The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 15, 2009
Filed:
Feb. 25, 2004
Hideichi Sasaoka, Kyotanabe, JP;
Tomoyuki Aono, Kyoto, JP;
Takashi Ohira, Kyoto, JP;
The Doshisha, Kyoto, JP;
Advanced Telecommunications Research Institute International, Kyoto, JP;
Abstract
A radio communications system includes radio devices, and antenna and an array antenna. The radio devices communicate a prescribed signal via the antenna and the array antenna in a system of transmission and reception at a single frequency, such as time division duplex, as the array antenna changes the in directivity to form a plurality of directivities. The radio devices detect a plurality of received radio waves' strength to produce receive signal profiles, respectively, indicating a plurality of strength profiles. The radio devices multivalue strength of the receive signal profiles, respectively, and generate private keys having the multivalued plurality of values serving as a bit pattern.