Joint Synchronization and Channel Estimation Algorithm of FH-OFDM Systems in Aviation Mobile Communications

A joint synchronization and channel estimation algorithm based on Recursive Least Squares (RLS) is proposed for frequency hopping orthogonal frequency division multiplexing (FH-OFDM) systems in aviation mobile communications above sea. Complex computation is avoided by mitigating Inter-Carrier Interference (ICI) in time domain, which is induced by Carrier Frequency Offset (CFO) and Sampling Frequency Offset (SFO). Linear RLS estimation error function is proposed to estimate CFO, SFO, and Channel´s Impulse Response (CIR). Improved ML estimate scheme for the initial value of CFO and SFO is presented, enhancing the performance and convergence of RLS algorithm. Relation of bandwidth efficiency and hop rate in FH-OFDM system is expressed to balance system parameter. Simulation results under calm sea and rough sea show that the algorithm we proposed outperforms conventional algorithms with the hop rate of 1000 hop/s.