Pub Date : 1982-10-01DOI: 10.1109/MILCOM.1982.4805967
R. Gorur, A. Payzin, H. Oranc
A new spread spectrum technique called Multi-Subchannel Spread Spectrum Modulation (MSCSSM) is proposed. The system basically consists of the superposition of M different direct sequence (DS) spread spectrum systems having different carrier frequencies. Main feature of the proposed system is that the spreading bandwidth and hence the processing gain can be increased, without a need for increasing the spreading code sequence rate, by increasing the number of subchannels used. Bit error performance of MSCSSM system in the presence of additive white Gaussian noise and interference from other similar transmitters or CW tone jamming is analysed. For both of the above mentioned types of interference, the MSCSSM system is shown to have a performance advantage over a DS spread spectrum system utilizing the same spreading bandwidth to data bit rate ratio.
{"title":"Multi-Subchannel Spread Spectrum Modulation","authors":"R. Gorur, A. Payzin, H. Oranc","doi":"10.1109/MILCOM.1982.4805967","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805967","url":null,"abstract":"A new spread spectrum technique called Multi-Subchannel Spread Spectrum Modulation (MSCSSM) is proposed. The system basically consists of the superposition of M different direct sequence (DS) spread spectrum systems having different carrier frequencies. Main feature of the proposed system is that the spreading bandwidth and hence the processing gain can be increased, without a need for increasing the spreading code sequence rate, by increasing the number of subchannels used. Bit error performance of MSCSSM system in the presence of additive white Gaussian noise and interference from other similar transmitters or CW tone jamming is analysed. For both of the above mentioned types of interference, the MSCSSM system is shown to have a performance advantage over a DS spread spectrum system utilizing the same spreading bandwidth to data bit rate ratio.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"335 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122917579","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805971
S. Crozier, K. Tiedemann, R. Lyons, J. Lodge
Performance is presented for a non-real-time (NRT) software coherent binary phase shift keyed (BPSK) receiver using both simulated and recorded HF signals at a bit rate of 2.4 kbps. The receiver consists of: (1) an adaptive matched filter, (2) a maximum likelihood sequence estimator (MLSE) incorporating a modified Viterbi algorithm (MVA), (3) a maximum likelihood (in nature) channel estimator (MLCE) algorithm based on a discrete multipath channel model. For all simulated fixed and time-varying channels, performance is presented in terms of bit error rate (BER) versus average Eb/No. Examples of channel acquisition and tracking are also presented. For the recorded HF signals, performance is presented in terms of BER and availability measures. The implementation of a 2.4 kbps modem suitable for military HF communications applications based on maximum likelihood principles is given preliminary consideration.
{"title":"An Adaptive Maximum Likelihood Sequence Estimation Technique for Wideband HF Communications","authors":"S. Crozier, K. Tiedemann, R. Lyons, J. Lodge","doi":"10.1109/MILCOM.1982.4805971","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805971","url":null,"abstract":"Performance is presented for a non-real-time (NRT) software coherent binary phase shift keyed (BPSK) receiver using both simulated and recorded HF signals at a bit rate of 2.4 kbps. The receiver consists of: (1) an adaptive matched filter, (2) a maximum likelihood sequence estimator (MLSE) incorporating a modified Viterbi algorithm (MVA), (3) a maximum likelihood (in nature) channel estimator (MLCE) algorithm based on a discrete multipath channel model. For all simulated fixed and time-varying channels, performance is presented in terms of bit error rate (BER) versus average Eb/No. Examples of channel acquisition and tracking are also presented. For the recorded HF signals, performance is presented in terms of BER and availability measures. The implementation of a 2.4 kbps modem suitable for military HF communications applications based on maximum likelihood principles is given preliminary consideration.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129892287","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4806011
M. S. Frankel
Two testbeds have been established to transfer emerging technology from the research community to the military thereby providing a basis for developing new military concepts for force effectiveness and survivability. Although still emerging, these technologies are now being presented to the user to make it possible to investigate (today) command, control and communications (C3) concepts that might otherwise not be considered for another decade. The technologies being transferred include: automated tactical reporting systems, advanced packet-switched communication, automated man-machine interfaces, communication network and internetwork environments, automated display and analysis of data, and techniques for automatically disseminating information into redundant/distributed data bases. Expectations are that the testbeds will ultimately lead to the definition of military distributed C3 architectures that will permit a commander to execute his mission in the "battlefield of the future" more effectively.
{"title":"Advanced Technology Testbeds for Distributed, Survivable Command, Control and Communications (C3)","authors":"M. S. Frankel","doi":"10.1109/MILCOM.1982.4806011","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4806011","url":null,"abstract":"Two testbeds have been established to transfer emerging technology from the research community to the military thereby providing a basis for developing new military concepts for force effectiveness and survivability. Although still emerging, these technologies are now being presented to the user to make it possible to investigate (today) command, control and communications (C3) concepts that might otherwise not be considered for another decade. The technologies being transferred include: automated tactical reporting systems, advanced packet-switched communication, automated man-machine interfaces, communication network and internetwork environments, automated display and analysis of data, and techniques for automatically disseminating information into redundant/distributed data bases. Expectations are that the testbeds will ultimately lead to the definition of military distributed C3 architectures that will permit a commander to execute his mission in the \"battlefield of the future\" more effectively.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114330237","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805898
N. Krasner
In this paper structures are developed for maximum likelihood estimation of carrier phase and symbol phase for quadriphase modulated signals. These structures differ from those previously presented in that they are recursive and are practical to implement without resorting to approximations. Extensions to cases of filtered and correlated type signals and other signal formats are indicated.
{"title":"Maximum Likelihood Parameter Estimation for LPI Signals","authors":"N. Krasner","doi":"10.1109/MILCOM.1982.4805898","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805898","url":null,"abstract":"In this paper structures are developed for maximum likelihood estimation of carrier phase and symbol phase for quadriphase modulated signals. These structures differ from those previously presented in that they are recursive and are practical to implement without resorting to approximations. Extensions to cases of filtered and correlated type signals and other signal formats are indicated.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"264 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124297965","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805991
C. Hackett
A recursive technique is presented that achieves real-time implementation of the Signal Separator which is an algorithm that can be used with antenna arrays to provide each incident signal at a good output signal-to-interference ratio without having any a priori knowledge of the incident signals or their directions-of-arrival. Simulation results confirm performance previously predicted analytically.
{"title":"Real-Time Implementation of the Signal Separator","authors":"C. Hackett","doi":"10.1109/MILCOM.1982.4805991","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805991","url":null,"abstract":"A recursive technique is presented that achieves real-time implementation of the Signal Separator which is an algorithm that can be used with antenna arrays to provide each incident signal at a good output signal-to-interference ratio without having any a priori knowledge of the incident signals or their directions-of-arrival. Simulation results confirm performance previously predicted analytically.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134133423","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805986
Ernest T. Tsui, R. Ibaraki
Transmitted signal spectrum spreading is used to enhance multipath diversity performance. An adaptive DPSK spread spectrum multiple access receiver structure is presented for which optimal demodulation is obtained in slowly time-varying complex Gaussian scatter/multipath channels under convergence of the adaptive algorithm. The receiver performs a cross-correlation function equalization of a multipath degraded spread spectrum signal using a Stochastic Approximation technique. A potential of coherenit maximal-ratio multipath combining performance can be obtained under general slowly varying channel conditions.
{"title":"An Adaptive Spread Spectrum Receiver for Multipath/Scatter Channels","authors":"Ernest T. Tsui, R. Ibaraki","doi":"10.1109/MILCOM.1982.4805986","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805986","url":null,"abstract":"Transmitted signal spectrum spreading is used to enhance multipath diversity performance. An adaptive DPSK spread spectrum multiple access receiver structure is presented for which optimal demodulation is obtained in slowly time-varying complex Gaussian scatter/multipath channels under convergence of the adaptive algorithm. The receiver performs a cross-correlation function equalization of a multipath degraded spread spectrum signal using a Stochastic Approximation technique. A potential of coherenit maximal-ratio multipath combining performance can be obtained under general slowly varying channel conditions.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"283 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131599876","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805897
A. Polydoros, C. Weber
A variety of receivers which can be used to detect the presence of a wideband (spread) signal in additive white Gaussian noise (AWGN) is explored. The optimality of these receivers is founded upon the knowledge (or lack thereof) of certain key signal parameters. Suboptimal receivers are suggested based upon the removal of knowledge of some of these parameters.
{"title":"Optimal Detection Considerations for Low Probability of Intercept","authors":"A. Polydoros, C. Weber","doi":"10.1109/MILCOM.1982.4805897","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805897","url":null,"abstract":"A variety of receivers which can be used to detect the presence of a wideband (spread) signal in additive white Gaussian noise (AWGN) is explored. The optimality of these receivers is founded upon the knowledge (or lack thereof) of certain key signal parameters. Suboptimal receivers are suggested based upon the removal of knowledge of some of these parameters.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"424 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115594652","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805976
J. Oetting
This paper describes a study of the physical limitations of adaptive antenna arrays using analytical methods. It is shown how the antenna pattern of an N-element array can be calculated from the complex array weights. The available degrees of freedom of the array can be used to null up to N-1 jammers while maintaining gain in the direction of the desired signal. Alternatively, some degrees of freedom can be used to specify other properties of the antenna pattern. As an example, the antenna pattern of a four element two-dimensional array with large, nonuniform element spacing is calculated for the case of three jammers and a desired signal and shown to be superior to the pattern obtained with uniform spacing. It is then shown how further improvements can be obtained by using some of the available degrees of freedom to constrain the first derivative of the pattern in the vicinity of the desired signal. This method produces a "maximally flat" antenna response and eliminates some of the adverse effects of grating lobes. Finally, some other applications of this methodology are mentioned.
{"title":"An Analytical Study of Nonuniformly-Spaced Two Dimensional Adaptive Antenna Arrays","authors":"J. Oetting","doi":"10.1109/MILCOM.1982.4805976","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805976","url":null,"abstract":"This paper describes a study of the physical limitations of adaptive antenna arrays using analytical methods. It is shown how the antenna pattern of an N-element array can be calculated from the complex array weights. The available degrees of freedom of the array can be used to null up to N-1 jammers while maintaining gain in the direction of the desired signal. Alternatively, some degrees of freedom can be used to specify other properties of the antenna pattern. As an example, the antenna pattern of a four element two-dimensional array with large, nonuniform element spacing is calculated for the case of three jammers and a desired signal and shown to be superior to the pattern obtained with uniform spacing. It is then shown how further improvements can be obtained by using some of the available degrees of freedom to constrain the first derivative of the pattern in the vicinity of the desired signal. This method produces a \"maximally flat\" antenna response and eliminates some of the adverse effects of grating lobes. Finally, some other applications of this methodology are mentioned.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115896312","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805926
Warren Tan, Paul Meng, Al Hadad
Standard link protocols have been designed for typical long term bit error rates. A degraded line results in service interruption, requiring end-to-end coordination to effect manual recovery. The minimum throughput could be maintained for exchanging the vital housekeeping and link maintenance information by use of an automatic line recovery scheme. An adaptive data link control protocol is designed for this purpose. As a key feature, the real-time throughput monitoring is performed by correlating several variable parameters, such as: block size, transmission speed, overhead ratio, etc.. Within this paper, the adaptive protocol operational procedure is described in great detail using the ADA design language. Analysis for justifying protocol performance is also provided.
{"title":"Adaptive Protocol for Worsening Communication Line Conditions","authors":"Warren Tan, Paul Meng, Al Hadad","doi":"10.1109/MILCOM.1982.4805926","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805926","url":null,"abstract":"Standard link protocols have been designed for typical long term bit error rates. A degraded line results in service interruption, requiring end-to-end coordination to effect manual recovery. The minimum throughput could be maintained for exchanging the vital housekeeping and link maintenance information by use of an automatic line recovery scheme. An adaptive data link control protocol is designed for this purpose. As a key feature, the real-time throughput monitoring is performed by correlating several variable parameters, such as: block size, transmission speed, overhead ratio, etc.. Within this paper, the adaptive protocol operational procedure is described in great detail using the ADA design language. Analysis for justifying protocol performance is also provided.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"362 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115944166","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805985
F. Garber, M. Pursley
This paper is concerned with the performance of frequency-hopped spread-spectrum multiple-access communications in a fading environment. The data is transmitted on the carrier using differential phase-shift keying with multiple data bits per hop (i.e., slow frequency hopping). The frequency hopping and dehopping are noncoherent. Frequency-selective fading channels are considered for systems with various data pulse waveforms and channel delay power-density spectra. Analytical results for the average probability of error are presented, and numerical examples of the most interesting cases are given.
{"title":"Effects of Frequency-Selective Fading on Slow-Frequency-Hopped DPSK Spread-Spectrum Multiple-Access Communications","authors":"F. Garber, M. Pursley","doi":"10.1109/MILCOM.1982.4805985","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805985","url":null,"abstract":"This paper is concerned with the performance of frequency-hopped spread-spectrum multiple-access communications in a fading environment. The data is transmitted on the carrier using differential phase-shift keying with multiple data bits per hop (i.e., slow frequency hopping). The frequency hopping and dehopping are noncoherent. Frequency-selective fading channels are considered for systems with various data pulse waveforms and channel delay power-density spectra. Analytical results for the average probability of error are presented, and numerical examples of the most interesting cases are given.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114843671","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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