This document discusses optical spatial modulation OFDM using micro LEDs. It begins with introducing OFDM, visible light communication, MIMO systems, and optical spatial modulation. It then explains how OSM-OFDM can be implemented using micro LEDs to achieve high data rates up to 5.5 Gb/s with lower complexity compared to optical spatial multiplexing. The bit error rate depends on the spatial separation between transmitters and the semi-angle of the micro LEDs. Larger separation and smaller semi-angle provide optimum conditions.