ABSTRACT

ABSTRACT: With the demand for high speed data transmission and rapid growth of end users, massive Multiple-Input Multiple-Output (MIMO) has shown to be promising owing to its high spectrum efficiency. Uplink pilot contamination is the main performance bottleneck of a large-scale MIMO multicell multi-user TDD system. Channel estimation suffers from pilot contamination because of the shortage of orthogonal sequences. Orthogonal pilot sequences are used in one cell but the same pilot sequences must be reused in neighboring cells, which causes pilot contamination. In this paper, pilot sequence hopping is performed at each transmission slot, which provides a randomization of pilot contamination. Applying the blind equalization technique, it is shown that such randomized contamination can be significantly suppressed. Numerical results show that the channel estimation accuracy improved.