基于数据辅助的MPSK信号频域信噪比估计

Data-aided SNR Estimation of MPSK Signals in Frequency-domain

为在载波频率精确恢复前提高多进制数字相位调制(MPSK)信号在低信噪比下的估计精度,提出了一种数据辅助的MPSK信号频域信噪比估计算法。算法在符号定时恢复和帧同步后提取同步段符号,相关运算后在频域进行信噪比估计。仿真结果表明,算法估计均值无偏,不受载波频率误差的影响,在符号长度为512、信噪比为-10 dB时,均方误差与克拉美罗界只有0.15 dB的偏差,特别适合于接收信号包含载波频率误差且要求低信噪比下具有较高信噪比估计性能的应用。

In order to improve the estimation accuracy of Multiple Phase Shift Keying （ MPSK） signals in low signal-to-noise ratio（SNR） condition before the carrier frequency is accurately recovered, a frequency -domain data-aided（ DA） SNR estimator for MPSK signals is proposed. After the symbol timing recovery and frame synchronization,the algorithm is used to extract the pilot symbols, and then estimate the SNR in the frequency domain after correlation processing. Simulation results show that the mean estimation value has no bias and it is not influenced by the carrier frequency error. Under the circumstances that the symbol length is 512 and the SNR is -10 dB,its mean square error （ MSE） and Cramer - Rao lower bounds （CRLB） deviation is only 0. 15 dB, so it is suitable for the applications in which superior SNR performance at low SNR before the carrier frequency recovery is required.