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Proceedings ArticleDOI

An efficient coherent demodulation algorithm for TETRA communication system

01 Aug 2014-pp 642-643
TL;DR: The algorithm proposes frequency offset error twice-estimation and sectioned phase offset compensation to achieve the high precision in carrier synchronization and Odd-even decision is then proposed in the algorithm to avoid signal noise ratio (SNR) loss in differential demodulation.
Abstract: This paper describes an efficient coherent demodulation algorithm aiming at the receiver in Terrestrial Trunked Radio (TETRA) communication system. The algorithm proposes frequency offset error twice-estimation and sectioned phase offset compensation to achieve the high precision in carrier synchronization. Odd-even decision is then proposed in the algorithm to avoid signal noise ratio (SNR) loss in differential demodulation. The simulation has confirmed that the precision of frequency offset error twice-estimation is better than that of data-aided (DA) estimation and that compared with differential demodulation, the bit error rate (BER) performance of coherent demodulation is much better.
Citations
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Proceedings ArticleDOI
01 Aug 2014
TL;DR: Series of experiments tested on the published Enron email data set show that the multiple evidence fusion based diffusion model (MEFDM) is reasonable and feasible in demonstrating the cascading of information in the social network.
Abstract: Study on diffusion behaviors, such as contagion of virus, adoption of production, and information propagation, is one of the hottest topics of social network research. The conventional models usually focus on a particular factor that influences the contagion process. A novel model of diffusion based on multiple behavior evidence fusion is proposed on the analysis of prevalent social network data set, which can simulate the information propagation process with the fitting goodness of 0.79. In this model, impact factors, i.e. the influence between neighborhood, and the activity of user, are taken into account together and fused into combined evidence mass function, which can be used to infer users' forwarding behavior by D-S theory reasoning. Series of experiments tested on the published Enron email data set show that the multiple evidence fusion based diffusion model (MEFDM) is reasonable and feasible in demonstrating the cascading of information in the social network.

4 citations

References
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Journal ArticleDOI
TL;DR: A novel frequency estimator for a single complex sinusoid in complex white Gaussian noise is proposed that is more computationally efficient that the optimal maximum-likelihood estimator yet attains equally good performance at moderately high signal-to-noise ratios.
Abstract: A novel frequency estimator for a single complex sinusoid in complex white Gaussian noise is proposed. The estimator is more computationally efficient that the optimal maximum-likelihood estimator yet attains equally good performance at moderately high signal-to-noise ratios. The estimator is shown to be related to the linear prediction estimator. This relationship is used to reveal why the linear prediction estimator does not attain the Cramer-Rao bound even at high signal-to-noise ratios. >

732 citations


"An efficient coherent demodulation ..." refers background in this paper

  • ...…after phase decisions according to Table I [3] is ( ) 0 1decision ky k d k N= ≤ ≤ − (3) When noise is small, make the conjugate multiplication between (2) and (3) ( ) ( )12 0 1j f f Ty k e k Nπ ∆ −∆∆ ≈ ≤ ≤ − (4) Averaging the error over N points, get the frequency offset estimation error 2f∆ ....

    [...]

  • ...…− ≤ ≤ − (5) After sectioned phase compensation Supported by China Electronic Information Industry Development Fund – IOP Test and Verification System of TETRA Digital Trunking System 978-1-4799-5970-9 © 2014 IEEE642 ( ) ( ) ( )2 3 ( 1) 1ej f f kTcn ky k c e n k n M k nMπ ∆ −∆= + − ≤ ≤ − (6) The…...

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  • ...( ) ( )2 ( 1) 1j fkTn ky k c e n k n M k nMπ∆= + − ≤ ≤ − (5) After sectioned phase compensation Supported by China Electronic Information Industry Development Fund – IOP Test and Verification System of TETRA Digital Trunking System 978-1-4799-5970-9 © 2014 IEEE642 ( ) ( ) ( )2 3 ( 1) 1ej f f kTcn ky k c e n k n M k nMπ ∆ −∆= + − ≤ ≤ − (6) The sectioned signal after phase decisions which will be described in detail in Section III is given as ( ) ( 1) 1n kyd k c n M k nM= − ≤ ≤ − (7) Make the conjugate multiplication between (6) and (7)....

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Journal ArticleDOI
TL;DR: In this paper, the performance degradation caused by the frequency offset between the local oscillator and the unmodulated carrier in the baseband differential detector is studied and the performance of both coherently and differentially detected pi/4-QPSK in a Gaussian channel is also studied.
Abstract: The use of pi /4 quadrature phase-shift keying(QPSK) modems for satellite sound broadcast systems (SSBS) broadcasting to mobile or portable receivers is proposed. Three different differential detectors (including the FM-discriminator followed by integrate-sample-and-dump filter) and a novel coherent detector are discussed. The degradation caused by the frequency offset between the local oscillator and the unmodulated carrier in the baseband differential detector is studied. The performance of both coherently and differentially detected pi /4-QPSK in a Gaussian channel is also studied. It is shown that with a frequency offset of more than 3% of the symbol rate, the performance degradation is more than 1 dB at 10/sup -4/. The out-of-band power of the nonlinearly amplified bandlimited pi /4-QPSK signals is reduced from -13 dB to -37 dB if a 2-dB output back-off amplifier is used instead of a hardlimiter. The performance of the pi /4-QPSK is equivalent to that of QPSK, although the pi /4-QPSK has the advantage of less spectrum restoration after nonlinear amplification. The coherent demodulator and differential decoder avoid the three-level detection and achieve the same bit-error-rate (BER) performance as DEQPSK with a simple circuit. >

37 citations


Additional excerpts

  • ...Simulate 1000 times per symbol....

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Journal Article
TL;DR: Computer simulation results show that the data aid carrier synchronization scheme just spends 10 symbols for initial phase acquisition when SNR=10dB, and the normal QPSK phase tracking loop is suitable for π/4-DQPSK.
Abstract: A data aid carrier synchronization scheme for high rate burst mode communication systems is presented in this paperComputer simulation results show that the scheme just spends 10 symbols for initial phase acquisition when SNR=10dBIn addition,by-π/4 phase rotator,the normal QPSK phase tracking loop is suitable for π/4-DQPSK

1 citations

Proceedings ArticleDOI
01 Jan 2012

1 citations


"An efficient coherent demodulation ..." refers background in this paper

  • ...…after phase decisions according to Table I [3] is ( ) 0 1decision ky k d k N= ≤ ≤ − (3) When noise is small, make the conjugate multiplication between (2) and (3) ( ) ( )12 0 1j f f Ty k e k Nπ ∆ −∆∆ ≈ ≤ ≤ − (4) Averaging the error over N points, get the frequency offset estimation error 2f∆ ....

    [...]