Hybrid Automatic Repeat Request (HARQ) in Wireless Communications
Systems and Standards: A Contemporary Survey
Abstract
Automatic repeat request (ARQ) schemes, and in particular hybrid-ARQ
(HARQ) schemes, which jointly adopt forward error correction (FEC) and
ARQ, are essential to provide reliable data transmission in wireless
communications systems. However, the feedback from the receiver to the
transmitter and the retransmission process used in ARQ incurs
significant cost in terms of power efficiency, throughput, computational
power and delay. Unfortunately, such drawbacks can limit their
applications to several current and emerging technologies. More
specifically, the increasing number of wireless users has create
spectrum scarcity, relying on small-size batteries create power
constraints, deployment of real-time applications boost the demand for
ultralow delay networks, and the ultra-small low-cost internet of things
(IoT) devices has limited signal processing and computation
capabilities. Consequently, extensive research efforts have been
dedicated to overcome the limitations inherent in HARQ. This survey
paper provides an extensive literature review of the state-of-the-art
HARQ techniques and discusses their integration in various wireless
technologies. Moreover, it provides insights on advantages and
disadvantages of particular ARQ types and discusses open problems and
future directions.