Nokia Corporation

Amitabh Dixit

Tejas Maheshbhai Bhatt

Victor Stolpman

Nico Van Waes

Jian Zhong Zhang

Apparatuses, computer program products, and methods for authenticating digital signals are provided in which copies of a watermark are extracted from a digital signal with at least some of the copies potentially having distorted values. The original values of the watermark may be reconstructed exclusively based on the extracted copies of the watermark. The method includes estimating one or more bit error rates without training or reference information. The bit error rates are modeled as being equivalent to transmitting the copies through binary symmetric channels. The estimated bit error rates and the distorted values are combined to reconstruct the original values of the watermark. The reconstructed watermark may be compared to an original watermark for authenticating the received digital signal. Also, the estimated bit error rates may be compared to a random sequence of bits for verifying the presence of the watermark without knowing the original values of the watermark.

Apparatuses, computer program products, and methods for authenticating digital signals

A method of adaptive error correction coding includes processing data during a connection between a transmitting entity and a receiving entity, where the data is processed in accordance with a predetermined coding scheme. More particularly, processing data includes encoding one or more sequences received by an error correction encoder of the transmitting entity, or decoding one or more block codes received by an error correction decoder of the receiving entity. During the connection, then, the method includes selecting or receiving a selection of feedback code information. Thus, during at least a portion of the connection, the data processing is switched to processing data in accordance with a parity-check coding technique based upon the feedback code information.

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Dallas, TX, United States of America

Amitabh Dixit