An SFBC-OFDM receiver with MLSE equalizer to combat multiple frequency offsets

Synchronization is an important issue arises when distributed multiple transmitters are deployed. Unlike conventional MIMO systems, cooperative transmitters may distribute geographically instead of co-locating at the same spot. Therefore, it is hard for the destination node to compensate multiple carrier frequency offsets (MCFOs) even if the cooperative transmitters use the same clock, and the conventional MIMO decoding strategy may not be suitable. In this paper, we consider cooperative SFBC-OFDM transmission with MCFOs. The proposed strategy carefully combines two sets of separately synchronized signal to mitigate inter-carrier interference (ICI). Maximum-likelihood sequence estimation (MLSE) and iterative interference cancellation is further deployed to improve performance. Simulation results show the diversity gain is maintained and an improved tolerance range of MCFOs is achieved.