Towards an Optimized Traffic-Aware Routing in Wireless Mesh Networks

International audienceIn this paper we study through simulations the impact of PHY/MAC protocols on higher layers. In a comparative way, we investigate the effectiveness of some protocols when they coexist on a wireless mesh network environment. Results show that PHY/MAC parameters have an important impact on routing performances. Based on these results, we propose two tra c-aware routing metrics based on link availability. The information about the link availability/occupancy is picked up from lower layers using a cross-layer approach. The rst metric is load-sensitive and aims to balance the tra c load according to the availability of a link to support additional ows. The second metric reproduces better the capacity of a link since it is based on its residual bandwidth. Using several real experiments, we have shown that our proposals can accurately determine better paths in terms of throughput and delay. Our experiments are carried out into an heterogeneous IEEE 802.11n based network running with OLSR routing protocol

Cross Layer Design to Reduce the Latency for Effective Scheduling Technique for Mobile Ad hoc Networks

Wireless Mesh Networking (WMN) technology provides a key revolutionary to the future backbone network access. WMN adopt a multihop based transmission to improve end to end data delivery. The 802.11s MAC (Medium Access Control) is designed using CSMA (Carrier Sense Medium Access) protocol which result in collision of slot due to failure in detecting hidden node in WMN. Various methodologies have been developed to optimize the MAC and hidden node and exposed node detection algorithm in recent time to utilize slot efficiently and reduce latency. Slot reutilization is an effective way in reducing latency but due to improper detection of hidden node of existing algorithm the latency is increased. To overcome this, our work propose an efficient device classification based MAC scheduler by adopting a cross layer design to reduce the latency. The experiment are conducted by varying network size and density and the outcome shows that the proposed approach perform better than existing CSMA/OCA in term of latency

A taxonomy and evaluation for developing 802.11‐based wireless mesh network testbeds

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92433/1/dac1299.pd

Efficiency of WLAN 802.11xx in the multi-hop topology

The article presents the research results of the performance of wireless multi-hop networks. The analysis of the decrease in performance of such networks depending on the number of hops was performed for three popular transmission techniques used in mesh networks: Hybrid Wireless Mesh Protocol (default routing protocol for 802.11s), Optimized Link State Routing Protocol and Wireless Distribution System. Based on the measurements results, mathematical models for the decreasing of network transmission parameters depending on the number of hops were developed

Cross-Layer-Optimierungen für WLAN-Mesh-Netzwerke

Gegenstand dieser Arbeit ist es, das Verhalten von IEEE-802.11s-Mesh-Netzwerken in der Praxis zu untersuchen und Strategien und Lösungen zu entwickeln, durch die einerseits die Administrierbarkeit und Skalierbarkeit komplexer Mesh-Backbones erhöht werden und andererseits verteilte Anwendungen die darunter liegende Netzwerkstruktur gezielt berücksichtigen können, um das vorhandene Datendurchsatzpotential effizient zu nutzen.The aim of this thesis is to investigate the practical behavior of IEEE 802.11s mesh networks and to develop strategies and solutions that, on the one hand, increase the scalability and manageability of complex mesh backbones and, on the other hand, enable distributed applications to explicitly consider the underlying network structure, allowing them to utilize the available network capacity efficiently

Customized Wireless Mesh Routing Metric for Swarm of Drones Applications

With the proliferation of drones applications, there is an increasing need for handling their numerous challenges. One of such challenges arises when a swarm-of-drones is deployed to accomplish a specific task which requires coordination and communication. While this swarm-of-drones is essentially a special form of mobile ad hoc networks (MANETs) which has been studied for many years, there are still some unique requirements of drone applications that necessitates re-visiting MANET approaches. These challenges stem from 3-D environments the drones are deployed in, and their specific way of mobility which adds to the wireless link management challenges. In this thesis, we consider the existing 802.11s wireless mesh standard and adopt its routing capabilities for swarm-of-drones. Specifically, we propose two link quality routing metrics called SrFTime and CRP metrics as an improvement to the 802.11s default Airtime routing metric, to enable better network throughput for drone applications. SrFTime improve network performance of stationary and mobile Wireless Mesh Networks, while CRP is designed to fit the link characteristics of drones and enable more efficient routes from these to their gateway. The evaluations in the actual 802.11s standard indicate that our proposed metrics outperforms the existing one consistently under various conditions

Mesh networks for handheld mobile devices

Mesh communications emerge today as a very popular networking solution. Mesh networks have a decentralized and multihop design. These characteristics arouse interest in research for relevant novel features, such as cooperation among nodes, distribution of tasks, scalability, communication with limited infrastructure support, and the support of mobile devices as mesh nodes. In addition to the inexistence of a solution that implements mesh networks with mobile devices at the data link layer (Layer 2), there is also a need to reconsider existing metrics with new information to tackle the intrinsic characteristics of mobile devices, e.g., the limited energy resources of their battery. To tackle this problem, this thesis presents a detailed study about projects, routing protocols and metrics developed in the area of mesh networks. In addition, two data link layer solutions, Open802.11s and B.A.T.M.A.N-advanced, have been adapted and deployed in a real mesh network testbed with off the shelf routers devices installed with a customized operating system. From this testbed, Open802.11s has proved to offer better performance than B.A.T.M.A.N-advanced. Following this, a breakthrough in this work has been the integration of the 802.11s on an Android mobile device and its subsequent incorporation in the mesh network. This allowed the study of eventual limitations imposed by the mobile device on the operation of the mesh network, namely performance and energy scarcity. With this, another major novelty has followed, by designing, implementing and evaluating several energy related metrics regarding the battery status of mobile devices. This has enabled the participation of mobile devices in mesh routing paths in an efficient way. Our main objective was to implement a mesh network with mobile devices. This has been achieved and validated through the evaluation of diverse testing scenarios performed in a real mesh testbed. The obtained results also show that the operation of a mesh with mobile devices can be enhanced, including the lifetime of mobile devices, when an energy-aware metric is used.As redes mesh surgem hoje em dia como uma solução de rede em crescimento e expansão. Neste tipo de redes o comportamento entre os nós é descentralizado e numa topologia de multihop. Estas características despertam interesse na pesquisa e desenvolvimento de novas funcionalidades tais como: cooperação entre nós, distribuição de tarefas, escalabilidade da rede e comunicações mesmo em casos de uma infraestrutura limitada e o suporte de dispositivos móveis como nós de uma rede mesh. Associado à inexistência de um projecto que implemente redes mesh em dispositivos móveis na camada de ligação de dados (Layer 2), surge a necessidade de repensar as métricas já existentes com novas informações que façam face às novas características dos dispositivos móveis, neste caso, os recursos limitados de bateria. Por forma a resolver este problema, este trabalho apresenta um estudo detalhado sobre os projetos, protocolos de routing e métricas desenvolvidas na área das redes mesh. Além disso, duas soluções que utilizam a camada de ligação de dados, Open802.11s e BATMAN-advanced, estes foram adaptadao e implementados num testbed real utilizando routers com um sistema operacional costumizado instalado. Deste testbed, concluiu-se que o Open802.11s obtem um melhor desempenho que o BATMAN-advanced. Assim, um dos avanços deste trabalho foi a integração do Open802.11s num dispositivo móvel Android e sua posterior incorporação na rede mesh. Isto permitiu o estudo de eventuais limitações impostas pelo dispositivo móvel ao funcionar numa rede mesh, ou seja, desempenho e a escassez de energia. Com isso, foi concebida outra novidade, através da concepção, avaliação e implementação de várias métricas relacionadas com a energia e que têm por base o estado da bateria do dispositivo. Isto permitiu que os dispositivos móveis participem na rede mesh e a sua gestão de bateria seja feita de forma eficiente. O principal objectivo era a implementação de uma rede mesh com dispositivos móveis. Este foi alcançado e validado através de diversos cenários de teste reais. Os resultados obtidos demonstram também que o funcionamento de uma rede mesh com dispositivos móveis pode ser melhorada, incluindo o tempo de vida dos dispositivos móveis, quando uma métrica que considera a energia é utilizada

Link Availability Aware Routing Metric For Wireless Mesh Networks

International audienceThis paper investigates the design of effective routing metrics in the purpose of network resources optimization and the satisfaction of users QoS requirements. Using several real experiments, we point out the shortcoming of the Expected Transmission Count (ETX) metric for eventual optimizations towards a more efficient routing. Experiments were carried out into an heterogeneous IEEE 802.11n based network running with OLSR routing protocol and have shown that ETX presents several shortcoming resulting in inaccurate estimation of the link quality and then of the routing decision. This paper presents improvements of the ETX metric based on link availibility for accurately finding high-throughput paths in multihop wireless mesh networks