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About 1,092 papers for “Hybrid automatic repeat request”
Roger G. Kermode · 2012
Reliable multicast protocols scale only as well as their ability to localize traffic. This is true for repair requests, repairs, and the session traffic that enables receivers to suppress extraneous requests and repairs. We propose a new reliable multicast traffic localization technique called Scoped Hybrid Automatic Repeat
Cited by 0
Ade Irawan · JAIST Repository · 2013
Cited by 1
L. Hanzo, Rong Zhang, Lajos Hanzo · 2016
Abstract — A novel Multiplexed Hybrid Automatic Repeat reQuest (M-HARQ) scheme is proposed and compared to the conventional scheme in terms of its energy efficiency, while satisfying specific delay constraints, where the best transmission strategy is discussed for both schemes. By employing the proposed scheme, the transmission rate and power can be reduced, while maintaining the maximum energy efficiency and meeting specific delay constraints. Alternatively, the cell-radius distance may be extended by about 10%, which results in a coverage area extension by a factor of 1.21. I.
Cited by 0
Touraj Soleymani, John S. Baras, Denız Gündüz · 2024
We study feedback control of a dynamical process over a lossy channel equipped with a hybrid automatic repeat request protocol that connects a sensor to an actuator. The dynamical process is modeled by a Gauss-Markov process, and the lossy channel by a packet-erasure channel with ideal feedback. We suppose that data is communicated in the format of packets with negligible quantization error. In such a networked control system, whenever a packet loss occurs, there exists a tradeoff between transmitting new sensory information with a lower success probability and retransmitting previously failed sensory information with a higher success probability. In essence, an inherent tradeoff between freshness and reliability. To address this tradeoff, we consider a linear-quadratic-regulator performance index, which penalizes state deviations and control efforts over a finite horizon, and jointly design optimal policies for an encoder and a decoder, which are collocated with the sensor and the actuator, respectively. Our emphasis here lies specifically on designing switching and control policies, rather than error-correcting codes. We derive the structural properties of the optimal encoding and decoding policies. We show that the former is a threshold switching policy and the latter is a certainty-equivalent control policy. In addition, we specify the iterative equations that the encoder and the decoder need to solve in order to implement the optimal policies.
Cited by 1
Jozef Hamorsky, Udo Wachsmann, Johannes B. Huber et al. · 2007
A novel hybrid automatic repeat request system based on turbo codes, called turbo HARQ system, is proposed. The iterative turbo decoding procedure is exploited to request retransmission of not decodable blocks without the necessity of an outer error--detecting code. It is shown that the turbo HARQ scheme with code rate R c = 1=2 and interleaver length 1024 significantly outperforms the classical turbo coding scheme --- especially for low SNR --- without essential loss in throughput. 1 INTRODUCTION Automatic repeat request (ARQ) protocols are well--known methods to achieve high reliability in digital transmission schemes. The information is protected by an error--detecting block code. If the decoder detects an erroneous transmitted block, retransmission of this block is requested via a feedback channel which is assumed to be error--free throughout this paper. Additionally, the request is assumed to be repeated until the decoder detects error--free transmission. The great advantage of s...
Cited by 0
Wei Wang, Jincheng Dai, Kai Niu et al. · 2020
Cited by 0
Ateeq Ur Rehman, Lie‐Liang Yang, Lajos Hanzo · ePrints Soton (University of Southampton) · 2015
Detecting spectrum holes and efficiently accessing them are the two basic functions that enable a cognitive radio (CR) to make use of the licensed spectrums of a primary radio (PR). In this paper, we consider a CR scheme, which opportunistically accesses a PR channel for communication between a pair of nodes based on the stop-and-wait hybrid automatic repeat request (SW-HARQ). Hence, it is referred to as the cognitive SW-HARQ (CSW-HARQ) arrangement. In our CSW-HARQ system, the PR channel is modelled as a two-state Markov chain having `On' and `Off' states. The CR may only access the PR channel in its `Off' state. In this paper, we analyze both the throughput and delay performance of the CSW-HARQ system, for which a range of closed-form formulas are derived that are also validated by simulation results. Our performance results show that both the activities of PR users and the reliability of the CR channel have a substantial impact on the achievable performance of the CR system.
Cited by 11Open access
2013
Abstract — The introduction of turbo-codes in digital communication systems represents a step towards more reliable data transmissions. The reliability can be enhanced by combining the codes with automatic repeat request (ARQ), known as hybrid-ARQ (HARQ). This paper provides analysis and computer simulations in MATLAB for evaluating the performance of HARQ schemes using turbo-codes as the FEC. The performance of the scheme is analyzed in term of bit error rate (BER) and bit energy to noise ratio spectral density (E b/N 0). Various parameters that influence the performance were investigated. Puncturing effects, number of iterations, decoding algorithm, size of packets and constrain length have been analyzed and evaluated to determine the effects and performances.
Cited by 0
Miaohui Yang · Zenodo (CERN European Organization for Nuclear Research) · 2023
Abstract With the rapid economic development of our country, the number of private cars has increased sharply, which has brought great pressure to the domestic transportation system. At the same time, with the development of communication technology, the amount of data transmitted in 5G communication system has also increased significantly, and users have higher and higher requirements for communication quality. All these have prompted people to put forward new requirements for HARQ re-transmission mechanism, mainly reflected in the pursuit of data transmission rate and system reliability. The traditional HARQ mechanism will bring a lot of redundant re-transmission when the amount of data is large, which will lead to the system performance decline. In order to improve the success rate of information transmission when vehicles pass each other, this paper studies the vehicle-mounted information transmission mechanism. In this case, this paper presents a new hybrid information re-transmission technology, is firstly established by using Matlab simulation software simulation environment to get the data, packet real-time prediction calculation model is established, then based on cloud computing, real-time monitoring of the network environment for predicting to may transmit packets to a transmission or re-transmission consecutive time delay. Taking multiple linear regression and dynamic analytic hierarchy process as the core, the real-time prediction model of data transmission block error rate is constructed, and the framework of decision making and implementation rules of two alternative schemes is set up.
Cited by 0Open access
Yuhua Ouyang, Xiangdong Jia · WIT transactions on information and communication technologies · 2014
Welcome to the WIT Press eLibrary - the home of the Transactions of the Wessex Institute collection, providing on-line access to papers presented at the Institute's prestigious international conferences and from its State-of-the-Art in Science & Engineering publications.
Cited by 0
Rafael Cerna Loli, Onur Dizdar, Bruno Clerckx et al. · arXiv (Cornell University) · 2023
This work investigates the design of Hybrid Automatic Repeat Request (HARQ) strategies for downlink Rate-Splitting Multiple Access (RSMA). The existence of private and common stream as well as their conditioning for Successive Interference Cancellation (SIC), gives rise to an expanded set of opportunities for retransmission of failed packets. Specifically, we devise a scheme in which the retransmissions are scheduled through the common stream, which offers a higher success probability. With this, the common stream needs to carry both new and retransmitted bits, which leads to a layered HARQ (L-HARQ) strategy which is capable of trading off throughput and reliability. Simulation results demonstrate that the devised HARQ scheme outperforms RSMA with conventional HARQ, where each retransmission is handled independently through its own stream. It also helps in closing the throughput gap between HARQ and Adaptive Modulation and Coding (AMC) in the high Signal-to-Noise Ratio (SNR) regime while also achieving a decreased Packet Error Rate (PER) and a lower latency.
Cited by 0Open access
Rafael Cerna Loli, Onur Dizdar, Bruno Clerckx et al. · IEEE Transactions on Wireless Communications · 2024
This work investigates the design of Hybrid Automatic Repeat Request (HARQ) strategies for downlink Rate-Splitting Multiple Access (RSMA). The existence of private and common stream as well as their conditioning for Successive Interference Cancellation (SIC), gives rise to an expanded set of opportunities for retransmission of failed packets. Specifically, we devise a scheme in which the retransmissions are scheduled through the common stream, which offers a higher success probability. With this, the common stream needs to carry both new and retransmitted bits, which leads to a layered HARQ (L-HARQ) strategy which is capable of trading off throughput and reliability. Simulation results demonstrate that the devised HARQ scheme outperforms RSMA with conventional HARQ, where each retransmission is handled independently through its own stream. It also helps in closing the throughput gap between HARQ and Adaptive Modulation and Coding (AMC) in the high Signal-to-Noise Ratio (SNR) regime while also achieving a decreased Packet Error Rate (PER) and a lower latency.
Cited by 10Open access
Gautham Prasad, Vishnu Rajendran, Lutz Lampe et al. · IEEE Open Journal of the Communications Society · 2023
Non-terrestrial networks (NTNs) complement their terrestrial counterparts in enabling ubiquitous connectivity globally by serving unserved and/or underserved areas of the world. Supporting enhanced mobile broadband (eMBB) data over NTNs has been extensively studied in the past. However, focus on massive machine type communication (mMTC) over NTNs is currently growing. Evidence for this are the work items included into the 3rd generation partnership project (3GPP) agenda for commissioning standards for Internet-of-Things (IoT) communications over NTNs. Supporting mMTC in non-terrestrial cellular IoT (C-IoT) networks requires jointly addressing the unique challenges introduced in NTNs and C-IoT communications. In this paper, we tackle one such issue caused due to the extended round-trip time and increased path loss in NTNs resulting in a degraded network throughput. We propose smarter transport blocks scheduling methods that can increase the efficiency of resource utilization. We conduct end-to-end link-level simulations of C-IoT traffic over NTNs. Our numerical results of throughput show the improvement in performance achieved using our proposed solutions against legacy scheduling methods.
Cited by 5Open access
Isobel McFarlane · Enlighten: Theses (The University of Glasgow) · 1991
need Error-Correcting Codes ?1.1.2-Block& Convolution Codes 1.1.3-Errors 1.1.4-Linear Codes 1
Cited by 0Open access
Yun Ai, Marshed Mohamed, Long Kong et al. · Electronics Letters · 2021
Abstract The intelligent reflecting surface (IRS) is an emerging technique to extend wireless coverage. In this letter, the performance of the hybrid automatic repeat request (hybrid ARQ) for an IRS‐assisted system is analysed. More specifically, the outage performance of the IRS‐aided system using hybrid ARQ protocol with chase combining is studied. The asymptotic analysis also shows that the outage performance is better and improves linearly by increasing the number of reflectors of the IRS‐aided system. The results also verify the potential of combining the ARQ scheme in the link layer of the IRS‐aided system and demonstrate that a very small change of path loss condition can impact the performance largely.
Cited by 4Open access
Ruopu Du, Bowen Feng, Yi Yang et al. · 2024
Hybrid automatic repeat request (HARQ) is a potential technique for communication systems in non-terrestrial networks (NTN) to ensure reliability. However, the long round-trip time (RTT) within NTN diminishes the information timeliness when applying HARQ. Moreover, the absence of perfect channel state information (CSI) poses challenges to the precise design of HARQ strategies. In this paper, we introduce a novel coded HARQ scheme for NTN, in which the age of coded information (C-AoI) is proposed as a metric of information timeliness to guide the search for the optimal coded HARQ strategy. The rate-compatible inherited bits codeword construction (RCIC) is introduced for HARQ process to enhance the transmission efficiency. By applying Markov decision process (MDP) and Q-learning algorithm in the optimization, the obtained coded HARQ scheme significantly outperforms the existing schemes in terms of information timeliness and number of transmissions. The throughput of satellite-terrestrial links is also improved.
Cited by 0
Jiangjing Hu, Fengyu Wang, Wenjun Xu et al. · IEEE Transactions on Wireless Communications · 2025
Intelligent task-oriented semantic communications (SemComs) have witnessed great progress with the development of deep learning (DL), where multi-task SemComs that perform multiple tasks simultaneously attach great importance due to its high efficiency. However, the study of robust multi-task-oriented semantics transmission is still in early stages. In this paper, we propose a semantic-aware hybrid automatic repeat request (SemHARQ) framework for the robust and efficient transmissions of multi-task semantic features. First, to improve the robustness and effectiveness of semantic coding, a multi-task semantic encoder is proposed. Meanwhile, a feature importance ranking (FIR) method is investigated to ensure the important features delivery under limited channel resources. Then, to accurately detect the possible transmission errors, a novel feature distortion evaluation (FDE) network is designed to identify the distortion level of each feature, based on which an efficient HARQ method is proposed. Specifically, the corrupted features are retransmitted, where the remaining channel resources are used for incremental transmissions. The system performance is evaluated under different channel conditions in multi-task scenarios in the Internet of Vehicles. Extensive experiments show that the proposed framework outperforms state-of-the-art works by more than 20% in rank-1 accuracy for vehicle re-identification, and 10% in vehicle color classification accuracy in the low signal-to-noise ratio regime.
Cited by 1
Jiangjing Hu, Feng‐Yu Wang, Wenjun Xu et al. · arXiv (Cornell University) · 2024
Intelligent task-oriented semantic communications~(SemComs) have witnessed great progress with the development of deep learning~(DL), where multi-task SemComs that perform multiple tasks simultaneously attach great importance due to its high efficiency. However, the study of robust multi-task-oriented semantics transmission is still in early stages. In this paper, we propose a semantic-aware hybrid automatic repeat request~(SemHARQ) framework for the robust and efficient transmissions of multi-task semantic features. First, to improve the robustness and effectiveness of semantic coding, a multi-task semantic encoder is proposed. Meanwhile, a feature importance ranking~(FIR) method is investigated to ensure the important features delivery under limited channel resources. Then, to accurately detect the possible transmission errors, a novel feature distortion evaluation~(FDE) network is designed to identify the distortion level of each feature, based on which an efficient HARQ method is proposed. Specifically, the corrupted features are retransmitted, where the remaining channel resources are used for incremental transmissions. The system performance is evaluated under different channel conditions in multi-task scenarios in the Internet of Vehicles. Extensive experiments show that the proposed framework outperforms state-of-the-art works by more than $20\%$ in rank-1 accuracy for vehicle re-identification, and $10\%$ in vehicle color classification accuracy in the low signal-to-noise ratio regime.
Cited by 0Open access
Łukasz Łopaciński, Joerg Nolte, Steffen Buechner et al. · 2015
Transmission efficiency is an interesting topic for data link layer developers. The overhead of protocols and coding should be reduced to a minimum. This maximizes a link throughput. This is especially important for high-speed networks, where a small degradation of efficiency will degrade the throughput by several Gbps. We describe a redundancy balancing algorithm for an adaptive hybrid automatic repeat request with Reed-Solomon coding. We introduce a testing environment, most important technical issues, and results generated on a field programmable gate array. The hybrid automatic repeat request and Reed-Solomon algorithms are explained. We provide a mathematical description, and a block diagram of the adaptation algorithm. All necessary algorithm simplifications are explained in details. The algorithm can be represented by basic operations in hardware. In most cases, it finds the optimal coding for a predefined bit error rate.
Cited by 9
Qiang Fu, Jiajia Liu, Jiadai Wang et al. · 2024
Hybrid Automatic Repeat reQuest (HARQ) feedback is one of the key technologies for enhancing the performance of New Radio (NR) Vehicle-to-Everything (V2X) communication. However, for NR V2X messages, HARQ-based retransmission not only improves its delivery performance, but also poses a significant threat to its confidentiality. This paper investigates the Security-Reliability Tradeoff (SRT) of HARQ-assisted NR V2X. To accurately describe the SRT behavior in the V2X scenario, a theoretical framework based on stochastic geometry is developed, carefully considering the random device distributions and physical layer settings of NR V2X. Numerical results prove that this theoretical framework can effectively capture the success probability and secrecy probability of V2X communications under different configurations, including transmission rounds, resource selection, and power control. Furthermore, our analysis shows that the SRT of HARQ-assisted NR V2X can be adjusted by finely tuning the considered configurations.
Cited by 2