Optical wireless communication techniques are described and claimed. In one embodiment, the disclosure relates to method and apparatus to provide optical signaling with visible light having variable pulse position modulation (VPPM). The optical signal includes a Start Frame Delimiter (SFD) which indicates beginning of an asynchronous optical signaling. The VPPM signaling includes a lower frequency time varying amplitude component that when subsampled by a low frame rate camera results in alias induced flicker or blinking. Such signals are quickly recognizable as signals with modulated data. In another embodiment, the disclosure provides a system, device and method for decoding a Start Frame Delimiter (SFD) to indicate arrival of incoming VPPM optical data.