Hybrid Automatic Repeat Request (HARQ) in Wireless Communications Systems and Standards: A Contemporary Survey

Abstract

<div>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.</div>

Link-Layer Retransmission-based Error-Control Protocols in FSO Communications: A Survey

“…Among link-layer error-control solutions, retransmission-based methods, including ARQ and HARQ, have more degrees of freedom as compared to ECC schemes, making them a fertile research area in the domain of FSO communications. These protocols have been widely surveyed in the literature of RF communications [47]- [55]. A summary of these works is shown in Table III.…”

“…Makki et al [54] A survey of HARQ using NOMA for RF communications 2021 Ahmed et al [55] A survey of HARQ in RF communications with various emerging wireless technologies This paper A comprehensive survey on the design and performance evaluation of both ARQ and HARQ protocols together with cross-layer design frameworks in various FSO communication scenarios, including point-to-point terrestrial, cooperative, multi-hop relaying, hybrid FSO/RF, satellite/aerial, and deep-space systems in the FSO systems for two remarkable reasons. Firstly, as the bandwidth of FSO systems is much larger than that of RF ones, it is challenging for error-control methods designed for the lower data-rate transmission of RF systems to fully exploit such huge bandwidth.…”