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 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.展开更多
The Bit Error Rate (BER) caused by Inter Carrier Interference (ICI) increases greatly with the increase of frequency offset in Orthogonal Frequency Division Multiplexing (OFDM) systems. According to a typical OFDM sig...The Bit Error Rate (BER) caused by Inter Carrier Interference (ICI) increases greatly with the increase of frequency offset in Orthogonal Frequency Division Multiplexing (OFDM) systems. According to a typical OFDM signal model, this letter proves that the coefficient matrix of ICI is a unitary matrix whose inverse matrix is much easier to get, and then proposes a new ICI cancellation method with less computation complexity by sending typical pilot symbols. Compared with two existing ICI cancellation methods, self-cancellation and windowing cancellation, it is shown that the proposed algorithm can cancel ICI better and overcome the limitation of the two traditional methods.展开更多
基金supported by the National Natural Science Foundation of China(No.91438114,No.61372111 and No.61601045)
文摘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.
文摘The Bit Error Rate (BER) caused by Inter Carrier Interference (ICI) increases greatly with the increase of frequency offset in Orthogonal Frequency Division Multiplexing (OFDM) systems. According to a typical OFDM signal model, this letter proves that the coefficient matrix of ICI is a unitary matrix whose inverse matrix is much easier to get, and then proposes a new ICI cancellation method with less computation complexity by sending typical pilot symbols. Compared with two existing ICI cancellation methods, self-cancellation and windowing cancellation, it is shown that the proposed algorithm can cancel ICI better and overcome the limitation of the two traditional methods.
