How imperfect orthogonality of pilot affects channel estimation and data recovery techniques in massive MIMO system

This paper analyzes the impact of imperfect orthogonality of pilot on channel estimation in Multiuser Massive MIMO system. There are K number of decentralized User Equipment (UE) having single antenna in the system and Base Station (BS) equipped with very large number of antennas. Ideally, pilot symbols are supposed to be orthogonal but due to interference, pilot symbols could not intact orthogonality and result in imperfect orthogonality. Thus, its effect is analyzed with a MMSE based Channel Estimation algorithm. Performance of channel estimation directly affects the performance of data recovery algorithm. Therefore, performance of data recovery is also investigated due to the estimated channel using imperfect orthogonal pilot symbol.