Pub Date : 2001-03-20DOI: 10.1109/SPAWC.2001.923875
BuiLong Thanh, V. Krishnamurthy, R. Evans
This paper develops a sequential composite hypotheses test for detecting failure of a decision directed recursive least squares (RLS) multiuser detector (MUD) and convergence of a blind RLS MUD when used in the downlink of a DS-CDMA system. Simulations demonstrate the effectiveness of the test and characterize the SIR improvement achievable in a dynamic environment.
{"title":"Detection aided recursive least squares multiuser detection in the downlink of DS/CDMA mobile systems","authors":"BuiLong Thanh, V. Krishnamurthy, R. Evans","doi":"10.1109/SPAWC.2001.923875","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923875","url":null,"abstract":"This paper develops a sequential composite hypotheses test for detecting failure of a decision directed recursive least squares (RLS) multiuser detector (MUD) and convergence of a blind RLS MUD when used in the downlink of a DS-CDMA system. Simulations demonstrate the effectiveness of the test and characterize the SIR improvement achievable in a dynamic environment.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130724509","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}
Pub Date : 2001-03-20DOI: 10.1109/SPAWC.2001.923893
Chong-Yung Chi, Ching-Yung Chen
Ding and Nguyen's (2000) kurtosis maximization algorithm (KMA) for blind signal separation and antenna beamforming assumes the absence of multipath channels. This paper proposes a multistage source separation (MSS) algorithm assuming that source signals are independent identically distributed (iid) non-Gaussian and received in the presence of multiple paths (as practically happens in wireless communications). The proposed MSS algorithm includes extraction and blind maximum ratio combing (BMRC) of a source signal from different paths using a fast KMA (FKMA), besides signal classification, time delay estimation, and cancellation of the contribution of the extracted source signal from the received signal at each stage. The proposed MSS algorithm with no need of prior information about the array configuration and direction of arrival (DOA) is supported through computer simulation.
{"title":"Blind beamforming and maximum ratio combining by kurtosis maximization for source separation in multipath","authors":"Chong-Yung Chi, Ching-Yung Chen","doi":"10.1109/SPAWC.2001.923893","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923893","url":null,"abstract":"Ding and Nguyen's (2000) kurtosis maximization algorithm (KMA) for blind signal separation and antenna beamforming assumes the absence of multipath channels. This paper proposes a multistage source separation (MSS) algorithm assuming that source signals are independent identically distributed (iid) non-Gaussian and received in the presence of multiple paths (as practically happens in wireless communications). The proposed MSS algorithm includes extraction and blind maximum ratio combing (BMRC) of a source signal from different paths using a fast KMA (FKMA), besides signal classification, time delay estimation, and cancellation of the contribution of the extracted source signal from the received signal at each stage. The proposed MSS algorithm with no need of prior information about the array configuration and direction of arrival (DOA) is supported through computer simulation.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131195331","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}
Pub Date : 2001-03-20DOI: 10.1109/SPAWC.2001.923859
Chong-Yung Chi, Chii-Horng Chen
Tugnait's multi-input multi-output inverse filter criteria (MIMO-IFC) using either second- and third-order or second- and fourth-order cumulants for blind deconvolution are extended to those using second- and higher-order (/spl ges/ 3) cumulants. Next, a blind maximum ratio combining (BMRC) method using the MIMO-IFC is proposed. Then a blind equalization algorithm for multiuser DS/CDMA systems in multipath channels is proposed using the proposed BMRC method and MIMO-IFC. Finally, some simulation results are provided to support the proposed algorithm.
{"title":"MIMO inverse filter criteria and blind maximum ratio combining using HOS for equalization of DS/CDMA systems in multipath","authors":"Chong-Yung Chi, Chii-Horng Chen","doi":"10.1109/SPAWC.2001.923859","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923859","url":null,"abstract":"Tugnait's multi-input multi-output inverse filter criteria (MIMO-IFC) using either second- and third-order or second- and fourth-order cumulants for blind deconvolution are extended to those using second- and higher-order (/spl ges/ 3) cumulants. Next, a blind maximum ratio combining (BMRC) method using the MIMO-IFC is proposed. Then a blind equalization algorithm for multiuser DS/CDMA systems in multipath channels is proposed using the proposed BMRC method and MIMO-IFC. Finally, some simulation results are provided to support the proposed algorithm.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"113 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133850307","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}
In order to overcome the MAI and ISI problems in time-varying multipath fading channels, a novel H/sub /spl infin//-subweight algorithm for the decision feedback equalizer (DFE) in a DS-CDMA system is presented. The subweight technique can reduce the computational load of the H/sub /spl infin// algorithm, but dynamic estimation error in subweight partition may degrade performance. The advantage of insensitivity to modeling error of the H/sub /spl infin// algorithm just can mitigate the degradation of the subweight technique. Therefore, the individual advantages of the H/sub /spl infin// algorithm and subweight technique can be successfully integrated. The H/sub /spl infin//-subweight algorithm owns the advantages of low complexity and robustness against modeling error caused by the time-varying multipath channels as well as subweight partition. On the other hand, the RLS-subweight algorithm seriously suffers from the drawback of dynamic estimation error. The reduction of computational complexity by subweight partition is analyzed. Simulation results show that the H/sub /spl infin//-subweight DPE outperforms the RLS-subweight DFE in suppressing equalization error.
{"title":"Adaptive H/sub /spl infin//-subweight equalizer for DS-CDMA communication system in time-varying multipath channels","authors":"Ching-Tai Chiang, Chian-Chung Chen, Yuan-Hwang Chen","doi":"10.1109/SPAWC.2001.923858","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923858","url":null,"abstract":"In order to overcome the MAI and ISI problems in time-varying multipath fading channels, a novel H/sub /spl infin//-subweight algorithm for the decision feedback equalizer (DFE) in a DS-CDMA system is presented. The subweight technique can reduce the computational load of the H/sub /spl infin// algorithm, but dynamic estimation error in subweight partition may degrade performance. The advantage of insensitivity to modeling error of the H/sub /spl infin// algorithm just can mitigate the degradation of the subweight technique. Therefore, the individual advantages of the H/sub /spl infin// algorithm and subweight technique can be successfully integrated. The H/sub /spl infin//-subweight algorithm owns the advantages of low complexity and robustness against modeling error caused by the time-varying multipath channels as well as subweight partition. On the other hand, the RLS-subweight algorithm seriously suffers from the drawback of dynamic estimation error. The reduction of computational complexity by subweight partition is analyzed. Simulation results show that the H/sub /spl infin//-subweight DPE outperforms the RLS-subweight DFE in suppressing equalization error.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"178 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128165653","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}
Pub Date : 2001-03-20DOI: 10.1109/SPAWC.2001.923923
Hsien-Tsai Wu, Jui-Yuan Chang, Chun-Bo Tseng, Chia-Hao Kao, W. Hung
This project comes from the inconvenience of the traditional message-board for a visitor when the host is not at home. Besides the written message, a visitor can also leave a voice message, can telephone his host immediately, and also include a simple security checking in our board system. When the visitor pushes a special key, the telephone system autodials the preset telephone number by the host. To reduce the system cost, the compressed voice message is stored in the internal and external memory space of the DSP chip instead of the voice IC.
{"title":"Active DSP message-board","authors":"Hsien-Tsai Wu, Jui-Yuan Chang, Chun-Bo Tseng, Chia-Hao Kao, W. Hung","doi":"10.1109/SPAWC.2001.923923","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923923","url":null,"abstract":"This project comes from the inconvenience of the traditional message-board for a visitor when the host is not at home. Besides the written message, a visitor can also leave a voice message, can telephone his host immediately, and also include a simple security checking in our board system. When the visitor pushes a special key, the telephone system autodials the preset telephone number by the host. To reduce the system cost, the compressed voice message is stored in the internal and external memory space of the DSP chip instead of the voice IC.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130661260","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}
Pub Date : 2001-03-20DOI: 10.1109/SPAWC.2001.923922
J. Manton, Y. Hua
The problem of approximating a matrix by one of lower rank occurs in a number of signal processing problems, including reduced rank Wiener filtering and reduced rank maximum likelihood estimation. This paper derives a novel algorithm for computing the optimal rank-reduced approximation of a given matrix under an arbitrary weighted norm. Simulations demonstrate the advantages of the algorithm over the traditional alternating projections algorithm.
{"title":"A novel algorithm for computing rank reduced matrix approximations","authors":"J. Manton, Y. Hua","doi":"10.1109/SPAWC.2001.923922","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923922","url":null,"abstract":"The problem of approximating a matrix by one of lower rank occurs in a number of signal processing problems, including reduced rank Wiener filtering and reduced rank maximum likelihood estimation. This paper derives a novel algorithm for computing the optimal rank-reduced approximation of a given matrix under an arbitrary weighted norm. Simulations demonstrate the advantages of the algorithm over the traditional alternating projections algorithm.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128990701","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}
Pub Date : 2001-03-20DOI: 10.1109/SPAWC.2001.923895
Yimin D. Zhang, M. Amin, A. Lindsey, K. Yang
Space-time coding and interference cancellation based on orthogonal projection are powerful techniques to improve the communication quality and capacity in downlink CDMA systems. The space-time encoder output stream is transmitted through the fading channel using multiple transmitter antennas, increasing communication reliability against multipath fading. On the other hand, orthogonal projection-based interference cancellation mitigates the multiuser interference. This is achieved by projecting the received signals to the orthogonal subspace of the interference signal subspace. We propose a method that combines these two techniques. The proposed method allows the downlink CDMA system to be robust against both channel fading and multiuser access interference. Simulation results are provided for both static and dynamic fading channel environments.
{"title":"Downlink CDMA systems with space-time codes and interference cancellation","authors":"Yimin D. Zhang, M. Amin, A. Lindsey, K. Yang","doi":"10.1109/SPAWC.2001.923895","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923895","url":null,"abstract":"Space-time coding and interference cancellation based on orthogonal projection are powerful techniques to improve the communication quality and capacity in downlink CDMA systems. The space-time encoder output stream is transmitted through the fading channel using multiple transmitter antennas, increasing communication reliability against multipath fading. On the other hand, orthogonal projection-based interference cancellation mitigates the multiuser interference. This is achieved by projecting the received signals to the orthogonal subspace of the interference signal subspace. We propose a method that combines these two techniques. The proposed method allows the downlink CDMA system to be robust against both channel fading and multiuser access interference. Simulation results are provided for both static and dynamic fading channel environments.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122501863","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}
Pub Date : 2001-03-20DOI: 10.1109/SPAWC.2001.923864
P. Nanan, M. Nakagawa
This paper studies the performance of the uplink synchronous multi-carrier code division multiple access. The synchronization in uplink transmission can be maintained by using signaling to control it. The performance is evaluated compared with the asynchronous system. Numerical results show that our synchronous transmission technique can offer better performance than conventional asynchronous transmission, especially for an exponentially decaying multipath intensity profile.
{"title":"Performance of uplink synchronous multi-carrier CDMA in wireless communications","authors":"P. Nanan, M. Nakagawa","doi":"10.1109/SPAWC.2001.923864","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923864","url":null,"abstract":"This paper studies the performance of the uplink synchronous multi-carrier code division multiple access. The synchronization in uplink transmission can be maintained by using signaling to control it. The performance is evaluated compared with the asynchronous system. Numerical results show that our synchronous transmission technique can offer better performance than conventional asynchronous transmission, especially for an exponentially decaying multipath intensity profile.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127703269","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}
Pub Date : 2001-03-20DOI: 10.1109/SPAWC.2001.923912
B. Banister, J. Zeidler
It is generally accepted that the downlink of next generation cellular systems will require greater capacity than the uplink, due to the asymmetry of data traffic patterns. The use of transmit adaptive antenna arrays at the base station is a promising area for downlink capacity improvement. This paper describes a gradient algorithm utilizing mobile to base feedback in order to achieve some of those possible gains. A simple algorithm for adaptation of the complex baseband weights of a transmit antenna array utilizing feedback from the receiving unit is presented. A dedicated pilot signal is transmitted from the transmitting unit with a pair of perturbed test weights; a feedback bit is transmitted from the receiving unit indicating which weight vector provided the larger power; the transmitting unit adjusts a base weight to this selection and continues the process. This approach is shown to be a coarse stochastic gradient algorithm. The settling time and steady state characteristics of the algorithm are investigated analytically and verified by simulation, and the algorithm is shown to converge to those weights which maximize the power delivered to the receiver.
{"title":"A stochastic gradient algorithm for transmit antenna weight adaptation with feedback","authors":"B. Banister, J. Zeidler","doi":"10.1109/SPAWC.2001.923912","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923912","url":null,"abstract":"It is generally accepted that the downlink of next generation cellular systems will require greater capacity than the uplink, due to the asymmetry of data traffic patterns. The use of transmit adaptive antenna arrays at the base station is a promising area for downlink capacity improvement. This paper describes a gradient algorithm utilizing mobile to base feedback in order to achieve some of those possible gains. A simple algorithm for adaptation of the complex baseband weights of a transmit antenna array utilizing feedback from the receiving unit is presented. A dedicated pilot signal is transmitted from the transmitting unit with a pair of perturbed test weights; a feedback bit is transmitted from the receiving unit indicating which weight vector provided the larger power; the transmitting unit adjusts a base weight to this selection and continues the process. This approach is shown to be a coarse stochastic gradient algorithm. The settling time and steady state characteristics of the algorithm are investigated analytically and verified by simulation, and the algorithm is shown to converge to those weights which maximize the power delivered to the receiver.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127145944","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}
Pub Date : 2001-03-20DOI: 10.1109/SPAWC.2001.923871
W. Sheen, M. Chang, Cheng-Shong Wu
The non-coherent second-order digital delay locked loop with Doppler shift present is analyzed. The analysis is unique on two counts. First, the effects of the loop A/D quantization on the loop performance, which have been neglected previously, are examined. Second, MTLL (mean time to lose lock) and MSE (mean square error) are evaluated more accurately than by previous methods. Numerical results show that: (1) the number of quantization levels significantly alters the loop behavior, including the lock-in range, transient responses, MTLL and MSE; and (2) the traditional analysis based on Gaussian approximation may result in a large error in performance evaluation when the A/D quantization is taken into account.
{"title":"Performance analysis of digital second order delay locked loops for direct sequence spread spectrum systems with Doppler shift and A/D quantization","authors":"W. Sheen, M. Chang, Cheng-Shong Wu","doi":"10.1109/SPAWC.2001.923871","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923871","url":null,"abstract":"The non-coherent second-order digital delay locked loop with Doppler shift present is analyzed. The analysis is unique on two counts. First, the effects of the loop A/D quantization on the loop performance, which have been neglected previously, are examined. Second, MTLL (mean time to lose lock) and MSE (mean square error) are evaluated more accurately than by previous methods. Numerical results show that: (1) the number of quantization levels significantly alters the loop behavior, including the lock-in range, transient responses, MTLL and MSE; and (2) the traditional analysis based on Gaussian approximation may result in a large error in performance evaluation when the A/D quantization is taken into account.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"137 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116025324","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：