A Novel Direct Sequence Spread Spectrum-based TDMA VLC Network in Open Light Field

Visible light communication (VLC) has been considered as a promising technology for indoor high-speed and low-latency communication services. Although transmitter lens is usually required to enhance the transmission rate and distance, this approach hinders the uniformity of indoor illumination and the mobility of communication in a practical VLC scenario. Thus, it is compelling necessity to investigate the VLC network without transmitter lens. However, due to severe attenuation of the channel and inescapable noise interference of the photoelectric conversion device, the signal-to-noise ratio (SNR) at the receiver tends to be low in the open light field. To address this issue, a novel direct sequence spread spectrum (DSSS)based time division multiple access (TDMA) VLC network with time-frequency synchronization scheme is proposed to reduce the signal power requirement and enhance the anti-interference capacity. Moreover, an experimental VLC test-bed in open light field is constructed to verify the efficiency of the proposed scheme. The experimental results demonstrate that the VLC test-bed with only 3 W LED transmit power can support smooth transmission of 720p high definition multimedia in indoor environment.