Pub Date : 1998-09-02DOI: 10.1109/ISSSTA.1998.722522
M. Lotter, P. van Rooyen
This paper describes a novel adaptive virtual token ring (AVTR) multiple access protocol. The random access method presented is shown to be a spatial derivative of a token ring network. The operation of the system is described with reference to its application in cellular networks capable of providing a range of heterogenous services such as voice and data. Specifically, it is shown how the system can easily be used to perform dynamic quality of service (QoS) management with little additional hardware resources required.
{"title":"AVTR-a random access method for mobile networks","authors":"M. Lotter, P. van Rooyen","doi":"10.1109/ISSSTA.1998.722522","DOIUrl":"https://doi.org/10.1109/ISSSTA.1998.722522","url":null,"abstract":"This paper describes a novel adaptive virtual token ring (AVTR) multiple access protocol. The random access method presented is shown to be a spatial derivative of a token ring network. The operation of the system is described with reference to its application in cellular networks capable of providing a range of heterogenous services such as voice and data. Specifically, it is shown how the system can easily be used to perform dynamic quality of service (QoS) management with little additional hardware resources required.","PeriodicalId":116377,"journal":{"name":"1988 IEEE 5th International Symposium on Spread Spectrum Techniques and Applications - Proceedings. Spread Technology to Africa (Cat. No.98TH8333)","volume":"55 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":"124410172","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.1998.723810
K. Mohamed-Pour
To combat the effect of performance degradation due to the multipath fading, diversity techniques are known as the most advantageous procedure without increasing either the transmitted power or the bandwidth requirement. Combination of the coding, which is used for power-limited and band-limited channels, and diversity is a new aspect to exploit both for such channels as mobile radio. Some new combined coding-diversity (CCD) schemes are introduced, and simulated over uncorrelated Rayleigh fading which trellis detection and decoding simultaneously have been used.
{"title":"Combined coding-diversity (CCD) schemes for fading channels","authors":"K. Mohamed-Pour","doi":"10.1109/ISSSTA.1998.723810","DOIUrl":"https://doi.org/10.1109/ISSSTA.1998.723810","url":null,"abstract":"To combat the effect of performance degradation due to the multipath fading, diversity techniques are known as the most advantageous procedure without increasing either the transmitted power or the bandwidth requirement. Combination of the coding, which is used for power-limited and band-limited channels, and diversity is a new aspect to exploit both for such channels as mobile radio. Some new combined coding-diversity (CCD) schemes are introduced, and simulated over uncorrelated Rayleigh fading which trellis detection and decoding simultaneously have been used.","PeriodicalId":116377,"journal":{"name":"1988 IEEE 5th International Symposium on Spread Spectrum Techniques and Applications - Proceedings. Spread Technology to Africa (Cat. No.98TH8333)","volume":"94 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":"133723177","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.1998.723842
K. Hooli, I. Oppermann
This paper examines the effect of signal quantization on the performance of an adaptive LMMSE DS-CDMA receiver in the up-link of low mobility, high data rate wireless local loop (WLL) application. The baseband receiver considered is the LMS-LMMSE receiver which includes the finite quantization of the incoming signal. Both AWGN channel and multipath channel models based on actual channel measurements are used in the computer simulations. Also the effect of imperfect power control on the signal quantization is considered. It is shown that the degradation in the performance of the receiver is relatively insignificant with practical levels of quantization.
{"title":"Effect of signal quantization on the performance of LMMSE receiver in WLL channels","authors":"K. Hooli, I. Oppermann","doi":"10.1109/ISSSTA.1998.723842","DOIUrl":"https://doi.org/10.1109/ISSSTA.1998.723842","url":null,"abstract":"This paper examines the effect of signal quantization on the performance of an adaptive LMMSE DS-CDMA receiver in the up-link of low mobility, high data rate wireless local loop (WLL) application. The baseband receiver considered is the LMS-LMMSE receiver which includes the finite quantization of the incoming signal. Both AWGN channel and multipath channel models based on actual channel measurements are used in the computer simulations. Also the effect of imperfect power control on the signal quantization is considered. It is shown that the degradation in the performance of the receiver is relatively insignificant with practical levels of quantization.","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":"131222268","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.1998.723866
R. Tanner, D. Cruickshank
This paper presents a Mahalanobis based radial basis function network (RBF) receiver structure with reduced complexity. It is also illustrated, how the RBF receiver could be employed as a multiuser detector. The RBF structure has superior performance over linear receiver structures and is equivalent to MLSD in an AWGN channel. However, a drawback is its complexity in multipath channels. Ideas from pattern recognition are exploited to reduce its complexity for multipath scenarios with little performance loss.
{"title":"RBF based receivers for DS-CDMA with reduced complexity","authors":"R. Tanner, D. Cruickshank","doi":"10.1109/ISSSTA.1998.723866","DOIUrl":"https://doi.org/10.1109/ISSSTA.1998.723866","url":null,"abstract":"This paper presents a Mahalanobis based radial basis function network (RBF) receiver structure with reduced complexity. It is also illustrated, how the RBF receiver could be employed as a multiuser detector. The RBF structure has superior performance over linear receiver structures and is equivalent to MLSD in an AWGN channel. However, a drawback is its complexity in multipath channels. Ideas from pattern recognition are exploited to reduce its complexity for multipath scenarios with little performance loss.","PeriodicalId":116377,"journal":{"name":"1988 IEEE 5th International Symposium on Spread Spectrum Techniques and Applications - Proceedings. Spread Technology to Africa (Cat. No.98TH8333)","volume":"83 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":"132167379","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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