Pub Date : 1994-10-02DOI: 10.1109/MILCOM.1994.473826
J. H. Brundage
There is a new and emerging technology that will cause us to expand the acronym of C/sup 4/I. This new area is video. Video on the battlefield is a reality. Video is defined primarily to be videoteleconferencing, but includes imagery (combat camera included) as well. The present paper only addresses the videoteleconferencing capability for the warrior. Because of the importance that video will have to the commander in the years to come, it is now time to update the acronym C/sup 4/I to C4IV with the "V" standing for video. To demonstrate the importance of video to the warrior and commander the author concentrates on the TACCIMS video implementation in the Republic of Korea for the Combined Forces Command.<>
{"title":"Use of video-teleconferencing in tactical operations","authors":"J. H. Brundage","doi":"10.1109/MILCOM.1994.473826","DOIUrl":"https://doi.org/10.1109/MILCOM.1994.473826","url":null,"abstract":"There is a new and emerging technology that will cause us to expand the acronym of C/sup 4/I. This new area is video. Video on the battlefield is a reality. Video is defined primarily to be videoteleconferencing, but includes imagery (combat camera included) as well. The present paper only addresses the videoteleconferencing capability for the warrior. Because of the importance that video will have to the commander in the years to come, it is now time to update the acronym C/sup 4/I to C4IV with the \"V\" standing for video. To demonstrate the importance of video to the warrior and commander the author concentrates on the TACCIMS video implementation in the Republic of Korea for the Combined Forces Command.<<ETX>>","PeriodicalId":337873,"journal":{"name":"Proceedings of MILCOM '94","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1994-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115713376","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 : 1994-10-02DOI: 10.1109/MILCOM.1994.473895
P. Wei, J. Zeidler, W. Ku
It has been proposed that CDMA systems can be assigned to spectral bands which are presently occupied by narrowband users to further increase spectral capacity. Such CDMA overlay systems could provide new options for efficient utilization of the spectrum with minimal disruption to existing narrowband users, especially if adaptive interference suppression techniques are utilized in the spread spectrum receiver. The bit error rate (BER) performance of the mobile-to-base link of a CDMA system for a single narrowband user which occupies a significant portion of the CDMA bandwidth is considered to evaluate the performance of the adaptive filtering. It is shown that adaptive filtering provides a significant improvement when the CDMA and narrowband powers are of the same order. The dependence of the BER on the filter order, the bandwidth of the interference, and its center frequency relative to the CDMA carrier frequency are demonstrated.<>
{"title":"Adaptive interference suppression for CDMA overlay systems","authors":"P. Wei, J. Zeidler, W. Ku","doi":"10.1109/MILCOM.1994.473895","DOIUrl":"https://doi.org/10.1109/MILCOM.1994.473895","url":null,"abstract":"It has been proposed that CDMA systems can be assigned to spectral bands which are presently occupied by narrowband users to further increase spectral capacity. Such CDMA overlay systems could provide new options for efficient utilization of the spectrum with minimal disruption to existing narrowband users, especially if adaptive interference suppression techniques are utilized in the spread spectrum receiver. The bit error rate (BER) performance of the mobile-to-base link of a CDMA system for a single narrowband user which occupies a significant portion of the CDMA bandwidth is considered to evaluate the performance of the adaptive filtering. It is shown that adaptive filtering provides a significant improvement when the CDMA and narrowband powers are of the same order. The dependence of the BER on the filter order, the bandwidth of the interference, and its center frequency relative to the CDMA carrier frequency are demonstrated.<<ETX>>","PeriodicalId":337873,"journal":{"name":"Proceedings of MILCOM '94","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1994-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117140314","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 : 1994-10-02DOI: 10.1109/MILCOM.1994.474024
T. O'Donnell, J. Simmers, H. Southall, T. Klemas
The goal of neural beamforming is to design neural processing algorithms which adapt to low cost phased array antennas, even when they behave non-linearly, are imperfectly manufactured, or become degraded. Neural beamforming techniques can decrease antenna manufacturing and maintenance costs, and increase mission time and performance before repair. In this paper, we present a neural network architecture which performs signal detection and direction finding despite antenna degradations and non-linear behavior. We present the network's detection and direction-finding (DF) performance at various signal-to-noise ratios (SNRs) and compare it's DF accuracy to a monopulse technique, with and without calibration.<>
{"title":"Neural beamforming for signal detection and location","authors":"T. O'Donnell, J. Simmers, H. Southall, T. Klemas","doi":"10.1109/MILCOM.1994.474024","DOIUrl":"https://doi.org/10.1109/MILCOM.1994.474024","url":null,"abstract":"The goal of neural beamforming is to design neural processing algorithms which adapt to low cost phased array antennas, even when they behave non-linearly, are imperfectly manufactured, or become degraded. Neural beamforming techniques can decrease antenna manufacturing and maintenance costs, and increase mission time and performance before repair. In this paper, we present a neural network architecture which performs signal detection and direction finding despite antenna degradations and non-linear behavior. We present the network's detection and direction-finding (DF) performance at various signal-to-noise ratios (SNRs) and compare it's DF accuracy to a monopulse technique, with and without calibration.<<ETX>>","PeriodicalId":337873,"journal":{"name":"Proceedings of MILCOM '94","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1994-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127115555","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 : 1994-10-02DOI: 10.1109/MILCOM.1994.473897
P. Tsakalides, C. Nikias
A new robust beamformer, based on the Cauchy additive noise assumption, is introduced. The maximum likelihood approach is used for the bearing estimation of multiple sources from a set of snapshots when the interference is impulsive in nature. It is shown that the Cauchy receiver greatly outperforms the Gaussian receiver in a wide variety of non-Gaussian noise environments, and performs comparably to the Gaussian receiver when the additive noise is Gaussian. The Cramer-Rao bound on the estimation error variance is derived, and the robustness of the Cauchy beamformer in a wide range of impulsive interference environments is demonstrated via simulation experiments.<>
{"title":"Maximum likelihood localization of sources in noise modeled as a Cauchy process","authors":"P. Tsakalides, C. Nikias","doi":"10.1109/MILCOM.1994.473897","DOIUrl":"https://doi.org/10.1109/MILCOM.1994.473897","url":null,"abstract":"A new robust beamformer, based on the Cauchy additive noise assumption, is introduced. The maximum likelihood approach is used for the bearing estimation of multiple sources from a set of snapshots when the interference is impulsive in nature. It is shown that the Cauchy receiver greatly outperforms the Gaussian receiver in a wide variety of non-Gaussian noise environments, and performs comparably to the Gaussian receiver when the additive noise is Gaussian. The Cramer-Rao bound on the estimation error variance is derived, and the robustness of the Cauchy beamformer in a wide range of impulsive interference environments is demonstrated via simulation experiments.<<ETX>>","PeriodicalId":337873,"journal":{"name":"Proceedings of MILCOM '94","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1994-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127207452","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 : 1994-10-02DOI: 10.1109/MILCOM.1994.473848
C. Balanis, Weimin Sun, P.A. Tirkas, G. Barber
The Advanced Helicopter Electromagnetics (AHE) was initiated at Arizona State University on January 1, 1990, to address research needs on developing analytical and measurement methods for helicopter EM applications. The AHE program is a coalition of research and education efforts supported by aerospace industry, federal government agencies and state government. The objective of the AHE program was to develop analytical methods and modelings of antennas on metallic and non-metallic bodies for advanced helicopter applications and to facilitate technology transfer through industry, government and university. Under the support of the AHE members and the joint effort of the research team, significant progress has been achieved. The research effort has focused on practical helicopter electromagnetic problems, such as antenna pattern modeling and prediction, composite materials, HF antennas, conformal antennas for UHF and possibly VHF, and scale model measurements. The paper provides a brief review of the AHE program through representative examples of some of the problems that were investigated.<>
{"title":"Advanced Helicopter Electromagnetics: industry, government and university","authors":"C. Balanis, Weimin Sun, P.A. Tirkas, G. Barber","doi":"10.1109/MILCOM.1994.473848","DOIUrl":"https://doi.org/10.1109/MILCOM.1994.473848","url":null,"abstract":"The Advanced Helicopter Electromagnetics (AHE) was initiated at Arizona State University on January 1, 1990, to address research needs on developing analytical and measurement methods for helicopter EM applications. The AHE program is a coalition of research and education efforts supported by aerospace industry, federal government agencies and state government. The objective of the AHE program was to develop analytical methods and modelings of antennas on metallic and non-metallic bodies for advanced helicopter applications and to facilitate technology transfer through industry, government and university. Under the support of the AHE members and the joint effort of the research team, significant progress has been achieved. The research effort has focused on practical helicopter electromagnetic problems, such as antenna pattern modeling and prediction, composite materials, HF antennas, conformal antennas for UHF and possibly VHF, and scale model measurements. The paper provides a brief review of the AHE program through representative examples of some of the problems that were investigated.<<ETX>>","PeriodicalId":337873,"journal":{"name":"Proceedings of MILCOM '94","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1994-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125040673","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 : 1994-10-02DOI: 10.1109/MILCOM.1994.473815
J. An, M. Chen
To evaluate the system performance for mobile satellite communications, it is necessary to take into account the effects of channel impairments by quantitative simulations. Although multipath fading is less destructive to signal propagation than in the case of land mobile radio, channel characterization is still of interest to system planners and designers. The research reported in the paper has resulted in the development of a Markov 3-state stochastic channel model that is useful in testing various digital modulation, channel coding, and receiver diversity designs. A mathematical algorithm is used to generate the Rayleigh fading, Rician fading, and log-normal fading signals which are subsequently used to realize the proposed channel model in cooperation with a linear combination of probabilities of state occurrence and state transition. This developed channel model has been successfully implemented in a TMS320C30 microprocessor to provide a real-time simulation capability. The bit-error-rate (BER) performance of /spl pi//4DQPSK modulation, with I/Q coherent detection has been tested using the system.<>
{"title":"Simulation techniques for mobile satellite channel","authors":"J. An, M. Chen","doi":"10.1109/MILCOM.1994.473815","DOIUrl":"https://doi.org/10.1109/MILCOM.1994.473815","url":null,"abstract":"To evaluate the system performance for mobile satellite communications, it is necessary to take into account the effects of channel impairments by quantitative simulations. Although multipath fading is less destructive to signal propagation than in the case of land mobile radio, channel characterization is still of interest to system planners and designers. The research reported in the paper has resulted in the development of a Markov 3-state stochastic channel model that is useful in testing various digital modulation, channel coding, and receiver diversity designs. A mathematical algorithm is used to generate the Rayleigh fading, Rician fading, and log-normal fading signals which are subsequently used to realize the proposed channel model in cooperation with a linear combination of probabilities of state occurrence and state transition. This developed channel model has been successfully implemented in a TMS320C30 microprocessor to provide a real-time simulation capability. The bit-error-rate (BER) performance of /spl pi//4DQPSK modulation, with I/Q coherent detection has been tested using the system.<<ETX>>","PeriodicalId":337873,"journal":{"name":"Proceedings of MILCOM '94","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1994-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116435677","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 : 1994-10-02DOI: 10.1109/MILCOM.1994.473983
J. Padgett
Most capacity analyses of frequency reuse wireless communication systems assume either fixed channel sets assigned to specific base stations (the traditional cellular model), or some type of dynamic channel assignment (DCA) in a centrally controlled, coordinated system. Such models accurately describe "licensed" systems such as cellular, in which a single system or service provider has exclusive control over a block of spectrum. However, they are inadequate for analysis of systems operating in the "unlicensed" environment, in which multiple systems may share spectrum without any centralized coordination. The model developed is designed for analyzing capacity in such a situation. Cochannel and adjacent-channel interference sources are assumed to be randomly-distributed over area, and possibly on multiple floors for in-building operation. The model is extremely flexible and can be easily adapted to a wide variety of conditions and system configurations. It is intended as an analytical tool, rather than a detailed system simulation, and can be used for fast front-end analysis of system capacity and air interface design tradeoffs. Several example calculations are given and shown to agree well with results of other published studies that use different models.<>
{"title":"Capacity analysis for unlicensed wireless communications","authors":"J. Padgett","doi":"10.1109/MILCOM.1994.473983","DOIUrl":"https://doi.org/10.1109/MILCOM.1994.473983","url":null,"abstract":"Most capacity analyses of frequency reuse wireless communication systems assume either fixed channel sets assigned to specific base stations (the traditional cellular model), or some type of dynamic channel assignment (DCA) in a centrally controlled, coordinated system. Such models accurately describe \"licensed\" systems such as cellular, in which a single system or service provider has exclusive control over a block of spectrum. However, they are inadequate for analysis of systems operating in the \"unlicensed\" environment, in which multiple systems may share spectrum without any centralized coordination. The model developed is designed for analyzing capacity in such a situation. Cochannel and adjacent-channel interference sources are assumed to be randomly-distributed over area, and possibly on multiple floors for in-building operation. The model is extremely flexible and can be easily adapted to a wide variety of conditions and system configurations. It is intended as an analytical tool, rather than a detailed system simulation, and can be used for fast front-end analysis of system capacity and air interface design tradeoffs. Several example calculations are given and shown to agree well with results of other published studies that use different models.<<ETX>>","PeriodicalId":337873,"journal":{"name":"Proceedings of MILCOM '94","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1994-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121852797","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 : 1994-10-02DOI: 10.1109/MILCOM.1994.474016
C. Rîpă
The reliability of the public switched network (PSN) is an important national interest. Government telecommunications users maintain a keen interest in this area since a high percentage of federal traffic transits the PSN. Further, a reliable, secure, service-rich, high performance PSN is extremely important to our national economic performance since telecommunications is at the very heart of business performance and productivity. Fulfilling this challenge and meeting customer service expectations does not occur by chance but is the result of carefully planned service initiatives and effective operations support tools. These attributes will also be extremely important to ensuring the integrity of the evolving national information infrastructure (NII).<>
{"title":"Network reliability: the cornerstone of the telecommunications business","authors":"C. Rîpă","doi":"10.1109/MILCOM.1994.474016","DOIUrl":"https://doi.org/10.1109/MILCOM.1994.474016","url":null,"abstract":"The reliability of the public switched network (PSN) is an important national interest. Government telecommunications users maintain a keen interest in this area since a high percentage of federal traffic transits the PSN. Further, a reliable, secure, service-rich, high performance PSN is extremely important to our national economic performance since telecommunications is at the very heart of business performance and productivity. Fulfilling this challenge and meeting customer service expectations does not occur by chance but is the result of carefully planned service initiatives and effective operations support tools. These attributes will also be extremely important to ensuring the integrity of the evolving national information infrastructure (NII).<<ETX>>","PeriodicalId":337873,"journal":{"name":"Proceedings of MILCOM '94","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1994-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122171800","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 : 1994-10-02DOI: 10.1109/MILCOM.1994.473841
G. Tsihrintzis, C. Nikias
We develop a receiver which detects impulsive stochastic transients superimposed on Gaussian background noise and show that the new detector outperforms existing square- and /spl nu//sup th/-law detectors. To derive the receiver, we first study the structure of the probability density function (pdf) of random variables which are formed as the sum of two or more independent, symmetric stable random variables of different characteristic exponents.<>
{"title":"On the detection of impulsive stochastic transients over background noise","authors":"G. Tsihrintzis, C. Nikias","doi":"10.1109/MILCOM.1994.473841","DOIUrl":"https://doi.org/10.1109/MILCOM.1994.473841","url":null,"abstract":"We develop a receiver which detects impulsive stochastic transients superimposed on Gaussian background noise and show that the new detector outperforms existing square- and /spl nu//sup th/-law detectors. To derive the receiver, we first study the structure of the probability density function (pdf) of random variables which are formed as the sum of two or more independent, symmetric stable random variables of different characteristic exponents.<<ETX>>","PeriodicalId":337873,"journal":{"name":"Proceedings of MILCOM '94","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1994-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129953608","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 : 1994-10-02DOI: 10.1109/MILCOM.1994.474006
T. Gulliver, E. Felstead, R. Ezers, J. Wight
Frequency hopping (FH) spread spectrum is used in communications systems to provide protection against jamming. With fast FH, there are L/spl ges/1 hops per data symbol transmitted. In the presence of severe interference, additional protection can be obtained by processing the LM values obtained from the demodulator. This processing is termed diversity combining. Many powerful and robust types of diversity combining have been developed to reduce the effects of a large jamming signal on some of the L hops. In this paper, a survey of combining methods is presented. Simulation performance results are given for severe noise and multitone jamming (SJR=0.0 dB). It is found that bit error rates as high as 0.4 can be reduced to <0.1 for L<10 using any of several diversity combining methods.<>
{"title":"A unified approach to time diversity combining for fast frequency hopped NCMFSK-anti-jam processing","authors":"T. Gulliver, E. Felstead, R. Ezers, J. Wight","doi":"10.1109/MILCOM.1994.474006","DOIUrl":"https://doi.org/10.1109/MILCOM.1994.474006","url":null,"abstract":"Frequency hopping (FH) spread spectrum is used in communications systems to provide protection against jamming. With fast FH, there are L/spl ges/1 hops per data symbol transmitted. In the presence of severe interference, additional protection can be obtained by processing the LM values obtained from the demodulator. This processing is termed diversity combining. Many powerful and robust types of diversity combining have been developed to reduce the effects of a large jamming signal on some of the L hops. In this paper, a survey of combining methods is presented. Simulation performance results are given for severe noise and multitone jamming (SJR=0.0 dB). It is found that bit error rates as high as 0.4 can be reduced to <0.1 for L<10 using any of several diversity combining methods.<<ETX>>","PeriodicalId":337873,"journal":{"name":"Proceedings of MILCOM '94","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1994-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129154107","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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