Abstract: The present invention relates to a system and method for reliably transmitting data over wireless communication channels. The invented system 10 comprises a transmitting device 12 having an error control coding circuit 20 and an interleaver circuit 22 in communication with each other. The invented system 10 also includes a receiving device 14 having an error control decoding circuit 26 and a de-interleaver circuit 28 in communication with each other. The transmitting device 12 and the receiving device 14 communicate over a wireless communication channel 16. The error control coding circuit 20 applies an error control code to the data before it is transmitted over the communication channel 16. The data is also interleaved prior to being transmitted. After transmission over the communication channel 16, the data is de-interleaved and any transmission errors are detected and corrected.

Abstract: The invention is a system for digital watermarking that operates on a conventional digital video stream to etch, on hand, and read, on the other hand, digital watermarks in the stream that do not visibly interfere with the video content. A system according to the invention operates on digital data that has been transformed into the spatial-frequency domain, using inter-block differences between spatial-frequency coefficients to encode the bits of a digital watermark. Using the principles of the invention, it is possible to encode multiple watermark bits between two adjacent blocks, thus providing higher watermark data rates relative to underlying video content.

Abstract: A method of generating a authentication code (“MAC”) with improved error tolerance exhibits improved survivability against acceptable signal distortions such as recompression. A method of generating a message authentication code associated with an image includes receiving blocks of image coefficient data where each coefficient has an original value falling within a range of values. The range of values is divided into first and second regions both having allowed coefficient values, and an error tolerance buffer region formed between the first and second regions having disallowed coefficient values. The original values of DC coefficients from each block of the image coefficient data is mapped to a modified value contained in one of the first and second regions, but not contained in the error tolerance buffer region. A MAC is generated as a function of the most significant bits of the modified image coefficient values.

Abstract: According to the principles of the invention, there is provided a system for generating a message authentication code for a conventional digital video stream. The system operates on the rows and columns of block data for a video stream, and more specifically on histograms of DC coefficients from each row and column, to produce a compact code that is nonetheless descriptive of the underlying images in the video stream. The message authentication code can be reproduced from the images of a received video stream, and if desired, compared with a digital watermark embedded in the video stream in order to confirm the accuracy of the video content or identify the source of the video stream.

Abstract: The present invention relates to a system and method for reliably transmitting Internet Protocol (IP) data packets over fading Internet communication channels. The invented system 10 comprises a transmitting device 12 having an interleaver circuit 22. The invented system 10 also includes a receiving device 14 having a de-interleaver circuit 38. The transmitting device 12 and the receiving device 14 communicate over a fading Internet communication channel 16. The transmitting device 12 applies error control coding to the IP packets before they are transmitted over the fading Internet communication channel 16. The Interleaver circuit 22 interleaves the IP data packets before transmitting them over the fading Internet channel 16. The receiving device 14 receives the interleaved IP packets from the fading Internet channel 16. The de-interleaver circuit 38 de-interleaves the received IP data packets.