Symbol Rate and Timing Estimation for Image-Sensor VLC by a Cycle Pattern of Received Symbols

In order to achieve symbol synchronization at an arbitrary symbol rate in the image-sensor visible light communication (VLC), an estimation method for both symbol rate and timing for the symbol synchronization is proposed and experimentally investigated. The estimation method based on cycle pattern characteristics of the received symbols enables the estimation of both the symbol rate and timing for the symbol synchronization at an arbitrary symbol rate less than the frame rate. In 30-frames-per-second (fps) image sensor, the symbol synchronization was achieved up to 27.8 symbols per second (sps) at intervals of 0.1 sps by simultaneous estimation of the symbol rate and timing. Moreover, when the symbol rate is known, the sequential estimation method is successfully applied to the symbol timing estimation to reduce the number of symbols required for the synchronization. The sequential estimation method enables the symbol timing estimation up to higher symbol rates as the number of symbols required for the synchronization increases.