The primary challenge in the current IEEE 802.11p draft standard is the weak performance in multipath environment. Hence a time-domain (TD) and frequency-domain (FD) channel estimation techniques that can enhance the performance of channel estimation are proposed in this paper. The TD technique makes a little modify in current standard to use the symbol prefix to assist channel estimation and obtain remarkable improvement. In addition, the FD pseudo-pilot technique change nothing in the standard and can obtain adequate improvement. Furthermore, this paper also discuss how to employ the preamble to improve the FD channel estimation performance. The channel models adopted for simulation are referencing HIPERLAN/2 and a modified exponential model.