Joint frequency offset estimation and interference cancellation for MIMO-OFDM systems [mobile radio]

Synchronization and equalization in wireless multi-user MIMO-OFDM (multiple-input multiple-output orthogonal frequency division multiplexing) systems is important for next generation wireless communication. This paper proposes a new algorithm for joint frequency offset estimation and equalizer training for the uplink of a multi-user MIMO-OFDM system where each user employs spatial multiplexing. A new two-stage receiver structure is adopted, which consists of an initial space-time equalization for suppressing the co-channel interference (CCI), shortening the channel, and mitigating asynchronicity, followed by parallel equalization and detection in the frequency domain. The effects of frequency offset for each transmit data stream can be adjusted after the space-time equalization. Simulations show good performance in terms of bit error rate and mean square error for the frequency offset estimation.