Design and performance evaluation of feedforward timing estimator for M-PSK signals

In this paper, we propose two new non-data-aided (NDA) feedforward timing estimators requiring 4 samples per symbol, absolute value of in-phase and quadrature (AV-IQ) and log absolute value (LOG-AV). They adopt similar system structure to conventional estimators. The mean estimated value (MEV) and mean square error (MSE) of normalized timing jitter of the proposed timing estimators are analyzed by simulation. Results show that, for binary phase shift keying (BPSK) signals, both proposed estimators are insensitive to residual phase offset and AV-IQ performs much better than other estimators. For high order modulation, AV-IQ can also achieve good jitter performance under perfect carrier phase recovery. But at high SNR, the MEVs of estimators with log function term are not accurate enough with perfect SNR estimation. Comparing with conventional estimators, the proposed estimator AV-IQ has lower complexity while LOG-AV is also acceptable.