| 摘要 |
Between communication equipment to be loaded in a vehicle and a base station, CDMA data communication is performed. A speed sensor detects a traveling speed. When the speed sensor crosses a speed determining value, a communication speed is changed. When the vehicle is at a halt or travels at a low speed, the communication speed is set to be high. When the traveling speed exceeds the speed determining value resulting from acceleration, the communication speed is decreased. Satisfactory communication is performed in the whole speed range, and data communication can be performed at the maximum speed. In order to change the communication speed, for example, a chip rate of PN code is changed. Also, the number of PN codes to which parallel processing is simultaneously applied is changed. Thus, it is possible to set the communication speed to be high even in a high-speed mobile object. |
