Visible light communication apparatus capable of minute dimming control and method using the same

A visible light communication apparatus, comprising:

• a dimming level determination unit for determining a dimming level variable to perform minute dimming control;
• a dimming symbol selection unit for selecting an upper dimming symbol and a lower dimming symbol, which belong to VPPM symbols, based on the dimming level variable;
• a unit for calculating the number of symbols to be sent, the unit for calculating the number of symbols to be sent being configured to determine at least one of a number of upper dimming symbols to be sent and a number of lower dimming symbols to be sent based on the dimming level variable;
• and
• a signal generator for generating a transmission sequence corresponding to the dimming level variable by combining the upper dimming symbols and the lower dimming symbols based on the number of symbols to be sent,
• wherein the VPPM symbols comprise:
• a VPPM symbol corresponding to a state in which a light source is completely turned off;
• a VPPM symbol corresponding to a state in which a light source is completely turned on;
• and
• nine VPPM symbols corresponding to nine VPPM duty cycles which vary from 0.1 to 0.9 in increments of 0.1, and having VPPM symbol indices which are natural numbers ranging from 1 to 9
• wherein the signal generator is configured to:
• allocate data symbols to a number of lower dimming symbols equal to the number of lower dimming symbols to be sent;
• allocate data symbols to a number of upper dimming symbols equal to the number of upper dimming symbols to be sent;
• and
• if data symbols to be transmitted are not divided by 100, allocate VPPM idle pattern symbols to the lower dimming symbols or upper dimming symbols so that the transmission sequence is to be divided by 100.