With the rapid development of wireless mobile networks, VANET (vehicular ad hoc networks) that adopt transportation tools as mobile platforms have received great attention. Integrating VANETs with wireless infrastructure to provide high-quality transmission services also has become one of the important research topics. Because terminal devices in vehicular environments are highly mobile, a MN (mobile node) will encounter frequent handoffs while accessing wireless network services. However, supposing the chosen handoff AP (access point) presents too long service delay, the quality of the Internet, especially real-time services, like VoIP and multimedia streaming, will be greatly influenced. Therefore, by using the packet scheduling architecture for classified service at APs, this paper proposes a handoff scheme based on service delay prediction. According to the scheduling scheme, we can estimate the load and service delay of different access categories of the regional APs. Our proposed scheme allows the MN requesting real-time services to be allocated to the AP with the lower service delay and the chosen AP thus can reduce the service delay for users.
