Pub Date : 1990-05-06DOI: 10.1109/VETEC.1990.110398
G. Falciasecca, M. Frullone, G. Riva, A. M. Serra
The effect of unpredictable traffic oscillations (due to traffic jams or accidents for example) occurring in urban areas with heavy road traffic and resulting in unacceptable performances of mobile radio systems are studied. The main goal is to determine whether an improvement in counteracting traffic bursts can be accomplished by means of dynamic channel allocation (DCA), with respect to fixed schemes. The control and management procedures used in the analysis do not represent a proposal for the architecture of the final system. They are very simple, and should be intended only as tools for illustrating the capabilities of DCA strategies. A description of a methodology suitable for evaluating system performances is given. The performance of fixed and dynamic schemes, with uniform spatial traffic distribution by means of a computer simulation program, are compared. A cellular layout based on a hexagonal grid where cell radius is equal to one kilometer is considered.<>
{"title":"On the impact of traffic burst on performances of high capacity cellular systems","authors":"G. Falciasecca, M. Frullone, G. Riva, A. M. Serra","doi":"10.1109/VETEC.1990.110398","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110398","url":null,"abstract":"The effect of unpredictable traffic oscillations (due to traffic jams or accidents for example) occurring in urban areas with heavy road traffic and resulting in unacceptable performances of mobile radio systems are studied. The main goal is to determine whether an improvement in counteracting traffic bursts can be accomplished by means of dynamic channel allocation (DCA), with respect to fixed schemes. The control and management procedures used in the analysis do not represent a proposal for the architecture of the final system. They are very simple, and should be intended only as tools for illustrating the capabilities of DCA strategies. A description of a methodology suitable for evaluating system performances is given. The performance of fixed and dynamic schemes, with uniform spatial traffic distribution by means of a computer simulation program, are compared. A cellular layout based on a hexagonal grid where cell radius is equal to one kilometer is considered.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128142098","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 : 1990-05-06DOI: 10.1109/VETEC.1990.110338
R. W. Nettleton
A novel family of techniques for assigning channels to calls in a cellular mobile telephone system based on real-time measurements of signal strength is introduced. A discussion of the behavior of the system using self-organizing techniques is presented. Results are presented for traffic distribution per channel, traffic distribution per cell site, mean time between handoffs, and mean signal-to-interference ratio. In each case, it is shown that the system behavior is progressive and degrades gracefully with increasing traffic; there is, for example, no threshold behavior in signal-to-interference ratio. This suggests that the concept can be introduced in stages as the traffic demand increases, without abrupt changes in system behavior.<>
{"title":"Traffic statistics in a self-organizing cellular telephone system","authors":"R. W. Nettleton","doi":"10.1109/VETEC.1990.110338","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110338","url":null,"abstract":"A novel family of techniques for assigning channels to calls in a cellular mobile telephone system based on real-time measurements of signal strength is introduced. A discussion of the behavior of the system using self-organizing techniques is presented. Results are presented for traffic distribution per channel, traffic distribution per cell site, mean time between handoffs, and mean signal-to-interference ratio. In each case, it is shown that the system behavior is progressive and degrades gracefully with increasing traffic; there is, for example, no threshold behavior in signal-to-interference ratio. This suggests that the concept can be introduced in stages as the traffic demand increases, without abrupt changes in system behavior.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128457857","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 : 1990-05-06DOI: 10.1109/VETEC.1990.110379
H. Zhou, S. Yoshida, T. Takeuchi
An antenna pattern diversity reception (APDR) system with a selection strategy based on the measurement of cross-channel-interference which has been confirmed to be a linear function of the multipath RMS delay spread, assuming BPSK as an example, is proposed. Theoretical analysis and computer simulation have been performed to study the effects of an APDR system with minimum RMS delay spread branch-selection strategy. It is confirmed that such a system is more effective in reducing the RMS delay spread, broadening the coherence bandwidth, and decreasing bit error ratio (BER) than a system with a conventional maximum signal strength branch-selection strategy in severe frequency-selective fading environments. A field experiment was carried out. Based on the measured data and computer simulation, the proposed system is shown to work well, even in a real urban area.<>
{"title":"Selection diversity reception based on cross-channel-interference measurement for digital mobile radio","authors":"H. Zhou, S. Yoshida, T. Takeuchi","doi":"10.1109/VETEC.1990.110379","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110379","url":null,"abstract":"An antenna pattern diversity reception (APDR) system with a selection strategy based on the measurement of cross-channel-interference which has been confirmed to be a linear function of the multipath RMS delay spread, assuming BPSK as an example, is proposed. Theoretical analysis and computer simulation have been performed to study the effects of an APDR system with minimum RMS delay spread branch-selection strategy. It is confirmed that such a system is more effective in reducing the RMS delay spread, broadening the coherence bandwidth, and decreasing bit error ratio (BER) than a system with a conventional maximum signal strength branch-selection strategy in severe frequency-selective fading environments. A field experiment was carried out. Based on the measured data and computer simulation, the proposed system is shown to work well, even in a real urban area.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132195829","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 : 1990-05-06DOI: 10.1109/VETEC.1990.110377
S. Ariyavisitakul
A low-complexity equalization technique for improving the reliability of portable radio links in the presence of multipath time delay spread is described. A technique that operates on hard-limited received signals, with only the phase information available, is presented. The use of passband hard-limiters in radio front end circuits reduces the complexity of portable radio receivers. An adaptive phase equalizer structure using decision-directed phase tracking which does not require the multiplication operations required in most conventional equalization algorithms is proposed. A receiver that includes a time-reversal structure and a joint estimator for optimum timing recovery and equalizer training is described. The time-reversal structure plays a crucial role in maximizing the compensation capability of the phase equalizer. The combined use of phase equalization and diversity reception is also considered. Computer simulations confirm the feasibility of the proposed receiver structure.<>
{"title":"Equalization of a hard-limited slowly-fading multipath signal using a phase equalizer with a time-reversal structure","authors":"S. Ariyavisitakul","doi":"10.1109/VETEC.1990.110377","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110377","url":null,"abstract":"A low-complexity equalization technique for improving the reliability of portable radio links in the presence of multipath time delay spread is described. A technique that operates on hard-limited received signals, with only the phase information available, is presented. The use of passband hard-limiters in radio front end circuits reduces the complexity of portable radio receivers. An adaptive phase equalizer structure using decision-directed phase tracking which does not require the multiplication operations required in most conventional equalization algorithms is proposed. A receiver that includes a time-reversal structure and a joint estimator for optimum timing recovery and equalizer training is described. The time-reversal structure plays a crucial role in maximizing the compensation capability of the phase equalizer. The combined use of phase equalization and diversity reception is also considered. Computer simulations confirm the feasibility of the proposed receiver structure.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":"247 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134486447","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 : 1990-05-06DOI: 10.1109/VETEC.1990.110400
K. J. Guth, T. Ha
Automatic repeat request (ARQ) techniques are often used by a packet-switching data communication network to provide an error-free communications link between stations. In an effort to improve the throughput on a short-range, RF, packet-switching data communications network, an adaptive ARQ strategy applied to stop-and-wait (SW) protocols was developed. To provide a system designer with flexibility, different adaptive strategies for different systems and link conditions were developed. Examples of information transfer between two stations using the adaptive SW protocol are presented. A simulation to compute the throughput efficiency of several adaptive SW protocols was performed. A comparison of the throughput efficiencies of the simulated adaptive SW protocol with the nonadaptive SW protocol showed good gains could be achieved using the adaptive strategy when the networks are subject to high channel bit error rates.<>
{"title":"An adaptive stop-and-wait ARQ strategy for mobile data communications","authors":"K. J. Guth, T. Ha","doi":"10.1109/VETEC.1990.110400","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110400","url":null,"abstract":"Automatic repeat request (ARQ) techniques are often used by a packet-switching data communication network to provide an error-free communications link between stations. In an effort to improve the throughput on a short-range, RF, packet-switching data communications network, an adaptive ARQ strategy applied to stop-and-wait (SW) protocols was developed. To provide a system designer with flexibility, different adaptive strategies for different systems and link conditions were developed. Examples of information transfer between two stations using the adaptive SW protocol are presented. A simulation to compute the throughput efficiency of several adaptive SW protocols was performed. A comparison of the throughput efficiencies of the simulated adaptive SW protocol with the nonadaptive SW protocol showed good gains could be achieved using the adaptive strategy when the networks are subject to high channel bit error rates.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133060302","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 : 1990-05-06DOI: 10.1109/VETEC.1990.110320
M.E. Margoudakis, T. Switzer
Northern Telecom has successfully demonstrated the operation of a time division multiple access (TDMA) demonstration system using six channels multiplexed onto a single RF carrier frequency and utilizing a nominal RF bandwidth of 30 kHz. This matches the analog FM bandwidth, and permits simple transition from existing RF channel assignments to digital channels. The architecture and operation of the digital cellular demonstration system are described. The demonstrations included two digital mobile units making simultaneous use of the system in either or both of two cells. Call set-up, hand-off, and disconnect were demonstrated by interfacing to the DMS-MTX, a standard configuration cellular switching system. Subscriber data transmission over the mobile radio channel at a rate of 9.6 kbit/s was also included as part of the demonstrations.<>
{"title":"Northern Telecom TDMA digital cellular demonstration system","authors":"M.E. Margoudakis, T. Switzer","doi":"10.1109/VETEC.1990.110320","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110320","url":null,"abstract":"Northern Telecom has successfully demonstrated the operation of a time division multiple access (TDMA) demonstration system using six channels multiplexed onto a single RF carrier frequency and utilizing a nominal RF bandwidth of 30 kHz. This matches the analog FM bandwidth, and permits simple transition from existing RF channel assignments to digital channels. The architecture and operation of the digital cellular demonstration system are described. The demonstrations included two digital mobile units making simultaneous use of the system in either or both of two cells. Call set-up, hand-off, and disconnect were demonstrated by interfacing to the DMS-MTX, a standard configuration cellular switching system. Subscriber data transmission over the mobile radio channel at a rate of 9.6 kbit/s was also included as part of the demonstrations.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132320222","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 : 1990-05-06DOI: 10.1109/VETEC.1990.110297
Y. Mori, H. Yabuki, M. Ohba, M. Sagawa, M. Makimoto, I. Shibazaki
Compact RF circuit modules using multilayered printed circuit boards (M-PCBs) are described. The theoretical analysis of split-ring resonators and spiral inductors, fundamental RF circuits elements embedded in M-PCBs, is presented. RF circuit modules, such as a frequency synthesizer, a phase-locked loop modulator, an up-converter, and a receiver front-end are demonstrated to be applicable to land mobile communication equipment. RF circuit modules using M-PCBs have a structure suitable for excellent antivibration characteristics, and the size of the newly developed modules has been reduced to one-quarter of that of conventional modules designed by surface-mount technology.<>
{"title":"Miniaturized RF-circuit modules for land mobile communication equipment","authors":"Y. Mori, H. Yabuki, M. Ohba, M. Sagawa, M. Makimoto, I. Shibazaki","doi":"10.1109/VETEC.1990.110297","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110297","url":null,"abstract":"Compact RF circuit modules using multilayered printed circuit boards (M-PCBs) are described. The theoretical analysis of split-ring resonators and spiral inductors, fundamental RF circuits elements embedded in M-PCBs, is presented. RF circuit modules, such as a frequency synthesizer, a phase-locked loop modulator, an up-converter, and a receiver front-end are demonstrated to be applicable to land mobile communication equipment. RF circuit modules using M-PCBs have a structure suitable for excellent antivibration characteristics, and the size of the newly developed modules has been reduced to one-quarter of that of conventional modules designed by surface-mount technology.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133957993","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 : 1990-05-06DOI: 10.1109/VETEC.1990.110387
A. Turkmani, A. de Toledo
A software investigation was undertaken to assess the performance of signal transmissions over a Rayleigh fading mobile radio channel, and to compare the effective utilization of the channel by other time diversity techniques. It involved the simulation of a communication system using Manchester-encoded data with a bit rate of 8 kb/s, phase shift keying (PSK) modulation, and ideal coherent demodulation. The diversity techniques investigated are voting, selection, and combining with different signal strength weighting factors. Results show that postdetection linear combining (unity weighting factor) yields the maximum diversity improvement. It is shown that an improvement in the bit error rate (BER) performance is possible without increasing the number of repeated words.<>
{"title":"Time diversity for digital mobile radio","authors":"A. Turkmani, A. de Toledo","doi":"10.1109/VETEC.1990.110387","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110387","url":null,"abstract":"A software investigation was undertaken to assess the performance of signal transmissions over a Rayleigh fading mobile radio channel, and to compare the effective utilization of the channel by other time diversity techniques. It involved the simulation of a communication system using Manchester-encoded data with a bit rate of 8 kb/s, phase shift keying (PSK) modulation, and ideal coherent demodulation. The diversity techniques investigated are voting, selection, and combining with different signal strength weighting factors. Results show that postdetection linear combining (unity weighting factor) yields the maximum diversity improvement. It is shown that an improvement in the bit error rate (BER) performance is possible without increasing the number of repeated words.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128485157","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 : 1990-05-06DOI: 10.1109/VETEC.1990.110375
L. Carter, T. Maclean
A novel expression for the attenuation of a radio wave propagating over a mixed land-sea path successfully predicts the recovery of field strength over the sea path. An initial series of measurements has been made in the Auckland area to determine whether the recovery effect is a significant factor at cellular radio frequencies. The results presented are limited by the fact that they were taken in a real environment, rather than in controlled laboratory conditions. It is therefore difficult to eliminate unwanted variables, particularly the effects of clutter. Nevertheless, the results do show consistently that signal enhancement occurs over a sea-water path at cellular radio frequencies.<>
{"title":"Recovery effect in cellular radio systems","authors":"L. Carter, T. Maclean","doi":"10.1109/VETEC.1990.110375","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110375","url":null,"abstract":"A novel expression for the attenuation of a radio wave propagating over a mixed land-sea path successfully predicts the recovery of field strength over the sea path. An initial series of measurements has been made in the Auckland area to determine whether the recovery effect is a significant factor at cellular radio frequencies. The results presented are limited by the fact that they were taken in a real environment, rather than in controlled laboratory conditions. It is therefore difficult to eliminate unwanted variables, particularly the effects of clutter. Nevertheless, the results do show consistently that signal enhancement occurs over a sea-water path at cellular radio frequencies.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":"1 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116828796","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 : 1990-05-06DOI: 10.1109/VETEC.1990.110368
G. Femenias, R. Agustí
The performance of 64 kbit/s two-branch switched-diversity 4DPSK (differential phase shift keying) and TCM-8DPSK systems in the presence of a simulated Rayleigh fading channel are analyzed. The bit error rate (BER) is obtained as a function of switching threshold, maximum Doppler shift frequency of the channel, and interleaving buffer size. The optimum switching threshold is determined as a function of the other parameters. It is found that the location of the optimum switching threshold is nearly constant for different interleaving buffer sizes, and practically unaffected by the Doppler frequency. Using the optimum threshold, the BER-performance of the systems is determined with Doppler frequency and interleaving buffer size as parameters. One of the most significant results is that the switched-diversity trellis-coded modulation (TCM) 8DPSK system improves the switched-diversity 4DPSK performance by more than 8 dB for a BER >
{"title":"Switched-diversity trellis-coded 8-DPSK for mobile radio applications","authors":"G. Femenias, R. Agustí","doi":"10.1109/VETEC.1990.110368","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110368","url":null,"abstract":"The performance of 64 kbit/s two-branch switched-diversity 4DPSK (differential phase shift keying) and TCM-8DPSK systems in the presence of a simulated Rayleigh fading channel are analyzed. The bit error rate (BER) is obtained as a function of switching threshold, maximum Doppler shift frequency of the channel, and interleaving buffer size. The optimum switching threshold is determined as a function of the other parameters. It is found that the location of the optimum switching threshold is nearly constant for different interleaving buffer sizes, and practically unaffected by the Doppler frequency. Using the optimum threshold, the BER-performance of the systems is determined with Doppler frequency and interleaving buffer size as parameters. One of the most significant results is that the switched-diversity trellis-coded modulation (TCM) 8DPSK system improves the switched-diversity 4DPSK performance by more than 8 dB for a BER <or=10/sup -3/, a Doppler frequency of 5 Hz, and an interleaving buffer size of 20*5000 symbols.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116951675","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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