Current vehicular communication systems are disadvantageous in dealing with a full-range futuristic intelligent transportation system (ITS) with regard to coverage and cost. On the contrary, TV white-spaces have the potential to provide a wide-coverage, large-capacity, and cost-effective connectivity for ITS because of the excellent propagation properties, and there are increasing demands for applying IEEE 802.22 to mobile communication system capable of a wide coverage of 10-30 km. Meanwhile, since IEEE 802.22 was standardized as a fixed communication system, its scattered pilot pattern hinders accurate channel estimation in a highly mobile environment due to the Doppler shift and long-delay multipath fading. In this paper, we propose a reliable channel estimation scheme enabling an IEEE 802.22-based mobile communication system in rural areas without altering physical layer parameters. The proposed scheme effectively uses pilot symbols in adjacent subcarriers to extend interpolation range and shorten interpolation interval and offers high-accurate and stable channel estimation while maintaining flexibility in downstream/upstream ratio. As a simulation result, our proposed scheme sufficiently achieves a required bit error rate of 2 × 10^-4 in a highly mobile long-delay multipath fading environment even in the presence of high carrier frequency offset.