Symbol Error Rate Calculation for Alamouti Space Time Coded OFDM in Direct Conversion Receivers

In this paper we present an analytical approach to evaluate the M-QAM symbol error rate (SER) of Alamouti space time coded OFDM direct conversion receivers subject to carrier frequency offset (CFO), channel estimation errors, outdated channel state information and flat receiver I/Q imbalance in Rayleigh time and frequency selective fading channels. Based on correct modeling of the correlation between channel estimates and received signals with carrier frequency offset and receiver I/Q imbalance, the SER can be numerically evaluated by averaging symbol error rates on different subcarriers using an analytical expression of double integrals. The results illustrate that the analysis can approximate the simulative performance very accurately if the power delay profile of fading channels, the receiver I/Q imbalance parameters and carrier frequency offset are known.