Pub Date : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371799
X. Tran, T. Taniguchi, Y. Karasawa
We propose a reception scheme with adaptive beamforming for multiuser Alamouti-type space-time block code. The proposed scheme performs space-time processing to optimally estimate the transmitted space-time block coded symbols based on the minimum mean square error (MMSE) criterion. Simulation results show that the scheme achieves good performance in a multiuser system. With N receive antennas the scheme can support N users each with two antennas.
{"title":"Adaptive beamforming for multiuser space-time block coded systems","authors":"X. Tran, T. Taniguchi, Y. Karasawa","doi":"10.1109/ISSSTA.2004.1371799","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371799","url":null,"abstract":"We propose a reception scheme with adaptive beamforming for multiuser Alamouti-type space-time block code. The proposed scheme performs space-time processing to optimally estimate the transmitted space-time block coded symbols based on the minimum mean square error (MMSE) criterion. Simulation results show that the scheme achieves good performance in a multiuser system. With N receive antennas the scheme can support N users each with two antennas.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133439881","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 : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371732
Xia Wang, Shihua Zhu, Delong Sun
For orthogonal frequency-division multiplexing (OFDM) communication systems, the frequency offsets in mobile radio channels distort the orthogonality between subcarriers, resulting in inter-carrier interference (ICI), which seriously degrades the performance of systems. Based on ICI coefficients analysis and reasonable estimation of the frequency offset, the paper presents a novel decorrelation interference cancellation method with the use of frequency-domain equalization at the receiver. Without the iterative operation on the weighting coefficients and the inverse operation on the matrix, ICI can be eliminated by directly using the cyclic embedding algorithm of the Toeplitz matrix in terms of the discrete Fourier transform (DFT). Compared with conventional frequency-domain equalization, this new scheme has better convergence reliability and lower computational complexity. Simulation results show that an OFDM system using the proposed ICI cancellation scheme can effectively eliminate ICI, have significant performance improvement and mitigate the effects of OFDM communication systems. The scheme works very well in the multipath radio channel and high-speed mobile environment.
{"title":"Inter-carrier interference cancellation method based on cyclic embedding for OFDM communication systems","authors":"Xia Wang, Shihua Zhu, Delong Sun","doi":"10.1109/ISSSTA.2004.1371732","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371732","url":null,"abstract":"For orthogonal frequency-division multiplexing (OFDM) communication systems, the frequency offsets in mobile radio channels distort the orthogonality between subcarriers, resulting in inter-carrier interference (ICI), which seriously degrades the performance of systems. Based on ICI coefficients analysis and reasonable estimation of the frequency offset, the paper presents a novel decorrelation interference cancellation method with the use of frequency-domain equalization at the receiver. Without the iterative operation on the weighting coefficients and the inverse operation on the matrix, ICI can be eliminated by directly using the cyclic embedding algorithm of the Toeplitz matrix in terms of the discrete Fourier transform (DFT). Compared with conventional frequency-domain equalization, this new scheme has better convergence reliability and lower computational complexity. Simulation results show that an OFDM system using the proposed ICI cancellation scheme can effectively eliminate ICI, have significant performance improvement and mitigate the effects of OFDM communication systems. The scheme works very well in the multipath radio channel and high-speed mobile environment.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133469018","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 : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371708
Tao Wang
The multi-access performance of the single-user correlation receiver of time hopping impulse radio with bipolar modulation is analyzed in terms of the signal-to-noise ratio and the bit error rate from the spectrum point of view. The closed form expressions for the signal power spectral density, the SNR and the BER are derived, based on which the signal parameter design guides are presented in a straightforward manner to improve the multi-access performance. Simulations demonstrate the theoretical analysis, and show the influence of signal parameters on the multi-access performance.
{"title":"Multi-access performance analysis of TH-BPM impulse radio from spectrum point of view","authors":"Tao Wang","doi":"10.1109/ISSSTA.2004.1371708","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371708","url":null,"abstract":"The multi-access performance of the single-user correlation receiver of time hopping impulse radio with bipolar modulation is analyzed in terms of the signal-to-noise ratio and the bit error rate from the spectrum point of view. The closed form expressions for the signal power spectral density, the SNR and the BER are derived, based on which the signal parameter design guides are presented in a straightforward manner to improve the multi-access performance. Simulations demonstrate the theoretical analysis, and show the influence of signal parameters on the multi-access performance.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131994441","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 : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371772
J.C. Silva, N. Souto, A. Correia, F. Cercas, A. Rodrigues
This paper addresses the problem of the UMTS downlink multipath interference and its impact on the performance of the high speed data packet access (HSDPA). The performance is studied for specific channel quality indicator (CQI) values defined in 3GPP, using both QPSK and 16-QAM modulations. It is shown that the multipath interference introduced by the channel induces a severe performance loss, which is especially relevant for the CQI with 16-QAM modulation, with a high number of concurrent physical channels. A multipath interference canceller (MPIC) using clipped soft decision (CSD) is proposed for suppressing this interference. Results with and without MPIC are presented, showing that a considerable performance gain can be obtained with the use of the MPIC.
{"title":"Multipath interference canceller for high speed downlink packet access in enhanced UMTS networks","authors":"J.C. Silva, N. Souto, A. Correia, F. Cercas, A. Rodrigues","doi":"10.1109/ISSSTA.2004.1371772","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371772","url":null,"abstract":"This paper addresses the problem of the UMTS downlink multipath interference and its impact on the performance of the high speed data packet access (HSDPA). The performance is studied for specific channel quality indicator (CQI) values defined in 3GPP, using both QPSK and 16-QAM modulations. It is shown that the multipath interference introduced by the channel induces a severe performance loss, which is especially relevant for the CQI with 16-QAM modulation, with a high number of concurrent physical channels. A multipath interference canceller (MPIC) using clipped soft decision (CSD) is proposed for suppressing this interference. Results with and without MPIC are presented, showing that a considerable performance gain can be obtained with the use of the MPIC.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"130 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133147985","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 : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371741
Jingyu Hua, X. You, Dongming Wang, Qing-min Meng, Y. Kim
The classical channel estimator is a linear interpolator based on PSAM (pilot symbol assisted modulation). The interpolation length can be determined by the estimated Doppler shift because the channel variation rate is related to its maximum Doppler shift, which leads to an adaptive WMSA (weighted multislot average) channel estimation method to improve channel estimation accuracy. Simulation results show good performance in a wide range of velocities.
{"title":"Adaptive WMSA channel estimation based on Doppler shift estimation in CP-SCBT systems","authors":"Jingyu Hua, X. You, Dongming Wang, Qing-min Meng, Y. Kim","doi":"10.1109/ISSSTA.2004.1371741","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371741","url":null,"abstract":"The classical channel estimator is a linear interpolator based on PSAM (pilot symbol assisted modulation). The interpolation length can be determined by the estimated Doppler shift because the channel variation rate is related to its maximum Doppler shift, which leads to an adaptive WMSA (weighted multislot average) channel estimation method to improve channel estimation accuracy. Simulation results show good performance in a wide range of velocities.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"133 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124276233","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 : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371828
Heng-Siong Lim, B. Venkatesh
This work presents a new two-phase, memetic algorithm to solve the maximum-likelihood multiuser detection problem. The algorithm uses a standard evolutionary programming (EP) for the base level search, which makes a quick decision to direct the search towards the optimal region (phase-1). The local optimization by k-opt heuristic local search is then employed to do fine tuning (phase-2). In order to validate the effectiveness of the proposed method, the algorithm is applied to 10- and 20-user synchronous direct-sequence code-division multiple-access (DS-CDMA) systems. The results clearly show that the algorithm not only improves the solution quality but also makes the EP more efficient in terms of number of iterations to reach the global optimum.
{"title":"An effective memetic algorithm for the optimum multiuser detection problem","authors":"Heng-Siong Lim, B. Venkatesh","doi":"10.1109/ISSSTA.2004.1371828","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371828","url":null,"abstract":"This work presents a new two-phase, memetic algorithm to solve the maximum-likelihood multiuser detection problem. The algorithm uses a standard evolutionary programming (EP) for the base level search, which makes a quick decision to direct the search towards the optimal region (phase-1). The local optimization by k-opt heuristic local search is then employed to do fine tuning (phase-2). In order to validate the effectiveness of the proposed method, the algorithm is applied to 10- and 20-user synchronous direct-sequence code-division multiple-access (DS-CDMA) systems. The results clearly show that the algorithm not only improves the solution quality but also makes the EP more efficient in terms of number of iterations to reach the global optimum.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125205048","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 : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371805
B. Mouhouche, Karim Abed-Meraim, S. Burykh
We propose a new blind interference scheme algorithm suitable for the direct-sequence code-division multiple access (DS/CDMA) downlink. The interferer codes are unknown but the family to which they belong is supposed to be known. The proposed technique is blind in the sense that only the desired user's spreading code is assumed to be known a priori. The remaining parameters required for the interference cancellation such as spreading codes and energies of interfering users are estimated using subspace decomposition and projection on the family of codes. Fast and efficient implementations are discussed. Therefore, unlike standard interference cancellers which can be used only in the uplink, the proposed method can be implemented at the mobile terminal.
{"title":"Spreading code detection and blind interference cancellation for DS/CDMA downlink","authors":"B. Mouhouche, Karim Abed-Meraim, S. Burykh","doi":"10.1109/ISSSTA.2004.1371805","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371805","url":null,"abstract":"We propose a new blind interference scheme algorithm suitable for the direct-sequence code-division multiple access (DS/CDMA) downlink. The interferer codes are unknown but the family to which they belong is supposed to be known. The proposed technique is blind in the sense that only the desired user's spreading code is assumed to be known a priori. The remaining parameters required for the interference cancellation such as spreading codes and energies of interfering users are estimated using subspace decomposition and projection on the family of codes. Fast and efficient implementations are discussed. Therefore, unlike standard interference cancellers which can be used only in the uplink, the proposed method can be implemented at the mobile terminal.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134196499","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 : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371657
Luis Renato Lage Goncalves, A. Gameiro
Direct sequence code division multiple access (DS-CDMA) signals exhibit cyclostationary properties which imply a redundancy between frequency components separated by multiples of the symbol rate. In this paper a multiple access interference canceller (frequency shift canceller) that explores this property is presented. This linear frequency domain canceller operates on the spread signal in such way that the interference and noise at its output is minimized (minimum mean squared error criterion). The frequency shift canceller (FSC) performance was evaluated for a UMTS-TDD scenario and multi-sensor configurations, where the cases of diversity and beamforming were considered. All these configurations are evaluated concatenated with a parallel interference canceller (PIC-2D). The results are benchmarked against the performance of the conventional RAKE-2D detector, the conventional PIC-2D detector and single user scenario, and we observe considerable performance gains with the FSC especially for the diversity case and a performance close to the single user case when it was evaluated jointly with PIC-2D.
{"title":"Multi-sensor frequency domain multiple access interference canceller for DS-CDMA systems","authors":"Luis Renato Lage Goncalves, A. Gameiro","doi":"10.1109/ISSSTA.2004.1371657","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371657","url":null,"abstract":"Direct sequence code division multiple access (DS-CDMA) signals exhibit cyclostationary properties which imply a redundancy between frequency components separated by multiples of the symbol rate. In this paper a multiple access interference canceller (frequency shift canceller) that explores this property is presented. This linear frequency domain canceller operates on the spread signal in such way that the interference and noise at its output is minimized (minimum mean squared error criterion). The frequency shift canceller (FSC) performance was evaluated for a UMTS-TDD scenario and multi-sensor configurations, where the cases of diversity and beamforming were considered. All these configurations are evaluated concatenated with a parallel interference canceller (PIC-2D). The results are benchmarked against the performance of the conventional RAKE-2D detector, the conventional PIC-2D detector and single user scenario, and we observe considerable performance gains with the FSC especially for the diversity case and a performance close to the single user case when it was evaluated jointly with PIC-2D.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116282635","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 : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371758
V. Trajkovic, P. Rapajic
The analysis of adaptive decision feedback turbo equalization is provided. The turbo detector is a reduced-complexity adaptive turbo equalizer where trellis-based channel equalization is replaced by the adaptive decision feedback equalizer (DFE). We show that for severe intersymbol interference (ISI) the turbo effect (waterfall region) starts at lower SNR relative to the detector applying conventional MMSE DFE coefficients assuming perfect feedback.
{"title":"Adaptive decision feedback turbo equalization and multiuser detection","authors":"V. Trajkovic, P. Rapajic","doi":"10.1109/ISSSTA.2004.1371758","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371758","url":null,"abstract":"The analysis of adaptive decision feedback turbo equalization is provided. The turbo detector is a reduced-complexity adaptive turbo equalizer where trellis-based channel equalization is replaced by the adaptive decision feedback equalizer (DFE). We show that for severe intersymbol interference (ISI) the turbo effect (waterfall region) starts at lower SNR relative to the detector applying conventional MMSE DFE coefficients assuming perfect feedback.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123472352","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 : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371839
Liru Lu, V. Dubey
Spread-time code division multiple access (ST-CDMA) is an alternative CDMA scheme to spread spectrum (SS). The ST-CDMA is proposed for bandlimited multiple access channels, which can be considered the time-frequency dual of SS-CDMA. We propose a new ST-CDMA system based on the orthogonal complete complementary (CC) code. The performance of the proposed system is investigated and the simulation is done to compare with the conventional ST-CDMA system using PN codes. The results show the CC code-based ST-CDMA performs better than the existing system, which can be an additional choice for future multiple access communications systems.
{"title":"Complete complementary code for spread time CDMA system","authors":"Liru Lu, V. Dubey","doi":"10.1109/ISSSTA.2004.1371839","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371839","url":null,"abstract":"Spread-time code division multiple access (ST-CDMA) is an alternative CDMA scheme to spread spectrum (SS). The ST-CDMA is proposed for bandlimited multiple access channels, which can be considered the time-frequency dual of SS-CDMA. We propose a new ST-CDMA system based on the orthogonal complete complementary (CC) code. The performance of the proposed system is investigated and the simulation is done to compare with the conventional ST-CDMA system using PN codes. The results show the CC code-based ST-CDMA performs better than the existing system, which can be an additional choice for future multiple access communications systems.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125390587","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}
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