Data Aided Symbol Timing Estimation in Space-Time Coded CPM Systems over Rayleigh Fading Channels

Abstract

The technology of space-time coded continuous phase modulation (STC-CPM) has aroused considerable attention recently in wireless communication systems for improving the capacity and data rate without bandwidth expansion. Symbol timing synchronization is an important issue in such systems. In this paper, a data aided symbol timing estimation algorithm was proposed for burst-mode STC-CPM systems over Rayleigh fading channels. A training sequence is embedded before transmission of each packet. The receiver first adds the signals from different receive antennas and then calculates the digital Fourier transformation (DFT) of the phase of the one-symbol differential signal of the sum. The initial symbol timing offset can be estimated from the phase of the tone component of the DFT outputs. MATLAB simulation results show that the variance of the timing estimation error is very small in slow Rayleigh flat fading channels and frequency selective fading channels and the degradation of frame error rate (FER) is significantly small under the condition of non-ideal synchronization. This algorithm is suitable for any numbers of transmit and receive antennas and can estimate the timing offset rapidly and accurately in STC-CPM systems.