Intensity Modulation and Direct Detection (IM/DD) is a traditional technique commonly used in Optical Wireless Communication (OWC) systems. However, this detection technique being non-coherent, either partially or completely, suppresses the negative data segment resulting in signal distortions. Flip-OFDM handles the constraints of IM/DD in OWC systems. The conventional receivers for flip-OFDM subtracts the negative data segment from the positive segment. As the noise variance increases, the receiver performance degrades. The iterative receiver is a new receiver structure introduced for flip-OFDM systems where the negative signal segment is concatenated to the positive segment. The technique estimates transmitted data, which ensures an optimum detection receiver performance. This technique is implemented for QAM (16, 64, and 256), BPSK and QPSK modulation schemes and the results for Line-Of-Sight (LOS), Non Line-Of-Sight (NLOS) and Stanford University Interim (SUI) channels are produced. Simulations prove that the iterative receiver provided SNR improvement over a conventional receiver.
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