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For free-space optical (FSO) links in turbulent atmosphere modeled by gamma-gamma distributions, an approximation of the pairwise error probability (PEP) was derived for on-off keying in a recently published paper. It has been assumed that the channel state is perfectly known to the receiver and that the fading samples are independent and identically(More)
The recently published Cramer-Rao lower bound for non-data-aided (NDA) estimation of the signal-to-noise ratio (SNR) reveals a considerable gap, when compared to the jitter performance of NDA algorithms available from the open literature. The maximum-likelihood (ML) solution derived in this paper closes this gap. However, the latter provides a set of two(More)
—Signal-to-noise ratio (SNR) estimation for linearly modulated signals is addressed in this letter, focusing on envelope-based estimators, which are robust to carrier offsets and phase jitter, and on the challenging case of nonconstant modulus constellations. For comparison purposes, the true Cramér-Rao lower bound is numerically evaluated, obtaining an(More)
—Signal processing in satellite applications is usually performed either on-ground or on-board, i.e. at the gateway station or in the payload. Within the framework of the European Space Agency (ESA) SatNEx III study, a hybrid approach has been considered by splitting the processing between the satellite and the gateway, aiming to strike a better balance(More)
The signal-to-noise ratio (SNR) estimation problem is addressed for linearly modulated signals over flat-fading channels. A new SNR estimator based on the expectation-maximization algorithm is proposed in order to iteratively maximize a certain approximation to the envelope-based likelihood function. The new method is robust to carrier offsets and can be(More)