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SUMMARY Hybrid automatic repeat request (HARQ) and automatic repeat request (ARQ) of the terrestrial long-term evolution (LTE) system are designed considering the very short propagation delay of terrestrial environment. Therefore, when HARQ and ARQ are applied to the LTE-based mobile satellite communication system, the inefficiency is caused by the long propagation delay of satellite environment. This paper proposes the interaction method between HARQ and ARQ for the decrease of inefficiency in the LTE-based mobile satellite communication system. The existing concept of layered architecture about HARQ and ARQ is also maintained in our interaction method. Simulation results reveal that our proposed scheme can provide the larger spectrum efficiency than that of the non-interaction scheme in all environments. The performance improvement can be up to 2.04 times through the interaction method. Copyright © 2014 John Wiley & Sons, Ltd.

Wireless networks are being increasingly employed to provide mobile access to network services. In most existing standards, reliable transmission on the wireless medium is achieved through the introduction of ARQ schemes at MAC layer, a strategy which is also employed by TCP for reliable end-to-end data delivery. The paper proposes an approach to overcome the performance degradation deriving from the duplicate ARQ strategies implemented at the transport and MAC layers by introducing a cross-layer solution to reduce un-necessary transmissions on the wireless medium. Furthermore, the paper describes how the proposed scheme, called ARQ Proxy, can be deployed in three different wireless technologies (3G Long-Term Evolution, Wi-Fi, and WiMAX) and provides extensive validation of the achievable improvement through simulations. Copyright © 2011 John Wiley & Sons, Ltd.

In this paper, we evaluate the performance of the hybrid automatic repeat request (ARQ) scheme combined with adaptive coding in satellite communication systems. A cross-layer design which combines the ARQ scheme in the data link layer and adaptive coding and modulation in the physical layer is very important to maximize system throughput and/or performance. Due to the long round trip delay in satellite systems, the strategy to adopt may need to be different from that is used in the terrestrial systems. A rate compatible code is a desirable scheme for adaptive coding and hybrid ARQ. In this paper, we propose an adaptive coding scheme with hybrid ARQ using rate compatible block turbo codes, and demonstrate its performance on a mobile satellite channel for multimedia applications. The proposed rate compatible block turbo codes are a very effective tool to improve the performance of satellite systems using adaptive coding with hybrid ARQ. The simulation results presented in this paper reveal that the hybrid ARQ scheme combined with adaptive coding can improve the system performance by effectively compensating for the various channel attenuations. Copyright © 2006 John Wiley & Sons, Ltd.

Based on highly reliable data transmission, we previously proposed a Go-Back-N ARQ scheme with selective repeat in intra-block, where the receiver returns the acknowledge signal in the unit of a block composed of multiple frames, with the aim of reducing the network traffic and the objective of effectively processing the frames. This paper considers the traffic characteristics when the number of block retransmissions in a Go-Back-N ARQ scheme with selective repeat in intra-block is limited. In this scheme, blocks composed of multiple frames which contain information with some correlation as in images are transmitted. If the retransmission of a block reaches the preset limit, the receiver accepts that block even if erroneous frames are included, and the errors are processed as noise or distortion. Therefore, an upper bound can be set for the time elapsed from the start to the end of the block transmission. We theoretically analyze the system considered and derive the throughput, the average transmission delay of a block, and the average transmission delay with the condition of the number of transmissions. The traffic characteristics are investigated from numerical examples using analytical results. We show that the throughput performance and average transmission delay performance are improved by limiting the number of retransmissions. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(3): 64–73, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20311

This paper considers the selective-repeat ARQ scheme, which is a typical error control scheme used in data communication systems, and analyzes the performance of the scheme in which the number of frame retransmissions is limited. In the proposed scheme, messages such as image for which information loss can be tolerated to some extent are transmitted after being divided into multiple frames. If the retransmission of a frame reaches the preset limit, the receiver accepts that frame even if an error is present, and the error is processed as noise or distortion. By this scheme, an upper limit can be defined for the time from the start to the end of the message transmission. This paper analyzes the proposed scheme using the discrete-time queuing model and derives the distribution of the message transmission delay. The throughput and the required receiver buffer capacity are also derived. It is shown by numerical examples that the throughput can be improved and the receiver buffer capacity can be reduced. If the strict analysis is continued, however, the state space of the Markov chain is enlarged with the increase in the number of parameters such as the round-trip propagation delay and the number of message divisions. Thus, the numerical calculation of the transmission delay becomes difficult. The approximate analysis of the message transmission delay and its properties are discussed in Ref. 1. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(6): 1–11, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10181

It is known that the performance of a single-receiver ARQ scheme strongly depends on the packet error generation process. Hence, it is not possible to use results assuming independent (or random) packet errors for performance evaluation of the ARQ scheme in an environment of nonindependent (or burst) packet error generation. This also applies to the performance of the multireceiver ARQ scheme. However, performance evaluation of the multireceiver ARQ scheme has not been carried out in an environment of nonindependent packet error generation. In the present paper, the throughput efficiency of the basic multireceiver Go-Back-N ARQ scheme that can be applied when a transmission station sends identical data to the receivers connected to each of multiple parallel channels is derived for the environment of burst packet error generation according to mutually independent two-state Markov processes. Further, numerical examples based on the derived results are presented and the effect of the number of receiving stations, the round-trip delay, and the nature of the Markov process on the throughput efficiency is obtained. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(9): 34–42, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10073

Infrared wireless LANs may employ repetition rate (RR) coding to increase the symbol capture probability at the receiver. This paper examines the effectiveness of RR coding to utilization for infrared LANs using the physical and link layer parameter values proposed in the Advanced Infrared (AIr) protocol standard, which is developed by the Infrared Data Association (IrDA). Infrared LANs employ a Go-Back-N (GBN) automatic repeat request (ARQ) retransmission scheme at the Link Control (LC) layer to ensure reliable information transfer. To efficiently implement RR coding, the receiver may return after every DATA packet a suggestion for the suitable RR value to be used by the transmitter and implement a Stop-and-Wait (SW) ARQ scheme at the medium access control (MAC) layer. The effectiveness of employing this optional SW ARQ scheme at the MAC layer is discussed. Analytical models for the ARQ retransmission schemes are developed and employed to compare protocol utilization for different link parameter values such as window size, packet length and LC time out periods. This analysis identifies the ARQ protocol that maximizes performance for the specific link quality and the implemented link layer parameters. The effectiveness of the proposed RR coding to LAN utilization for different ARQ scheme implementation is finally explored. This analysis identifies the link quality level at which RR should be adjusted for maximum performance. It is concluded that if the packet error rate is higher than 0.1–0.4 (depending on the implemented ARQ protocol), the receiver should advise the transmitter to double the implemented RR for maximum performance. These error rate values are high and can be effectively estimated by the transmitter based on packet retransmissions. Thus, the usefulness of the receiver indicating to the transmitter to adjust RR is questionable, as the transmitter can effectively implement the suitable RR value based on packet retransmissions. Copyright © 2003 John Wiley & Sons, Ltd.

This paper discusses the traffic characteristics of the Go-back-N (GBN)_SR scheme, in which the receiver returns the acknowledge signal blockwise and selective repeat is performed within the retransmission block. First the strict expression for the throughput and the strict expression for the average transmission delay of the blockwise bulk arrival model are derived. Then, the throughput of the GBN_SR scheme and the average transmission delay of the blockwise bulk arrival model are examined by numerical calculation. The average transmission delay of the packetwise bulk arrival model is investigated by simulation. It is shown that the throughput is improved with increasing block size, and that the average transmission delay can be minimized by using the optimal block size, depending on the average packet error rate and the block arrival rate. It is also shown for the packetwise bulk arrival model that there exists a block size which minimizes the average transmission delay, and that the minimum average transmission delay is smaller than in the blockwise bulk arrival model. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(3): 9–16, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ ecja.10052

Combined error correction and detection techniques, or hybrid automatic-repeat-request (ARQ) schemes with negative acknowledgment are considered for highly reliable reverse link data transmission in direct sequence code division multiple access (DS-CDMA) personal communication systems. The proposed selective repeat hybrid ARQ scheme employs an inner convolutional code for error correction and an outer shortened BCH code for error detection. Each negative acknowledgment message contains all packet sequence numbers that have been detected in error, and it is both error-correction and error-detection encoded. Accepted packet error rate and throughput are derived as a function of the error correction encoded frame error rate. An optimum signal-to-interference ratio (SIR) assignment maximizing the system's capacity is also found. A comprehensive simulation is conducted to evaluate performance of the data transmission system. Analysis and simulations show that by applying the proposed type I hybrid ARQ scheme with properly selected system parameters, virtually error free and highly efficient data transmission in CDMA personal communication systems is possible.

Automatic repeat request (ARQ) is very effective in error control, and among various ARQs, selective repeat gives the best throughput characteristics where infinite-capacity buffers are theoretically required in the transmitter and receiver stations. Therefore, in practice, a modified selective repeat request method with a finite-capacity buffer must be devised. In this paper, a selective repeat method is proposed where multiple frames corresponding to a message may continuously be sent. Based on the error rate, number of repeats, and round-trip delay time, the appropriate number of multiple transmissions for maximum throughput in the case of a finite-capacity buffer is derived. It is shown that good throughput characteristics can be achieved in the proposed method with an appropriate number of multiple transmissions. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 84(6): 68–76, 2001

In ATM networks, when cells are lost due to congestion, packets containing the lost cells should be retransmitted in the transport layer, which manages the end-to-end communication. The probability that a packet contains at least one lost cell depends on the packet length. It is thus very likely that the performance of the end-to-end communication is influenced by the packet length. In this paper, we analyze the packet loss probability and the maximum achievable throughput when a block of data is divided into packets of fixed size and the lost packets are retransmitted based on the selective repeat ARQ. Through the analysis, we examine the effect of the packet length and the peak cell transmission rate on the performance measures.

The channel in the intensity modulation-direct detection (IMDD) system, which is one of the typical optical communication systems, can be modeled as a Z-channel, where only “1-to-0” errors are produced. Consequently, by applying the all-unidirectional error-detecting code, error-free communication can be realized by using an ARQ (Automatic Repeat Request) scheme in which the codeword containing errors is retransmitted. From such a viewpoint, this paper discusses the application of a hybrid ARQ scheme to optical communications. First, the throughput is used as the evaluation measure. It is shown that the hybrid ARQ scheme (hybrid SR+GBN ARQ scheme), which combines a single-error correction/all-unidirectional error detection code (SEC/AUED code) with the selective Go-Back-N method is the ARQ scheme most suited to the optical communication from a practical viewpoint, including the fact that it can be realized using a receiver buffer with finite length. We propose an SEC/AUED code that allows coding/decoding with practicable computational complexity, even if the code length is great. The performance is evaluated for the hybrid SR+GBN ARQ scheme. It is shown that a throughput exceeding 99.8% can be realized if the error rate of the channel is less than 10−6. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 3, 80(3): 73–82, 1997

It is generally impossible to avoid occurrences of errors of the data transmission because of the disturbing factors such as disconnections, noises or distortions in a communication line. Therefore, the error-control procedure is indispensable to trnnsmit high-quality data and its various techinques have been considered from the viewpoints of high reliability data transmission. the main techniques in the error-correcting strategies are classified into the following three categories: (i) forward-error-correction (FEC) scheme; (ii) automatic-repeat-request (ARQ) scheme; and (iii) hybrid ARQ scheme. the hybrid ARQ scheme is the system combined FEC scheme with ARQ scheme. This aims to reduce the frequency of retransmissions as much as possible and to gain a constant data throughput, even in a worse communication environment, by coding error patterns that would be expected to occur frequently. However, when the first data of transmission has failed, the hybrid ARQ is removed to the ARQ policy with the same FEC, i.e., its data throughput decreases because of bit increments, such as codes to correct errors in the data transmission. This is called type-I hybrid ARQ and its modified systems, which are called type-II hybrid ARQ, have been studied and proposed by many authors. This paper suggests a new type-II hybrid ARQ system from the viewpoint of improving the data throughput and derives the mean time to success of the data transmission. Then, the mean times of the system are compared analytically with those of the usual ARQ and the type-I hybrid ARQ, and an evaluation is done.

Automatic repeat request (ARQ) techniques with error-detecting codes are commonly used in communication systems. Of these, selective protocols, while the most efficient, have the notable drawback of requiring large buffers at the receiver side. A new selective ARQ protocol with a finite-length buffer is described in this paper. If N is the number of codewords transmittable in the round-trip delay, the described protocol requires a buffer having length equal to N + N a , N a ≥ 2 being an integer. A lower bound on the throughput of the described ARQ protocol is derived. The proposed protocol achieves higher throughputs than similar schemes, giving comparable results to selective protocols with infinite-length buffers for high error rates in the communication channel.

The transmission delay and throughput performances of a hybrid Go-Back-N automatic repeat request (ARQ) scheme are analyzed. In the hybrid scheme, multiple alternate transmissions of the copy and parity block of each data block are repeated continuously by transmitter. The receiver detects or corrects errors in a received block by using Wang and Lin's error control algorithm. It is shown that we can obtain the optimum total number of continuous transmissions of copies and parity blocks, which minimizes the average delay time and maximizes the throughput.

The optical communication system can provide highly reliable and large-capacity transmission. It is becoming important as the major technology of highspeed digital communication. In the optical communication system, even though it is highly reliable, inevitably the bit error rate is deteriorated with the increase of the transmission rate or the repeater distance. It is anticipated that some methods of error control will be required in the future. This paper discusses the application of the automated repeat request (ARQ) scheme, which is one of the error control methods, to the optical communication. It is noted first that the error that occurs in the optical communication channel is the transition from symbol 1 to “0,” but it can never be the transition from “0” to “ 1.” An ARQ scheme is proposed using the m-out-of-n code which can detect any error in such a channel. A performance evaluation is presented based on the throughput and the information efficiency per photon. It is shown as a result that the SR-M3BN scheme is the best among various ARQ schemes from the practical viewpoint. It combines selective-repeat (SR) and go-back-N (GBN). Then a new error-detecting scheme is proposed based on the characteristics of the optical channel, which can reduce the number of repeats of the codeword. It is shown that, by combining the proposed scheme with SR+GBN, a higher throughput can be achieved.

Hybrid forward error correction/automatic-repeat request (FEC/ARQ) systems achieve greater throughput than ARQ systems by combining forward error correction with automatic-repeat requests. A type-II hybrid FEC/ARQ system is capable of adapting error-correction capacity according to varying channel conditions. Although a high throughput can be achieved in such systems by using conventional convolutional or rate compatible punctured convolutional (RCPC) codes, when the channel signal-to-noise ratio (SNR) Es/N0 is low, resulting throughput efficiency and mean block delay performances are unsatisfactory. In this paper, selective repeat type-II hybrid FEC/ARQ systems using concatenated codes are proposed to improve the throughput efficiency and mean block delay performances on channels with low SNRs. Systems using concatenated Reed-Solomon outer codes and either rate one-half convolutional or rate compatible convolutional (RCPC) inner codes are evaluated. The throughput efficiency and mean packet waiting and block delay times of these two types of concatenated coding systems are evaluated. A theoretical analysis and computer simulation of throughput efficiency of the proposed systems show increased performance for a wide range of Es/N0 over previous systems that use either stand-alone rate one-half convolutional or RCPC codes. It is also shown that the transmitter mean packet queueing delay and mean block delay times are reduced. In particular, by computer simulation, it is shown that when the traffic density is high, mean block delay times are greatly reduced by the use of RCPC inner codes.

An automatic-repeat-request (ARQ) scheme with memory is described in which the received vectors, even when detected in error, are retained to facilitate the correct recovery of the transmitted message. The optimization of the system parameters with the transmission channel affected by fading have been derived theoretically. The results of computer simulations performed to evaluate throughput show considerable improvement with respect to the classical ARQ protocols, making the proposed scheme especially suitable for mobile communications.

In land mobile data transmission, the error control by FEC and ARQ generally is employed to improve the reliability of transmission. In the control signal transmission for the radio link control in the mobile communication system, the error usually is detected by FEC, and the reliability is improved by ARQ. Under the condition of motion velocity of 40 to 50 km/h and the tolerable transmission delay of several seconds, the transmission characteristics of ARQ depend greatly on the short-term median variation of the received level of the retransmitted signal, together with the packet signal transmission characteristics under the instantaneous received level variation due to fading. No evaluation has been presented for the transmission characteristics of ARQ considering such a median variation. This paper considers the stop-and-wait (SAW) ARQ where the number of retransmissions is limited to a finite value, and presents an evaluation of the transmission characteristics considering the correlation of the short-term median variation of the retransmitted signal. Numerical examples are presented. Assuming that SAW-ARQ is applied to the transmission protocol of the common control channel, the blocking probability is examined, together with numerical examples.

The go-back-N scheme is one of the error control methods in the satellite link. Various improvements have been made on this scheme, and the resulting throughput characteristics and packet delay characteristics have been described. However, in those methods, the priority of the class of the packet to be transmitted is not considered. This paper discusses the go-back-N scheme where priority rules are useful when several packets with different priority classes are to be transmitted on the satellite link are introduced. Two priority rules are introduced: nonpreemptive priority queueing and preemptive priority queueing. The go-back-N ARQ scheme with those priority rules can easily be realized by adding the packet sort function to the transmitter buffer in the conventional basic go-back-N ARQ scheme. The traffic analysis is made of the go-back-N ARQ scheme with those two priority rules for an arbitrary number of priority classes, and the packet delay expression is derived for each class. Then by numerical calculation examples, the average packet transmission delay characteristics in the two methods are examined.

In this paper a new protocol suitable for communication systems using error detecting codes is described. This scheme is similar to a Go-Back-N protocol, but it presents higher performance. The throughput of the protocol is determined through a theoretical analysis. The results show that the proposed protocol maintains, as the Go-Back-N schemes, a simple implementation structure, but at the same time permits to achieve high throughput values. In particular, for high error rates in the communication channel the described protocol achieves performance comparable with that of the selective protocol with infinite buffer.

Adaptive ARQ (automatic repeat request) is an error-control scheme in data transmission in which the number of successively transmitted data blocks and the data block length are adjusted according to the bit error rate. This scheme performs better in half-duplex transmission than the conventional selective repeat (SR) and go-back-N (GBN) schemes when the bit error rate is either not known or varies with time. This paper proposes a control procedure for the full-duplex adaptive ARQ scheme. In this procedure an observation period is defined and the data block length is adjusted dynamically according to the success of the data block transmission in the observation period. The throughput of this scheme is analyzed. The proposed scheme is compared with nine conventional schemes, including SR and GBN, in terms of performance. The results indicate that the performance of the adaptive ARQ scheme is very close to that of the fixed data block scheme in which the optimal data block length is selected statically. It is also shown that the performance of the adaptive ARQ scheme does not degrade as rapidly as in other schemes when the bit error rate increases.

The performances (throughput and transmission delay) of the Go-back-N ARQ scheme are affected greatly by the bit error rate of the link and the round-trip propagation delay. This paper discusses the transmission delay of the tandem Go-back-N scheme, in which the round-trip propagation delay can substantially be reduced. First, the generating function for the transmission delay distribution is derived, and then the result is applied to derive the average transmission delay. As a result, it is shown clearly that the performance of the tandem Go-back-N ARQ scheme is better than that of the standard Go-back-N ARQ scheme.

Some new hybrid ARQ schemes for error control in communication systems are presented in which redundancy, achieved by retransmission of a code word, is exploited to facilitate correct code-word recovery. In the first two techniques, applicable to cases in which a code word detected in error is retransmitted several times consecutively, an error-correcting code is used in conjunction with a normal ARQ code to enhance performance even at high error rates. These two techniques have been modified to allow application to protocols in which only one copy is sent each time a code word must be transmitted. Theoretical analysis of the protocols shows that these techniques outperform similar ARQ schemes, particularly for high error rates.

ARQ (Automatic Repeat Request) schemes are methods for controlling the error in data transmission. Among the schemes previously proposed are the selective repeat, the GO-BACK-N, and the combinations as well as the modifications of these schemes. The analysis of these schemes has been performed on the basis of a simplified model. This paper presents the analysis of several ARQ schemes using a more complex model which takes into account the long propagation delay (such as satellite links), transmission delay associated with retransmission, the system internal time, and the buffer size of the sending station. A concept of equivalent channel holding time is used in conjunction with a M/G/1 queueing model for the analysis of the system throughput as well as other characteristics.

It is known that by applying a soft decoding algorithm to the error-detecting code in the ARQ system, a hybrid ARQ system can be realized in which error detection and correction are possible. This paper discusses the application of the soft decoding algorithm to the ARQ system, where the multivalued digital modulation is employed. A scheme for a practical system is proposed, including the detection of channel measurement information in the multivalued digital modulation system and estimation of error patterns. By the proposed method, the hybrid ARQ system can easily be realized by adding some peripheral circuits to the conventional ARQ receiver. Theoretical study is made on the number of error patterns that can be estimated for a long block length as well as the probability of miss and the probability of retransmission request. The proposed scheme was applied experimentally to the ARQ system employing SG VIII V.29 modem based on CCITT recommendation, and the usefulness of the proposed scheme was verified by experiment.

This paper describes the development of a laboratory test unit that implements a new Type I/II ARQ scheme for use on a land mobile forward satellite link. Investigation of channel characteristics showed that it was possible to use convolutional coding to combat random errors, but it was also necessary to employ an ARQ scheme in order to overcome fades due to signal blockage. The hardware development used commercial 68000-based VME cards as well as special-purpose cards to perform the functions of Viterbi decoding and packet synchronization. Results are presented for the hardware operating with Gaussian noise as time limitations excluded the use of satellite fading simulation. In order to ensure a high degree of data integrity error detection was applied to the data packets such that a residual error rate of less than 10−11 should result. This was not able to be verified due to the limited time. However, long term tests did indicate that an error rate less than 10−8 was achieved.