Non Data Aided Parameter Estimation for Multi-User ARGOS Receivers

In this paper, parameter estimators are analyzed in the context of Successive Interference Cancelation (SIC) receivers for the ARGOS system. A Non Data Aided (NDA) feed forward estimator is proposed for the amplitude and the carrier phase parameters. Time delays are assumed to be known. A Window Accumulator (WA) is used to reduce the influence of the additive noise. In the presence of frequency offset, the window length L cannot be chosen arbitrarily large but an optimal length Lopt can be determined. However, because the estimator induces a different optimal length for each parameter, a trade-off must be made. We show that a window length of around 35 samples induces mean square errors (MSEs) lower than 0.012 for both parameters. The MSE of the proposed estimator is also compared to the Modified Cram´er Rao Bound (MCRB)

Method of Non-Data-Aided Carrier Recovery with Modulation Identification

A non-data aided carrier recovery technique using digital modulation format identification called multi-mode PLL (Phase Locked Loop) is proposed. This technique can be interpreted as a modulation identification method that is robust against static phase and frequency offsets. The performance of the proposed technique is studied and the analytical expressions are derived for the probability of lock detection, acquisition time over AWGN channel in the cases of M-PSK and M-QAM modulations with respect to frequency offset and signal-to-noise ratio

A Method of Non-Data-Aided Carrier Recovery with Modulation Identification

A non-data aided carrier recovery technique using modulation format identification is proposed. This technique can also be interpreted as a modulation identification method that is robust against static phase and frequency offsets. The performance of the proposed technique is studied and analytical expressions derived for the mean acquisition time to detect lock in the cases of M-PSK, M=2,4,8, and 16-QAM modulation, with respect to frequency offset and signal-to-noise ratio. The results are verified with Monte Carlo simulations. The main advantage of the proposed method lies in its simpler implementation and faster lock detection, when compared to conventional methods

Non-Data-Aided Parameter Estimation in an Additive White Gaussian Noise Channel

Non-data-aided (NDA) parameter estimation is considered for binary-phase-shift-keying transmission in an additive white Gaussian noise channel. Cramer-Rao lower bounds (CRLBs) for signal amplitude, noise variance, channel reliability constant and bit-error rate are derived and it is shown how these parameters relate to the signal-to-noise ratio (SNR). An alternative derivation of the iterative maximum likelihood (ML) SNR estimator is presented together with a novel, low complexity NDA SNR estimator. The performance of the proposed estimator is compared to previously suggested estimators and the CRLB. The results show that the proposed estimator performs close to the iterative ML estimator at significantly lower computational complexity

Non-data-aided frequency offset and symbol timing estimation for binary CPM: performance bounds

The use of (spectrally efficient) CPM modulations may lead to a serious performance degradation of the classical non-data-aided (NDA) frequency and timing estimators due to the presence of self noise. The actual performance of these estimators is usually much worse than that predicted by the classical modified Cramer-Rao bound. We apply some well known results in the field of signal processing to these two important problems of synchronization. In particular we propose and explain the meaning of the unconditional CRB in the synchronization task. Simulation results for MSK and GMSK, along with the performance of some classical and previously proposed synchronizers, show that the proposed bound (along with the MCRB) is useful for a better prediction of the ultimate performance of the NDA estimators.Peer ReviewedPostprint (published version

Non-data-aided ML symbol timing estimation in MIMO correlated fading channels

In this paper, the non-data-aided (NDA) maximum likelihood (ML) symbol timing estimator in MIMO correlated channel is derived. It is found that the extended square nonlinearity estimator in [9] is just a special case of the proposed algorithm. Furthermore, the conditional Cramer-Rao bound (CCRB) and the modified Cramer-Rao bound (MCRB) are also established. Simulation results under different operating conditions (e.g., number of antennas and correlation between antennas) are given to assess the performances of the NDA ML estimator and it is found that the mean square errors (MSE)s of the NDA ML estimator i) are close to the CCRBs, but not the MCRBs; ii) are approximately independent of the number of transmit antennas; iii) are inversely proportional to the number of receive antennas and iv) correlation between antennas has little effect on the SE performance.published_or_final_versio

Blind Carrier Phase Recovery for General 2{\pi}/M-rotationally Symmetric Constellations

This paper introduces a novel blind carrier phase recovery estimator for general 2{\Pi}/M-rotationally symmetric constellations. This estimation method is a generalization of the non-data-aided (NDA) nonlinear Phase Metric Method (PMM) estimator already designed for general quadrature amplitude constellations. This unbiased estimator is seen here as a fourth order PMM then generalized to Mth order (Mth PMM) in such manner that it covers general 2{\Pi}/M-rotationally symmetric constellations such as PAM, QAM, PSK. Simulation results demonstrate the good performance of this Mth PMM estimation algorithm against competitive blind phase estimators already published for various modulation systems of practical interest.Comment: 14 pages, 12 figures, International Journal of Wireless & Mobile Networks (IJWMN

Data-aided single-carrier coherent receivers

Data-aided algorithms for coherent optic receivers are discussed as an extension of existing non-data aided methods. The concept presents a scalable approach with low implementation complexity and limited overhead for higher-order modulation formats

Non Data-Aided Carrier Tracking Techniques for Continuous-Phase Frequency-Shift Keyed Signals

Communications between ground stations and nanosats in low earth orbit (LEO) require acquisition and tracking of large Doppler frequency offsets due to the relative velocity between the transmitter and the receiver. The Doppler frequency shift varies with time, reaching its fastest rate of change as the small satellite reaches its closest approach to the ground station. For phase modulated signals, a frequency offset estimate extracted from the band edge filters is used to correct for the Doppler shift. This approach encounters difficulties when it’s used to correct for frequency offset in continuous phase frequency shift keyed (CPFSK) signals. Optimized band edge filters are designed to have a frequency response that is the derivative of the matched filter frequency response. However, CPFSK detection often requires different matched filters for different symbols, particularly when there are multiple possible magnitudes of frequency shifts to choose from in each symbol period. Having separate matched filters for different symbols complicates the effort to use optimized band edge filters as it imposes a requirement to demodulate the signal before correcting its frequency offset. Furthermore, the fact that the signal of interest is itself changing in frequency from one symbol to the next further complicates the issue. However, a modification to the classic band edge filter design can permit the detection and correction of CPFSK signals without the need to demodulate the signal. This paper presents techniques for non data-aided correction of CPFSK signals using modified matched filters in frequency locked loops (FLLs). Examples of the approaches are shown in MATLAB for varying signal-to-noise ratio (SNR), static Doppler, and dynamic Doppler