Pub Date : 1992-10-11DOI: 10.1109/MILCOM.1992.244041
L. D. Gottesman, L. Milstein
The performance of a direct-sequence spread-spectrum coarse acquisition system operating in the presence of narrowband interference is considered under two processing strategies. The first strategy uses the arbitrary phase present at the input as the reference phase for all correlation operations, while the second uses a prediction filter to suppress narrowband interference. Performance is considered for both short and long spreading codes when either sinusoidal or narrowband Gaussian interference is present in the input signal. While the performance using the first method is consistently better when the same reference phase is used, the overall performance is usually superior under the second method, because an optimal reference phase may be chosen.<>
{"title":"Processing direct-sequence spread-spectrum signals for improved acquisition performance in the presence of strong narrow-band interference","authors":"L. D. Gottesman, L. Milstein","doi":"10.1109/MILCOM.1992.244041","DOIUrl":"https://doi.org/10.1109/MILCOM.1992.244041","url":null,"abstract":"The performance of a direct-sequence spread-spectrum coarse acquisition system operating in the presence of narrowband interference is considered under two processing strategies. The first strategy uses the arbitrary phase present at the input as the reference phase for all correlation operations, while the second uses a prediction filter to suppress narrowband interference. Performance is considered for both short and long spreading codes when either sinusoidal or narrowband Gaussian interference is present in the input signal. While the performance using the first method is consistently better when the same reference phase is used, the overall performance is usually superior under the second method, because an optimal reference phase may be chosen.<<ETX>>","PeriodicalId":394587,"journal":{"name":"MILCOM 92 Conference Record","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115381166","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 : 1992-10-11DOI: 10.1109/MILCOM.1992.244144
B. Serenelli, T. Leisher
It is pointed out that security at the network layer cannot provide application-specific services associated with electronic mail such as signed receipts and digital signatures. These deficiencies can be remedied by providing end user to end user security where mail messages are black (protected/encrypted) at all intermediate points. The authors describe the approach and implementation taken in building such a mail security device. Mail messages are protected along the entire path from originator to recipient. The messages are protected during storage and processing at all intermediate points. the security can be implemented independently of the network layer architecture or a network layer security device. The key distribution technique is suitable for client-server architectures such as electronic mail, where the number of users is large and connectivity is diverse.<>
{"title":"Securing electronic mail systems","authors":"B. Serenelli, T. Leisher","doi":"10.1109/MILCOM.1992.244144","DOIUrl":"https://doi.org/10.1109/MILCOM.1992.244144","url":null,"abstract":"It is pointed out that security at the network layer cannot provide application-specific services associated with electronic mail such as signed receipts and digital signatures. These deficiencies can be remedied by providing end user to end user security where mail messages are black (protected/encrypted) at all intermediate points. The authors describe the approach and implementation taken in building such a mail security device. Mail messages are protected along the entire path from originator to recipient. The messages are protected during storage and processing at all intermediate points. the security can be implemented independently of the network layer architecture or a network layer security device. The key distribution technique is suitable for client-server architectures such as electronic mail, where the number of users is large and connectivity is diverse.<<ETX>>","PeriodicalId":394587,"journal":{"name":"MILCOM 92 Conference Record","volume":"16 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120859079","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 : 1992-10-11DOI: 10.1109/MILCOM.1992.244129
Ikchan Kim, R. Scholtz
The authors describe adaptive threshold control algorithms for the detection of a header in an unslotted centralized packet radio system with common direct-sequence spread-spectrum modulation. Two threshold control strategies, namely, the fixed-maximum-delay (FMD) strategy and the fixed-sample-size (FSS) strategy, are analyzed for two distinct types of false-alarm events, namely, false-alarm on multiple access noise and false-alarm on a header prefix. These strategies are based on an estimate of the total noise power in the receiver. The FSS strategy achieves constant false-alarm rate on sidelobes without prior knowledge of the number of active transmitting radios. The FMD strategy achieves nearly constant false-alarm rate on sidelobes with derived knowledge of the average number of active transmitting radios. Both strategies reduce the dynamic range of the false-alarm rate on a header prefix considerably.<>
{"title":"Comparisons of adaptive threshold control algorithms for unslotted common-spreading-code packet-radio networks","authors":"Ikchan Kim, R. Scholtz","doi":"10.1109/MILCOM.1992.244129","DOIUrl":"https://doi.org/10.1109/MILCOM.1992.244129","url":null,"abstract":"The authors describe adaptive threshold control algorithms for the detection of a header in an unslotted centralized packet radio system with common direct-sequence spread-spectrum modulation. Two threshold control strategies, namely, the fixed-maximum-delay (FMD) strategy and the fixed-sample-size (FSS) strategy, are analyzed for two distinct types of false-alarm events, namely, false-alarm on multiple access noise and false-alarm on a header prefix. These strategies are based on an estimate of the total noise power in the receiver. The FSS strategy achieves constant false-alarm rate on sidelobes without prior knowledge of the number of active transmitting radios. The FMD strategy achieves nearly constant false-alarm rate on sidelobes with derived knowledge of the average number of active transmitting radios. Both strategies reduce the dynamic range of the false-alarm rate on a header prefix considerably.<<ETX>>","PeriodicalId":394587,"journal":{"name":"MILCOM 92 Conference Record","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124806254","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 : 1992-10-11DOI: 10.1109/MILCOM.1992.244020
Y. Park, C. Un, Sang Chul Lee
The authors propose a modified flooding algorithm with minimum first-derivative length (MFDL) path for a tactical circuit-switched grid network with a maximum of four links and two priority classes of voice traffic. They consider the minimization of average end-to-end blocking probability, and study the blocking performance of the modified flooding algorithm and the flood search algorithm. They also suggest a decision rule for the search message propagation scheme and analyze the signaling traffic load of the algorithm. It is found that with the same or lower cost of switch processor loading and call set-up time as compared to the flood search algorithm, the modified flooding algorithm provides the shortest path on the basis of blocking probability. Therefore, its use can improve the blocking performance of a circuit-switched network.<>
{"title":"Performance analysis of flood search algorithm with MFDL path in circuit-switched networks","authors":"Y. Park, C. Un, Sang Chul Lee","doi":"10.1109/MILCOM.1992.244020","DOIUrl":"https://doi.org/10.1109/MILCOM.1992.244020","url":null,"abstract":"The authors propose a modified flooding algorithm with minimum first-derivative length (MFDL) path for a tactical circuit-switched grid network with a maximum of four links and two priority classes of voice traffic. They consider the minimization of average end-to-end blocking probability, and study the blocking performance of the modified flooding algorithm and the flood search algorithm. They also suggest a decision rule for the search message propagation scheme and analyze the signaling traffic load of the algorithm. It is found that with the same or lower cost of switch processor loading and call set-up time as compared to the flood search algorithm, the modified flooding algorithm provides the shortest path on the basis of blocking probability. Therefore, its use can improve the blocking performance of a circuit-switched network.<<ETX>>","PeriodicalId":394587,"journal":{"name":"MILCOM 92 Conference Record","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115036951","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 : 1992-10-11DOI: 10.1109/MILCOM.1992.244037
K. Bakhru, A. Sorgi
A spread spectrum fast frequency hopping data link under a hostile jamming environment requires clever modulation approaches to achieve high ranging accuracy while simultaneously transmitting low command-type data rates. Sequentially balanced modulated achieves this goal using a simple hardware implementation while maintaining both continuous and noncontinuous burst-type operation. Both range and data are determined using a vector phase comparison technique. The modulated waveform offers the range accuracy obtainable with tone phase comparison techniques and is compatible with frequency hopping in spread spectrum systems and provides performance superior to that of schemes using direct sequence PN.<>
{"title":"Ranging and bit error rate performance of a fast frequency hopping data link using sequentially balanced modulation","authors":"K. Bakhru, A. Sorgi","doi":"10.1109/MILCOM.1992.244037","DOIUrl":"https://doi.org/10.1109/MILCOM.1992.244037","url":null,"abstract":"A spread spectrum fast frequency hopping data link under a hostile jamming environment requires clever modulation approaches to achieve high ranging accuracy while simultaneously transmitting low command-type data rates. Sequentially balanced modulated achieves this goal using a simple hardware implementation while maintaining both continuous and noncontinuous burst-type operation. Both range and data are determined using a vector phase comparison technique. The modulated waveform offers the range accuracy obtainable with tone phase comparison techniques and is compatible with frequency hopping in spread spectrum systems and provides performance superior to that of schemes using direct sequence PN.<<ETX>>","PeriodicalId":394587,"journal":{"name":"MILCOM 92 Conference Record","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115046958","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 : 1992-10-11DOI: 10.1109/MILCOM.1992.243959
F. Gong, Gurudatta M. Parulkar
The authors believe that a pipelined televisualization model is suitable for efficient implementation of most visualization applications. In order to support this model over high-speed networks, they are developing a segment streaming interprocess communication mechanism within the Axon communication architecture. Important aspects of this effort include the segment streaming paradigm which supports low-overhead communication as well as concurrency between the communication and local computation; a two-level flow control method that provides interstage flow control and ensures that the transport level is conforming to the rate agreement with the underlying network; and an application-oriented error control method which allows error control to be optimized for different applications.<>
{"title":"Segment streaming for efficient pipelined televisualization","authors":"F. Gong, Gurudatta M. Parulkar","doi":"10.1109/MILCOM.1992.243959","DOIUrl":"https://doi.org/10.1109/MILCOM.1992.243959","url":null,"abstract":"The authors believe that a pipelined televisualization model is suitable for efficient implementation of most visualization applications. In order to support this model over high-speed networks, they are developing a segment streaming interprocess communication mechanism within the Axon communication architecture. Important aspects of this effort include the segment streaming paradigm which supports low-overhead communication as well as concurrency between the communication and local computation; a two-level flow control method that provides interstage flow control and ensures that the transport level is conforming to the rate agreement with the underlying network; and an application-oriented error control method which allows error control to be optimized for different applications.<<ETX>>","PeriodicalId":394587,"journal":{"name":"MILCOM 92 Conference Record","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116423975","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 : 1992-10-11DOI: 10.1109/MILCOM.1992.244043
C. Pateros, G. Saulnier
The authors analyze the bit error rate (BER) performance of the adaptive correlator in a complex channel with both multipath and narrowband interference. They extend previous work by presenting analytical BER expressions and results for narrowband (filtered noise) interference. The adaptive correlator is shown to be capable of removing relatively wideband interference in the transmission bandwidth. This is due to the fact that the correlator becomes a finite impulse response (FIR) filter with a deep notch in the interfering band. As the length of the spreading code increases, the FIR filter length will also increase, thus increasing the correlator's ability to remove interference. The error propagation of the least-mean-square (LMS) adaptive algorithm is shown, and is seen to be significant at high bit error rates when a large convergence factor is used.<>
{"title":"Adaptive correlator receiver performance in direct sequence spread spectrum communication","authors":"C. Pateros, G. Saulnier","doi":"10.1109/MILCOM.1992.244043","DOIUrl":"https://doi.org/10.1109/MILCOM.1992.244043","url":null,"abstract":"The authors analyze the bit error rate (BER) performance of the adaptive correlator in a complex channel with both multipath and narrowband interference. They extend previous work by presenting analytical BER expressions and results for narrowband (filtered noise) interference. The adaptive correlator is shown to be capable of removing relatively wideband interference in the transmission bandwidth. This is due to the fact that the correlator becomes a finite impulse response (FIR) filter with a deep notch in the interfering band. As the length of the spreading code increases, the FIR filter length will also increase, thus increasing the correlator's ability to remove interference. The error propagation of the least-mean-square (LMS) adaptive algorithm is shown, and is seen to be significant at high bit error rates when a large convergence factor is used.<<ETX>>","PeriodicalId":394587,"journal":{"name":"MILCOM 92 Conference Record","volume":"143 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122346872","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 : 1992-10-11DOI: 10.1109/MILCOM.1992.244018
J. Baras, T. Charuhas
The authors describe a generic object-oriented software environment for the simulation and management of hybrid communication networks (satellite and terrestrial), currently under development. Referred to as a systems engineering workstation for hybrid networks, the environment will have the capability to model such networks in a totally object-oriented way and link to network performance evaluation modules. Satellites are treated both as electronic/mechanical systems and as communication nodes. Great flexibility is allowed in defining the various components of the satellite, including its type, onboard processing capabilities, bandwidth, multiple access scheme, and linkage to terrestrial networks. The authors show the system's flexibility in studying combined adaptive routing and access for large, hybrid voice-data networks.<>
{"title":"Hybrid (satellite and terrestrial) communication networks: object oriented generic tools for simulation and management","authors":"J. Baras, T. Charuhas","doi":"10.1109/MILCOM.1992.244018","DOIUrl":"https://doi.org/10.1109/MILCOM.1992.244018","url":null,"abstract":"The authors describe a generic object-oriented software environment for the simulation and management of hybrid communication networks (satellite and terrestrial), currently under development. Referred to as a systems engineering workstation for hybrid networks, the environment will have the capability to model such networks in a totally object-oriented way and link to network performance evaluation modules. Satellites are treated both as electronic/mechanical systems and as communication nodes. Great flexibility is allowed in defining the various components of the satellite, including its type, onboard processing capabilities, bandwidth, multiple access scheme, and linkage to terrestrial networks. The authors show the system's flexibility in studying combined adaptive routing and access for large, hybrid voice-data networks.<<ETX>>","PeriodicalId":394587,"journal":{"name":"MILCOM 92 Conference Record","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122155716","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 : 1992-10-11DOI: 10.1109/MILCOM.1992.244139
M. K. Wyche
The author presents the development of importance sampling function blocks for the Signal Processing WorkSystem (SPW) simulation tool. The derivation and implementation of SPW blocks for both conventional and improved importance sampling techniques are discussed. Conventional importance sampling provides improvement in the simulation times for linear systems that contain little or no memory. Improved importance sampling reduces the simulation time required independently of memory length. The bit-error-rate (BER) performance of a baseband communication system is analyzed using these new blocks in order to quantify the improvement in simulation time using importance sampling as opposed to direct Monte-Carlo simulation.<>
{"title":"Implementation of importance sampling techniques using the Signal Processing WorkSystem (SPW)","authors":"M. K. Wyche","doi":"10.1109/MILCOM.1992.244139","DOIUrl":"https://doi.org/10.1109/MILCOM.1992.244139","url":null,"abstract":"The author presents the development of importance sampling function blocks for the Signal Processing WorkSystem (SPW) simulation tool. The derivation and implementation of SPW blocks for both conventional and improved importance sampling techniques are discussed. Conventional importance sampling provides improvement in the simulation times for linear systems that contain little or no memory. Improved importance sampling reduces the simulation time required independently of memory length. The bit-error-rate (BER) performance of a baseband communication system is analyzed using these new blocks in order to quantify the improvement in simulation time using importance sampling as opposed to direct Monte-Carlo simulation.<<ETX>>","PeriodicalId":394587,"journal":{"name":"MILCOM 92 Conference Record","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123490742","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 : 1992-10-11DOI: 10.1109/MILCOM.1992.244031
P. Weissler, C.-J. Wang
The authors investigate the possibility of using an artificial neural network as an adaptive message router to provide optimal or near-optimal routing paths. Two different neural network architectures are implemented and tested against a network simulator to ascertain if their performance is adequate to allow them to be used as routing controllers in a network. A network simulator was written to investigate the performance of the JEB net of Jensen, Eshera, and Barash (1990) and the Hopfield net in routing messages. The results obtained using the enhanced JEB network show that the problem of optimal message routing can successfully by solved through the application of neural networks.<>
{"title":"The use of artificial neural networks for optimal message routing","authors":"P. Weissler, C.-J. Wang","doi":"10.1109/MILCOM.1992.244031","DOIUrl":"https://doi.org/10.1109/MILCOM.1992.244031","url":null,"abstract":"The authors investigate the possibility of using an artificial neural network as an adaptive message router to provide optimal or near-optimal routing paths. Two different neural network architectures are implemented and tested against a network simulator to ascertain if their performance is adequate to allow them to be used as routing controllers in a network. A network simulator was written to investigate the performance of the JEB net of Jensen, Eshera, and Barash (1990) and the Hopfield net in routing messages. The results obtained using the enhanced JEB network show that the problem of optimal message routing can successfully by solved through the application of neural networks.<<ETX>>","PeriodicalId":394587,"journal":{"name":"MILCOM 92 Conference Record","volume":"209 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114091877","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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