Enhanced pilot symbol aided decision directed channel estimation with hybrid ARQ

An improved pilot symbol aided decision directed channel estimation structure is presented, in which data symbol decisions are made from SISO demodulation instead of from a RAKE receiver. Taking advantage of a priori information from previous transmissions, more accurate channel estimation can be achieved in hybrid ARQ chase combing (CC) and partial incremental redundancy (PIR). Simulation results show that the improved structure outperforms the traditional one substantially.