Blind Unwrapping of Modulo Reduced Gaussian Vectors: Recovering MSBs From LSBs

We consider the problem of recovering n i.i.d. samples from a zero mean multivariate Gaussian distribution with an unknown covariance matrix, from their modulo wrapped measurements, i.e., measurements where each coordinate is reduced modulo Δ, for some Δ > 0. For this setup, which is motivated by quantization and analog-to-digital conversion, we develop a low-complexity iterative decoding algorithm. We show that if a benchmark informed decoder that knows the covariance matrix can recover each sample with small error probability, and n is large enough, the performance of the proposed blind recovery algorithm closely follows that of the informed one. We complement the analysis with numerical results that show that the algorithm performs well even in non-asymptotic conditions.