LOCATION DETECTION SYSTEM, TRANSMISSION DEVICE, SERVER, AND RADIO SIGNAL COLLISION AVOIDANCE METHOD IN THE SYSTEM

摘要

PPROBLEM TO BE SOLVED: To reduce an electric power consumption of tags while avoiding collisions of radio signals. PSOLUTION: By shifting a transmission time by inserting a stand-by time inherent to a tag (TG) between the reception of a first radio signal and the transmission of a second radio signal, or by transmitting the second radio signal to a server with information on the measurement on the field strength of the first radio signal by the tag and the short setting of the stand-by time when the field strength is small, the server (SV) computes the stand-by time on the basis of a code indicated by the second radio signal received from the tag. Collisions may be avoided by the insertion of a signal in the first radio signal, the reading of its information by the tag, and determination as to whether to transit the second radio signal or not according to rules. PCOPYRIGHT: (C)2006,JPO&NCIPI