Time coordinated V2I communications and handover for WAVE networks

A wide variety of information technology (IT) services will become available for vehicles through the IEEE 802.11p, IEEE 1609, and wireless access in vehicular environment (WAVE) standards, and naturally the need for service handover will become a necessity. For WAVE networks, a time coordinated medium access control (MAC) protocol named WAVE point coordination function (WPCF) is proposed in this paper. The mathematical derivations and simulation analysis demonstrate that the proposed WPCF protocol can significantly enhance the utilization efficiency and can support more users based on an equal-length access period when compared to point coordination function (PCF), enhanced distributed channel access (EDCA), or hybrid coordination function (HCF) controlled channel access (HCCA) for vehicle to infrastructure (V2I) communications. The paper also demonstrates the effectiveness of the proposed WAVE handover controller (WHC) and WPCF in minimizing service disconnection time when used for V2I handover. In addition, technical enhancements and messages are added to enable seamless communication services over soft-handover (SHO), and enable minimum handover delay in hard-handover (HHO) situations. The mathematical performance evaluation and the simulation results show that the proposed scheme can significantly improve the handover latency compared to the performance that can be delivered by the current protocols.