Sparse Intra-Flow Network Coding: comportamiento y modelado

Los autores agradecen la financiación del Gobierno de España (Ministerio de Economía y Competitividad, Fondo Europeo de Desarrollo Regional, FEDER) de este trabajo a través del proyecto ADVICE, Dynamic provisioning of connectivity in high density 5G wireless scenarios (TEC2015-71329-C2-1-R)

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)

Uplink power control modeling for dense OFDMA-based heterogeneous networks

In this paper we propose a novel model for the uplink in heterogeneous cellular networks. Opposed to previous works, we accurately account for the mutual interference caused by other users’ connections, and we pose an optimization problem that can be straightforwardly solved to establish the minimum required transmission power that satisfies the minimum Signal-to-Interferenceplus-Noise Ratio (SINR) constraint. We assess the validity of the proposed approach by comparing the observed results with those obtained with a traditional closed-loop power control scheme. The main benefit of our solution is that it does not require any iteration to find the transmission power, while legacy approaches usually need a number of steps before finding it. Finally, we study the behavior of the uplink for different access selection strategies, and we compare the SINR and transmission power of open-loop and closed-loop power control solutions.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 ADVICE: Dynamic provisioning of connectivity in high density 5G wireless scenarios (TEC2015-71329-C2-1-R) and Future Internet Enabled Resilient Cities (FIERCE)

Accurate simulation of 802.11 indoor links: a “bursty” channel model based on real measurements

We propose a novel channelmodel to be used for simulating indoor wireless propagation environments. An extensive measurement campaign was carried out to assess the performance of different transport protocols over 802.11 links. This enabled us to better adjust our approach, which is based on an autoregressive filter. One of the main advantages of this proposal lies in its ability to reflect the “bursty” behavior which characterizes indoor wireless scenarios, having a great impact on the behavior of upper layer protocols.We compare this channel model, integrated within the Network Simulator (ns-2) platform, with other traditional approaches, showing that it is able to better reflect the real behavior which was empirically assessed

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

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)

An alternative procedure to obtain the mortality rate with non-linear functions: application to the case of the Spanish population

This paper presents an alternative calculation procedure to calculate the mortality rate, exploiting the data available in the Eurostat demography database for Spain. This methodology has been devised based on two of the most widely known and widespread models to establish the mortality rate: The Gompertz-Makeham (GM) and Lee-Carter (LC) models. Our main goal is to obtain a model yielding a similar accuracy than LC or GM, but able to capture the variation of their parameters over time and ages. The method proposed herewith works by applying simple or double fitting, with non-linear functions, to the values of the parameters considered by each one of such models. One of the main advantages of our approach is that we considerably reduce the amount of data that is required to establish the mortality rate, with respect to what would be needed if the traditional models were used. On the other hand, it also allows analyzing the evolution of the mortality rate, even if no real data was available for a particular year. The results evince that, besides fulfilling the two aforementioned goals, the proposed scheme yields an estimation error that is comparable with that offered by the traditional approach.This work has been supported in part by the Spanish Government (MINECO) and Fondo Europeo de Desarrollo Regional (FEDER) by means of the ADVICE (TEC2015-71329) project. Ramon Aguero was also partially supported by the Future Internet Enabled Resilient Cities (FIERCE) project, RTI2018-093475-A-100 (MCIU/AEI/FEDER/UE)

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)

A geometric programming solution for the mutual-interference model in HetNets

It is well known that the use of heterogeneous networks and densification strategies will be crucial to handle the wireless cellular traffic increase that is foreseen in the forthcoming years. Hence, the scientific community is putting effort into the proposal and assessment of radio resource management solutions for this type of deployments. For that, an accurate modeling of the underlying resources is mandatory. In this letter, we propose a mutual-interference model, which enables a precise estimation of the signal-to-interference and noise ratio (SINR), compared with the widespread constant-load alternative. This is of utter relevance, since the SINR has a direct influence on the spectral efficiency and, consequently, on the resources to be allocated. We also propose a transformation of the corresponding resource assignment problem, so that it can be solved using geometric programming techniques. The validity of this transformation is assessed by comparing the corresponding solution with the one that would have been obtained exploiting a heuristic approach (simulated annealing).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, Dynamic provisioning of connectivity in high density 5G wireless scenarios (TEC2015-71329-C2-1-R

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)