基于可变遗忘因子RLS在OFDM系统的载波频偏估计

在时变信道下正交频分复用（OFDM）系统中，通过导频辅助，提出基于可变遗忘因子RLS（VFF-RLS）的载波频偏（CFO）估计改进算法。针对传统RLS（CFF-RLS）算法中遗忘因子无法同时满足CFO估计收敛速度和收敛精度的缺陷，本文设计了线性变化遗忘因子(LFF)和非线性变化遗忘因子(NLFF) 两种可变遗忘因子方案来提升CFO估计性能。仿真结果显示：在低信噪比的情形下，基于VFF-RLS算法的CFO估计性能明显优于基于CFF-RLS算法的CFO估计性能。

Carrier Frequency Offset Estimation for OFDM Systems Based on Variable Forgetting Factor RLS

In orthogonal frequency division multiplexing (OFDM) systems over time-varying multipath channel, the improved pilot-aided carrier frequency offset (CFO) estimation algorithm based on variable forgetting factor RLS(VFF-RLS) has been proposed. Aiming at the defect of constant forgetting factor in traditional RLS(CFF-RLS) algorithm can not simultaneously satisfy convergence speed and convergence accuracy of CFO estimation, In this paper, two variable forgetting factor schemes have been designed for improving CFO estimation performance, namely linear variation forgetting factor(LFF) and non-linear variation forgetting factor(NLFF). The simulation results show that the CFO estimation performance based on VFF-RLS significantly better than the CFO estimation performance based on CFF-RLS algorithm in low SNR conditions.