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2008 Fourth Advanced International Conference on Telecommunications最新文献

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Fast Recovery Paths: Reducing Packet Loss Rates during IP Routing Convergence 快速恢复路径:降低IP路由收敛过程中的丢包率
2008 Fourth Advanced International Conference on Telecommunications Pub Date : 2008-06-08 DOI: 10.1109/AICT.2008.21
F. Barreto, E. Wille, L. Nacamura
{"title":"Fast Recovery Paths: Reducing Packet Loss Rates during IP Routing Convergence","authors":"F. Barreto, E. Wille, L. Nacamura","doi":"10.1109/AICT.2008.21","DOIUrl":"https://doi.org/10.1109/AICT.2008.21","url":null,"abstract":"In high speed IP networks, interior gateway protocols, like OSPF, cannot obtain a new route to bypass a failure in time. These protocols' convergence period can vary from hundreds of milliseconds to tens of seconds. During this time there is instability, causing high packet loss rates. This study proposes a proactive approach of fast recovery paths to aid OSPF bypass failures. An evaluation of these paths was conducted, which showed the recovery paths are shorter than other similar approaches and they significantly reduce the packet loss rate during the OSPF convergence period caused by a failure.","PeriodicalId":105735,"journal":{"name":"2008 Fourth Advanced International Conference on Telecommunications","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124493240","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
A New Efficient Convolutional Decoder for GSM Communication Standard with Fuzzy Logic 基于模糊逻辑的GSM通信标准的一种新型高效卷积解码器
2008 Fourth Advanced International Conference on Telecommunications Pub Date : 2008-06-08 DOI: 10.1109/AICT.2008.19
S. Ananthi, K. Visalakshi, S. Rajakumari
{"title":"A New Efficient Convolutional Decoder for GSM Communication Standard with Fuzzy Logic","authors":"S. Ananthi, K. Visalakshi, S. Rajakumari","doi":"10.1109/AICT.2008.19","DOIUrl":"https://doi.org/10.1109/AICT.2008.19","url":null,"abstract":"In GSM communication, one of the aspects is the convolutional encoding of speech data , using a 16 state encoder. Since for every bit, additional v bits are transmitted, there is good scope for error detection and correction. Using state diagram at each time slot, Trellis diagrams are considered as good illustrations for the method of decoding the data and an algorithm by Viterbi is in vogue. Compared to that, the proposed technique is based on the assignment of probability values to the states at all bit timings using certain principles of fuzzy logic. By this, the length limitation of the earlier algorithm is overcome since the memory requirement is only to store the best probable fuzziness values at each time slot and hence faster and code efficient. Comparative illustrations for sample data are given. Further, the method yields the same result of the best possible data accuracy as with the trellis coding. The method has been exhaustively tested for its reliable decoding.","PeriodicalId":105735,"journal":{"name":"2008 Fourth Advanced International Conference on Telecommunications","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121916947","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
Cooperative Diversity with Orthogonal Space Time Coded MSK 正交空时编码MSK的合作分集
2008 Fourth Advanced International Conference on Telecommunications Pub Date : 2008-06-08 DOI: 10.1109/AICT.2008.11
N. Odabasioglu
{"title":"Cooperative Diversity with Orthogonal Space Time Coded MSK","authors":"N. Odabasioglu","doi":"10.1109/AICT.2008.11","DOIUrl":"https://doi.org/10.1109/AICT.2008.11","url":null,"abstract":"Cooperative diversity provides spatial diversity gain via virtual antenna array and thus improves the communication capacity in fading channels. Although space time code (STC) design for continuous phase modulation (CPM) is a new research topic, recent papers illustrated a number of advantages relative to linear modulations such as PSK, QAM etc. In this paper a cooperative diversity system with orthogonal ST coded minimum shift keying (MSK) is introduced. The relay terminal operates both amplify and forward (AF) and decode and forward (DF) modes. Simulation results show that proposed system is very convenient for fading channels since it provides diversity gain and utilizes advantages of continuous phase modulation.","PeriodicalId":105735,"journal":{"name":"2008 Fourth Advanced International Conference on Telecommunications","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130077932","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
Efficient ML Decoder for Quasi-orthogonal Space-Time Codes When Using QAM Constellation QAM星座下准正交空时码的高效ML解码器
2008 Fourth Advanced International Conference on Telecommunications Pub Date : 2008-06-08 DOI: 10.1109/AICT.2008.20
A. Enescu, S. Ciochină, C. Paleologu
{"title":"Efficient ML Decoder for Quasi-orthogonal Space-Time Codes When Using QAM Constellation","authors":"A. Enescu, S. Ciochină, C. Paleologu","doi":"10.1109/AICT.2008.20","DOIUrl":"https://doi.org/10.1109/AICT.2008.20","url":null,"abstract":"The most attractive class of space-time codes comprises the full-rate orthogonal codes, such as the Alamouti code. These codes allow a simple individual decoding of each symbol of the space-time block, leading to a reduced complexity at the receiver. They exist however only for two transmit antennas. If one intends to increase the transmit diversity order, then it may either use a sub-unitary rate orthogonal code or use a full-rate quasi-orthogonal code in which the decoding is done in pairs of symbols. Unfortunately, the pair-wise decoding leads to a large search space of the Maximum Likelihood (ML) decoder, especially for high-rate constellations, such as 16-QAM or 64- QAM. This paper presents a less complex general ML decoding algorithm, with linear pre-processing phase, applicable for a class of quasi-orthogonal space-time codes with rectangular constellations (e.g. QPSK, 16-QAM, 64-QAM).","PeriodicalId":105735,"journal":{"name":"2008 Fourth Advanced International Conference on Telecommunications","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123529417","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
Rogue Access Point Based DoS Attacks against 802.11 WLANs 基于恶意接入点的802.11 wlan DoS攻击
2008 Fourth Advanced International Conference on Telecommunications Pub Date : 2008-06-08 DOI: 10.1109/AICT.2008.54
Chibiao Liu, James T. Yu
{"title":"Rogue Access Point Based DoS Attacks against 802.11 WLANs","authors":"Chibiao Liu, James T. Yu","doi":"10.1109/AICT.2008.54","DOIUrl":"https://doi.org/10.1109/AICT.2008.54","url":null,"abstract":"The growing popularity of the 802.11-based Wireless LAN (WLAN) also increases its risk of security attacks. This paper presents an analysis and solution to two Denial of Service (DoS) attacks: Deauthentication flooding (DeauthF) and disassociation flooding (DisassF) attacks. We conducted experiments to understand the impact of the attacks, and applied the Markov chain model to study the transition probabilities under attacks. We then follow the newly proposed 802.11 w standard and implement a solution to prevent the attacks. Our results show that 802.11 w is effective for low rate deauthentication and disassociation attacks but fails to protect against the flooding attacks because it takes significant resources to authenticate frames. We propose an integrated approach to applying traffic pattern filtering (TPF) over 802.11 w to resolve DeauthF and DisassF DoS attacks. The simulation results yields satisfactory performance for the integrated approach.","PeriodicalId":105735,"journal":{"name":"2008 Fourth Advanced International Conference on Telecommunications","volume":"352 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122843750","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: 28
A Novel Time and Frequency Synchronization Technique for MIMO-OFDM System 一种新的MIMO-OFDM系统时频同步技术
2008 Fourth Advanced International Conference on Telecommunications Pub Date : 2008-06-08 DOI: 10.1109/AICT.2008.53
Xu He, Xiaoyong Peng, Yue Xiao, Shaoqian Li
{"title":"A Novel Time and Frequency Synchronization Technique for MIMO-OFDM System","authors":"Xu He, Xiaoyong Peng, Yue Xiao, Shaoqian Li","doi":"10.1109/AICT.2008.53","DOIUrl":"https://doi.org/10.1109/AICT.2008.53","url":null,"abstract":"In this paper, a novel time and frequency synchronization technique is proposed for an M transmit and P receive (M times P) multiple-input- multiple-output (MIMO) - orthogonal frequency division multiplex (OFDM) system. The proposed technique is based on the assumption that each transmit antenna is with different time delay, which is more important in a practical system. Furthermore, it can be employed in distributed MIMO-OFDM system as well. In the proposed technique, different designed training sequence is proposed for fine time synchronization at each transmit antenna. Furthermore, in the time domain, the combination of all the training sequences can be divided into two identical parts so as to perform coarse time synchronization and carrier frequency offset (CFO) estimation. Simulation results show that the proposed technique can efficiently complete time and frequency in only one OFDM symbol with ideal performance.","PeriodicalId":105735,"journal":{"name":"2008 Fourth Advanced International Conference on Telecommunications","volume":"131 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115808107","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: 14
A General Analytical Method for the Performance Evaluation of Multistage Interconnection Networks Supporting Multi-class Priority Traffic 支持多级优先业务流的多级互联网络性能评价的一般分析方法
2008 Fourth Advanced International Conference on Telecommunications Pub Date : 2008-06-08 DOI: 10.1109/AICT.2008.16
J. Garofalakis, E. Stergiou
{"title":"A General Analytical Method for the Performance Evaluation of Multistage Interconnection Networks Supporting Multi-class Priority Traffic","authors":"J. Garofalakis, E. Stergiou","doi":"10.1109/AICT.2008.16","DOIUrl":"https://doi.org/10.1109/AICT.2008.16","url":null,"abstract":"In this paper, our investigation focuses on the performance evaluation of omega multistage interconnection networks which can natively support multi-class priority traffic. For this reason, a multi- buffered, single server switching element is presented and used in the construction of those networks, providing thus better quality of services. The performance evaluation model is based on steady state queuing analysis that leads to a novel utilization's formula. Based on the proposed analysis, other major performance indicators can also be accurately calculated. The analytical method was meticulously validated by classic simulation and a part of obtained results was also compared by existing related work. Moreover, the proposed analytical method was found to be very accurate on performance estimations for various network sizes under different offered loads supporting multi-priority traffic. The rationale behind investigating a multi-priority traffic system is to provide efficient networks supporting optimum quality of services (i.e. streaming media vs. file transfer).","PeriodicalId":105735,"journal":{"name":"2008 Fourth Advanced International Conference on Telecommunications","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131998503","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
Distributed Optimization Algorithms for X-Domain End-to-End QoS Negotiation x域端到端QoS协商的分布式优化算法
2008 Fourth Advanced International Conference on Telecommunications Pub Date : 2008-06-08 DOI: 10.1109/AICT.2008.48
Ishita Mukhopadhyay, Hélia Pouyllau
{"title":"Distributed Optimization Algorithms for X-Domain End-to-End QoS Negotiation","authors":"Ishita Mukhopadhyay, Hélia Pouyllau","doi":"10.1109/AICT.2008.48","DOIUrl":"https://doi.org/10.1109/AICT.2008.48","url":null,"abstract":"Establishing end-to-end services in X-domain networks is an untrivial problem since it implies to guarantee end-to-end Quality of Service (QoS). The contract approach consisting in designing local QoS contracts (Service Level Agreements, SLAs) seems to be the most adapted approach to achieve this goal. However, due to the independent and heterogenous nature of the Internet domains, the problem may be solved only through a distributed process respecting also the contract privacy. In previous works, we described some distributed optimization algorithms to determine such contract chains. In this paper, we propose an improvement of one of our previous solution. We also give the results of our experiments that lead us to claim that accurate algorithms may be applicable with realistic performances in the X-domain context.","PeriodicalId":105735,"journal":{"name":"2008 Fourth Advanced International Conference on Telecommunications","volume":"226 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123713186","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
Blocking Analysis in Hybrid TDM-WDM PONs Supporting Elastic Traffic 支持弹性业务的TDM-WDM混合PONs阻塞分析
2008 Fourth Advanced International Conference on Telecommunications Pub Date : 2008-06-08 DOI: 10.1109/AICT.2008.76
J. Vardakas, V. Vassilakis, M. Logothetis
{"title":"Blocking Analysis in Hybrid TDM-WDM PONs Supporting Elastic Traffic","authors":"J. Vardakas, V. Vassilakis, M. Logothetis","doi":"10.1109/AICT.2008.76","DOIUrl":"https://doi.org/10.1109/AICT.2008.76","url":null,"abstract":"The passive optical network (PON) is an attractive solution for delivering services with numerous applications, such as high-definition video, video conferencing and data traffic. In this paper we develop teletraffic loss models for calculating connection failure probabilities (due to unavailability of a wavelength) and call blocking probabilities (due to the restricted bandwidth capacity of a wavelength) in hybrid TDM-WDM PONs with dynamic wavelength allocation. We consider either stream or elastic traffic. The proposed models are derived from one-dimensional Markov chains which describe the service system in the PON. The wavelengths occupancy in the PON is also provided. The accuracy of the proposed models is validated by simulation and was found to be quite satisfactory.","PeriodicalId":105735,"journal":{"name":"2008 Fourth Advanced International Conference on Telecommunications","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126745428","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
The Capacity Region for Broadcast Channels with Conditionally Independent Message Sets 条件独立消息集广播信道的容量区域
2008 Fourth Advanced International Conference on Telecommunications Pub Date : 2008-06-08 DOI: 10.1109/AICT.2008.56
G. Hodtani
{"title":"The Capacity Region for Broadcast Channels with Conditionally Independent Message Sets","authors":"G. Hodtani","doi":"10.1109/AICT.2008.56","DOIUrl":"https://doi.org/10.1109/AICT.2008.56","url":null,"abstract":"A more general class of broadcast channels with conditionally independent message sets is defined and its capacity region is determined using Marton 's inner bound and the outer bound considered by Nair and El Gamal. The capacity region for this class of channels includes the capacity region for broadcast channels with degraded message sets, semi-deterministic broadcast channels, deterministic broadcast channels with and without common information, less noisy and (special) more capable broadcast channels.","PeriodicalId":105735,"journal":{"name":"2008 Fourth Advanced International Conference on Telecommunications","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115096925","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
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