Forward Correction and Fountain Codes in Delay-Tolerant Networks

Computing Research Repository, 2006

In this paper, we investigate the delay-throughput trade-offs in mobile ad-hoc networks under two-dimensional i.i.d. mobility models. We consider two mobility time-scales: (i) Fast mobility where node mobility is at the same time-scale as data transmissions; (ii) Slow mobility where node mobility is assumed to occur at a much slower time-scale than data transmissions. Given a delay constraint $D,$ the main results are as follows: (1) For the two-dimensional i.i.d. mobility model with fast mobiles, the maximum throughput per source-destination (S-D) pair is shown to be $O(\sqrt{D/n}),$ where $n$ is the number of mobiles. (2) For the two-dimensional i.i.d. mobility model with slow mobiles, the maximum throughput per S-D pair is shown to be $O(\sqrt[3]{D/n}).$ (3) For each case, we propose a joint coding-scheduling algorithm to achieve the optimal delay-throughput trade-offs.

IEICE Transactions on Communications, 2017

Delay Tolerant Networks (DTN) protocols based on the store-andcarry principle offer useful functions such as forwarding, utility value, social networks, and network coding. Although many DTN protocol proposals have been offered, work continues to improve performance. In order to implement DTN functions, each protocol introduces multiple parameters; their performance is largely dependent on how the parameter values are set. In this paper, we focus on improving spray and wait (S&W) by proposing a communication protocol named a Spray and AHP-GRA-based Forwarding (S&AGF) and Spray and Fuzzy based Forwarding (S&FF) scheme for DTN. The proposed protocols include a new forwarding scheme intended to extend network lifetime as well as maintain acceptable delivery ratio by addressing a deficiency in existing schemes that do not take energy into consideration. We choose the most suitable relay node by taking the energy, mobility, measured parameters of nodes into account. The simulation-based comparison demonstrates that the proposed S&AGF and S&FF schemes show better balanced performance level in terms of both delivery ratio and network lifetime than original S&W and its variants.

2011 11th International Conference on ITS Telecommunications, 2011

In this paper we propose a data dissemination technique based on Fountain codes, that is particularly suitable for vehicular environments, where mobility and connectivity issues often occur. We investigate the reliability of a real-time service and data delivery for multicast transmission over lossy Vehicular Ad-hoc NETworks (VANETs). The proposed technique represents the next work of a previous approach initially applied to traditional Mobile Ad-Hoc NETworks (MANETs). This technique combines application layer channel coding based on Luby Transform (LT) codes with multicast delivery in a wireless network exploiting PUMA (Protocol for Unified Multicasting through Announcements). The main goal is to achieve a real-time service with an high quality level in a lossy vehicular network environment. The rateless property, the ability of adapt the code on-the-fly, makes Fountain codes an attractive solution for data broadcast/multicast applications, like the well-known comfort applications. In a VANET scenario characterized by dynamic topology conditions, packet losses and disconnections, the proposed approach leads to an improvement on arrival times of packets towards destination vehicles. Simulation results provide the effectiveness of our technique compared with traditional data dissemination approach.

… Congress (ITC), 2011 …, 2011

We propose a new reliable transport scheme for Delay Tolerant Networks (DTNs) based on the use of acknowledgments (ACKs) as well as coding. We, specifically, develop a fluid-limit model to derive expressions for the delay performance of the proposed reliable transport scheme and derive the optimal setting of the parameters which minimize the file transfer time. Our results yield optimal values for the number of outstanding random linear combinations to be sent before time-out as well as the optimal value of the time-out itself, ...

2015

17 Abstract— Broadcast and multicast operations which disseminate information network wide are important features in multi-hop wireless networks. This work shows how network coding can be applied in wireless in ad hoc networks. We focus on broadcast traffic and design a network coding-based scheme that we compare against simpler solutions, through extensive simulations. Our goal is to assess the performance of the proposed network coding scheme in wireless ad hoc networks in both realistic MAC and physical are considered and when mobility of nodes is considered as well. The performance analysis of the proposed network coding scheme on broadcasting traffic is strongly depends on the network node density and the generation size. Network coding brings no benefits to be implemented and run in sparse networks. On the other hand, network coding performs well and has significant gains in terms of end-to-end packet loss probability in dense networks. Moreover, achieved results show that the...

2006 3rd Annual IEEE Communications Society on Sensor and Ad Hoc Communications and Networks, 2006

We consider multi-hop transmission from the source to the destination in ad-hoc wireless networks. Cooperative forwarding approaches in the framework of progressive network coding are proposed which generalize coded cooperation in a multi-hop context. In this framework, the source node and each succeeding relay node progressively decode what they receive from the previous stages and re-encode the messages to different parts of the parity bits from a single (network) codeword hop by hop. The maximal achievable rates for the multi-hop wireless networks using traditional repetition-forward and progressive network coding are analyzed with respect to different transmit power constraint and packet length allocation. The optimal number of relays are derived in each scheme. It is found that progressive network coding with adaptive packet length significantly increases the system throughput and improves the energy efficiency.

Lecture Notes in Computer Science, 2013

We consider the data delivery problem in delay tolerant networks, where a data content is located in a fixed source need to be delivered to a specific destination. We assume nodes have limited storage and computational capabilities. In this paper, we initially, explore the data delivery problem, for both unbiased and biased contact models. Based on our observations, we propose a data delivery scheme that can reduce both storage overhead and delivery delay. Our scheme combines erasure coding technique and the framework of simulated annealing optimization, in order to maximize the content delivery probability to the destination.

International Journal of Computer Applications, 2014

Network coding has recently emerged as an effective solution for multicast and broadcast communications in ad hoc networks. We focus on broadcast traffic and design a network coding-based scheme that we compare against simpler solutions, through extensive simulations in the ns-2 network simulator. Indeed, while often the benefits of network coding have been shown via theoretical analysis or in simplified simulation scenarios, our aim is to assess the performance of network coding in ad hoc networks when realistic MAC and physical layers are considered. The performance of network coding for traffic broadcasting strongly depends on the network node density and on the generation size. In particular, network coding fails to work in sparse networks, where connectivity is low, and leads to significant gains in terms of end-to-end packet loss probability in dense networks, where congestion is likely. It requires neither a global nor a partial view of the network, nor does it require information about neighboring nodes. Moreover, achieved results show that the protocol delivers broadcast data reliably with minimal network overhead, by eliminating redundant data transmissions, even under adverse network conditions.

2010

Abstract Routing in delay tolerant networks (DTNs) in which most of the nodes are mobile and intermittently connected is a challenging problem because of unpredictable node movements and lack of knowledge of future node connections. To ensure reliability against failures and increase the success rate of delivery, erasure coding technique is used to route messages in DTNs. In this paper, we study how the cost of erasure coding based routing protocols can be reduced.

IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, 2011

This paper concentrates on the proper use of fountain codes for the transmission of sporadic data in a wireless sensor network (WSN). Fountain codes offer great perspectives for the self-organization of WSNs: they self adapt to the channel error rate without control packets. Deploying fountain codes in a WSN raises two problems. First, the size of the data transmitted by a sensor is small in comparison to the size usually considered with fountain codes. Second, WSNs mostly rely on multi-hop transmissions. It implies a non null transmission duration for the end-to-end acknowledgement of the reception. During this period of time, the source is still transmitting useless packets, creating a specific overhead we define as the overflow. This paper brings the overflow problem to light and analyses its impact on the network performance. Our work can be viewed as the networking counterpart of the results presented by Pakzad et al. at ISIT 2005 applied to WSNs.

Ad Hoc Networks, 2013

We propose and study a new set of enhancement features to improve the performance of reliable transport in Delay Tolerant Networks (DTNs) consisting of both unicast and multicast flows. The improvement in reliability is brought in by a novel Global Selective ACKnowledgment (G-SACK) scheme and random linear network coding. The motivation for using network coding and G-SACKs comes from the observation that one should take the maximum advantage of the contact opportunities which occur quite infrequently in DTNs. Network coding and G-SACKs perform "mixing" of packet and acknowledgment information, respectively, at the contact opportunities and essentially solve the randomness and finite capacity limitations of DTNs. In contrast to earlier work on network coding in DTNs, we observe and explain the gains due to network coding even under an inter-session setting. Our results from extensive simulations of appropriately chosen "minimal" topologies quantify the gains due to each enhancement feature. We show that substantial gains can be achieved by our proposed enhancements that are very simple to implement.

2004

In this paper, we study the delay and capacity trade-off in mobile ad hoc networks. We consider an ad hoc network with n nodes distributed uniformly on a sphere. The nodes are mobile, and move in accordance with the random way-point mobility model, used widely in the ad hoc networks literature. We show that the 2-hop relaying algorithm proposed by Grossglauser and Tse , incurs an expected packet delay of Θ(nT p (n)), where T p (n) is the packet duration. We show that any protocol that allows only nearest neighbor transmissions, incurs an expected packet delay of Ω(T p (n) √ n). We show that the trade-off: delay/capacity ≥ Θ(T p (n)n), is both necessary as well as sufficient in mobile ad hoc networks. A protocol which introduces redundancy into the 2-hop relaying algorithm, and offers a throughput of Θ(1/k(n)) and an expected packet delay of Θ(nT p (n)/k(n)), for any k(n) = O( √ n), is developed.

2010 Ieee Wireless Communication and Networking Conference, 2010

In this paper, a transmission strategy of fountain codes over cooperative relay networks is proposed. When more than one relay nodes are available, we apply network coding to fountain-coded packets. By doing this, partial information is made available to the destination node about the upcoming message block. It is therefore able to reduce the required number of transmissions over erasure channels, hence increasing the effective throughput. Its application to wireless channels with Rayleigh fading and AWGN noise is also analysed, whereby the role of analogue network coding and optimal weight selection is demonstrated.

Int'l J. of Communications, Network and System Sciences, 2014

Network Coding is a relatively new forwarding paradigm where intermediate nodes perform a store, code, and forward operation on incoming packets. Traditional forwarding approaches, which employed a store and forward operation, have not been able to approach the limit of the max-flow min-cut throughput wherein sources transmitting information over bottleneck links have to compete for access to these links. With Network Coding, multiple sources are now able to transmit packets over bottleneck links simultaneously, achieving the max-flow min-cut throughput and increasing network capacity. While the majority of the contemporary literature has focused on the performance of Network Coding from a capacity perspective, the aim of this research has taken a new direction focusing on two Quality of Service metrics, e.g., Packet Delivery Ratio (PDR) and Latency, in conjunction with Network Coding protocols in Mobile Ad Hoc Networks (MANETs). Simulations are performed on static and mobile environments to determine a Quality of Service baseline comparison between Network Coding protocols and traditional ad hoc routing protocols. The results show that the Random Linear Network Coding protocol has the lowest Latency and Dynamic Source Routing protocol has the highest PDR in the static scenarios, and show that the Random Linear Network Coding protocol has the best cumulative performance for both PDR and Latency in the mobile scenarios.

2005

In this paper, we study the delay and capacity trade-off in mobile ad hoc networks. We consider an ad hoc network with n nodes distributed uniformly on a sphere. The nodes are mobile, and move in accordance with the random way-point mobility model, used widely in the ad hoc networks literature. We show that the 2-hop relaying algorithm proposed by Grossglauser and Tse , incurs an expected packet delay of Θ(nT p (n)), where T p (n) is the packet duration. We show that any protocol that allows only nearest neighbor transmissions, incurs an expected packet delay of Ω(T p (n) √ n). We show that the trade-off: delay/capacity ≥ Θ(T p (n)n), is both necessary as well as sufficient in mobile ad hoc networks. A protocol which introduces redundancy into the 2-hop relaying algorithm, and offers a throughput of Θ(1/k(n)) and an expected packet delay of Θ(nT p (n)/k(n)), for any k(n) = O( √ n), is developed.