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2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.最新文献

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Short-window spectral analysis using AMVAR and multitaper methods 利用AMVAR和多锥度方法进行短窗光谱分析
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458364
N. Hariharan
{"title":"Short-window spectral analysis using AMVAR and multitaper methods","authors":"N. Hariharan","doi":"10.1109/SPCOM.2004.1458364","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458364","url":null,"abstract":"In this paper, we compare two popular methods for estimating power spectrum for short time series, namely adaptive multivariate autoregressive (AMVAR) method and the multitaper method. By analyzing a simulated signal (embedded in a background Ornstein-Uhlenbeck noise process) we demonstrate that the AMVAR method performs better for very short data when compared to the multitaper method. We also show that coherence can still be detected in noisy bivariate time series data even if the individual power spectra fail to show any peaks.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114237743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
2-D complex wavelet transforms for identification of wave-like features in geophysical data 二维复小波变换识别地球物理资料中的类波特征
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458388
A. Piyush Shanker, R. Nanjundiah
{"title":"2-D complex wavelet transforms for identification of wave-like features in geophysical data","authors":"A. Piyush Shanker, R. Nanjundiah","doi":"10.1109/SPCOM.2004.1458388","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458388","url":null,"abstract":"The power spectrum of a two-dimensional (2-D) space-time data set is computed using a 2-D extension of the Continuous Morlet Wavelet Transform. By means of this method, the power spectra in 4-D space (spatial scale-time period-space-time) can be estimated. This method is very useful in analyzing waves as it enables us to track the variation of frequency and amplitude of a wave with time and space. The method has an added advantage that we can obtain the predominant spatial scales over a particular region, the temporal scales associated with them and their time of occurrence. An example of it's application to study the features of poleward propagation of monsoons over the Indian longitudes and the pacific is given. This method can be extended for application to multi-dimensional datasets.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114570204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Speaker-specific information from residual phase 来自剩余相位的特定于说话人的信息
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458513
K. Sri Rama Murty, S. R. Mahadeva Prasanna, B. Yegnanarayana
{"title":"Speaker-specific information from residual phase","authors":"K. Sri Rama Murty, S. R. Mahadeva Prasanna, B. Yegnanarayana","doi":"10.1109/SPCOM.2004.1458513","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458513","url":null,"abstract":"This paper demonstrates the presence of speaker-specific information in the residual phase using autoassociative neural network (AANN) models. The residual phase is extracted from the speech signal after eliminating the vocal tract information by the linear prediction (LP) analysis. AANN models are used for capturing the speaker-specific information present in the residual phase. The speaker recognition studies infer that the residual phase contains significant speaker-specific information and it is indeed captured by the AANN models. In this study we also demonstrate that in voiced speech segments, regions around the instants of glottal closure are more speaker-specific compared to other regions.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130897403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 22
Image steganography for wireless networks using the Hadamard transform 利用Hadamard变换的无线网络图像隐写
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458371
S. Pal, P. Saxena, S. K. Muttoo
{"title":"Image steganography for wireless networks using the Hadamard transform","authors":"S. Pal, P. Saxena, S. K. Muttoo","doi":"10.1109/SPCOM.2004.1458371","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458371","url":null,"abstract":"The discrete Hadamard transform (DHT) is a simple orthogonal transformation with a set of unique properties. Its 2D version has a separable kernel and can be implemented using fast algorithms. This paper exploits the power of DHT for carrying out steganography using images as containers of hidden information. Computational simplicity and scope for efficient and compact hardware realization makes the scheme suitable for mobile applications. By manipulating different sets of coefficients in the Hadamard transform-domain it is possible to practice steganography satisfying different criteria like transparency, capacity and survivability. It is also shown that this transform has an edge over many other popular transforms for data embedding in real-time over resource constrained wireless networks.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127017307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 11
Design of low-complexity linear dispersion codes 低复杂度线性色散码的设计
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458502
D. Marathe, A. Tandon
{"title":"Design of low-complexity linear dispersion codes","authors":"D. Marathe, A. Tandon","doi":"10.1109/SPCOM.2004.1458502","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458502","url":null,"abstract":"We consider the design of space-time codes that offer low decoding complexity. It is well known that for codes based on orthogonal designs, maximum-likelihood (ML) decoding reduces to symbol-by-symbol decoding. However, this simplicity of decoding is achieved at the expense of symbol rate. It is natural to ask if the symbol rate can be increased if the code construction allows ML decoding to reduce to pairwise decoding of symbols. Our work attempts to answer this question by describing a method of designing pairwise decodable codes for any number of transmit antennas based on the linear dispersion (LD) code framework. We then show that for codes designed using this method, ML decoding can be reduced to pairwise decoding of symbols. For the case of M=3 and M=4 transmit antennas, we provide error-performance simulation results for these codes.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127536402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Wideband space-time communication: from propagation-based models to information-theoretic design prescriptions 宽带时空通信:从基于传播的模型到信息论的设计处方
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458346
G. Barriac, N. Jacobsen, Upamanyu Madhow
{"title":"Wideband space-time communication: from propagation-based models to information-theoretic design prescriptions","authors":"G. Barriac, N. Jacobsen, Upamanyu Madhow","doi":"10.1109/SPCOM.2004.1458346","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458346","url":null,"abstract":"While much of the activity on space-time, or multi-antenna, communication has focused on narrowband indoor systems, in this work, we consider the complementary setting of wideband outdoor channels typical of fourth generation cellular and fixed wireless systems, with a focus on orthogonal frequency division multiplexing (OFDM). Starting from propagation studies available in the literature, we obtain an analytical framework for information-theoretic design prescriptions that, compared to conventional space-time communication strategies, improve performance while reducing transceiver complexity. We introduce the notion of implicit feedback, applicable to both TDD and FDD systems, in which the base station learns the spatial covariance of the downlink spatial channel by averaging uplink measurements across frequency. We develop rules of thumb for optimizing antenna spacing for systems with such \"free\" feedback and show that the number of antennas at the base station can be scaled up, thus increasing the beamforming gain, without any increase in complexity at the mobile. Spatial covariance estimation also simplifies receiver processing on the uplink, enabling a novel method of noncoherent eigenbeamforming, which yields beamforming gains without explicit channel estimation. Key to these results is the observation that, for appropriately spaced antenna elements, a typical outdoor cellular channel has a small number of dominant spatial eigenmodes, even as the number of antenna elements at the base station is scaled up.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127312755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Distributed range assignment for reliable channel access and reuse in ad-hoc networks ad-hoc网络中可靠信道访问和复用的分布式范围分配
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458377
Gaura v Snvastava, Paul Bousread
{"title":"Distributed range assignment for reliable channel access and reuse in ad-hoc networks","authors":"Gaura v Snvastava, Paul Bousread","doi":"10.1109/SPCOM.2004.1458377","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458377","url":null,"abstract":"The available bandwidth in an ad-hoc network can decrease rapidly due to the shared access to the communication channel. Power control can enhance the available bandwidth by allowing non-interfering nodes to communicate simultaneously. A number of power aware topology control algorithms have been proposed, where low power transmissions are used to forward data. However evaluating the power level for the data packets is not sufficient. Reliable transmission of the data packets in a shared channel network requires a number of signalling messages at the medium access channel (MAC) layer. The transmission power of the signalling messages is crucial for both reliable access and channel reuse. We propose a distributed range assignment algorithm (DRA). That can be applied to a power aware topology control algorithm, to evaluate an appropriate power for the signalling messages. A worked example and a simulation based analysis of DRA applied to a Distributed Relative Neighbourhood Graph is provided. Furthermore, a study on the impact of the transmission range, on the power usage and channel reuse is conducted.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"114 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128172573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Analysis of optical waveguide grating filter for optical wireless communication 光无线通信用光波导光栅滤波器分析
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458498
L. Suresh, S. Ponmalar, S. Sundaravadivelu
{"title":"Analysis of optical waveguide grating filter for optical wireless communication","authors":"L. Suresh, S. Ponmalar, S. Sundaravadivelu","doi":"10.1109/SPCOM.2004.1458498","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458498","url":null,"abstract":"Efficient coupling of light between the waveguides is a key issue in the design of many optical components that can be used in wireless optical communication systems. In order to have a large scale photonic integrated circuits it is required to integrate several optical components. This will result in a high density, three-dimensional structure, based on a single substrate. This paper realizes highly efficient optical filters, using grating structures to provide sharp cutoff. The coupled mode theory (CMT) is used for the analysis of symmetric, antisymmetric, reflection and transmission modes. Here we propose a novel approach for analyzing a fiber-grating filter in transmission mode. This device can act as a narrow band pass filter and particularly useful in optical wireless applications.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"215 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131899128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
High-rate full-rank space-time block codes from Cayley algebra 凯莱代数的高速率全秩空时分组码
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458506
T. Kiran, B. Sundar Rajan
{"title":"High-rate full-rank space-time block codes from Cayley algebra","authors":"T. Kiran, B. Sundar Rajan","doi":"10.1109/SPCOM.2004.1458506","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458506","url":null,"abstract":"For a quasi-static, multiple-input multiple-output (MIMO) Rayleigh fading channel, high-rate space-time block codes (STBCs) with full-diversity have been constructed in B. A. Sethuraman et al., (2003) for arbitrary number of transmit antennas, by using the regular matrix representation of an associative division algebra. While the 2/spl times/2 as well as 4/spl times/4 real-orthogonal design (ROD) V. Tarokh et al., (1999) and Alamouti code S. M. Alamouti (1998) were obtained as a special case of this construction, the 8/spl times/8 ROD could not be obtained. In this paper, starting with a non-associative division algebra (Cayley algebra or more popularly known as octonion algebra) over an arbitrary characteristic zero field F, a method of embedding this algebra into the ring of matrices over F is described, and high-rate full-rank STBCs for 8m (m, an arbitrary integer) antennas are obtained. We also give a closed form expression for the coding gain of these STBCs. This embedding when specialized to F=/spl Ropf/ and m=1, gives the 8/spl times/8 ROD.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123899317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
Fractional Fourier transform based beamforming in micro-cellular environment of wireless communication systems 微蜂窝环境下基于分数阶傅立叶变换的无线通信系统波束形成
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458527
R. Khanna, R. Saxena
{"title":"Fractional Fourier transform based beamforming in micro-cellular environment of wireless communication systems","authors":"R. Khanna, R. Saxena","doi":"10.1109/SPCOM.2004.1458527","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458527","url":null,"abstract":"The next generation mobile services like variable bandwidth; desktop/multimedia with mobility and service personalization shall be enabled by putting new technologies and systems in use. In order to provide these services in wireless fashion the requirements on data rate, link quality, spectral efficiency, and mobility cannot be met with conventional beamforming. Therefore new beamforming techniques are essential to increase the spectral efficiency of wireless communication systems. In this paper a fractional Fourier transform (FrFT) based optimal beamforming in micro-cellular environments over AWGN channel is considered for reducing MSE at no extra computational cost. The results are achieved by use of FrFT based beamforming for a moving and accelerating source in a micro-cellular environment.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128605758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
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