提出基于空时块码(STBC)调制的自适应多输入多输出正交频分复用（MIMO-OFDM）可见光通信(VLC)系统, 该系统能够克服MIMO信道相关性并实现可靠通信。同时, 引入功率比特分配(PBA)与OFDM相结合, 以适应信道传输条件从而有效提高频谱效率。通过搭建一个2×2的MIMO-OFDM VLC演示系统, 实现了80 cm距离的传输, 实验中测得的误码率始终保持在7%的前向纠错阈值3.8×10-3之下。实验结果表明, STBC MIMO-OFDM系统对MIMO信道相关性鲁棒, 且PBA的应用能够大幅度提高数据速率。

An adaptive multiple-input multiple-output orthogonal frequency division multiplexing(MIMO-OFDM) visible light communication(VLC) system based on space-time block coding (STBC) modulation was proposed in the paper, which can overcome the MIMO channel correlation and achieve reliable communications. Meanwhile, power-and-bit allocation(PBA) was combined with OFDM in order to adapt to the channel and improve the spectral efficiency. Then a 2×2 MIMO-OFDM VLC transmission over a distance of 80 cm was demonstrated, where the measured bit error rates were all below 7% of the pre-forward-error-correction threshold of 3.8×10-3. Experimental results show that the STBC MIMO-OFDM system is robust to MIMO channel correlation, where the data rates can be greatly improved by applying the PBA.