Symbol detection method of DCO-OFDM (Direct Current Offset-Orthogonal frequency Division Multiplexing) system

The invention discloses a symbol detection method of a DCO-OFDM (Direct Current Offset-Orthogonal frequency Division Multiplexing) system, belonging to the field of visible light wireless communication. The method is carried out according to the following steps of firstly, preprocessing a received symbol r(n) to obtain an estimated value x(clip)n of a clipped sending signal; secondly, reconstructing clipping noise c(n) and subtracting the clipping noise from the signal x(clip)n to obtain an estimated value x(clip)n of an unclipped sending signal; thirdly, carrying out frequency domain conversion and symbol judgment operation on the x(n), and reconstructing the clipping noise c(n) by utilizing a judged symbol; fourthly, repeating the steps to reach a preset number of iterations; and lastly, demodulating the judged symbol to restore transmitted bits. According to the symbol detection method provided by the invention, the negative effect of the clipping noise on the detection performance can be reduced, an effective signal to noise ratio of a receiving signal is increased, in comparison with the conventional symbol detection method, the better detection performance can be obtained. Meanwhile, the method provided by the invention only needs simple symbol taking operation and DFT/IDFT (Discrete Fourier Transform/Inverse Discrete Fourier Transform) operation and has the advantages of small calculated amount and easiness in implementation.