LDPC 코드를 이용한 위상 동기 알고리즘

Abstract

In this paper, we present a carrier phase estimation algorithm for LDPC coded systems. LDPC coded system can not achieve the ideal performance if phase offset is introduced by channel. However, the estimation of phase offset is very hard since the operating point of LDPC is very low SNR. To solve this problem, the algorithm using the tentative soft decision value and based on Maximum Likelihood (ML), was proposed in [2]. But this algorithm has problem which works only under constant phase offset. If phase offset is time variant, it has a severe degradation in performance. To solve this problem, we propose two types of estimators, symbol by symbol estimator: Unidirectional estimator (UDE) and bi-directional estimator (BDE), and sub-block estimator (SBE).