Adaptive pilot decontamination in multi-cell massive MIMO networks

This paper considers the contaminated channel estimation in multicell very large multiuser multiple-input multiple-output networks. To provide desirable spectral efficiency of these systems, we propose two adaptive algorithms which their implementations do not require orthogonal pilot sequences. The first algorithm (i.e., normalized least mean square) has low complexity and also gives an acceptable spectral efficiency in channels with low attenuation. The second algorithm (i.e., recursive least square) is more robust against pilot contamination and provides the desirable spectral efficiency in very large number of antennas at the base stations. In simulations, the performance of the proposed algorithms is evaluated and also compared with the performance of the conventional minimum mean square error estimation.