Pub Date : 1982-10-01DOI: 10.1109/MILCOM.1982.4805935
S. Glisic
An analysis of error probability for noncoherent demodulation of spread spectrum signals using charge - coupled devices is presented. Average error probability for SSK-DS-SS (Sequence Shift-keying DS-SS), IQ-DS-SS (In Phase + Quadrature DS-SS), IIQ-DS-SS (Improved IQ-DS-SS) and DDIQ-DS-SS (Differential Data IQ-DS-SS) system is derived.
本文分析了电荷耦合器件对扩频信号进行非相干解调时的误差概率。推导了SSK-DS-SS (Sequence shift -key DS-SS)、IQ-DS-SS (In Phase + Quadrature DS-SS)、IIQ-DS-SS (Improved IQ-DS-SS)和DDIQ-DS-SS (Differential Data IQ-DS-SS)系统的平均误差概率。
{"title":"Noncoherent Demodulation of Spread Spectrum Signals using Charge Coupled Devices","authors":"S. Glisic","doi":"10.1109/MILCOM.1982.4805935","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805935","url":null,"abstract":"An analysis of error probability for noncoherent demodulation of spread spectrum signals using charge - coupled devices is presented. Average error probability for SSK-DS-SS (Sequence Shift-keying DS-SS), IQ-DS-SS (In Phase + Quadrature DS-SS), IIQ-DS-SS (Improved IQ-DS-SS) and DDIQ-DS-SS (Differential Data IQ-DS-SS) system is derived.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"32 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":"126513675","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.1982.4805942
T. Seay
Theoretical bounds are given for the number and length of hopping patterns with a guaranteed maximum number of pairwise hits. Constructions for hopping pattern sets which achieve the single hit bounds are given, as well as hopping patterns which guarantee the maximum number of pairwise hits in the presence of time or frequency asynchrony, or both. It is shown that variable rate coding permits "averaging" of the worst case interference compared to fixed rate coding, when the data messages are of varying duration.
{"title":"Hopping Patterns for Bounded Mutual Interference in Frequency Hopping Multiple Access","authors":"T. Seay","doi":"10.1109/MILCOM.1982.4805942","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805942","url":null,"abstract":"Theoretical bounds are given for the number and length of hopping patterns with a guaranteed maximum number of pairwise hits. Constructions for hopping pattern sets which achieve the single hit bounds are given, as well as hopping patterns which guarantee the maximum number of pairwise hits in the presence of time or frequency asynchrony, or both. It is shown that variable rate coding permits \"averaging\" of the worst case interference compared to fixed rate coding, when the data messages are of varying duration.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"35 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":"126602200","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.1982.4805992
E. Ha, D. Chang, B. Forman
The Hughes experimental multiple-element adaptive array antenna system is based on a hybrid implementation of Widrow's LMS algorithm. A microcomputer samples the analog correlator outputs, then computes the new antenna weight settings and updates the quadrature weighting circuitries accordingly. A hard limiter placed in the feedback path prevents permanent capture by the strongest interference. This configuration appears to circumvent the difficulty in nulling against multiple interferences. Laboratory results demonstrate up to 60 dB cancellation of jammers in a few hundred iterations. System performance degrades to about 30 dB suppression for a 12 percent bandwidth jammer.
{"title":"Adaptive Array with Limiter in Feedback Path Preliminary Results","authors":"E. Ha, D. Chang, B. Forman","doi":"10.1109/MILCOM.1982.4805992","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805992","url":null,"abstract":"The Hughes experimental multiple-element adaptive array antenna system is based on a hybrid implementation of Widrow's LMS algorithm. A microcomputer samples the analog correlator outputs, then computes the new antenna weight settings and updates the quadrature weighting circuitries accordingly. A hard limiter placed in the feedback path prevents permanent capture by the strongest interference. This configuration appears to circumvent the difficulty in nulling against multiple interferences. Laboratory results demonstrate up to 60 dB cancellation of jammers in a few hundred iterations. System performance degrades to about 30 dB suppression for a 12 percent bandwidth jammer.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"25 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":"127075717","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.1982.4806014
D. Behrman, W. C. Fifer
The goal of the Low Cost Packet Radio (LPR) Program funded by DARPA, via a contract through CECOM, Contract No. DAAK80-81-C-0213, and being developed by Hazeltine Corporation, is a packet radio unit with low cost, low weight, low volume, low power, and high reliability. The LPR consists of a digitally controlled spread spectrum radio and a microprocessor acting as a packet switch. It is to be used in support of experiments with large packet radio networks. The radio utilizes direct-sequence, spread-spectrum techniques using MSK modulation. A code-changeable, SAW matched filter is employed. It is followed by a decision-directed, SAW fading memory filter to provide synchronization, multipath accumulation, and demodulation reference functions. Two data transmission rates are provided at 100 kbps or 400 kbps. In order to improve the reliability of the network links, a convolutional encoder/sequential decoder with forward-error correction capability at three code rates has been incorporated. To achieve an undetected BER of 10-12, CRC is employed for both encoded and uncoded modes of operation. Besides the RF data link, the LPR provides an input/output data link at either low or high speed. The microprocessor system architecture has been optimized to maximize its bus bandwidth.
{"title":"A Low-Cost Spread-Spectrum Packet Radio","authors":"D. Behrman, W. C. Fifer","doi":"10.1109/MILCOM.1982.4806014","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4806014","url":null,"abstract":"The goal of the Low Cost Packet Radio (LPR) Program funded by DARPA, via a contract through CECOM, Contract No. DAAK80-81-C-0213, and being developed by Hazeltine Corporation, is a packet radio unit with low cost, low weight, low volume, low power, and high reliability. The LPR consists of a digitally controlled spread spectrum radio and a microprocessor acting as a packet switch. It is to be used in support of experiments with large packet radio networks. The radio utilizes direct-sequence, spread-spectrum techniques using MSK modulation. A code-changeable, SAW matched filter is employed. It is followed by a decision-directed, SAW fading memory filter to provide synchronization, multipath accumulation, and demodulation reference functions. Two data transmission rates are provided at 100 kbps or 400 kbps. In order to improve the reliability of the network links, a convolutional encoder/sequential decoder with forward-error correction capability at three code rates has been incorporated. To achieve an undetected BER of 10-12, CRC is employed for both encoded and uncoded modes of operation. Besides the RF data link, the LPR provides an input/output data link at either low or high speed. The microprocessor system architecture has been optimized to maximize its bus bandwidth.","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":"130883787","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.1982.4806005
P. Sass
The Army is currently developing a variety of ground based tactical communications systems intended to support the needs of the soldier on the automated battlefield of the 1990's. These new systems employ wideband digital techniques to support requirements for speed and volume of data transfer, and have turned to spread spectrum for the Anti-jam (AJ) protection required for survivability under the electronic warfare threat anticipated over the next twenty years. This paper surveys the essential technical characteristics of CECOM's current spread spectrum system developments for ground-to-ground communications, explains their historical and technical evolution, and explores the underlying rationale for selection of Frequency Hopping (FH) versus Direct Sequence (DS) spread spectrum techniques in each case. Observations and future directions conclude the paper.
{"title":"Army Spread Spectrum - Evolution or Revolution","authors":"P. Sass","doi":"10.1109/MILCOM.1982.4806005","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4806005","url":null,"abstract":"The Army is currently developing a variety of ground based tactical communications systems intended to support the needs of the soldier on the automated battlefield of the 1990's. These new systems employ wideband digital techniques to support requirements for speed and volume of data transfer, and have turned to spread spectrum for the Anti-jam (AJ) protection required for survivability under the electronic warfare threat anticipated over the next twenty years. This paper surveys the essential technical characteristics of CECOM's current spread spectrum system developments for ground-to-ground communications, explains their historical and technical evolution, and explores the underlying rationale for selection of Frequency Hopping (FH) versus Direct Sequence (DS) spread spectrum techniques in each case. Observations and future directions conclude the paper.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"28 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":"134270216","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.1982.4805906
H. Ochsner
The effect of certain time-variant channels on the performance of a PN spread-spectrum system is analyzed without assuming perfect synchronization of the receiver's PN sequence. The results show that maximizing the power of the despread signal can be markedly suboptimal concerning the signal-to-noise ratio and that even well-known tracking loops may exhibit only moderate performance.
{"title":"Analysis of Pseudo-Noise Spread-Spectrum Communication over Randomly Time-Variant Channels Without Assuming Perfect Synchronization","authors":"H. Ochsner","doi":"10.1109/MILCOM.1982.4805906","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805906","url":null,"abstract":"The effect of certain time-variant channels on the performance of a PN spread-spectrum system is analyzed without assuming perfect synchronization of the receiver's PN sequence. The results show that maximizing the power of the despread signal can be markedly suboptimal concerning the signal-to-noise ratio and that even well-known tracking loops may exhibit only moderate performance.","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":"115572398","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.1982.4806009
P. Major
Measurements have been made of a spread spectrum transmitter as an interference source to conventional receivers. The measurements provide data to permit some validation of models for EMC analysis. This paper discusses one set of results.
{"title":"Spread Spectrum EMC: Measurements and Analysis","authors":"P. Major","doi":"10.1109/MILCOM.1982.4806009","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4806009","url":null,"abstract":"Measurements have been made of a spread spectrum transmitter as an interference source to conventional receivers. The measurements provide data to permit some validation of models for EMC analysis. This paper discusses one set of results.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"82 s56","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120854689","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.1982.4805908
R. McEliece, W. Stark
We take an abstract view of the problem of coding vs. a jammer on a binary symmetric channel, and conclude that either: coding can completely newtralize the jammer, i.e. render him no worse than uniform background noise; or: the best code rate is exactly r = .3790. Here "best" is with respect to channel capacity as a figure of merit. If the channel cutoff rate is used instead, the best rate is .247. We also give some extensions to M-ary channels, M ¿ 2.
{"title":"The Optimal Code Rate vs. a Partial Band Jammer","authors":"R. McEliece, W. Stark","doi":"10.1109/MILCOM.1982.4805908","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805908","url":null,"abstract":"We take an abstract view of the problem of coding vs. a jammer on a binary symmetric channel, and conclude that either: coding can completely newtralize the jammer, i.e. render him no worse than uniform background noise; or: the best code rate is exactly r = .3790. Here \"best\" is with respect to channel capacity as a figure of merit. If the channel cutoff rate is used instead, the best rate is .247. We also give some extensions to M-ary channels, M ¿ 2.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"15 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":"121289152","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.1982.4806021
A. A. Castro
This paper presents and discusses different approaches available to provide uplink protection to high data rate Users of an EHF satellite communication system, by combining temporal spreading gain with the spatial filtering of a spacecraft adaptive nulling antenna. The generalized performance of different nulling approaches is analyzed, as well as the limitations for simultaneously achieving high resolution over large field of view and wide bandwidth, when multiple Users access the satellite.
{"title":"Uplink Antenna Nulling for High Data Rate EHF Satellite Communications","authors":"A. A. Castro","doi":"10.1109/MILCOM.1982.4806021","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4806021","url":null,"abstract":"This paper presents and discusses different approaches available to provide uplink protection to high data rate Users of an EHF satellite communication system, by combining temporal spreading gain with the spatial filtering of a spacecraft adaptive nulling antenna. The generalized performance of different nulling approaches is analyzed, as well as the limitations for simultaneously achieving high resolution over large field of view and wide bandwidth, when multiple Users access the satellite.","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":"116436186","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.1982.4805978
R. Mathis, K. Kaufman
A new algorithm for adaptively steering antenna pattern nulls while maintaining a pattern maximum on a desired signal is described. The derivation is carried out by maximizing an estimate of the signal-power-to-interference-power ratio. The resulting algorithm employs double loops; one set maximizes the desired signal power and the other set minimizes the interference power. The MAXIMIN algorithm does not require detailed knowledge of the received signal. Rather, it requires only that the desired signal plus interference and noise be separated from interference and noise alone. A detailed simulation of a spread-spectrum (FH/PN) modem incorporating the MAXIMIN algorithm has been developed. The simulation incorporates all known hardware effects having a significant impact on the operation of the algorithm such as: differing group delays of critical filters, nonlinear effects in the cross-correlation multipliers, limited bit resolution in A/D and D/A converters, and mutual coupling between the array elements. Excellent performance in terms of convergence speed and final signal-to-noise ratio is obtained over a wide range of interference conditions. This approach appears to be well suited to frequency-hopping modems.
{"title":"Maximin Adaptive Array Algorithm","authors":"R. Mathis, K. Kaufman","doi":"10.1109/MILCOM.1982.4805978","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805978","url":null,"abstract":"A new algorithm for adaptively steering antenna pattern nulls while maintaining a pattern maximum on a desired signal is described. The derivation is carried out by maximizing an estimate of the signal-power-to-interference-power ratio. The resulting algorithm employs double loops; one set maximizes the desired signal power and the other set minimizes the interference power. The MAXIMIN algorithm does not require detailed knowledge of the received signal. Rather, it requires only that the desired signal plus interference and noise be separated from interference and noise alone. A detailed simulation of a spread-spectrum (FH/PN) modem incorporating the MAXIMIN algorithm has been developed. The simulation incorporates all known hardware effects having a significant impact on the operation of the algorithm such as: differing group delays of critical filters, nonlinear effects in the cross-correlation multipliers, limited bit resolution in A/D and D/A converters, and mutual coupling between the array elements. Excellent performance in terms of convergence speed and final signal-to-noise ratio is obtained over a wide range of interference conditions. This approach appears to be well suited to frequency-hopping modems.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"38 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":"123167505","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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