Performance Analysis for Channel Estimation Based on Common Pilot and User-Specific Pilot Schemes

In this paper, we describe the guideline for pilot design with the common pilot scheme and the user-specific pilot scheme. Here, channels for estimation with the common pilot scheme are non-precoded channels and channels with the user-specific pilot scheme are precoded channels in multiple input multiple output (MIMO) systems. Both two pilot schemes are included in the standards because two pilot schemes are used for different requirements. The analysis for frequency selectivity of channels presents that pilot sub carriers of the user-specific pilot scheme are densely allocated in the frequency domain, compared with the common pilot scheme.