Performance Analysis of Multiple Packets Combining Decoding in HARQ

From the essence, HARQ is a joint multiple packets decoding technique. Two existing schemes, diversity combining and code combining, only make use of channel output symbols before decoding. Considering the correcting ability of FEC, output code combination is proposed. The output of decoder can be viewed as another output packet of transmission packet passing through a better channel. So it can be combined with new received channel erroneous packet. By means of analytical derivations and simulation, new combining scheme outperforms existing schemes. It greatly reduces system transmission delay without remarkable complexity increases