# Faudistic Platooning: Subdivide Platoons, Unite Networks, and Conquer Efficiency and Reliability
## 6 Conclusions  
We proposed _Feudalistic Platooning_, an extensive platooning concept that assigns roles to the vehicles of a platoon. According to these roles, vehicles reduce network load and steer communication flow within a platoon. Communication relies on two or more different networks. In the elaborated simulation scenario, we combined an ad hoc network (IEEE 802.11p) and cellular networks (LTE and C-V2X). We demonstrated that _Feudalistic Platooning_ adds a low additional load only, while relieving each individual network. It adds redundancy on crucial platoon data, improves operability by ensuring operation outside of \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline
**Publication** & **Communication** & **Key Contribution** & **Open Questions** \\ \hline A Predictive Framework for Dynamic Heavy-Duty Vehicle Platoon Coordination [42]. Year: 2019. & Single network: (i) Cellular—central server. & Platoon coordination system on strategic layer within four-layered control architecture for platooning: (i) Service—good flows matched vehicles and drivers; (ii) Strategic—match making (i.e., transport layer); (iii) Tactical—platoon management and maneuvers (i.e., platoon layer); (iv) Operational—vehicle controller (i.e., vehicle layer). & (i) Tactical and operational layers; (ii) Connection loss: out of coverage and handover; (iii) Surrounding traffic. \\ \hline
3 GPP C-V2X and IEEE Vehicle-to-Vehicle Mode-4; (ii) IEEE 802.11p. & Single network—one of the two networks: (i) C-V2X Mode-3 or Mode-4; (ii) IEEE 802.11p. & Vehicle Layer: (i) Investigate the suitability of IEEE 802.11p and C-V2X for platooning according to following performance metrics: inter-vehicle distance, message latency, and PRR; (ii) Results show that traffic density leads to congestion on the radio channel. Suitability for platooning in descending order—C-V2X Mode-3, C-V2X Mode-4, and IEEE 802.11p. & (i) Heterogeneous platoon; (ii) Cellular handover; (iii) No communication flow—broadcast/multicast or retransmission required; (iv) Time-varying traffic density. \\ \hline Cloud-Assisted Distributed Control System Architecture for Platooning [44] & Single network: (i) Cellular—5G. & Three-layered distributed functional architecture to control and manage platoons assisted by cloud computing platform: (i) Trip planner (cloud); (ii) Road section manager (edge); (iii) Coordination control (vehicle). & (i) Connection loss: out of coverage and handover. \\ Platooning on the edge [45] Year: 2020 & Single network: (i) Cellular—4G/5G. & (ii) Road section manager (edge); (iii) Coordination control (vehicle). & (iii) Other layers and their impact on the delay and packet loss; (i) Connection loss: out of coverage and handover; (iii) Surrounding traffic; (iv) Varying data dependency. \\ \hline Towards Edge Intelligence in the Automotive Scenario: A Discourse on Architecture for Database-Supported Autonomous Platooning [46] Year: 2022 & Single network: (i) Vehicular dynamic spectrum access. & Vehicle layer: (i) Dynamic selection of the operating frequency for intra-platoon communication with the aim to minimize overall interference; (ii) Selection is supported by infrastructure (centralized, distributed, and hybrid); (iii) Unoccupied TV channels of the TV band are used for data offloading. \\ \hline \end{tabular}
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Table 3: _Cont._cellular coverage, and limits the impact of cellular handovers. Introducing vassalages, i.e., smaller groups of vehicles inseparable from the surrounding traffic, increases efficiency and modularity: vehicles are able to drive at small inter-vehicle distances and allowing the acceleration of platoon management maneuvers. The vassalage size impacts platoon efficiency, the network load as well as the road traffic. The use of smaller vassalages may be suitable in the event of heavy traffic volumes and high ad hoc network loads, since this would facilitate the coexistence with the surrounding traffic as well as shift the load to the cellular network.