Synchronization for cylic redundancy check based, broadband communications network

Abstract

Abstract A received digital signal is synchronized with a receiver in a communications network by employing a code word which is updated in accordance with a unique update technique. The synchronization arrangement receives the digital signal at a receiver, generates an error check code word over a prescribed portion of the received digital signal and compares the generated error check code word with an expected error check code word in the received digital signal. In response to the comparison result, the generation of the code word and the comparison is iteratged until synchronization is obtained. A new code word is generated as a function of a modified version of the last previously generated code word (previous code word), a function term based on a set of bits dropped from the prescribed portion of the received digital signal, and a set of bits added to the prescribed portion of the received digital signal. In one embodiment, a cyclic redundancy check (CRC) code word is employed. In one instance, the modified version of the code word is obtained by shifting the previous code word to the left dependent on the lead set of bits in the previous code word. In another instance, the modified version of the code word is obtained by shifting the previous code word to the left and then adding the CRC generator polynomial to it, also dependent on the lead set of bits in the previous code word. The function term is representative of a remainder obtained by modifying the dropped set of bits in a predetermined manner and by dividing the modified dropped set of bits by a prescribed CRC generator polynomial. The new CRC code word is then obtained by adding the modified version of the previous code word, the function term and the set of added bits.

Inventors

• 👤 Subrahmanyam Dravida

Bibliographic Details