

We consider distributed recursive estimation of an unknown vector parameter θ* ∈ ℝM in the presence of impulsive communication noise. That is, we assume that interagent communication is subject to an additive communication noise that may have heavy-tails or is contaminated with outliers. To combat this effect, within the class of consensus+innovations distributed estimators, we introduce for the first time a nonlinearity in the consensus update. We allow for a general class of nonlinearities that subsumes, e.g., the sign function or componentwise saturation function. For the general nonlinear estimator and a general class of additive communication noises-that may have infinite moments of order higher than one-we establish almost sure convergence to the parameter θ*. We further prove asymptotic normality and evaluate the corresponding asymptotic covariance. These results reveal interesting tradeoffs between the negative effect of "loss of information"" due to incorporation of the nonlinearity and the positive effect of communication noise reduction. We also demonstrate and quantify benefits of introducing the nonlinearity in high-noise (low signal-to-noise ratio) and heavy-tail communication noise regimes. © 2023 Society for Industrial and Applied Mathematics.
| Engineering controlled terms: | AdditivesParameter estimationStochastic systems |
|---|---|
| Engineering uncontrolled terms | Communication noiseConsensus + innovationsDistributed estimationDistributed inferenceGeneral classHeavy-tail noiseHeavy-tailsRecursive estimationStochastic approximationsVector parameter |
| Engineering main heading: | Signal to noise ratio |
| Funding sponsor | Funding number | Acronym |
|---|---|---|
| Ministarstvo Prosvete, Nauke i Tehnološkog Razvoja | MPNTR | |
| Horizon 2020 Framework Programme See opportunities by H2020 | 957337 | H2020 |
| Horizon 2020 | 871518 |
*Received by the editors February 10, 2022; accepted for publication (in revised form) January 9, 2023; published electronically June 20, 2023. https://doi.org/10.1137/22M1477015 Funding: The work of the first and third authors is supported by the European Union's Horizon 2020 Research and Innovation program under grant 957337. The work of the second author is supported by the European Union's Horizon 2020 Research and Innovation program under grant 871518. The work of the first three authors was also supported by the Serbian Ministry of Education, Science and Technological Development. \\dagger Faculty of Sciences, Department of Mathematics and Informatics, University of Novi Sad, Novi Sad, Serbia ([email protected]). \\ddagger Faculty of Technical Sciences, Department of Fundamental Sciences, University of Novi Sad, Novi Sad, Serbia ([email protected]). \\S Faculty of Technical Sciences, Department of Power, Electronic and Communication Engineering, University of Novi Sad ([email protected]). \\P Amazon Alexa AI, Seattle, WA 98109 USA ([email protected]). \\| Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA 15213-3890 USA ([email protected]).
The work of the first and third authors is supported by the European Union's Horizon 2020 Research and Innovation program under grant 957337. The work of the second author is supported by the European Union's Horizon 2020 Research and Innovation program under grant 871518. The work of the first three authors was also supported by the Serbian Ministry of Education, Science and Technological Development.
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