Joint estimation of carrier frequency and phase offset based on pilot symbols in quasi-constant envelope OFDM satellite systems
Joint estimation of carrier frequency and phase offset based on pilot symbols in quasi-constant envelope OFDM satellite systems
复制标题
DOI：
10.1109/cc.2017.8019135
复制
发表时间：
2017-07
影响因子：
4.1
通讯作者：
Cheng Wang;Gaofeng Cui;Weidong Wang;Yinghai Zhang
中科院分区：
文献类型：
--
作者：
Cheng Wang;Gaofeng Cui;Weidong Wang;Yinghai Zhang
频谱效率和能量效率是卫星系统的两个重要性能指标。准恒定包络正交频分复用(QCE-ofdm)技术可以同时获得较高的频谱效率和较低的峰均功率比(PAPR)。因此，QCE-OFDM技术被认为是一种很有前途的卫星系统候选多载波技术。然而，在卫星系统中，多普勒效应会引起载波频偏(CFO)，而非理想振荡器又会引起载波相位偏移(CPO)。CFO和CPO将进一步导致误码率(BER)性能下降。因此，对CFO和CPO进行估计和补偿是非常重要的。本文分析了QCE-ofdm卫星系统中CFO和CPO的影响。在此基础上，提出了一种基于频域导频符号的CFO和CPO联合估计方法。此外，根据最小Cramer-Rao Bound(CRB)准则，设计了不同导频开销的最佳导频符号结构。仿真结果表明，该方法的估计精度接近CRB。
Spectral efficiency and energy efficiency are two important performance indicators of satellite systems. The Quasi-Constant Envelope Orthogonal Frequency Division Multiplexing (QCE-OFDM) technique can achieve both high spectral efficiency and low peak-to-average power ratio (PAPR). Therefore, the QCE-OFDM technique is considered as a promising candidate multi-carrier technique for satellite systems. However, the Doppler effect will cause the carrier frequency offset (CFO), and the non-ideal oscillator will cause the carrier phase offset (CPO) in satellite systems. The CFO and CPO will further result in the bit-error-rate (BER) performance degradation. Hence, it is important to estimate and compensate the CFO and CPO. This paper analyzes the effects of both CFO and CPO in QCE-OFDM satellite systems. Furthermore, we propose a joint CFO and CPO estimation method based on the pilot symbols in the frequency domain. In addition, the optimal pilot symbol structure with different pilot overheads is designed according to the minimum Cramer- Rao bound (CRB) criterion. Simulation results show that the estimation accuracy of the proposed method is close to the CRB.