Massive multiple input multiple output(MIMO) technology can support every
cell which has a base station (BS) with a large number of antennas and simultaneous use of the same resource. Therefore, Massive MIMO systems can give high
spectral (SE) and energy efciency (EE). However, in this technology, channel
estimation is one of the challenges that degrade the performance that need to
be addressed. In this work, we focus on the frst performance analysis of channel
estimation techniques for Massive MIMO in terms of computational complexity
and reliability. A practicable solution to solve the computational complexity and
reliability is to study the pilot-based channel estimators such as minimum mean
square error (MMSE), element-wise minimum mean square error (EW-MMSE),
and least square (LS) with their SE and EE. Time division duplex (TDD) protocol, spatial channel correlation, and multicell minimum mean square error
(M-MMSE) processing are also considered for reciprocity and pilot contamination
problems. We evaluate the performance of channel estimation techniques for the
Massive MIMO uplink system by using computational complexity, mean square
error (MSE), SE, and EE as performance metrics. The simulation results show
that pilot-based channel estimation has the lowest computational complexity and
the best reliability when compared to blind and semi-blind channel estimation
techniques. Moreover, MMSE estimators provided the lowest normalized MSE
and the highest achievable SE with the M-MMSE combining scheme