The layout simulation results show that the proposed S-box offers low-power consumption and high speed with moderate area penalty. This study also proves that the clock-less design methodology can implement high- performance cryptographic intellectual property (IP) core for the wireless sensor node chips.

Image recognization

Realistic face modeling based on multiple deformations

龚勋;王国胤

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0110-08

摘要 ( 2078 ) PDF (620 KB)( 493 )

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On the basis of the assumption that the human face belongs to a linear class, a multiple-deformation model is proposed to recover face shape from a few points on a single 2D image. Compared to the conventional methods, this study has the following advantages. First, the proposed modified 3D sparse deforming model is a noniterative approach that can compute global translation efficiently and accurately. Subsequently, the overfitting problem can be alleviated based on the proposed multiple deformation model. Finally, by keeping the main features, the texture generated is realistic. The comparison results show that this novel method outperforms the existing methods by using ground truth data and that realistic 3D faces can be recovered efficiently from a single photograph.

Electromagnetic theory

Reconstruction of cylindrically layered media using an iterative algorithm with a stable solution

成际镇;牛作元;程崇虎

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0118-04

摘要 ( 2066 ) PDF (242 KB)( 430 )

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The reconstruction of cylindrically layered media is investigated in this article. The inverse problem is modeled using a source-type integral equation with a series of cylindrical waves as incidences, and a conventional Born iterative procedure is modified for solving the integral equation. In the modified iterative procedure, a conventional single-point approximation for the calculation of the field inside media is replaced by a multi-points approximation to improve the numerical stability of its solution. Numerical simulations for different permittivity distributions are demon- strated in terms of artificial scattering data with the procedure. The result shows that the procedure enjoys both accuracy and stability in the numerical computation.

UWB

Frequency notched wide slot antenna for UWB/2.4 GHz WLAN applications

吕文俊; 朱洪波

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0122-04

摘要 ( 2261 ) PDF (424 KB)( 471 )

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A compact frequency notched microstrip slot antenna for ultra-wideband (UWB) /2.4 GHz-band wireless local area network (WLAN) applications is proposed. The antenna is similar to a conventional microstrip slot antenna; however, by introducing a cross wide slot and a meandered-slotted stub, both compact size and frequency notched function can be achieved. It has been studied both numerically and experi- mentally for its impedance bandwidth, surface current distribution, radiation patterns, and gain. As will be seen, an operation bandwidth of over 4.6:1 ranging from 2.39 to 11.25 GHz for return loss lower than having a frequency notched band ranging from 4.75 to 5.85 GHz has been achieved, and good radiation performance over the entire frequency range has also been achieved.

Signal processing

Discriminative tonal feature extraction method in mandarin speech recognition

黄浩; 朱杰

中国邮电高校学报(英文), 2007, 14 (4). doi： 1005-8885 (2007) 04-0126-05

摘要 ( 2111 ) PDF (289 KB)( 367 )

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To utilize the supra-segmental nature of Mandarin tones, this article proposes a feature extraction method for hidden markov model (HMM) based tone modeling. The method uses linear transforms to project F0 (fundamental frequency) features of neighboring syllables as compensations, and adds them to the original F0 features of the current syllable. The transforms are discriminatively trained by using an objective function termed as “minimum tone error”, which is a smooth approximation of tone recognition accuracy. Experiments show that the new tonal features achieve 3.82% tone recognition rate improvement, compared with the baseline, using maximum likelihood trained HMM on the normal F0 features. Further experiments show that discriminative HMM training on the new features is 8.78% better than the baseline.