On Synchronization of Convolutional Codes

Loss of Synchronization may have a number of effects on the decoding process of a convolutional code. At best there will be a transient effect on the decoder; at worst error propagation will be initiated; or the information sent Will be made worthless by a loss or gain of digits during transmission. A method for detecting and correcting slippage similar to that used for cyclic codes will be examined and applied to certain Specific convolutional codes. This method is such that there is no change in the code when synchronization is maintained. Only a modest amount of added hardware is needed. The procedures developed are applicable to codes where
n
-data streams are sent in parallel. For interlaced serial streams, slippage correction of
s
digits can be corrected if
s
is a multiple of
n
; otherwise slippage can be detected.