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Proceedings IEEE 56th Vehicular Technology Conference最新文献

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Improved iterative channel estimation and turbo decoding over flat-fading channels 改进的迭代信道估计和turbo解码在平衰落信道
Proceedings IEEE 56th Vehicular Technology Conference Pub Date : 2002-12-10 DOI: 10.1109/VETECF.2002.1040746
B. Mielczarek, A. Svensson
{"title":"Improved iterative channel estimation and turbo decoding over flat-fading channels","authors":"B. Mielczarek, A. Svensson","doi":"10.1109/VETECF.2002.1040746","DOIUrl":"https://doi.org/10.1109/VETECF.2002.1040746","url":null,"abstract":"In this paper, we discuss the influence of imperfect Wiener channel estimation on performance and dynamics of a turbo decoder using nonlinear soft data feedback. We show that the correlation between the channel estimates and soft bits produced in subsequent iterations can lock the turbo decoder in a wrong minimum and create a high error floor. This problem can be circumvented by a different way of estimating code symbols used to improve the synchronization of the signal. An enhanced version of the channel estimator using Wiener filtering of the initial pilot symbols, followed by a modified Viterbi decoder and turbo decoder is shown to improve the system's performance by around 0.5 dB in the waterfall region and to considerably lower the error floor.","PeriodicalId":162055,"journal":{"name":"Proceedings IEEE 56th Vehicular Technology Conference","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125109583","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
Adaptive filterbank multicarrier wireless systems for indoor environments 室内环境自适应滤波器组多载波无线系统
Proceedings IEEE 56th Vehicular Technology Conference Pub Date : 2002-12-10 DOI: 10.1109/VETECF.2002.1040360
A. Wyglinski, P. Kabal, F. Labeau
{"title":"Adaptive filterbank multicarrier wireless systems for indoor environments","authors":"A. Wyglinski, P. Kabal, F. Labeau","doi":"10.1109/VETECF.2002.1040360","DOIUrl":"https://doi.org/10.1109/VETECF.2002.1040360","url":null,"abstract":"We investigate the use of modulated filterbanks in adaptive wireless multicarrier systems operating in indoor environments. The motivation for using filterbanks, as opposed to OFDM, is that these spectrally selective modulation filters can decrease the amount of interchannel interference without using lengthy cyclic prefixes which are necessary in OFDM. The design of the synthesis and analysis filterbanks, based on a single lowpass prototype filter, is presented. Furthermore, optimal subcarrier MMSE equalization, adaptive bit and power loading, as well as null subcarrier placement techniques are employed to enhance system throughput and bit error rate performance when operating in frequency selective channels. The performance of this system is studied and compared with an IEEE 802.11a compliant system, which is based upon OFDM modulation.","PeriodicalId":162055,"journal":{"name":"Proceedings IEEE 56th Vehicular Technology Conference","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129537373","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
Variable rate space-time trellis codes 可变速率时空网格代码
Proceedings IEEE 56th Vehicular Technology Conference Pub Date : 2002-12-10 DOI: 10.1109/VETECF.2002.1040374
Z. Safar, K. Liu
{"title":"Variable rate space-time trellis codes","authors":"Z. Safar, K. Liu","doi":"10.1109/VETECF.2002.1040374","DOIUrl":"https://doi.org/10.1109/VETECF.2002.1040374","url":null,"abstract":"Emerging wireless applications have created a strong motivation to increase the throughput of wireless communication systems. Space-time coding has become a promising method to achieve high data rates. We propose a space-time trellis code construction method that can provide variable protection against the adverse effects of the radio channel. The method is based on the multiple trellis coded modulation construction: the variable data protection is realized by changing the number of output symbols per state transition. The simulation results show the achievable tradeoffs between spectral efficiency, diversity and decoding complexity.","PeriodicalId":162055,"journal":{"name":"Proceedings IEEE 56th Vehicular Technology Conference","volume":"264 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129136501","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
The blocking characteristics of receiver in W-CDMA system W-CDMA系统中接收机的阻塞特性
Proceedings IEEE 56th Vehicular Technology Conference Pub Date : 2002-12-10 DOI: 10.1109/VETECF.2002.1040612
Dong Han Lee, I. Lee, Sanggee Kang
{"title":"The blocking characteristics of receiver in W-CDMA system","authors":"Dong Han Lee, I. Lee, Sanggee Kang","doi":"10.1109/VETECF.2002.1040612","DOIUrl":"https://doi.org/10.1109/VETECF.2002.1040612","url":null,"abstract":"The paper reports progress in current work at ETRI (Electronics and Telecommunications Research Institute, Korea) having the objective of verifying a standard test platform (STP) and developing the post-commercial hardware for W-CDMA systems. For many receivers, the single sideband (SSB) phase noise of the signal generator used to produce the interfering signal is a critical spectral characteristic. If the phase noise energy inside the passband of the IF filter is excessive, the receiver may appear to fail the test. So, we focus on the conformance test and results for the blocking characteristics of a receiver in a W-CDMA system based on 3GPP TS 25.141 and suggest some methods for exact measurement of the blocking test.","PeriodicalId":162055,"journal":{"name":"Proceedings IEEE 56th Vehicular Technology Conference","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130592936","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
A class of switching turbo decoders against severe SNR mismatch 一类针对严重信噪比不匹配的开关涡轮解码器
Proceedings IEEE 56th Vehicular Technology Conference Pub Date : 2002-12-10 DOI: 10.1109/VETECF.2002.1040609
C. Kei, W. Mow
{"title":"A class of switching turbo decoders against severe SNR mismatch","authors":"C. Kei, W. Mow","doi":"10.1109/VETECF.2002.1040609","DOIUrl":"https://doi.org/10.1109/VETECF.2002.1040609","url":null,"abstract":"In mobile communication applications, the fading channel characteristics may vary very rapidly, resulting in a severe SNR mismatch in the receiver. On one hand, the performance of Log-MAP-based turbo decoder degrades significantly in the presence of large SNR underestimation errors. On the other hand, the very robust Max-Log-MAP-based turbo decoder has a SNR loss of about 0.5 dB relative to the former decoder in the absence of SNR mismatch. In this work, we propose a class of switching turbo decoders each specified by a parameter S, which can be selected to compromise the performance without SNR mismatch for the robustness against severe SNR mismatch. Our simulation results demonstrate that by choosing a proper value of S, it is possible to obtain a switching turbo decoder which is not only robust against severe SNR mismatch but also performs reasonably well compared to the Log-MAP-based turbo decoder without SNR mismatch. In addition, the switching operation can be easily implemented by turning off all the correction term related operations in the Log-MAP component decoder. In order to further increase the robustness of the decoder, an auto-switching decoder is also proposed, which will automatically switch from Log-MAP to MAX-Log-MAP. Finally, it is anticipated that the proposed scheme can be fruitfully applied to the serial concatenated convolutional codes, which are even more sensitive to SNR mismatch than the turbo codes.","PeriodicalId":162055,"journal":{"name":"Proceedings IEEE 56th Vehicular Technology Conference","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123973635","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
Joint capacity and quality evaluation for AMR telephony speech in WCDMA systems WCDMA系统中AMR电话语音的联合容量和质量评价
Proceedings IEEE 56th Vehicular Technology Conference Pub Date : 2002-12-10 DOI: 10.1109/VETECF.2002.1040578
M. Karlsson, M. Almgren, S. Bruhn, K. Larsson, M. Sundelin
{"title":"Joint capacity and quality evaluation for AMR telephony speech in WCDMA systems","authors":"M. Karlsson, M. Almgren, S. Bruhn, K. Larsson, M. Sundelin","doi":"10.1109/VETECF.2002.1040578","DOIUrl":"https://doi.org/10.1109/VETECF.2002.1040578","url":null,"abstract":"The adaptive multi-rate (AMR) speech codec is the mandatory speech codec for WCDMA systems. The codec supports eight different source rates ranging from 12.2 kbit/s down to 4.75 kbit/s. This paper evaluates different ways of allocating AMR rates to users on the downlink in a WCDMA system. A novel system performance concept is introduced based on a user satisfaction metric that tries to combine the user experience from different speech quality levels as well as events like blocking and dropping. System simulations show that the AMR codec introduces a significant trade-off between capacity and quality for the speech service. By allocating AMR modes based on the system load, the quality and capacity trade-off can be efficiently balanced and high system performance can be achieved for a wide range of offered loads.","PeriodicalId":162055,"journal":{"name":"Proceedings IEEE 56th Vehicular Technology Conference","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123369018","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
Link capacity analysis for virtual antenna arrays 虚拟天线阵列链路容量分析
Proceedings IEEE 56th Vehicular Technology Conference Pub Date : 2002-12-10 DOI: 10.1109/VETECF.2002.1040381
M. Dohler, J. Dominguez, H. Aghvami
{"title":"Link capacity analysis for virtual antenna arrays","authors":"M. Dohler, J. Dominguez, H. Aghvami","doi":"10.1109/VETECF.2002.1040381","DOIUrl":"https://doi.org/10.1109/VETECF.2002.1040381","url":null,"abstract":"The previously introduced concept of virtual antenna arrays (VAA) promises a significant increase in link and system capacity. These therefore constitute a promising candidate for ad-hoc oriented 4G networks. VAA successfully emulates a multiple-input-multiple-output (MIMO) transmission channel to which space-time codes (STC) can be applied. The realisation of VAA is accomplished by letting spatially close mobile terminals communicate with each other, which overcomes the disadvantage of having only one receiving antenna in a mobile handset. The thus created ad-hoc network represents a general form of MIMO channels for which a new approach to link capacity calculation is required. The work presented establishes some fundamental tenets for the calculation of link capacity in the Shannon sense to ad-hoc networks, such as VAA. It shows that the capacity drastically increases over a network where each terminal maintains a single link to the base station. The results are somewhat preliminary since VAA constitutes only a minor subset of possible ad-hoc network configurations.","PeriodicalId":162055,"journal":{"name":"Proceedings IEEE 56th Vehicular Technology Conference","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123369460","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: 73
The impact of channel estimation error on space-time block codes 信道估计误差对空时分组码的影响
Proceedings IEEE 56th Vehicular Technology Conference Pub Date : 2002-12-10 DOI: 10.1109/VETECF.2002.1040551
R. Buehrer, N. Kumar
{"title":"The impact of channel estimation error on space-time block codes","authors":"R. Buehrer, N. Kumar","doi":"10.1109/VETECF.2002.1040551","DOIUrl":"https://doi.org/10.1109/VETECF.2002.1040551","url":null,"abstract":"We examine the impact of channel estimation error on the performance of 2 and 4 antenna space-time block codes. This is examined specifically in the context of space-time spreading as defined for the cdma2000 standard. The performance is determined by finding an expression for the probability of bit error when using BPSK or QPSK modulation and modeling the channel estimation error as a Gaussian random variable.","PeriodicalId":162055,"journal":{"name":"Proceedings IEEE 56th Vehicular Technology Conference","volume":"90 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123491338","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: 36
Performance evaluation of space-time-frequency block codes over frequency selective fading channels 空时频分组码在频率选择性衰落信道上的性能评价
Proceedings IEEE 56th Vehicular Technology Conference Pub Date : 2002-12-10 DOI: 10.1109/VETECF.2002.1040459
K. Suto, T. Ohtsuki
{"title":"Performance evaluation of space-time-frequency block codes over frequency selective fading channels","authors":"K. Suto, T. Ohtsuki","doi":"10.1109/VETECF.2002.1040459","DOIUrl":"https://doi.org/10.1109/VETECF.2002.1040459","url":null,"abstract":"Space-time block coded OFDM (ST-OFDM) has been proposed as an attractive solution for a high bit rate data transmission in a multipath fading environment. Space-frequency block coded OFDM (SF-OFDM) has been also proposed as another solution. These two systems utilize the STBC with the 2/spl times/2 transmission matrix, using two transmit antennas. If we apply the STBC with the 4/spl times/4 transmission matrix to OFDM, using four transmit antennas, we can expect the performance improvement. In addition, applying the STBC with the 4/spl times/4 transmission matrix to OFDM, we can form block codes over the space, time, and frequency domains, that is, we can implement the space-time-frequency block coded OFDM (STF-OFDM). In this paper, we apply the STBC with the 4/spl times/4 transmission matrix to OFDM and compare the performance of the three systems (ST-OFDM, SF-OFDM, STF-OFDM). We show that the best system with respect to the error rate performance differs in the different channel conditions.","PeriodicalId":162055,"journal":{"name":"Proceedings IEEE 56th Vehicular Technology Conference","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121293149","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: 43
Propagation-measurement-based predictions of RAKE receiver performance in W-CDMA systems operating in urban microcells 基于传播测量的城市微蜂窝W-CDMA系统RAKE接收机性能预测
Proceedings IEEE 56th Vehicular Technology Conference Pub Date : 2002-12-10 DOI: 10.1109/VETECF.2002.1040314
N. Adnani, R. Bultitude, R. Hafez
{"title":"Propagation-measurement-based predictions of RAKE receiver performance in W-CDMA systems operating in urban microcells","authors":"N. Adnani, R. Bultitude, R. Hafez","doi":"10.1109/VETECF.2002.1040314","DOIUrl":"https://doi.org/10.1109/VETECF.2002.1040314","url":null,"abstract":"A service specification of third generation wireless systems using wideband CDMA is to enable the delivery of data rates up to 2 Mbps to a single user on the downlink channel. One implication of such high data rates is the reduction of spreading gain, which results in increased multiple-access interference and also self-interference (SI). The latter is the result of multipath propagation and the imperfect autocorrelation properties of the spreading sequences that must be used for despreading. SI is estimated using a semi-analytical approach when the number of distinct multipath groups, each the vector sum of all multipath signals received within the delay resolution of the receiver, and their strengths are estimated using measured data. This in turn is used to predict bit error rates as a function of signal-to-noise ratio when a RAKE receiver is used in a mobile terminal.","PeriodicalId":162055,"journal":{"name":"Proceedings IEEE 56th Vehicular Technology Conference","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114224267","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
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