By Topic

Military Communications Conference, 1996. MILCOM '96, Conference Proceedings, IEEE

24-24 Oct. 1996

Go

Filter Results

Displaying Results 1 - 25 of 80
  • IEEE Military Communications Conference - Milcom 96 [front matter]

    Publication Year: 1996, Page(s):i - xxiv
    Request permission for commercial reuse | PDF file iconPDF (843 KB)
    Freely Available from IEEE
  • A near optimum diversity combining method adapted to slow frequency hopping DPSK transmission

    Publication Year: 1996, Page(s):984 - 987 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (370 KB)

    Frequency hopping (FH) is used in communication systems to mitigate interference such as jamming. For low data rate, fast FH and MFSK are often used in combination with diversity, which consists in transmitting every symbol on several hops. It brings additional protection. Several robust diversity combining methods have been developed previously for fast FH. Much attention has been previously focu... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Conference Author Index

    Publication Year: 1996, Page(s):1084 - 1086
    Request permission for commercial reuse | PDF file iconPDF (143 KB)
    Freely Available from IEEE
  • Useful new results on the time to lose lock for a simple Markov tracking scheme

    Publication Year: 1996, Page(s):806 - 810 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (412 KB)

    We study the time to lose lock of a simple and popular Markov tracking scheme wherein a signal or status indicator is monitored every T seconds. Loss of tracking is declared if the signal is not detected for s consecutive time units; otherwise, tracking is maintained. To date, there exists a closed form expression for the mean time to lose lock E[TLL] and also an expression involving a matrix inve... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Joint maximum-likelihood data and bit synchronization epoch estimation for burst direct sequence spread-spectrum transmission

    Publication Year: 1996, Page(s):801 - 805 vol.3
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (508 KB)

    We derive the optimal joint maximum-likelihood (ML) estimator of the bit synchronization epoch and data bit values for a short burst direct-sequence spread-spectrum (DSSS) transmission, for both the white and colored noise environments. The DSSS signal is assumed already downconverted and despread. We show that the additional computational burden incurred by using the estimator derived for the col... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Generalized sliding window algorithm with applications to frame synchronization

    Publication Year: 1996, Page(s):796 - 800 vol.3
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (392 KB)

    All frame synchronization systems have a part that detects out-of-frame condition. This paper proposes a generalized sliding window algorithm for out-of-frame detection. This algorithm includes a large number of new schemes not previously considered. The essential statistical properties of the algorithm are given for a range of cases. The algorithm and the associated statistical analysis can be ex... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Frequency offset compensator for land mobile zero-crossing digital FM receiver

    Publication Year: 1996, Page(s):745 - 749 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (448 KB)

    A base-band demodulator called zero-intermediate frequency zero-crossing demodulator (ZIFZCD) was developed. The ZIFZCD is mostly implemented in digital hardware which offers low power consumption, small size and ease of manufacture. The frequency offset effect on the performance of the ZIFZCD has been studied and a significant bit error rate (BER) degradation has been observed. Two frequency offs... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Diversity combining for M-ary fast frequency hopping multiple-access Rayleigh fading channel

    Publication Year: 1996, Page(s):893 - 897 vol.3
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (416 KB)

    This paper investigates four diversity combining techniques for a fast frequency hopped spread-spectrum multiple-access (FFH/SSMA) communications system. A single cell system is considered with multiple-access interference, additive white Gaussian noise and Rayleigh fading. The modulation is M-ary frequency shift keying with non-coherent detection at the receiver. The system performance is evaluat... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Antenna downtilt performance in urban environments

    Publication Year: 1996, Page(s):739 - 744 vol.3
    Cited by:  Papers (2)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (688 KB)

    This paper discusses antenna downtilt concepts and performance in an actual operating cellular system, the relationship between antenna height, downtilt angle, and coverage radius is also discussed. Theoretical calculation and actual operating data collected from the cellular system are compared. We draw the two following conclusions. In modern urban propagation environments, the coverage area con... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • CHESS a new reliable high speed HF radio

    Publication Year: 1996, Page(s):684 - 690 vol.3
    Cited by:  Papers (52)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (608 KB)

    This paper presents the design and performance of an advanced digital signal processing (DSP) based high frequency (HF) radio developed (patent pending) by Sanders, a Lockheed Martin Company. The radio is called Correlated Hopping Enhanced Spread Spectrum (CHESS). CHESS represents a new generation of spread spectrum HF radio technology, designed to enhance spectrum sharing while providing reliable... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Suboptimal Viterbi decoding metrics for channels with pulse jamming

    Publication Year: 1996, Page(s):1032 - 1035 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (276 KB)

    The tradeoff between complexity and performance of decoding metrics for use with Viterbi decoding has been studied for a channel with Gaussian pulse jamming. It is shown that a metric with three-bit quantization provides a good combination of robust performance and low complexity. In addition, a new variable rate coding scheme which utilizes soft information from the quantizer is described. The pe... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Higher-order correlation-based classification of asynchronous MFSK signals

    Publication Year: 1996, Page(s):1003 - 1009 vol.3
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (628 KB)

    The problem of asynchronous classification of M-ary frequency shift keying (MFSK) signals when contaminated by additive white Gaussian noise (AWGN) is addressed. Two approaches are adopted. The first is based on the classical likelihood-ratio theory which provides performance that is optimal but sensitive to unknown frequency offsets. The second completely eliminates the fixed-frequency structure ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Analysis of a DPSK link with on board processing and diversity for medium data rate EHF frequency hopping systems: compromise between the SATCOM system operating and jamming performances

    Publication Year: 1996, Page(s):1064 - 1068 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (396 KB)

    We analyse a DPSK link with on-board-processing and diversity combining features for medium data rate frequency hopping systems. In a system approach, we address the following questions. (1) What is the optimum diversity combining solution that can both multiplex the data rates and protect the system against jammers? (2) What is the best compromise between satellite transmitted power, ground termi... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The simulation of adaptive antennas

    Publication Year: 1996, Page(s):887 - 892 vol.3
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (556 KB)

    This paper describes how a simulation of an adaptive satellite antenna may be designed in order to combine modeling fidelity and flexibility, using experience gained in constructing just such a simulation. It discusses the broadband modeling of user and jammer signals, and their propagation through the hardware components, as well as the modeling of the system's adaptive response to them. The moni... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Simplification of the MUSIC algorithm using a neural network

    Publication Year: 1996, Page(s):873 - 876 vol.3
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB)

    The computation of the MUSIC null spectrum and the search for its minima constitute the most demanding computations for the MUSIC algorithm. The time delay entailed can limit the direction-finding performance under nonstationary conditions. In this paper a neural network that directly maps the noise eigenvectors into the spectral minima is described View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Efficient lattice filtering algorithms and architectures

    Publication Year: 1996, Page(s):859 - 862 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (312 KB)

    Simplified Gaussian driven nonlinear lattice filters are derived. Like the linear whitener, the Gaussian nonlinear whitener requires O(N) computations and still achieves a completely orthogonal basis. Simplification is afforded by exploiting the zero odd moment property of Gaussian signals and the knowledge of the eigenvalue spread contributing inputs View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Adaptive equalization of nonlinear digital satellite channels using a frequency-domain Volterra filter

    Publication Year: 1996, Page(s):843 - 848 vol.3
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (512 KB)

    The objective of this paper is to present a new structure for an adaptive nonlinear equalizer for digital transmission over a nonlinear satellite channel with PSK modulation. The adaptive nonlinear equalizer is based on a discrete frequency-domain, third-order Volterra filter with the multidimensional overlap-save filtering technique, and on the block least mean square (BLMS) algorithm for updatin... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Performance of 16-QAM demodulation in the rapid multipath environment

    Publication Year: 1996, Page(s):713 - 717 vol.3
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (428 KB)

    Land mobile communication systems must overcome the rapid changes in received signal amplitude and phase that result from multipath effects. The effects of multipath are most significant in applications where coherent demodulation is required, namely high-order QAM. In this paper, the effects of noise and multipath distortion on direct 16-QAM at microwave frequencies is described with the techniqu... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Joint location and Doppler estimation with fractional lower-order statistics

    Publication Year: 1996, Page(s):833 - 837 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (400 KB)

    In wireless distributed multimedia communication networks, the spatial selectivity of an array of sensors can be used in order to operate in close-frequency bands and suppress undesirable noise and interference in favor of the signal of interest. Our emphasis is in the development of methods for direction finding, null- and beam-steering, and waveform recovery in mobile networks. We develop angle ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Packet combining techniques for frequency-hop communication systems with partial-band interference

    Publication Year: 1996, Page(s):1027 - 1031 vol.3
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (460 KB)

    Two methods for combining packets in frequency-hop spread-spectrum systems that employ interleaving and Reed-Solomon coding are presented and analyzed for the partial-band interference channel. Bounded distance errors-and-erasures decoding and erasure generation by means of Viterbi's (1982) ratio-threshold test are incorporated in the analysis. Results of the analysis show that both combining sche... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Noncoherent PN code acquisition with data modulation-on under static and fading environments

    Publication Year: 1996, Page(s):998 - 1002 vol.3
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (352 KB)

    Almost all conventional spread-spectrum acquisition schemes assume no data modulation or transition during the acquisition period, because the performance of the acquisition process is significantly degraded when data is present. In practical applications, modulation-off requirements during acquisition period cause inconvenience and delays, such as request and acknowledgment before data transmissi... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Compensating frequency drift in DPSK systems via baseband signal processing

    Publication Year: 1996, Page(s):1059 - 1063 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB)

    A new baseband signal processing method for compensating frequency shift in DPSK systems is introduced. This method consists of a signal processor for initial acquisition of the frequency shift and a simple adaptive equalizer for tracking. The former is based on the observation that the effect of the frequency shift can be eliminated by using boundary values of the received baseband signal between... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Adaptive beam pointing

    Publication Year: 1996, Page(s):882 - 886 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (332 KB)

    A new technique to adaptively reduce main beam interference is described. Unlike conventional adaptive antenna techniques, this adaptive concept does not modify the pattern of the antenna, but rather reduces interference by repositioning the antenna beam to increase the signal to interference ratio. A closed loop technique repositions the antenna beam. Since the beam is repositioned rather than ad... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Estimation of distributed elevation and azimuth angles using linear arrays

    Publication Year: 1996, Page(s):868 - 872 vol.3
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (408 KB)

    Many results on the estimation of direction of arrival (DOA) have been obtained based on the assumption that the signal sources are point sources. Recently, it has been shown that signal source localization can be accomplished more adequately with distributed source models. In this paper, we consider modeling of S-dimensional distributed signal sources, in which a distributed source is represented... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Fast converging methods for multichannel blind equalization or separation of multipath mixtures

    Publication Year: 1996, Page(s):854 - 858 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (356 KB)

    Algorithms for adapting FIR filters can also be applied to adaptation of FIR separation matrices (with multipath) for source separation. Fast converging algorithms robust to eigenvalue disparity are of interest, such as the exact least squares methods from the area of adaptive filters. Time domain adaptive multichannel blind recursive least squares (MBRLS) is presented. Three frequency domain algo... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.