Pub Date : 1988-10-23DOI: 10.1109/MILCOM.1988.13485
L. Sadiq, A. Aghvami
The authors evaluate the performance of a hybrid direct-sequence/frequency-hopped spread-spectrum communication system in the presence of partial band interference, multiple-access interference and additive white Gaussian noise. The system uses an MFSK modulator (M>or=2) and a noncoherent demodulator with forward error correction. Several forward-error-control coding schemes have been considered to improve the performance of the system. These schemes either reduce the signal-to-noise ratio required to achieve a desirable bit error rate with fixed number of users, frequency slots, and code rate, or they increase the number of users of the network with the rest of the system parameters fixed. It was also shown that partial band interference substantially degrades the performance of the hybrid multiple-access system.<>
{"title":"Performance of a coded hybrid spread spectrum communication system in the presence of partial band noise and multiple access interference","authors":"L. Sadiq, A. Aghvami","doi":"10.1109/MILCOM.1988.13485","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13485","url":null,"abstract":"The authors evaluate the performance of a hybrid direct-sequence/frequency-hopped spread-spectrum communication system in the presence of partial band interference, multiple-access interference and additive white Gaussian noise. The system uses an MFSK modulator (M>or=2) and a noncoherent demodulator with forward error correction. Several forward-error-control coding schemes have been considered to improve the performance of the system. These schemes either reduce the signal-to-noise ratio required to achieve a desirable bit error rate with fixed number of users, frequency slots, and code rate, or they increase the number of users of the network with the rest of the system parameters fixed. It was also shown that partial band interference substantially degrades the performance of the hybrid multiple-access system.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"27 19 1","pages":"817-821 vol.3"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86630738","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13430
S. Laufer, A. Reichman
The interleaving span of coded frequency-hopped systems is often constrained to be smaller than the decoder memory length, i.e. nonideal interleaving is performed. Analysis of the performance of a hard-decision decoder and an erasure-control decoder of Reed-Solomon codes is presented, both for ideal and nonideal interleaving. The interference consists of worst-case partial-band noise jamming and thermal noise. The frequency hopping system considered uses orthogonal MFSK modulation and noncoherent demodulation with quality bit output based on Viterbi's ratio-threshold technique. Optimization of the ratio-threshold and the erasure-control parameters is performed in worst-case partial-band jamming, and the resulting performance for several interleaver spans is presented.<>
{"title":"Analysis of Reed-Solomon coded frequency-hopping systems with non ideal interleaving in worst case partial band jamming","authors":"S. Laufer, A. Reichman","doi":"10.1109/MILCOM.1988.13430","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13430","url":null,"abstract":"The interleaving span of coded frequency-hopped systems is often constrained to be smaller than the decoder memory length, i.e. nonideal interleaving is performed. Analysis of the performance of a hard-decision decoder and an erasure-control decoder of Reed-Solomon codes is presented, both for ideal and nonideal interleaving. The interference consists of worst-case partial-band noise jamming and thermal noise. The frequency hopping system considered uses orthogonal MFSK modulation and noncoherent demodulation with quality bit output based on Viterbi's ratio-threshold technique. Optimization of the ratio-threshold and the erasure-control parameters is performed in worst-case partial-band jamming, and the resulting performance for several interleaver spans is presented.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"45 1","pages":"449-453 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88103772","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13487
G. Stuber
The author presents a throughput analysis of slotted direct-sequence spread-spectrum multiple-access networks operating in the presence of background noise. The network consists of an infinite population of transceivers and the traffic is characterized by Poisson arrivals. The packets are protected by using forward-error correction coding along with hard decision decoding. The dependency of the optimal processing gain and code rate on system parameters is examined in detail. It is shown that, for a specified traffic intensity and signal-to-noise ratio, there is an optimal code rate and processing gain that maximizes the throughput. It is concluded that many important properties were revealed that are, quite likely, general characteristics of CDMA networks.<>
{"title":"Performance analysis of slotted direct-sequence spread-spectrum multiple-access networks","authors":"G. Stuber","doi":"10.1109/MILCOM.1988.13487","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13487","url":null,"abstract":"The author presents a throughput analysis of slotted direct-sequence spread-spectrum multiple-access networks operating in the presence of background noise. The network consists of an infinite population of transceivers and the traffic is characterized by Poisson arrivals. The packets are protected by using forward-error correction coding along with hard decision decoding. The dependency of the optimal processing gain and code rate on system parameters is examined in detail. It is shown that, for a specified traffic intensity and signal-to-noise ratio, there is an optimal code rate and processing gain that maximizes the throughput. It is concluded that many important properties were revealed that are, quite likely, general characteristics of CDMA networks.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"116 1","pages":"833-837 vol.3"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87961916","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13471
H. Cronson, S. H. Talbot
The authors discuss the development cycle for EHF SATCOM military terminals based on system requirements that include technical and programmatic uncertainties; generic technical problems; specific technology alternatives for antennas, solid-state amplifiers, EHF/SHF analog circuits, digital circuits, fiber optics, and superconductivity; and technology transition approaches. It is concluded that multiple advanced-development-model terminals and major subsystems should be developed simultaneously to minimize risk, foster competition, expedite demonstration of novel technologies, reduce costs, and reduce schedule delay.<>
{"title":"Challenges of advanced EHF SATCOM terminal development","authors":"H. Cronson, S. H. Talbot","doi":"10.1109/MILCOM.1988.13471","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13471","url":null,"abstract":"The authors discuss the development cycle for EHF SATCOM military terminals based on system requirements that include technical and programmatic uncertainties; generic technical problems; specific technology alternatives for antennas, solid-state amplifiers, EHF/SHF analog circuits, digital circuits, fiber optics, and superconductivity; and technology transition approaches. It is concluded that multiple advanced-development-model terminals and major subsystems should be developed simultaneously to minimize risk, foster competition, expedite demonstration of novel technologies, reduce costs, and reduce schedule delay.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"16 1","pages":"727-730 vol.3"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90491601","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13438
N. Shacham
The unique features of a multisatellite network, which distinguish it from ordinary terrestrial networks, are the large propagation delay on the links, the constant changes in the network topology, and additional constraints such as limitation on power consumption. It is noted that ordinary protocols, which are designed to operate in stable, benign environments, will perform poorly under the dynamic conditions of multisatellite network. The author analyzes the limitations to existing protocols and describes protocols, such as routing, topology control, and reliable transport, that are suitable for multisatellite networks.<>
{"title":"Protocols for multi-satellite networks","authors":"N. Shacham","doi":"10.1109/MILCOM.1988.13438","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13438","url":null,"abstract":"The unique features of a multisatellite network, which distinguish it from ordinary terrestrial networks, are the large propagation delay on the links, the constant changes in the network topology, and additional constraints such as limitation on power consumption. It is noted that ordinary protocols, which are designed to operate in stable, benign environments, will perform poorly under the dynamic conditions of multisatellite network. The author analyzes the limitations to existing protocols and describes protocols, such as routing, topology control, and reliable transport, that are suitable for multisatellite networks.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"20 51","pages":"501-505 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91506014","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13441
R. Boyd, S. Adams, M. Spellman, L. V. Lucas
The authors address the physical layer of a survivable communication network built around a space segment. The physical layer consists of satellites and ground stations, as well as the cross and up/down links between them. The proliferated-network approach to survivability is considered. Survivability is obtained by adapting to losses rather than by preventing them. It is noted that while power and cost constraints prohibit extensive electronic communication countermeasures on individual links, judicious choices of modulation, coding and antenna patterns provide some level of protection from less determined interferers. Issues of antenna selection, signal processing, and physical-connection activation are examined. It is concluded that a network of proliferated, low-earth orbit satellites can provide a viable approach to realizing robust, cost-effective communications.<>
{"title":"Survivable space networks: the physical layer","authors":"R. Boyd, S. Adams, M. Spellman, L. V. Lucas","doi":"10.1109/MILCOM.1988.13441","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13441","url":null,"abstract":"The authors address the physical layer of a survivable communication network built around a space segment. The physical layer consists of satellites and ground stations, as well as the cross and up/down links between them. The proliferated-network approach to survivability is considered. Survivability is obtained by adapting to losses rather than by preventing them. It is noted that while power and cost constraints prohibit extensive electronic communication countermeasures on individual links, judicious choices of modulation, coding and antenna patterns provide some level of protection from less determined interferers. Issues of antenna selection, signal processing, and physical-connection activation are examined. It is concluded that a network of proliferated, low-earth orbit satellites can provide a viable approach to realizing robust, cost-effective communications.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"50 1","pages":"521-526 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90840332","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13467
R. Borchardt, T. Ha
The authors investigate the throughput of unslotted ALOHA with power-capture capability. Two types of capture effects are considered, namely created capture and natural capture. The capture probability of a tagged packet is a function of the maximum number of interfering packets that form a stochastic process during the transmission time of a tagged packet. The distribution of the maximum number of interfacing packets can be found from a set of appropriate binary numbers. Four cases are analyzed: ALOHA with two random power levels, ALOHA in a uniform Rayleigh fading channel, ALOHA with two random power levels in a uniform Rayleigh fading channel, and ALOHA-CDMA in a uniform Rayleigh fading channel.<>
{"title":"Power capture ALOHA","authors":"R. Borchardt, T. Ha","doi":"10.1109/MILCOM.1988.13467","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13467","url":null,"abstract":"The authors investigate the throughput of unslotted ALOHA with power-capture capability. Two types of capture effects are considered, namely created capture and natural capture. The capture probability of a tagged packet is a function of the maximum number of interfering packets that form a stochastic process during the transmission time of a tagged packet. The distribution of the maximum number of interfacing packets can be found from a set of appropriate binary numbers. Four cases are analyzed: ALOHA with two random power levels, ALOHA in a uniform Rayleigh fading channel, ALOHA with two random power levels in a uniform Rayleigh fading channel, and ALOHA-CDMA in a uniform Rayleigh fading channel.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"42 1","pages":"703-707 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90199221","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13367
D.R. Smith, R. A. Orr
The authors provide engineering criteria for the application of reduced-rate coding (RRC) and speech-interpolation (SI) techniques to the defense communications system (DCS). These two technologies each offer a 2:1 compression of bit rate or bandwidth for transmission of voice channels. Compression via speech interpolation is achieved through the removal of the gaps and pauses which occur naturally in speech, while reduced-rate coding uses 32 kb/s coding instead of conventional 64 kb/s coding. A description of the performance in these two technologies is given and the application criteria for RRC/SI use in the DCS are developed.<>
{"title":"Application of reduced rate coding and speech interpolation to the DCS","authors":"D.R. Smith, R. A. Orr","doi":"10.1109/MILCOM.1988.13367","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13367","url":null,"abstract":"The authors provide engineering criteria for the application of reduced-rate coding (RRC) and speech-interpolation (SI) techniques to the defense communications system (DCS). These two technologies each offer a 2:1 compression of bit rate or bandwidth for transmission of voice channels. Compression via speech interpolation is achieved through the removal of the gaps and pauses which occur naturally in speech, while reduced-rate coding uses 32 kb/s coding instead of conventional 64 kb/s coding. A description of the performance in these two technologies is given and the application criteria for RRC/SI use in the DCS are developed.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"189 1","pages":"51-56 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77372091","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13490
C. Golden
The need for a more autonomous support system for satellites when the conventional C/sup 2/ infrastructure is not available is discussed. The current level of autonomy is assessed, and the use of software techniques associated with artificial intelligence (AI) research to meet autonomy requirements is examined. Attention is given to such AI-based approaches as (1) model-based reasoning which uses causal models of the system and its environment to reason about situations, and (2) natural-language programming.<>
{"title":"The why and how of satellite autonomy","authors":"C. Golden","doi":"10.1109/MILCOM.1988.13490","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13490","url":null,"abstract":"The need for a more autonomous support system for satellites when the conventional C/sup 2/ infrastructure is not available is discussed. The current level of autonomy is assessed, and the use of software techniques associated with artificial intelligence (AI) research to meet autonomy requirements is examined. Attention is given to such AI-based approaches as (1) model-based reasoning which uses causal models of the system and its environment to reason about situations, and (2) natural-language programming.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"188 1","pages":"853-857 vol.3"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72772431","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13440
R.P. Kosowsky, I. Jacobs, K. Gilhousen
A new link-layer communications protocol is presented for a packet switched, low-altitude, multiple-satellite network. The adaptive receive node scheduling (ARNS) protocol accommodates large numbers of low-cost satellites in nongeosynchronous orbits where global synchronization is not possible, as well as numerous terminals. Theoretical analysis and computer simulation of the protocol show that a satellite operating at a throughput of 1 Mb/s and maintaining simultaneous crosslinks with four neighboring satellites realize an average delay per packet of 11 ms. The 95% of delay figure is 22 ms.<>
{"title":"ARNS: a new link layer protocol","authors":"R.P. Kosowsky, I. Jacobs, K. Gilhousen","doi":"10.1109/MILCOM.1988.13440","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13440","url":null,"abstract":"A new link-layer communications protocol is presented for a packet switched, low-altitude, multiple-satellite network. The adaptive receive node scheduling (ARNS) protocol accommodates large numbers of low-cost satellites in nongeosynchronous orbits where global synchronization is not possible, as well as numerous terminals. Theoretical analysis and computer simulation of the protocol show that a satellite operating at a throughput of 1 Mb/s and maintaining simultaneous crosslinks with four neighboring satellites realize an average delay per packet of 11 ms. The 95% of delay figure is 22 ms.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"35 1","pages":"515-519 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87508711","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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