Pub Date : 1984-12-01DOI: 10.1109/MILCOM.1984.4794851
Y. T. Su, C. Chie
The potential advantages of using CCD or other matched filtering devices to achieve rapid pseudonoise (PN) signal acquisition is well known. This paper presents performance analysis of two major algorithms using CCD PN matched filters. It is shown that in a large uncertainty range and low chip signal-to-noise ratio (Ec/No) environment, parallel-serial search is superior to serial-parallel search though this advantage dwindles as Ec/No increases. On the other hand, parallel search is a more favorable choice if the uncertainty range is small.
{"title":"Rapid Pseudonoise Signal Acquisition Algorithms Employing Charge-Coupled Device Matched Filters","authors":"Y. T. Su, C. Chie","doi":"10.1109/MILCOM.1984.4794851","DOIUrl":"https://doi.org/10.1109/MILCOM.1984.4794851","url":null,"abstract":"The potential advantages of using CCD or other matched filtering devices to achieve rapid pseudonoise (PN) signal acquisition is well known. This paper presents performance analysis of two major algorithms using CCD PN matched filters. It is shown that in a large uncertainty range and low chip signal-to-noise ratio (Ec/No) environment, parallel-serial search is superior to serial-parallel search though this advantage dwindles as Ec/No increases. On the other hand, parallel search is a more favorable choice if the uncertainty range is small.","PeriodicalId":375763,"journal":{"name":"MILCOM 1984 - IEEE Military Communications Conference","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1984-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115290425","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 : 1984-12-01DOI: 10.1109/MILCOM.1984.4795004
J. Modestino, G. Bechtel
Considerable work has been done in developing efficient error-control coding schemes for the ideal optical PPM channel under self-noise limited conditions in the absence of either dark current or background thermal noise effects. In this work we consider corresponding coding options for the degraded PPM channel operating in the presence of dark current but no thermal noise. Coding options studied include use of non-binary Reed-Solomon (RS) codes operating in an errors-erasures mode as well as non-binary convolutional codes utilizing Viterbi maximum likelihood (ML) decoding. We also describe the performance and complexity of a novel concatenated coding scheme employing non-binary convolutional inner codes and RS outer codes. The results provide a first step in providing an assessment of coding options for the more general optical PPM channel which includes background thermal noise as well as dark current.
{"title":"Coding Options for the Degraded Optical PPM Channel","authors":"J. Modestino, G. Bechtel","doi":"10.1109/MILCOM.1984.4795004","DOIUrl":"https://doi.org/10.1109/MILCOM.1984.4795004","url":null,"abstract":"Considerable work has been done in developing efficient error-control coding schemes for the ideal optical PPM channel under self-noise limited conditions in the absence of either dark current or background thermal noise effects. In this work we consider corresponding coding options for the degraded PPM channel operating in the presence of dark current but no thermal noise. Coding options studied include use of non-binary Reed-Solomon (RS) codes operating in an errors-erasures mode as well as non-binary convolutional codes utilizing Viterbi maximum likelihood (ML) decoding. We also describe the performance and complexity of a novel concatenated coding scheme employing non-binary convolutional inner codes and RS outer codes. The results provide a first step in providing an assessment of coding options for the more general optical PPM channel which includes background thermal noise as well as dark current.","PeriodicalId":375763,"journal":{"name":"MILCOM 1984 - IEEE Military Communications Conference","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1984-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134206293","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 : 1984-12-01DOI: 10.1109/MILCOM.1984.4794857
E. Swartzlander, Z. Stroll
This paper describes recent progress in the implementation of a high speed Fast Fourier Transform (FFT) processor with state-of-the-art VLSI circuits. Initial efforts have produced FFT and inverse FFT processors that operate at data rates of up to 40 MHz (complex). The current implementation computes transforms of up to 16,384 points in length by means of the McClellan and Purdy radix 4 pipeline FFT algorithm. The arithmetic is performed by single chip 22 bit floating point adders and multipliers, while the interstage reordering is performed by delay commutators implemented with semi-custom VLSI. This paper explains the pipeline FFT implementation and focuses attention on our current activity which involves developing a fixed point arithmetic version using CMOS multipliers and adders to reduce the power consumption.
{"title":"High Speed FFT Processor Implementation","authors":"E. Swartzlander, Z. Stroll","doi":"10.1109/MILCOM.1984.4794857","DOIUrl":"https://doi.org/10.1109/MILCOM.1984.4794857","url":null,"abstract":"This paper describes recent progress in the implementation of a high speed Fast Fourier Transform (FFT) processor with state-of-the-art VLSI circuits. Initial efforts have produced FFT and inverse FFT processors that operate at data rates of up to 40 MHz (complex). The current implementation computes transforms of up to 16,384 points in length by means of the McClellan and Purdy radix 4 pipeline FFT algorithm. The arithmetic is performed by single chip 22 bit floating point adders and multipliers, while the interstage reordering is performed by delay commutators implemented with semi-custom VLSI. This paper explains the pipeline FFT implementation and focuses attention on our current activity which involves developing a fixed point arithmetic version using CMOS multipliers and adders to reduce the power consumption.","PeriodicalId":375763,"journal":{"name":"MILCOM 1984 - IEEE Military Communications Conference","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1984-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131695790","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 : 1984-12-01DOI: 10.1109/MILCOM.1984.4794903
B. Aazhang, H. Poor
Performance of digital linear correlation receivers is studied in a multi-user environment. There are assumed to be two types of sources interfering with data transmission; multiple-access interference, and additive channel noise, which is attributed to non-Gaussian sources in the environment. The contribution of multi-user interference is examined by considering K users transmitting over a channel using the binary PSK direct-sequence SSMA technique. However, the effects of the non-Gaussian channel in such systems is studied by modeling the samples of noise after front-end filtering. To compare the significance of the two interferers, the integration of the characteristic function method is used to compute the average bit error probability. The results indicate that in most of the noise models considered, the degradation in error probability due to the non-Gaussian nature of the noise is more than that due to the interference of extra users sharing the channel.
{"title":"Nongaussian Effects in DS/SSMA Communications","authors":"B. Aazhang, H. Poor","doi":"10.1109/MILCOM.1984.4794903","DOIUrl":"https://doi.org/10.1109/MILCOM.1984.4794903","url":null,"abstract":"Performance of digital linear correlation receivers is studied in a multi-user environment. There are assumed to be two types of sources interfering with data transmission; multiple-access interference, and additive channel noise, which is attributed to non-Gaussian sources in the environment. The contribution of multi-user interference is examined by considering K users transmitting over a channel using the binary PSK direct-sequence SSMA technique. However, the effects of the non-Gaussian channel in such systems is studied by modeling the samples of noise after front-end filtering. To compare the significance of the two interferers, the integration of the characteristic function method is used to compute the average bit error probability. The results indicate that in most of the noise models considered, the degradation in error probability due to the non-Gaussian nature of the noise is more than that due to the interference of extra users sharing the channel.","PeriodicalId":375763,"journal":{"name":"MILCOM 1984 - IEEE Military Communications Conference","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1984-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128212979","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 : 1984-12-01DOI: 10.1109/MILCOM.1984.4794846
Y. T. Su, C. Weber
The variable dwell time (VDT) acquisition algorithm has been proposed to reduce the mean acquisition time [1,2] of a PN waveform. Previous analyses pertaining to VDT systems have used either approximation methods [1-3] or simulations [4] to evaluate related system performance parameters, namely, PD, PFA and n, the mean dwell time per cell. We present two related algorithms to compute these parameters. Exact results are obtained by these algorithms. Furthermore, PFA and n can be evaluated more efficiently.
{"title":"On the Performance Evaluation of Variable-Dwell Time PN Acquisition Systems","authors":"Y. T. Su, C. Weber","doi":"10.1109/MILCOM.1984.4794846","DOIUrl":"https://doi.org/10.1109/MILCOM.1984.4794846","url":null,"abstract":"The variable dwell time (VDT) acquisition algorithm has been proposed to reduce the mean acquisition time [1,2] of a PN waveform. Previous analyses pertaining to VDT systems have used either approximation methods [1-3] or simulations [4] to evaluate related system performance parameters, namely, PD, PFA and n, the mean dwell time per cell. We present two related algorithms to compute these parameters. Exact results are obtained by these algorithms. Furthermore, PFA and n can be evaluated more efficiently.","PeriodicalId":375763,"journal":{"name":"MILCOM 1984 - IEEE Military Communications Conference","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1984-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127714728","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 : 1984-12-01DOI: 10.1109/MILCOM.1984.4795020
S. Su, V. Li
A performance model of a multihop Code Division Multiple Access(CDMA) Spread Spectrum Network is presented. Time is divided into slots and the network nodes are synchronized such that fixed length messages will only be sent at the beginning of slots. The message generation processes at the nodes are assumed to be independent Bernoulli processes. A node may transmit or receive in a slot, but not both. Each transmission is preceded by a preamble used by the receiver for acquisition purposes. Both the preamble and the message are encoded in the PN code which is unique to the particular receiver. Steady state results for the throughput versus offered traffic, and the delay versus throughput were obtained. This model will be illustrated by examples.
{"title":"Performance Analysis of a Slotted Code Division Multiple Access(CDMA) Network","authors":"S. Su, V. Li","doi":"10.1109/MILCOM.1984.4795020","DOIUrl":"https://doi.org/10.1109/MILCOM.1984.4795020","url":null,"abstract":"A performance model of a multihop Code Division Multiple Access(CDMA) Spread Spectrum Network is presented. Time is divided into slots and the network nodes are synchronized such that fixed length messages will only be sent at the beginning of slots. The message generation processes at the nodes are assumed to be independent Bernoulli processes. A node may transmit or receive in a slot, but not both. Each transmission is preceded by a preamble used by the receiver for acquisition purposes. Both the preamble and the message are encoded in the PN code which is unique to the particular receiver. Steady state results for the throughput versus offered traffic, and the delay versus throughput were obtained. This model will be illustrated by examples.","PeriodicalId":375763,"journal":{"name":"MILCOM 1984 - IEEE Military Communications Conference","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1984-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114983221","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 : 1984-10-01DOI: 10.1109/MILCOM.1984.4794997
J. Rebman
This paper describes features desirable in commercial satellite earth stations to enhance their use for DOD applications. The introduction is a challenge presented as a "wish list." The challenge is meant to stimulate thinking by the users, the carriers, and the hardware developer/ suppliers. The ultimate objective is to determine what enhancements might be accomplished and develop the specifications necessary to procure these functions within budgets for application to specific C3 missions. The summary section describes an alternate approach to interoperability that can accomplish many of the same goals of a hardware approach but at a reduced cost.
{"title":"The \"Transparent\" Earth Station","authors":"J. Rebman","doi":"10.1109/MILCOM.1984.4794997","DOIUrl":"https://doi.org/10.1109/MILCOM.1984.4794997","url":null,"abstract":"This paper describes features desirable in commercial satellite earth stations to enhance their use for DOD applications. The introduction is a challenge presented as a \"wish list.\" The challenge is meant to stimulate thinking by the users, the carriers, and the hardware developer/ suppliers. The ultimate objective is to determine what enhancements might be accomplished and develop the specifications necessary to procure these functions within budgets for application to specific C3 missions. The summary section describes an alternate approach to interoperability that can accomplish many of the same goals of a hardware approach but at a reduced cost.","PeriodicalId":375763,"journal":{"name":"MILCOM 1984 - IEEE Military Communications Conference","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1984-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117194318","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 : 1984-10-01DOI: 10.1109/MILCOM.1984.4794904
P. Ma, P. McLane
Frequency offsets in the receivea signal can degrade the performance of trequency hopping, multiuser spread spectrum communication systems that use M-Ary FSK modulation. To compensate for this degradation a windowed receiver is used which will allow suppression of adjacent channel interference. It is then necessary to find out how the system performance will change with the variation of window parameters. We present a technique for estimating the symbol error rate for windowed M-Ary reception. Optimum window parameters are found for M-Ary FSK for M = 2, 4 and 8.
{"title":"On Frequency Offsets in Windowed Reception of Frequency Dehopped M-Ary FSK Signals for Multiuser Systems","authors":"P. Ma, P. McLane","doi":"10.1109/MILCOM.1984.4794904","DOIUrl":"https://doi.org/10.1109/MILCOM.1984.4794904","url":null,"abstract":"Frequency offsets in the receivea signal can degrade the performance of trequency hopping, multiuser spread spectrum communication systems that use M-Ary FSK modulation. To compensate for this degradation a windowed receiver is used which will allow suppression of adjacent channel interference. It is then necessary to find out how the system performance will change with the variation of window parameters. We present a technique for estimating the symbol error rate for windowed M-Ary reception. Optimum window parameters are found for M-Ary FSK for M = 2, 4 and 8.","PeriodicalId":375763,"journal":{"name":"MILCOM 1984 - IEEE Military Communications Conference","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1984-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125281874","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 : 1984-10-01DOI: 10.1109/MILCOM.1984.4794886
R. Moynihan
Over the last ten years, the MITRE Corporation has been involved in the life cycle cost (LCC) evaluation of proposed and implemented systems for the AFSATCOM and MILSTAR Programs. In particular, LCC computer models have been created to represent the logistics structure and associated operation and support costs of airborne satellite communications systems. These LCC Models allow for the representation of differing equipment configurations on multiple platform types (both airborne and ground) and for variable platform deployments at bases worldwide. The LCC Models are also flexible enough to analyze differing maintenance concepts, including two versus three-level repair and centralized intermediate maintenance facilities. These LCC Models have been provided to contractors both for their in-house use in conducting LCC analysis and for reporting LCC results to the Government. The prime purposes these LCC Models have served are to: (1) Identify high LCC drivers in both equipment design and support concepts, (2) Serve as a LCC trade-off analysis tool, and (3) Provide a Government-approved and uniform framework for LCC analysis by competing contractors (i.e., avoiding "apples versus oranges" comparisons). Several specific examples of cost savings generated by this LCC analysis are illustrated, including an analysis of AFSATCOM support equipment deployment.
{"title":"Life Cycle Cost Analysis of Satellite Communications Systems","authors":"R. Moynihan","doi":"10.1109/MILCOM.1984.4794886","DOIUrl":"https://doi.org/10.1109/MILCOM.1984.4794886","url":null,"abstract":"Over the last ten years, the MITRE Corporation has been involved in the life cycle cost (LCC) evaluation of proposed and implemented systems for the AFSATCOM and MILSTAR Programs. In particular, LCC computer models have been created to represent the logistics structure and associated operation and support costs of airborne satellite communications systems. These LCC Models allow for the representation of differing equipment configurations on multiple platform types (both airborne and ground) and for variable platform deployments at bases worldwide. The LCC Models are also flexible enough to analyze differing maintenance concepts, including two versus three-level repair and centralized intermediate maintenance facilities. These LCC Models have been provided to contractors both for their in-house use in conducting LCC analysis and for reporting LCC results to the Government. The prime purposes these LCC Models have served are to: (1) Identify high LCC drivers in both equipment design and support concepts, (2) Serve as a LCC trade-off analysis tool, and (3) Provide a Government-approved and uniform framework for LCC analysis by competing contractors (i.e., avoiding \"apples versus oranges\" comparisons). Several specific examples of cost savings generated by this LCC analysis are illustrated, including an analysis of AFSATCOM support equipment deployment.","PeriodicalId":375763,"journal":{"name":"MILCOM 1984 - IEEE Military Communications Conference","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1984-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122326712","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 : 1984-10-01DOI: 10.1109/MILCOM.1984.4795005
W. Marshall
Methods of detection and synchronization in a highly efficient direct detection optical communication system are reported. Results of measurements on this moderate-rate demonstration system capable of transmitting 2.5 bits/detected photon in low background situations indicate that symbol slot synchronization is not a problem, and that a simple symbol detection scheme is adequate for this situation. This system is a candidate for interplanetary optical communications.
{"title":"Detection and Symbol Synchronization for Multiple-Bit Per Photon Optical Communications","authors":"W. Marshall","doi":"10.1109/MILCOM.1984.4795005","DOIUrl":"https://doi.org/10.1109/MILCOM.1984.4795005","url":null,"abstract":"Methods of detection and synchronization in a highly efficient direct detection optical communication system are reported. Results of measurements on this moderate-rate demonstration system capable of transmitting 2.5 bits/detected photon in low background situations indicate that symbol slot synchronization is not a problem, and that a simple symbol detection scheme is adequate for this situation. This system is a candidate for interplanetary optical communications.","PeriodicalId":375763,"journal":{"name":"MILCOM 1984 - IEEE Military Communications Conference","volume":"223 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1984-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122883336","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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