  A subspace projection to improve channel estimation in massive multi-antenna
systems is proposed and analyzed. Together with power-controlled hand-off, it
can mitigate the pilot contamination problem without the need for coordination
among cells. The proposed method is blind in the sense that it does not require
pilot data to find the appropriate subspace. It is based on the theory of large
random matrices that predicts that the eigenvalue spectra of large sample
covariance matrices can asymptotically decompose into disjoint bulks as the
matrix size grows large. Random matrix and free probability theory are utilized
to predict under which system parameters such a bulk decomposition takes place.
Simulation results are provided to confirm that the proposed method outperforms
conventional linear channel estimation if bulk separation occurs.
