## 3 Numerical Evaluation
### Effect of Azimuth Rotation  
Finally, the effect of beam azimuth direction for the integrated PLC and VLC transmission channel was investigated. Intuitively, the baseline Lambertian emission beam and the Rebel non-Lambertian emission beam are omnidirectional and symmetric, therefore any manipulated azimuth rotation to the ceiling-mounted LED optical source will not induce variation to the received signal strength for any position on the working plane of the receiver. On the contrary, the NSPW non-Lambertian optical beam is not omnidirectional or symmetric anymore, and could provide apparent spatial azimuth selectivity. For the convenience of the discussion, the projection of the wide side cross-section of this typical rotating asymmetric beam on the ceiling plane was utilized to indicate the original horizontal azimuth orientation. When the additional horizontal azimuth rotation is introduced to the asymmetric LED beam, the transmission performance of this hybrid channel will be differentially varied according to the spatial position of the individual receiver. In Figure 6, a comparison of the achievable rates versus the azimuth rotation angle is illustrated. Since the NSPW non-Lambertian optical beam can match the axisymmetric emission pattern around the normal axis of the LED, the specific spatial beam radiation, manipulated by the horizontal azimuth rotation of 180\({}^{\circ}\), can perfectly overlap with the initial spatial beam radiation without any horizontal azimuth rotation. Based on this rotation periodicity, the discussed range of horizontal azimuth rotation was between 0\({}^{\circ}\) and 180\({}^{\circ}\). As is shown in Figure 6, the effect of the above horizontal azimuth rotation on the superior channel transmission performance of the central receiver position, was attributable to its dependence on the horizontal azimuth rotation on the axis direction of the LED source. Nevertheless, for the side position, the respective achievable rate is significantly affected by the azimuth rotation angle. Up to 37.7 Mbps of rate gain can be obtained by a 90\({}^{\circ}\) horizontal azimuth rotation, which makes the asymmetric beam horizontally oriented to the side position. At the same time, for the side position 2, the 90\({}^{\circ}\) horizontal azimuth rotation led to about 37.7 Mbps of rate loss from the original achievable transmission performance of almost 136.6 Mbps, due to the orthogonal orientation of horizontal beam with respect to the candidate receiver position. As for the corner position, a similar phenomena can be observed when the azimuth rotation is up to about 30\({}^{\circ}\) or 60\({}^{\circ}\), as the relevant achievable rate is increased to about 96.6 Mbps from the initial 75.4 Mbps.  
As for the 6G aspect, actually, various popular VLC styles, including hybrid PLC and VLC, are being actively explored in multiple typical application scenarios as one important technique for enabling the future-oriented LED infrastructure-based 6G IoT Network. It must be noted that the coming 6G IoT Network must face the distinct LED infrastructures with customized designs for various lighting targets, but LED infrastructures with conventional Lambertian beam configurations are not well discussed. Therefore, as the main contribution of this work, research on the channel characteristics of hybrid PLC and VLC based on distinct optical beam configurations is essential and fundamental for paving the way to applying VLC, especially hybrid PLC and VLC, in the coming 6G IoT Network.