中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0001-05
摘要 ( 3326 ) PDF (103 KB)( 366 )
The concepts on information and communication technology (ICT) and “intelligence” are defined firstly and the environment and requirements for ICT are then analyzed. Based on the definitions and the analyses given, a survey on intelligence approaches for ICT is thus made. The major conclusion drawn from the survey is a recommendation saying that intelligence approaches are becoming the nucleus for further development of the entirety of ICT and therefore should receive much more attentions from ICT researchers in the coming years.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0006-05
摘要 ( 2528 ) PDF (278 KB)( 384 )
One of the biggest challenges in ultra-wideband (UWB) radio is the accurate timing acquisition for the receiver. In this article, we develop a novel data-aided synchronization algorithm for pulses amplitude modulation (PAM) UWB systems. Pilot and information symbols are transmitted simultaneously by an orthogonal code division multiplexing (OCDM) scheme. In the receiver, an algorithm based on the minimum average error probability (MAEP) of coherent detector is applied to estimate the timing offset. The multipath interference (MI) problem for timing offset estimation is considered. The mean-square-error (MSE) and the bit-error-rate (BER) performances of our proposed scheme are simulated. The results show that our algorithm outperforms the algorithm based on the maximum correlator output (MCO) in multipath channels.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0011-07
摘要 ( 2298 ) PDF (339 KB)( 454 )
This article presents the genetic algorithm (GA) as an autonomic approach for the joint radio resource management (JRRM) amongst heterogeneous radio access technologies (RATs) in the end-to-end reconfigurable systems. The joint session admission control (JOSAC) and the bandwidth allocation are combined as a specific decision made by the operations of the genetic algorithm with certain advisable modifications. The proposed algorithm is triggered on the following two conditions. When a session is initiated, it is triggered for the session to camp on the most appropriate RAT and select the most suitable bandwidth for the desired service. When a session terminates, it is also used to adjust the distribution of the ongoing sessions through the handovers. This will increase the adjustment frequency of the JRRM controller for the best system performance. Simulation results indicate that the proposed autonomic JRRM scheme not only effectively reduces the handover times, but also achieves well trade-off between the spectrum utility and the blocking probability.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0018-05
摘要 ( 2893 ) PDF (372 KB)( 382 )
In urban environment with serious blocking of direct paths, the non-line-of-sight (NLOS) propagation influences the location estimation accuracy. In this article, a novel algorithm is developed, which can mitigate the NLOS errors in location estimation significantly. Utilizing multiantenna array, the information of scatterers that cause the NLOS propagation is obtained. Then, we combine the information with TOA/TDOA based location algorithm to estimate the location of mobile station (MS). The simulation results show that our method can mitigate NLOS errors and enhance the location accuracy greatly.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0023-05
摘要 ( 3143 ) PDF (294 KB)( 387 )
In the transmitting, beamforming, and receiving combing (TBRC) MIMO system, a codebook based feedback strategy is usually used to provide the transmitter with the beamforming vector. The adopted codebook affects the system performance considerably. Therefore, the codebook design is a key technology in the TBRC MIMO system. In this article, the unitary space vector quantization (USVQ) codebook design criterion is proposed to design optimal codebooks for various spatial correlated MIMO channels. And the unitary space K-mean (USK) codebook generating algorithm is provided to generate the USVQ codebooks. Simulations show that the capacities of the feedback based TBRC systems using USVQ codebooks are very close to those of the ideal cases.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0028-04
摘要 ( 2208 ) PDF (240 KB)( 374 )
Q-ary low-density parity-check (Q-LDPC) codes have a better performance than those of the binary low-density parity-check (B-LDPC) codes, at short and medium block lengths, but the decoder of Q-LDPC has more complexity. In this article, a new stop criterion is proposed. By analyzing the changes of the maximum posteriori probability of the variable node, the criterion decides whether the iteration of the decoder must be stopped. The simulation results show that the stop criterion can effectively reduce the computation complexity of the Q-LDPC decoder with negligible performance loss.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0032-06
摘要 ( 2334 ) PDF (276 KB)( 448 )
It is well known that non-line-of-sight (NLOS) error has been the major factor impeding the enhancement of accuracy for time of arrival (TOA) estimation and wireless positioning. This article proposes a novel method of TOA estimation effectively reducing the NLOS error by 60%, comparing with the traditional timing and synchronization method. By constructing the orthogonal training sequences, this method converts the traditional TOA estimation to the detection of the first arrival path (FAP) in the NLOS multipath environment, and then estimates the TOA by the round-trip transmission (RTT) technology. Both theoretical analysis and numerical simulations prove that the method proposed in this article achieves better performance than the traditional methods.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0038-05
摘要 ( 2359 ) PDF (226 KB)( 453 )
A novel method which can detect the possible handoffs for mobile nodes is proposed in this article. The method can be deployed on mobile nodes. So when a possible handoff occurs, mobile nodes can detect and take some necessary actions in time. In this study, the method is also used to optimize the transmission mechanism of Q-TCP. Moreover, the simulation results show that Q-TCP can provide better quality of service (QoS) for mobile nodes when they are moving among different agents.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0043-05
摘要 ( 2385 ) PDF (221 KB)( 421 )
After analyzing the features of the Parlay application server (AS), which provides many services with different time constraints in the next generation network (NGN), a self- adapted overload control algorithm implemented in Parlay AS is proposed. In this algorithm, the service process module in parlay AS uses the earliest deadline first (EDF) serving rule to serve messages, and the overload control mechanism, using the Leaky Bucket algorithm to control message flows, is triggered by estimating the queue waiting time of a newly arriving message. By simulation it shows that this algorithm is a simple, easy-to-use, and available algorithm.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0048-07
摘要 ( 2900 ) PDF (368 KB)( 453 )
The difference in link condition of broadcast/ multicast users and the limitation of uplink resource, make it difficult to utilize adaptive modulation and coding (AMC) in the enhanced multimedia broadcast and multicast service (E-MBMS) network. To obtain the improvement of system throughput, this study proposes an adaptive modulation and coding scheme based on partial feedback, by which only partial users whose channel qualities are lower than the system threshold need to make a response to the modulation coding scheme (MCS) adaptation procedure. By this investigation, an adaptive scheme can be introduced in the E-MBMS network. Both the theoretical analysis and simulation results demonstrate the efficiency of the proposed strategy, in which the performance is close to the ideal one and has a significant throughput improvement when compared with that of the fixed MCS transmission scheme.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0055-06
摘要 ( 3966 ) PDF (291 KB)( 424 )
In both wireless local area networks (WLAN) and mobile ad hoc networks (MANET), the IEEE 802.11e medium access control (MAC) protocol is proposed for an effective quality of service (QoS) solution. A number of studies have been done to enhance the performance of 802.11e in MANET by independently adjusting contention window (CW) size of each access category (AC) in every node. However, without the cooperation between the high priority flows and lower priority flows, the QoS goal of high priority flows cannot achieve effectively. In this article, a fuzzy logic based cooperative MAC protocol (FLCMAC) is proposed to cooperate amongst network flows and dynamically adjust access probability of each low priority flow affecting the high priority flows to satisfy their QoS requirement. The simulation results indicate that compared to the enhanced distributed channel access (EDCA) scheme of 802.11e, the FLCMAC consistently excels, in terms of throughput and delay under moderate and heavy background traffic both in single-hop and multi-hop scenarios.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0061-07
摘要 ( 2435 ) PDF (345 KB)( 387 )
The quality, quantity, and consistency of the knowledge used in GO-playing programs often determine their strengths, and automatic acquisition of large amounts of high-quality and consistent GO knowledge is crucial for successful GO playing. In a previous article of this subject, we have presented an algorithm for efficient and automatic acquisition of spatial patterns of GO as well as their frequency of occurrence from game records. In this article, we present two algorithms, one for efficient and automatic acquisition of pairs of spatial patterns that appear jointly in a local context, and the other for deter- mining whether the joint pattern appearances are of certain significance statistically and not just a coincidence. Results of the two algorithms include 1 779 966 pairs of spatial patterns acquired automatically from 16 067 game records of profess- sional GO players, of which about 99.8% are qualified as pattern collocations with a statistical confidence of 99.5% or higher.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0068-07
摘要 ( 2567 ) PDF (416 KB)( 1553 )
Aiming to realize fast and accurate fault diagnosis in complex network environment, this article proposes a set of anomaly detection algorithm and intelligent fault diagnosis model. Firstly, a novel anomaly detection algorithm based on time series analysis is put forward to improve the generalized likelihood ratio (GLR) test, and thus, detection accuracy is enhanced and the algorithm complexity is reduced. Secondly, the intelligent fault diagnosis model is established by introducing neural network technology, and thereby, the anomaly information of each node in end-to-end network is integrated and processed in parallel to intelligently diagnose the fault cause. Finally, server backup solution in enterprise information network is taken as the simulation scenario. The results demonstrate that the proposed method can not only detect fault occurrence in time, but can also implement online diagnosis for fault cause, and thus, real-time and intelligent fault management process is achieved.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0075-05
摘要 ( 2137 ) PDF (263 KB)( 415 )
This article proposes a new algorithm of joint channel and carrier frequency-offset (JCCFO) estimation for multi-user multi-input and multi-output orthogonal frequency division multiplexing (MIMO-OFDM) systems. A least square (LS) channel estimation and a carrier frequency offset (CFO) correlation estimation are combined in this contribution. CFOs are generally estimated using training sequences in a special synchronization timeslot. In this contribution, CFO estimation is further improved by taking advantages of channel estimation based on pilot symbols in traffic timeslots. The CFOs can be first obtained from the primary channel estimation. And then, with the knowledge of the CFOs estimated, channel estimation can be enhanced greatly. Computer simulation results indicate that the proposed JCCFO scheme is of good performance. Besides, the computational complexity is low.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0080-05
摘要 ( 2169 ) PDF (265 KB)( 423 )
A call admission control scheme is proposed for real-time services in packet-switched orthogonal frequency division multiplexing (OFDM) wireless cellular networks. The main idea of the proposed scheme is to use maximum acceptance ratio to maintain maximum channel utilization for real-time services according to the desired packet-level and call- level quality-of-service (QoS) requirements. The acceptance ratio is periodically adjusted by using a time discrete Markov chain and Wiener prediction theory according to the varying traffic load. Extensive simulation results show that this algorithm maintains high channel utilization, even as it guarantees packet-level and call-level QoS requirements for real-time services.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0085-06
摘要 ( 3272 ) PDF (311 KB)( 387 )
Block diagonalization (BD) is an efficient precoding technique that eliminates inter-user interference in downlink multiple-input multiple-output (MIMO) systems. User selection strategies applied to multiuser MIMO systems with BD are investigated in this article. To enhance the capacity of multiuser MIMO systems, an equivalent capacity maximum (ECM) user selection strategy is proposed with low computational complexity. Considering both the factors of channel correlations and channel conditions, the proposed strategy can select a group of users to serve for maximizing the total throughput. Simulation results indicate that, for various channel conditions, proposed ECM strategy gains a better performance compared with traditional user selection strategies, and achieves a near optimal throughput as the exhaustive search.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0091-05
摘要 ( 2346 ) PDF (240 KB)( 367 )
Downlinks of the cellular systems generally have more transmit antennas than receive antennas. To efficiently exploit all antenna resources, a technique that combines the advantage of beamforming and spatial multiplexing has been proposed, which partitions the transmit antennas into neigh- boring sub-groups. In this article, this technique is further improved by Eq. (1) allowing non-contiguous antenna grouping, and Eq. (2) adopting two new grouping criteria: minimum signal distance maximization (MSDM) criterion and maximum correlation coefficient minimization (MCCM) criterion. Simulation results indicate that these improvements can bring noticeable gains in the Rayleigh flat fading channel environment.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0096-06
摘要 ( 2469 ) PDF (470 KB)( 431 )
In this article, the local anomalistic blocks such as crypts, furrows, and so on in the iris are initially used directly as iris features. A novel image segmentation method based on intersecting cortical model (ICM) neural network was introduced to segment these anomalistic blocks. First, the normalized iris image was put into ICM neural network after enhancement. Second, the iris features were segmented out perfectly and were output in binary image type by the ICM neural network. Finally, the fourth output pulse image produced by ICM neural network was chosen as the iris code for the convenience of real time processing. To estimate the performance of the presented method, an iris recognition platform was produced and the Hamming Distance between two iris codes was computed to measure the dissimilarity between them. The experimental results in CASIA v1.0 and Bath iris image databases show that the proposed iris feature extraction algorithm has promising potential in iris recognition.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0102-04
摘要 ( 3441 ) PDF (137 KB)( 396 )
In this article, a protocol for the teleportation of an unknown two-particle entanglement is proposed. The feature of the present protocol is that we utilize an asymmetric three- particle entangled state as the quantum channel. The optimal discrimination between two nonorthogonal quantum states is adopted. It is shown that an unknown two-particle entangled state can be probabilistically teleported from the sender to the remote receiver on condition that the co-sender successfully collaborates. The fidelity in this protocol is one. In addition, the probability of the successful teleportation is calculated and all kinds of transformations performed by the sender and the receiver are provided in detail.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0106-06
摘要 ( 3351 ) PDF (295 KB)( 385 )
generalized multi-protocol label switching (GMPLS- based) protection and restoration technologies will play significant role in next-generation broadband IP network to ensure the survivability. In this article, a systematic GMPLS-based recovery mechanism is proposed using enhanced link management protocol (LMP), which can support bidirectional fault notification relay more effectively. The major contributions and propositions in this article involve: 1) Soft-protection configuration for higher resource utilization with optimized routing; 2) Intelligent Shift from protection manner to restoration manner for the reduction of recovery latency; and 3) Toggleable revertive mode to increase restoration flexibility and to reduce loss of stability. Additionally, by leveraging valuable legacy including shared risk link group (SRLG) processing and fast reroute technique, the proposed recovery mechanism achieves higher resource utilization, fast and robust operation, satisfactory stability and flexibility, and is convenient in the application over heterogeneous transport networks.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0112-06
摘要 ( 3468 ) PDF (414 KB)( 444 )
It is crucial to design energy-efficient advanced encryption standard (AES) cryptography for low power embedded systems powered by limited battery. Since the S-Boxes consume much of the total AES circuit power, an efficient approach to reducing the AES power consumption consists in reducing the S-Boxes power consumption. Among various implementations of S-Boxes, the most energy-efficient one is the decoder-switch- encoder (DSE) architecture. In this paper, we refine the DSE architecture and propose one faster, more compact S-Boxes architecture of lower power: an improved and full-balanced DSE architecture. This architecture achieves low power consumption of 68 W at 10 MHz using 0.25 m 1.8V UMC CMOS technology. Compared with the original DSE S-Boxes, it further reduces the delay, gate count and power consumption by 8%, 14% and 10% respectively. At the sane time, simulation results show that the improved DSE S-Boxes has the best performance among various S-Boxes architectures in terms of power-area product and power-delay product, and it is optimal for implementing low power AES cryptography.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0118-05
摘要 ( 3766 ) PDF (216 KB)( 421 )
This article proposes a new algorithm to improve the rate control efficiency of enhanced reverse link medium access control (RLMAC) in the code division multiple access (CDMA) 1x EV-DO release A (Rev. A) system. The new algorithm brings reverse access terminal (AT) pilot power to the RLMAC rate control procedure and makes it easier for a low pilot power user to increase its data rate when the system is slightly loaded and harder to decrease its date rate when the system is heavily loaded. Numerical results of system level simulations show that the new algorithm can bring higher system throughput, lower AT transmission power, and lower system load.
中国邮电高校学报(英文版), 2008, 15 (1). doi： 1005-8885 (2008) 01-0123-06
摘要 ( 2312 ) PDF (220 KB)( 439 )
To improve the classification accuracy and reduce the training time, an intrusion detection technology is proposed, which combines feature extraction technology and multiclass support vector machine (SVM) classification algorithm. The intrusion detection model setup has two phases. The first phase is to project the original training data into kernel fisher discriminant analysis (KFDA) space. The second phase is to use fuzzy clustering technology to cluster the projected data and construct the decision tree, based on the clustering results. The overall detection model is set up based on the decision tree. Results of the experiment using knowledge discovery and data mining (KDD) from 99 datasets demonstrate that the proposed technology can be an an effective way for intrusion detection.