Recently, vehicular communication has become an important application in wireless communications. The Long Term Evolution (LTE) system is considered as one candidate to realize vehicular communication due to many reasons, such as: 1. The LTE system provides extensive coverage. 2. The LTE system provides low transmission latency. 3. In Release 12, the LTE system supports ProSe device-todevice (D2D) service, which can be extended to support vehicular communication.