Error Propagation in Decision Feedback Interference Rejection DS Spread Spectrum Systems

In this paper the performance of a DS spread spectrum communication system operating in the presence of narrowband interference is studied when a decision feedback filter, subject to error propagation, is employed for suppression of the interference. It is shown that when the number of filter taps is less than the system processing gain, the system can be modelled as a Markov chain. Analytical expressions for the transition probabilities are obtained, and the system error rate is shown to be close to that which results from perfect decision feedback.