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2008 International ITG Workshop on Smart Antennas最新文献

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Improved dual frequency multiple access relay scheme for spatially correlated sources 空间相关源的改进双频多址中继方案
2008 International ITG Workshop on Smart Antennas Pub Date : 2008-03-21 DOI: 10.1109/WSA.2008.4475548
Jose Angel Esteban, J. Ser, P. Crespo, B. Khalaj
{"title":"Improved dual frequency multiple access relay scheme for spatially correlated sources","authors":"Jose Angel Esteban, J. Ser, P. Crespo, B. Khalaj","doi":"10.1109/WSA.2008.4475548","DOIUrl":"https://doi.org/10.1109/WSA.2008.4475548","url":null,"abstract":"We consider the non-cooperative multiple access relay channel, where N users transmit their information to a common receiver with the assistance of a shared relay. For N = 2 independent sources and dual-frequency operation (i.e., two separate frequency channels are available for transmission), it has been recently shown that additional diversity gain can be attained by simply switching the transmit frequency bands between users at the relay site, thus reducing the scenario to a 2times2 MIMO channel with achievable diversity order equal to 2. In this paper we propose to extend this previous work to the case where the sources are spatially correlated. Under a detect-and-forward (DF) relay approach, and using a maximum likelihood (ML) detector, we show that the performance of the aforementioned dual-frequency scheme can be enhanced by preprocessing the detected symbols and properly designing the constellation mapping at the relay site. In addition, we derive closed-form expressions for the symbol error probability of our proposed scheme. Simulation results show that our system outperforms the scheme in when the relay is close to the sources.","PeriodicalId":255495,"journal":{"name":"2008 International ITG Workshop on Smart Antennas","volume":"204 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116358203","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
Comparison of partial transmit sequences and selected mapping for peak-to-average power ratio reduction in MIMO OFDM MIMO OFDM中降低峰均功率比的部分发射序列与选择映射的比较
2008 International ITG Workshop on Smart Antennas Pub Date : 2008-03-21 DOI: 10.1109/WSA.2008.4475577
C. Siegl, R. Fischer
{"title":"Comparison of partial transmit sequences and selected mapping for peak-to-average power ratio reduction in MIMO OFDM","authors":"C. Siegl, R. Fischer","doi":"10.1109/WSA.2008.4475577","DOIUrl":"https://doi.org/10.1109/WSA.2008.4475577","url":null,"abstract":"Multicarrier systems suffer from a high peak-to-average power ratio (PAR) of their transmit signal as large signal peaks lead to power inefficiency of the amplifiers. This issue becomes even more serious in a multi-antenna transmitter. To increase power efficiency, a PAR reduction scheme must be applied at the transmitter. Recently, generalizations of two popular PAR reduction techniques, partial transmit sequences (PTS) and selected mapping (SLM), to multi-antenna systems have been proposed. In this paper, a comparison of these two schemes is accomplished. For that purpose, a point-to-point and a broadcast scenario is assessed. It is shown that under the condition of (almost) same computational complexity, PTS offers significant gains compared to SLM.","PeriodicalId":255495,"journal":{"name":"2008 International ITG Workshop on Smart Antennas","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126581389","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
Receive antenna impact on spatio-temporal availability in satellite-to-indoor broadcasting 接收天线对卫星到室内广播时空有效性的影响
2008 International ITG Workshop on Smart Antennas Pub Date : 2008-03-21 DOI: 10.1109/WSA.2008.4475536
M. Milojević, G. D. Galdo, Nuan Song, M. Haardt, A. Heuberger
{"title":"Receive antenna impact on spatio-temporal availability in satellite-to-indoor broadcasting","authors":"M. Milojević, G. D. Galdo, Nuan Song, M. Haardt, A. Heuberger","doi":"10.1109/WSA.2008.4475536","DOIUrl":"https://doi.org/10.1109/WSA.2008.4475536","url":null,"abstract":"This contribution studies spatio-temporal availability in satellite-to-indoor broadcasting. The performance of both theoretical and measured single and multiple antenna receivers with various polarimetric radiation patterns is compared for different satellite elevation angles. The spatio-temporal satellite to indoor channels are obtained via a 3D ray tracing engine and a geometry-based channel modeling tool. Moreover, the influence of coupling effects between closely spaced antennas on the availability is studied. Under the assumption of a line-of-sight (LOS) connection between the satellite and the wall where the possible window is placed, the indoor performance with and without windows is compared. The results show quantitatively that additional antennas placed at the receiver reduce both the spatial and the temporal variability of the received power, significantly reducing the transmit power required for the same target availability. The antenna coupling effects increase the required link margin.","PeriodicalId":255495,"journal":{"name":"2008 International ITG Workshop on Smart Antennas","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127343210","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
Performance comparison of two sets of constraints in multi-path environment 多路径环境下两组约束的性能比较
2008 International ITG Workshop on Smart Antennas Pub Date : 2008-03-21 DOI: 10.1109/WSA.2008.4475584
Lei Yu, W. Liu, R. Langley
{"title":"Performance comparison of two sets of constraints in multi-path environment","authors":"Lei Yu, W. Liu, R. Langley","doi":"10.1109/WSA.2008.4475584","DOIUrl":"https://doi.org/10.1109/WSA.2008.4475584","url":null,"abstract":"The performance of two sets of constraints for a robust adaptive beamformer in the multi-path environment is studied. By constraining the magnitude or real component of the array responses of the coherent signals to be greater than unity, the desired signal cancellation is avoided. It is shown that although in the single-path environment the two methods have almost the same performance, for the multi-path case, the method imposing extra constraint on the imaginary part of the array response has a better performance.","PeriodicalId":255495,"journal":{"name":"2008 International ITG Workshop on Smart Antennas","volume":"169 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114921466","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
Precoding and spreading for coded MIMO-OFDM 编码MIMO-OFDM的预编码与扩频
2008 International ITG Workshop on Smart Antennas Pub Date : 2008-03-21 DOI: 10.1109/WSA.2008.4475573
D. Yacoub, Benjamin Baumgartner, W. Teich, J. Lindner
{"title":"Precoding and spreading for coded MIMO-OFDM","authors":"D. Yacoub, Benjamin Baumgartner, W. Teich, J. Lindner","doi":"10.1109/WSA.2008.4475573","DOIUrl":"https://doi.org/10.1109/WSA.2008.4475573","url":null,"abstract":"In this paper, precoding in combination with spreading for coded transmission using MIMO-OFDM is investigated. Although MIMO-OFDM systems provide both spatial and frequency diversities that can be exploited by the transmitter, e. g. through spreading, they often suffer from the presence of antenna correlations which can degrade the system performance. Full channel knowledge is usually assumed at the receiver and none at the transmitter. In this paper, partial channel knowledge (transmit correlations) is assumed to be available at the transmitter and is exploited by the precoder. Spreading is also applied at the transmitter to extract the MIMO-OFDM diversity either fully or partially. In addition, coded transmission using convolutional codes is assumed. At the receiver, iterative equalization and decoding is employed assuming full channel knowledge. Two sub-optimum equalizers, soft Cholesky equalizer (SCE) and recurrent neural network equalizer (RNN), are used for equalization. Through the used of EXIT-charts, the performance of the MIMO-OFDM system with both precoding and spreading is analyzed.","PeriodicalId":255495,"journal":{"name":"2008 International ITG Workshop on Smart Antennas","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130716907","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
Iterative EM channel estimation for turbo-coded DS-CDMA receiver under time-varying interference 时变干扰下涡轮编码DS-CDMA接收机的迭代EM信道估计
2008 International ITG Workshop on Smart Antennas Pub Date : 2008-03-21 DOI: 10.1109/WSA.2008.4475555
D. Torrieri, Neelu Bijukchhe, A. Mukherjee, H. Kwon
{"title":"Iterative EM channel estimation for turbo-coded DS-CDMA receiver under time-varying interference","authors":"D. Torrieri, Neelu Bijukchhe, A. Mukherjee, H. Kwon","doi":"10.1109/WSA.2008.4475555","DOIUrl":"https://doi.org/10.1109/WSA.2008.4475555","url":null,"abstract":"This paper proposes a scheme of iteratively obtaining an estimate of channel coefficients and noise power spectral density (PSD) using expectation maximization (EM) for turbo-coded code-division multiple access receivers. The EM channel estimation is tested under two scenarios - time-varying interference environment with pilot symbol-aided modulation, and a single-user environment without any pilot symbols. For the time-varying interference scenario, the initial estimate of channel coefficient and the noise PSD are obtained from pilots and further estimations are refined using turbo decoder soft outputs. In contrast, pilot symbols are eliminated for the single-user iterative receiver with initial estimation performed from the received code symbols, followed by the iterative updates using the feedback from the turbo decoder as before. The refined channel coefficients and noise PSD are iteratively passed to the turbo decoder resulting in improved decoding results for both time-varying interference and single-user scenarios.","PeriodicalId":255495,"journal":{"name":"2008 International ITG Workshop on Smart Antennas","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131228334","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
Off-broadside main beam design for frequency invariant beamformers 频率不变波束形成器的非宽边主波束设计
2008 International ITG Workshop on Smart Antennas Pub Date : 2008-03-21 DOI: 10.1109/WSA.2008.4475558
W. Liu, S. Weiss
{"title":"Off-broadside main beam design for frequency invariant beamformers","authors":"W. Liu, S. Weiss","doi":"10.1109/WSA.2008.4475558","DOIUrl":"https://doi.org/10.1109/WSA.2008.4475558","url":null,"abstract":"In a previously proposed design method for frequency invariant beamforming, the design for the case of an off-broadside main beam is not satisfactory. After a detailed analysis, we propose two methods to overcome this problem: one is to increase the length of the FIR filter attached to each sensor, as a result, we need to sample the transformed desired response more densely in the associated direction; the other one is to design a broadside main beam first, then it is convolved with appropriate steering delay filters. Design examples show that the two methods can provide satisfactory results.","PeriodicalId":255495,"journal":{"name":"2008 International ITG Workshop on Smart Antennas","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131730979","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
Coded performance for combined spatial multiplexing/space-time block coding wireless systems 空间复用/空时分组编码组合无线系统的编码性能
2008 International ITG Workshop on Smart Antennas Pub Date : 2008-03-21 DOI: 10.1109/WSA.2008.4475578
G. Femenias, F. Riera-Palou
{"title":"Coded performance for combined spatial multiplexing/space-time block coding wireless systems","authors":"G. Femenias, F. Riera-Palou","doi":"10.1109/WSA.2008.4475578","DOIUrl":"https://doi.org/10.1109/WSA.2008.4475578","url":null,"abstract":"This paper presents novel detection strategies for hybrid systems combining spatial division multiplexing (SDM) and space- time block coding (STBC). Group-based approaches in which STBC streams are individually targeted as well as direct approaches where the STBC structure is not taken into account in the detection process are considered. We introduce two types of group-based detectors and compare their performance with that of previous group-based and direct proposals in both, coded and uncoded setups, showing the superiority of one of our proposals (linear). Despite the generality of the proposed receivers, the presented simulations results focus on the IEEE 802.1 In wireless local area network (WLAN) as this is one of the first commercial standards to explicitly support hybrid SDM/STBC systems.","PeriodicalId":255495,"journal":{"name":"2008 International ITG Workshop on Smart Antennas","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123907779","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
Multiuser OFDMA optimization: Algorithms and duality gap analysis 多用户OFDMA优化:算法和对偶差距分析
2008 International ITG Workshop on Smart Antennas Pub Date : 2008-03-21 DOI: 10.1109/WSA.2008.4475564
G. Wunder, T. Michel
{"title":"Multiuser OFDMA optimization: Algorithms and duality gap analysis","authors":"G. Wunder, T. Michel","doi":"10.1109/WSA.2008.4475564","DOIUrl":"https://doi.org/10.1109/WSA.2008.4475564","url":null,"abstract":"In this paper we address the problem of power allocation in OFDM multi-user systems, if each subcarrier has to be allocated exclusively to a single user. Such transmit strategies are of particular interest for practical systems because users are orthogonalized and thus signal processing is extremely simple. Due to the combinatorial structure the considered problems are non-convex. We propose algorithms based on the Lagrangian dual avoiding a combinatorial optimization. The resulting power allocations are surprisingly close to the information-theoretic optimum. Moreover, the performance loss can be upper bounded by an expression based on the the Lagrangian duality gap, which yields a valuable statement about any arbitrary resource allocation fulfilling the constraints.","PeriodicalId":255495,"journal":{"name":"2008 International ITG Workshop on Smart Antennas","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128464476","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
Spatial optimization for maximum throughput in multibeam opportunistic schemes 多波束机会方案中最大吞吐量的空间优化
2008 International ITG Workshop on Smart Antennas Pub Date : 2008-03-21 DOI: 10.1109/WSA.2008.4475533
N. Zorba, A. Pérez-Neira
{"title":"Spatial optimization for maximum throughput in multibeam opportunistic schemes","authors":"N. Zorba, A. Pérez-Neira","doi":"10.1109/WSA.2008.4475533","DOIUrl":"https://doi.org/10.1109/WSA.2008.4475533","url":null,"abstract":"Scheduling in a downlink channel based on partial channel state information at the transmitter (CSIT) is carried out through a multibeam opportunistic beamforming technique. A practical transmission strategy is presented where a minimum rate per user is required within a given time interval, to satisfy maximum delay restrictions for the user's application. The proposed strategy achieves these quality of service (QoS) restrictions at the same time as an opportunistic user selection is performed, so that the system multiuser gain is extracted while the QoS is satisfied. The system minimum-guaranteed throughput is then formulated in a closed form expression, and a throughput maximization is performed through the optimization of the number of transmitting beams, therefore exploiting the system spatial capabilities in the most convenient approach.","PeriodicalId":255495,"journal":{"name":"2008 International ITG Workshop on Smart Antennas","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116817923","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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