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On channel estimation for massive MIMO with pilot contamination and multipath fading channels

This paper introduces a simple and practical channel estimator for multipath multi-cell massive MIMO TDD systems with pilot contamination. Least squares (LS) channel estimators present low performance under moderate to strong pilot contamination, while minimum mean square error (MMSE) estimators perform much better than LS estimators in such conditions. However, MMSE estimators present an issue that prevents its adoption in practical systems, namely the assumption there is perfect knowledge of the cross-cell large scale coefficients. The proposed estimator does not present any of the issues mentioned above and additionally provides performance that improves as the number of paths of the channels increases, reaching that of the MMSE estimator.