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.2001.923847
E. Batut
Channel estimation is of crucial importance for tomorrow's wireless mobile communication systems. However, high-performance algorithms often come at the cost of a high computational complexity, which makes them unsuitable for the terminal equipment. A low-complexity version of an iterative channel estimator is proposed for the third-generation WB-CDMA (wideband code division multiple access) terminal. Its performance compares favorably with that of the original version. Furthermore, a novel criterion for false-path detection is introduced, thus avoiding useless computations being performed later on. Possible improvements are proposed.
{"title":"A low complexity channel estimation scheme for the WB-CDMA terminal","authors":"E. Batut","doi":"10.1109/SPAWC.2001.923847","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923847","url":null,"abstract":"Channel estimation is of crucial importance for tomorrow's wireless mobile communication systems. However, high-performance algorithms often come at the cost of a high computational complexity, which makes them unsuitable for the terminal equipment. A low-complexity version of an iterative channel estimator is proposed for the third-generation WB-CDMA (wideband code division multiple access) terminal. Its performance compares favorably with that of the original version. Furthermore, a novel criterion for false-path detection is introduced, thus avoiding useless computations being performed later on. Possible improvements are proposed.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"108 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":"131154264","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.2001.923898
Fu-Chuan Hung, Char-Dir Chung
This paper investigates the trellis-coded schemes based on a newly developed L-phase-leveled coherent frequency/phase modulation (LCFPM) for the additive white Gaussian noise channel. Comparison with conventional joint frequency and phase modulations is given in terms of power and bandwidth efficiencies. It is found that the trellis-coded LCFPM is highly competitive in power and bandwidth efficiencies in comparison to conventional dual-frequency joint frequency and phase modulations.
{"title":"Trellis coding of L-phase-level coherent frequency/phase modulated signals","authors":"Fu-Chuan Hung, Char-Dir Chung","doi":"10.1109/SPAWC.2001.923898","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923898","url":null,"abstract":"This paper investigates the trellis-coded schemes based on a newly developed L-phase-leveled coherent frequency/phase modulation (LCFPM) for the additive white Gaussian noise channel. Comparison with conventional joint frequency and phase modulations is given in terms of power and bandwidth efficiencies. It is found that the trellis-coded LCFPM is highly competitive in power and bandwidth efficiencies in comparison to conventional dual-frequency joint frequency and phase modulations.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"35 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":"124947415","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.2001.923888
H. Chen, C. Ravishankar, Wei Lu
This paper presents a novel scheme for improving signal detection and timing estimation in communication systems that employ unique words (reference symbols) to aid signal acquisition. The newly proposed algorithm which is termed summation likelihood ratio test (SLRT) performs a summation of likelihood values over a suitable search range. Computer simulations of the SLRT and the generalized likelihood ratio test (GLRT) have been performed for a particular classification scenario of the traffic channel (TCH) and the fast associated control channel (FACCH) traditionally used in terrestrial wireless communications systems such as GSM and mobile satellite communication systems. The simulation results demonstrate that the SLRT outperforms the GLRT significantly.
{"title":"Signal detection and timing estimation via summation likelihood ratio test","authors":"H. Chen, C. Ravishankar, Wei Lu","doi":"10.1109/SPAWC.2001.923888","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923888","url":null,"abstract":"This paper presents a novel scheme for improving signal detection and timing estimation in communication systems that employ unique words (reference symbols) to aid signal acquisition. The newly proposed algorithm which is termed summation likelihood ratio test (SLRT) performs a summation of likelihood values over a suitable search range. Computer simulations of the SLRT and the generalized likelihood ratio test (GLRT) have been performed for a particular classification scenario of the traffic channel (TCH) and the fast associated control channel (FACCH) traditionally used in terrestrial wireless communications systems such as GSM and mobile satellite communication systems. The simulation results demonstrate that the SLRT outperforms the GLRT significantly.","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":"114213911","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.2001.923842
S. Affes, H. Hansen, P. Mermelstein
The single-user CDMA spatio-temporal array receiver (STAR-SU) can be extended to a multiuser version (STAR-MU) by incorporating interference subspace rejection (ISR) using spatio-temporal null-beamforming. We can exploit the data-projection step implemented there to enhance the channel identification for STAR-SU so that it is significantly more robust to near-far power variations than the previous formulation. Our approach effectively decomposes the MU subspace tracking into much simpler single-user 1D subspace tracking operations. Simulations on the downlink reveal that the performance of the new STAR-SU is close to the single-user bound even for near-far ratios as high as 18 dB.
{"title":"Near-far resistant single-user channel identification by interference subspace rejection in wideband CDMA","authors":"S. Affes, H. Hansen, P. Mermelstein","doi":"10.1109/SPAWC.2001.923842","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923842","url":null,"abstract":"The single-user CDMA spatio-temporal array receiver (STAR-SU) can be extended to a multiuser version (STAR-MU) by incorporating interference subspace rejection (ISR) using spatio-temporal null-beamforming. We can exploit the data-projection step implemented there to enhance the channel identification for STAR-SU so that it is significantly more robust to near-far power variations than the previous formulation. Our approach effectively decomposes the MU subspace tracking into much simpler single-user 1D subspace tracking operations. Simulations on the downlink reveal that the performance of the new STAR-SU is close to the single-user bound even for near-far ratios as high as 18 dB.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"13 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":"124027410","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.2001.923882
Wen-Sheng Hou, Bor‐Sen Chen
In the presence of narrowband interference (NBI), the performance of direct-sequence code-division multiple access (DS-CDMA) communication systems can be improved by using various interference cancellation schemes. A scheme of parallel interference cancellators (PIC), which includes a set of NBI cancellation filters and a set of multiple access interference (MAI) cancellation filters, is developed to improve the signal-to-interference ratio (SIR) and handle the MAI effect. In order to avoid performance deterioration due to the unreliable initial detection, a robust coefficient /spl gamma/ is introduced in our proposed design criterion.
{"title":"Adaptive narrow-band interference cancellation in DS-CDMA communications","authors":"Wen-Sheng Hou, Bor‐Sen Chen","doi":"10.1109/SPAWC.2001.923882","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923882","url":null,"abstract":"In the presence of narrowband interference (NBI), the performance of direct-sequence code-division multiple access (DS-CDMA) communication systems can be improved by using various interference cancellation schemes. A scheme of parallel interference cancellators (PIC), which includes a set of NBI cancellation filters and a set of multiple access interference (MAI) cancellation filters, is developed to improve the signal-to-interference ratio (SIR) and handle the MAI effect. In order to avoid performance deterioration due to the unreliable initial detection, a robust coefficient /spl gamma/ is introduced in our proposed design criterion.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"2 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":"124312371","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.2001.923908
S. Tomisato, T. Matsumoto
Joint spatial and temporal equalization techniques are considered most effective in reducing the effects of cochannel interference (CCI) and intersymbol interference (ISI) in broadband mobile communications. This paper proposes a new configuration of spatial and temporal equalizer (S/T-equalizer) using separated spatial and temporal signal processing. The S/T-equalizer combines concepts of the adaptive array antenna (AAA) and temporal equalizer (TE). An iterative parameter estimation technique is also proposed for the S/T-equalizer. Computer simulations were conducted to demonstrate the effectiveness of the proposed S/T-equalizer. Results of computer simulations show that the proposed S/T-equalizer can achieve excellent performance in the presence of CCI and ISI.
{"title":"A joint spatial and temporal equalizer using separated spatial and temporal signal processing for broadband mobile radio communications","authors":"S. Tomisato, T. Matsumoto","doi":"10.1109/SPAWC.2001.923908","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923908","url":null,"abstract":"Joint spatial and temporal equalization techniques are considered most effective in reducing the effects of cochannel interference (CCI) and intersymbol interference (ISI) in broadband mobile communications. This paper proposes a new configuration of spatial and temporal equalizer (S/T-equalizer) using separated spatial and temporal signal processing. The S/T-equalizer combines concepts of the adaptive array antenna (AAA) and temporal equalizer (TE). An iterative parameter estimation technique is also proposed for the S/T-equalizer. Computer simulations were conducted to demonstrate the effectiveness of the proposed S/T-equalizer. Results of computer simulations show that the proposed S/T-equalizer can achieve excellent performance in the presence of CCI and ISI.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"44 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":"126345120","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.2001.923933
S. Patnaik, R. Pal
This paper presents an image compression method using auto-associative neural network and embedded zero-tree coding. The role of the neural network (NN) is to decompose the image stage by stage, which enables analysis similar to wavelet decomposition. This works on the principle of principal component extraction (PCE). Network training is achieved through a recursive least squares (RLS) algorithm. The coefficients are arranged in a four-quadrant sub-band structure. The zero-tree coding algorithm is employed to quantize the coefficients. The system outperforms the embedded zero-tree wavelet scheme in a rate-distortion sense, with best perceptual quality for a given compression ratio.
{"title":"Image compression using auto-associative neural network and embedded zero-tree coding","authors":"S. Patnaik, R. Pal","doi":"10.1109/SPAWC.2001.923933","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923933","url":null,"abstract":"This paper presents an image compression method using auto-associative neural network and embedded zero-tree coding. The role of the neural network (NN) is to decompose the image stage by stage, which enables analysis similar to wavelet decomposition. This works on the principle of principal component extraction (PCE). Network training is achieved through a recursive least squares (RLS) algorithm. The coefficients are arranged in a four-quadrant sub-band structure. The zero-tree coding algorithm is employed to quantize the coefficients. The system outperforms the embedded zero-tree wavelet scheme in a rate-distortion sense, with best perceptual quality for a given compression ratio.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"30 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":"122375802","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.2001.923870
V. Ma, T. Ylamurto
The effect of IQ imbalance on the initial frequency offset estimation algorithm in an orthogonal frequency division multiplexing (OFDM) direct conversion receiver is studied. The impact of the phase and amplitude IQ imbalances and channel response on the frequency offset estimation is formulated for a flat channel case. Analysis of the IQ imbalance on the frequency offset estimation is provided and the results are presented in this paper. The results show that the frequency offset estimation algorithm generates an error in the estimated offset frequency with IQ imbalance and the error can be reduced by an appropriate choice of the correlation window length.
{"title":"Analysis of IQ imbalance on initial frequency offset estimation in direct down-conversion receivers","authors":"V. Ma, T. Ylamurto","doi":"10.1109/SPAWC.2001.923870","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923870","url":null,"abstract":"The effect of IQ imbalance on the initial frequency offset estimation algorithm in an orthogonal frequency division multiplexing (OFDM) direct conversion receiver is studied. The impact of the phase and amplitude IQ imbalances and channel response on the frequency offset estimation is formulated for a flat channel case. Analysis of the IQ imbalance on the frequency offset estimation is provided and the results are presented in this paper. The results show that the frequency offset estimation algorithm generates an error in the estimated offset frequency with IQ imbalance and the error can be reduced by an appropriate choice of the correlation window length.","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":"125762577","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.2001.923896
S. Matsufuji, K. Takatsukasa, Y. Watanabe, N. Kuroyanagi, N. Suehiro
This paper discusses quasi-orthogonal sequences consisting of real elements, whose periodic out-of-phase autocorrelation functions take zero except for a shift corresponding to the half period. It is shown that they can be formalized by use of the Fourier transform. As a special case, binary quasi-orthogonal sequences are found until period 196 from a conjecture for their constructions.
{"title":"Quasi-orthogonal sequences","authors":"S. Matsufuji, K. Takatsukasa, Y. Watanabe, N. Kuroyanagi, N. Suehiro","doi":"10.1109/SPAWC.2001.923896","DOIUrl":"https://doi.org/10.1109/SPAWC.2001.923896","url":null,"abstract":"This paper discusses quasi-orthogonal sequences consisting of real elements, whose periodic out-of-phase autocorrelation functions take zero except for a shift corresponding to the half period. It is shown that they can be formalized by use of the Fourier transform. As a special case, binary quasi-orthogonal sequences are found until period 196 from a conjecture for their constructions.","PeriodicalId":435867,"journal":{"name":"2001 IEEE Third Workshop on Signal Processing Advances in Wireless Communications (SPAWC'01). Workshop Proceedings (Cat. No.01EX471)","volume":"63 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":"132080045","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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