Efficient vehicle-to-Internet routing and address autoconfiguration are two of the missing pieces required to provide Internet connectivity from vehicles. Here, we propose TREBOL, a tree-based and configurable protocol which benefits from the inherent tree-shaped nature of vehicle to Internet traffic to reduce the signaling overhead while dealing efficiently with the vehicular dynamics.
Seguir leyendo arrow_right_altIn the talk I overview some recent results for optimization problems that originate in optical networks. They deal with optimizing the utilization of regenerators (switching components that regenerate a signal after a certain distance) and ADMs (Add-Drop Multiplexers).
Seguir leyendo arrow_right_altThis presentation intends to extract some useful hints on how to successfully manage an internationalisation process. It is focused on the specific case of a Spanish very large company: Telefónica, the leading Spanish telecommunications operator and one of the Top Ten telcos in the worldwide ranking by market cap nowadays.
Seguir leyendo arrow_right_altNowadays users expect to experience highly dependable network connectivity and services. However, several recent episodes demonstrate that software errors and operator mistakes continue to cause undesired disturbances and outages. Software-defined networking (SDN) is a new kind of network architecture that decouples the control plane from the data plane - a vision currently embodied in OpenFlow. By logically centralizing the control-plane computation, SDN provides the opportunity to remove complexity from and introduce new functionality in our networks. On the other hand, as the network programmability enhances, risks arise that buggy software in network controllers may disrupt an entire network.
Seguir leyendo arrow_right_altThe increasing demand for higher data rates in cellular network results in increasing network density. As a consequence, inter-cell interference is becoming the most serious obstacle towards spectral efficiency. Therefore, considering that radio resources are limited and expensive, new techniques are required for efficient radio resource allocation in next generation cellular networks. In this paper, we propose a pure frequency reuse 1 scheme based on base station scheduling rather than the commonly adopted user scheduling. In particular, we formulate a base station scheduling problem to determine which base stations can be scheduled to simultaneously transmit, without causing excessive interference to any user of any of the scheduled base stations. We show that finding the optimal base station scheduling is NP-hard, and formulate the BASICS (BAse Station Inter-Cell Scheduling) algorithm, a novel heuristic to approximate the optimal solution at low complexity cost. The proposed algorithm is in line with the ABSF (almost blank sub-frame) technique recently standardized at the 3GPP. By means of numerical and packet-level simulations, we prove the effectiveness and superiority of BASICS as compared to the state of the art of inter-cell interference mitigation schemes.
Seguir leyendo arrow_right_altThe placement of regenerators in optical networks has become an active area of research during the last years. Given a set of lightpaths in a network G and a positive integer d, regenerators must be placed in such a way that in any lightpath there are no more than d hops without meeting a regenerator. In the talk I present a few optimization problems that arise within this framework.
Seguir leyendo arrow_right_altAuctions have regained interest from researchers due to its different new applications (Google AdWords auctions, cloud computing auctions, privacy auctions, and white spaces spectrum auctions). In this work in particular we explore auctions for spectrum that can be allocated either to a single bidder (for licensed use) or to a collection of bidders (for unlicensed use).
Seguir leyendo arrow_right_altWhile a considerable amount of research has been devoted to peer-to-peer backup and storage, no such system actually became widely adopted in the wild. My take on this is that there is the opportunity to build better, and possibly more successful, systems: while some design issues (e.g., erasure coding and data indexing) have been well explored, others have been barely scratched.
Seguir leyendo arrow_right_altThe media access control (MAC) layer of the IEEE 802.11 standard specifies a set of parameters that regulate the behavior of the wireless stations when accessing the channel. Although the standard defines a set of recommended values for these parameters, they are statically set and do not take into account the current conditions in the wireless local area network (WLAN) in terms of, e.g., number of contending stations and the traffic they generate, which results in suboptimal performance.
Seguir leyendo arrow_right_altMobile devices are energy-limited. Both industry and the research community proposed solutions to overcome these limitations with relative success at different levels such as hardware, operating system and even applications.
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