Improved noise rejection receiver model for indoor optical wireless systems using wavelet de-noising technique

In this paper, a system model for indoor optical systems using direct modulated multiple transmitters and a single receiver, having the special feature of wavelet de-noising technique, is proposed. Wavelet techniques are used to isolate features of the received signal that are less prone to corruption by noise and ISI. This is expected to improve the overall performance of the system. The proposed model was simulated using MATLAB 6.5^®. In our simulation, the artificial, ambient and all other noise sources are modeled as additive white Gaussian noise. The simulation results show that the wavelet techniques offer a 5-6 dB improvement in the SNR compared to a simple thresholding scheme. We have also investigated the effect of a different wavelet basis in the proposed model. We have found that the biorthogonal 3.1 is the best one.