Space time transmit site diversity for OFDM multi base station system

In a single frequency network (SFN) using OFDM, the signals from plural base stations cannot be combined coherently at the receiver and large diversity gain cannot be achieved. We consider a system using space time transmit diversity (STTD) for site diversity between base stations. The site diversity technique using STTD is used in each sub-carrier of OFDM. We call this technique space time transmit site diversity method. STTD is a transmit diversity technique based on space time block coding and this technique does not require to know the channel condition at the transmitter. Consequently, using computer simulation, we show that the proposed system can improve the performance compared with the conventional SFN.