Pilot De-contamination by Modified HTRCI with Time-Domain CSI Separation for Two-cell MIMO Downlink

Abstract

This letter expands the previously proposed High Time Resolution Carrier Interferometry (HTRCI) to estimate a larger amount of channel status information (CSI). HTRCI is based on a comb-type pilot symbol on OFDM and CSI for null subcarriers are interpolated by time-domain signal processing. In order to utilize such null pilot subcarriers for increasing estimable CSI, they should generally be separated in frequency-domain prior to estimation and interpolation processes. The main proposal is its separation scheme in conjunction with the HTRCI treatment of the temporal domain. Its effectiveness is verified by a pilot de-contamination on downlink two-cell MIMO transmission scenario. Binary error rate (BER) performance can be improved in comparison to conventional HTRCI and zero padding (ZP) which replaces the impulse response alias with zeros.