초록 ▼

A transmitter identification system to determine if cellular phones in a cellular phone system are authorized as distinguished from cloned phones, operated by fraudulent users, that are unauthorized. Components used in the manufacture of cellular phones vary slightly from one phone to anther so that

A transmitter identification system to determine if cellular phones in a cellular phone system are authorized as distinguished from cloned phones, operated by fraudulent users, that are unauthorized. Components used in the manufacture of cellular phones vary slightly from one phone to anther so that, when the phones are used, the transmitter signals from each phone have different external signal traits. For each cellular phone call, the transmitter signal is received and characterized using a received set of features resulting from the external signal traits. The received set of features is compared with previously stored sets of Features in a database to determine if the call is authorized or unauthorized and, if unauthorized, the call is stopped and access to the fraudulent user is denied.

대표청구항 ▼

[ What is claimed is:] [1.] A transmitter identification system comprising:a plurality of transmitters each for generating a transmitter signal including internal data traits and external signal traits;receiving means located remote from said transmitters for receiving, for each of said transmitters

[ What is claimed is:] [1.] A transmitter identification system comprising:a plurality of transmitters each for generating a transmitter signal including internal data traits and external signal traits;receiving means located remote from said transmitters for receiving, for each of said transmitters, said transmitter signal;characterizing means connected to said receiving means for characterizing one of said transmitters and for generating a plurality of characterizing signals for said one transmitter, wherein the characterizing means generates said plurality of characterizing signals by measuring features of said external traits of said one of said transmitters from at least one of a first category including variations of specified parameters of said one of said transmitters, and a second category including variations in non-specified parameters; andconverting means connected to said characterizing means for converting said plurality of charaterizing signals into a security pattern wherein said security pattern is used to identify said one of said transmitters.