| 摘要 |
<p>A vehicle-to-roadside communication system for communication between a roadside communication station and an on-board mobile station in a cell by OFDM modulation scheme. Even if the Doppler shift increases because the vehicle travels at high speed, interference between carriers does not occur, and the communication quality does not lower. The speed of a vehicle in a cell is measured. The higher the speed of the vehicle is, the more the interval between subcarriers of the OFDM is widen. If the occupied bandwidth of the radio wave assigned according to the Radio Laws is constant, the number of subcarriers in the bandwidth is decreased (thinned). Even if the vehicle travels at high speed, interference between subcarriers does not occur, and the high-quality data communication is possible. Degradation of data transmission rate due to the decrease of the number of subcarriers can be coped with because the number of vehicles in a cell is small.</p> |
