Pub Date : 1990-05-06DOI: 10.1109/VETEC.1990.110350
Lung-Sing Liang, Jin-Fu Chang
Contention-based time-division multiple access (TDMA) protocols have good performance in applications such as a very small aperture terminals, with medium to heavy traffic when the channel is error free. For the protocol to operate in a channel that may contain errors, a modified protocol is proposed. Results derived include the average frame length, the average number of waste slots, the average number of residual packets, and the average delay. Numerical examples shown include the effect of channel errors and the margin regained by proper error-control codes. The validity of these results has not only been verified by computer simulations, but also supported by intuitively reasonable trends demonstrated in numerical calculations.<>
{"title":"The effect of channel errors on a contention-based reservation TDMA protocol","authors":"Lung-Sing Liang, Jin-Fu Chang","doi":"10.1109/VETEC.1990.110350","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110350","url":null,"abstract":"Contention-based time-division multiple access (TDMA) protocols have good performance in applications such as a very small aperture terminals, with medium to heavy traffic when the channel is error free. For the protocol to operate in a channel that may contain errors, a modified protocol is proposed. Results derived include the average frame length, the average number of waste slots, the average number of residual packets, and the average delay. Numerical examples shown include the effect of channel errors and the margin regained by proper error-control codes. The validity of these results has not only been verified by computer simulations, but also supported by intuitively reasonable trends demonstrated in numerical calculations.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":"50 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":"128760861","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.1990.110374
H. Li, J. Cavers
It is demonstrated that adaptivity in pilot filter bandwidth can produce a significant improvement in the bit error ratio (BER) of a pilot aided calibration system. The utility of adjusting the filter bandwidths as vehicle speed changes is addressed. Since the optimum bandwidth varies with vehicle speed, some form of adaptivity is desirable. The adaptation technique is novel; the receiver selects the optimum member from a precalculated bank of stored filters, thereby reducing the search to one dimension. The technique can provide a 1.0 dB improvement for a normalized Doppler frequency of 2%; up to 2.0 dB can be gained when operating at a lower Doppler frequency. The algorithm is found to be very robust, in the sense that self-noise and decision feedback have little effect on its operation and the resulting BER.<>
{"title":"An adaptive filtering technique for pilot aided transmission systems","authors":"H. Li, J. Cavers","doi":"10.1109/VETEC.1990.110374","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110374","url":null,"abstract":"It is demonstrated that adaptivity in pilot filter bandwidth can produce a significant improvement in the bit error ratio (BER) of a pilot aided calibration system. The utility of adjusting the filter bandwidths as vehicle speed changes is addressed. Since the optimum bandwidth varies with vehicle speed, some form of adaptivity is desirable. The adaptation technique is novel; the receiver selects the optimum member from a precalculated bank of stored filters, thereby reducing the search to one dimension. The technique can provide a 1.0 dB improvement for a normalized Doppler frequency of 2%; up to 2.0 dB can be gained when operating at a lower Doppler frequency. The algorithm is found to be very robust, in the sense that self-noise and decision feedback have little effect on its operation and the resulting BER.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":"15 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":"131165533","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.1990.110346
S. Kallel, C. Leung
The preference improvement resulting from modifications to the original ARQ scheme proposed by E.J. Weldon (1982) for use in systems with finite-receiver buffers was analyzed in a previous paper. A modification involving the use of parity retransmission is studied. One drawback of using forward error correcting (FEC) codes is that the parity bits result in a degradation in efficiency under good channel conditions: the maximum throughput is limited to the FEC code rate. Two type II ARQ schemes which overcome this problem are studied. Lower bounds on the throughputs of the two schemes are obtained. The throughput of the type II ARQ scheme is no longer limited by one-half the rate of the FEC code used. Under good channel conditions, the throughput with the type II ARQ scheme is equivalent to not using FEC; as the channel degrades, it approaches the throughput with a rate one-half FEC code.<>
{"title":"Type II ARQ schemes with multiple copy decoding for mobile communications","authors":"S. Kallel, C. Leung","doi":"10.1109/VETEC.1990.110346","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110346","url":null,"abstract":"The preference improvement resulting from modifications to the original ARQ scheme proposed by E.J. Weldon (1982) for use in systems with finite-receiver buffers was analyzed in a previous paper. A modification involving the use of parity retransmission is studied. One drawback of using forward error correcting (FEC) codes is that the parity bits result in a degradation in efficiency under good channel conditions: the maximum throughput is limited to the FEC code rate. Two type II ARQ schemes which overcome this problem are studied. Lower bounds on the throughputs of the two schemes are obtained. The throughput of the type II ARQ scheme is no longer limited by one-half the rate of the FEC code used. Under good channel conditions, the throughput with the type II ARQ scheme is equivalent to not using FEC; as the channel degrades, it approaches the throughput with a rate one-half FEC code.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":" 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113948141","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.1990.110416
A. Mautschke, E. Furman, R. Decker
Data radio transmission as applied to the railroad environment is studied. It is shown that data transmission in a railway environment can be improved by utilizing a relatively modest forward error correction (FEC) technique. Analytical methods can be utilized to calculate an approximate carrier-to-noise ratio for data radio transmission without FEC. To determine the carrier-to-noise ratio with FEC, it is necessary to take measurements of the mean signal level versus the block success rate. It is shown that when an effective ratio coverage prediction model is utilized properly, good correlation exists between measured and predicted radio coverage. Furthermore, it is demonstrated that proper utilization of an FEC scheme has the effect of significantly improving radio coverage. At the 90% reliability level excellent agreement between measured and predicted results exists.<>
{"title":"Mobile data transmission in a railroad environment","authors":"A. Mautschke, E. Furman, R. Decker","doi":"10.1109/VETEC.1990.110416","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110416","url":null,"abstract":"Data radio transmission as applied to the railroad environment is studied. It is shown that data transmission in a railway environment can be improved by utilizing a relatively modest forward error correction (FEC) technique. Analytical methods can be utilized to calculate an approximate carrier-to-noise ratio for data radio transmission without FEC. To determine the carrier-to-noise ratio with FEC, it is necessary to take measurements of the mean signal level versus the block success rate. It is shown that when an effective ratio coverage prediction model is utilized properly, good correlation exists between measured and predicted radio coverage. Furthermore, it is demonstrated that proper utilization of an FEC scheme has the effect of significantly improving radio coverage. At the 90% reliability level excellent agreement between measured and predicted results exists.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":"1 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":"115998350","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.1990.110342
D. Lin, V. Varma, J. Dixon
A 16 kb/s speech-coding algorithm is described. Ways of mitigating the effects of transmission errors due to slow-fading channels are discussed. The coder yields near toll-quality speech with moderate delay and complexity. It is assumed that the portable radio link uses an error detection code. For mitigation of error effects in the received speech, through objective analysis and subjective evaluation, the critical speech parameters whose error could result in very undesirable speech degradation are identified. Then a method for altering these critical parameters when errors are detected in them is considered. Experiments were run with this method using several conceivable error detection arrangements for the radio link. Results show that it eliminates the loud and annoying pops and pings arising from errors in the critical parameters, and replaces them with subjectively more preferable silence or low-level buzzes.<>
{"title":"Design of a medium rate linear-predictive speech coder for digital portable radio communications","authors":"D. Lin, V. Varma, J. Dixon","doi":"10.1109/VETEC.1990.110342","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110342","url":null,"abstract":"A 16 kb/s speech-coding algorithm is described. Ways of mitigating the effects of transmission errors due to slow-fading channels are discussed. The coder yields near toll-quality speech with moderate delay and complexity. It is assumed that the portable radio link uses an error detection code. For mitigation of error effects in the received speech, through objective analysis and subjective evaluation, the critical speech parameters whose error could result in very undesirable speech degradation are identified. Then a method for altering these critical parameters when errors are detected in them is considered. Experiments were run with this method using several conceivable error detection arrangements for the radio link. Results show that it eliminates the loud and annoying pops and pings arising from errors in the critical parameters, and replaces them with subjectively more preferable silence or low-level buzzes.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":"46 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":"121049192","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.1990.110359
J. Horikoshi
A modulation scheme named pi /2-TFSK shows a superior error performance to MSK (minimum shift keying) in a frequency-selective mobile radio channel. The 2-bit differential detection of pi /2-TFSK with a raised-cosine type premodulation lowpass filter is analyzed under the frequency-selective mobile radio environment, and a better error performance than MSK is demonstrated. These characteristics are confirmed through an experimental simulation in the laboratory. As the frequency-selective fading model a two Rayleigh-fading-wave model with a constant group time delay is adopted. The system is implemented with a transmission rate of 64 kb/s. and a quadrature-type modulator is used with the carrier frequency of 900 MHz band. The RAM-type demodulator is used as the differential detector.<>
{"title":"Error performance of pi /2-TFSK 2-bit differential detection over the band-limited multipath interfering mobile radio environments","authors":"J. Horikoshi","doi":"10.1109/VETEC.1990.110359","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110359","url":null,"abstract":"A modulation scheme named pi /2-TFSK shows a superior error performance to MSK (minimum shift keying) in a frequency-selective mobile radio channel. The 2-bit differential detection of pi /2-TFSK with a raised-cosine type premodulation lowpass filter is analyzed under the frequency-selective mobile radio environment, and a better error performance than MSK is demonstrated. These characteristics are confirmed through an experimental simulation in the laboratory. As the frequency-selective fading model a two Rayleigh-fading-wave model with a constant group time delay is adopted. The system is implemented with a transmission rate of 64 kb/s. and a quadrature-type modulator is used with the carrier frequency of 900 MHz band. The RAM-type demodulator is used as the differential detector.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":"39 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":"117092733","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.1990.110371
R. Messaros, F. Seifert
The properties of GMSK (Gaussian premodulation filtered minimum shift keying) in a multipath fading and interference scenario is described. The GMSK signalling scheme is outlined, and the transmitter and receivers are described. The bit error rate (BER) performance is analyzed for measured indoor and outdoor multipath fading channels. BER degradation when using coherent and noncoherent reception is investigated.<>
{"title":"Performance of GMSK-transmission under typical indoor and outdoor channel conditions using coherent and noncoherent reception","authors":"R. Messaros, F. Seifert","doi":"10.1109/VETEC.1990.110371","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110371","url":null,"abstract":"The properties of GMSK (Gaussian premodulation filtered minimum shift keying) in a multipath fading and interference scenario is described. The GMSK signalling scheme is outlined, and the transmitter and receivers are described. The bit error rate (BER) performance is analyzed for measured indoor and outdoor multipath fading channels. BER degradation when using coherent and noncoherent reception is investigated.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":"146 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":"126187205","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.1990.110299
T. Yoshida, M. Kawabe, T. Maeno, C. Takahashi
An adaptive error control scheme suitable for mobile communication systems id described. An error-free high-speed data modem that uses an adaptive error control scheme is developed. Utilizing the error-free modem for which the error control scheme is adapted, a facsimile adapter which makes GIII-facsimile communication possible between a cellular mobile telephone and an office, and between two cellular mobile telephones, is developed. The error-free modem, a facsimile adapter as an example application of this modem, and modem LSIs which are developed for use in the signal converter unit of the error-free modem are described.<>
{"title":"GIII-facsimile adapter for cellular mobile telephone using error control scheme","authors":"T. Yoshida, M. Kawabe, T. Maeno, C. Takahashi","doi":"10.1109/VETEC.1990.110299","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110299","url":null,"abstract":"An adaptive error control scheme suitable for mobile communication systems id described. An error-free high-speed data modem that uses an adaptive error control scheme is developed. Utilizing the error-free modem for which the error control scheme is adapted, a facsimile adapter which makes GIII-facsimile communication possible between a cellular mobile telephone and an office, and between two cellular mobile telephones, is developed. The error-free modem, a facsimile adapter as an example application of this modem, and modem LSIs which are developed for use in the signal converter unit of the error-free modem are described.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":"16 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":"125725626","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.1990.110360
K. Ohno, F. Adachi
Bit error rate (BER) performance improvements achieved by the use of postdetection diversity with selection combining for Nyquist raised cosine filtered quadrature differential phase shift keying (QDPSK) signal transmissions in frequency-selective Rayleigh fading channels are investigated. Theoretical analysis shows that diversity reception can significantly increase the maximum bit rate. If an average BER of 10/sup -4/ is required, a five-fold increase in the tolerable normalized RMS delay spread (RMS delay spread X symbol rate) is possible by using simple two-branch diversity reception. The effects the Nyquist filter roll-off factor have on average BER are also analyzed to show that average BER can be reduced at the cost of a slightly increased bandwidth. Laboratory and field experimental results that support these theoretical results are shown.<>
{"title":"Postdetection diversity reception of QDPSK signals under frequency selective Rayleigh fading","authors":"K. Ohno, F. Adachi","doi":"10.1109/VETEC.1990.110360","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110360","url":null,"abstract":"Bit error rate (BER) performance improvements achieved by the use of postdetection diversity with selection combining for Nyquist raised cosine filtered quadrature differential phase shift keying (QDPSK) signal transmissions in frequency-selective Rayleigh fading channels are investigated. Theoretical analysis shows that diversity reception can significantly increase the maximum bit rate. If an average BER of 10/sup -4/ is required, a five-fold increase in the tolerable normalized RMS delay spread (RMS delay spread X symbol rate) is possible by using simple two-branch diversity reception. The effects the Nyquist filter roll-off factor have on average BER are also analyzed to show that average BER can be reduced at the cost of a slightly increased bandwidth. Laboratory and field experimental results that support these theoretical results are shown.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":"20 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":"127162010","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.1990.110386
J. Chuang
Go-back-n (GBN) and selective repeat (SR) protocols for automatic repeat request (ARQ) protocols are compared in a frequency-nonselective Rayleigh fading channel. The channel coding used is assumed to be for error detection only; therefore, the throughput reduction due to coding is smaller than if the coding were used for error correction. Only practical ARQ protocols that can be implemented in real-time applications with finite-buffering capability are considered. Protocols implemented in software are used in a computer-simulated fading channel to study the throughput of these protocols for data communications. It is found that SR is significantly superior to GBN when fading rate is high; this advantage decreases as fading becomes slower. Error detection combined with ARQ and diversity selection can provide reliable data communications in a Rayleigh fading channel.<>
{"title":"Comparison of two ARO protocols in a Rayleigh fading channel","authors":"J. Chuang","doi":"10.1109/VETEC.1990.110386","DOIUrl":"https://doi.org/10.1109/VETEC.1990.110386","url":null,"abstract":"Go-back-n (GBN) and selective repeat (SR) protocols for automatic repeat request (ARQ) protocols are compared in a frequency-nonselective Rayleigh fading channel. The channel coding used is assumed to be for error detection only; therefore, the throughput reduction due to coding is smaller than if the coding were used for error correction. Only practical ARQ protocols that can be implemented in real-time applications with finite-buffering capability are considered. Protocols implemented in software are used in a computer-simulated fading channel to study the throughput of these protocols for data communications. It is found that SR is significantly superior to GBN when fading rate is high; this advantage decreases as fading becomes slower. Error detection combined with ARQ and diversity selection can provide reliable data communications in a Rayleigh fading channel.<<ETX>>","PeriodicalId":366352,"journal":{"name":"40th IEEE Conference on Vehicular Technology","volume":"1 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":"130457326","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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