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11-14 Oct. 1992

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Displaying Results 1 - 25 of 240
  • Space based communication network for DoD applications

    Publication Year: 1992, Page(s):565 - 566 vol.2
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (118 KB)

    Summary form only given. To support low-altitude sensor satellites the authors advocate the establishment of a general-purpose space based communication infrastructure at medium or geosynchronous Earth orbit (MEO or GEO), to support the needs of future sensor systems. This communication infrastructure should be able to transfer information from a multitude of sensor-rate mobile uplinks (from groun... View full abstract»

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  • Update on PCS radio frequency issues

    Publication Year: 1992
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (64 KB)

    Summary form only given. PCS (personal communications service) incorporates a range of new wireless PBXs to rural microcells serving the over-the-road transportation industry. Each of these new services is the subject of a regulatory proceeding currently underway. In the case of spectrum, the Commission has proposed in the Emerging Technology Docket 92-9, 220 MHz of spectrum for new and emerging t... View full abstract»

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  • MILCOM '92 - 'Communications - Fusing Command, Control and Intelligence' Conference Record (Cat. No. 92CH3131-0)

    Publication Year: 1992
    Request permission for commercial reuse | PDF file iconPDF (104 KB)
    Freely Available from IEEE
  • The PR4G VHF ECCM system: extensive tactical communications for the battlefield

    Publication Year: 1992, Page(s):662 - 666 vol.2
    Cited by:  Papers (4)  |  Patents (20)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (529 KB)

    PR4G, a complete system for ECCM (electronic counter countermeasures) VHF tactical radio communications, is described. It has been developed to meet the requirements of the French army. Its characteristics, including enhancements and integration into the French C3I (command, control, communications, and intelligence) systems, are presented. The program and program management methodology are descri... View full abstract»

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  • Effect of CW and pulse jamming on direct-sequence spread-spectrum code acquisition using a sequential detector

    Publication Year: 1992, Page(s):638 - 643 vol.2
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (516 KB)

    The authors use a Monte-Carlo computer simulation to examine the effect of continuous-wave (CW) and pulse jamming, in the presence of additive Gaussian noise, on the acquisition performance of a noncoherent serial-search pseudonoise code synchronizer. The acquisition performances of three variants of the sequential detector, namely, the quantized log-likelihood detector, the biased square-law dete... View full abstract»

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  • A CDMA/framed-ALOHA protocol for voice/data integration in hybrid satellite/terrestrial networks

    Publication Year: 1992, Page(s):108 - 114 vol.1
    Cited by:  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (636 KB)

    The authors examine certain protocols for voice/data integration in hybrid satellite/terrestrial packet radio networks. In the ground subnetwork, code-division multiple-access with movable boundary in the code domain is used to serve the voice traffic and the retransmitted data traffic; on the satellite subnetwork, framed ALOHA with movable boundary is used for both data and voice. Based on a Mark... View full abstract»

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  • A neural network tunable filter for multi-tone detection

    Publication Year: 1992, Page(s):789 - 793 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (316 KB)

    A neural network that tunes to a band of frequencies depending on its inputs is proposed as a preprocessor for multiple sinusoid detection and estimation in additive noise. The multilayer perceptron network is trained off-line using the standard backpropagation algorithm. The authors provide a logical development of the problem and discuss the advantages of the proposed scheme. Potential applicati... View full abstract»

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  • Digital tracking loops for a programmable digital modem

    Publication Year: 1992, Page(s):644 - 650 vol.2
    Cited by:  Papers (3)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (676 KB)

    An analysis and hardware emulation of the tracking loops for a very flexible programmable digital modem are presented. The modem can be programmed for 2, 4, 8, 16 PSK (phase shift keying), 16-QAM (quadrature amplitude modulation), MSK (minimum shift keying), and offset-QPSK modulation schemes over a range of data rates from 2.34 to 300 Mb/s with programmable spectral occupancy from 1.2 to 1.8 time... View full abstract»

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  • Simulated annealing optimization in blind equalization

    Publication Year: 1992, Page(s):216 - 220 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (432 KB)

    A novel adaptation method based on simulated annealing is introduced for blind equalization. The existing Bussgang-type blind equalization algorithms are based on the minimization of nonlinear cost functionals, utilizing a stochastic gradient approach. Due to the multimodal nature of these functionals, the gradient algorithms might converge to the wrong solution. The proposed method is based on a ... View full abstract»

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  • Performance analysis of a spread spectrum acquisition algorithm for satellite mobile radio

    Publication Year: 1992, Page(s):115 - 119 vol.1
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (412 KB)

    The authors consider the parallel acquisition of direct-sequence spread-spectrum signals with very low signal-to-noise ratio (SNR) and with frequency and pseudonoise chip clock epoch uncertainty due to Doppler. This problem arises in the context of low-earth-orbiting satellite-based mobile radio networks where the Doppler effect induces both large initial uncertainty and considerable dynamics duri... View full abstract»

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  • On alphabet size selection for video signal coding

    Publication Year: 1992, Page(s):794 - 798 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (344 KB)

    Communications systems with various alphabet sizes for transmission of video signals are compared on the basis of equal information rate, bandwidth, and average power. Two cases are considered: when the bandwidth constraint is tight and when it is somewhat loose. It is observed that the ternary alphabet yields the best performance among the systems employing various alphabet sizes, when the bandwi... View full abstract»

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  • Interoperability of tactical radios among members of NATO

    Publication Year: 1992, Page(s):651 - 654 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (324 KB)

    The authors identify the North Atlantic Treaty Organization (NATO) requirements for standardization agreements concerning combat net radio interoperability. These agreements will replace the existing liaison procedures for providing cooperation and understanding between commanders and staffs of headquarters and forces that are working together. The design and operation of an interface unit that pr... View full abstract»

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  • Object-oriented modeling of communication systems

    Publication Year: 1992, Page(s):68 - 72 vol.1
    Cited by:  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (516 KB)

    The authors discuss the basic attributes of an object-oriented (OO) model and examine why this may be an attractive simulation architecture. Attention is given to three concepts that are fundamental in OO modeling and programming: encapsulation, inheritance, and polymorphism. The authors are currently developing an OO communication system simulation that demonstrates the principles mentioned. By m... View full abstract»

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  • DMS message precedence in the GOSIP environment

    Publication Year: 1992, Page(s):1205 - 1209 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (612 KB)

    The authors describe the implications of Defense Message System (DMS) message time-of-delivery requirements in the Government Open Systems Interconnection Profile (GOSIP) environment. DMS precedence/priority handling mechanisms and their implementation in the protocols in the GOSIP stack are examined. It is shown that there are precedence-related mechanisms available in the communications protocol... View full abstract»

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  • Interference nulling in direct-sequence spread-spectrum systems using a main-beam reference in the delay space

    Publication Year: 1992, Page(s):468 - 472 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (376 KB)

    The authors discuss an interference nulling technique that transforms the output vector of a linear antenna array to a vector made of independent beams in the delay space. The signal of interest (SOI) is located in the center of a main beam in the delay space and is used as a reference in two steepest-descent feedback algorithms to null interference appearing on the remaining beams. When direct-se... View full abstract»

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  • Fractionally-spaced blind equalization with CRIMNO algorithm

    Publication Year: 1992, Page(s):221 - 225 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (392 KB)

    The CRIMNO criterion is extended to the case of fractionally spaced blind equalization. Simulation results show that the fractionally spaced CRIMNO algorithm, especially its adaptive version, converges faster than the synchronous CRIMNO algorithm, and faster than the fractionally spaced Goddard (1980) CMA algorithm. Insights into why the fractionally spaced blind equalization algorithm has faster ... View full abstract»

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  • On the capacity of DS-CDMA systems in a Nakagami multipath channel

    Publication Year: 1992, Page(s):120 - 124
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (332 KB)

    The coherence reception of direct-sequence/code-division multiple-access (DS/CDMA) signals in a multipath fading channel is considered. The channel model assumes independent paths with Nakagami fading statistics; this model includes the Rayleigh channel as a special case and is a reasonable model for a frequency-selective fading channel. The bit error rate (BER) performance of a RAKE receiver unde... View full abstract»

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  • GSA's capabilities to support NSEP telecommunications

    Publication Year: 1992, Page(s):134 - 136 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (180 KB)

    The numerous essential as well as operational services that the US General Services Administration (GSA) can provide to all NSEP (National Security Emergency Preparedness) users during peacetime and wartime stress conditions are described. The Office of FTS2000 manages the program that provides long-distance telecommunications services to government locations throughout the United States, Puerto R... View full abstract»

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  • Cochannel uplink interference in PN spread QPSK satellite systems

    Publication Year: 1992, Page(s):1158 - 1162 vol.3
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (412 KB)

    The effect of a bandpass limiter in code division multiple access quadriphase shift keying (QPSK) satellite spread spectrum communication systems is investigated. The case of a cochannel interferer on the uplink is analyzed in detail. The nonlinear characteristics of the bandpass limiter result in the generation of intermodulation products which become narrowband signals after the despreading proc... View full abstract»

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  • GOBNET (Gigabit Object Network)

    Publication Year: 1992, Page(s):986 - 990 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (524 KB)

    The authors present an introduction to the high-level design of GOBNET, an ongoing research effort at the University of Pennsylvania to extend the Memmet distributed shared memory research to a wide-area environment. GOBNET also supports distributed object-oriented systems. The authors describe some of the issues in the design of GOBNET, including memory as the abstraction of wide-area-network, ob... View full abstract»

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  • A new block helical interleaver

    Publication Year: 1992, Page(s):799 - 804 vol.2
    Cited by:  Papers (11)  |  Patents (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (468 KB)

    The author describes a novel interleaving strategy, called the helical block (HB) interleaver, and discusses its efficient hardware implementation. The advantages of HB interleavers as compared with traditional interleavers, including block interleavers, convolutional interleavers, and helical interleavers, are discussed. A relationship between helical interleavers and convolutional interleavers i... View full abstract»

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  • VHF ECCM radio-Norwegian approach to interoperability

    Publication Year: 1992, Page(s):655 - 661 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (488 KB)

    Technical interoperability for modern and digital radios offering enhanced functionalities is addressed. A long-term strategy for a VHF ECCM (electronic counter countermeasures) radio is spelled out. Specifically, the Norwegian strategy for multirole radio interoperability implementation is described View full abstract»

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  • A time varying transform domain excision filter for interference rejection in direct-sequence spread-spectrum

    Publication Year: 1992, Page(s):908 - 912 vol.3
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (516 KB)

    The performance of a direct-sequence spread-spectrum (DSSS) receiver with a transform domain prefilter is presented. The ability of a time-varying transform domain filter to reject narrowband interference is studied for different parameters as a function of noise power and jammer power. Digital processing design trade-off issues such as the transform domain excision filter bandwidth and window fun... View full abstract»

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  • User-friendly software system for analyzing antennas and radiowave propagation links

    Publication Year: 1992, Page(s):73 - 76 vol.1
    Cited by:  Patents (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (408 KB)

    The authors describe a software system that simplifies the use of proven analysis codes by interfacing them with a user-friendly, Windows-based pre-/postprocessor. A user with only a basic understanding of PCs and Windows will be able to use the system to predict the performance of any antenna structure or communication link. This broad applicability is achieved by integrating a unique selection o... View full abstract»

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  • Policy based routing in the Defense Information System Network

    Publication Year: 1992, Page(s):1210 - 1214 vol.3
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (456 KB)

    It is noted that the routing protocol in the Defense Information System Network will most likely operate in a large environment with diversified policies. The author proposes a policy based routing architecture that would be a good candidate for this type of environment. The new architecture, IDPR (Inter-Domain Policy Routing) II, adopts a number of features from IDPR, such as link state update, s... View full abstract»

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