Hybrid-ARQ Transceiver for OFDM System

Abstract

In this work, we present a novel method which employs joint Automatic Repeat reQuest (ARQ) mechanism for Partial Automatic RepeatreQuest(PARQ)inmultiple-inputmultiple-output(MIMO) systems with orthogonal frequency division multiplexing (OFDM) signaling. The thought behind PARQ is to retransmit only partial copy of information symbols sequence rather than retransmitting the whole sequence. The receiver makes use of joint detection by exploiting observations from multiple transmissions. As a direct consequence of partial retransmission, the bandwidth and power efficiency of the overall system is improved considerably without much decrease in the performance. The channel estimation is pivotal to any communication system and its estimation error directly affects the performance of MIMO-OFDM system. In order to acquire channel knowledge, conventional communication systems rely on pilot assisted approaches at the expense of bandwidth and power resources. In this work, we omit training sequenceduringretransmissionandcombinebothblindandtraining based strategies to estimate channels in semi-blind fashion. In ordertoevaluateefficacyoftheproposedPARQmethod,wealsoprovide throughput comparison between Chase-Combining hybridARQ (CC-HARQ) approach with proposed partial ARQ method.