RSU-coordinated Multi-channel MAC with Multi-criteria Channel Allocation

In Vehicular Ad hoc NETworks (VANETs), IEEE 802.11p MAC (WAVE MAC) and its variations suffer from low spectrum efficiency, especially in densely populated Vehicular-to-Infrastructure (V2I) communication scenarios. Focusing on multi-channel coordination and allocation, this paper proposes a Road Side Unit (RSU)-coordinated multi-channel MAC with a centralized multi-criteria service channel allocation and scheduling scheme. By separating safety function from control function and further dividing safety messages into different types, the temporal-spatial division works better under the coordination of RSU. The main contribution of this work is introducing Analytic Hierarchy Process (AHP) model to solve the transmission opportunity allocation problem under multiple criteria, maintaining a relatively high throughput even in densely populated scenarios, while QoS of high priority application is guaranteed. Simulation has been conducted to validate the proposed allocation scheme, and results show that it outperforms WAVE, especially in densely populated scenarios.