OFDM Techniques for VLC Environment

        OFDM Stand for “Orthogonal Frequency Division Multiplexing” that is used by the VLC (Visible Light Communication) system which decrease an impact of the inter symbols with the interferences. During several cases, a significant problem is the OFDM-based for VLC systems is the high PAPRS (peak to average power ratios) (Chen 2017).Normally the VLC systems is consists of three parts , transmitter, receivers as well as channels as shown in below figure

A simulation code in MATLAB is desired for the comparison of OFDM techniques for VLC in indoor environments.

OFDM systems used the Viterbi that is the channel decoder on the behalf of the VLC systems. The OFDM has the advantage over a conventional wireless for the communication systems due to the efficiency of the bandwidth. ODFM is used for the multicarrier of the transmit data for the high speed (Adiono and et.al 2017).

Now the MATALB simulation of the OFDM, covers the transmitter OFDM as well as OFDM of receivers that is the basic chain coded in the MATALB. First of presents the OFDM transmitters.

Now the below MTALAB Code is the BER in OFDM systems that the modulation of the 16 QAM.

The techniques to be compared and analyzed are: DCO-OFDM, ACO-OFDM and ADO-OFDM.

        The DC bias is added in the signal for the making it positives in the DCO-OFDM .And in the DCO-OFDM the bias is added in the signals that make it positives. In the average optical power for a constellations like the 4QAM, 16-QAM, as well as 64-QAM the DCO-OFDM is the less efficient as compare to the ACO-OFDM. But in the larger constellations the DCO-OFDM is more efficient because the DC bias is used in the DCO-OFDM (Dissanayake 2013).

        Through the clipping of the original bipolar OFDM the transmitted signal is created it positives where the signal is zero as well as its transmitting the positives parts. The odd subcarriers that transmit the data in the ACO-OFDM. ACO-OFDM is utilized for the identification of the samples that is received the signals which is likely the addition of Nosie. During the diversity of the combining systems for the ACO-OFDM is presented the nonlinear processing’s that the signal received form the even sub-carriers. Now in this section the comparison of the ACO-OFDM, ADO-OFDM, as well as DCO-OFDM is explained. The odd Subcarrier is used in the ADO-OFDM and in the ACO-OFDM, along with the even subcarriers is used in the DCO-OFDM.

A functional simulation code is needed, with comments on the lines of code.

First the OFDM simulation given the coding of the transmitter as shown in below code

References of Ofdm Techniques for Vlc Environment

Adiono, Trio , and et.al. 2017. "Design of an OFDM System for VLC with a Viterbi Decoder." IEIE Transactions on Smart Processing and Computing 6 (6).

Chen, Jian . 2017. "A channel model for indoor visible light communication system with specular reflection." 16 International Conference on Optical Communications and Networks (ICOCN).

Dissanayake, Sarangi Devasmitha . 2013. "Comparison of ACO-OFDM, DCO-OFDM and ADO-OFDM in IM/DD Systems." Journal of Lightwave Technology 31 (7): 1063–1072.