Frame synchronisation for frequency redundant transmission of data over power lines

Systems for packet oriented transmission of data over power lines use characteristic patterns-so-called preambles-to mark the beginning of a data frame. Transmission over noisy channels, such as power lines calls for robustness for the detection of these preambles. On one hand this robustness is achieved by the use of spread spectrum techniques, on the other hand by introduction of error-tolerant preamble detection algorithms. Besides the basic selection of a detection strategy, the choice of a suitable preamble sequence and careful choice of thresholds play an important role for the overall performance of the frame synchronisation. This paper evaluates different strategies for preamble detection, examine the dependencies on the mentioned parameters, and make proposals towards an optimum.