Pub Date : 1988-10-23DOI: 10.1109/MILCOM.1988.13359
G. Atkin, M. Lu, K. S. Fung
Uncoded and coded optical pulse position modulation (PPM) systems are compared for both direct and heterodyne detection. Simulations of these systems with different code rates are included, and the gains obtained in the coded cases are reported. By using Reed-Solomon codes, it is seen that the performance of a coded system is improved over an uncoded system in direct detection. As the code rate is reduced, the system performance gets better. Among the three different code rates tested, the code rate of 1/3 seems to be the best choice. The same applies to the heterodyne detection system. When Reed-Solomon codes are applied to a heterodyne system, it is observed that the efficiency of the system improves.<>
{"title":"Performance analysis of Reed-Solomon codes in a slightly dispersive optical PPM system","authors":"G. Atkin, M. Lu, K. S. Fung","doi":"10.1109/MILCOM.1988.13359","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13359","url":null,"abstract":"Uncoded and coded optical pulse position modulation (PPM) systems are compared for both direct and heterodyne detection. Simulations of these systems with different code rates are included, and the gains obtained in the coded cases are reported. By using Reed-Solomon codes, it is seen that the performance of a coded system is improved over an uncoded system in direct detection. As the code rate is reduced, the system performance gets better. Among the three different code rates tested, the code rate of 1/3 seems to be the best choice. The same applies to the heterodyne detection system. When Reed-Solomon codes are applied to a heterodyne system, it is observed that the efficiency of the system improves.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"13 1","pages":"7-12 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82370817","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13421
Jeffrey H. Reed, A. A. Quilici, T. Hsia
The authors examine a type of adaptive filter called a time-dependent adaptive filter (TDAF). A TDAF can effectively deal with the cyclostationary nature of communication signals by changing periodically. It achieves a smaller mean-square error than conventional filter for cyclostationary signals. A frequency-domain TDAF is investigated, and it is shown that it is especially effective for interference rejection applications. Simulation results are presented, showing how cochannel QPSK signals can be separated.<>
{"title":"A frequency domain time-dependent adaptive filter for interference rejection","authors":"Jeffrey H. Reed, A. A. Quilici, T. Hsia","doi":"10.1109/MILCOM.1988.13421","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13421","url":null,"abstract":"The authors examine a type of adaptive filter called a time-dependent adaptive filter (TDAF). A TDAF can effectively deal with the cyclostationary nature of communication signals by changing periodically. It achieves a smaller mean-square error than conventional filter for cyclostationary signals. A frequency-domain TDAF is investigated, and it is shown that it is especially effective for interference rejection applications. Simulation results are presented, showing how cochannel QPSK signals can be separated.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"60 1","pages":"391-397 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84021108","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13373
D. McRae
The 5254B HF serial modem is described. The nature of serial modem technology is discussed along with the manner in which the 5254B operates. The performances of this modem is examined, and future capabilities in this field are considered.<>
{"title":"Advances in HF serial modem technology","authors":"D. McRae","doi":"10.1109/MILCOM.1988.13373","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13373","url":null,"abstract":"The 5254B HF serial modem is described. The nature of serial modem technology is discussed along with the manner in which the 5254B operates. The performances of this modem is examined, and future capabilities in this field are considered.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"46 1","pages":"83-88 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84143664","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13374
P. A. Bello
The author presents performance evaluations for four Rake modems used to communicate over the wideband (e.g. 1 MHz) HF channel. Attention is confined to performance for the nondisturbed HF channel. Consideration is given to the impact of mode Doppler shift and multipath spread due to dispersion. The effects of additive noise, self-noise, and imperfect channel measurements are included. Results are presented for decision-directed, parallel probe, serial probe, and DPSK Rake modems. Performance to within 1-3 dB of the additive white Gaussian noise channel is predicted, depending upon the modem and the channel dispersion, if the Doppler shift of the modem can be tracked to within 0.1 Hz.<>
{"title":"Performance of some Rake modems over the non-disturbed wide band HF channel","authors":"P. A. Bello","doi":"10.1109/MILCOM.1988.13374","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13374","url":null,"abstract":"The author presents performance evaluations for four Rake modems used to communicate over the wideband (e.g. 1 MHz) HF channel. Attention is confined to performance for the nondisturbed HF channel. Consideration is given to the impact of mode Doppler shift and multipath spread due to dispersion. The effects of additive noise, self-noise, and imperfect channel measurements are included. Results are presented for decision-directed, parallel probe, serial probe, and DPSK Rake modems. Performance to within 1-3 dB of the additive white Gaussian noise channel is predicted, depending upon the modem and the channel dispersion, if the Doppler shift of the modem can be tracked to within 0.1 Hz.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"22 1","pages":"89-95 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90507256","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13463
F. Carden, B. Kopp
The authors discuss the use of quantized Euclidean soft-decision maximum-likelihood sequence decoders on trellis-coded 8-PSK communication schemes. A model is developed for the circularly quantized Euclidean decoder, and computer simulations are used to evaluate it. Degradation is determined as a function of the number of sectors used in the circular quantization.<>
{"title":"A quantized Euclidean soft-decision maximum likelihood sequence decoder for TCM","authors":"F. Carden, B. Kopp","doi":"10.1109/MILCOM.1988.13463","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13463","url":null,"abstract":"The authors discuss the use of quantized Euclidean soft-decision maximum-likelihood sequence decoders on trellis-coded 8-PSK communication schemes. A model is developed for the circularly quantized Euclidean decoder, and computer simulations are used to evaluate it. Degradation is determined as a function of the number of sectors used in the circular quantization.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"115 1","pages":"679-682 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80822610","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13466
Tsern-Huei Lee
The author derives the throughput and activity factor for a multichannel ALOHA system under the constraint of limited receiving capability. The deterioration of performance due to lack of receiving devices is shown to be significant. To alleviate the deterioration, a dynamic diversity scheme is proposed whereby all active users and the receiver must agree as to which channels are temporarily abandoned until devices are repaired or replaced.<>
{"title":"Performance analysis of a multi-channel ALOHA system with limited receiving capability","authors":"Tsern-Huei Lee","doi":"10.1109/MILCOM.1988.13466","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13466","url":null,"abstract":"The author derives the throughput and activity factor for a multichannel ALOHA system under the constraint of limited receiving capability. The deterioration of performance due to lack of receiving devices is shown to be significant. To alleviate the deterioration, a dynamic diversity scheme is proposed whereby all active users and the receiver must agree as to which channels are temporarily abandoned until devices are repaired or replaced.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"37 1","pages":"697-701 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80338669","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13402
R. Desourdis, J. Wojtaszek, S.C. Merrill, K. Hernandez
Physical models of a meteor-burst-communication channel (METLINK) and a link simulator (METWAIT) were developed. Validation was performed using data measured on an experimental link in Greenland. METLINK and METWAIT were used to determine the sensitivity of 1000-character message waiting times to antenna pattern, link power margin, and range. This analysis shows that the sensitivity of message waiting times to power margin increases considerably when the link relies on overdense meteors.<>
{"title":"Meteor burst link performance sensitivity to antenna pattern, power margin and range","authors":"R. Desourdis, J. Wojtaszek, S.C. Merrill, K. Hernandez","doi":"10.1109/MILCOM.1988.13402","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13402","url":null,"abstract":"Physical models of a meteor-burst-communication channel (METLINK) and a link simulator (METWAIT) were developed. Validation was performed using data measured on an experimental link in Greenland. METLINK and METWAIT were used to determine the sensitivity of 1000-character message waiting times to antenna pattern, link power margin, and range. This analysis shows that the sensitivity of message waiting times to power margin increases considerably when the link relies on overdense meteors.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"5 1","pages":"257-263 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79351290","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13480
T. Philips, S. Panwar, A. Tantawi
A model of a packet radio network in which transmitters with a transmission range of R units are distributed according to a two-dimensional Poisson point process is examined. It is a widely held belief that an optimal number of nearest neighbors of a transmitter (the magic number) exists that maximizes the throughput of the network. The authors show that no magic number can exist. However, the notion of a magic number is shown to be useful, and an explanation is provided for why computations based on magic numbers give answers that are good in practice.<>
{"title":"Connectivity properties of a mobile packet radio network model","authors":"T. Philips, S. Panwar, A. Tantawi","doi":"10.1109/MILCOM.1988.13480","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13480","url":null,"abstract":"A model of a packet radio network in which transmitters with a transmission range of R units are distributed according to a two-dimensional Poisson point process is examined. It is a widely held belief that an optimal number of nearest neighbors of a transmitter (the magic number) exists that maximizes the throughput of the network. The authors show that no magic number can exist. However, the notion of a magic number is shown to be useful, and an explanation is provided for why computations based on magic numbers give answers that are good in practice.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"35 1","pages":"777-781 vol.3"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85668658","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13439
M.A. Schroeder, K. T. Newport
A methodology that makes use of global- and local-topology-based criteria to enhance the stability of tactical communications networks is presented. The global criteria were described previously, but the local criteria are newly derived. The criteria are used to enhance the topological stability of tactical networks through recursive link reallocation. This process has application to both predeployment and real-time configuration of tactical networks. With its use, tactical communication networks can be augmented to improve overall system survivability by reducing the impact that individual resource losses have on the topological structure of the network.<>
{"title":"Augmenting tactical communications networks to enhance survivability","authors":"M.A. Schroeder, K. T. Newport","doi":"10.1109/MILCOM.1988.13439","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13439","url":null,"abstract":"A methodology that makes use of global- and local-topology-based criteria to enhance the stability of tactical communications networks is presented. The global criteria were described previously, but the local criteria are newly derived. The criteria are used to enhance the topological stability of tactical networks through recursive link reallocation. This process has application to both predeployment and real-time configuration of tactical networks. With its use, tactical communication networks can be augmented to improve overall system survivability by reducing the impact that individual resource losses have on the topological structure of the network.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"66 1","pages":"507-513 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87644685","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13501
J. M. Jacobsmeyer
The author investigates the performance of an adaptive information rate technique that is particularly well suited to the bandwidth-limited meteor burst channel. This technique uses the quadrature amplitude signal sets common to digital radio and is called adaptive QAM. Improvements in throughput that are possible with the proposed approach are examined. The results are pertinent to the use of meteor-burst channels for military applications.<>
{"title":"An adaptive modulation scheme for bandwidth-limited meteor-burst channels","authors":"J. M. Jacobsmeyer","doi":"10.1109/MILCOM.1988.13501","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13501","url":null,"abstract":"The author investigates the performance of an adaptive information rate technique that is particularly well suited to the bandwidth-limited meteor burst channel. This technique uses the quadrature amplitude signal sets common to digital radio and is called adaptive QAM. Improvements in throughput that are possible with the proposed approach are examined. The results are pertinent to the use of meteor-burst channels for military applications.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"324 1","pages":"933-937 vol.3"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75712741","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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