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IEEE Global Telecommunications Conference, 2004. GLOBECOM '04.最新文献

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Channel estimation for CDMA systems using iterative cancellations 基于迭代对消的CDMA系统信道估计
IEEE Global Telecommunications Conference, 2004. GLOBECOM '04. Pub Date : 2004-11-29 DOI: 10.1109/GLOCOM.2004.1378456
D. Borah
{"title":"Channel estimation for CDMA systems using iterative cancellations","authors":"D. Borah","doi":"10.1109/GLOCOM.2004.1378456","DOIUrl":"https://doi.org/10.1109/GLOCOM.2004.1378456","url":null,"abstract":"A matching pursuit followed by cancellation (MPC) algorithm is investigated for time-varying multipath channel estimation in asynchronous CDMA. The algorithm has significantly low computational complexity and consists of two steps. In the first step, a basic matching pursuit algorithm that identifies the strongest channel taps, and successively cancels them, is used. The second step of the algorithm uses the already estimated channel taps to remove interference from the received vector in order to identify the channel coefficients more accurately. The performance of the algorithm is characterized in terms of mean squared identification error (MSIE). The convergence behavior of MPC is described. A method to terminate the MP step of the algorithm successfully is proposed and is shown to perform well. Our results show that MPC achieves performance close to the Cramer-Rao lower bound (CRLB).","PeriodicalId":162046,"journal":{"name":"IEEE Global Telecommunications Conference, 2004. GLOBECOM '04.","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114425345","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
Frequency synchronization for generalized OFDMA uplink 广义OFDMA上行链路的频率同步
IEEE Global Telecommunications Conference, 2004. GLOBECOM '04. Pub Date : 2004-11-29 DOI: 10.1109/GLOCOM.2004.1378122
Zhongren Cao, U. Tureli, Yu-dong Yao, P. Honan
{"title":"Frequency synchronization for generalized OFDMA uplink","authors":"Zhongren Cao, U. Tureli, Yu-dong Yao, P. Honan","doi":"10.1109/GLOCOM.2004.1378122","DOIUrl":"https://doi.org/10.1109/GLOCOM.2004.1378122","url":null,"abstract":"In orthogonal frequency division multiple access (OFDMA), the total spectral resource is partitioned into multiple orthogonal subcarriers. These subcarriers are assigned to different users for simultaneous transmission. OFDMA is very sensitive to frequency synchronization errors. In an unsynchronized OFDMA uplink, each user has a different carrier frequency offset (CFO) relative to the common uplink receiver. The orthogonality among subcarriers is thus destroyed resulting in multiple access interference as well as self interference. This problem is tackled in this paper by constructing the orthogonal spectral signals that would have been received if all users were frequency synchronized. A generalized OFDMA is described first considering arbitrary subcarrier assignments. A new signal model is formulated to characterize the interference on the generalized OFDMA uplink due to multiuser frequency synchronization errors. Least squares (LS) and minimum mean square error (MMSE) criteria are used to construct the orthogonal spectral signals from one received OFDMA block. An efficient implementation method is developed based on a banded matrix approximation, which is computationally inexpensive and provides good performance.","PeriodicalId":162046,"journal":{"name":"IEEE Global Telecommunications Conference, 2004. GLOBECOM '04.","volume":"146 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114447424","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: 100
Impact of transmit diversity at handsets on the reverse link DS/CDMA system capacity 手机传输分集对反向链路DS/CDMA系统容量的影响
IEEE Global Telecommunications Conference, 2004. GLOBECOM '04. Pub Date : 2004-11-29 DOI: 10.1109/GLOCOM.2004.1379060
K. Bae, Jong-Han Kim, A. Annamakii, W. Tranter, Jeffrey H. Reed
{"title":"Impact of transmit diversity at handsets on the reverse link DS/CDMA system capacity","authors":"K. Bae, Jong-Han Kim, A. Annamakii, W. Tranter, Jeffrey H. Reed","doi":"10.1109/GLOCOM.2004.1379060","DOIUrl":"https://doi.org/10.1109/GLOCOM.2004.1379060","url":null,"abstract":"This article investigates the impact of antenna diversity implementation at both mobile handsets and basestations on the reverse link DS/CDMA capacity in a myriad of fading environments. Our numerical results reveal that transmit diversity implementation at mobile handsets is most beneficial in indoor propagation channels (since only a few significant resolvable multipaths are available) with low order antenna diversity at the base-station and in harsh fading environments.","PeriodicalId":162046,"journal":{"name":"IEEE Global Telecommunications Conference, 2004. GLOBECOM '04.","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117092256","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
Differential amplitude pulse-position modulation for indoor wireless optical channels 室内无线光信道差分幅度脉冲位置调制
IEEE Global Telecommunications Conference, 2004. GLOBECOM '04. Pub Date : 2004-11-29 DOI: 10.1109/GLOCOM.2004.1378313
U. Sethakaset, T. Gulliver
{"title":"Differential amplitude pulse-position modulation for indoor wireless optical channels","authors":"U. Sethakaset, T. Gulliver","doi":"10.1109/GLOCOM.2004.1378313","DOIUrl":"https://doi.org/10.1109/GLOCOM.2004.1378313","url":null,"abstract":"We propose a novel differential amplitude pulse-position modulation (DAPPM) for indoor optical wireless communications. We present the symbol structure and the properties of DAPPM. The power spectral density of DAPPM is also derived and compared to other modulation schemes. DAPPM yields advantages over PPM and DPPM in terms of bandwidth efficiency, capacity and peak-to-average power ratio (PAPR). The power efficiency is also examined. Over a non-dispersive channel, DAPPM gives better bandwidth and/or power efficiency depending on the number of amplitude levels (A) and the maximum length (L) of a symbol. We also show that, over a dispersive channel, DAPPM has better bandwidth efficiency but requires more power than PPM and DPPM for the same value of L.","PeriodicalId":162046,"journal":{"name":"IEEE Global Telecommunications Conference, 2004. GLOBECOM '04.","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129746267","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: 16
Monte Carlo sampling based in-home location tracking with minimal RF infrastructure requirements 基于蒙特卡罗采样的家庭位置跟踪，射频基础设施要求最低
IEEE Global Telecommunications Conference, 2004. GLOBECOM '04. Pub Date : 2004-11-29 DOI: 10.1109/GLOCOM.2004.1379045
G. Záruba, M. Huber, Farhad A. Karnangar, Imrich Chlarntac
{"title":"Monte Carlo sampling based in-home location tracking with minimal RF infrastructure requirements","authors":"G. Záruba, M. Huber, Farhad A. Karnangar, Imrich Chlarntac","doi":"10.1109/GLOCOM.2004.1379045","DOIUrl":"https://doi.org/10.1109/GLOCOM.2004.1379045","url":null,"abstract":"The paper describes research towards a system for locating users in a home environment requiring only a minimal wireless infrastructure. The only sensor reading used for the location estimation is the radiofrequency received signal strength indication (RSSI) measured by an RF interface (e.g., Wi-Fi). Location estimates are computed using Bayesian filtering on sample sets derived by Monte Carlo sampling. Wireless signal strength maps for the filter are obtained by a two-step parametric and measurement driven ray-tracing approach to account for absorption and reflection characteristics of various obstacles. Our trace driven simulations indicate that RSSI readings from a single access point in an indoor environment are sufficient to derive good location estimates of users.","PeriodicalId":162046,"journal":{"name":"IEEE Global Telecommunications Conference, 2004. GLOBECOM '04.","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129762516","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: 32
Performance of HARQ and the effect of imperfect power control in CDMA reverse link 码分多址反向链路中HARQ的性能及不完全功率控制的影响
IEEE Global Telecommunications Conference, 2004. GLOBECOM '04. Pub Date : 2004-11-29 DOI: 10.1109/GLOCOM.2004.1378906
Younsun Kim, Jin-Kyu Han, Hwanjoon Kwon, Donghee Kim
{"title":"Performance of HARQ and the effect of imperfect power control in CDMA reverse link","authors":"Younsun Kim, Jin-Kyu Han, Hwanjoon Kwon, Donghee Kim","doi":"10.1109/GLOCOM.2004.1378906","DOIUrl":"https://doi.org/10.1109/GLOCOM.2004.1378906","url":null,"abstract":"The paper evaluates the performance of hybrid automatic repeat request (HARQ) for the code division multiple access (CDMA) reverse link in a power controlled scenario and assesses the effect of imperfect power control on HARQ. Analytical results on the performance of HARQ and the effect of imperfect power control are derived and verified using simulation in Rayleigh and Rician fading channels. Results show that HARQ provides robustness against imperfect power control.","PeriodicalId":162046,"journal":{"name":"IEEE Global Telecommunications Conference, 2004. GLOBECOM '04.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128471186","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: 5
A centralized key management scheme for hierarchical access control 用于分层访问控制的集中密钥管理方案
IEEE Global Telecommunications Conference, 2004. GLOBECOM '04. Pub Date : 2004-11-29 DOI: 10.1109/GLOCOM.2004.1378375
Qiong Zhang, Yuke Wang
{"title":"A centralized key management scheme for hierarchical access control","authors":"Qiong Zhang, Yuke Wang","doi":"10.1109/GLOCOM.2004.1378375","DOIUrl":"https://doi.org/10.1109/GLOCOM.2004.1378375","url":null,"abstract":"Key management schemes are used to provide access control to data streams for legitimate users. The users often have certain partially ordered relations, while data streams also form some partially ordered relations. Previous key management schemes have failed to take into consideration either the user relations or data stream relations. We propose a centralized key management scheme for hierarchical access control that considers both partially ordered users and partially ordered data streams. Our scheme improves the efficiency of key management by encrypting multiple equivalent data streams with a single data encryption key, instead of encrypting each data stream with a unique data encryption key in the multi-group key management scheme (Sun, Y. and Ray Liu, K.J., IEEE INFOCOM, 2004). We develop a simulation model to evaluate the performance of our proposed scheme. Simulation results show that our scheme reduces at least 20% of storage overhead at every user and rekey overhead compared to the multi-group key management scheme.","PeriodicalId":162046,"journal":{"name":"IEEE Global Telecommunications Conference, 2004. GLOBECOM '04.","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128738612","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: 71
Using k-nearest neighbor method to identify poison message failure 利用k-最近邻方法识别有毒信息故障
IEEE Global Telecommunications Conference, 2004. GLOBECOM '04. Pub Date : 2004-11-29 DOI: 10.1109/GLOCOM.2004.1378384
Xiaojiang Du
{"title":"Using k-nearest neighbor method to identify poison message failure","authors":"Xiaojiang Du","doi":"10.1109/GLOCOM.2004.1378384","DOIUrl":"https://doi.org/10.1109/GLOCOM.2004.1378384","url":null,"abstract":"Poison message failure is a mechanism that has been responsible for large scale failures in both telecommunications and IP networks. The poison message failure can propagate in the network and cause an unstable network. We apply a machine learning, data mining technique in the network fault management area. We use the k-nearest neighbor method to identity the poison message failure. We also propose a \"probabilistic\" k-nearest neighbor method which outputs a probability distribution about the poison message. Through extensive simulations, we show that the k-nearest neighbor method is very effective in identifying the responsible message type.","PeriodicalId":162046,"journal":{"name":"IEEE Global Telecommunications Conference, 2004. GLOBECOM '04.","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128610935","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
Pilot power ratio design for hierarchical CDMA systems in supporting multi-class services 支持多类业务的分层CDMA系统导频功率比设计
IEEE Global Telecommunications Conference, 2004. GLOBECOM '04. Pub Date : 2004-11-29 DOI: 10.1109/GLOCOM.2004.1378085
Li-Chun Wang, S. Cheng
{"title":"Pilot power ratio design for hierarchical CDMA systems in supporting multi-class services","authors":"Li-Chun Wang, S. Cheng","doi":"10.1109/GLOCOM.2004.1378085","DOIUrl":"https://doi.org/10.1109/GLOCOM.2004.1378085","url":null,"abstract":"Multi-class services change the design paradigm and pose new challenges for future wireless networks. In the future, a voice-oriented macrocell and a data-oriented microcell will co-exist to support multi-class services. In this paper, we develop an analytical framework to determine the optimal pilot power ratio for the CDMA system considering the impact of hierarchical cellular structure, cochannel interference, shadowing, and multi-class service requirements. An analytical approach for determining the pilot power in the hierarchical cellular system is developed to maximize system capacity in supporting multi-class traffic. Based on this analytical approach, we find that to maximize the system capacity, it is necessary to increase the pilot power of the microcell, but lower the pilot power of the macrocell.","PeriodicalId":162046,"journal":{"name":"IEEE Global Telecommunications Conference, 2004. GLOBECOM '04.","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129365139","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
Performance analysis of line strip multispot diffusing system, fully diffuse, and hybrid optical wireless techniques in a real environment 线带多点漫射系统、全漫射和混合光无线技术在真实环境中的性能分析
IEEE Global Telecommunications Conference, 2004. GLOBECOM '04. Pub Date : 2004-11-29 DOI: 10.1109/GLOCOM.2004.1378148
A. Al-Ghamdi, J. Elmirghani
{"title":"Performance analysis of line strip multispot diffusing system, fully diffuse, and hybrid optical wireless techniques in a real environment","authors":"A. Al-Ghamdi, J. Elmirghani","doi":"10.1109/GLOCOM.2004.1378148","DOIUrl":"https://doi.org/10.1109/GLOCOM.2004.1378148","url":null,"abstract":"Performance comparison and evaluations for indoor optical wireless systems in three different environments are carried out. Channel characteristics of infrared links have been evaluated under various conditions including an empty room, a room with glass windows and a door, and a room that has very strong shadowing effects caused by mini cubical offices. The corresponding results have been analyzed and compared for conventional hybrid/diffuse systems (CDS/CHS) and line strip multibeam transmitter systems (LSMS) that use spot diffusing techniques. Eight directive lamps represented the ambient light noise and allowed further signal impairments to be taken into account. Under these conditions, our results indicate that LSMS can reduce pulse spread by a factor of 11 and 30 lower than the delay spread associated with CDS and CHS respectively. Furthermore, LSMS links can increase the SNR by more than 50 dB and about 55 dB compared to the CDS and CHS respectively.","PeriodicalId":162046,"journal":{"name":"IEEE Global Telecommunications Conference, 2004. GLOBECOM '04.","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129077803","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: 6
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