Research on Adaptive Cancellation of Inter-Carrier Interference in MIMO-OFDM

MIMO传输技术在正交频分复用系统中是非常有效的。然而，移动接收条件下的信道多普勒扩展对MIMO-ofdm系统的影响更为严重。在本研究中，提出了一种降低由于信道多普勒扩展而产生的载波间干扰的方案。在该方案中，使用基于多普勒扩展信道模型的导频符号来估计信道特性，并且使用估计的信道特性来减小载波间干扰的影响。此外，通过将预编码方案与MIMO传输相结合，可以进一步改善信道特性的影响。对于预编码方案的改进，还提出了迭代译码方案，使得提高性能和降低复杂度成为可能。通过仿真验证了该方案的性能。结果表明，该系统具有良好的性能。在进一步的研究中，提出了在更实际的接收情况下进一步提高性能的方案。并对硬件的简化进行了研究。

MIMO Transmission technique is very effective in OFDM systems. However, influence of channel Doppler spread under mobile reception is more severe in MIMO-OFDM. In this research, the scheme to reduce inter carrier interference generated by channel Doppler spread is. In this scheme, the channel characteristics is estimated using pilot symbols based on the Doppler spread channel model and influence of inter-carrier interference is reduced using the estimated channel characteristics. Moreover, by combining the pre-coding scheme with MIMO transmission, the influence of channel characteristics can be improved further. As for the improvement of pre-coding scheme, iterative decoding scheme is also prcposed and it made possible to improve performance and reduce complexily. The performance of the proposed scheme was examined by simulations. As the result, good performance was confirmed. In the further researches, the scheme to improve the performance further under more actual reception situations. And simplification of the hardware is also studied.