公开(公告)号：JPH10206538A

公开(公告)日：1998-08-07

申请号：JP1003198

申请日：1998-01-05

Applicant: LUCENT TECHNOLOGIES INC

Inventor： ALEX PIDWARBEKKY ,  R ANTHONY SHOVER

IPC: G01S13/524 ,  G01S3/48 ,  G01S5/04 ,  G01S13/536 ,  G01S13/74 ,  G01S13/87 ,  G01S13/90 ,  G06K7/00 ,  H04B1/40

Abstract: PROBLEM TO BE SOLVED: To provide FRID(radio frequency discriminator) in which necessary tag data are quickly transmitted even in the case where a plurality of tags exist in a reading area, which has up-link of relatively high speed and in which synchronization is quickly taken. SOLUTION: A radio transmission system generates a first modulation signal modulating a first information signal on a radio carrier signal, and has interrogators 103, 104 for transmitting it. The first information signal instructs by which of a plurality of response modes receiving tags 105-107 responds. At least one tag of the system receives the first modulation signal, and decodes to obtained the first information signal. A backscatterring modulator modulates the reflection of the first modulation signal by means of a second information signal. The contents, the data rate or the modulation of the second information signal are determined by the first information signal to form a second reflection modulation signal. The interrogators 103, 104 receive the second modulation signal, and decode to obtain the second information signal.