Maximum Likelihood Sequence Detection of a Bit-stuffed Data Source

Bit-stuffing is used in various communications protocols, typically as a way to remove ambiguity in the detection of control flags or as a method to aid clock recovery. Typically a demodulator makes hard symbol-by-symbol decisions without incorporating the knowledge that the data source is bit-stuffed. A demodulator making symbol-by-symbol decisions is clearly not optimum for a source that has been bit-stuffed. In this paper we investigate an optimum approach. We develop the maximum-likelihood sequence detector (MLSD) for a bit-stuffed data source. We start by modeling the transmitted signal as a Markov process. We then proceed to calculate approximate performance bounds for the MLSD. We then develop a trellis receiver structure and perform simulations using the Viterbi decoder algorithm.