Conventional Automatic Repeat Request Research Articles

Adaptive Packet Coding for Reliable Underwater Acoustic Communications

This work investigates adaptive random linear packet coding (RLPC) for reliable underwater acoustic (UWA) communications. Our goal is to minimize the total transmission time of data blocks by adjusting the packet coding rate. We first consider the application of RLPC with the conventional automatic repeat request (ARQ) scheme. We dynamically adjust the coding rate to fit the time variations of UWA channels by choosing the optimal number of packets in each transmission. The optimal number of packets in each transmission is obtained based on a dynamic programming (DP) algorithm according to the feedback messages, which contain the number of successfully transmitted packets in the last transmission and the channel state information. Furthermore, considering the long propagation delay of UWA communications, we propose a modified juggling-like ARQ (J-ARQ) for the RLPC scheme, for which the duration of each transmission can be adjusted based on the characteristics of RLPC. A two-step DP algorithm is proposed to find out the optimal solutions for this case. Simulation results show that the proposed schemes can improve the throughput efficiency and reduce the outage probability.

CLARQ: A Dynamic ARQ Solution for Ultra-High Closed-Loop Reliability

Emerging wireless control applications demand for extremely high closed-loop reliability under strict latency constraints, which the conventional Automatic Repeat reQuest (ARQ) solutions with static schedules fail to provide. To overcome this issue and enable data-link layer error control for ultra reliable low-latency communication (URLLC) services, we propose a novel protocol: the Closed-Loop ARQ (CLARQ), which forces to accomplish an information exchange round within a fixed loop-back latency, and dynamically re-allocates the remaining resource between uplink and downlink slots upon the result of last uplink transmission. The proposed method guarantees to meet the latency requirement, while delivering high communication reliability and power efficiency. It can be efficiently offline optimized by means of dynamic programming techniques, and is capable of real-time deployment with a low-cost implementation based on look-up tables. Numerical evaluations have verified that CLARQ outperforms baselines with significantly improved closed-loop reliability and reduced energy consumption. Especially, over a Rayleigh channel with 0dB mean SNR, it is able to provide a closed-loop error rate below 1e-7 within 10ms loop-back latency, which makes our proposal competitive for practical URLLC applications in future 5G-and-beyond networks.

Index Coded Automatic Repeat Request (ARQ)

In this paper, an index-coded Automatic Repeat Request (ARQ) is studied in the perspectives of transmission efficiency and memory overhead. Motivated by reducing significant computational complexity from huge matrix inverse computation of random linear network coding, a near-to-optimal broadcasting scheme, called index-coded Automatic Repeat Request (ARQ) is proposed. The main idea is to consider the principal packet error pattern across all receivers. With the help of coded side information formed by successfully decoded packets associated with the dominant packet error pattern, it is shown that two contradictory performance metrics such as transmission efficiency and transmit (receive) cache memory size for index coding (decoding) can be enhanced with a reasonable trade-off. Specifically, the transmission efficiency of the proposed scheme is proved to be asymptotically optimal, and memory overhead is shown to be asymptotically close to the conventional ARQ scheme. Numerical results also validate the proposed scheme in the sense of memory overhead and transmission efficiency in comparison with the conventional ARQ scheme and the optimal scheme using random linear network coding.

Design and performance evaluation of bitwise retransmission schemes in wireless sensor networks

The previously proposed bitwise retransmission schemes which retransmit only selected bits to accumulate their reliability are designed and evaluated. Unlike conventional automatic repeat request (ARQ) schemes, the bitwise retransmission schemes do not require a checksum for error detection. The bitwise retransmission decisions and combining can be performed either after demodulation of the received symbols or after channel decoding. The design and analysis assume error-free feedback, however, the impact of feedback errors is also considered. The bit-error rate (BER) expressions are derived and verified by computer simulations in order to optimize the parameters of the retransmission schemes. The BER performance of coded and uncoded bitwise retransmissions is compared with a hybrid ARQ (HARQ) scheme over additive white Gaussian noise (AWGN), slow fading, and fast fading channels. It is shown that bitwise retransmissions outperform block repetition coding (BRC) over AWGN channels. In addition, the selection diversity created by the bitwise retransmissions can outperform the HARQ at large signal-to-noise ratio (SNR) over fast fading channels. Finally, the practical design of a bitwise retransmission protocol for data fusion in wireless sensor networks is presented assuming Zigbee, WiFi and Bluetooth system parameters.

Maximization of Underwater Sensor Networks Lifetime via Fountain Codes

The severe nature of underwater channel poses a great challenge for prolonging underwater acoustic sensor networks (UASNs) lifetime and achieving a reliable communication performance. Traditional approaches to improve the reliability such as automatic repeat request (ARQ) negatively affect the network lifetime (NL) due to energy dissipation caused by ARQ retransmission. A forward error correction (FEC) technique called fountain codes (FCs) can solve the energy efficiency problem of ARQ by transmitting both the original packet and some redundant packets to ensure a targeted reliability with few or no retransmissions. In this paper, we investigate performances of both traditional ARQ- and FC-based FEC methods in terms of NL, end-to-end delay, energy consumption, and frame error rate (FER) for UASNs. In this context, we abstract energy dissipation characteristics of conventional ARQ- and FC-based FEC method at the link-layer. We propose an integer linear programming (ILP) framework that maximizes the NL, which is operated on top of developed link-layer energy consumption models. Our results reveal that FC-based FEC methods can prolong the NL at a minimum of 16% while end-to-end delay, energy consumption, and FER can be reduced at least by 11%, 14%, and 9% as compared to classical ARQ, respectively.

Performance Analysis of Cognitive User Cooperation Using Binary Network Coding

We consider a cognitive radio network where a primary and a secondary transmitter, respectively, communicate a message to their primary and secondary receivers over a packet-based wireless link, using a joint automatic-repeat-request (ARQ) error control scheme. The secondary transmitter assists in the retransmission of the primary message, which improves the primary performance, and as a reward it is granted limited access to the transmission resources. Conventional ARQ, as well as two network-coding schemes are investigated for applications in the retransmission phase; namely the static network-coding scheme and the adaptive network-coding scheme. For each scheme we analyze the transmission process by investigating the distribution of the number of transmission attempts. We divide every frame into three transmission sessions and in each session we discover that the number of transmission attempts follows a certain negative binomial distribution, in which case can be further approximated by a normal distribution. Considering both the cases of an adaptive frame size and a truncated frame size, we derive analytical results on system performances and discuss the comparison of three schemes. Besides, the approximation method greatly reduces the complexity of transmission analysis, especially in the truncated frame-size case. Numerical results show that our analysis are valid and closely match the simulations.

Joint Impulsive Noise Estimation and Data Detection Conceived for LDPC-Coded DMT-Based DSL Systems

Impulsive noise is one of the most challenging issues in digital subscriber lines (DSL). In order to mitigate the deleterious effects of impulsive noise, the conventional automatic repeat request invokes cyclic redundancy checking (CRC) in order to estimate the existence of impulsive noise and then triggers retransmission, which degrades the spectral efficiency attained. More straightforward techniques of mitigating impulsive noise, such as blanking and clipping, require specific design, which increases the implementation complexity. Against the background, we propose a novel two-stage joint impulsive noise estimation and data detection scheme conceived for low-density parity-check (LDPC) coded discrete multitone (DMT)-based DSL systems. More explicitly, first of all, we propose a semi-blind estimation method, which is capable of estimating the arrival of impulsive noise without using CRC and additionally evaluating the power of impulsive noise with an adequate accuracy. Second, in order to improve the accuracy of impulsive noise estimation in more advanced LDPC-coded DMT-based DSL systems, we propose a decision-directed method for the second stage of channel decoding and data detection with the aid of extrinsic information transfer (EXIT) charts. Our proposed two-stage scheme is capable of approaching the performance of the idealistic scenario of perfectly knowing both the arrival time and the instantaneous power of impulsive noise. Moreover, we analyze the mean square error of the proposed schemes in order to quantify the estimation accuracy and to reduce the estimation complexity. Our simulation results demonstrate that our proposed scheme is capable of achieving a near-capacity performance to using our LDPC coded DMT-based DSL system in the presence of impulsive noise.

Dynamic Node Cooperation in an Underwater Data Collection Network

In this paper, we consider a practical underwater data collection network, where one destination needs to collect data from multiple underwater nodes. With the conventional automatic-repeat-request (ARQ) protocol, the destination requests retransmission from each node individually without any node cooperation. We propose two protocols, selective relay cooperation and dynamic network coded cooperation, utilizing the fact that underwater nodes can overhear the transmission of the others. In the selective relay cooperation, one node can be selected as a relay to transmit the data from another undecoded node in the retransmission phase. In the network coded cooperation, the selected relay nodes transmit network coded packets to the destination. The relay nodes participating the cooperation are selected by the destination based on the channel quality, as measured by the effective signal-to-noise ratio. In addition to simulation results, we have carried out several lake tests based on a full protocol implementation. Simulation and field testing results demonstrate that the proposed schemes can gain significant performance improvement compared with the conventional ARQ scheme.

An efficient cooperative ARQ protocol for wireless relay networks

An efficient cooperative Automatic Repeat reQuest (ARQ) protocol for distributed space–time coded cooperative networks is proposed in this paper. Conventional cooperative ARQ protocol just utilizes the relays which can decode the packet from the source in direct transmission. However, relays which can not receive the packet successfully have the ability to listen to the retransmission and decode the packet with high probability. Therefore, we consider to let these relays join in the next possible retransmission. We prove that the proposed cooperative ARQ protocol has a lower packet loss rate and average retransmission number than conventional ARQ protocol. Finally, the simulation results verify our theoretical results and show that the proposed ARQ protocol is suitable for the relay networks where the source node is close to the relay nodes.

Proposal of Go-Back-i-symbol ARQ Scheme and its Performance Evaluation in Meteor Burst Communications

In this paper, we propose a new automatic repeat request (ARQ) scheme, named Go-Back-i-symbol (GBi) ARQ scheme, suitable to Meteor Burst Communications (MBC). The scheme realizes symbol-wise ARQ by using the Viterbi decoding algorithm for convolutional codes. We also propose a practical transmission protocol for applying the GBi-ARQ scheme to packet communications over time varying short burst channels such as meteor burst channels. Fundamental performances of the GBi-ARQ scheme in MBC are evaluated by computer simulations. Effectiveness of the GBi-ARQ scheme is shown by comparing the performance with that of a conventional block-wise ARQ scheme.

A Cost Effective Block Framing Scheme for Underwater Communication

In this paper, the Selective Multiple Acknowledgement (SMA) method, based on Multiple Acknowledgement (MA), is proposed to efficiently reduce the amount of data transmission by redesigning the transmission frame structure and taking into consideration underwater transmission characteristics. The method is suited to integrated underwater system models, as the proposed method can handle the same amount of data in a much more compact frame structure without any appreciable loss of reliability. Herein, the performance of the proposed SMA method was analyzed and compared to those of the conventional Automatic Repeat-reQuest (ARQ), Block Acknowledgement (BA), block response, and MA methods. The efficiency of the underwater sensor network, which forms a large cluster and mostly contains uplink data, is expected to be improved by the proposed method.

Performance analysis of single source and single relay cooperative ARQ protocols under time correlated Rayleigh fading channel

In this paper, we analyze the performance of a cooperative Automatic Repeat reQuest (ARQ) protocol under Poisson arrivals and time correlated Rayleigh fading. The conventional non-cooperative ARQ protocol under the same channel environment is also analyzed to compare its performance with that of the cooperative ARQ protocol. A two-dimensional discrete time Markov chain is constructed for the analysis. Using the steady state analysis of the Markov chain, the average frame latency and the probability generating function of the frame service time are derived. We validate our analytical results by comparing them with simulation results. From our analysis, we show that the cooperative ARQ protocol outperforms the non-cooperative ARQ protocol and the effect of the time correlation in the fading channel is not negligible. We also see that the performance metrics which we consider in this paper are almost constant as long as d S R 2 + d R D 2 remains constant, where d S R is the distance between the source node and the relay node and d R D is the distance between the relay node and the destination node.

Design of MAC-defined aggregated ARQ schemes for IEEE 802.11n networks

Based on the IEEE 802.11n standard, frame aggregation is considered one of the major factors to improve system performance of wireless local area networks (WLANs) from the medium access control (MAC) perspective. In order to fulfill the requirements of high throughput performance, feasible design of automatic repeat request (ARQ) mechanisms becomes important for providing reliable data transmission. In this paper, two MAC-defined ARQ schemes are proposed to consider the effect of frame aggregation for the enhancement of network throughput. An aggregated selective repeat ARQ (ASR-ARQ) algorithm is proposed, which incorporates the conventional selective repeat ARQ scheme with the consideration of frame aggregation. On the other hand, the aggregated hybrid ARQ (AH-ARQ) protocol is proposed to further enhance throughput performance by adopting the Reed-Solomon block code as the forward error correction (FEC) scheme. Novel analytical models based on the signal flow graph are established in order to realize the retransmission behaviors of both schemes. Simulations are conducted to validate and compare the proposed ARQ mechanisms with existing schemes based on service time distribution. Numerical results show that the proposed AH-ARQ protocol outperforms the other retransmission schemes owing to its effective utilization of FEC mechanism.

Differentiated cooperative multiple access for multimedia communications over fading wireless networks

The quality of service (QoS) support for multimedia communications faces a big challenge in a fading wireless network. On one hand, conventional automatic repeat request (ARQ) schemes are not effective for small-scale fading channels with correlated errors due to consecutive retransmission failures. On the other hand, large-scale fading due to propagation loss or shadowing severely limits transmission range. A novel differentiated cooperative medium access control (MAC) protocol, called DC-MAC, is proposed to enhance the QoS support for multimedia communications while supporting service differentiation based on the IEEE 802.11e architecture. By enabling cooperative ARQ, the retransmission is initiated from an appropriate transmission queue of an appropriate relay node instead of the original source. Since unnecessary and useless retransmissions may intensify the node contention and degrade the system performance contrarily, a novel negative acknowledgement feedback mechanism is introduced for loss distinguishing and channel estimation such that cooperative retransmission will be employed only when necessary and only by competent nodes. Extensive simulations are conducted on the OPNET platform to analyse the performances of DC-MAC under both small-scale and large-scale fading. Simulation results show that the proposed scheme significantly improves the performances of both multimedia applications and best-effort data applications in terms of throughput, delay and coverage with moderate user contention.

Analytical Framework for Simultaneous MAC Packet Transmission (SMPT) in a Multicode CDMA Wireless System

Stabilizing the throughput over wireless links is one of the key challenges in providing high-quality wireless multimedia services. Wireless links are typically stabilized by a combination of link-layer automatic repeat request (ARQ) mechanisms in conjunction with forward error correction and other physical layer techniques. In this paper, we focus on the ARQ component and study a novel class of ARQ mechanisms, referred to as simultaneous MAC packet transmission (SMPT). In contrast to the conventional ARQ mechanisms that transmit one packet at a time over the wireless air interface, SMPT exploits the parallel code channels provided by multicode code-division multiple access. SMPT stabilizes the wireless link by transmitting multiple packets in parallel in response to packet drops due to wireless link errors. While these parallel packet transmissions stabilize the link layer throughput, they also increase the interference level in a given cell of a cellular network or cluster of an ad hoc network. This increased interference reduces the number of traffic flows that can be simultaneously supported in a cell/cluster. We develop an analytical framework for the class of SMPT mechanisms and analyze the link-layer buffer occupancy and the code usage in a wireless system running some form of SMPT. Our analysis quantifies the tradeoff between increased link-layer quality of service and reduced number of supported flows in SMPT with good accuracy, as verified by simulations. In a typical scenario, SMPT reduces the probability of link-layer buffer overflow by over two orders of magnitude (thus enabling high-quality multimedia services, such as real-time video streaming) while supporting roughly 20% fewer flows than conventional ARQ. Our analytical framework provides a basis for resource management in wireless systems running some form of SMPT and optimizing SMPT mechanisms.

Arithmetic coding-based continuous error detection for efficient ARQ-based image transmission

Block cyclic redundancy check (CRC) codes are typically used to perform error detection in automatic repeat request (ARQ) protocols for data communications. Although efficient, CRCs can detect errors only after an entire block of data has been received and processed. We propose a new continuous error detection scheme using arithmetic coding that provides a novel tradeoff between the amount of added redundancy and the amount of time needed to detect an error once it occurs. This method of error detection, first introduced by Bell, Witten, and Cleary (1990), is achieved through the use of an arithmetic codec, and has the attractive feature that it can be combined physically with arithmetic source coding, which is widely used in state of-the-art image coders. We analytically optimize the tradeoff between added redundancy and error-detection time, achieving significant gains in bit rate throughput over conventional ARQ schemes for binary symmetric channel models for all probabilities of error.

Analysis of memory and incremental redundancy ARQ schemes over a nonstationary channel

A generalized type II automatic-repeat-request (ARQ) scheme using punctured convolutional coding on a two-state Markov model of a nonstationary channel is analyzed. A simple ARQ scheme with memory is also analyzed. It is shown that the simple memory ARQ scheme offers a substantial throughput improvement over a conventional ARQ scheme at severe channel conditions. Furthermore, the generalized type II ARQ scheme yields a better performance than the conventional type II ARQ scheme under all channel conditions, thus making it attractive for use over time-varying channels.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Sequential decoding with an efficient partial retransmission ARQ strategy

The authors present and analyze an efficient partial retransmission automatic repeat request (ARQ) strategy using convolutional coding and sequential decoding in conjunction with code combining. In the proposed ARQ scheme, whenever a packet of data needs to be retransmitted that packet is not repeated entirely as in the case of conventional full retransmission ARQ strategies. Instead, symbols of that packet are repeated a few at a time, sequentially, as needed, hence making a more effective use of the channel. It is shown that partial repetitions and code combining still yields an increase of the apparent Pareto exponent of sequential decoding, as in the case of full repetition-code combining. A throughput analysis shows that the partial retransmission ARQ strategy yields a substantial throughput improvement over the full retransmission-code combining ARQ strategies.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>