Pub Date : 1999-08-22DOI: 10.1109/PACRIM.1999.799589
S. Catreux, R. Kirlin, P. Driessen
The use of multiple element antennas-both transmitting and receiving-has great potential for increasing the capacity of wireless systems. The capacity is derived as a function of the eigenvalues of the channel matrix and computed for an "edge-excited cell" with 3 base sites and a subscriber terminal with a 3 element array, for line-of-sight channels. In an attempt to approach this capacity, we use a blind source separation technique at the receiver. We show that the multiple-input multiple-output system, implemented with such innovative signal processing, offers great enhanced capacity compared to conventional single-input single-output (SISO) systems.
{"title":"Capacity and performance of multiple-input multiple-output wireless systems in a cellular context","authors":"S. Catreux, R. Kirlin, P. Driessen","doi":"10.1109/PACRIM.1999.799589","DOIUrl":"https://doi.org/10.1109/PACRIM.1999.799589","url":null,"abstract":"The use of multiple element antennas-both transmitting and receiving-has great potential for increasing the capacity of wireless systems. The capacity is derived as a function of the eigenvalues of the channel matrix and computed for an \"edge-excited cell\" with 3 base sites and a subscriber terminal with a 3 element array, for line-of-sight channels. In an attempt to approach this capacity, we use a blind source separation technique at the receiver. We show that the multiple-input multiple-output system, implemented with such innovative signal processing, offers great enhanced capacity compared to conventional single-input single-output (SISO) systems.","PeriodicalId":176763,"journal":{"name":"1999 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing (PACRIM 1999). Conference Proceedings (Cat. No.99CH36368)","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124492967","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 : 1999-08-22DOI: 10.1109/PACRIM.1999.799590
J.Y. Kim, Wan Choi
In this paper, a new multiuser detection scheme combining decorrelating detection and multicarrier transmission is proposed and analyzed in a frequency-selective Rayleigh fading channel. The bit error probability and asymptotic multiuser efficiency are derived and compared for the proposed and the conventional decorrelating detector scheme. From the numerical results, it is shown that the proposed scheme achieves better BER performance and lower computational complexity than the conventional decorrelating detector. It is also shown that the proposed scheme is more robust than the conventional scheme when there is partial narrowband interference, and alleviates near-far problem more effectively.
{"title":"Performance of a multicarrier decorrelating multiuser receiver for a DS/CDMA system","authors":"J.Y. Kim, Wan Choi","doi":"10.1109/PACRIM.1999.799590","DOIUrl":"https://doi.org/10.1109/PACRIM.1999.799590","url":null,"abstract":"In this paper, a new multiuser detection scheme combining decorrelating detection and multicarrier transmission is proposed and analyzed in a frequency-selective Rayleigh fading channel. The bit error probability and asymptotic multiuser efficiency are derived and compared for the proposed and the conventional decorrelating detector scheme. From the numerical results, it is shown that the proposed scheme achieves better BER performance and lower computational complexity than the conventional decorrelating detector. It is also shown that the proposed scheme is more robust than the conventional scheme when there is partial narrowband interference, and alleviates near-far problem more effectively.","PeriodicalId":176763,"journal":{"name":"1999 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing (PACRIM 1999). Conference Proceedings (Cat. No.99CH36368)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115900345","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 : 1999-08-22DOI: 10.1109/PACRIM.1999.799601
X.F. Wang, W. Lu, A. Antoniou
Several design criteria for time-domain equalization in discrete-multitone-based asymmetric digital subscriber line systems are studied. A new criterion that maximizes the signal-to-noise ratio regardless of the profile of bandwidth occupancy is proposed. Based on the new criterion, a procedure for optimizing the bandwidth occupancy is developed. The new criterion is shown to track the change in bandwidth occupancy and thus leads to significant performance gain when combined with bandwidth optimization. Simulations are carried out to quantify the effects of the new criterion and its associated bandwidth optimization on the performance of the system.
{"title":"Equalization for partially bandwidth-occupied multicarrier transceivers","authors":"X.F. Wang, W. Lu, A. Antoniou","doi":"10.1109/PACRIM.1999.799601","DOIUrl":"https://doi.org/10.1109/PACRIM.1999.799601","url":null,"abstract":"Several design criteria for time-domain equalization in discrete-multitone-based asymmetric digital subscriber line systems are studied. A new criterion that maximizes the signal-to-noise ratio regardless of the profile of bandwidth occupancy is proposed. Based on the new criterion, a procedure for optimizing the bandwidth occupancy is developed. The new criterion is shown to track the change in bandwidth occupancy and thus leads to significant performance gain when combined with bandwidth optimization. Simulations are carried out to quantify the effects of the new criterion and its associated bandwidth optimization on the performance of the system.","PeriodicalId":176763,"journal":{"name":"1999 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing (PACRIM 1999). Conference Proceedings (Cat. No.99CH36368)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128027117","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 : 1999-08-22DOI: 10.1109/PACRIM.1999.799541
Sangjin Hong, W. Stark
A high throughput energy efficient digital matched filter design method for low power communication systems is presented. The filter coefficients are designed to optimize spectral concentration in the transmission bandwidth of the channel with zero intersymbol interference while minimizing the energy dissipation. The optimum matched filter coefficients are searched from the discrete powers-of-two number space and each of the coefficients are restricted to contain at most a finite number of nonzero bits to reduce power dissipation and to increase throughput.
{"title":"Performance driven coefficient optimization for high throughput energy efficient digital matched filter design","authors":"Sangjin Hong, W. Stark","doi":"10.1109/PACRIM.1999.799541","DOIUrl":"https://doi.org/10.1109/PACRIM.1999.799541","url":null,"abstract":"A high throughput energy efficient digital matched filter design method for low power communication systems is presented. The filter coefficients are designed to optimize spectral concentration in the transmission bandwidth of the channel with zero intersymbol interference while minimizing the energy dissipation. The optimum matched filter coefficients are searched from the discrete powers-of-two number space and each of the coefficients are restricted to contain at most a finite number of nonzero bits to reduce power dissipation and to increase throughput.","PeriodicalId":176763,"journal":{"name":"1999 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing (PACRIM 1999). Conference Proceedings (Cat. No.99CH36368)","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124951932","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 : 1999-08-22DOI: 10.1109/PACRIM.1999.799585
J. Monera-Llorca, W. Lu, V. Bhargava
A wavelet-packet-based family of user signatures for asynchronous CDMA systems is investigated. These signatures are of non-binary nature and are generated by the application of the inverse wavelet packet transform. Through numerical optimization, we obtain the wavelet filter which minimizes the crosscorrelation among signatures for different user configuration systems. The improvement in performance is especially notable in the oversaturated system scenario. Finally, we comment briefly on the topics of bandwidth efficiency, user privacy, and implementation.
{"title":"Wavelet-packet-based signatures for asynchronous CDMA systems","authors":"J. Monera-Llorca, W. Lu, V. Bhargava","doi":"10.1109/PACRIM.1999.799585","DOIUrl":"https://doi.org/10.1109/PACRIM.1999.799585","url":null,"abstract":"A wavelet-packet-based family of user signatures for asynchronous CDMA systems is investigated. These signatures are of non-binary nature and are generated by the application of the inverse wavelet packet transform. Through numerical optimization, we obtain the wavelet filter which minimizes the crosscorrelation among signatures for different user configuration systems. The improvement in performance is especially notable in the oversaturated system scenario. Finally, we comment briefly on the topics of bandwidth efficiency, user privacy, and implementation.","PeriodicalId":176763,"journal":{"name":"1999 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing (PACRIM 1999). Conference Proceedings (Cat. No.99CH36368)","volume":"52 194 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126721517","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 : 1999-08-22DOI: 10.1109/PACRIM.1999.799491
Xiaojing Yuan, B. Soong, Liren Zhang
The ABR service is mainly designed for data transmission in the ATM network and ABR congestion control is an active research area. We propose a control algorithm that is simple to implement and it does not require much network resource for its operation. Both the load factor and the change of queue length are incorporated in the control, based upon which traffic is adjusted. In underload, the increase in the source rate depends on the load factor of the ABR. The lower the load factor, the faster the source rate is increased. When the load approaches the target level, the traffic is increased very slowly. Under congestion, the suppression of the source rate is determined by the increasing queue rate. An exponential average is provided as the approximation to the fair share. Simulation shows that the algorithm exhibits fairness and stability.
{"title":"ABR rate-based control scheme with background VBR traffic","authors":"Xiaojing Yuan, B. Soong, Liren Zhang","doi":"10.1109/PACRIM.1999.799491","DOIUrl":"https://doi.org/10.1109/PACRIM.1999.799491","url":null,"abstract":"The ABR service is mainly designed for data transmission in the ATM network and ABR congestion control is an active research area. We propose a control algorithm that is simple to implement and it does not require much network resource for its operation. Both the load factor and the change of queue length are incorporated in the control, based upon which traffic is adjusted. In underload, the increase in the source rate depends on the load factor of the ABR. The lower the load factor, the faster the source rate is increased. When the load approaches the target level, the traffic is increased very slowly. Under congestion, the suppression of the source rate is determined by the increasing queue rate. An exponential average is provided as the approximation to the fair share. Simulation shows that the algorithm exhibits fairness and stability.","PeriodicalId":176763,"journal":{"name":"1999 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing (PACRIM 1999). Conference Proceedings (Cat. No.99CH36368)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114153949","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 : 1999-08-22DOI: 10.1109/PACRIM.1999.799581
Y. Zhang, M. Zeytinoglu
Adaptive block processing is a technique suitable for compressing non-stationary signals, where input blocks are first decomposed by a filterbank into subband signals. These subband signals are in turn analyzed to extract the time-varying signal parameters. We can optimize a given subband coding algorithm by introducing time-varying filterbanks, where for each input block we alter the structure of the decomposition filterbank such that a particular coding criteria is optimized. In this paper, we use time-varying filterbanks as a basis for adaptive subband coding. In particular, we analyze the relationship between adaptive block subband coding and time-varying filterbanks. We introduced a method for deriving boundary filters and entry/exit filters for the synthesis filterbanks. We show that conventional design techniques for the time-varying filterbanks exhibit many characteristics that make them less than ideal candidates for adaptive signal decomposition.
{"title":"Block subband coding and time-varying filterbanks","authors":"Y. Zhang, M. Zeytinoglu","doi":"10.1109/PACRIM.1999.799581","DOIUrl":"https://doi.org/10.1109/PACRIM.1999.799581","url":null,"abstract":"Adaptive block processing is a technique suitable for compressing non-stationary signals, where input blocks are first decomposed by a filterbank into subband signals. These subband signals are in turn analyzed to extract the time-varying signal parameters. We can optimize a given subband coding algorithm by introducing time-varying filterbanks, where for each input block we alter the structure of the decomposition filterbank such that a particular coding criteria is optimized. In this paper, we use time-varying filterbanks as a basis for adaptive subband coding. In particular, we analyze the relationship between adaptive block subband coding and time-varying filterbanks. We introduced a method for deriving boundary filters and entry/exit filters for the synthesis filterbanks. We show that conventional design techniques for the time-varying filterbanks exhibit many characteristics that make them less than ideal candidates for adaptive signal decomposition.","PeriodicalId":176763,"journal":{"name":"1999 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing (PACRIM 1999). Conference Proceedings (Cat. No.99CH36368)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121839927","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 : 1999-08-22DOI: 10.1109/PACRIM.1999.799507
N. Law, W. Siu, Degan Feng
A non-iterative wavelet-based algorithm was proposed to reduce the ringing artifacts associated with a lossy compressed image. The proposed algorithm is based on the fact that increases in magnitude of the quantized wavelet coefficients lead to decreases in visual smoothness. Thus a shrinkage algorithm is applied to maintain visual smoothness. The proposed algorithm is, however, adaptive in nature, in which the amount of shrinkage depends on edge strength, region activity and compression ratio. Experimental results have confirmed that the adaptive algorithm could suppress the ringing artifacts and improve visual smoothness, especially around edges where ringing is severe.
{"title":"Suppression of ringing artifacts with an adaptive shrinkage algorithm","authors":"N. Law, W. Siu, Degan Feng","doi":"10.1109/PACRIM.1999.799507","DOIUrl":"https://doi.org/10.1109/PACRIM.1999.799507","url":null,"abstract":"A non-iterative wavelet-based algorithm was proposed to reduce the ringing artifacts associated with a lossy compressed image. The proposed algorithm is based on the fact that increases in magnitude of the quantized wavelet coefficients lead to decreases in visual smoothness. Thus a shrinkage algorithm is applied to maintain visual smoothness. The proposed algorithm is, however, adaptive in nature, in which the amount of shrinkage depends on edge strength, region activity and compression ratio. Experimental results have confirmed that the adaptive algorithm could suppress the ringing artifacts and improve visual smoothness, especially around edges where ringing is severe.","PeriodicalId":176763,"journal":{"name":"1999 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing (PACRIM 1999). Conference Proceedings (Cat. No.99CH36368)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123088642","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 : 1999-08-22DOI: 10.1109/PACRIM.1999.799548
Chen Chau Chu, H. Alnuweiri
This paper proposes a multicast packet switching architecture that employs input/output buffers, and internal bandwidth expansion to reduce blocking substantially. Internal buffers enhance switch robustness under transient bursty traffic conditions. The switch regulates packet loss and delay using link-capacity back-pressure in conjunction with dynamic random early detection (or D-RED) algorithm. Because of these features the proposed switch exhibits excellent performance under multicast (as well as unicast) traffic even under heavy bursty traffic loads. Simulation studies show that the proposed architecture with its enhanced flow control features has superior packet loss performance compared to many other switch classes especially under multicast and bursty traffic.
{"title":"Performance evaluation of a multicast packet switch employing dynamic random early detection","authors":"Chen Chau Chu, H. Alnuweiri","doi":"10.1109/PACRIM.1999.799548","DOIUrl":"https://doi.org/10.1109/PACRIM.1999.799548","url":null,"abstract":"This paper proposes a multicast packet switching architecture that employs input/output buffers, and internal bandwidth expansion to reduce blocking substantially. Internal buffers enhance switch robustness under transient bursty traffic conditions. The switch regulates packet loss and delay using link-capacity back-pressure in conjunction with dynamic random early detection (or D-RED) algorithm. Because of these features the proposed switch exhibits excellent performance under multicast (as well as unicast) traffic even under heavy bursty traffic loads. Simulation studies show that the proposed architecture with its enhanced flow control features has superior packet loss performance compared to many other switch classes especially under multicast and bursty traffic.","PeriodicalId":176763,"journal":{"name":"1999 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing (PACRIM 1999). Conference Proceedings (Cat. No.99CH36368)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133215409","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 : 1999-08-22DOI: 10.1109/PACRIM.1999.799567
Chang Nian Zhang, Ming Zhao, M. Wang
This paper focuses on phase analysis to explore the potential of single neuron local arithmetic and logic operations on input conductances. The analysis is based on a rational function model of local spatial summation with the equivalent circuits for steady-state membrane potentials. The prototypes of arithmetic and logic operations are then constructed with their input and output range.
{"title":"Multi-mode single neuron arithmetics and logics","authors":"Chang Nian Zhang, Ming Zhao, M. Wang","doi":"10.1109/PACRIM.1999.799567","DOIUrl":"https://doi.org/10.1109/PACRIM.1999.799567","url":null,"abstract":"This paper focuses on phase analysis to explore the potential of single neuron local arithmetic and logic operations on input conductances. The analysis is based on a rational function model of local spatial summation with the equivalent circuits for steady-state membrane potentials. The prototypes of arithmetic and logic operations are then constructed with their input and output range.","PeriodicalId":176763,"journal":{"name":"1999 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing (PACRIM 1999). Conference Proceedings (Cat. No.99CH36368)","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117159281","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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