检索结果-内蒙古大学图书馆

QUASI-SYNCHRONOUS MULTICARRIER DS-CDMA USING Z-COMPLEMENTARY SEQUENCES

Journal of Electronics(China) 2009年第4期26卷 487-491页

作者： Tu Yifeng Fan Pingzhi Yuan Weina Hao Li Provincial Key Lab of Information Coding ＆ Transmission Institute of Mobile Communications Southwest Jiaotong University Chengdu 510031 China School of Information Science ＆ Engineering East China University of Science ＆ Technology Shanghai 200092 China

In this paper, a multicarrier DS-CDMA system which employs Z-Complementary Se- quences (ZCS) as spreading code is investigated. The new system can not only eliminate multipath interference and Multiple Access Interference (MAI), but also support flexible number of users com- pared with system using Orthogonal Complementary (OC) codes. Multicarrier DS-CDMA using OC codes can be regarded as a special case of our proposed system. Zero Correlation Zone (ZCZ) of ZCS can be flexibly adjusted to meet the requirements on the user number and maximum multipath and in- ter-user delay, in this way, more users can be supported without losing interference-free property. The effectiveness of the proposed system is validated through theoretical analysis and simulation results.

关键词： Orthogonal Complementary (OC) codes Multicarrier DS-CDMA Z-Complemen-tary Sequences (ZCS) Zero Correlation Zone (ZCZ)

来源：评论

学校读者我要写书评

暂无评论

A Deep-Neural-Network-Based Hybrid Method for Semi-Supervised Classification of Polarimetric SAR Data 6

A Deep-Neural-Network-Based Hybrid Method for Semi-Supervise...

引用

6th Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2019

作者： Liu, Chi Liao, Wenzhi Li, Heng-Chao Huang, Shaoguang Philips, Wilfried TELIN-IPI IMEC-Ghent University Ghent Belgium Sichuan Provincial Key Laboratory of Information Coding and Transmission Southwest Jiaotong University Chengdu China

ISBN: (纸本)9781728129129

This paper proposes a deep-neural-network-based semi-supervised method for polarimetric synthetic aperture radar (PolSAR) data classification. The proposed method focuses on achieving a well-trained deep neural network (DNN) when the amount of the labeled samples is limited. In the proposed method, the probability vectors, where each entry indicates the probability of a sample associated with a category, are first evaluated for the unlabeled samples, leading to an augmented training set. With this augmented training set, the parameters in the DNN are learned by solving the optimization problem, where the log-likelihood cost function and the class probability vectors are used. To alleviate the 'salt-and-pepper' appearance in the classification results of PolSAR images, the spatial interdependencies are incorporated by introducing a Markov random field (MRF) prior in the prediction step. The experimental results on two realistic PolSAR images demonstrate that the proposed method effectively incorporates the spatial interdependencies and achieves the good classification accuracy with a limited number of labeled samples. © 2019 IEEE.

关键词： Deep neural networks

来源：评论

学校读者我要写书评

暂无评论

A cross-layer fast handoff protocol for vehicle communication system

A cross-layer fast handoff protocol for vehicle communicatio...

引用

IET Conference on Wireless, Mobile and Sensor Networks 2007, CCWMSN'07

作者： Meng, Xie Xuming, Fang Qiang, Shen Provincial Key Lab. of Information Coding and Transmission Southwest Jiaotong University Chengdu 610031 China National Mobile Communication Research Lab. Southeast University Nanjing 210096 China

ISBN: (纸本)9780863418365

The main purpose of handoff protocol is to provide high data rate and seamless supporting real-time services in the vehicle communication system. Potentially, Wireless Mesh Network (WMN) is one of the best answers to the vehicle communication system. How to provide efficient handoff protocol in the vehicle communication system is the major issue of our design. We analyzed the mathematical module of the vehicle communication system in this paper. Then considering a typical vehicle communication system, we propose a Cross-layer Fast Handoff Protocol (CFHP) which takes into account the signal strength, hops and link state. Compared with the existing AODV based handoff protocols, our protocol with fast handoff mechanism improves the system throughput and the delivery ratio significantly.

关键词： information services

来源：评论

学校读者我要写书评

暂无评论

A Pricing and Game Theory-based Call Admission Control Scheme for CDMA Systems

A Pricing and Game Theory-based Call Admission Control Schem...

引用

第三届IEEE无线通讯、网络技术暨移动计算国际会议

作者： Hui Zhang Xuming Fang Provincial Key Lab of Information Coding and Transmission Southwest Jiaotong University Chengdu 6 Provincial Key Lab of Information Coding and Transmission Southwest Jiaotong University Chengdu 6

Call admission control (CAC) is one of the most important parts in radio resource management of CDMA networks, and it has an important effect on the quality of service (QoS). The most concern of traditional CAC strategies is to harmonize the blocking probability and dropping probability, so as to maximize the resource utility. With the development of radio network, not only resource utility is the emphasis of CAC but also fairness is becoming important. In the multimedia CDMA networks, once the high load stream traffic is admitted, it will over-use the resource greedily, which will cause the unfair use of the resource to other kinds of traffic. In this paper, by using Cobb-Douglas utility function to construct a price function, we achieve the fairness of resource utilization in different load condition. Since video and IPTV can tolerate a certain degree of packet lose rate and the data can tolerate a certain degree of delay, so we use a game to decide whether to degrade ongoing users (i.e., discard some packets of video or IPTV, or stop the service of data) or to reject the new user in order to maximize the resource utility in the precondition of fairness of resource utilization. The analysis and simulation results show that, by using this pricing function and game approach, the fairness of resource utilization is well achieved, while the resource utilization is maximized.

关键词： admission control Cobb-Douglas pricing function game theory Nash equilibrium blocking probability fairness

来源：评论

学校读者我要写书评

暂无评论

An improved AODV routing protocol with network coding in wireless ad hoc network

An improved AODV routing protocol with network coding in wir...

引用

IET Conference on Wireless, Mobile and Sensor Networks 2007, CCWMSN'07

作者： Xiang, Zheng Fang, Xuming Key Lab. of Information Coding and Transmission Sichuan Province Southwest Jiaotong University Chengdu 610031 Sichuan China

ISBN: (纸本)9780863418365

This paper introduces a practical scheme in order to improve multi-hop throughput as well as to minimize packet's average end to end delay by incorporating network coding, which is at present a widely discussed technique in multicast, with AODV in wireless Ad Hoc networks. This scheme is simple and easily implemented with modest overhead, and the simulation results show that this scheme can achieve higher throughput and much smaller packet's average end to end delay in certain network topology.

关键词： Routing protocols

来源：评论

学校读者我要写书评

暂无评论

Quadriphase Z-complementary sequences

Quadriphase Z-complementary sequences

引用

作者： Li, Xudong Fan, Pingzhi Tang, Xiaohu Hao, Li Key Lab of Information Coding and Transmission Institute of Mobile Communications Southwest Jiaotong University Chengdu Sichuan 610031 China

Aperiodic quadriphase Z-complementary sequences, which include the conventional complementary sequences as special cases, are introduced. It is shown that, the aperiodic quadriphase Zcomplementary pairs are normally better than binary ones of the same length, in terms of the number of Z-complementary pairs, and the maximum zero correlation zone. New notions of elementary transformations on quadriphase sequences and elementary operations on sets of quadriphase Zcomplementary sequences are presented. In particular, new methods for analyzing the relations among the formulas relative to sets of quadriphase Zcomplementary sequences and for describing the sets are proposed. The existence problem of Z-complementary pairs of quadriphase sequences with zero correlation zone equal to 2, 3, and 4 is investigated. Constructions of sets of quadriphase Z-complementary sequences and their mates are given. Copyright © 2010.

关键词： Elementary operations Elementary transformations Mates Quadriphase sequences Z-complementarity Zero correlation zone

来源：评论

学校读者我要写书评

暂无评论

New families of binary sequences with low correlation and large size

New families of binary sequences with low correlation and la...

引用

作者： Zhou, Zhengchun Tang, Xiaohu Department of Applied Mathematics School of Information Science and Technology Southwest Jiaotong University Chengdu China Provincial Key Lab of Information Coding and Transmission Institute of Mobile Communications Southwest Jiaotong University Chengdu China

In this paper, for odd n and any k with gcd(n, k) = 1, new binary sequence families Sk of period 2n-1 are constructed. These families have maximum correlation 1+2n+3/2, family size 22n +2n +1 and maximum linear span n(n+1)/2 . The correlation distribution of Sk is completely determined as well. Compared with the modified Gold codes with the same family size, the proposed families have the same period and correlation properties, but larger linear span. As good candidates with low correlation and large family size, the new families contain the Gold sequences and the Gold-like sequences. Furthermore, Sk includes a subfamily S1k which has the same period, correlation distribution, family size and linear span as the family S o(2) recently constructed by Yu and Gong. In particular, when k = 1, S1k is exactly So(2). Copyright © 2009 The Institute of Electronics, information and Communication Engineers.

关键词： Binary sequences

来源：评论

学校读者我要写书评

暂无评论

Change detection based GγR-GKIT on SAR amplitude image 9

Change detection based GγR-GKIT on SAR amplitude image

引用

9th European Conference on Synthetic Aperture Radar, EUSAR 2012

作者： Wang, Hu-Qing Li, Heng-Chao Huang, Ping-Ping Sichuan Provincial Key Laboratory of Information Coding and Transmission Southwest Jiaotong University Chengdu 610031 China College of Information Engineering Inner Mongolia University of Technology Hohhot010051 China

ISBN: (纸本)9783800734047

In this paper, a novel approach to change detection from synthetic aperture radar (SAR) amplitude imagery is presented. In particular, a parametric pdf is proposed to model the ratio image, which is based on an efficient statistical model generalized Gamma distribution (GγD). The GγD forms a large variety of alternative distributions and is flexible to model the SAR images covering different kinds of surfaces in amplitude and intensity formats. In addition, a SAR specific parametric modeling approach and a suitable parameter-estimation based on the method of log-cumulants (MoLC) of the generalized Gamma ratio (GγR) distribution are adopted. Specifically, due to the considerable non-Gaussianity of SAR amplitude ratio data, the aforementioned parametric modeling approach for the ratio image is integrated into the generalized Kittler and Illingworth minimum-error thresholding (GKIT) process which allows one to take into account non-Gaussian data. Experimental results obtained confirm the effectiveness of the proposed approach.

关键词： Synthetic aperture radar

来源：评论

学校读者我要写书评

暂无评论

Low correlation zone sequences from interleaved construction

Low correlation zone sequences from interleaved construction

引用

作者： Parampalli, Udaya Tang, Xiaohu Department of Computer Science and Software Engineering University of Melbourne VIC 3010 Australia Provincial Key Lab of Information Coding and Transmission Institute of Mobile Communications Southwest Jiaotong University Chengdu China

Recently there has been a surge of interest in construction of low correlation zone sequences. The purpose of this paper is to survey the known results in the area and to present an interleaved construction of binary low correlation zone sequences. The interleaved constructionunifies many constructions currently available in the literature. These sequences are useful in quasi-synchronous code-division multiple access (QS-CDMA) communication systems. Copyright © 2010.

关键词： Code division multiple access

来源：评论

学校读者我要写书评

暂无评论

Performance analysis of multiuser receivers for large CDMA random access systems over Rayleigh fading channels

Performance analysis of multiuser receivers for large CDMA r...

引用

2009 4th International Conference on Communications and Networking in China, CHINACOM 2009

作者： Yu, Kai Fan, Pingzhi Hao, Li Key Lab. of Information Coding and Transmission Institute of Mobile Communications Southwest Jiaotong University Chengdu Sichuan 610031 China

ISBN: (纸本)9781424443376

The random access systems, exploiting multiuser detectors such as MMSE detector and decorrelator, over large random spreading CDMA channel subject to Rayleigh fading is investigated, under the assumption of infinite number of users, infinite spreading gain, and their ratio converging to a constant. The signal to interference ratio (SIR) is shown to converge almost surely to a constant and the bit-error rate (BER) limit is a function of the transmission probability and traffic load. The throughput and spectrum efficiency are analyzed, and confirmed by simulation results.

关键词： Fading channels

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：