Selective Repeat Protocol Research Articles

Performance analysis of TCP over visible light communication networks with ARQ‐SR protocol

ABSTRACTThis paper theoretically studies the performance of transmission control protocol (TCP) over visible light communications (VLC) networks when the automatic‐repeat request, selective repeat (ARQ‐SR) protocol is employed in the link layer. We analytically derive TCP throughput considering the impact of ARQ‐SR parameters and different VLC physical factors, including inter‐symbol interference (ISI), signal reflection and light power distribution. Numerical results show that TCP throughput is strongly dependent on the location of VLC user due to impacts of ISI and signal reflection. It is also seen that the use of ARQ‐SR could significantly improve both the maximum value and the distribution of TCP throughput in the VLC network. Especially, with a proper selection of the number of re‐transmissions by the ARQ‐SR protocol, the dependence of TCP throughput on user location caused by ISI, light signal reflection and distribution could be effectively remedied. Copyright © 2014 John Wiley & Sons, Ltd.

Data link layer of selective repeat protocol based on quantum teleportation

In this paper we study the quantum selective repeat protocol of data link layer based on quantum teleportation. When two sites are communicating in the physical layer, the sender divides a series of qubits intom frames by adding auxiliary qubits. After continuously transmitting m quantum frames, the receiver judges whether he receives the correct quantum frame according to the classical information provided by the sender. If the receiver receives the correct quantum frames, he returns confirmed frames using the quantum channel. If the correct quantum frames are not received, the receiver does not return denial frames. The sender judges quantum frames which he must resend according to the received confirm frames in setting time. Because the sender resends only the quantum frames which are lost or mistaken, this protocol reduces the transmission delay and improves communication efficiency. In the entire course of communications, the classical channel is used only to transmit the survey information, thus its burden is reduced.

Receiver buffer behavior for the selective repeat protocol over a wireless channel: An exact and large-deviations analysis

In this paper, we formulate and analyze a model of the resequencing buffer at the receiver's side for the Selective Repeat protocol over a general class of transmission channels. Thanks to its efficiency, Selective Repeat is a ubiquitous error control mechanism in many different settings, in particular in wireless protocols such as WiMax and WiFi.    In view of the correlated nature of transmission errors over wireless channels, the receiver buffer model considers a general Markovian error process. We provide both an exact mathematical analysis of the receiver buffer behavior as well as a computationally efficient large-deviations result. An asymptotic analysis of the delay is also given. Numerical examples show that the correlation of the error process has an important influence on the performance of the receiver buffer.

Timer expiration time of selective repeat protocol

Timer expiration times shorter than round-trip time are shown to possibly yield superior efficiency of selective repeat protocols, especially in the case of higher delay-bandwidth products and higher bit error rates. Both three-layer and two-layer communication system models are considered. A new timeout management strategy is proposed to be used in a two-layer system allowing a safe decrease of timer expiration time without the risk of inter-layer congestion. Simulation results confirm expectations, and the proposed strategy is compared with previously known multiple-copy transmission methods.

Link Layer Adaptation for Shared Wireless Links

While traditional link layer protocols assume that they fully control the underlying link, in contemporary wireless networks the link may be dynamically shared by sessions belonging to different users and/or applications. To assess the impact of link sharing, we measure the File Transfer and Web Browsing throughput achieved over a Selective Repeat (SR) protocol, with or without contention from Media Distribution. Our results indicate that the optimal protocol settings strongly depend on the level of contention for the link. We therefore present two link layer protocols that adapt to the available bandwidth, our Adaptive Selective Repeat (ASR) protocol which dynamically modifies its retransmission timeouts, and the Radio Link Control (RLC) protocol specified for use by Universal Mobile Telecommunications System networks which does not employ retransmission timers. We first repeat our performance measurements to determine the optimal settings for each protocol, and then compare the fine tuned versions of all protocols with respect to their File Transfer and Web Browsing throughput, as well as to the delay induced to the contending Media Distribution packets. Our results indicate that while both RLC and ASR are more stable than SR, the complex RLC does not match the performance of our simpler ASR.

Delay Analysis of the Selective-repeat ARQ Protocol with the Per-Flow Resequencing Scheme

An SR (Selective-Repeat) ARQ (Automatic Repeat reQuest) protocol is used to recover from packet errors effectively over a low-quality communication channel. This SR ARQ has a problem of large delay due to resequencing of received packets. To mitigate this problem, the PFRS (Per-Flow ReSequencing) scheme was proposed, where the resequencing is performed independently for each upper-layer flow, while detection of lost packets and associated retransmissions are performed on the basis of the whole flows multiplexed over SR ARQ. This paper models the SR ARQ protocol, where the maximum number of retransmissions is limited, by a collection of simple stop-and-wait protocols, and shows numerical calculation results for the delay distribution of retransmission and resequencing. The validity of the analysis is confirmed by comparing numerical calculations with simulation results. The results prove the effectiveness of the PFRS scheme for the case where the number of flows over SR ARQ is large.

Generalization of the basic sliding window protocol

A new protocol called generalized sliding window protocol is described and formally specified using the Specification and Description Language (SDL). The protocol generality was achieved by appropriately combining the classical go-back-n and selective-repeat protocols that both have traditionally been referred to as sliding window protocols. The proposed protocol is valid for any combination of send and receive window widths. The stop-and-wait, go-back-n and selective-repeat protocols are shown to be its special cases. Simulations show that the protocol efficiency initially increases with the increase of the receive window width, but can saturate or even reach its maximum value at a receive window width that is less than the send window width. This offers more freedom to choose a suitable compromise between buffer lengths and protocol efficiency, and an optimal efficiency may be achieved using less resources than with the selective-repeat protocol. The described protocol can serve as a starting point for the further development of new protocols, but can also be used as a simple, unified and theoretically sound protocol to be taught to telecommunications students. Copyright © 2004 John Wiley & Sons, Ltd.

Incremental Redundancy Hybrid ARQ Schemes Based on Low-Density Parity-Check Codes

We study the throughput of hybrid automatic retransmission request (H-ARQ) schemes based on incremental redundancy (IR) over a block-fading channel. We provide an information-theoretic analysis assuming binary random coding and typical-set decoding. Then, we study the performance of low-density parity-check (LDPC) code ensembles with iterative belief-propagation decoding, and show that, under the hypothesis of infinite-length codes, LDPCs yield almost optimal performance. Unfortunately, standard finite-length LDPC ensembles incur a considerable performance loss with respect to their infinite-length counterpart, because of their poor frame-error rate (FER) performance. In order to recover part of this loss, we propose two simple yet effective methods: using a modified LDPC ensemble designed to improve the FER; and using an outer selective-repeat protocol acting on smaller packets of information bits. Surprisingly, these apparently very different methods yield almost the same performance gain and recover a considerable fraction of the optimal throughput, thus making practical finite-length LDPC codes very attractive for data wireless communications based on IR H-ARQ schemes.

Generalised sliding window protocol

A new retransmission strategy of the basic sliding window protocol is proposed. The stop-and-wait, go-back-n and selective-repeat protocols are special cases of this generalised protocol. The protocol is correct for any combination of send and receive window widths. The protocol efficiency increases with the receive window width.

Point-to-multipoint SR ARQ scheme with accumulative acknowledgment for satellite communications

This paper describes and analyzes the performance of a reliable, finite-buffer, point-to-multipoint, selective repeat (SR) protocol with accumulative acknowledgment. It is simple to implement and suitable for high-speed data communications, mainly in satellite environments in which most of the time the channel bit error rate is very low and only occasionally becoming high. The proposed strategy is based on three key ideas. The first concept encompasses the use of accumulative acknowledgments in order to reduce the required processing overhead and implementation complexity, mainly in the transmitter. The second and third ideas are aimed at improving the throughput efficiency by making the most of the selective repeat recovery procedure (Go-Back(N) procedure is only employed when certain combinations of errors occur) and processing and storing all messages received correctly during an exceptional condition, even after error detections. The proposed strategy performs well under various conditions being more efficient than most known point-to-multipoint GB(N) strategies for low bit error rates.

Analysis and optimization of adaptive multicopy transmission ARQ protocols for time-varying channels

This paper outlines an efficient method to concurrently optimize a multiplicity of design variables for continuous selective-repeat (SR) and go-back-N (GBN) automatic repeat request (ARQ) strategies, both in noiseless and noisy feedback channels. For these ARQ protocols, we adapt either the number of identical message blocks sent in each transmission (in the case of GBN scheme) or the number of copies of a block retransmitted to handle a NACKed codeword (for the SR protocol) dynamically to the estimated channel condition. The channel state information is obtained by counting the contiguous acknowledgment (ACK or NACK) messages. Exploiting the asymptotic properties of the steady state probability expressions, we show analytically that the optimum solution indeed lies in the infinite space. Subsequently, a simple expression to estimate the suboptimal design parameters is suggested. Our approach of minimizing the mean-square error function yields to a quantitative study of the appropriateness of the selected parameters. Exact analytical expressions that allows us to compute the throughput crossover probability between any two arbitrary multicopy transmission modes are derived. The results provide fundamental insights into how these key parameters interact and determine the system performance.

Performance analysis of an improved selective repeat protocol for high-speed networks

In this paper, we introduce a new error recovery protocol which minimizes the number of control packets required to achieve reliable communication. The proposed protocol adapts itself to work efficiently during congestion. A complete analysis of the performance of the proposed protocol is presented. The analytical and simulation results of the proposed scheme illustrate high throughput and limited cell delay which can be achieved with a small number of control cells.

Throughput of selective-repeat ARQ with time diversity in Markov channels with unreliable feedback

In this paper, a modified form of the ARQ selective repeat protocol with timer control is studied. Transmissions on both the forward and the reverse channels are assumed to experience Markovian errors and therefore the feedback is unreliable. Feedback error recovery is made possible through the use of time diversity.Using results from renewal theory, exact results for the throughput of the protocol are evaluated. In order to overcome the complexity of the exact analytical technique, lower and upper bounds are developed. Simulation results, that confirm the analysis and document the tightness of the bounds are also shown, and a number of implementation issues are discussed. An application to mobile radio is also presented.It is shown that the use of an appropriate degree of time diversity makes it possible to approach the ideal protocol performance obtained with perfect feedback.

An improved selective repeat protocol and its performance in high-speed environments

In this paper, we present a new selective-repeat ARQ strategy named High-Speed Selective-Repeat (HSR) protocol which provides a very fast error recovery mechanism. Unlike other selective repeat strategies, this strategy ensures that a correctly received packet will not be retransmitted. In addition, this protocol is simple enough that it places little computational load on the transmit and receive processes. Analysis of this protocol indicates that it performs close to an ideal selective-repeat if its parameters are adjusted properly. The analysis is performed by means of analytical techniques. Analytical results are used to study the performance measures through numerical examples. The results provide insights into the interaction between the protocol parameters and identify the operational characteristics.

Dynamic programming for optimization of system throughput with application to selective-repeat ARQ protocols over broadcast channels

This paper studies packet network data link layer error control protocols suitable for point-to-multipoint communication. We optimize the throughput performance of two new selective-repeat protocols which differ in the way the sender uses the outcomes of the previous transmission. In both protocols, multiple copies of a data frame are sent (instead of just a single copy). The optimum number of copies is determined based on how many receivers have not yet received the data frame. A dynamic programming technique is used to solve this optimization problem. The results show that by sending the optimum number of copies of a data frame instead of just a single copy, the throughput will be significantly improved.

Throughput estimation of ARQ protocols for a Rayleigh fading channel using fade- and interfade-duration statistics

Error detection combined with automatic repeat request retransmission is used to provide reliable digital data transmission over a communication channel. The throughput for a system using go-back-N or selective-repeat protocols with Rayleigh fading in both directions of transmission is approximated by using fade- and interfade-duration statistics of a multipath channel. Results indicate that for a slow-fading channel (e.g. fading rate=1.34 Hz), the throughput of go-back-N is only slightly inferior to that of selective-repeat, mainly due to the burstiness of the channel bit errors. >

A go-back-N protocol for mobile communications

The author describes a go-back-N (GBN) protocol, which is a type of automatic repeat request (ARQ) technique. The protocol has a buffer and memory at the receiver side and offers low implementation complexity and a structure especially suited to mobile communications. The optimization of the protocol parameters is determined through numerical analysis. Performance is evaluated by computer simulation using a channel model suitable for mobile communications. The results show that the proposed ARQ scheme achieves a higher performance than that of other ARQ protocols and that at high error rates its efficiency compares favorably with selective repeat protocols having an infinite buffer.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Comparison of two ARQ protocols in a Rayleigh fading channel

Go-back-N (GBN) and selective repeat (SR) protocols for automatic repeat request (ARQ) are compared in a frequency-nonselective Rayleigh fading channel. Protocols implemented in software are used in a computer-simulated fading channel to study the throughput of these protocols as a function of fading parameters, such as the mean signal-to-noise ratio (SNR), maximum Doppler frequency number of diversity branches, time-out period and round-trip delay. The purpose is to complement well-documented theoretical work in (1) providing some design considerations and (2) investigating quantitatively whether data communications combining detection-only coding, diversity, and basic ARQ protocols can offer reasonable throughput in a fading channel. Although based on a set of assumptions, the following conclusions remain valid: (1) SR is significantly superior to GBN when the fading rate is high; this advantage decreases as fading becomes slower; and (2) error detection combined with ARQ and diversity selection can provide reliable data communications in a Rayleigh fading channel.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Evaluation of retransmission strategies in a local area network environment

We present an evaluation of retransmission strategies over local area networks. Expressions are derived for the expectation and the variance of the transmission time of the go-back-n and the selective repeat protocols in the presence of errors. These are compared to the expressions for blast with full retransmission on error (BFRE) derived by Zwaenepoel [Zwa 85]. We conclude that go-back-n performs almost as well as selective repeat and is very much simpler to implement while BFRE is stable only for a limited range of messages sizes and error rates. We also present a variant of BFRE which optimally checkpoints the transmission of a large message. This is shown to overcome the instability of ordinary BFRE. It has a simple state machine and seems to take full advantage of the low error rates of local area networks. We further investigate go-back-n by generalizing the analysis to an upper layer transport protocol, which is likely to encounter among other things, variable delays due to protocol overhead, multiple connections, process switches and operating system scheduling priorities.