Pub Date : 2000-05-15DOI: 10.1109/VETECS.2000.851631
C. Wong, B. Yeap, L. Hanzo
The performance of adaptive modulation-applied in conjunction with turbo equalization (TE)-is characterized in a noise limited environment over a slowly varying wideband multi-path Rayleigh fading channel. The iterative structure of the turbo equalizer was also exploited in order to invoke an iterative least mean square (LMS) channel estimator. Finally, the throughput performance of the adaptive modulation scheme was compared to that of its constituent modulation modes, where a gain of 1.5 dB to 1.7 dB was recorded.
{"title":"Wideband burst-by-burst adaptive modulation with turbo equalization and iterative channel estimation","authors":"C. Wong, B. Yeap, L. Hanzo","doi":"10.1109/VETECS.2000.851631","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851631","url":null,"abstract":"The performance of adaptive modulation-applied in conjunction with turbo equalization (TE)-is characterized in a noise limited environment over a slowly varying wideband multi-path Rayleigh fading channel. The iterative structure of the turbo equalizer was also exploited in order to invoke an iterative least mean square (LMS) channel estimator. Finally, the throughput performance of the adaptive modulation scheme was compared to that of its constituent modulation modes, where a gain of 1.5 dB to 1.7 dB was recorded.","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":"122409367","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.2000.851522
M. Hernandez, G. Janssen, R. Prasad
Multipath fading and multiple access interference (MAI) are the major constraints on the performance of DS/CDMA systems. Antenna arrays and multiuser detectors have been considered to increase the system capacity through mitigation of such impairments. Multiuser detectors have the capability of eliminating MAI, the near-far problem and providing a significant capacity increase. In order to gain from the enhancements of both: multi-user detection and adaptive antenna, we propose in this paper to combine both schemes for an asynchronous WCDMA system. The performance of the combined scheme is evaluated for the uplink over the Gaussian channel and the UMTS frequency selective Rayleigh fading channel. We make a comparison of the most promising multiuser structures and the recursive least square algorithm to control the beamformer.
{"title":"Uplink performance enhancement for WCDMA systems through adaptive antenna and multiuser detection","authors":"M. Hernandez, G. Janssen, R. Prasad","doi":"10.1109/VETECS.2000.851522","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851522","url":null,"abstract":"Multipath fading and multiple access interference (MAI) are the major constraints on the performance of DS/CDMA systems. Antenna arrays and multiuser detectors have been considered to increase the system capacity through mitigation of such impairments. Multiuser detectors have the capability of eliminating MAI, the near-far problem and providing a significant capacity increase. In order to gain from the enhancements of both: multi-user detection and adaptive antenna, we propose in this paper to combine both schemes for an asynchronous WCDMA system. The performance of the combined scheme is evaluated for the uplink over the Gaussian channel and the UMTS frequency selective Rayleigh fading channel. We make a comparison of the most promising multiuser structures and the recursive least square algorithm to control the beamformer.","PeriodicalId":318880,"journal":{"name":"VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026)","volume":"26 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":"122428522","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.2000.851598
J. Mannerkoski, V. Koivunen
The performance of one blind channel identification algorithm and three blind equalizers is studied. The main concern is in investigating their behavior when the communication channel has little energy in the beginning of its response. In our previous experiments, the equalizers' performance has not been satisfactory for such channels. All considered equalizers are based on a pseudo-inversion of a block-Toeplitz matrix. We study the effect of the channel precursor magnitude on the singular values of the matrix and consequently on the equalizer performance. For each algorithm, scatter plots are used to evaluate the success of the equalization under various conditions. We provide an explanation to the success or failure of the equalizers, based on the magnitude of the singular values.
{"title":"Sensitivity of SIMO blind equalizers to the channel precursor magnitude","authors":"J. Mannerkoski, V. Koivunen","doi":"10.1109/VETECS.2000.851598","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851598","url":null,"abstract":"The performance of one blind channel identification algorithm and three blind equalizers is studied. The main concern is in investigating their behavior when the communication channel has little energy in the beginning of its response. In our previous experiments, the equalizers' performance has not been satisfactory for such channels. All considered equalizers are based on a pseudo-inversion of a block-Toeplitz matrix. We study the effect of the channel precursor magnitude on the singular values of the matrix and consequently on the equalizer performance. For each algorithm, scatter plots are used to evaluate the success of the equalization under various conditions. We provide an explanation to the success or failure of the equalizers, based on the magnitude of the singular values.","PeriodicalId":318880,"journal":{"name":"VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026)","volume":"45 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":"122704838","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.2000.851497
M. Airy, K. Rohani
Motivated by higher bandwidths and the need to handle a range of packet data services, several enhancements over the IS 95A/B packet interface have been proposed for third generation (3G) CDMA systems: enhanced physical layer to provide data rates greater than 64 kbps, enhanced MAC layer to support concurrent operation of any combination of voice, circuit and packet data, each with varying QoS and enhanced signaling to enable efficient resource management. The objective of this paper is to introduce concepts from queueing theory that address radio resource management issues for supporting packet data services over 3G CDMA systems.
{"title":"QoS and fairness for CDMA packet data","authors":"M. Airy, K. Rohani","doi":"10.1109/VETECS.2000.851497","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851497","url":null,"abstract":"Motivated by higher bandwidths and the need to handle a range of packet data services, several enhancements over the IS 95A/B packet interface have been proposed for third generation (3G) CDMA systems: enhanced physical layer to provide data rates greater than 64 kbps, enhanced MAC layer to support concurrent operation of any combination of voice, circuit and packet data, each with varying QoS and enhanced signaling to enable efficient resource management. The objective of this paper is to introduce concepts from queueing theory that address radio resource management issues for supporting packet data services over 3G CDMA systems.","PeriodicalId":318880,"journal":{"name":"VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026)","volume":"3 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":"114265891","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.2000.851640
K. K. Leung, L.-C. Wang
In this paper, we prove that the problem of maximizing data throughput by adaptive modulation and power control while meeting packet error requirements is NP-complete. A heuristic algorithm for integrated link adaptation and power control is thus proposed to achieve specified error rates and to improve overall throughput for real-time applications in wireless IP networks. The algorithm divides terminals into groups according to their signal path gains, and periodically adapts transmissions based on the required error rates, actual error statistics and average transmission power of each terminal group. Transmission power is adjusted by an enhanced Kalman-filter method to ensure successful reception. Simulation results reveal that the algorithm consistently delivers the specified error performance, and attempts to maximize network throughput for a wide range of parameter settings.
{"title":"Integrated link adaptation and power control for wireless IP networks","authors":"K. K. Leung, L.-C. Wang","doi":"10.1109/VETECS.2000.851640","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851640","url":null,"abstract":"In this paper, we prove that the problem of maximizing data throughput by adaptive modulation and power control while meeting packet error requirements is NP-complete. A heuristic algorithm for integrated link adaptation and power control is thus proposed to achieve specified error rates and to improve overall throughput for real-time applications in wireless IP networks. The algorithm divides terminals into groups according to their signal path gains, and periodically adapts transmissions based on the required error rates, actual error statistics and average transmission power of each terminal group. Transmission power is adjusted by an enhanced Kalman-filter method to ensure successful reception. Simulation results reveal that the algorithm consistently delivers the specified error performance, and attempts to maximize network throughput for a wide range of parameter settings.","PeriodicalId":318880,"journal":{"name":"VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026)","volume":"136 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":"122131251","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.2000.851622
M. Patzold, F. Laue
All Rayleigh fading channel simulators based on finite sums of weighted harmonic functions with determined frequencies and phases are constitutionally deterministic. We analyze the performance of this important class of fading channel simulators with respect to the bit error probability (BEP) of QPSK and DPSK systems. New exact and approximate formulas for the BEP are derived. Several analytical and simulation results for the BEP are presented by using a typical stochastic procedure (Monte Carlo method) and a typical deterministic procedure (method of exact Doppler spread) for the computation of the parameters of deterministic Rayleigh fading channel simulators.
{"title":"The performance of deterministic Rayleigh fading channel simulators with respect to the bit error probability","authors":"M. Patzold, F. Laue","doi":"10.1109/VETECS.2000.851622","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851622","url":null,"abstract":"All Rayleigh fading channel simulators based on finite sums of weighted harmonic functions with determined frequencies and phases are constitutionally deterministic. We analyze the performance of this important class of fading channel simulators with respect to the bit error probability (BEP) of QPSK and DPSK systems. New exact and approximate formulas for the BEP are derived. Several analytical and simulation results for the BEP are presented by using a typical stochastic procedure (Monte Carlo method) and a typical deterministic procedure (method of exact Doppler spread) for the computation of the parameters of deterministic Rayleigh fading channel simulators.","PeriodicalId":318880,"journal":{"name":"VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026)","volume":"38 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":"117004110","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.2000.851551
M. Dohler, M. Dell'Anna, A. Aghvami
The main objective of this work is to provide the probability transformation for the parameters describing an impinging wave from the outdoor to the indoor environment. An approximated deterministic outdoor-indoor model already developed is utilised to extract the probability density function (PDF) transformation rule for the delay, azimuth and elevation spectra. Since the interface model is applicable for frequencies of 2.4 GHz, 5.2 GHz and 60 GHz, the transformation holds for these frequencies.
{"title":"PDF-transformation for the outdoor-indoor propagation model","authors":"M. Dohler, M. Dell'Anna, A. Aghvami","doi":"10.1109/VETECS.2000.851551","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851551","url":null,"abstract":"The main objective of this work is to provide the probability transformation for the parameters describing an impinging wave from the outdoor to the indoor environment. An approximated deterministic outdoor-indoor model already developed is utilised to extract the probability density function (PDF) transformation rule for the delay, azimuth and elevation spectra. Since the interface model is applicable for frequencies of 2.4 GHz, 5.2 GHz and 60 GHz, the transformation holds for these frequencies.","PeriodicalId":318880,"journal":{"name":"VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026)","volume":"40 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":"128453646","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.2000.851509
J. M. Leitão, A. A. D. Sousa, Fernando Nunes Ferreira
This paper presents some of the developments we made with the goal of allowing a friendly control and simulation of a large number of autonomous agents based in behavior in interactive real-time systems. Our work has been specially oriented to the simulation and control of autonomous vehicles and pedestrians in the preparation of scenarios to driving simulation experiments in the DriS simulator. Because every element is intrinsically autonomous, only a few of them are usually addressed to implement the desired study event. Also, because our model is autonomous and controllable, we can use the same model in the implementation of both environment traffic and controlled vehicles. Our scripting language is based in Grafcet, a well known graphical language used in the specification and programming of industrial controllers. Our technique allows the imposition of both short time orders and long time goals to each autonomous element. Orders can be triggered reactively using sensors that monitor the state of virtual traffic and configurable timers that generate all the necessary fixed and variable time events.
{"title":"Graphical control of autonomous, virtual vehicles","authors":"J. M. Leitão, A. A. D. Sousa, Fernando Nunes Ferreira","doi":"10.1109/VETECS.2000.851509","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851509","url":null,"abstract":"This paper presents some of the developments we made with the goal of allowing a friendly control and simulation of a large number of autonomous agents based in behavior in interactive real-time systems. Our work has been specially oriented to the simulation and control of autonomous vehicles and pedestrians in the preparation of scenarios to driving simulation experiments in the DriS simulator. Because every element is intrinsically autonomous, only a few of them are usually addressed to implement the desired study event. Also, because our model is autonomous and controllable, we can use the same model in the implementation of both environment traffic and controlled vehicles. Our scripting language is based in Grafcet, a well known graphical language used in the specification and programming of industrial controllers. Our technique allows the imposition of both short time orders and long time goals to each autonomous element. Orders can be triggered reactively using sensors that monitor the state of virtual traffic and configurable timers that generate all the necessary fixed and variable time events.","PeriodicalId":318880,"journal":{"name":"VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026)","volume":"24 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":"128648033","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.2000.851213
B. Lindmark, M. Ahlberg, M. Nilsson, C. Beckman
Most of the current and future mobile communications systems are frequency duplex systems, i.e. the up- and down-link are separated in frequency. Since the effect of the radio channel is not constant with frequency, this potentially limits the capacity gain using adaptive antennas. We use 150 MHz measurement data to simulate adaptive beamforming in a suburban environment. The information from the up-link at 1741 MHz is used for beamforming at this frequency as well as on the down-link at 1839 MHz. Our results show a reduction in C/I improvement of up to 10 dB between the up- and down-link.
{"title":"Performance analysis of applying up-link estimates in the down-link beamforming using a dual polarized array","authors":"B. Lindmark, M. Ahlberg, M. Nilsson, C. Beckman","doi":"10.1109/VETECS.2000.851213","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851213","url":null,"abstract":"Most of the current and future mobile communications systems are frequency duplex systems, i.e. the up- and down-link are separated in frequency. Since the effect of the radio channel is not constant with frequency, this potentially limits the capacity gain using adaptive antennas. We use 150 MHz measurement data to simulate adaptive beamforming in a suburban environment. The information from the up-link at 1741 MHz is used for beamforming at this frequency as well as on the down-link at 1839 MHz. Our results show a reduction in C/I improvement of up to 10 dB between the up- and down-link.","PeriodicalId":318880,"journal":{"name":"VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026)","volume":"21 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":"124637190","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.2000.851246
L. Yang, L. Hanzo
The performance of Reed-Solomon (RS) codes is investigated over frequency-selective Rayleigh fading channels using M-ary orthogonal signaling schemes. 'Errors-and-erasures' decoding (E/sup 2/D) is considered, where erasures are judged based on Viterbi's (1982) ratio threshold test (RTT) and on the basis of the output likelihood ratio threshold test (LRT/sup 2/). The LRT/sup 2/ technique is compared with Viterbi's RTT, and both of these are compared to receivers using 'error-correction only' decoding (ECOD) over frequency-selective Rayleigh-fading channels, numerical results show that upon using E/sup 2/D, RS codes of a given code rate can achieve higher coding gain, than that without erasure information, and that the LRT/sup 2/ technique outperforms the RTT, provided that both schemes are operated at the optimum decision thresholds.
{"title":"Performance of errors-and-erasures decoded Reed-Solomon codes over frequency-selective Rayleigh fading channels using M-ary orthogonal signaling","authors":"L. Yang, L. Hanzo","doi":"10.1109/VETECS.2000.851246","DOIUrl":"https://doi.org/10.1109/VETECS.2000.851246","url":null,"abstract":"The performance of Reed-Solomon (RS) codes is investigated over frequency-selective Rayleigh fading channels using M-ary orthogonal signaling schemes. 'Errors-and-erasures' decoding (E/sup 2/D) is considered, where erasures are judged based on Viterbi's (1982) ratio threshold test (RTT) and on the basis of the output likelihood ratio threshold test (LRT/sup 2/). The LRT/sup 2/ technique is compared with Viterbi's RTT, and both of these are compared to receivers using 'error-correction only' decoding (ECOD) over frequency-selective Rayleigh-fading channels, numerical results show that upon using E/sup 2/D, RS codes of a given code rate can achieve higher coding gain, than that without erasure information, and that the LRT/sup 2/ technique outperforms the RTT, provided that both schemes are operated at the optimum decision thresholds.","PeriodicalId":318880,"journal":{"name":"VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026)","volume":"131 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":"126881854","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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