On Training Signal Design for Multi-User MIMO-OFDM: Performance Analysis and Tradeoffs

This paper addresses spectrally-efficient multiantenna multi-carrier uplink transmission scenarios where the users overlap in time and frequency and are separated using spatial processing at the base station. The robustness of the proposed training sequences to residual carrier frequency offset and phase noise is evaluated analytically. This analysis reveals an interesting design tradeoff between the Peak-to-Average Power Ratio of a training sequence and the increase in channel estimation mean squared error over the ideal case when these two impairments are not present.