Pub Date : 2000-05-15DOI: 10.1109/VETECS.2000.851471
Chunrui Zhang, M. Siyal
Image processing techniques are now considered flexible and practical for collecting and analyzing road traffic data. However, traditional image processing techniques based on grey scale images have not provided good results. In this paper we introduce a new technique, which is based on colour motion segmentation and split-merge segmentation approaches. First we use motion segmentation to determine the rough position of moving vehicles in a sequence of images. Then we apply the split-merge segmentation on the colour images. In this way we need not process the whole image, which saves computation time. Instead of determining the threshold value manually, which is the case in most vision-based traffic systems, we use an adaptive threshold to automatically choose the threshold value for split-merge method. We also classify the vehicle into 4 categories based on the feature of contour. The experiment results show that this method is quite promising.
{"title":"A new segmentation technique for classification of moving vehicles","authors":"Chunrui Zhang, M. Siyal","doi":"10.1109/VETECS.2000.851471","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851471","url":null,"abstract":"Image processing techniques are now considered flexible and practical for collecting and analyzing road traffic data. However, traditional image processing techniques based on grey scale images have not provided good results. In this paper we introduce a new technique, which is based on colour motion segmentation and split-merge segmentation approaches. First we use motion segmentation to determine the rough position of moving vehicles in a sequence of images. Then we apply the split-merge segmentation on the colour images. In this way we need not process the whole image, which saves computation time. Instead of determining the threshold value manually, which is the case in most vision-based traffic systems, we use an adaptive threshold to automatically choose the threshold value for split-merge method. We also classify the vehicle into 4 categories based on the feature of contour. The experiment results show that this method is quite promising.","PeriodicalId":318880,"journal":{"name":"VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130219339","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 : 2000-05-15DOI: 10.1109/VETECS.2000.851587
Paulo Cardieri, Theodore S. Rappaport
Schwartz and Yeh's method (1982) and Wilkinson's method are widely used to compute the moments of the total co-channel interference in wireless communication, usually modeled as the sum of lognormal random variables. The accuracy of these methods has been studied in previous works, under the assumption of having all summands signals (individual interference signals) identically distributed. Such assumption rarely holds in practical cases of emerging wireless systems, where interference may stem from far-away macrocells and nearby transmitters, causing the interference signals to have different moments. In this paper we present an analysis of Wilkinson's method and Schwartz and Yeh's method, for the general case when the summands have different mean values and standard deviations in decibel units. We show that Schwartz and Yeh's method provides better accuracy than Wilkinson's method and is virtually invariant with the difference of the mean values and standard deviations of the summands, and the number of summands.
{"title":"Statistics of the sum of lognormal variables in wireless communications","authors":"Paulo Cardieri, Theodore S. Rappaport","doi":"10.1109/VETECS.2000.851587","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851587","url":null,"abstract":"Schwartz and Yeh's method (1982) and Wilkinson's method are widely used to compute the moments of the total co-channel interference in wireless communication, usually modeled as the sum of lognormal random variables. The accuracy of these methods has been studied in previous works, under the assumption of having all summands signals (individual interference signals) identically distributed. Such assumption rarely holds in practical cases of emerging wireless systems, where interference may stem from far-away macrocells and nearby transmitters, causing the interference signals to have different moments. In this paper we present an analysis of Wilkinson's method and Schwartz and Yeh's method, for the general case when the summands have different mean values and standard deviations in decibel units. We show that Schwartz and Yeh's method provides better accuracy than Wilkinson's method and is virtually invariant with the difference of the mean values and standard deviations of the summands, and the number of summands.","PeriodicalId":318880,"journal":{"name":"VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026)","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130237845","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 : 2000-05-15DOI: 10.1109/VETECS.2000.851431
A. Yamaguchi, Y. Takeuchi, F. Watanabe, Toshikazu Yokai
We have developed a wideband code division multiple access (CDMA) testbed for the purpose of verifying an International Mobile Telecommunications-2000 (IMT-2000) system. The testbed has capabilities of soft handover (SHO) with an algorithm based on the received SIR. We report the performance of SHO from the results of laboratory/field experiments and computer simulations. An urban area and a suburban area were chosen for field experiments. This paper discusses the influence of SHO parameters and the propagation environment on the performance of SHO. Furthermore, we evaluated some SHO algorithms by computer simulations with propagation data measured in the field experiments of both areas.
{"title":"Soft handover performance of a wideband CDMA testbed system for IMT-2000","authors":"A. Yamaguchi, Y. Takeuchi, F. Watanabe, Toshikazu Yokai","doi":"10.1109/VETECS.2000.851431","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851431","url":null,"abstract":"We have developed a wideband code division multiple access (CDMA) testbed for the purpose of verifying an International Mobile Telecommunications-2000 (IMT-2000) system. The testbed has capabilities of soft handover (SHO) with an algorithm based on the received SIR. We report the performance of SHO from the results of laboratory/field experiments and computer simulations. An urban area and a suburban area were chosen for field experiments. This paper discusses the influence of SHO parameters and the propagation environment on the performance of SHO. Furthermore, we evaluated some SHO algorithms by computer simulations with propagation data measured in the field experiments of both areas.","PeriodicalId":318880,"journal":{"name":"VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130443987","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 : 2000-05-15DOI: 10.1109/VETECS.2000.851654
Jong Won Park, K. Kwak
The study on adaptive antenna array systems has been investigated to combat multiple access interference for CDMA systems. An adaptive antenna array can cancel out the undesired signal using beamforming. However if there are interfering signals from undesired users with the same arrival angle as that of a desired user an adaptive antenna array cannot suppress it. This paper proposes an adaptive antenna array including a multiuser detection unit to cancel out remaining interference at the same beamforming region (arrival angle). The performance analysis of the proposed system is developed for frequency selective Rayleigh fading channels. Simulation results show that the proposed system provides a significantly enhanced performance.
{"title":"Multiuser detection scheme using adaptive antenna array over Rayleigh fading channels","authors":"Jong Won Park, K. Kwak","doi":"10.1109/VETECS.2000.851654","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851654","url":null,"abstract":"The study on adaptive antenna array systems has been investigated to combat multiple access interference for CDMA systems. An adaptive antenna array can cancel out the undesired signal using beamforming. However if there are interfering signals from undesired users with the same arrival angle as that of a desired user an adaptive antenna array cannot suppress it. This paper proposes an adaptive antenna array including a multiuser detection unit to cancel out remaining interference at the same beamforming region (arrival angle). The performance analysis of the proposed system is developed for frequency selective Rayleigh fading channels. Simulation results show that the proposed system provides a significantly enhanced performance.","PeriodicalId":318880,"journal":{"name":"VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126713355","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 : 2000-05-15DOI: 10.1109/VETECS.2000.851545
M. F. Turiq, Andrew Nix, Derek Love’
This paper presents the design and performance of a pilot tone-aided 32 QAM modem developed for wireless ISDN applications. The modem is capable of transmitting a gross data rate of 70 kbit/s in a 20 kHz channel spacing. A low complexity receiver has been designed that allows the effects of fading and frequency offset to be removed digitally at a low IF using information extracted from the pilot tone. The design has been fully evaluated in narrowband Rayleigh and Rician fading channels. Computer simulations show that extreme Doppler shifts and frequency offsets have little effect on system performance. The design is suitable for mobile radio as well as fixed applications such as wireless in the local loop (WLL).
{"title":"Efficient implementation of pilot-aided 32 QAM for fixed wireless and mobile ISDN applications","authors":"M. F. Turiq, Andrew Nix, Derek Love’","doi":"10.1109/VETECS.2000.851545","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851545","url":null,"abstract":"This paper presents the design and performance of a pilot tone-aided 32 QAM modem developed for wireless ISDN applications. The modem is capable of transmitting a gross data rate of 70 kbit/s in a 20 kHz channel spacing. A low complexity receiver has been designed that allows the effects of fading and frequency offset to be removed digitally at a low IF using information extracted from the pilot tone. The design has been fully evaluated in narrowband Rayleigh and Rician fading channels. Computer simulations show that extreme Doppler shifts and frequency offsets have little effect on system performance. The design is suitable for mobile radio as well as fixed applications such as wireless in the local loop (WLL).","PeriodicalId":318880,"journal":{"name":"VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126776817","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 : 2000-05-15DOI: 10.1109/VETECS.2000.851279
A. Berthet, J. Fang, F. Buda, E. Lemois, P. Tortelier
In this paper, we consider iterative decoding of multidimensional product codes (MPC). Such codes, also called iterated codes, were first introduced by Elias (1954). After a formal definition of MPG, we compute their low-weight distribution. Using this distribution, we derive an improved asymptotic union bound on maximum likelihood (ML) decoding of such codes over a Gaussian channel. The main part of the paper is devoted to a comparison of efficient SISO algorithms, used as basic tools in the iterative decoding process. Simulation results show that MPC may be more suitable than any other schemes for packet wireless transmission involving packet sizes of less than 1000 information bits and requiring very low packet error rates (PER).
{"title":"A comparison of SISO algorithms for iterative decoding of multidimensional product codes","authors":"A. Berthet, J. Fang, F. Buda, E. Lemois, P. Tortelier","doi":"10.1109/VETECS.2000.851279","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851279","url":null,"abstract":"In this paper, we consider iterative decoding of multidimensional product codes (MPC). Such codes, also called iterated codes, were first introduced by Elias (1954). After a formal definition of MPG, we compute their low-weight distribution. Using this distribution, we derive an improved asymptotic union bound on maximum likelihood (ML) decoding of such codes over a Gaussian channel. The main part of the paper is devoted to a comparison of efficient SISO algorithms, used as basic tools in the iterative decoding process. Simulation results show that MPC may be more suitable than any other schemes for packet wireless transmission involving packet sizes of less than 1000 information bits and requiring very low packet error rates (PER).","PeriodicalId":318880,"journal":{"name":"VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123179806","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 : 2000-05-15DOI: 10.1109/VETECS.2000.851418
T. Hunziker, D. Dahlhaus
We consider a general, bandwidth efficient multicarrier transmission scheme without guard periods. Intersymbol and interchannel interferences are limited by using nonorthogonal pulses with good time-frequency localization characteristics, i.e., concentration of the energy in both time and frequency domains. This lets us derive a receiver of moderate complexity, employing iterative methods for the symbol detection. The achievable performance with the transmission and detection scheme is assessed by means of computer simulations and compared against the theoretical error rate of a corresponding interference-free transmission.
{"title":"Iterative symbol detection for bandwidth efficient nonorthogonal multicarrier transmission","authors":"T. Hunziker, D. Dahlhaus","doi":"10.1109/VETECS.2000.851418","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851418","url":null,"abstract":"We consider a general, bandwidth efficient multicarrier transmission scheme without guard periods. Intersymbol and interchannel interferences are limited by using nonorthogonal pulses with good time-frequency localization characteristics, i.e., concentration of the energy in both time and frequency domains. This lets us derive a receiver of moderate complexity, employing iterative methods for the symbol detection. The achievable performance with the transmission and detection scheme is assessed by means of computer simulations and compared against the theoretical error rate of a corresponding interference-free transmission.","PeriodicalId":318880,"journal":{"name":"VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026)","volume":"606 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123255345","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 : 2000-05-15DOI: 10.1109/VETECS.2000.851713
J. Koo, S. Ko, Hyung-Jin Choi
A three-stage channel estimation scheme is proposed for the down link of an asynchronous W-CDMA system in a frequency-selective Rayleigh-fading channel. At the first stage, zero-delay channel estimation can be obtained by using a decision-directed prediction filter in SIR measurement, therefore we can achieve fast power control. The second stage performs the data decision to make a virtual pilot channel for the next stage by using the weighted multi-slot averaging (WMSA) channel estimation scheme. Finally, the third stage performs the channel estimation of the "block-wise sliding average" type by using the virtual pilot channel obtained in the second stage. The performance of the proposed channel estimation scheme is compared with that of other schemes for various Doppler frequencies. By using Monte-Carlo computer simulations, we show that the proposed channel estimator is superior to other estimation schemes such as the WMSA (K=1) and DD-RAKE.
{"title":"Enhanced channel estimation for W-CDMA forward link using pilot symbols over Rayleigh-fading multipath channels","authors":"J. Koo, S. Ko, Hyung-Jin Choi","doi":"10.1109/VETECS.2000.851713","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851713","url":null,"abstract":"A three-stage channel estimation scheme is proposed for the down link of an asynchronous W-CDMA system in a frequency-selective Rayleigh-fading channel. At the first stage, zero-delay channel estimation can be obtained by using a decision-directed prediction filter in SIR measurement, therefore we can achieve fast power control. The second stage performs the data decision to make a virtual pilot channel for the next stage by using the weighted multi-slot averaging (WMSA) channel estimation scheme. Finally, the third stage performs the channel estimation of the \"block-wise sliding average\" type by using the virtual pilot channel obtained in the second stage. The performance of the proposed channel estimation scheme is compared with that of other schemes for various Doppler frequencies. By using Monte-Carlo computer simulations, we show that the proposed channel estimator is superior to other estimation schemes such as the WMSA (K=1) and DD-RAKE.","PeriodicalId":318880,"journal":{"name":"VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126438780","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 : 2000-05-15DOI: 10.1109/VETECS.2000.851484
Chi-Jui Ho, John A. Copeland, C. Lea, Gordon L. Stuber
We propose a mathematical model to analyze call admission control schemes for a DS/CDMA cellular network. Although similar models have been proposed, they suffer some problems. The proposed model of this paper intends to correct them. In addition, we combine a modified linear programming technique to explore the issue of finding a better call admission control scheme for a DS/CDMA cellular network.
{"title":"Impact of the cell size on the cell's Erlang capacity and call admission control in the DS/CDMA cellular networks","authors":"Chi-Jui Ho, John A. Copeland, C. Lea, Gordon L. Stuber","doi":"10.1109/VETECS.2000.851484","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851484","url":null,"abstract":"We propose a mathematical model to analyze call admission control schemes for a DS/CDMA cellular network. Although similar models have been proposed, they suffer some problems. The proposed model of this paper intends to correct them. In addition, we combine a modified linear programming technique to explore the issue of finding a better call admission control scheme for a DS/CDMA cellular network.","PeriodicalId":318880,"journal":{"name":"VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122185015","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 : 2000-05-15DOI: 10.1109/VETECS.2000.851417
Hyo-Joo Ahn, Yoan Shin, S. Im
We present a new block coding scheme for reduction of peak-to-average power ratio (PAPR) of an orthogonal frequency division multiplexing (OFDM) system. Since variation in signal amplitudes of an OFDM system is wide (i.e., large PAPR), performance of the system is significantly degraded by the nonlinearity of a high power amplifier (HPA) in the transmitter. In order to mitigate this distortion, we propose a block coding scheme which provides error correction capability, and also achieves the minimum PAPR for the OFDM system utilizing QPSK modulation and 4 subcarriers. Simulation results show that the proposed scheme significantly improves the bit error rate performance as compared to an uncoded system when an HPA is employed.
{"title":"A block coding scheme for peak-to-average power ratio reduction in an orthogonal frequency division multiplexing system","authors":"Hyo-Joo Ahn, Yoan Shin, S. Im","doi":"10.1109/VETECS.2000.851417","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851417","url":null,"abstract":"We present a new block coding scheme for reduction of peak-to-average power ratio (PAPR) of an orthogonal frequency division multiplexing (OFDM) system. Since variation in signal amplitudes of an OFDM system is wide (i.e., large PAPR), performance of the system is significantly degraded by the nonlinearity of a high power amplifier (HPA) in the transmitter. In order to mitigate this distortion, we propose a block coding scheme which provides error correction capability, and also achieves the minimum PAPR for the OFDM system utilizing QPSK modulation and 4 subcarriers. Simulation results show that the proposed scheme significantly improves the bit error rate performance as compared to an uncoded system when an HPA is employed.","PeriodicalId":318880,"journal":{"name":"VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114141415","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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