Pub Date : 1991-11-04DOI: 10.1109/MILCOM.1991.258406
J.M. Jacobsmeyer
An alternative approach to the problem of multipath fading on HF ionospheric scatter channels is considered: that of adapting the data rate to the channel conditions. The performance of a simple on/off data rate system is only 4.3 dB shy of non-fading performance. A more sophisticated four-rate (three non-zero rates) trellis-coded system gains 6.7 dB more without interleaving and without bandwidth expansion. At a bit error rate of 10/sup -5/, this is equivalent to 39 dB of coding gain. Implementation problems for adaptive data rate systems include noisy feedback channels, increased overhead, synchronization, sensitivity to propagation delay, and buffer control. It is noted that these problems are challenging, but not insurmountable.<>
{"title":"Adaptive data rate communications for high frequency radio channels","authors":"J.M. Jacobsmeyer","doi":"10.1109/MILCOM.1991.258406","DOIUrl":"https://doi.org/10.1109/MILCOM.1991.258406","url":null,"abstract":"An alternative approach to the problem of multipath fading on HF ionospheric scatter channels is considered: that of adapting the data rate to the channel conditions. The performance of a simple on/off data rate system is only 4.3 dB shy of non-fading performance. A more sophisticated four-rate (three non-zero rates) trellis-coded system gains 6.7 dB more without interleaving and without bandwidth expansion. At a bit error rate of 10/sup -5/, this is equivalent to 39 dB of coding gain. Implementation problems for adaptive data rate systems include noisy feedback channels, increased overhead, synchronization, sensitivity to propagation delay, and buffer control. It is noted that these problems are challenging, but not insurmountable.<<ETX>>","PeriodicalId":212388,"journal":{"name":"MILCOM 91 - Conference record","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128036338","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 : 1991-11-04DOI: 10.1109/MILCOM.1991.258332
M. Deierling, R. Iyer, H. Erwin
The existence of complex modes of behavior has been demonstrated in the dynamics of resource allocation in computational ecosystems. The authors present analysis and simulation results indicating that this behavior can also be expected in communications networks and may generate complex phase transitions in the topological dynamics. Some common wide area network (WAN) architectures have structurally unstable topological dynamics and are vulnerable to random phase transitions induced by statistical noise in the input scenario. Since these two types of phase transitions can induce congestion events with rapid onset and slow recovery, this can lead to extended periods of degraded communications.<>
{"title":"Dynamics of network performance","authors":"M. Deierling, R. Iyer, H. Erwin","doi":"10.1109/MILCOM.1991.258332","DOIUrl":"https://doi.org/10.1109/MILCOM.1991.258332","url":null,"abstract":"The existence of complex modes of behavior has been demonstrated in the dynamics of resource allocation in computational ecosystems. The authors present analysis and simulation results indicating that this behavior can also be expected in communications networks and may generate complex phase transitions in the topological dynamics. Some common wide area network (WAN) architectures have structurally unstable topological dynamics and are vulnerable to random phase transitions induced by statistical noise in the input scenario. Since these two types of phase transitions can induce congestion events with rapid onset and slow recovery, this can lead to extended periods of degraded communications.<<ETX>>","PeriodicalId":212388,"journal":{"name":"MILCOM 91 - Conference record","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127977967","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 : 1991-11-04DOI: 10.1109/MILCOM.1991.258445
H. Paul, D. R. Ayers, P. Shloss
A requirement exists to provide a full duplex, 2.4-kb/s MILSATCOM voice circuits with low probability of intercept and antijam protection to highly mobile tactical users. The authors discuss an EHF manpack terminal design that uses moderate beamwidth antennas to provide this service. The terminal antenna system consists of five transmit/receive pairs of phased array antennas mounted on the faces of a cube. A hybrid inertial motion sensing/antenna step tracking system is used to select the active antenna array and point the selected beam toward the satellite despite the presence of user motion. The recommended terminal design relies on technologies that are currently under development. The realization of a cost-effective implementation is considered feasible within the next five years, but would require continued investment in MMIC (monolithic microwave integrated circuit) phased array technology and manufacturing techniques.<>
{"title":"EHF phased array manpack terminal design","authors":"H. Paul, D. R. Ayers, P. Shloss","doi":"10.1109/MILCOM.1991.258445","DOIUrl":"https://doi.org/10.1109/MILCOM.1991.258445","url":null,"abstract":"A requirement exists to provide a full duplex, 2.4-kb/s MILSATCOM voice circuits with low probability of intercept and antijam protection to highly mobile tactical users. The authors discuss an EHF manpack terminal design that uses moderate beamwidth antennas to provide this service. The terminal antenna system consists of five transmit/receive pairs of phased array antennas mounted on the faces of a cube. A hybrid inertial motion sensing/antenna step tracking system is used to select the active antenna array and point the selected beam toward the satellite despite the presence of user motion. The recommended terminal design relies on technologies that are currently under development. The realization of a cost-effective implementation is considered feasible within the next five years, but would require continued investment in MMIC (monolithic microwave integrated circuit) phased array technology and manufacturing techniques.<<ETX>>","PeriodicalId":212388,"journal":{"name":"MILCOM 91 - Conference record","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115413840","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 : 1991-11-04DOI: 10.1109/MILCOM.1991.258227
A. Mankin
The combination of underlying tactical link and end-to-end protocol in terms of performance has rarely been measured, even for the Department of Defense transport control protocol/Internet protocol (TCP/IP). The author presents a multilayer method for collecting data on this combined performance and analyzing it to provide integrated information on the performance seen by the users application and the underlying network behavior. Four tactical RF links, the defense satellite communications tactical satellite, the fleet satellite, the very small aperture terminal satellite, and the mobile subscriber equipment line of sight radio, were studied during the integrated tactical data network demonstration. The experimental results include effects of asymmetric transmission quality and bit errors. It is concluded that TCP/IP can perform well over tactical RF links, and tuning parameters for TCP and TP4 are derived from the measurements and observations.<>
{"title":"Towards tactical GOSIP: performance of TCP/IP over RF links in the ITDN","authors":"A. Mankin","doi":"10.1109/MILCOM.1991.258227","DOIUrl":"https://doi.org/10.1109/MILCOM.1991.258227","url":null,"abstract":"The combination of underlying tactical link and end-to-end protocol in terms of performance has rarely been measured, even for the Department of Defense transport control protocol/Internet protocol (TCP/IP). The author presents a multilayer method for collecting data on this combined performance and analyzing it to provide integrated information on the performance seen by the users application and the underlying network behavior. Four tactical RF links, the defense satellite communications tactical satellite, the fleet satellite, the very small aperture terminal satellite, and the mobile subscriber equipment line of sight radio, were studied during the integrated tactical data network demonstration. The experimental results include effects of asymmetric transmission quality and bit errors. It is concluded that TCP/IP can perform well over tactical RF links, and tuning parameters for TCP and TP4 are derived from the measurements and observations.<<ETX>>","PeriodicalId":212388,"journal":{"name":"MILCOM 91 - Conference record","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124293605","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 : 1991-11-04DOI: 10.1109/MILCOM.1991.258407
P. Kowalski, T. Geffert, M. Veve
A high-resolution, high-frequency direction finding system for shipboard applications based on the multiple signal classification (MUSIC) algorithm has been developed. The half-rack system has successfully undergone at-sea and pier-side tests on several ship classes, and at several field sites. Using a 3- to 5-m antenna aperture, the system demonstrates groundwave line-of-bearing accuracies of +or-3 degrees over the full HF band (3 to 30 MHz) at shore sites and +or-5 degrees on ships. The system effectively operates against skywave and groundwave signals, calculating the elevation and azimuth angle of the incoming wave front. For shipboard applications, three-element bow and stern antenna arrays overcome the typical field deformations caused by superstructure interactions. A detection and selection algorithm selects the best array based on field uniformity and signal-to-noise ratios. Spatial smoothing and sector search pattern algorithms help to reduce re-radiation effects.<>
{"title":"MUSIC algorithm implementation for shipboard HF radio direction finding","authors":"P. Kowalski, T. Geffert, M. Veve","doi":"10.1109/MILCOM.1991.258407","DOIUrl":"https://doi.org/10.1109/MILCOM.1991.258407","url":null,"abstract":"A high-resolution, high-frequency direction finding system for shipboard applications based on the multiple signal classification (MUSIC) algorithm has been developed. The half-rack system has successfully undergone at-sea and pier-side tests on several ship classes, and at several field sites. Using a 3- to 5-m antenna aperture, the system demonstrates groundwave line-of-bearing accuracies of +or-3 degrees over the full HF band (3 to 30 MHz) at shore sites and +or-5 degrees on ships. The system effectively operates against skywave and groundwave signals, calculating the elevation and azimuth angle of the incoming wave front. For shipboard applications, three-element bow and stern antenna arrays overcome the typical field deformations caused by superstructure interactions. A detection and selection algorithm selects the best array based on field uniformity and signal-to-noise ratios. Spatial smoothing and sector search pattern algorithms help to reduce re-radiation effects.<<ETX>>","PeriodicalId":212388,"journal":{"name":"MILCOM 91 - Conference record","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117108766","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 : 1991-11-04DOI: 10.1109/MILCOM.1991.258462
T. Champion
A technique for digital conferencing over narrowband channels which allows for the representation of multiple simultaneous speakers is proposed. The technique takes advantage of the properties of multirate parametric vocoders (which includes the sinusoidal transform coder and the multiband excitation vocoder, as well as embedded coders). The technique performs signal summation in a manner similar to analog conferences; however, signal summation is deferred to the terminal. To maintain quality for a single speaker while allowing multiple speakers, the technique adaptively allocates channel bandwidth based on the number of speakers to be represented. Development is in progress on a system that allows two simultaneous speakers, although a system for three simultaneous speakers is achievable.<>
{"title":"Multi-speaker conferencing over narrowband channels","authors":"T. Champion","doi":"10.1109/MILCOM.1991.258462","DOIUrl":"https://doi.org/10.1109/MILCOM.1991.258462","url":null,"abstract":"A technique for digital conferencing over narrowband channels which allows for the representation of multiple simultaneous speakers is proposed. The technique takes advantage of the properties of multirate parametric vocoders (which includes the sinusoidal transform coder and the multiband excitation vocoder, as well as embedded coders). The technique performs signal summation in a manner similar to analog conferences; however, signal summation is deferred to the terminal. To maintain quality for a single speaker while allowing multiple speakers, the technique adaptively allocates channel bandwidth based on the number of speakers to be represented. Development is in progress on a system that allows two simultaneous speakers, although a system for three simultaneous speakers is achievable.<<ETX>>","PeriodicalId":212388,"journal":{"name":"MILCOM 91 - Conference record","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117264016","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 : 1991-11-04DOI: 10.1109/MILCOM.1991.258396
T. Jiang
It is suggested that the most important and reasonable parameter of a communication network is the traffic capacity, which might be selected to measure the survivability. It is concluded that the definition of survivability based on traffic flow can be used to evaluate or design a military communication network conveniently. It includes the old definition based on connectivity and is broader in concept. There will be no problem in calculation, because the program is already available. A design of a military communication network using this concept has been performed, showing that the definition is correct.<>
{"title":"A new definition of survivability of communication networks","authors":"T. Jiang","doi":"10.1109/MILCOM.1991.258396","DOIUrl":"https://doi.org/10.1109/MILCOM.1991.258396","url":null,"abstract":"It is suggested that the most important and reasonable parameter of a communication network is the traffic capacity, which might be selected to measure the survivability. It is concluded that the definition of survivability based on traffic flow can be used to evaluate or design a military communication network conveniently. It includes the old definition based on connectivity and is broader in concept. There will be no problem in calculation, because the program is already available. A design of a military communication network using this concept has been performed, showing that the definition is correct.<<ETX>>","PeriodicalId":212388,"journal":{"name":"MILCOM 91 - Conference record","volume":"772 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116412665","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 : 1991-11-04DOI: 10.1109/MILCOM.1991.258456
C. Kchao, G. Stuber
The uplink performance of a digital cellular radio system that uses DS (direct-sequence) CDMA (code division multiple access) is evaluated. Expressions for bit error probability that account for path loss, multipath-fading, multiple-access interference, and background noise are obtained. Three differentially coherent receivers are considered: a multipath rejection receiver, a RAKE receiver with predetection selective diversity combining, and a RAKE receiver with postdetection equal gain combing. Error correction coding is also considered.<>
{"title":"Performance analysis of a single cell direct-sequence mobile radio system","authors":"C. Kchao, G. Stuber","doi":"10.1109/MILCOM.1991.258456","DOIUrl":"https://doi.org/10.1109/MILCOM.1991.258456","url":null,"abstract":"The uplink performance of a digital cellular radio system that uses DS (direct-sequence) CDMA (code division multiple access) is evaluated. Expressions for bit error probability that account for path loss, multipath-fading, multiple-access interference, and background noise are obtained. Three differentially coherent receivers are considered: a multipath rejection receiver, a RAKE receiver with predetection selective diversity combining, and a RAKE receiver with postdetection equal gain combing. Error correction coding is also considered.<<ETX>>","PeriodicalId":212388,"journal":{"name":"MILCOM 91 - Conference record","volume":"114 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122028143","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 : 1991-11-04DOI: 10.1109/MILCOM.1991.258427
T. Frederick, M. Belkerdid, M. Georgiopoulos
The performance of several error control coding schemes for a meteor burst channel is studied via analysis and simulation. These coding strategies are compared using the probability of successful transmission of a fixed size packet through a single burst as a performance measure. The coding methods are compared via simulation for several realizations of meteor burst. It is found that, based on complexity and probability of success, fixed-rate convolutional codes with soft decision Viterbi decoding provide better performance.<>
{"title":"Error control coding for meteor burst channels","authors":"T. Frederick, M. Belkerdid, M. Georgiopoulos","doi":"10.1109/MILCOM.1991.258427","DOIUrl":"https://doi.org/10.1109/MILCOM.1991.258427","url":null,"abstract":"The performance of several error control coding schemes for a meteor burst channel is studied via analysis and simulation. These coding strategies are compared using the probability of successful transmission of a fixed size packet through a single burst as a performance measure. The coding methods are compared via simulation for several realizations of meteor burst. It is found that, based on complexity and probability of success, fixed-rate convolutional codes with soft decision Viterbi decoding provide better performance.<<ETX>>","PeriodicalId":212388,"journal":{"name":"MILCOM 91 - Conference record","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124026918","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 : 1991-11-04DOI: 10.1109/MILCOM.1991.258444
J. Lee
A compact, high-performance, dual-band antenna has been developed for use with ASCAMP (advanced single-channel antijam man-portable). It consists of a compact feed with an elliptical subreflector which produces the required focus ring for a displaced axis parabolic reflector. The main reflector of the antenna, which weights 2.6 pounds, is made up of six lightweight petals which can be separated and nested for easy portability. Because the petals in the assembled antenna do not mate up perfectly, the aperture illumination efficiency of the antenna is reduced relative to a single-piece reflector by 0.9 dB and 0.2 dB at 44.5 GHz and 20.7 GHz, respectively. Even with this added loss, however, the efficiency of the final design is better than 53% in both frequency bands. The author discusses the considerations which led to the final antenna design, describes the antenna's mechanical configuration, and presents measured performance test results.<>
{"title":"A compact EHF dual-frequency antenna for ASCAMP","authors":"J. Lee","doi":"10.1109/MILCOM.1991.258444","DOIUrl":"https://doi.org/10.1109/MILCOM.1991.258444","url":null,"abstract":"A compact, high-performance, dual-band antenna has been developed for use with ASCAMP (advanced single-channel antijam man-portable). It consists of a compact feed with an elliptical subreflector which produces the required focus ring for a displaced axis parabolic reflector. The main reflector of the antenna, which weights 2.6 pounds, is made up of six lightweight petals which can be separated and nested for easy portability. Because the petals in the assembled antenna do not mate up perfectly, the aperture illumination efficiency of the antenna is reduced relative to a single-piece reflector by 0.9 dB and 0.2 dB at 44.5 GHz and 20.7 GHz, respectively. Even with this added loss, however, the efficiency of the final design is better than 53% in both frequency bands. The author discusses the considerations which led to the final antenna design, describes the antenna's mechanical configuration, and presents measured performance test results.<<ETX>>","PeriodicalId":212388,"journal":{"name":"MILCOM 91 - Conference record","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125883279","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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