Control de topología en redes inalámbricas de tipo malla con estructura de comunidades

Abstract

Wireless mesh networks (WMNs) are networks whose main objective is to provide ubiquitous and wireless connectivity to their clients through a set of mesh routers (MR). The WMNs architecture can be classified into 3 groups depending on the functionalities of the nodes: infrastructure, client WMNs, and hybrid wireless mesh networks as a combination of the above. The client WMNs are networks whose management should be as spontaneous as possible. Nowadays, spontaneous networks are emerging as a possible new paradigm of communication, characterized by a strong self-organization and self-maintenance nature. The most common cases are networks formed mainly by mobile devices carried by people. In such spontaneous networks, the devices fulfill both the role of the end user interface, as well as being the traffic router of their peers. Spontaneous networks are usually conformed by portable devices. When these devices are associated with people moving from one place to another, they acquire the human mobility attribute. Most of these networks with such mobility patterns present an organized community structure. Due to technological advance, mobile phones increasingly generate an area of interest for researchers, in order to take advantage of real-time information, to benefit personal and environment care. The combination of such smart devices with social relationships is a reason to incorporate social characteristics into network design strategies. Due to the large number of devices that can exist in these spontaneous networks, there are problems such as: overhead, high probability of packet collision, interference, energy inefficiency, etc. Therefore, arises the need to implement topology control mechanisms that take into account the nodes’s social interaction. Under this context, this project proposes and evaluates three topology control schemes based on centrality metrics in combination with community detection algorithms, for communitystructured WMNs. Each of the evaluated schemes uses a different method for routers selection which will form the network backbone. When evaluating the methods, it is concluded that the Community-Aware Highest Betweenness Centrality Neighbor (C-A HCBN) method achieves the best network connectivity with a reduced number of selected routers for all the mobility models under study. An analysis of the evolution of the reduced topologies is carried out. In all cases, there is an average of less than 50% of nodes that are chosen to fulfill the functions of routers, and the number of times that a node changes its state on average goes from 22 to 41 seconds depending on the mobility model. C-A HCBN is also compared to a previous topology control mechanism which doesn’t consider community structure. The simulation results with real-time traffic (UDP) conclude that our method is better in terms of network performance and energy efficiency. Finally, we propose an additional topology control mechanism based on the minimum spanning tree algorithm. This method manages to obtain smaller topologies than C-A HCBN However, network performance with traffic load is affected by the reduced number of MR in this method. The evaluation of the proposal is carried out by means of extensive simulations using the ns-3 software, a free licensed discrete event network simulator based on C ++, highly diffused and used by the scientific community. The mobility traces are obtained by BonnMotion and SUMO, which are tools for generation and mobility scenario analysis. Generation and visualization of network graphs are obtained with Gephi. Other software that are used for data processing are Octave and Python.