Abstract:
This short-distance radio communication system for a vehicle includes an in-vehicle unit having more than one antenna and a portable unit performing radio communications with the in-vehicle unit. The in-vehicle unit transmits a first burst together with a call signal for calling the portable unit through a first antenna, and transmits a second burst subsequent to the first burst through a second antenna. The portable unit receives the signals transmitted from the in-vehicle unit, measures respective received signal strength indicators from the first burst and the second burst contained in the received signals, and responds to the in-vehicle unit according to results of comparing the respective indicators with given thresholds.
Abstract:
This vehicular near field communication system has a configuration where a portable device receives a first signal and a second signal respectively transmitted from a vehicle-exterior antenna and a vehicle-interior antenna of an on-board instrument mounted in a vehicle, measures a first received signal strength from the first signal, measures a second received signal strength from the second signal, adds an offset to the second received signal strength, and transmits a response signal to the on-board instrument in accordance with the first received signal strength and the second received signal strength added with the offset, so as to be able to prevent a portable device from being locked in a cabin even though the portable device is shielded by a metal in the cabin.