The Improved Frequency Synchronization Estimator For MIMO-OFDM

Orthogonal Frequency Division Multiplexing (OFDM) is a promising technology for its robustness to selective fading and high spectral efficiency. Multi-Input Milti-Output (MIMO) technology, which has multi tansmittors and multi receivers, can achieve high throughput. So MIMO-OFDM technology now becomes the key technology for the next generation mobile communication system. However OFDM system is very sensitive to carrier frequency offset. So it is very important to have a good estimator for the frequency synchronization technology.In this paper, we research the frequency synchronization technology of the MIMO-OFDM system. And we propose a new estimation approach for the MIMO-OFDM system. This is a pilot based method which applies the transmission of a know data sequence to estimate carrier frequency offset as SISO-OFDM systems. And the new approach will be more efficient than to estimate carrier frequency offset of each path individually using the traditional estimator.Even though the new method is a possible efficient way for the carrier frequency offset estimation of and MIMO-OFDM system. There are still some areas for future research and improvements. There is a possibility to increase more concurrent transmissions. And then it is worthwhile to study its performance in an OFDMA system. For a true multiple access system, such as OFDMA system, full spectrum is partitioned into serveral groups for different users to communicate concurrently.