In this paper, the performance of a visible light communication (VLC) system based on offset pulse position modulation (Offset-PPM) has been demonstrated using a commercial high power white single LED (30 W) and the new coding scheme. Data at a speed of 11 Mbps has been successfully transmitted over a distance of 1 m with zero bit error rate (BER), and 18 Mbps with 1.15 × 10 of BER through the simplest transceiver circuits.Keywords-bit error rate; offset pulse position modulation; visible light communication.

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-In this paper a dicode pulse position modulation (DiPPM) technique has been successfully implemented for an indoor visible light communication (VLC) based system using an FPGA and a commercial high power white LED (30 W). A data rate of 13 Mbps has been achieved with a bit error rate (BER) <10 -11 at a free space distance of 1.2 m through a basic transceiver circuit, and 14.5 Mbps with 1.15x10 -6 of BER. Furthermore, a data rate of 13 Mbps has been successfully transmitted over a distance of 1.8 m with BER of 10 -5 . This proves that the application of DiPPM is a viable modulation system over free space communication links.

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Abstract-Low bandwidth expansion modulation schemes are preferred for free space and optical fibre data transmission, where limited bandwidth is available. One such scheme is duobinary pulse position modulation (DuoPPM), which is the subject of this paper. DuoPPM scheme is not as sensitive to bandwidth expansion issues as digital PPM, with a line rate of twice the data rate. This paper discusses first time practical implementation of DuoPPM coding scheme and its application in free space using visible light LED (30 W) for transmission purposes. Experimental results achieved at the data rate of 14 Mbit/s indicate an error rate that is better than 1 error in 10 9 . The main aim is to analyse the practicality, robustness and limitations of DuoPPM.