Improving wireless multicast communications with NC: performance assessment over a COTS platform

Multicast services are believed to play a relevant role in next wireless networking scenarios. In this paper we exploit Tunable Sparse Network Coding techniques to increase reliability of multicast communications. We show that the proposed network coding scheme yields a better performance than state-of-the-art solutions, which are traditionally based on retransmissions. We first use a model to analytically compare the two approaches. Then, we validate and broaden this analysis by means of an experimental campaign over a testbed deployed with Commercial Of-The-Shelf devices. This platform, comprising low cost devices (Raspberry-PI), allows us to assess the feasibility of the proposed solution, which offers a relevant gain in terms of performance.This work has been supported by the Spanish Government (Ministerio de Economía y Competitividad, Fondo Europeo de Desarrollo Regional, FEDER) by means of the project ADVICE (TEC2015-71329-C2-1-R)

Joint scheduling and coding for low in-order delivery delay over lossy paths with delayed feedback

We consider the transmission of packets across a lossy end-to-end network path so as to achieve low in-order delivery delay. This can be formulated as a decision problem, namely deciding whether the next packet to send should be an information packet or a coded packet. Importantly, this decision is made based on delayed feedback from the receiver. While an exact solution to this decision problem is challenging, we exploit ideas from queueing theory to derive scheduling policies based on prediction of a receiver queue length that, while suboptimal, can be efficiently implemented and offer substantially better performance than state of the art approaches. We obtain a number of useful analytic bounds that help characterise design trade-offs and our analysis highlights that the use of prediction plays a key role in achieving good performance in the presence of significant feedback delay. Our approach readily generalises to networks of paths and we illustrate this by application to multipath trans port scheduler design.This work has been supported by the Spanish Government (Ministerio de Economía y Competitividad, Fondo Europeo de Desarrollo Regional, FEDER) by means of the project ADVICE (TEC2015-71329-C2-1-R)

A Markov chain model for the decoding probability of sparse network coding

Random linear network coding has been shown to offer an efficient communication scheme, leveraging a remarkable robustness against packet losses. However, it suffers from a high-computational complexity, and some novel approaches, which follow the same idea, have been recently proposed. One of such solutions is sparse network coding (SNC), where only few packets are combined with each transmission. The amount of data packets to be combined can be set from a density parameter/distribution, which could be eventually adapted. In this paper, we present a semi-analytical model that captures the performance of SNC on an accurate way. We exploit an absorbing Markov process, where the states are defined by the number of useful packets received by the decoder, i.e., the decoding matrix rank, and the number of non-zero columns at such matrix. The model is validated by the means of a thorough simulation campaign, and the difference between model and simulation is negligible. We also include in the comparison of some more general bounds that have been recently used, showing that their accuracy is rather poor. The proposed model would enable a more precise assessment of the behavior of SNC techniques.This work has been supported by the Spanish Government (Ministerio de Economía y Competitividad, Fondo Europeo de Desarrollo Regional, FEDER) by means of the projects COSAIF, “Connectivity as a Service: Access for the Internet of the Future” (TEC2012-38754-C02-01), and ADVICE (TEC2015-71329-C2-1-R). This work was also financed in part by the TuneSCode project (No. DFF 1335-00125) granted by the Danish Council for Independent Research

Systematic network coding with overlap for IoT scenarios

The presence of IoT in current networking scenarios is more relevant every day. IoT covers a wide range of applications, ranging from wearable devices to vehicular communications. With the consolidation of Industry 4.0, IIoT (Industrial IoT) environments are becoming more common. Communications in these scenarios are mostly wireless, and due to the lossy nature of wireless communications, the loss of information becomes an intrinsic problem. However, loss recovery schemes increase the delay that characterizes any communication. On the other hand, both reliability (robustness) and low delay are crucial requirements for some applications in IIoT. An interesting strategy to improve both of them is the use of Network Coding techniques, which have shown promising results, in terms of increasing reliability and performance. This work focuses on a possible new coding approach, based on systematic network coding scheme with overlapping generations. We perform a thorough analysis of its behavior. Based on the results, we draw out a number of conclusions for practical implementations in wireless networks, focusing our interest in IIoT environments.The authors are grateful for the funding of the Industrial Doctorates Program from the University of Cantabria (Call 2018). This work has been partially supported by the Basque Government through the Elkartek program under the DIGITAL project (Grant agreement no. KK-2019/00095), as well as by the Spanish Government (MINECO, MCIU, AEI, FEDER) by means of the projects ADVICE: Dynamic provisioning of connectivity in high density 5G wireless scenarios (TEC2015-71329-C2-1-R) and FIERCE: Future Internet Enabled Resilient Cities (RTI2018-093475-A-100)

Caracterización experimental del comportamiento de Network Coding para comunicaciones multicast

Las comunicaciones multicast, caracaterizadas por la existencia de una única fuente, que transmite la misma información a múltiples destinos, están llamadas a ser un ingrediente relevante en las redes de siguiente generación. Este trabajo se centra en el uso del esquema de codificación de red Random Linear Network Coding (RLNC) para ofrecer una mayor escalabilidad en ese tipo de comunicaciones, frente a otros esquemas más tradicionales, incrementando la fiabilidad extremo a extremo. Los resultados teóricos ponen de manifiesto la gran ventaja que supone el utilizar técnicas de codificación, frente al uso de retransmisiones selectivas para recuperar la información perdida. Además, se muestra la viabilidad de la solución propuesta, desplegándola sobre una plataforma experimental compuesta por múltiples dispositivos de bajo coste, Raspberry-Pi’s.Los autores querían expresar su agradecimiento al Gobierno de España por su financiación en el proyecto “Aprovisionamiento Dinámico de Conectividad en Escenarios inalámbricos 5G de alta Densidad ADVICE (TEC2015-71329-C2-1-R)

Performance of random linear coding over multiple error-prone wireless links

In this letter we derive an exact formulation for the performance of Random Linear Coding (RLC) when applied over multiple wireless links. We combine this technique with UDP so as to offer a reliable communication service . We extend a previous result, which only considered one single link, to embrace both multiple sources as well as varying quality of wireless links. We establish the number of excess packets that are required to successfully accomplish the communication and, based on the Bianchi model, we calculate the achieved throughput. We also propose a context-aware probabilistic transmission scheme that leads to a relevant performance gain. We use a thorough simulation-based study over the ns-3 framework to assess the validity of the proposed model and to broaden the corresponding analysis.This work has been supported by the Spanish Government by its funding through the project COSAIF, “Connectivity as a Service: Access for the Internet of the Future” (TEC2012-38754-C02-01)

Exploiting sparse coding: A sliding window enhancement of a random linear network coding scheme

Random Linear Network Coding (RLNC) is a technique that provides several benefits. For instance, when applied over wireless mesh networks, it can be exploited to ease routing solutions as well as to increase the robustness against packet losses. Nevertheless, the complexity of the decoding process and the required overhead might jeopardize its performance. There is a trade-off when deciding the field and block sizes; larger values decrease the probability of transmitting linearly dependent packets, but they also increase both the required overhead and the decoding complexity. In order to overcome these limitations, we propose a sliding window enhancement; a fixed number of packets (fewer than the block size) is combined within every transmission, and the decoding process can therefore take advantage of the algebra with sparse matrices. The paper presents an analytical model, which is first validated and later broaden by means of an extensive simulation campaign carried out over the ns-3 simulator.This work has been supported by the Spanish Government by its funding through the project COSAIF, “Connectivity as a Service: Access for the Internet of the Future” (TEC2012-38754-C02-01)

Performance and complexity of tunable sparse network coding with gradual growing tuning functions over wireless networks

Random Linear Network Coding (RLNC) has been shown to be a technique with several benefits, in particular when applied over wireless mesh networks, since it provides robustness against packet losses. On the other hand, Tunable Sparse Network Coding (TSNC) is a promising concept, which leverages a trade-off between computational complexity and goodput. An optimal density tuning function has not been found yet, due to the lack of a closed-form expression that links density, performance and computational cost. In addition, it would be difficult to implement, due to the feedback delay. In this work we propose two novel tuning functions with a lower computational cost, which do not highly increase the overhead in terms of the transmission of linear dependent packets compared with RLNC and previous proposals. Furthermore, we also broaden previous studies of TSNC techniques, by means of an extensive simulation campaign carried out using the ns-3 simulator. This brings the possibility of assessing their performance over more realistic scenarios, e.g considering MAC effects and delays. We exploit this implementation to analyze the impact of the feedback sent by the decoder. The results, compared to RLNC, show a reduction of 3.5 times in the number of operations without jeopardizing the network performance, in terms of goodput, even when we consider the delay effect on the feedback sent by the decoderThis work has been supported by the Spanish Government (Ministerio de Economía y Competitividad, Fondo Europeo de Desarrollo Regional, FEDER) by means of the projects COSAIF, “Connectivity as a Service: Access for the Internet of the Future” (TEC2012-38754-C02-01), and ADVICE (TEC2015-71329-C2-1-R). This work was also financed in part by the TuneSCode project (No. DFF 1335-00125) granted by the Danish Council for Independent Research

rQUIC: Integrating FEC with QUIC for robust wireless communications

QUIC, fostered by Google and under standardization in the IETF, integrates some of HTTP/s, TLS, and TCP functionalities over UDP. One of its main goals is to facilitate transport protocol design, with fast evolution and innovation. However, congestion control in QUIC is still severely jeopardized by packet losses, despite implemented loss recovery mechanisms, whose behavior strongly depends on the Round Trip Time. In this paper, we design and implement rQUIC, a framework that enables FEC within QUIC protocol to improve its performance over wireless networks. The main idea behind rQUIC is to reduce QUIC's loss recovery time by making it robust to erasures over wireless networks, as compared to traditional transport protocol loss detection and recovery mechanisms. We evaluate the performance of our solution by means of extensive simulations over different type of wireless networks and for different applications. For LTE and Wifi networks, our results illustrate significant gains of up to 60% and 25% savings in the completion time for bulk transfer and web browsing, respectively.Özgü Alay was partially supported the Norwegian Research Council project No. 250679 (MEMBRANE). Ramón Agüero was partially supported by the Spanish Government (MINECO, MCIU, AEI, FEDER) by means of the projects ADVICE: Dynamic provisioning of connectivity in high density 5G wireless scenarios (TEC2015-71329-C2-1-R) and FIERCE: Future Internet Enabled Resilient Cities (RTI2018-093475-A-100)

Providing reliable services over wireless networks using a low overhead random linear coding scheme

In this work, we propose a novel intra-flow network coding solution, which is based on the combination of a low overhead Random Linear Coding (RLC) scheme and UDP, to offer a reliable communication service. In the initial protocol specification, the required overhead could be rather large and this had an impact over the observed performance. We therefore include an improvement to reduce such overhead, by decreasing the header length. We describe an analytical model that can be used to assess the performance of the proposed scheme. We also use an implementation within the ns-3 framework to assess the correctness of this model and to broaden the analysis, considering different performance indicators and more complex network topologies. In all cases, the proposed solution clearly outperforms a more traditional approach, in which the TCP protocol is used as a means to offer a reliable communication service.This work has been supported by the Spanish Government by its funding through the project COSAIF, “Connectivity as a Service: Access for the Internet of the Future” (TEC2012-38754-C02-01)