Iterative Receiver for Flip-OFDM in Optical Wireless Communication

To guarantee nonnegative signals in optical wireless communication systems, flipped orthogonal frequency division multiplexing (Flip-OFDM) transmits the positive and negative parts of the signal over two consecutive OFDM subframes (positive subframe and negative subfame, respectively). The conventional receiver for Flip-OFDM recovers the data by subtracting the negative subframe from the positive one. However, the signal analysis shows that the signals in the two subframes contain the information of the transmitted data and can be used together to decode the data. An iterative receiver is then proposed to improve the transmission performance of Flip-OFDM by exploiting the signals in both subframes. Simulation results show that the proposed iterative receiver provides significant signal-to-noise ratio gain over the conventional receiver. Moreover, the iterative receiver also outperforms the existing advanced receiver.