Pub Date : 1998-09-02DOI: 10.1109/ISSSTA.1998.726195
A. Grant
The goal of this paper is to find training sequences, that when used in conjunction with an efficient estimator for a discrete-time multipath channel with additive white Gaussian noise yield the least possible mean square error in the channel estimate. In order to achieve this goal, we use the Cramer-Rao bound.
{"title":"Optimal sequences for efficient estimation of multipath channels","authors":"A. Grant","doi":"10.1109/ISSSTA.1998.726195","DOIUrl":"https://doi.org/10.1109/ISSSTA.1998.726195","url":null,"abstract":"The goal of this paper is to find training sequences, that when used in conjunction with an efficient estimator for a discrete-time multipath channel with additive white Gaussian noise yield the least possible mean square error in the channel estimate. In order to achieve this goal, we use the Cramer-Rao bound.","PeriodicalId":116377,"journal":{"name":"1988 IEEE 5th International Symposium on Spread Spectrum Techniques and Applications - Proceedings. Spread Technology to Africa (Cat. No.98TH8333)","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125771698","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 : 1998-09-02DOI: 10.1109/ISSSTA.1998.723817
K. T. Tan, R. Liyanapathirana, K. Ngan
In this paper we have analysed the error performance of both the sequency majority multiplexing (SMM) and the concatenated sequency majority multiplexing (CSMM) schemes in the traditional AWGN channel and in a selection of frequency-nonselective, slowly fading channels. Our analysis extended the current knowledge on how these sequency multiplexing schemes perform in fading channels-an environment pertinent to the operations of wireless communication systems. We also looked at the improved performance of the CSMM scheme and revealed how such a simple improvement can further extend the performance gains of the SMM scheme by 2 to 3 folds. Our analysis highlighted a few attractive features of both the SMM and CSMM schemes which make them possible contenders for regulating multiple access in a multi-carrier spread spectrum scenario.
{"title":"Error probabilities for sequency majority multiplexing in frequency-nonselective, slowly fading channels. 2. Numerical analysis","authors":"K. T. Tan, R. Liyanapathirana, K. Ngan","doi":"10.1109/ISSSTA.1998.723817","DOIUrl":"https://doi.org/10.1109/ISSSTA.1998.723817","url":null,"abstract":"In this paper we have analysed the error performance of both the sequency majority multiplexing (SMM) and the concatenated sequency majority multiplexing (CSMM) schemes in the traditional AWGN channel and in a selection of frequency-nonselective, slowly fading channels. Our analysis extended the current knowledge on how these sequency multiplexing schemes perform in fading channels-an environment pertinent to the operations of wireless communication systems. We also looked at the improved performance of the CSMM scheme and revealed how such a simple improvement can further extend the performance gains of the SMM scheme by 2 to 3 folds. Our analysis highlighted a few attractive features of both the SMM and CSMM schemes which make them possible contenders for regulating multiple access in a multi-carrier spread spectrum scenario.","PeriodicalId":116377,"journal":{"name":"1988 IEEE 5th International Symposium on Spread Spectrum Techniques and Applications - Proceedings. Spread Technology to Africa (Cat. No.98TH8333)","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122881157","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 : 1998-09-02DOI: 10.1109/ISSSTA.1998.726251
R. Prasad, T. Ojanpera
This paper presents an overview of CDMA and discusses the main features of the future air interface access schemes namely WCDMA and CDMA2000, for IMT-2000/UMTS. Multiple access schemes and CDMA classification are introduced. CDMA past, present and future activities are presented, and the concepts and elements of CDMA are explained. Wideband CDMA schemes are also presented and conclusions are given.
{"title":"A survey on CDMA: evolution towards wideband CDMA","authors":"R. Prasad, T. Ojanpera","doi":"10.1109/ISSSTA.1998.726251","DOIUrl":"https://doi.org/10.1109/ISSSTA.1998.726251","url":null,"abstract":"This paper presents an overview of CDMA and discusses the main features of the future air interface access schemes namely WCDMA and CDMA2000, for IMT-2000/UMTS. Multiple access schemes and CDMA classification are introduced. CDMA past, present and future activities are presented, and the concepts and elements of CDMA are explained. Wideband CDMA schemes are also presented and conclusions are given.","PeriodicalId":116377,"journal":{"name":"1988 IEEE 5th International Symposium on Spread Spectrum Techniques and Applications - Proceedings. Spread Technology to Africa (Cat. No.98TH8333)","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126837219","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 : 1998-09-02DOI: 10.1109/ISSSTA.1998.723828
L. Sabel
We present a fully digital delay locked loop (DLL) which incorporates low complexity complex-signal phase detector and non-linear NCO components. The NCO is based on a pulse position modulation (PPM) method which is implemented using a fixed time-precision interpolator. Unlike the conventional DLL which uses a linear VCO, the NCO used here is highly non-linear. The DLL structure is described and the performance of the MA-ABS phase detector is presented. The closed loop performance is analysed for the case of a second order loop filter and the results of digital simulations are presented.
{"title":"On the performance of a low complexity baseband 2nd order delay locked loop incorporating a non-linear NCO","authors":"L. Sabel","doi":"10.1109/ISSSTA.1998.723828","DOIUrl":"https://doi.org/10.1109/ISSSTA.1998.723828","url":null,"abstract":"We present a fully digital delay locked loop (DLL) which incorporates low complexity complex-signal phase detector and non-linear NCO components. The NCO is based on a pulse position modulation (PPM) method which is implemented using a fixed time-precision interpolator. Unlike the conventional DLL which uses a linear VCO, the NCO used here is highly non-linear. The DLL structure is described and the performance of the MA-ABS phase detector is presented. The closed loop performance is analysed for the case of a second order loop filter and the results of digital simulations are presented.","PeriodicalId":116377,"journal":{"name":"1988 IEEE 5th International Symposium on Spread Spectrum Techniques and Applications - Proceedings. Spread Technology to Africa (Cat. No.98TH8333)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130152508","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 : 1998-09-02DOI: 10.1109/ISSSTA.1998.726201
A. Widodo, Takaaki
There have been intensive studies on inter-vehicle communication systems with the purpose to increase the traffic safety. A new inter-vehicle communication system using SS techniques is proposed. This paper discusses the conceptual model and system configuration of the proposed system. This paper also shows pre-examinations of the proposed system by using an autonomous traffic flow simulator including inter-vehicle communications. It is shown that the traffic safety can be improved, by using the inter-vehicle communication system.
{"title":"A new inter-vehicle communication system for intelligent transport systems and an autonomous traffic flow simulator","authors":"A. Widodo, Takaaki","doi":"10.1109/ISSSTA.1998.726201","DOIUrl":"https://doi.org/10.1109/ISSSTA.1998.726201","url":null,"abstract":"There have been intensive studies on inter-vehicle communication systems with the purpose to increase the traffic safety. A new inter-vehicle communication system using SS techniques is proposed. This paper discusses the conceptual model and system configuration of the proposed system. This paper also shows pre-examinations of the proposed system by using an autonomous traffic flow simulator including inter-vehicle communications. It is shown that the traffic safety can be improved, by using the inter-vehicle communication system.","PeriodicalId":116377,"journal":{"name":"1988 IEEE 5th International Symposium on Spread Spectrum Techniques and Applications - Proceedings. Spread Technology to Africa (Cat. No.98TH8333)","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128619598","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 : 1998-09-02DOI: 10.1109/ISSSTA.1998.726246
R. Silva, A. Gameiro
We deal with wireless local loop (WLL) systems using spread spectrum techniques to provide integrated services digital networks (ISDN) local access. We consider the dimensioning of a base station intended to serve various ISDN subscribers. The connection between subscribers and base station is achieved via the atmospheric channel and the transmission technique used is direct sequence spread spectrum (DS-SS). An expression that permits the calculation of the maximum number of users that a base station can serve in providing the desired quality of service (QoS) and the mean traffic per user is derived. Based on this formulation we present numerical results, on the QoS for values of the bit error probability required by an ISDN and the typical mean traffic of this kind of application.
{"title":"Dimensioning of spread spectrum systems for ISDN","authors":"R. Silva, A. Gameiro","doi":"10.1109/ISSSTA.1998.726246","DOIUrl":"https://doi.org/10.1109/ISSSTA.1998.726246","url":null,"abstract":"We deal with wireless local loop (WLL) systems using spread spectrum techniques to provide integrated services digital networks (ISDN) local access. We consider the dimensioning of a base station intended to serve various ISDN subscribers. The connection between subscribers and base station is achieved via the atmospheric channel and the transmission technique used is direct sequence spread spectrum (DS-SS). An expression that permits the calculation of the maximum number of users that a base station can serve in providing the desired quality of service (QoS) and the mean traffic per user is derived. Based on this formulation we present numerical results, on the QoS for values of the bit error probability required by an ISDN and the typical mean traffic of this kind of application.","PeriodicalId":116377,"journal":{"name":"1988 IEEE 5th International Symposium on Spread Spectrum Techniques and Applications - Proceedings. Spread Technology to Africa (Cat. No.98TH8333)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129120772","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 : 1998-09-02DOI: 10.1109/ISSSTA.1998.722500
R. De Gaudenzi, F. Giannetti, M. Luise, J. Romero-García
This paper presents an enhanced version of the previously-proposed blind adaptive interference detector (BAID) for direct-sequence code division multiple access (DS-CDMA) transmission. Such a new detector, named extended complex BAID (EC-BAID), reveals resistance to a possible large frequency shift (e.g., Doppler shift) on interfering carriers, and features invariance to the phase error on the useful channel's carrier. The EC-BAID is also shown to bear a sensitivity to residual carrier frequency errors on the desired channel which is lower by three orders of magnitude with respect to the data-aided minimum mean square error (DA-MMSE) receiver. The performance of the EC-BAID was numerically assessed by computer simulations and successfully compared to analytical findings under a variety of system configurations. It turned out that the EC-BAID, despite its blind operating mode, bears an uncoded symbol error rate (SER) performance that closely approaches the DA-MMSEs. Finally, a few implementation aspects of the new interference-mitigating detector are also discussed.
{"title":"A frequency error resistant blind interference-mitigating CDMA detector","authors":"R. De Gaudenzi, F. Giannetti, M. Luise, J. Romero-García","doi":"10.1109/ISSSTA.1998.722500","DOIUrl":"https://doi.org/10.1109/ISSSTA.1998.722500","url":null,"abstract":"This paper presents an enhanced version of the previously-proposed blind adaptive interference detector (BAID) for direct-sequence code division multiple access (DS-CDMA) transmission. Such a new detector, named extended complex BAID (EC-BAID), reveals resistance to a possible large frequency shift (e.g., Doppler shift) on interfering carriers, and features invariance to the phase error on the useful channel's carrier. The EC-BAID is also shown to bear a sensitivity to residual carrier frequency errors on the desired channel which is lower by three orders of magnitude with respect to the data-aided minimum mean square error (DA-MMSE) receiver. The performance of the EC-BAID was numerically assessed by computer simulations and successfully compared to analytical findings under a variety of system configurations. It turned out that the EC-BAID, despite its blind operating mode, bears an uncoded symbol error rate (SER) performance that closely approaches the DA-MMSEs. Finally, a few implementation aspects of the new interference-mitigating detector are also discussed.","PeriodicalId":116377,"journal":{"name":"1988 IEEE 5th International Symposium on Spread Spectrum Techniques and Applications - Proceedings. Spread Technology to Africa (Cat. No.98TH8333)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129292796","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 : 1998-09-02DOI: 10.1109/ISSSTA.1998.723858
F. Chin, Bo Lan, C. Ko
The uplink capacity of a variable rate CDMA system with antenna array at the base-station is studied. Presented is the performance analysis for two classes of users, i.e., mixture of data users and voice users defined by their bandwidth and fidelity requirements in a multicell CDMA cellular system. In this paper, the effect of path loss, Rayleigh fading, log-normal shadowing, together with multiple access interference and thermal noise are considered. Simulation results are also presented.
{"title":"Uplink capacity of variable rate CDMA using antenna array","authors":"F. Chin, Bo Lan, C. Ko","doi":"10.1109/ISSSTA.1998.723858","DOIUrl":"https://doi.org/10.1109/ISSSTA.1998.723858","url":null,"abstract":"The uplink capacity of a variable rate CDMA system with antenna array at the base-station is studied. Presented is the performance analysis for two classes of users, i.e., mixture of data users and voice users defined by their bandwidth and fidelity requirements in a multicell CDMA cellular system. In this paper, the effect of path loss, Rayleigh fading, log-normal shadowing, together with multiple access interference and thermal noise are considered. Simulation results are also presented.","PeriodicalId":116377,"journal":{"name":"1988 IEEE 5th International Symposium on Spread Spectrum Techniques and Applications - Proceedings. Spread Technology to Africa (Cat. No.98TH8333)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116875878","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 : 1998-09-02DOI: 10.1109/ISSSTA.1998.723838
G. Wetzker, U. Kaage, F. Jondral
To evaluate the performance of modern modulation techniques suited for time-variant multipath propagation, it is necessary to simulate such channels by computer models. A time-variant multipath channel distorts a transmission link by frequency and time dispersion. While the simulation of time dispersion can be accomplished by a finite tapped delay line, the simulation of the frequency dispersion depends on the time variations of the channel, which are typically very slow compared to the sampling interval of the simulation and therefore, difficult to simulate. Before a new method for the simulation of Doppler spectra is presented, the theory of channel modelling and Doppler spectra is reviewed and known methods for the simulation of Doppler spectra and their disadvantages are discussed.
{"title":"A simulation method for Doppler spectra","authors":"G. Wetzker, U. Kaage, F. Jondral","doi":"10.1109/ISSSTA.1998.723838","DOIUrl":"https://doi.org/10.1109/ISSSTA.1998.723838","url":null,"abstract":"To evaluate the performance of modern modulation techniques suited for time-variant multipath propagation, it is necessary to simulate such channels by computer models. A time-variant multipath channel distorts a transmission link by frequency and time dispersion. While the simulation of time dispersion can be accomplished by a finite tapped delay line, the simulation of the frequency dispersion depends on the time variations of the channel, which are typically very slow compared to the sampling interval of the simulation and therefore, difficult to simulate. Before a new method for the simulation of Doppler spectra is presented, the theory of channel modelling and Doppler spectra is reviewed and known methods for the simulation of Doppler spectra and their disadvantages are discussed.","PeriodicalId":116377,"journal":{"name":"1988 IEEE 5th International Symposium on Spread Spectrum Techniques and Applications - Proceedings. Spread Technology to Africa (Cat. No.98TH8333)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117065370","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 : 1998-09-02DOI: 10.1109/ISSSTA.1998.723853
Y.J. Guo, S. Vadgama, M. Davies, J. Khalab, M. Zarri, D. Spink
A decision directed adaptive antenna for the uplink of CDMA cellular systems has been presented. The performance of the adaptive antenna in various scenarios has been studied. It is shown that the adaptive antenna significantly outperforms the steering beam when SNR is large, the number of active users is moderate, and the active users are clustered instead of being uniformly distributed. The performance of the adaptive beamformer becomes similar to that of the steering beam when there are a large number of randomly distributed active users in the sector. It is proved that a combination of the adaptive array antenna and diversity is a powerful technique to achieve low BER in the third generation (3G) CDMA cellular mobile communications systems.
{"title":"An adaptive antenna for CDMA","authors":"Y.J. Guo, S. Vadgama, M. Davies, J. Khalab, M. Zarri, D. Spink","doi":"10.1109/ISSSTA.1998.723853","DOIUrl":"https://doi.org/10.1109/ISSSTA.1998.723853","url":null,"abstract":"A decision directed adaptive antenna for the uplink of CDMA cellular systems has been presented. The performance of the adaptive antenna in various scenarios has been studied. It is shown that the adaptive antenna significantly outperforms the steering beam when SNR is large, the number of active users is moderate, and the active users are clustered instead of being uniformly distributed. The performance of the adaptive beamformer becomes similar to that of the steering beam when there are a large number of randomly distributed active users in the sector. It is proved that a combination of the adaptive array antenna and diversity is a powerful technique to achieve low BER in the third generation (3G) CDMA cellular mobile communications systems.","PeriodicalId":116377,"journal":{"name":"1988 IEEE 5th International Symposium on Spread Spectrum Techniques and Applications - Proceedings. Spread Technology to Africa (Cat. No.98TH8333)","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117162050","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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