Hybrid ARQ with Partial Retransmissions and LDPC codes and its Impact on TCP

The design of a novel HARQ scheme using LDPC codes, partial retransmissions, and diversity combining is presented. The theoretical throughput of the proposed scheme is estimated by means of EXIT charts. It is shown that the proposed method outperforms the classical equal gain combining (EGC) method while requiring few more overall decoding iterations. The transmission control protocol (TCP) performance when the proposed method is used in the physical layer is also investigated. Simulation results show that the gains with respect to the classical EGC scheme can be as large as 3.5 dB.