检索结果-南通市图书馆

A novel mapping scheme and modified decoding algorithm for BICM-ID

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

High Technology Letters 2013年第1期19卷 70-75页

作者：方伟伟 Li Jianping Cai Chaoshi school of information engineering Communication University of China

This paper proposes a novel mapping scheme for bit-interleaved coded modulation with iterative decoding(BICM-ID).The symbol mapping is composed of two QPSK with different radiuses and phases,called cross equalization-8PSK-quasi-semi set partitioning(CE-8PSK-Quasi-SSP).Providing the same average power,the proposed scheme can increase the minimum squared Euclidean distance(MSED)and then improve the receiving performance of BICM-ID compared with conventional symbol mapping ***,a modified iteration decoding algorithm is proposed in this *** the process of iteration decoding,different proportion of the extrinsic information to the systematic observations results in distinct decoding *** high SNR(4~9dB),the observation information plays a more important role than the extrinsic *** results show that the proportion set at 1.2 is more suitable for the novel mapping in *** the BER is 10^(-4),more than 0.9dB coding gain over Rayleigh channels can be achieved for the improved mapping and decoding scheme.

关键词： bit-interleaved coded modulation with iterative decoding (BICM-ID) minimum squared Euclidean distance (MSED) average power tioning ( CE-8PSK-Quasi-SSP) extrinsic information cross equalization-8PSK-quasi-semi set parti- priori information weighted coefficient

Weighted Discriminative Sparse Coding for Image Classification

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2014年第1期23卷 104-108页

作者： ZHANG Lihe ZHANG Kunyu school of information and communication engineering Dalian University of Technology

In the discriminative sparse coding,the reconstruction residual over each class-specific subdictionary can provide great discriminative and label information. In this paper, we propose a weighted discriminative sparse coding method by using the residual as the weight. For a test sample, we first compute its sparse code over each learnt sub-dictionary, and then use the reconstruction residual over each sub-dictionary to weight the corresponding sub-dictionary, thereby forming a weighted sample-specific structure dictionary, over which we compute a new sparse code for the test sample. This code carries more discriminative information about interclass difference. Our method yields a unique structure dictionary for each test sample, so that samples with the same class labels have more similar distributions of dictionary atom contributions. Experimental results demonstrate that the proposed method outperforms some state-of-the-art methods under the same learning conditions.

关键词： Image classification Discrimination sparse representation Reconstruction residual

Dynamic spectrum allocation for cell range extension in tiered Macro-Pico heterogeneous networks

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2013年第1期20卷 66-72页

作者： TIAN Peng TIAN Hui GAO Li-qi ZHANG Jun WANG Meng school of information and communication engineering Beijing University of Posts and Telecommunications

Heterogeneous networks are employed in the next generation communication systems to enhance the area spectral efficiency （ASE）, where cell range extension （CRE） is a promising technique to improve the cell edge performance and utilize the low power node （LPN） resources more effectively. In this paper we propose a dynamic spectrum aUocation scheme for Macro-Pico scenario to mitigate both the co-tier and cross-tier interferences. The available system spectrum is divided into different parts by four steps, i.e. user set partition, service request collection, cross-tier occupation and CRE occupation decision, while the service request of each user is taken into consideration. During the process implementation, the reference signal receiving power （RSRP） threshold is derived by mathematical means to judge cell edge macro users when a predefined ratio is given. Simulation results show that the proposed scheme reaches almost the same cell edge performance with the best existing option, meanwhile provides higher overall system throughput and better spectral efficiency. Therefore, much better balance is achieved.

关键词： spectrum allocation heterogeneous network elCIC range extension pico cells

Virtual Network Embedding Algorithm for Load Balance with Various Requests

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2014年第2期23卷 382-387页

作者： WANG Li QU Hua ZHAO Jihong school of Electronic and information engineering Xi'an Jiaotong University school of communication and information engineering Xi'an University of Posts and Telecommunications

Virtual network embedding(VNE) is a crucial technology for network virtualization to allocate network resource. Virtual network request in which node and link resource have great disparity will lead to unbalanced resource distribution and lower acceptance ratio of virtual network requests. In this paper, we provide a virtual network embedding algorithm for load balance with various requests. It maps virtual nodes to substrate nodes of which node link residual resource ratio is closest to that of virtual nodes, and then maps the virtual link to physical path using shortest path first algorithm with the link node residual resource ratio constraint. Simulation shows that the provided algorithm can get higher acceptance ratio and network resource utilization for load balance.

关键词： Virtual network embedding Load balance Heuristic algorithm Node mapping Link mapping

Early termination strategy of HEVC based on statistical models

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2019年第5期26卷 72-81页

作者： Liu Yitong Tian Wang Li Yuchen Yang Hongwen school of information and communication engineering Beijing University of Posts and Telecommunications

High efficiency video coding(HEVC)uses half of the bitrate compared to H.264/advanced video coding(AVC)for encoding the same sequence with similar *** of the advanced hierarchical structures of coding units(CUs),predicting units(PUs),and transform units(TUs),HEVC can better adapt when encoding full high definition(HD)and ultra high definition(UHD)*** the expense of encoding efficiency,the complexity of HEVC sharply increases compared to H.264/AVC,mainly due to its quad-tree structure that splits *** this study,the probability distribution,which is generated by a rate distortion optimizing(RDO)cost,is ***,an early terminating method is proposed to decrease the complexity of the HEVC based on probability *** experiment shows that the coding time is reduced by 44.9%for HEVC intra coding,at the cost of a 0.61%increase in the Bj?ntegaard delta rate(BD-rate),on average.

关键词： HEVC early termination statistical model fast algorithm

Strip silicon waveguide for code synchronization in all-optical analog-to-digital conversion based on a lumped time-delay compensation scheme

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2016年第4期25卷 175-181页

作者：李莎石志国康哲余重秀王建萍 school of Computer and communication engineering University of Science and Technology Beijing (USTB ) Beijing 100083 China State Key Laboratory of information Photonics and Optical communications Beijing University of Posts and Telecommunications (BUPT) Beijing 100876 China

An all-optical analog-to-digital converter （ADC） based on the nonlinear effect in a silicon waveguide is a promising candidate for overcoming the limitation of electronic devices and is suitable for photonic integration. In this paper, a lumped time-delay compensation scheme with 2-bit quantization resolution is proposed. A strip silicon waveguide is designed and used to compensate for the entire time-delays of the optical pulses after a soliton self-frequency shift （SSFS） module within a wavelength range of 1550 nm-1580 nm. A dispersion coefficient as high as -19800 ps/（***） with ＋0.5 ps/（***） variation is predicted for the strip waveguide. The simulation results show that the maximum supportable sampling rate （MSSR） is 50.45 GSa/s with full width at half maximum （FWHM） variation less than 2.52 ps, along with the 2-bit effective- number-of-bit and Gray code output.

关键词： all-optical analog-to-digital conversion silicon waveguide soliton self-frequency shift time-delaycompensation

Transmission capacity for inhomogeneous overlaid wireless Ad-hoc networks

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2013年第3期20卷 8-12,25页

作者： LIU Yang GAO Jing SUN Xiao-hui YIN Chang-chuan school of information and communication engineering Beijing University of Posts and Telecommunications

In the analysis of overlaid wireless Ad-hoc networks, the underlying node distributions are commonly assumed to be two independent homogeneous Poisson point processes. In this paper, by using stochastic geometry tools, a new inhomogeneous overlaid wireless Ad-hoc network model is studied and the outage probability are analyzed. By assuming that primary （PR） network nodes are distributed as a Poisson point process （PPP） and secondary （SR） network nodes are distributed as a Matern cluster processes, an upper and a lower bounds for the transmission capacity of the primary network and that of the secondary network are presented. Simulation results show that the transmission capacity of the PR and SR network will both have a small increment due to the inhomogeneity of the SR network.

关键词： transmission capacity Ad-hoc network PPP Matem cluster process

Service-oriented network performance evaluation framework based on LA-FAHP

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2015年第3期22卷 74-83页

作者： Zhao Xing Lu Zhaoming Wang Luhan Wen Xiangming Lei Tao school of information and communication engineering Beijing University of Posts and Telecommunications

Since the different characteristics of various network services determine that their requirements for network are also disparate, the performance of one network varies according to the services running on it. However, most of previous network performance evaluation （NPE） researches conduct evaluations based on the network parameters, but without considering from the perspective of specific service running on the network. In view of this issue, a novel service-oriented NPE framework is proposed. First, the characteristics discrepancy among different types of services are investigated. Next, in order to conduct comprehensive evaluation of multiple services, an enhanced low-complexity adaptive （LA）-fuzzy analytical hierarchy process （FAHP） is introduced; meanwhile by applying the experts-construct-directly （ECD） algorithm proposed later, the consistency check required in previous studies can be omitted, thereby significantly reducing the computation complexity and assessment workload for experts. Then, in accordance with the features of each service, corrections are made to their respective membership functions, thus making the proposed LA-FAHP adaptive to various service evaluation scenarios. The subsequent comparison with other NPE methods well proves the effectiveness and high sensitivity of proposed framework, and the analysis verifies the low computation complexity of the proposed algorithms as well.

关键词： network performance evaluation low-complexity adaptive- fuzzy analytical hierarchy process (LA- FAHP) service-oriented

Joint Optimization of Channel Allocation,Link Assignment and Power Control for Device-to-Device communication Underlaying Cellular Network

在线全文

学校读者我要写书评

暂无评论

China communications 2015年第12期12卷 92-100页

作者： TANG Rui ZHAO Jihong QU Hua school of Electronics and information engineering Xi'an Jiaotong University school of communication and information engineering Xi'an University of Posts and Telecommunications

Device-to-Device(D2D) communication has been proposed to facilitate cellular network with system capacity(SC) and quality of service(QoS).We consider the design of link assignment(LA),channel allocation(CA)and power control(PC) in D2D-aided content delivery scenario for both user fairness(UF)and system throughput(ST) under QoS *** to the complexity of the problem,we decompose it into two components:CA is formulated from graph perspective to mitigate severe co-channel interference,which turns out to be the Max K-cut problem;LA and PC are jointly optimized to utilize the gain achieved from CA for supreme performance,and specifically,genetic algorithm(GA) is adopted to optimize LA,but when deriving the fitness of each chromosome,PC optimization will be *** to numerical results,we elucidate the efficacy of our scheme.

关键词： decompose utilize links formulated constraint facilitate optimize requirement fitness throughput