| （英） |
Recently, underwater visible light communications (UVLC) have been attracted much attention for searching and excavating under sea resources effectively. While, the UVLC suffers from back-ground noise from sunlight, the application of UVLC has been limited to the deep ocean. In order to realize the UVLC in shallow water, UVLC with maximal-ratio combining scheme applied to angle diversity receiver with multiple PDs at different angles was proposed and, in particular, the optimization of PD placement has been studied. However, as the field of view (FOV: field of view) of each PD was fixed at 90 degrees, its optimization has not been studied. Therefore, this paper investigates the optimal FOV of PDs that maximize the average SNR of a square communication area of $rm{r}^2[rm{m}^2]$ centered at 4 different PDs arrangement type of receivers. As a result, in an area of r=4m, narrowing the FOV of the receiver with evenly distributed PDs to 25 degrees improved the average SNR by about 3 dB compared to the case where the FOV was set to 90 degrees. In the r=16m area, narrowing the FOV of the receiver with PDs placed on the sides to 75 degrees improved the average SNR by about 0.8 dB compared to the case where the FOV was set to 90 degrees. |