Impact of different LED-spacing in arrayed LED transmitter on VLC channel modeling

For convenience of analysis, empirical transmitter simplification is often introduced into visible light communication (VLC) channel modeling. This simplification induced impact on channel characteristics needs to be comprehensively evaluated. This paper addresses the applicability of this simplification. Six transmitter configurations with increasing LED-spacing in a LED transmitter of fixed number of LED chips are covered. Simulation results indicate that even in limit case, the maximum deviation of optical path loss (OPL) and 3-dB transmission bandwidth for different cases is still less than 0.40 dBo and 1.38 MHz which is acceptable while respective spatial fluctuation lies within 55.60-58.38 dBo and 19.38-23.96 MHz. On the other hand, the impact on the root mean square (RMS) delay spread is up to prominent 1.67 ns considering the actual level of 2.00-3.35 ns. In this aspect, there is observable spatial distribution difference between simplification case and original configuration case.