Underwater acoustic networks

Charla invitada.Wireless underwater acoustic communication systems have become one of the most promising technologies for the development and deployment of future ocean observation and sensor networks. Applications range from oil prospecting and transportation to aquaculture, and include pollution control, climate recording, prediction of natural disturbances, search and survey missions, etc. The high attenuation of electromagnetic waves in underwater medium precludes them from being used as the information vehicle. Therefore, acoustic waves are the most viable alternative for the transmission. Nevertheless, the underwater acoustic channel is not free of drawbacks. On the contrary, it exhibits important obstacles that must be overcome if communication networks are to be implemented in the future. In addition, underwater systems have inherently serious problems of power supply and batteries duration. At the same time, network protocols must take into account the specific characteristics of the transmission medium, not dismissing the slow propagation speed. This talk will present an overall view of the acoustic channel characteristics and their impact on network protocols.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Recognizing complex gestures via natural interfaces

Natural interfaces have revolutionized the way we interact with computers. They have provided in many fields a comfortable and efficient mechanism that requires no computer knowledge, nor artificial controlling devices, but allow as to interoperate via natural gestures. Diverse fields such as entertainment, remote control, medicine, fitness exercise are finding improvements with the introduction of this technology. However, most of these sensorial interfaces only provide support for basic gestures. In this work we show how it is possible to construct your own complex gestures using the underlying capabilities of these sensor devices.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Self-organized Routing For Radial Underwater Networks

Due to significant propagation delay of acoustic waves in underwater communication, terrestrial routing protocols are not applicable for UWSN. To overcome this problem, some routing protocols have been proposed for UWSN based on the location of the nodes. The routing protocols proposed for UWSN usually require measuring additional parameters, which make the protocol inefficient in terms of energy conservation. Sometimes, also time synchronization among the nodes is required, which is also not an easy task in UWSN. We propose a route initialization mechanism, which avoids these constraints. A path will be formed between all nodes and the gateway, decreasing the forwarding delay and increasing the throughput.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Challenges In Video Quality Assessment For Underwater Wireless Sensor Networks

Underwater Networks poses as a challenging environment for video transmissions mainly because of an extremely limited available bitrate. In such constrained conditions, it is crucial to know the opinion of users which will settle the difference between an effective and a useless service. However, the hostilities of the underwater channel extend to Video Quality Assessment adding challenges specific to this service context. The present work explores the major issues in the standard approaches to quality assessment: subjective experiments where human users evaluate the service and objective mathematical models for opinion scores. The main problems are presented and some key directions for future research are identified.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Investigation of Underwater Acoustic Modems: Architecture, Test Environment & Performance

Underwater acoustic communication has emerged as one of the active research and development area. There are several design challenges which need to be carefully address including modem size, power consumption, interference, data rate and communication distance. In this paper the architecture, test environment and performance of underwater acoustic modems designed in the last five years have been investigated. The outcomes of the investigation would be highly valuable for researchers, designers, and developers of the domain.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Métodos y Herramientas para el Diseño y Verificación de Sistemas de Comunicaciones Móviles

El objetivo de esta Tesis ha sido la consecución de tecnología para el diseño y mantenimiento eficientes, en coste temporal y económico, de Sistemas de Pruebas para equipos de comunicaciones inalámbricas. El proceso de diseño elaborado se ha basado en un conjunto de principios básicos: uso de lenguajes y notaciones ITU, independencia de la plataforma de ejecución y uso de herramientas comerciales. En esta Tesis se describe: a) Una arquitectura genérica para Sistemas de Pruebas. b) Una Metodología de Diseño de Sistemas de Pruebas. c) Un conjunto de herramientas de soporte. d) Una propuesta de metodología para el modelado con SDL. e) La aplicación a Sistemas de Pruebas de capa física de la arquitectura, métodos y herramientas utilizados en el área de protocolos. f) Un conjunto de implementaciones que validan las aportaciones anteriores

Calidad de transmisión de vídeo en redes de comunicaciones submarinas

La adquisición de imágenes submarinas plantea en la actualidad importantes dificultades especialmente en términos de coste y/o retardo en la disponibilidad de la información. Las transmisiones de vídeo a través de redes submarinas permitirían reducir de manera notable ambos problemas, sin embargo, la tecnología existente para el despliegue de este tipo de redes está basada en módems acústicos que poseen capacidades de transmisión muy limitadas debidas a las adversas características de propagación del entorno submarino. El estudio de la calidad alcanzable en esas condiciones es un aspecto clave en el análisis de estos servicios de vídeo pues permite evaluar su viabilidad y establecer una relación entre las aplicaciones y los recursos de red necesarios para su ejecución.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Subjective quality in underwater acoustic networks

Experiencias sobre calidad subjetiva percibida en redes acústicas submarinasUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Analysis of M2M Capabilities in 4G

M2M (Machine to Machine) communications enable many new applications that reduce the costs of maintenance and operation via remote monitoring and control. The forecasts for this type of communications predict traffic increases associated with these devices of about 100% in the coming years. However, the behaviour of M2M devices is different from the human user, which causes stress on the networks due to the overload of the signalling procedures. This paper reviews the literature on the current scenario, projections for the decade, and improvements that LTE (Long Term Evolution) will offer for this segment of devices.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Optimal Fair Scheduling in S-TDMA Sensor Networks for Monitoring River Plumes

Underwater wireless sensor networks (UWSNs) are a promising technology to provide oceanographers with environmental data in real time. Suitable network topologies to monitor estuaries are formed by strings coming together to a sink node.This network may be understood as an oriented graph. A number of MAC techniques can be used in UWSNs, but Spatial-TDMA is preferred for fixed networks. In this paper, a scheduling procedure to obtain the optimal fair frame is presented, under ideal conditions of synchronization and transmission errors. The main objective is to find the theoretical maximum throughput by overlapping the transmissions of the nodes while keeping a balanced received data rate from each sensor, regardless of its location in the network. The procedure searches for all cliques of the compatibility matrix of the network graph and solves a Multiple-Vector Bin Packing (MVBP) problem. This work addresses the optimization problem and provides analytical and numerical results for both the minimum frame length and the maximum achievable throughput