European Transactions on Telecommunications最新文献

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Joint EM channel and covariance estimation with sufficient-statistic chip combining for a SIMO MC-CDMA anti-jam system SIMO MC-CDMA抗干扰系统的联合电磁信道和充分统计芯片组合的协方差估计
European Transactions on Telecommunications Pub Date : 2010-06-18 DOI: 10.1002/ett.1425
M. Asadullah, Gordon L. Stüber
{"title":"Joint EM channel and covariance estimation with sufficient-statistic chip combining for a SIMO MC-CDMA anti-jam system","authors":"M. Asadullah, Gordon L. Stüber","doi":"10.1002/ett.1425","DOIUrl":"https://doi.org/10.1002/ett.1425","url":null,"abstract":"Joint iterative channel and covariance estimation with sufficient-statistic-based chip combining is studied for the downlink of a multicarrier code division multiple access (MC-CDMA) system operating under partial-band noise jamming (PBNJ). To estimate the channel and AWGN-plus-PBNJ covariance, we apply the expectation-maximisation (EM) algorithm which exploits the log-likelihood ratio (LLR) from the decoder. The proposed chip combiner guarantees no loss of information in the soft output generated by the demapper. In our approach, the channel estimator or the chip combiner only requires the AWGN-plus-PBNJ power of each subcarrier to suppress jamming. Therefore, significant complexity reduction is achieved because the receiver does not need to estimate the jammer state information (JSI) and individual variances of the AWGN and PBNJ on each subcarrier for chip combining. Simulation results show that the sufficient-statistic chip combiner always offers a smaller bit error rate (BER) than the minimum mean square error (MMSE) chip combiner provided that reliable estimates of the channel impulse response and noise-plus-jamming covariance are available. Copyright © 2010 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"170 1","pages":"409-416"},"PeriodicalIF":0.0,"publicationDate":"2010-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84004519","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
PAPR reduction technique using pilot symbols for OFDM systems OFDM系统中使用导频符号的PAPR降低技术
European Transactions on Telecommunications Pub Date : 2010-06-18 DOI: 10.1002/ETT.1423
I. M. Mahafeno, Y. Louët, J. Hélard, Y. Nasser, A. Ho
{"title":"PAPR reduction technique using pilot symbols for OFDM systems","authors":"I. M. Mahafeno, Y. Louët, J. Hélard, Y. Nasser, A. Ho","doi":"10.1002/ETT.1423","DOIUrl":"https://doi.org/10.1002/ETT.1423","url":null,"abstract":"High peak-to-average power ratio (PAPR) is a critical issue in any orthogonal frequency division multiplexing (OFDM) system, such as digital video broadcasting (DVB). Due to the nonlinearity of high power amplifier (HPA), it can result in low power efficiency and performance degradation of systems. In this paper, a tone reservation (TR) approach for PAPR reduction in OFDM systems is proposed by using pilot subcarriers simultaneously for PAPR reduction and channel estimation. At the receiver, a blind detection which avoids sending any side information (SI) is performed. The proposed approach improves the system spectral efficiency compared to the regular TR method that uses a set of useful subcarriers for PAPR reduction only. Simulation results using the current DVB-T2 parameters demonstrate its relevance for future DVB systems.† Copyright © 2010 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"50 1","pages":"435-442"},"PeriodicalIF":0.0,"publicationDate":"2010-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78268107","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
Comparison of different channel estimation approaches for Block-IFDMA Block-IFDMA不同信道估计方法的比较
European Transactions on Telecommunications Pub Date : 2010-06-08 DOI: 10.1002/ett.1427
Anja Sohl, A. Klein
{"title":"Comparison of different channel estimation approaches for Block-IFDMA","authors":"Anja Sohl, A. Klein","doi":"10.1002/ett.1427","DOIUrl":"https://doi.org/10.1002/ett.1427","url":null,"abstract":"SUMMARY In this paper, channel estimation for Discrete Fourier Transform (DFT) precoded Orthogonal Frequency Division Multiple Access (OFDMA) with block-interleaved subcarrier allocation per user, which is denoted as Block-Interleaved Frequency Division Multiple Access (B-IFDMA), is considered. Recent investigations are presented for new pilot insertion methods which exhibit different impact on the Peak-to-Average Power Ratio (PAPR) of the transmit signal and offer different possibilities of positioning the pilots in frequency domain. Each of these pilot insertion methods is combined with a corresponding algorithm to estimate the Channel Variations in Frequency Domain (CVFD). The Channel Variations in Time Domain (CVTD) are estimated by an improved Decision Directed Channel Estimation (DDCE) with joint iterative Wiener filtering which reduces the error propagation by considering certain neighbouring symbols jointly in each iteration step. The DDCE is compared to a Wiener interpolation filter for the estimation of CVTD. The combinations of pilot insertion method, estimation algorithm for CVFD and CVTD are compared in terms of the PAPR and the Mean Square Error (MSE) performance. Thereby, the impact of different pilot positions in frequency domain and time domain is investigated. Copyright © 2010 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"38 1","pages":"417-425"},"PeriodicalIF":0.0,"publicationDate":"2010-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81244052","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
Communication Networks Survivable routing algorithm with mixed shared protection in fault-tolerant GMPLS multi-layered optical networks 容错GMPLS多层光网络中混合共享保护的通信网络生存性路由算法
European Transactions on Telecommunications Pub Date : 2010-06-01 DOI: 10.1002/ETT.1409
Lei Guo, Jiannong Cao, Xingwei Wang, Xuetao Wei, Qiming Gai, Zhaolong Ning, Cunqian Yu
{"title":"Communication Networks Survivable routing algorithm with mixed shared protection in fault-tolerant GMPLS multi-layered optical networks","authors":"Lei Guo, Jiannong Cao, Xingwei Wang, Xuetao Wei, Qiming Gai, Zhaolong Ning, Cunqian Yu","doi":"10.1002/ETT.1409","DOIUrl":"https://doi.org/10.1002/ETT.1409","url":null,"abstract":"In this paper, we studied survivability in general multi-protocol label switching (GMPLS) multi-layered optical networks and proposed a novel mixed shared protection algorithm (MSPA) based on the integrated layered graph (ILG) to tolerate single-fibre link failure. The ILG is composed of one virtual topology layer (VTL), corresponding to IP/MPLS layer; multiple wavelength-plane layers (WPLs), corresponding to the wavelength-division multiplexing (WDM) optical layer; and some virtual links that connect the VTL to each WPL in order to solve the problem on routing, wavelength assignment and low-speed traffic grooming. For every connection request, the MSPA first computes a single-hop or multi-hop label switching path (LSP) pair, involving a working LSP and a physical link-disjoint backup LSP in the VTL. If the LSP pair is not found in the VTL, the MSPA computes the new LSP pair in the WPL. Conversely, if the new LSP pair is not detected in the WPL, the MSPA computes the hybrid multi-hop LSP pair in the ILG. In the MSPA, if the two working LSPs are in physical link-disjoint, their corresponding backup LSPs can share the backup bandwidth. In addition, the working LSPs and the backup LSPs can also share the same mixed of wavelength, in which the different bandwidths can be assigned to different working and backup LSPs. Simulation results show that, compared to previous algorithm, the MSPA can obtain a better bandwidth utilisation ratio (BUR) with a lower blocking probability. Copyright © 2010 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"76 1","pages":"312-323"},"PeriodicalIF":0.0,"publicationDate":"2010-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83861638","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
Information Theory Capacity of the two-way relay channel within a constant gap 信息论在一定间隙内双向中继信道的容量
European Transactions on Telecommunications Pub Date : 2010-06-01 DOI: 10.1002/ett.1399
A. Avestimehr, A. Sezgin, David Tse
{"title":"Information Theory Capacity of the two-way relay channel within a constant gap","authors":"A. Avestimehr, A. Sezgin, David Tse","doi":"10.1002/ett.1399","DOIUrl":"https://doi.org/10.1002/ett.1399","url":null,"abstract":"SUMMARY We study the capacity of the full-duplex bidirectional (or t wo-way) relay channel with two nodes and one relay. The channels in the forward direction are assumed to be different (in general) than the channels in the backward direction, i.e. channel reciprocity is not ass umed. We use the recently proposed deterministic approach to capture the essence of the problem and to determine a good transmission and relay strategy for the Gaussian channel. Depending on the ratio of the individual channel gains, we propose to use either a simple amplify-and-forward or a particular superposition coding strategy at the relay. We analyze the achievable rate region and show that the scheme achieves to within 3 bits the cut-set bound for all values of channel gains. Copyright c 0000 AEIT","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"50 1","pages":"363-374"},"PeriodicalIF":0.0,"publicationDate":"2010-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79943706","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: 96
Communication Theory Transforming the distribution of OFDM signals for peak-to-average power ratio reduction 通信理论变换OFDM信号的分布以降低峰均功率比
European Transactions on Telecommunications Pub Date : 2010-06-01 DOI: 10.1002/ett.1395
Xiaodong Zhu, Guangxi Zhu, Pei Lin
{"title":"Communication Theory Transforming the distribution of OFDM signals for peak-to-average power ratio reduction","authors":"Xiaodong Zhu, Guangxi Zhu, Pei Lin","doi":"10.1002/ett.1395","DOIUrl":"https://doi.org/10.1002/ett.1395","url":null,"abstract":"Large peak-to-average power ratio (PAPR) is the main drawback of orthogonal frequency division multiplexing (OFDM) systems. In this paper, a novel nonlinear scheme is proposed to reduce the PAPR. This scheme transforms the amplitude of original OFDM signals from Rayleigh distribution into beta distribution. Moreover, given different parameters, this scheme has different transformation expressions. It is demonstrated that the well-known companding schemes based on exponential function and error function are actually the special cases of the proposed scheme. Further, we derive another simpler expression of the proposed scheme. Simulation results show that the new transformation can achieve a better tradeoff between PAPR reduction and bit-error rate (BER) performance than the exponential function and error function companding schemes. Copyright © 2010 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"46 1","pages":"352-362"},"PeriodicalIF":0.0,"publicationDate":"2010-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80002309","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: 15
Communication Networks Opportunistic multiuser scheduling with reduced feedback load 通信网络减少反馈负载的机会多用户调度
European Transactions on Telecommunications Pub Date : 2010-06-01 DOI: 10.1002/ett.1403
Y. Al-Harthi
{"title":"Communication Networks Opportunistic multiuser scheduling with reduced feedback load","authors":"Y. Al-Harthi","doi":"10.1002/ett.1403","DOIUrl":"https://doi.org/10.1002/ett.1403","url":null,"abstract":"In this paper, we propose a reduced feedback opportunistic scheduling (RFOS) algorithm that reduces the feedback load while preserving the performance of opportunistic scheduling (OS). The RFOS algorithm is a modified version of our previously proposed algorithm, the DSMUDiv algorithm. The main difference is that RFOS consists of a probing process (search process) and a requesting feedback process based on a threshold. The threshold value is variable, and it depends on the probing process. To reduce the feedback rate, a quantised value indicating the modulation level is fed back, instead of the full value of the signal-to-noise ratio (SNR), which we call quantised SNR. The paper includes the closed-form expressions of the probing load, feedback load and spectral efficiency. In addition, we investigate the effect of the scheduling delay on the system throughput (STH). Under slow Rayleigh fading assumption, we compare RFOS algorithm with the DSMUDiv and optimal (full feedback load) selective diversity scheduling algorithms. Copyright © 2010 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"21 1","pages":"299-311"},"PeriodicalIF":0.0,"publicationDate":"2010-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81521529","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
Wireless Systems A simplified MAP channel estimator for OFDM systems under Rayleigh fading 无线系统瑞利衰落下OFDM系统的一种简化MAP信道估计器
European Transactions on Telecommunications Pub Date : 2010-06-01 DOI: 10.1002/ett.1415
Selva Muratoğlu Çürük, Y. Tanik
{"title":"Wireless Systems A simplified MAP channel estimator for OFDM systems under Rayleigh fading","authors":"Selva Muratoğlu Çürük, Y. Tanik","doi":"10.1002/ett.1415","DOIUrl":"https://doi.org/10.1002/ett.1415","url":null,"abstract":"This paper presents a simplified Maximum A Posteriori (SMAP) channel estimator to be used in orthogonal frequency division multiplexing (OFDM) systems under the Rayleigh fading assumption for the subchannels, using a parametric correlation model and assuming that the channel is frequency selective and slowly time varying. Expressions for the mean-square error (MSE) of estimations are derived to evaluate the performance of the estimator. The relation between the correlation of subchannels taps and error variance is investigated. Dependencies of the proposed estimator's performance on the correlation parameter estimation error and signal-to-noise ratios (SNR) estimation error are analysed. We provide approximations on the estimator algorithms in order to make the estimator practical. The simulations done using measured channel data show that the proposed estimator with approximations operates satisfactorily with negligible loss in performance. Finally, we investigate the symbol error rate (SER) performance of an OFDM system using quadrature phase-shift keying (QPSK) modulation, based on channel estimation modes (a) training sequence (b) decision feedback and (c) pilot subcarriers. The results have indicated that the proposed estimator performance is always better than maximum likelihood (ML) estimator, and as the subchannel correlation increases (large number of subcarriers) the performance comes very close to that of exactly known channel case. Copyright © 2010 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"52 1","pages":"396-405"},"PeriodicalIF":0.0,"publicationDate":"2010-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73622058","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
Mobile Networks Trust management in wireless sensor networks 无线传感器网络中的信任管理
European Transactions on Telecommunications Pub Date : 2010-06-01 DOI: 10.1002/ett.1413
T. Zahariadis, H. Leligou, P. Trakadas, S. Voliotis
{"title":"Mobile Networks Trust management in wireless sensor networks","authors":"T. Zahariadis, H. Leligou, P. Trakadas, S. Voliotis","doi":"10.1002/ett.1413","DOIUrl":"https://doi.org/10.1002/ett.1413","url":null,"abstract":"SUMMARY The range of applications of wireless sensor networks is so wide that it tends to invade our every day life. In the future, a sensor network will survey our health, our home, the roads we follow, the office or the industry we work in or even the aircrafts we use, in an attempt to enhance our safety. However, the wireless sensor networks themselves are prone to security attacks. The list of security attacks, although already very long, continues to augment impeding the expansion of these networks. The trust management schemes consist of a powerful tool for the detection of unexpected node behaviours (either faulty or malicious). Once misbehaving nodes are detected, their neighbours can use this information to avoid cooperating with them, either for data forwarding, data aggregation or any other cooperative function. A variety of trust models which follow different directions regarding the distribution of measurement functionality, the monitored behaviours and the way measurements are used to calculate/define the node’s trustworthiness has been presented in the literature. In this paper, we survey trust models in an attempt to explore the interplay among the implementation requirements, the resource consumption and the achieved security. Our goal is to draw guidelines for the design of deployable trust model designs with respect to the available node and network capabilities and application peculiarities. Copyright © 2010 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"49 1","pages":"386-395"},"PeriodicalIF":0.0,"publicationDate":"2010-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89980020","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: 114
Selective mapping for reduced complexity turbo channel estimation operating on highly time and frequency selective channels 选择性映射降低复杂性涡轮信道估计操作在高时间和频率选择性信道
European Transactions on Telecommunications Pub Date : 2010-04-08 DOI: 10.1002/ett.1397
Sihem Châabouni, M. Siala, N. Sellami
{"title":"Selective mapping for reduced complexity turbo channel estimation operating on highly time and frequency selective channels","authors":"Sihem Châabouni, M. Siala, N. Sellami","doi":"10.1002/ett.1397","DOIUrl":"https://doi.org/10.1002/ett.1397","url":null,"abstract":"In this paper, we consider a time division multiple access (TDMA) transmission of coded symbols over a time and frequency selective channel. At the receiver, a turbo-detector composed of a maximum a posteriori (MAP) equaliser and a MAP decoder is used. We give the expression of the MAP iterative burst-by-burst channel estimation algorithm using the Expectation-Maximisation (EM) algorithm. Since the obtained algorithm is complex, we propose to simplify it by neglecting the inter-symbol interference (ISI) term. In order to reduce the error caused by this simplification, we propose to use a candidate precoder at the transmitter chosen among a given set of precoders such that the selected precoded sequence leads to the minimum mean square value of the ISI neglected term. Simulations show that the performance of the approximate algorithm with precoding are almost similar to the performance of the exact algorithm. Copyright © 2010 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"83 1","pages":"519-525"},"PeriodicalIF":0.0,"publicationDate":"2010-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81099657","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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