Patent ID: 7346127

Claim:
A secure method of deciding on the 0 or 1 state of each bit of a pattern repeated by a static communication channel in a data decompression device, the data decompression device adapted to decompress a block of data including a group of data from a set of data frames compressed by a data compression device, said group including all active channels of the set, where the frames have a structure defined in accordance with a plurality of time slots, each time slot of a first group of time slots is divided into a plurality of information bits carrying a respective communication channel, and an active state, respectively a static state, of each channel is assigned if the comparison of the content of the channel in N bits compared between N frames of a reference pattern with corresponding N bits of N frames of an analysis window, where applicable repeated L times, shows a variation in the content for at least one of the bits, respectively a stability of the content for all of the N bits, where N is an integer greater than or equal to 1, the method comprising: transmitting a descriptor specifying the static or active state of the transmission channel, transmitting the content of the channel that has gone to the static state on the L*N frames of the analysis window after it goes to the static state, performing a statistical analysis, over the analysis window carrying the L*N frames after the channel changes to the static state, of the state of each bit of the pattern repeated by the channel, based on a majority vote of the states obtained for each bit of the channel considered on the L groups of frames in the analysis window, wherein the statistical analysis is intended to reconstitute the original state of each bit of the pattern, wherein a counter is associated with each bit carried by the channel and the statistical analysis includes initializing the counter at the start of the analysis window, a convention for incrementing or decrementing the counter being established in accordance with the successive binary values taken by each bit of the channel within the L groups, the sign of the final value of the counter deciding on the state present in the majority in the L groups.