Patent ID: 8811826

Claim:
A method for transmitting data by means of a plurality of light emitting diodes, comprising the steps of: grouping the light emitting diodes into plurality of groups; assigning a unique subset of the light emitting diode groups to each of a plurality of different n-bit data values; transmitting a sequence of n-bit data values by: for each n-bit data value: identifying the subset of light emitting diode groups assigned to that n-bit data value, and transmitting the n-bit data value by a collective modulation, comprising a collective increase or decrease, of an intensity emitted by the light emitting diodes of the identified subset of light emitting diode groups; and wherein for each n-bit data value, the collective intensity modulation for transmitting that data value is performed between non-data-transmission periods having longer durations than that of the collective intensity modulation, wherein the light emitting diodes are not modulated during the non-data-transmission periods, and wherein the emitted intensity of the plurality of light emitting diodes during the transmission of each data value is greater than or less than the emitted intensity of the plurality of light emitting diodes during non-data-transmission periods; and periodically varying the assignments of the subsets of the light emitting diode groups corresponding to the different n-bit data values.