Pub Date : 1997-09-01DOI: 10.1109/PIMRC.1997.624353
N. Nefedov
To speedup the simulations aimed at different error control and interleaving schemes evaluation there is a need for generative models of the radio layer communication link. A method of modelling discrete channels with hard and soft decision outputs is suggested. This method is based on nested hidden Markov model (HMM) and implemented as COSSAP library modules. The verification made by simulations of GSM speech traffic confirmed the validity of suggested approach.
{"title":"Generative Markov models for discrete channel modelling","authors":"N. Nefedov","doi":"10.1109/PIMRC.1997.624353","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.624353","url":null,"abstract":"To speedup the simulations aimed at different error control and interleaving schemes evaluation there is a need for generative models of the radio layer communication link. A method of modelling discrete channels with hard and soft decision outputs is suggested. This method is based on nested hidden Markov model (HMM) and implemented as COSSAP library modules. The verification made by simulations of GSM speech traffic confirmed the validity of suggested approach.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131199106","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 : 1997-09-01DOI: 10.1109/PIMRC.1997.624395
I. Furió, G. Femenias
This paper considers the application of I-Q trellis coded modulation (TCM) techniques to synchronous direct sequence code division multiple access (S-DS/CDMA) communication over frequency-selective fading mobile radio channels. The effect of the optimum adaptive coherent RAKE receiver structure with selection of the largest outputs is studied and an exact analytical expression for the pairwise error probability is obtained. This expression is used to evaluate the average BER upper bound through the transfer function bounding technique. The influence over the average BER of various system parameters like the number of active users, the number of selected outputs or sequence length are considered.
{"title":"I-QTCM QPSK synchronous DS/CDMA over frequency-selective multipath Rayleigh fading channels with selection diversity","authors":"I. Furió, G. Femenias","doi":"10.1109/PIMRC.1997.624395","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.624395","url":null,"abstract":"This paper considers the application of I-Q trellis coded modulation (TCM) techniques to synchronous direct sequence code division multiple access (S-DS/CDMA) communication over frequency-selective fading mobile radio channels. The effect of the optimum adaptive coherent RAKE receiver structure with selection of the largest outputs is studied and an exact analytical expression for the pairwise error probability is obtained. This expression is used to evaluate the average BER upper bound through the transfer function bounding technique. The influence over the average BER of various system parameters like the number of active users, the number of selected outputs or sequence length are considered.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"34 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132602011","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 : 1997-09-01DOI: 10.1109/PIMRC.1997.630920
S. Kwon, Tae-hyun Moon, Jae-Hyuck Lee, C. Kang
A blind equalization algorithm may be switched to a decision-directed (DD) scheme in order to speed up the convergence rate. In this paper, we propose a new blind equalization scheme that automatically switches to the DD mode. The proposed scheme operates in two modes: a blind equalization mode and a DD mode. The mode is determined by the region in which the equalizer output lies, and the region varies as function of the estimated value of the error variance. Only the equalized signal that falls in the region of confidence is used to calculate the variance. From simulation results, it is shown that this scheme can achieve faster convergence and small MSE.
{"title":"A blind equalization with the variable decision region","authors":"S. Kwon, Tae-hyun Moon, Jae-Hyuck Lee, C. Kang","doi":"10.1109/PIMRC.1997.630920","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.630920","url":null,"abstract":"A blind equalization algorithm may be switched to a decision-directed (DD) scheme in order to speed up the convergence rate. In this paper, we propose a new blind equalization scheme that automatically switches to the DD mode. The proposed scheme operates in two modes: a blind equalization mode and a DD mode. The mode is determined by the region in which the equalizer output lies, and the region varies as function of the estimated value of the error variance. Only the equalized signal that falls in the region of confidence is used to calculate the variance. From simulation results, it is shown that this scheme can achieve faster convergence and small MSE.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133417148","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 : 1997-09-01DOI: 10.1109/PIMRC.1997.627063
E. Ince, Y. Guo, S. Barton
This paper presents a new approach to reduced complexity detection of partial response continuous phase modulated signals over channels with severe intersymbol interference (ISI). The detector combines the overall channel response for the CPM modulator with that of a multipath channel to calculate the branch metrics of a breadth-first sequential detection algorithm known as the T-algorithm. To our knowledge the reported work is the first attempt to make use of such a technique for equalisation of quaternary partial response CPM signals transmitted over multipath channels. Simulation of the performance of the receiver in multipath channels is reported.
{"title":"T-algorithm detection of partial response continuous phase modulated signals over multipath channels","authors":"E. Ince, Y. Guo, S. Barton","doi":"10.1109/PIMRC.1997.627063","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.627063","url":null,"abstract":"This paper presents a new approach to reduced complexity detection of partial response continuous phase modulated signals over channels with severe intersymbol interference (ISI). The detector combines the overall channel response for the CPM modulator with that of a multipath channel to calculate the branch metrics of a breadth-first sequential detection algorithm known as the T-algorithm. To our knowledge the reported work is the first attempt to make use of such a technique for equalisation of quaternary partial response CPM signals transmitted over multipath channels. Simulation of the performance of the receiver in multipath channels is reported.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134167369","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 : 1997-09-01DOI: 10.1109/PIMRC.1997.631055
J. Wagen, E. Lachat, Jingming Li
Based on measurements in five urban environments in three different cities, the accuracy of a ray tracing based model is characterized. First, the conventional characterization using the mean and standard deviation of the prediction error is used. Then, a figure of merit defined as the percentage of correct prediction with respect to a coverage threshold is computed. Finally, an example is given to illustrate how prediction results could be displayed to provide some insights into the accuracy of the model. For comparison purpose, results from power law curve fits are also analyzed. It is concluded that the standard deviation is a fair characterization of the accuracy of a model as long as its value is small (<-7 dB). For larger value, the figure of merit can be more useful. However, further work is needed to find reliable characteristics which could provide almost as much information as the visual inspection of the prediction results overlaid on the measurements.
{"title":"Performance evaluation of a ray tracing based microcellular coverage prediction tool","authors":"J. Wagen, E. Lachat, Jingming Li","doi":"10.1109/PIMRC.1997.631055","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.631055","url":null,"abstract":"Based on measurements in five urban environments in three different cities, the accuracy of a ray tracing based model is characterized. First, the conventional characterization using the mean and standard deviation of the prediction error is used. Then, a figure of merit defined as the percentage of correct prediction with respect to a coverage threshold is computed. Finally, an example is given to illustrate how prediction results could be displayed to provide some insights into the accuracy of the model. For comparison purpose, results from power law curve fits are also analyzed. It is concluded that the standard deviation is a fair characterization of the accuracy of a model as long as its value is small (<-7 dB). For larger value, the figure of merit can be more useful. However, further work is needed to find reliable characteristics which could provide almost as much information as the visual inspection of the prediction results overlaid on the measurements.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130344102","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 : 1997-09-01DOI: 10.1109/PIMRC.1997.630967
R. Verdone
Packet radio systems with random multiple access where the geometry of the scenario determines the presence of a maximum of two simultaneous transmitters, are analysed. Packet capture probability is evaluated in order to investigate the possible improvements of the random transmission power strategy first proposed by Lee (1987). Propagation is characterised by a path-loss exponent. The capture effect is taken into account by means of a threshold model. Averaging over interfering distance is accomplished. After an analytical development, the packet capture probability is found to be determinable by means of closed-form expressions. It is shown that the random transmission power strategy improves system performance in certain conditions. Some examples of application of this technique are given.
{"title":"On the performance improvement of packet radio systems with one single interferer due to random transmission power strategy","authors":"R. Verdone","doi":"10.1109/PIMRC.1997.630967","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.630967","url":null,"abstract":"Packet radio systems with random multiple access where the geometry of the scenario determines the presence of a maximum of two simultaneous transmitters, are analysed. Packet capture probability is evaluated in order to investigate the possible improvements of the random transmission power strategy first proposed by Lee (1987). Propagation is characterised by a path-loss exponent. The capture effect is taken into account by means of a threshold model. Averaging over interfering distance is accomplished. After an analytical development, the packet capture probability is found to be determinable by means of closed-form expressions. It is shown that the random transmission power strategy improves system performance in certain conditions. Some examples of application of this technique are given.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116672505","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 : 1997-09-01DOI: 10.1109/PIMRC.1997.631059
P. Hafezi, D. Wedge, M. Beach, M. Lawton
This paper presents the results of an investigation into the wideband propagation characteristics of four different indoor operational environments within the 5.2 GHz band using a swept time-delay cross-correlator (STDCC) channel sounder. For each environment the cumulative distribution of delay spread for both omni-directional and a 20 dB horn antenna are presented. It is shown that a suitably aligned narrowbeam antenna makes possible to achieve delay spread reduction through spatial filtering. The effects of moving people and different room transmission situations are also presented.
{"title":"Propagation measurements at 5.2 GHz in commercial and domestic environments","authors":"P. Hafezi, D. Wedge, M. Beach, M. Lawton","doi":"10.1109/PIMRC.1997.631059","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.631059","url":null,"abstract":"This paper presents the results of an investigation into the wideband propagation characteristics of four different indoor operational environments within the 5.2 GHz band using a swept time-delay cross-correlator (STDCC) channel sounder. For each environment the cumulative distribution of delay spread for both omni-directional and a 20 dB horn antenna are presented. It is shown that a suitably aligned narrowbeam antenna makes possible to achieve delay spread reduction through spatial filtering. The effects of moving people and different room transmission situations are also presented.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117304915","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 : 1997-09-01DOI: 10.1109/PIMRC.1997.627052
M. Lamarca, G. Vázquez
A blind algorithm for channel distortion compensation is presented which can be employed in spatial or temporal diversity receivers. The proposed technique can be used in frequency selective and frequency flat fading mobile channels, using burst transmission schemes in the first case and OFDM modulation in the second one. The algorithm is base on a deterministic criteria and is suited for estimation when short sets of data are available.
{"title":"Diversity techniques for blind channel equalization in mobile communications","authors":"M. Lamarca, G. Vázquez","doi":"10.1109/PIMRC.1997.627052","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.627052","url":null,"abstract":"A blind algorithm for channel distortion compensation is presented which can be employed in spatial or temporal diversity receivers. The proposed technique can be used in frequency selective and frequency flat fading mobile channels, using burst transmission schemes in the first case and OFDM modulation in the second one. The algorithm is base on a deterministic criteria and is suited for estimation when short sets of data are available.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124934547","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 : 1997-09-01DOI: 10.1109/PIMRC.1997.626994
J. Wen, Kuo-Gen Hsu, Ethan Chen, J. Wen
Power assignment schemes are man-made method used to enhance the capture effect of contention-based multiple access systems while Rayleigh fading, near/far effect and shadow fading are natural factors that cause the capture effect in radio communications. The combined impact of natural and man-made capture effects on the performance of a cellular system with finite population is studied. A Markov model is used to carry out an analysis of the system throughput and delay. Some numerical calculations are used to demonstrate the degree of performance improvement.
{"title":"Performance evaluation of random power assignment scheme on cellular mobile communications with finite population","authors":"J. Wen, Kuo-Gen Hsu, Ethan Chen, J. Wen","doi":"10.1109/PIMRC.1997.626994","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.626994","url":null,"abstract":"Power assignment schemes are man-made method used to enhance the capture effect of contention-based multiple access systems while Rayleigh fading, near/far effect and shadow fading are natural factors that cause the capture effect in radio communications. The combined impact of natural and man-made capture effects on the performance of a cellular system with finite population is studied. A Markov model is used to carry out an analysis of the system throughput and delay. Some numerical calculations are used to demonstrate the degree of performance improvement.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122986276","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 : 1997-09-01DOI: 10.1109/PIMRC.1997.627029
D. Wisely, I. Neild
This paper describes the design, construction and testing of a demonstration 100 Mbit/s tracked optical wireless telepoint system. The prototype uses switched linear laser and detector arrays, each imaged onto a small part of the total area, to allow wide coverage at high data rates. A separate tracking system monitors the relative mobility of nodes and switches the transceiver elements to maintain communication. A combination of operation at 1500 nm and a large number of switched laser elements (16) result in Class 1, eye safe, operation.
{"title":"A 100 Mbit/s tracked optical wireless telepoint","authors":"D. Wisely, I. Neild","doi":"10.1109/PIMRC.1997.627029","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.627029","url":null,"abstract":"This paper describes the design, construction and testing of a demonstration 100 Mbit/s tracked optical wireless telepoint system. The prototype uses switched linear laser and detector arrays, each imaged onto a small part of the total area, to allow wide coverage at high data rates. A separate tracking system monitors the relative mobility of nodes and switches the transceiver elements to maintain communication. A combination of operation at 1500 nm and a large number of switched laser elements (16) result in Class 1, eye safe, operation.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122006845","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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