Download or read book Performance Analysis of Frequency Hopping MFSK M ary Frequency Shift Keying Systems Employing Forward Error Control Coding in the Presence of Hostile Interference written by Jhong S. Lee and published by . This book was released on 1987 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt: Error probability analyses are performed for a coded M-ary frequency-shift-keying (MFSK) system employing L hops per M-ary word frequency-hopping (FH) spread spectrum waveforms transmitted over a partial-band Gaussian noise jamming channel. The information bit error probabilities are obtained for a square-law linear combining demodulator and for a square-law adaptive gain control (AGC) demodulator, both with forward error control (FEC) coding under conditions of worst-case partial-band noise jamming, using exact analyses of the demodulator performance which include both thermal noise and jamming noise. Parametric performance curves are obtained for both block codes and convolutional codes with both binary and M-ary channel modulations. The results show that thermal noise can not be neglected in the analyses if correct determinations of the optimum order of diversity and the worst-case jamming fraction are to be obtained over the whole range of signal-to-thermal noise and signal-to-jamming ratios. It is shown that the combination of non-linear combining, M-ary modulation, and forward error control coding is an effective strategy against worst-case partial-band noise jamming. However, just as was found to be the case for uncoded systems, the linear combiner is ineffective in worst-case partial-band noise jamming. (Author).
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1987 with total page 964 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Reports Awareness Circular TRAC written by and published by . This book was released on 1987 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index written by and published by . This book was released on 1987 with total page 934 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sections 1-2. Keyword Index.--Section 3. Personal author index.--Section 4. Corporate author index.-- Section 5. Contract/grant number index, NTIS order/report number index 1-E.--Section 6. NTIS order/report number index F-Z.
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1987-10 with total page 716 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index Keyword A L written by and published by . This book was released on 1987 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the Conference on Information Sciences and Systems written by and published by . This book was released on 1987 with total page 794 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Anti jam Analysis of Frequency Hopping M ary Frequency Shift Keying Communication Systems in High Frequency Rayleigh Fading Channels written by Dan Avidor and published by . This book was released on 1981 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: A certain type of M-ary Frequency Shift Keying (MFSK) communication systems, which use Frequency Hopping (FH) to combat jamming is studied in this work. In particular, the performance of such systems over High Frequency (HF) sky-wave channels, when subjected to intentional jamming, is the main topic of this study. The channels considered are characterized by Rayleigh fading and additive Gaussian noise. To combat jamming the communication system hops over the total spread spectrum bandwidth, which is many times larger than the 'instantaneous' bandwidth occupied by the MFSK signal. Located within the HF band and using sky-wave as the dominant propagation mode, the spread spectrum bandwidth is typically nonuniform, time dependent, and congested by many other users of the electromagnetic spectrum. In such an environment, Frequency Hopping FH mfsk systems seem to be more practical than 'Direct Sequence' spectrum spreading techniques. A FH/MFSK system can be easily programmed to use a noncontiguous band, thereby avoiding strong interfering signals that should not be interfered with.
Download or read book Effect of Worst Case Multiple Jammers on Coded FH SSMA Systems written by Evaggelos Geraniotis and published by . This book was released on 1990 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report characterizes and evaluates the effect of simultaneous multiple partial-band noise or tone jammers and other-user interference on a single communication link employing frequency-hopped spread-spectrum (FH/SS) signaling, M-ary frequency-shift-keying (FSK) modulation with noncoherent demodulation, and Reed-Solomon coding. For the symbol error probability of these systems, we derive exact expressions in the absence of multiple-access (MA) interference and tight upper bounds in the presence of other-user interference. Although our analytical methods are valid for any number of multiple jammers, we restrict our numerical study to the cases of two and three partial-band noise and tone jammers. For fixed values of the spectral densities of noise jammers, or the energies per symbol of tone jammers, we evaluate the worst-case fraction of the band that each jammer should use in order to maximize the error probability of the FH/SS or FH/SSMA system. For the range of the signal-to-jammer power ratios examined, multiple noise or tone jammers appear to have no advantage over a single noise or tone jammer of equivalent spectral density or energy per symbol but achieve approximately the same worst-case performance by jamming smaller fractions of the band. Keywords: Jamming, Antijamming, Frequency hopping, Frequency shift keying, Spread spectrum, Multiuser interference, Multiple access, Error correction codes. (jhd).
Download or read book Frequency Hopped M arcy Frequency Shift Keyed Communications Using List Metric Decoding Over Jamming and Multiple Access Channels written by Mark A. Creighton and published by . This book was released on 1986 with total page 387 pages. Available in PDF, EPUB and Kindle. Book excerpt: List metric decoding is applied to anti-jam and multiple access communication systems that employ frequency-hopped, M-ary Frequency Shift Keyed (MFSK) modulation. The performance of these systems over Guassian noise and Rayleigh fading channels is analyzed by deriving expressions for the cutoff rate parameter RO, and evaluating numerical examples. RO represents the largest reliable data rate per coded symbol that could be achieved, with a particular system and channel, by using practical coding methods. Because it is code-independent, RO is used as the basis for comparing list decoding against hard and soft decisions, without the encumbrance of analyzing specific error correcting codes. RO is then used later, along with a code-dependent function, to upper bound the bit error probability provided by a particular code. In a list decoding receiver, decisions are based on the relative magnitudes of the demodulator's energy detector outputs.
Download or read book Vulnerability of Codes Using Frequency Shift Keying written by Ray H. Pettit and published by . This book was released on 1973 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: ING CODES, CONVOLUTIONAL CODES, DATA TRANSMISSION SYSTEMS, ERROR CORRECTION CODESThe report contains the details and results of a study of the susceptibility of a binary noncoherent frequency shift keying (NCFSK) detection system to various types of jamming signals. Probability-of-error expressions are derived for two types of jamming signals (CW and linear FM), serving as a beginning to a more complete theoretical susceptibility analysis. The manthematical model and the procedures used provide a basis for additional derivations involving non-Gaussian interference. Seven possible error-corr ction schemes are investigated and compared on the basis of: (1) tolerable binary symbol error rates for a given character error probability, and (2) the interference power levels associated with these error rates. System complexity is considered qualitatively. Recommendations are made concerning additional studies and system modifications. (Author).
Download or read book Frequency Hopping Multiple Frequency Shift Keying Coding and Optimal Partial Band Jamming written by Don J. Torrieri and published by . This book was released on 1982 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt: The performance of frequency-hopping systems with multiple frequency-shift keying is determined for operation against optimal partial-band jamming. The effects of Reed-Solomon, binary block, convolutional, and concatenated codes are analyzed. Continuous-phase frequency-shift keying with limiter-discriminato demodulation is shown to offer potentially improved performance in frequency-hopping systems. (Author).
Download or read book Electronic Counter Counter Measures Potential of a Noncoherent FH MFSK Communications System Under Conditions of Worst Case Hostile Electronic Counter Measures and Fading Channels written by George T. Katsoulis and published by . This book was released on 1997-03-01 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis investigates the performance degradation resulting from multitone interference of orthogonal, noncoherent, frequency-hopped, M-ary frequency-shift keyed receivers (FH/MFSK) where the effect of thermal and other wideband noise is not neglected. The multiple, equal power jamming tones are assumed to correspond to some or all of the possible FH M-ary orthogonal signaling tones. Furthermore, the channel is modeled as a Ricean fading channel, a possibility precluded when thermal noise is neglected. Both the signaling tones and the multiple interference tones are assumed to be affected by channel fading. Both band and independent band multitone interference are considered. Performance is evaluated by obtaining a union bound on the probability of bit error, and receiver performance is compared with exact results for band multitone interference of a noncoherent FH/MFSK receiver under comparable circumstances. Except for the case of Rayleigh fading of the signal, the union bound is very tight for those cases that can be compared with exact results. The advantages of the union bound approach are twofold. First, the union bound approach yields a solution that is far less computationally intensive than that obtained with the exact approach. Second, the union bound approach allows numerical results to be obtained for interference conditions that are not amenable to exact analysis, such as independent multitone interference of FH/ MFSK.
Download or read book Performance Analysis of Coded Frequency Hopped Spread Spectrum Systems with Unknown Interference written by M. V. Hedge and published by . This book was released on 1987 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two classes of problems are considered. In the first class we model the process of communicating in the presence of interference, which is unknown or hostile, as a two-person zero sum game with the communicator and the jammer as the players. The objective functions we consider are mutual information and the channel cutoff rate. The communicator's strategies are distributions on the input alphabet and on a set of quantizers and the jammer's strategies are distributions on the noise power subject to certain constraints. We consider various conditions on the jammer's strategy set and on the communicator's knowledge. For the case with the decoder uninformed of the actual quantizer chosen, we show that, from the communicator's perspective the worst-case jamming strategy is a distribution concentrated at a finite number of points thereby converging a functional optimisation problem into a nonlinear programming problem. Moreover, we are able to also characterize the worst-case distributions by means of necessary and sufficient conditions which are easy to verify. For the case with the decoder informed of the actual quantizer chosen we are able to demonstrate the existence of saddle-point strategies.
Download or read book Performance of Frequency hopped M ary FSK in the Presence of Phase Jitter written by J. W. T. Yau and published by . This book was released on 1984 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Performance of M ary Orthogonal Continuous Phase FSK Frequency Shift Keying for a Trans Ionospheric Time Varying Frequency Selective Channel written by David Peavey and published by . This book was released on 1985 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: M-ary Orthogonal continuous Phase FSK modulation can significantly improve severe frequency-selective channel Bit Error Rate over conventional modulation techniques. This modulation technique has the potential to enhance the performance of channel equalizers and error correction and coders in a selective channel.
Download or read book Performance Analysis of FFH MFSK Under Jamming Using Diversity and Coding written by Srinivas Polavarapu and published by . This book was released on 2004 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:
