Flow Allocation for Maximum Throughput and Bounded Delay on Multiple Disjoint Paths for Random Access Wireless Multihop Networks

In this paper, we consider random access, wireless, multi-hop networks, with multi-packet reception capabilities, where multiple flows are forwarded to the gateways through node disjoint paths. We explore the issue of allocating flow on multiple paths, exhibiting both intra- and inter-path interference, in order to maximize average aggregate flow throughput (AAT) and also provide bounded packet delay. A distributed flow allocation scheme is proposed where allocation of flow on paths is formulated as an optimization problem. Through an illustrative topology it is shown that the corresponding problem is non-convex. Furthermore, a simple, but accurate model is employed for the average aggregate throughput achieved by all flows, that captures both intra- and inter-path interference through the SINR model. The proposed scheme is evaluated through Ns2 simulations of several random wireless scenarios. Simulation results reveal that, the model employed, accurately captures the AAT observed in the simulated scenarios, even when the assumption of saturated queues is removed. Simulation results also show that the proposed scheme achieves significantly higher AAT, for the vast majority of the wireless scenarios explored, than the following flow allocation schemes: one that assigns flows on paths on a round-robin fashion, one that optimally utilizes the best path only, and another one that assigns the maximum possible flow on each path. Finally, a variant of the proposed scheme is explored, where interference for each link is approximated by considering its dominant interfering nodes only.Comment: IEEE Transactions on Vehicular Technolog

Software defined wireless backhauling for 5G networks

Some of the important elements to guarantee a network?s minimum level of performance are: i) using an efficient routing of the data traffic and, ii) a good resource allocation strategy. This project proposes tools to optimise these elements in an IEEE 802.11ac-based wireless backhaul network considering the constraints derived from an implementation in a software defined network. These tools have been designed using convex optimisation?s theory in order to provide an optimal solution that ensures a circuit mode routing where the impact in higher and lower layers of the network is considered. Additionally, the traffic dynamics of the network is controlled by a sensitivity analysis of the convex problem using the Lagrange multipliers to adapt the solution to the changes produced by the evolution of the traffic. Finally, results obtained using the proposed solutions show an improved performance in bit rate and end-to-end delay with respect to typical routing algorithms for simple and complex network deployments.Algunos elementos importantes para asegurar unos niveles mínimos de rendimiento en una red son: i) utilizar un enrutamiento eficiente del tráfico de datos y, ii) una buena estrategia en la asignación de recursos. Este proyecto propone herramientas para optimizar estos elementos en una red de backhaul inalámbrica basada en el protocolo IEEE 802.11ac considerando las restricciones derivadas de una implementación en una software defined network (red definida por software). Estas herramientas han sido diseñadas utilizando la teoría de optimización convexa para proponer una solución óptima que asegure un enrutamiento en modo circuito en el que se considere el impacto en capas altas y bajas de la red. Además, la dinámica del tráfico de la red se controla mediante un análisis se sensibilidad del problema convexo utilizando los multiplicadores de Lagrange para adaptar la solución a cambios de la red producidos por la evolución del tráfico. Finalmente, los resultados obtenidos a partir de las soluciones propuestas demuestran un mejor rendimiento en bit rate y latencia extremo a extremo respecto a algoritmos de enrutamiento típicos tanto en despliegues de redes sencillas como más complejas.Alguns elements importants per assegurar uns nivells mínims de rendiment en una xarxa són: i) utilitzar un encaminament eficient del trànsit de dades i, ii) una bona estratègia en l'assignació de recursos. Aquest projecte proposa eines per optimitzar aquests elements en una xarxa de backhaul sense fils basada en el protocol IEEE 802.11ac considerant les restriccions derivades d'una implementació en una software defined network (xarxa definida per software). Aquestes eines han estat dissenyades utilitzant la teoria d'optimització convexa per tal de proposar una solució òptima que asseguri un encaminament en mode circuit on es consideri l'impacte en capes altes i baixes de la xarxa. A més, la dinàmica del trànsit de la xarxa es controla mitjançant una anàlisi de sensibilitat del problema convex utilitzant els multiplicadors de Lagrange per adaptar la solució a canvis de la xarxa produïts per l'evolució del trànsit. Finalment, els resultats obtinguts a partir de les solucions proposades demostren un millor rendiment en bit rate i latència extrem a extrem respecte a algoritmes d'encaminament típics tant en desplegaments de xarxes senzilles com més complexes