Biorthogonal DSSS for infrared wireless communications on non-Lambert reflection channels

For optical wireless networking, it is desirable to employ nondirected links whose performance depends on the reflection characteristics of the indoor surfaces. The non-Lambert reflection pattern, Phong model, is considered in the calculation of the multipath impulse response function as well as Lambert reflection pattern. The bit error rate (BER) of the optical wireless direct-sequence spread spectrum (DSSS) system using biorthogonal Walsh codes is investigated on a non-Lambert reflection channel. Simulation results demonstrate that biorthogonal DSSS systems can combat multipath dispersion with small power penalties very well. And by comparison, we show how much the error of the performance prediction for the biorthogonal DSSS system will occur when using Lamertian approximation on the non-Lambert channel.