During the indoor visible light communication (VLC) channel modeling proce-22 dure, the transmitter constituted by an array of light-emitting diodes (LED's) is frequently 23 modeled as a single point source for convenience. However, how accurate this simplified 24 treatment is remains unanswered. This paper compares the channel characteristics of 25 both the simplified point-source model and six practical cases having various numbers of 26 LEDs. Our numerical results show that the deviations in

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... terms of the channel's optical 27 path loss (OPL), as well as its bandwidth and the channel's delay spread, are steadily in-28 creased upon increasing the number of LEDs of each transmitter, until LEDs spread al-29 most over the entire ceiling. Even in the worst case, the deviation of the OPL 30 remains below 0.41 dBo, whereas that of the 3-dB transmission bandwidth is below 1. 31 67 MHz. However, the deviation in terms of the root-mean-square (RMS) delay spread 32 can reach 1.88 ns. Moreover, in terms of spatial distribution of the RMS delay spread, 33 there is a nonnegligible difference between the simplified point-source model and differ-34 ent transmitter configurations. 35 Index Terms: Visible light communication, channel characterization, modeling accuracy, 36 point-source model. 37 42 ment in various indoor VLC systems in order to improve their performance [5]-[7]. As a critical 43 component, the VLC channel model is expected to reliably capture the multipath propagation 44