# Supporting Immersive Video Streaming via V2X Communication
## 2 Bandwidth Allocation for Diverse Streaming Services in V2X Communication
### Bandwidth Calculation Module for Vehicle Video Applications  
Once the vehicle passenger initiates the video streaming application, this module will obtain the video requirements and specifications from the application software provider's server based on the preset video quality. For VR applications such as 360-degree video and 6 DoF video, the vehicle uploads the head motion trajectory from the user's historical database to the server. This allows the software provider to predict the FoV of the requested video and return the requirements and specifications for the base layer and enhancement layer of the video. Notably, since the G-PCC encoder directly compresses 3D PtCl and cannot be enhanced using LCEVC technology, the server returns the video requirements and specifications without enhancing it into the base layer and enhancement layer if the video application type is a 6 DoF PtCl real-time application. The execution steps of this module are as follows:  
* When the vehicle passenger initiates the video streaming application, this module retrieves the video specifications from the video streaming application software provider's server. If the video type is a VR application, the user's historical head motion trajectory is uploaded to the server. This allows the server to predict the FoV and return the specifications required for the requested video's base layer and enhancement layer. * The estimated arrival times at each section of the route, along with the video application requirements and specifications, are uploaded to the RSUs along the route. Subsequently, this module requests the governing RSU over the current road segment to activate its \"Bandwidth Assignment Coordination\" module and awaits the results. * If the results received in the previous step indicate that the required bandwidth can be satisfied, proceed to the next step. Otherwise, proceed to Step 9 accordingly. * If the video quality adjustments have reached the system-set limit, proceed to Step 10; otherwise, continue with the execution. * If the video application type is not 6 DoF PtCl video, or if the system has reached its maximum allowable quantity of 6 DoF PtCl videos, proceed to Step 8. Otherwise, continue with the execution. * If the 6 DoF PtCl video is live video, increase the point density in the user's video according to the following equation and return to Step 2. Otherwise, continue to the next step. \[ \begin{split} upc^{R}_{t^{\prime,\pi}_{j}}=\left\{\frac{pc^{R}_{pl^{ \pi,\pi}+1}}{\overline{pl}^{\pi}}&\quad if\;ursu_{t^{\prime,\pi}_{ j}}>0,\;pl^{\pi,\pi}\leq\overline{pl}^{\pi},\;rt_{c^{\prime}_{t^{\prime}}}\leq t^{ \prime,\pi}_{j}\leq rt_{c^{\prime}_{t^{\prime}+1}},\;1\leq j\leq e^{\pi,\pi},1 \leq i<h^{\sigma}\\ &\quad\text{others}\end{split} \right.\end{split} \tag{9}\]  
\[ \begin{split} dpc^{R}_{t^{\prime,\pi}_{j}}=\left\{\frac{pc^{R}_{pl^ {\pi,\pi}+1}}{\overline{pl}^{\pi}}&\quad if\;dsu_{t^{\prime,\pi} _{j}}>0,\;pl^{\pi,\pi}\leq\overline{pl}^{\pi},\;rt_{c^{\prime}_{t^{\prime}}} \leq t^{\prime,\pi}_{j}\leq rt_{c^{\prime}_{t^{\prime}+1}},\;1\leq j\leq e^{ \pi,\pi},1\leq i<h^{\sigma}\\ &\quad\text{others}\end{split} \right.\end{split} \tag{10}\]  
where \(upc^{R}_{t^{\prime,\pi}_{j}}\) and \(dpc^{R}_{t^{\prime,\pi}_{j}}\) represent the point density uploaded and downloaded for 6 DoF live video by vehicle passenger \(\sigma\) at time \(t^{\prime,\pi}_{j}\), respectively. \(ursu_{t^{\prime,\pi}_{j}}\) and \(drsu_{t^{\prime,\pi}_{j}}\) respectively stand for the management RSUs where the upload and download bandwidths are insufficient for vehicle a during the period of passing through the segment connecting \(c^{\sigma}_{t}\) and \(c^{\sigma}_{t+1}\). \(t^{\sigma,\pi}_{1}\) and \(t^{\sigma,\pi}_{e^{\pi,\pi}}\) denote the current and ending times of \(\
u\), respectively. \(c^{\sigma}_{i}\) and \(c^{\sigma}_{i\
u}\) are the index values of the \(i\)-th intersection and the destination of the driving route.