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4-7 Nov. 1991

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Displaying Results 1 - 25 of 245
  • Military Communications in a Changing World MILCOM, 91. Conference Record (Cat. No.91CH2981-9)

    Publication Year: 1991
    Cited by:  Patents (3)
    Request permission for commercial reuse | PDF file iconPDF (69 KB)
    Freely Available from IEEE
  • Structures for polyspectra-based blind equalizers

    Publication Year: 1991, Page(s):1272 - 1276 vol.3
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB)

    Equalization structures useful in polyspectra-based blind equalization are summarized and discussed. These structures can be used with different equalization algorithms and criteria and can be easily modified to equalize minimum, maximum, or mixed phase communication channels. Structural properties related to equalization criteria, transfer functions and algorithms, noise and error propagation eff... View full abstract»

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  • Performance of convolutionally coded chip combiner and signal level based erasure DS receivers in pulsed noise interference

    Publication Year: 1991, Page(s):262 - 266 vol.1
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (300 KB)

    The performance of a chip combiner and a signal-level-based erasure direct-sequence (DS)/BPSK receiver was analyzed with Monte-Carlo simulations in an additive white Gaussian noise (AWGN) channel and in pulsed WGN interference using BPSK modulation and an optimum convolutional code of constraint length 7 and code rate 1/2. The receivers employ a soft decision Viterbi decoder. The receiver structur... View full abstract»

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  • Analytical linkage between theoretically-optimum and adhoc step-size establishment for nonstationary LMS filtering

    Publication Year: 1991, Page(s):1266 - 1271 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (420 KB)

    For nonstationary LMS adaptive filtering, results are presented which help bridge the gap between ideal theoretical, optimal step-sizes and practical, ad hoc, automatically established step-sizes. An analytical derivation is presented which demonstrates that for the nonstationary system identification paradigm a novel automatic step-size establishment technique estimates the theoretically optimum ... View full abstract»

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  • Comparative study on the performance of power and bandwidth efficient modulations in LMSS under fading and interference

    Publication Year: 1991, Page(s):257 - 261 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (324 KB)

    Aspects of error performance of various power and bandwidth efficient modulations for the land mobile satellite systems (LMSS) were investigated under multipath fading and interferences by using Monte-Carlo simulation. A differential detection for 16QAM (quadrature amplitude modulation) was proposed to cope with Rician fading and Doppler shift. Computer simulation results show that the performance... View full abstract»

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  • The recursive suppression algorithm for adaptive superresolution

    Publication Year: 1991, Page(s):1259 - 1265 vol.3
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (348 KB)

    The recursive suppression algorithm is an adaptive algorithm that is one of the simplest superresolution algorithms to implement but, nevertheless, converges almost as rapidly as the computationally intensive MUSIC algorithm. Simulation results verify the effectiveness of this algorithm in resolving closely spaced signals. Necessary and sufficient conditions for the convergence of the mean weight ... View full abstract»

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  • Coding techniques for memory and delay efficient interleaving in slow Rayleigh fading

    Publication Year: 1991, Page(s):252 - 256 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (408 KB)

    The objective has been to find memory-efficient coding/interleaving techniques and to accurately quantify their memory requirements. Toward this objective, convolutional interleaving, differential phase shift keying (DPSK) modulation, and various convolutional codes, Reed-Solomon codes, and concatenated convolutional and Reed-Solomon codes were evaluated by high-fidelity link simulations. Their in... View full abstract»

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  • A new algorithm for correcting single burst errors with Reed-Solomon codes

    Publication Year: 1991, Page(s):1254 - 1258 vol.3
    Cited by:  Papers (2)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (252 KB)

    The author presents a fast algorithm which can correct a single burst error length up to n-k-1 for a RS (n, k) code. Several methods which can reduce the probability of misdecoding if the length of the burst is longer than [(n-k )/2] are discussed. An RS (Reed-Solomon) decoder design is proposed which performs a regular error correction and the... View full abstract»

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  • Evaluation of a distributed TDMA rescheduling procedure for mobile packet radio networks

    Publication Year: 1991, Page(s):1167 - 1171 vol.3
    Cited by:  Papers (2)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (416 KB)

    A methodology, consisting of three procedures, that maximizes the use of the bandwidth for a TDMA (time-division multiple access) schedule and allows mobile nodes to locally reschedule transmission slots is described. To evaluate the performance, the methodology is implemented in a detailed radio network simulation. The parameters incorporated into the simulation include the network topology, the ... View full abstract»

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  • An adaptive nulling system digital microwave radio

    Publication Year: 1991, Page(s):246 - 251 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (372 KB)

    An adaptive antenna preprocessor for an equalized demodulator is described. The adaptive antenna preprocessor is used to spatially null undesired directional interference by linearly combining the signal received by two antennas. A 64-tap adaptive equalizer contained within the digital demodulator is used to remove adjacent channel and intersymbol interference. The adaptive algorithms do not requi... View full abstract»

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  • Measuring GOSIP's appropriateness for the tactical user

    Publication Year: 1991, Page(s):159 - 165 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (316 KB)

    The authors describe a proof-of-concept prototype system developed to measure communications performance and identify specific issues and problems that are likely to be encountered by tactical applications using the Government Open Systems Interconnection Profile (GOSIP). The prototype runs a tactical messaging application. Its functional topology, based on automation in command posts, and facilit... View full abstract»

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  • An efficient channel coding scheme for direct sequence CDMA systems

    Publication Year: 1991, Page(s):1249 - 1253 vol.3
    Cited by:  Papers (2)  |  Patents (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (312 KB)

    The author introduces an efficient modulation/coding scheme for direct-sequence (DS) spread-spectrum (SS) code division multiple access (CDMA) networks. The transmitter is allowed to choose between multiple spreading sequences, thus adding redundancy to the transmitted bit stream as well as providing multi-user interference rejection. The multiple code sequences assigned to each user are taken to ... View full abstract»

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  • The digital voice terminal for slow-FH radio application

    Publication Year: 1991, Page(s):1162 - 1166 vol.3
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB)

    The authors present a real-time digital voice terminal (DVT) for slow frequency-hopping (slow-FH) radio applications to ensure a reliable radio link. Slow-FH technologies have been introduced for ECCM communications as a near-term solution which will not disturb the usage of the present conventional radio spectrum. Digital secure algorithms with digital speech codec are known to achieve a high deg... View full abstract»

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  • Loading and spatial location in wire and radio communications networks

    Publication Year: 1991, Page(s):391 - 395 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (300 KB)

    Two algorithms and related performance measures for calculating traffic intensity as a function of spatial location are presented. The first measure of traffic loading is the product of the number of links per area, the average link distance, and the average load per link in a given area. This measure gives a sense of the joint amount of traffic load and cabling for wire networks. The second measu... View full abstract»

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  • A versatile adaptive array for LINK-11 communications

    Publication Year: 1991, Page(s):241 - 245 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    LINK-11 is an automated, one- or two-way, HF data link to distribute information within the Navy Tactical Data System. The null out, beam up, and lock on LINK-11 (NOBULL-11) adaptive antenna array (AAA) was developed to reduce the effects of cochannel interference on LINK-11 communications. The authors describe the NOBULL-11 AAA and performance results obtained during testing of the system with a ... View full abstract»

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  • A new frequency hopping-multilevel FSK system for mobile radio

    Publication Year: 1991, Page(s):154 - 158 vol.1
    Cited by:  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (292 KB)

    The authors discuss the problem of designing a frequency hop-multilevel frequency shift keying (FH-MFSK) code division multiple access (CDMA) system for applications in mobile radio. The need for such system is explained, and a system is proposed. The system is shown have the capability of servicing an increased number of users in the same available frequency bandwidth with a higher spectral effic... View full abstract»

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  • Convolutional projection codes

    Publication Year: 1991, Page(s):1245 - 1248 vol.3
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (192 KB)

    The convolutional projection code is presented. Encoding and decoding processes are reviewed, and hardware complexity and performance data are presented. Estimates of the error rates of the code as obtained by computer simulations are presented. The results showed that the code uses very simple encoding and decoding procedures which are easily implemented. Results also showed that the code outperf... View full abstract»

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  • A new wideband HF simulation system for testing HF radios

    Publication Year: 1991, Page(s):1156 - 1161 vol.3
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (348 KB)

    The authors describe the hardware/software implementation of a high-frequency (HF) simulation system that can be used for the real-time testing of HF communication systems. The simulator system implements novel propagation and noise/interference models as well as models of jamming signals. the system uses an architectural design that permits significant flexibility in the implementation of the mod... View full abstract»

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  • Order statistics diversity combining in worst case noise and multitone jamming

    Publication Year: 1991, Page(s):385 - 389 vol.1
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (364 KB)

    A previously known diversity combining method which uses order statistics (OS) has been investigated in both noise and multitone jamming. Based on the results of this investigation, a concatenation of order statistics and normalized envelope detection (NED) is proposed. Unlike many other proposed methods, no jammer state information is required. Simulation results in jamming showed that the OS-NED... View full abstract»

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  • Message reconstruction design criteria

    Publication Year: 1991, Page(s):991 - 994 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (236 KB)

    It is noted that there has been increased activity recently in developing computer algorithms that can automatically reconstruct messages received over record communications systems. These algorithms exploit the redundancy available when either multiple copies are transmitted or the message is expanded in the phonetic alphabet. The authors describe the characteristics of the communications systems... View full abstract»

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  • A study on antenna pointing for a cluster of users

    Publication Year: 1991, Page(s):238 - 240 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (164 KB)

    Pointing a space station antenna for the coverage of a cluster of users is studied. Suppose a single antenna located on a space station is mechanically steerable for the coverage of a few users, and the goal of the antenna pointing is to minimize the maximum pointing loss among the users. Mathematically, this is a nonlinear optimization problem. Assuming that all the users are within the mainbeam ... View full abstract»

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  • Transmission power optimization of multi-hop spread spectrum packet radio networks

    Publication Year: 1991, Page(s):149 - 153 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB)

    The authors present a model for the analysis of multihop spread spectrum packet radio networks and investigate their performance under various configurations. The analysis incorporates several network parameters such as topology, end-to-end traffic, routing, and node transmission power. The results reveal that high localization of the end-to-end traffic improves the network throughput and results ... View full abstract»

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  • Low cost approach for a space based data relay

    Publication Year: 1991, Page(s):658 - 666 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (496 KB)

    A low-cost system approach is presented for meeting the US Department of Defense requirement of continuous communications connectivity with low Earth orbit (LEO) spacecraft under test. The concept of using geostationary Earth orbit (GEO) satellites for the LEO data relay is considered. A low-cost near-term approach for such a space-based data relay system would utilize two existing Defense Satelli... View full abstract»

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  • A modern concept for the command post communication network

    Publication Year: 1991, Page(s):717 - 721 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB)

    The author provides an analysis of the communication requirements of command posts. A flexible, user-friendly, and economical communications system is defined and presented. The system was designed with small autonomous, high-capacity command post switches with a range of services. The design incorporated extensive use of application specific integrated circuits. The users access the system throug... View full abstract»

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  • Performance analysis of a ratio-threshold diversity combining scheme in FFH/FSK spread spectrum systems under multitone jamming

    Publication Year: 1991, Page(s):1240 - 1244 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (372 KB)

    A nonlinear diversity combining scheme using the Viterbi radio-threshold technique is discussed. The performances of the radio-threshold diversity combiner in fast frequency-hop spread-spectrum systems with M-ary frequency shift keying modulation (FFH/MFSK) under band multitone jamming without and with additive white Gaussian noise are analyzed. The exact bit error probabilities are compu... View full abstract»

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