IEEE802.11 p is a expanded communication protocol of IEEE 802.11 standard,which can provide an effective MAC(media access control) layer and PHY(physical) layer solution for vehicular communication networks. This paper firstly introduces the physical layer of IEEE802.11 p, then constructs a baseband system simulation model based on IEEE802.11 p PHY using simulink,and analyzes the BER(bit error rate) performance of the system with different modulation, different length of payload and different vehicular environment, which could provide a r...