A low complexity carrier recovery and frequency estimation algorithm for Iridium handset system
S.-M. Hwang, Mao Yu, Lin Yang · 2003
This paper presents a low complexity carrier recovery and frequency estimation algorithm tailored for Iridium satellite communication handset system. The algorithm can acquire carrier frequency from large Doppler offset (larger than symbol rate) in short preamble period and track carrier frequency and phase for the rest of the TDMA slot. It also accurately estimates Doppler offset at the end of the slot. This final Doppler estimation value is further used in upper layer and satellite for Doppler prediction and pre correction. Simulation results show that with at /spl plusmn/37.5 KHz Doppler frequency offset at 4.5 db E/sub b//N/sub a/, the estimated Doppler frequency error and standard deviation is less than 1 Hz, and 3 Hz, respectively.