Patent ID: 7664535

Claim:
A control method for high-frequency radio equipment in a base station that receives an extremely low radio wave from a portable equipment comprising the steps of: receiving a signal of an extremely low radio wave which is spread-spectrum modulated according to an initial setting antenna pattern or an antenna pattern formed from an antenna status table; checking an identifier contained in the received data by despread-spectrum demodulation; only when the identifier matches an identifier stored on the receiving side, determining an state of communication environment by determining a code error rate of the received data, comparing the determined code error rate with a threshold value of a code error rate in favorable communication environment set in advance and comparing a difference between the both with a reference value calculated from a past adjustment history; decreasing a spreading ratio and increasing a transmission rate when the communication environment is stable; increasing a spreading ratio and decreasing a transmission rate when the communication environment is unstable; determining whether the error rate has become lower than the former value or not after the increase of the spread ratio; forming an antenna pattern specifying an antenna for reception from a plurality of arranged antennas by referring to the antenna status table when the error rate has not become lower; adjusting synthesized directivity of the plurality of arranged antennas according to the state of the communication environment by selecting an antenna based on the formed antenna pattern; returning the determination processing of the state of communication environment when the error rate has become lower the former value; and repeating from the reception processing of a signal of an extremely low radio wave which is spread-spectrum modulated to the adjustment processing of synthesized directivity of antenna.