# Supporting Immersive Video Streaming via V2X Communication
## 2 Bandwidth Allocation for Diverse Streaming Services in V2X Communication
### Route Planning and Adjustment Module for Vehicles  
Before departure, vehicle passengers use the app installed in the vehicle to activate this module, planning the shortest driving route with instant traffic updates from the cloud. The system calculates the optimal route based on current traffic conditions and historical data, aiming to reach the destination in the shortest possible time. During the journey, this  
Figure 2: Diagram of Bandwidth Allocation for Video Applications in a Cell-Free In-Vehicle Network Architecture. module continuously monitors real-time traffic conditions and dynamically adjusts the route based on real-time changes. For instance, if a traffic accident, road construction, or other unforeseen events occur ahead, the system will immediately recalculate an alternative route to help the passenger avoid congested or hazardous road sections. Simultaneously, this module periodically estimates the travel time for subsequent segments and makes predictions based on actual driving conditions. If the vehicle passenger changes plan, such as adding a stop or changing the destination, the system will replan the route and estimated arrival time based on the new requirements. Additionally, if the estimated time of arrival for road sections differs significantly from the original schedule, this module will recalculate the shortest driving route and arrival time, making timely adjustments as needed. To ensure that RSUs obtain the latest traffic information, this module will send updated relevant information to the RSUs along the route. This information includes the times the vehicle passes through each section and the current traffic conditions. Upon receiving this information, the RSUs will update their databases, providing other vehicles with more accurate traffic information and road condition forecasts. The execution steps of this module are as follows:  
1. Before the vehicle departs, real-time traffic information is retrieved from the cloud. Based on the destination set by the vehicle passenger and the average travel time returned by each segment RSU, the shortest driving route is selected using the Dijkstra algorithm as follows: \[\mathbf{R}^{\sigma}=\left(c_{1}^{\sigma},c_{2}^{\sigma},\cdots,c_{\mathit{l}^ {\sigma}-1}^{\sigma},c_{\mathit{l}^{\sigma}}^{\sigma}\right),\] (1) where \(c_{1}^{\sigma}\) and \(c_{\mathit{l}^{\sigma}}^{\sigma}\) represent the starting point and the final destination of the driving route for vehicle \(\sigma\), respectively. 2. The following equations are used to calculate the time for the vehicle to arrive at each road section and transmit the estimated time to the RSU along the route: \[\mathit{rt}_{c_{i+1}^{\sigma}}=\mathit{rt}_{c_{i}^{\sigma}}+RD_{c_{i}^{ \sigma},c_{i+1}^{\sigma}}\Big{(}\mathit{rt}_{c_{i}^{\sigma}}\Big{)}+ID_{c_{i}^ {\sigma},c_{i+1}^{\sigma}}\Big{(}\mathit{rt}_{c_{i}^{\sigma}}\Big{)},\;1\leq i <\mathit{h}^{\sigma}\;,\] (2) \[\mathit{rt}_{c_{1}^{\sigma}}=\mathit{C}\mathit{urTime}\] (3) where \(c_{i}^{\sigma}\) represents the \(i\)-th intersection that vehicle \(\sigma\) passes through, and \(\mathit{CurTime}\) is the current time. \(RD_{c_{i}^{\sigma},c_{i+1}^{\sigma}}\Big{(}\mathit{rt}_{c_{i}^{\sigma}}\Big{)}\) denotes the time it takes for the vehicle to pass through the segment connecting \(c_{i}^{\sigma}\) and \(c_{i+1}^{\sigma}\) after arriving at road section \(c_{i}^{\sigma}\) at time \(\mathit{rt}_{c_{i}^{\sigma}}\), while \(ID_{c_{i}^{\sigma},c_{i+1}^{\sigma}}\Big{(}\mathit{rt}_{c_{i}^{\sigma}}\Big{)}\) stands for the time spent by the vehicle due to traffic control before entering the segment connecting \(c_{i}^{\sigma}\) and \(c_{i+1}^{\sigma}\) after arriving at road section \(c_{i}^{\sigma}\) at time \(\mathit{rt}_{c_{i}^{\sigma}}\). Here, the values of \(RD_{c_{i}^{\sigma},c_{i+1}^{\sigma}}(\cdot)\) and \(ID_{c_{i}^{\sigma},c_{i+1}^{\sigma}}(\cdot)\) are both predicted using Support Vector Regressions. 3. This module operates in the background execution mode. 4.