Importance

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Abstract

A system and method for collecting reference waveforms from authorized wireless telephones in a wireless telephone network. The collected reference waveforms are used by a fingerprint analyzer to distinguish telephone calls made by the authorized wireless telephone from telephone calls made by an unauthorized wireless telephone. The system maintains a pool of specially designated unassigned telephone numbers and selects one telephone number from the pool at random which is provided to a valid subscriber of an authorized wireless telephone. The randomly selected telephone number is to be called by the valid subscriber using the authorized cellular telephone for the purpose of collecting reference waveforms by the system. A radio frequency (RF) receiver of the system monitors and receives transmission signals from a plurality of wireless telephones. Each transmission signal contains a destination telephone number and an identification of its wireless telephone such as MIN/ESN identifiers. The system selects for purposes of collecting reference waveforms the transmission signal whose destination and wireless telephone identification respectively correspond to the randomly selected destination and the identification of the authorized wireless telephone. This ensures that that particular transmission signal belongs to the authorized wireless telephone of the valid subscriber rather than an unauthorized wireless telephone belonging to a pirate since the pirate has no way of knowing the randomly selected telephone number provided to the valid subscriber. The processor then extracts the reference waveform that represents a transmission characteristic of the authorized wireless telephone and stores the extracted reference waveform in memory for use by the fingerprint analyzer.

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First Claim