Current Issue

25 April 2005, Volume 26 Issue 4

Previous Issue    Next Issue

Technical Report

Framework ＆ highlights of MSR system（ITU-T X.87/Y.1324）

Shao-hua YU,Ming CAI

2005, 26(4):  1-72.  doi:1000-436X(2005)04-0063-07

Asbtract ( 0 )   HTML ( 2)   PDF (477KB) ( 173 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

The convergent transport of voice/data/video networks was the major scope of this paper. The multi-services transport and switch, protocol elements, topologies, transmission framework, structure of system architecture and generic frame format of MSR were studied by means of resilient packet ring (RPR) and its multi-services transport according to carrier-class demands for multiple services of optical metropolitan area networks. By comparison with RPR.MSR is an effective transport solution of adding and dropping multiple voice/data/video services, tributary multicast, protection and performance monitoring. MSR has lower cost and is an effective way of packet based multi-services transport and renting, it is needed by carrier if they has voice/data/video tributary services for rent at the same network platform.

academic paper

Performance analysis of ML estimation method of OFDM integer frequency offset

Chen CHEN,Jian-dong LI,Lin-jing ZHAO

2005, 26(4):  7-13.  doi:1000-436X(2005)04-0007-07

Asbtract ( 0 )   HTML ( 2)   PDF (804KB) ( 95 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

A novel method for integer frequency offset estimation of OFDM systems was derived, which was based on maximum likelihood (ML) technique. The mean and variance of the proposed and conventional method were discussed, and the probability of error estimation was compared between the two methods. The computer simulation results are in good agreement with the analytical study.

Decision directed SNR estimation algorithm combining with forward error correction

Hua XU,Hui ZHENG

2005, 26(4):  14-18.  doi:1000-436X(2005)04-0014-05

Asbtract ( 0 )   HTML ( 2)   PDF (487KB) ( 127 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

A decision-directed (DD) signal-noise-ratio(SNR) estimation algorithm for general MPSK signals was derived based on maximum-likelihood (ML) principle, and a scheme combining DD SNR estimation algorithm with forward error correction (FEC) was also developed. The result of analysis and simulation shows that the performance of new scheme is not only much better than that of DD algorithms but also prior to that of the algorithms presented recently.

Estimating the mutual coupling coefficient of arrays

Huo-tao GAO,Yong-xu LI,Xia ZHENG

2005, 26(4):  19-23.  doi:1000-436X(2005)04-0019-05

Asbtract ( 0 )   HTML ( 2)   PDF (500KB) ( 535 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

For the arrays of high frequency ground wave radar, a method with two signals to estimate the mutual coupling coefficient of arrays were brought out. which was based on the principle of signal subspace and utilizing the simulated annealing algorithm. A great deal of compute experiment proves the efficacy of this method.

Dynamic time-driven packet sampling technique

Wen-yu GAO,Song-qiao CHEN,Jian-xin WANG

2005, 26(4):  24-29.  doi:1000-436X(2005)04-0024-06

Asbtract ( 0 )   HTML ( 2)   PDF (986KB) ( 92 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

Proposed a dynamic time-driven packet sampling technique. This dynamic packet sampling could vary sampling degree with the change of network traffic, thus guarantee the error rate under a given level. In this way, high accuracy could be got at a low cost of network measurement. Moreover, this packet sampling technique was nearly as simple as “1 out of N”, theoretic analysis and experimental study were given. Experiment results show that this technique achieves design object. The idea of dynamic changing measurement scheme according to network state can be widely used in network measurement.

Novel alternate routing algorithm in multi-fiber WDM networks

Jun-feng QIAO,San-yang LIU,Xiao-gang QI

2005, 26(4):  30-33.  doi:1000-436X(2005)04-0030-04

Asbtract ( 57 )   HTML ( 2)   PDF (377KB) ( 367 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

Based on the conventional method named least loaded routing (LLR), the routing problem in wavelength division multiplexing (WDM) optical networks was discussed, and a novel algorithm called least loaded-hop routing (LLHR) scheme was proposed for multi-fiber networks, which takes into account both link load and route hop. The effect of network load and number of fibers and alternate routings on the performance of the algorithm was described. Simulation results show that the algorithm can significantly reduce blocking probability and improve network performance compared with LLR.

Multimodal images registration based on bandwidth matching

Xuan YANG,Ji-hong PEI,Wei-xin XIE

2005, 26(4):  34-37.  doi:1000-436X(2005)04-0034-04

Asbtract ( 57 )   HTML ( 2)   PDF (1338KB) ( 215 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

A novel registration method using mutual information based on smoothed image whose bandwidth was modified adaptively was proposed. It substitutes smoothing values for gray values in images and can avoid great change of joint probability distribution and has less local maxima. Theory analysis and experiments show that our method is effective and feasible to do multimodal image registration.

Building efficient multi-group signature schemes based on ACJT group signature schemes

Xin LIU,Qiu-liang XU,Jiu-qing SHANG

2005, 26(4):  38-44.  doi:1000-436X(2005)04-0038-07

Asbtract ( 51 )   HTML ( 3)   PDF (1512KB) ( 89 )   Knowledge map   

References | Related Articles | Metrics

In the previous multi-group signature scheme of G.Ateniese and G.Tsudik's, the main disadvantage was the use of the inefficient signature of knowledge protocol to prove the equality of two double discrete logarithms. To over come this shortage, two improved multi-group signature schemes were made in this paper, building on more efficient signature of knowledge protocols. The security of the new schemes was analyzed quite sufficiently in the random oracle. Moreover, the efficiency of the new schemes was compared with the original scheme using specific parameters. Additionally, an improved sub-group signature scheme of G.Ateniese and G.Tsudik's was also proposed. It can be proved that all the proposed schemes possess better security, efficiency and practicality.

Performance of space-time coding and optimized multiband complex wavelet based MC-CDMA system

Xiang-bin YU,Guang-guo BI

2005, 26(4):  45-51.  doi:1000-436X(2005)04-0045-07

Asbtract ( 56 )   HTML ( 2)   PDF (1159KB) ( 76 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

A novel MC-CDMA system based on optimized multiband complex wavelet and space-time coding was proposed, and the system bit error rate (BER) performance was investigated in Rayleigh fading channel. Theoretical analysis and simulation results show that the proposed system outperforms conventional MC-CDMA system, and it has comparative superiority to the conventional MC-CDMA with cyclic prefix (CP). Moreover, the system can overcome the decrease of spectrum efficiency and energy of conventional MC-CDMA due to inserting CP. Especially, the application of space-time coding technique significantly improves system ability to combat multi-path interference and multi-access interference.

A new distributed auction protocol

Man-chun CAI,chun-guang MA,Yi-xian YANG,Zheng-ming HU

2005, 26(4):  52-55.  doi:1000-436X(2005)04-0052-04

Asbtract ( 49 )   HTML ( 2)   PDF (886KB) ( 77 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

Based on the Schnorr identification protocol, verifiable secret sharing scheme, hash chain, a new sealed-bid auction protocol suitable for distributed environment was designed. Fairness and security property was provided by the auction, and non-repudiation and anonymity of the bidders was guaranteed by the auction. Furthermore it is implemented in the flexible way such as first-price and second-price, etc.

Space-time multiuser detection for MC-CDMA system based on improving generalized Steiner estimator

Bing HU,Ping-an LI,Bian-zhang YU

2005, 26(4):  56-62.  doi:1000-436X(2005)04-0056-07

Asbtract ( 41 )   HTML ( 2)   PDF (1219KB) ( 214 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

The space-time channel estimation and multiuser detection algorithm for the uplink of multicarrier CDMA (MC-CDMA) system in frequency selective Rayleigh fading channel were investigated. Considering that the fading coefficients corresponding to subcarriers were discrete Fourier transform of channel impulse response, we performed joint channel estimation for all users by inserting a midamble into two data blocks. The initial estimation of array antenna channel impulse response was first made according to the generalized Steiner estimator (GSE). Then a simple efficient cross-correlation direction-of-arrival (CCDOA) estimation algorithm for uniform linear array was presented to improve the estimation of array antenna channel impulse response. We reduced the noise in channel response from the view of space. After estimating the space-time channel parameter of all users, maximum ratio combining (MRC), decorrelating detection and minimum mean square error (MMSE) detection were constructed to perform signal detection. Simulation results show that the improved channel estimation algorithm based on CCDOA leads to a significant system performance improvement compared with the GSE.

Technical Report

Research on intrusion scenarios building based on multiple hypothesis tracking

Hui LI,Qing-hua ZHENG,Chong-zhao HAN,Xiao-hong GUAN

2005, 26(4):  70-78.  doi:1000-436X(2005)04-0070-10

Asbtract ( 39 )   HTML ( 3)   PDF (1236KB) ( 140 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

A fuzzy multiple hypothesis intrusion scenarios building algorithm was proposed based on multiple hypothesis tracking(MHT)theory which originated from information fusion. The algorithm could automatically analyze and organize alarms produced by intrusion detection systems to form credible attack segments and finally generate intrusion scenarios. The whole process can be divided into three steps, which were hypothesis generation, fuzzy hypothesis assessment and hypothesis management. Experiments on the DARPA2000 IDS test dataset show that the algorithm is effective and efficient.

Research on optimum interference suppression technique for spread spectrum systems: blind adaptive algorithm and parallel plementation

Lin LI,Wen-hui ZHOU,Shu-sen TAN,Er-yang ZHANG

2005, 26(4):  80-87.  doi:1000-436X(2005)04-0080-08

Asbtract ( 37 )   HTML ( 3)   PDF (1231KB) ( 597 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

In order to solve the problem of the dynamic interference suppression for spread spectrum systems, the recursive least squares(RLS)adaptive versions of the minimum mean square error (MMSE) criterion, and the blind recursive least squares (BRLS) adaptive versions of the constrained minimum mean output energy (MMOE) criterion were analyzed. The QR decomposition could overcome three major problems associated with the two adaptive algorithms, that is, numerical instability, computational complexity and difficult for parallel implementation. Then, the matters in the transition from the QR decomposition-based BRLS (QR-BRLS) to the QR decomposition-based RLS (QR-RLS) and vice versa were discussed. The systolic arrays for parallel implementation of the QR-RLS and the QR-BRLS adaptive interference suppression algorithms were also proposed. The theoretic analyses and the emulator results all indicate that the cooperation of the two algorithms can preferably resolve the dynamic interference suppression.

Study of network flow timeout strategy

Ming-zhong ZHOU,Jian GONG,Wei DING

2005, 26(4):  88-93.  doi:1000-436X(2005)04-0088-06

Asbtract ( 32 )   HTML ( 4)   PDF (612KB) ( 311 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

Firstly discussed the state-of-art of flow timeout strategies, and pointed out where they were applicable and their shortcomings. Presented a two-level self-adaptive timeout (TSAT) strategy which handles flows with different timeout strategy according to its feature. This method could improve the performances of network measurement and the efficiency of the resource usage of measurement systems. Some experiments were employed to show the rationality of TSAT strategy. Then the fitness area of strategy was anatomized as well.

Research on Turbo codes with short frame interleaver in fading channel

Ji LUO,Xi-lin ZHANG,Dong-feng YUAN

2005, 26(4):  94-98.  doi:1000-436X(2005)04-0094-05

Asbtract ( 31 )   HTML ( 2)   PDF (707KB) ( 241 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

High BER performance could be obtained by employing Turbo codes as channel coding scheme, whereas the design of interleaver was the key factor which influenced the performance of Turbo codes. A design scheme of short frame interleaver based on the study of code weight was proposed with the notion of sparse matrix by modifying S random interleaver. The performance of Turbo code with this short frame interleaver is improved by decreasing the number of low weight codewords.

Wireless channel playback modeling and its applications

Pei-gang JIANG,Shao-bo WANG,-jia LIHua

2005, 26(4):  99-104.  doi:1000-436X(2005)04-0099-06

Asbtract ( 94 )   HTML ( 8)   PDF (1191KB) ( 427 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

A deterministic wireless channel modeling method - playback channel modeling and its applications was presented. The general method of playback channel modeling was introduced and the requirement on the wireless channel measurement was analyzed briefly. The method and steps of processing practical measurement results for forming the playback model was described in detail. Finally an application example of the playback model in WCDMA physical layer design and optimization was presented. Through wideband high-speed real-time wireless channel measurement and post-processing, the time-variant wireless channel impulse response with high SNR can be obtained based on which the wireless playback channel model is able to duplicate exactly the practical wireless channel propagation characteristics.

Framework of workflow-based telecom enterprise application integration

Ya-hua CHEN,Shi-lin WU

2005, 26(4):  105-111.  doi:1000-436X(2005)04-0105-07

Asbtract ( 24 )   HTML ( 2)   PDF (481KB) ( 433 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

A workflow-based dynamic enterprise application integration (EAI) facilitates application reusability and flexible business process re-engineering. The EAI supported dynamic interoperation between heterogeneous workflow systems. To this end, based on subflow task model and multi-tiered dynamic state transition model, four major components were defined: the workflow engine, adapter,service interface repositories (SIRs), and XML messages. It gave a case about the process of a telephone order management, it shows the framework is feasible.

Study on CAMEL2-based SCP overload control

Yu-long WANG,Jian-xin LIAO

2005, 26(4):  112-116.  doi:1000-436X(2005)04-0112-05

Asbtract ( 25 )   HTML ( 2)   PDF (622KB) ( 119 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

A CAMEL2-based SCP overload control model was designed. An adaptive window control algorithm was proposed. This algorithm has stronger robustness than Callgap and Percent algorithms. Finally, the result of simulations prove the algorithm's effectiveness and fairness.

Short essay

Different utility based rate and power assigning algorithm for integrated services CDMA systems

Cai-xia LIU,Dong-nian CHENG,Ding-jiu YU,Yu-bo TAN,Jiang-xing WU

2005, 26(4):  117-121.  doi:1000-436X(2005)04-0117-05

Asbtract ( 51 )   HTML ( 2)   PDF (699KB) ( 106 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

A different utility based rate and power assigning algorithm was proposed for integrated services CDMA systems, which adopted step function as the voice users' utility function, adopted the function with the independent variable being rate as the data users' utility function and used the power price being the non-decreasing function of system load to control the power cost of the systems. The utility functions used not only could provide the higher priority to voice users, also could satisfy the different priority requirement of different kinds of data users by choosing different function parameters. Performance analysis indicates the algorithm can save the system power cost and increase the system capacity.

Expanding DES key space method based on chaotic maps

Li-yuan SHENG,Qing ZHANG,Ke-hui SUN,Wen-guang WANG

2005, 26(4):  122-124.  doi:1000-436X(2005)04-0122-03

Asbtract ( 51 )   HTML ( 7)   PDF (439KB) ( 268 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

The key space of DES is too small to prevent exhaust attacks. An expanding key space method was proposed, which was based on 3 principles of the Shannon's idea “one-time pad”, “infinite key space” and a chaotic system could make out of a determinate random number generator. And considering the security aspect of algorithm, 5 essential properties of an ideal chaotic system were proposed. In tests, a new transformed DES algorithm was constructed, in which DES was used as a basic algorithm, Logistic map as a random number generator to generate a key block sequence. Thus, the key space of DES increases from 256 to 2100. This method was fairly good in successfully solving the problem of expanding DES key space. The tests also show that the expanding key space method is easily implemented technically.

Security analysis of routing protocol for MANET based on BAN logic

Ying-long WANG,Ji-zhi WANG,Mei-qin WANG

2005, 26(4):  125-129.  doi:1000-436X(2005)04-0125-05

Asbtract ( 23 )   HTML ( 5)   PDF (451KB) ( 369 )   Knowledge map   

References | Related Articles | Metrics

The routing protocol for MANET uses cryptographic technology to heighten its security, which makes it possible to use formal method. Considered the property of routing protocol for MANET, the security is analyzed based on BAN logic. The condition that the protocol should be met is given. The formalization of the protocol is described and the method is presented. Taken example of SADSR, the security of routing protocol is analyzed by using the method, which proves the method is valid.

Analysis of multi-access performance on block cipher based FH sequences

Zan LI,Yi-lin CHANG,Jue-ping CAI

2005, 26(4):  130-134.  doi:1000-436X(2005)04-0130-05

Asbtract ( 21 )   HTML ( 3)   PDF (620KB) ( 193 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

Based on the 3DES block cipher frequency-hopping (FH) sequences, the paper suggests a kind of packet protocol for frequency-hopping multiple-access (FHMA) networks. In theory, the performance of the packet error and the throughput of FHMA network are derived, which shows that the ratio of the packet length M to the frequency-hopping slots q is the most key parameter to determine the FHMA system performance under the condition of large user number. Computer simulation results of block cipher based FH sequences compared with those of the logistic chaotic sequences are also included to support our development.

Academic communication

Cache consistency strategy based on GPRS networks

Jin TAN,Guang-xi ZHU

2005, 26(4):  135-141.  doi:1000-436X(2005)04-0135-07

Asbtract ( 23 )   HTML ( 2)   PDF (547KB) ( 101 )   Knowledge map   

Figures and Tables | References | Related Articles | Metrics

A strategy of maintaining cache consistency in wireless mobile computing environments was provided, which added a VS server into the GPRS network, utilized the location information of mobile terminal in SGSN located at GPRS backbone and locality of user access, just sent invalidation information to mobile terminal which was online in accordance with the cached data, and reduced the information amount in asynchronous transmission. The performance analyses indicate that this strategy can simplify the complexity of maintaining cache consistency, support arbitrary disconnection intervals of mobile terminal and roaming in a PLMN with very little computing amount.