Performance investigation of STBC-OFDM systems with frequency offset and a semi-blind approach for the correction

The paper studies the degradation caused by frequency offset in space-time block coded orthogonal frequency division multiplexing (STBC-OFDM) systems. The probability of error for such a system has been derived and it can be observed that frequency offset plays a significant role in the deterioration of system performance by introducing intercarrier interference (ICI). The paper proposes a two-stage semi-blind scheme to estimate the frequency offset accurately and correct it. The main idea is to construct some special pilot symbols exploiting the algebraic properties of STBC. Only a few training symbols are required during the initialization stage and the frequency offset estimation is carried on recursively. Therefore, the system rate is only slightly affected in contrast to other existing data-aided approaches.