An equalization technique for distributed stbc-ofdm system with multiple carrier frequency offsets

In this paper, we investigate the performance of distributed space-time block coded (DSTBC) orthogonal frequency-division multiplexing (OFDM) system (DSTBC-OFDM) with the presence of carrier frequency offsets. Since the transmit antennas belong to different nodes that are distributed, there may exist multiple carrier frequency offsets to the transmitters at the receiver of DSTBC-OFDM system. Received signal model of DSTBC-OFDM system with multiple carrier frequency offsets is given. Then a frequency-domain equalization technique is proposed to mitigate the inter-carrier interference (ICI) and the inter-symbol interference (ISI) when detecting the symbols. The proposed equalizer has a reasonable performance and low computational complexity. Simulation results show that the equalization technique is quite effective when the carrier frequency difference between the distributed transmitters is small, and moreover, by setting the receiver´s frequency to the mean value of the transmitters´ frequencies, a better performance can be obtained