IEEE 802.11p has been proposed to extend the application of IEEE 802.11 to Wireless Access fast fading Vehicular Environments (WAVE).Due to the high velocities of vehicles and thus the inconstant topology of networks,it is extremely difficult to maintain communications without handoff in an Intet of Vehicles (IoV).Hence,fast handoff from one roadside unit (RSU) to another is necessary.Although some solutions have been given in IEEE 802.11 r and 802.11 f standards,the handoff latency is still as high as about 50 ms when adopting them.To address this issue in WAVE systems,a novel position-based handoff (PHO) scheme is proposed in this paper.In PHO scheme,the triggering of the handoff is accomplished by the location information of a vehicle instead of the power level of the received signal.Both the handoff process and latency of PHO scheme are analyzed Finally,to verify the analytical results,simulations were con ducted to date the effectiveness of the proposed PHO scheme.