Radio communications system
US7634088B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Feb 25, 2004 |
| Grant date | Dec 15, 2009 |
| Priority date | — |
| Expiry date | Oct 26, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04W16/24
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.