Automatic Repeat Request Mechanism Research Articles

Performance Modeling and Analysis of BASUR-CARQ Protocol Based on Interrelay Interference Cancellation

To recover the performance loss of nodes in half-duplex mode, this paper proposes a buffer-aided successive relay protocol based on cooperative automatic repeat request mechanism (BASUR-CARQ). Based on the fact that interrelay interference (IRI) will occur when relay nodes transmit or receive simultaneously, an interference cancellation operator is proposed to determine whether the interference is eliminated to reduce the outage probability. Moreover, a delay model for data frame transmission is proposed based on CARQ mechanism, and a closed-form expression for the average delay is derived. A 6-state discrete-time Markov chain (DTMC) model is developed to obtain the system throughput, and a closed-form expression for the system energy efficiency under M-ary modulation is derived. Finally, the simulation results show that with the setting of parameters that can balance the main performance, the delay performance of BASUR-CARQ protocol is significantly enhanced compared to the traditional protocols, and the throughput of BASUR-CARQ protocol is also optimized at high signal-to-noise ratio (SNR). Meanwhile, the energy efficiency of BASUR-CARQ protocol is significantly improved for the successive relay communication system without interference cancellation technique.

Multi-sector discrete-time channel model for data link layer evaluation of CubeSat communications

Innovation in the space sector is going through a fruitful period. Among other factors, this has been a consequence of the CubeSat paradigm and its acceptance in the educational, scientific, and commercial sectors, as well as its relevant role in the integration of terrestrial and satellite communication systems. Nevertheless, there is no standardized communication protocol for CubeSat technology. One of the reasons for this lack of standardization is the nonexistence of a widely accepted communication channel model for fast development and simulation of CubeSat technology at the data link layer level. Aiming at filling this gap, we propose a communication channel model that captures both the dynamics of the CubeSat in the low earth orbit and the propagation environment where the terrestrial devices are located, taking into account the elevation angle. For this purpose, finite state Markov chains are used to model the time evolution of the channel fading through the satellite trajectory when it passes by the ground point target. Then, CCSDS recommendations are used as a study case for the data link layer of a CubeSat, while an adaptive automatic repeat request mechanism, according to the elevation angle, is simulated and optimized, showing the usefulness of the proposed channel model.

Reinforcement learning-based link adaptation in long delayed underwater acoustic channel

In this paper, we apply reinforcement learning, a significant area of machine learning, to formulate an optimal self-learning strategy to interact in an unknown and dynamically variable underwater channel. The dynamic and volatile nature of the underwater channel environment makes it impossible to employ pre-knowledge. In order to select the optimal parameters to transfer data packets, by using reinforcement learning, this problem could be resolved, and better throughput could be achieved without any environmental pre-information. The slow sound velocity in an underwater scenario, means that the delay of transmitting packet acknowledgement back to sender from the receiver is material, deteriorating the convergence speed of the reinforcement learning algorithm. As reinforcement learning requires a timely acknowledgement feedback from the receiver, in this paper, we combine a juggling-like ARQ (Automatic Repeat Request) mechanism with reinforcement learning to minimize the long-delayed reward feedback problem. The simulation is accomplished by OPNET.

Average Throughput Analysis and Optimization in Cooperative IoT Networks With Short Packet Communication

Internet of Things (IoT) is a promising paradigm to provide massive wireless connections in the future communications. One main feature of IoT is short packet communication (SPC), which adopts finite block-length codewords for data transmissions. Different from the long packet transmission (i.e., infinite block-length codewords) in conventional wireless networks, SPC suffers from a significant packet error rate even when the transmission rate is smaller than the Shannon capacity. To enhance the transmission efficiency as well as the reception reliability, we introduce cooperative relaying to the IoT network and propose a cooperative IoT protocol. Then, we analyze the average throughput of the cooperative IoT protocol with an approximated closed-form expression. Based on the closed-form expression, we design both optimal and suboptimal transmission rates to maximize the average throughput. Numerical and simulation results have validated the correctness of the theoretical analysis, and show that the maximum average throughput with the optimal/suboptimal design almost overlaps with the simulation results. Besides, we compare the proposed protocol with the automatic repeat request (ARQ) mechanism in terms of both the optimal transmission rate and the maximum average throughput, and observe that the proposed protocol outperforms the ARQ mechanism, especially for a medium/large number of cooperative users.

A Novel Error Correction Mechanism for Energy-Efficient Cyber-Physical Systems in Smart Building

Smart building is an effective solution to address the issue of energy consumption in today’s cyber-physical systems (CPSs) connected world. As an important tool to collect information from a fleet of electric appliance that installed in the building scope, a wireless sensor network is widely employed for this purpose. In this paper, we propose to incorporate forward error correction into the media access control layer of IEEE 802.15.4 standard for packets transmission, as the originally used automatic repeat request mechanism is a timing and energy consumed process that should be avoided in a noisy wireless channel of a smart building environment. Based on the developed CPS simulation platform, the bits error rate and packets error rate of convolutional codes (CCs), Reed-Solomon (RS) codes, and their concatenated codes are intensively investigated, on condition of been applied to different packet length and code rates. We show that the CCs are superior to other codes in most cases. However, the RS and CCs concatenated codes are good candidates, and the RS codes with larger symbol length are preferred for a longer packet. In this regard, future research will concentrated on non-line-of-sight wireless channel, and take the pulse interference from other devices into account.

ASRQ: Automatic Segment Repeat Request for IEEE 802.15.4-Based WBAN

In a wireless body area network (WBAN), high data reliability and long operating time are important requirements. The retransmission process of the default Automatic Repeat reQuest (ARQ) mechanism in IEEE 802.15.4 is a suitable method to ensure the data reliability of WBAN communications, where frame loss can occur frequently. However, retransmitting the entire DATA frame is energy inefficient due to the fact that the most of payload data within lost frames are only partially corrupted. Therefore, this paper proposes the automatic segment repeat request scheme for the IEEE 802.15.4-based WBANs. The proposed scheme partitions the data payload into segments when the channel condition is bad, and retransmits only the corrupted segment(s). This reduces the size of the retransmitted frames, which improves frame reception rate and decreases the amount of transmitted traffic, and thus energy consumption. Our experiments using a real IEEE 802.15.4-based WBAN test bed show that the proposed method provides higher transmission reliability and lower power consumption than the default IEEE 802.15.4 ARQ mechanism.

QoS-aware Opportunistic Cooperative ARQ Mechanism of Sensors Based on Channel state Sensing for Internet of Things

It is well known that the performance of Internet of Things application services is easy to be affected by internal noise of sensor, external environment interference and constriction of system resource. In order to solve the above problems, we studied the characteristics of bit error rate, outage ratio, signal to noise, and scale of relay sensors with channel state to choose the optimal transmission control scheme between direct mode and cooperative mode, building upon which we proposed the opportunistic cooperative automatic repeat request (ARQ) mechanism based on the rules and features of throughput ratio, average delay, packet error rate and energy efficiency, in consideration of retransmission time and channel quality. More importantly, the proposed opportunistic cooperative ARQ mechanism could set up the max retransmission time and control the progress of cooperative transmission according to the real-time network and sensor state, as well as Quality of Services (QoS) guarantee requirements of Internet of Things applications. The mathematical analyses and experiment results show that the proposed scheme is superior to the QoS provisioning schemes based on cooperative ARQ alone and direct transmission with channel state alone in terms of reliability, real time performance and life cycle of system, as well as energy efficiency.

Partial automatic repeat request transceiver for bandwidth and power efficient multiple‐input–multiple‐output orthogonal frequency division multiplexing systems

In this study, the authors present a novel method to improve the performance of automatic repeat request (ARQ) protocol for multiple-input–multiple-output systems that use orthogonal frequency division multiplexing signalling by incorporating partial ARQ (PARQ) mechanism. As a typical ARQ frame has few number of errors, it is useful to retransmit partial sequence of symbols and recover from errors by consuming relatively low bandwidth. The observations from the first transmission and subsequent retransmission are used for joint detection. As a direct consequence of partial retransmission, the bandwidth and power efficiency of the overall system is improved considerably without substantial decrease in the performance. They achieve further bandwidth saving by omitting pilot sequence from the partial retransmission and acquire channel estimate in semi-blind fashion. Partial retransmission of the original information symbol sequence allows the authors to formulate second-order statistics based joint blind channel estimation problem by combining observations from two transmissions. Channel estimation ambiguity inherent to blind methods is resolved by combining cost functions of blind detection and least-square estimator. To evaluate efficacy of the proposed PARQ method, they compare throughput of chase-type hybrid-ARQ and the proposed PARQ methods.

The combined automatic repeat request and rate control mechanism in S‐band mobile interactive multimedia asynchronous return link—design background, parameter dimensioning and first experimental results

SUMMARYIn the S‐band mobile interactive multimedia specification, an asynchronous access using Enhanced Spread Spectrum Aloha random access has been defined for occasional messaging applications. This access scheme is complemented by a combined automatic repeat request and terminal rate control mechanism that is described in this paper. Furthermore, a queuing theory‐based model is developed to describe the behaviour of the automatic repeat request mechanism, and performance results from the first proof‐of‐concept implementation are presented. Copyright © 2014 John Wiley & Sons, Ltd.

Low‐density parity‐check and fountain code performance over mobile wireless optical channels

ABSTRACTBy considering error control in different layers, the efficiency of several mechanisms is discussed in the context of wireless optical transmission of mobile health care application data. In this respect, we assume an emitter placed on a monitored patient and a fixed receiver. Because of patient mobility and health care data rate, the wireless optical channel is fading slowly. To ensure reliable communication, we study in the physical layer the low‐density parity‐check code performance by analysing the results in terms of outage probability. Concerning the application layer, we explore fountain codes, which are also known as Luby transform codes, together with an automatic repeat request mechanism by determining the related outage capacity. Taking into account the performance of both layers, we show that it is possible to design the physical layer code rate in that we maximise the effective data rate in the application layer. Moreover, we point out that Luby transform and low‐density parity‐check codes constitute an efficient and robust mechanism to reduce optical emitted power, which is of main concern for health care application. Copyright © 2014 John Wiley & Sons, Ltd.

A comparative study of packet combining based error recovery schemes for wireless networks

To provide reliable communications in wireless environments, two fundamental error control mechanisms, automatic repeat request (ARQ) and forward error correction (FEC) are proposed. However, the ARQ mechanism may suffer frequent retransmissions and the FEC mechanism incurs bandwidth overhead. To reduce the number of retransmissions and support efficient correction, previous studies have proposed numerous packet combining based error recovery schemes. This study investigates the recovery performance of three packet combining based error recovery schemes, including the extended ARQ (EARQ), the merge strategy in the simple packet combining (SPaC–M), and the destination packet (DPC) schemes through the mathematical analysis and simulations. Results present that the EARQ outperforms the SPaC–M and the DPC in recovery speed in case of a large packet length and a high bit error rate. However, the EARQ is not suggested if the space overhead is the major consideration.

Cooperative overlay secondary transmissions exploiting primary retransmissions

We introduce an overlay cooperative cognitive radio scheme, in which the secondary network transmits only during the retransmissions of the primary network. The secondary network makes use of multiple relays in order to increase its performance compared to a non-cooperative scenario. Moreover, the secondary operates without harming the performance of the primary network. Different cooperative protocols are employed and associated with hybrid automatic repeat request mechanisms. Our results show that the incremental decode-and-forward technique allows the secondary network to achieve the highest throughput among the considered methods, at the cost of a very small degradation in the performance of the primary network.

ARQ-based spectrum sharing with multiple-access secondary system

We consider a cognitive radio network in which a multiple-access secondary system coexists with an automatic repeat request (ARQ)-based primary system under heavy primary traffic. To achieve spectrum sharing without degrading the performance of the primary system, the secondary transmitters alternate between cooperation and access modes based on a credit system. In the cooperation mode, the secondary transmitters serve as potential relays among which the best one is selected to help forward the primary packet, thus accumulating credits. These credits will then allow the secondary transmitters to gain spectrum access by exploiting the ARQ mechanism of the primary system.Our results show that with a cluster of closely located secondary transmitters, the proposed spectrum sharing protocol achieves an equal average throughput for the primary system compared to the case without spectrum sharing, while providing access opportunities for the secondary system. Furthermore, by increasing the number of secondary transmitters or decreasing the distance between secondary transmitters and secondary receiver, an overall higher throughput can be achieved for the secondary system, without affecting the analytical results for the upper bounds of primary throughput under cooperation mode, and secondary throughput under access mode are also derived.

Novel Design and Analysis of Aggregated ARQ Protocols for IEEE 802.11n Networks

The design of wireless local area networks (WLANs) with enhanced throughput performance have attracted significant amounts of attention in recent years. Based on the IEEE 802.11n standard, frame aggregation is considered one of the major factors to improve the system performance of 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 protocols are proposed to consider the effect from frame aggregation for the enhancement of network throughput. An aggregated selective repeat ARQ (ASR-ARQ) scheme is proposed which incorporates the selective repeat ARQ scheme with the consideration of frame aggregation. On the other hand, for worse channel quality, the aggregated hybrid ARQ (AH-ARQ) mechanism is proposed to further enhance the throughput performance by adopting the Reed-Solomon (RS) block code as forward error correction (FEC) scheme. Novel analytical models for both the ASR-ARQ and AH-ARQ protocols are established with the consideration of interfering wireless stations. Simulations are conducted to validate and compare the proposed ARQ mechanisms based on the service time distribution and system throughput. Numerical evaluations show that the proposed AH-ARQ protocol can outperform the other schemes under worse channel condition; while the ASR-ARQ scheme is superior to the other mechanisms under better channel condition.

Diversity-Multiplexing-Delay Tradeoff in Selection Cooperation Networks with ARQ

Selection cooperation is an attractive cooperative strategy for its simplicity and automatic repeat request (ARQ) mechanism can bring additional diversity benefit for wireless networks. In this paper, we combine the distributed selection cooperation protocols with ARQ mechanism to develop more powerful cooperative schemes for delay-tolerant wireless networks and analyze their performance from the perspective of diversity-multiplexing-delay (D-M-D) tradeoff. For small networks where any two nodes have direct links, we investigate the general ARQ scheme which directly extends the selection cooperation protocol with single round of feedback to multiple rounds. We show that the D-M-D tradeoff is determined by the ability of relays in signal combining and demonstrate that allowing relays to perform combining reception can achieve optimal D-M-D tradeoff. Then we propose a simplified scheme which greatly reduces the number of feedbacks and almost achieves the optimal performance. For large networks where direct links are limited in the neighbors of each node, we present a diffusion ARQ protocol which can effectively exploit the channels of nodes that have no direct links with the source. The D-M-D tradeoff analysis and simulation results demonstrate the significant performance improvement of all the proposed schemes.

Optimizing Selective ARQ for H.264 Live Streaming: A Novel Method for Predicting Loss-Impact in Real Time

This work proposes a quality-oriented, real-time capable prioritization technique for media units of H.264/AVC video streams. The derivation of estimates is based on the analysis of the macroblock partitioning, the spatial extents of temporal dependencies, and the length and strength of prediction chains existing among macroblocks, thus incorporating the expected impact of error propagation. It is demonstrated how the prioritization scheme can be beneficially integrated into live streaming systems which are characterized by tight timing constraints, with the focus on content-aware selective automatic repeat request mechanisms. Additionally, it is shown how potentially limited feedback can be used to adapt the estimation process to leverage prediction preciseness. The approach is compared against existing techniques in terms of practicability and efficiency, and tested under independent and bursty loss conditions in a wired and a wireless test setup. Moreover, the performance is examined when low-latency and constant bitrate video settings are enforced by using x264's novel encoding feature periodic-intra-refresh. Results of both experiments and simulations indicate that the proposed technique outperforms all reference techniques in nearly all test cases, and that the video quality can be further improved by incorporating receiver feedback.

Keys Through ARQ: Theory and Practice

This paper develops a novel framework for sharing secret keys using the Automatic Repeat reQuest (ARQ) protocol. We first characterize the underlying information theoretic limits, under different assumptions on the channel spatial and temporal correlation function. Our analysis reveals a novel role of “dumb antennas” in overcoming the negative impact of spatial correlation on the achievable secrecy rates. We further develop an adaptive rate allocation policy, which achieves higher secrecy rates in temporally correlated channels, and explicit constructions for ARQ secrecy coding that enjoy low implementation complexity. Building on this theoretical foundation, we propose a unified framework for ARQ-based secrecy in Wi-Fi networks. By exploiting the existing ARQ mechanism in the IEEE 802.11 standard, we develop security overlays that offer strong security guarantees at the expense of only minor modifications in the medium access layer. Our numerical results establish the achievability of nonzero secrecy rates even when the eavesdropper channel is less noisy, on the average, than the legitimate channel, while our Linux-based prototype demonstrates the efficiency of our ARQ overlays in mitigating all known, passive and active, Wi-Fi attacks at the expense of a minimal increase in the link setup time and a small loss in throughput.

A cooperative-ARQ protocol with frame combining

This article presents a low coordination overhead cooperative Automatic Repeat reQuest (ARQ) scheme with an integrated frame combiner, which exploits space diversity and cooperation between neighbouring nodes. A comparison between cooperation with and without frame combiner is also performed. In channels with a strong Line of Sight (LOS) component and low Signal-to-Noise ratio (SNR), the efficiency of the proposed protocol is many times higher than for other ARQ schemes. For non-LOS scenarios, the cooperative ARQ without frame combiner achieves the best efficiency results, and the overhead introduced by the frame combiner mechanism leads to results that can be even below the classical ARQ mechanism. In AWGN channels, the saturation throughput of the proposed scheme integrated into a IEEE 802.11 DCF based MAC is also studied. When the number of active stations is high, the cooperative ARQ without frame combiner shows to be the best option, while for light network loads, the presented scheme performs better.

Optimal Selection Criterion of the Modulation and Coding Scheme in Consideration of the Signaling Overhead of Mobile WiMAX Systems

An optimal selection criterion of the modulation and coding scheme (MCS) for maximizing spectral efficiency is proposed in consideration of the signaling overhead of mobile WiMAX systems with a hybrid automatic repeat request mechanism. A base station informs users about the resource assignments in each frame, and the allocation process generates a substantial signaling overhead, which influences the system throughput. However, the signaling overhead was ignored in previous MCS selection criteria. In this letter, the spectral efficiency is estimated on the basis of the signaling overhead and the number of transmissions. The performance of the proposed MCS selection criterion is evaluated in terms of the spectral efficiency in the mobile WiMAX system, with and without persistent allocation.

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.