Patent ID: 9264138
Filing Date: 2016-02-16
CPC Classification: H04B,H04L

Claim Text:
1. A method, comprising: detecting, using a first visible light system, an amount of light received during first and second dark slots of a predefined synchronization pattern; comparing the amount of light received during the first dark slot to the amount of light received during the second dark slot; adjusting, based on the comparison, a clock in the first visible light system such that the first and second dark slots align with corresponding dark slots of a second visible light system, wherein the first and second visible light systems use the same synchronization pattern; emitting light from a light source of the first visible light system during an energy slot in the predefined synchronization pattern, wherein respective time periods of the first and second dark slots and energy slot are set to mitigate an ability of a human eye to detect a change from one of the first and second dark slots to the energy slot in the predefined synchronization pattern; and after adjusting the clock of the first visible light system, transmitting a predefined start frame delimiter (SFD) preamble, wherein the SFD preamble is configured to maintain the synchronization between the first and second visible light systems, wherein the second visible light system is configured to record the data received during the corresponding dark slots in a data window and evaluate the data window to determine if the first visible light system is transmitting the SFD preamble.