NONLINEARITY COMPENSATION IN OPTICAL COMMUNICATION SYSTEMS VIA ITERATIVE SIGNAL CLIPPING AND A MULTIPLE LED TRANSMITTER

摘要

The invention relates to optical indoor wireless, optical outdoor wireless, or optical fiber communication systems, in particular a system utilizing intensity modulated light emitting diode (LED) as a transmitter and a direct detection photodiode (PD) as an optical receiver. The invented iterative signal clipping (ISC) technique is based on iterative clipping of the time domain orthogonal frequency division multiplexing (OFDM) signal and transmission from a multiple LED transmitter. The LEDs are synchronized, located close to each other, and placed to emit light in the same direction. Hence, the channel path gains from each LED to the receiver PD are similar. The received signals from the different LEDs add coherently at the receiver. The effect of distortion due to clipping is eliminated or significantly reduced based on the considered number of LEDs.