Extended Synchronizing Codewords for q-ary Complete Prefix Codes

Variable length codes are often used for data transmission. However, a single bit error may cause the loss of some or all subsequent data due to loss of decoder synchronization. It is necessary to devise schemes that resynchronize the decoder to allow the data to again be decoded correctly. Some applications require that the scheme also maintains the position of the decoded symbols in the data stream. Recently, Lam and Kulkarni introduced the concept of an extended synchronizing codeword (ESC) which can be used with an appropriate scheme to prevent propagation errors and also symbol shift errors. We extend their work and show how ESC's can be generated with minimal overhead.