Iterative Recovery for Interfered Scrambling Code Sequence on Factor Graph

Abstract

To solve the problem of insufficient number of check equation in the reconstruction of high order interfered scrambling code sequence, a reconstruction algorithm is proposed. Firstly, the check relationships based on the scrambling code generator polynomial are used to construct the factor graph, and the factor graph iteration method is used to estimate the scrambling code sequences. Secondly, the check relationship inspection method is used to evaluate the compatibility between the iterative estimation sequences and the generator polynomial, and select the best continuous codeword to restore the scrambler initial state. Finally, the optimal reconstruction sequence is selected from the scrambling code for initial state recovery according to the principle of minimum Hamming distance. Simulation results show that the algorithm can effectively solve the problem of reconstruction by using a limited number of check equations.