Analysis of the interaction between linear cyclic error correcting codes and self-synchronous payload scramblers

In order to protect public network data transmission from potential Layer 1 attacks by malicious users, self-synchronous scramblers have come into widespread use. Such networks include those using ATM, packet over SONET (POS), and the new generic framing procedure (GFP). Unfortunately, feedback taps inherent in self-synchronous descramblers cause multiplication of transmission errors, which in turn degrades the performance of most linear cyclic error detection/correction codes. This paper analyzes this scrambler/code interaction with respect to the resulting probability of undetectable errors and transmission error correction capability. The theoretical criteria are derived for a linear cyclic code to maintain its error detection and correction performance in the presence of the scramblers. A novel approach for improving the error correction capabilities is also presented.