Hybrid RSS-RTT Localization Scheme for Indoor Wireless Networks

[EN]Nowadays, a variety of information related to the distance between two wireless devices can be easily obtained. This paper presents a hybrid localization scheme that combines received signal strength (RSS) and round-trip time (RTT) information with the aim of improving the previous localization schemes. The hybrid localization scheme is based on an RSS ranging technique that uses RTT ranging estimates as constraints among other heuristic constraints. Once distances have been well estimated, the position of the mobile station (MS) to be located is estimated using a new robust least-squared multilateration (RLSM) technique that combines the RSS and RTT ranging estimates mitigating the negative effect of outliers. The hybrid localization scheme coupled with simulations and measurements demonstrates that it outperforms the conventional RSS-based and RTT-based localization schemes, without using either a tracking technique or a previous calibration stage of the environment.Dirección General de Telecomunicaciones de la Consejería de Fomento de Castilla y Leó

International Conference on Broadband Communications, Networks and Systems

Producción CientíficaNetwork Function Virtualization (NFV) is considered to be one of the enabling technologies for 5G. NFV poses several challenges, like deciding the virtual network function (VNF) placement and chaining, and adding backup resources to guarantee the survivability of service chains. In this paper, we propose a genetic algorithm that jointly solves the VNF-placement, chaining and virtual topology design problem in WDM metro ring network, with the additional capacity of providing node protection. The simulation results show how important is to solve all of these subproblems jointly, as well as the benefits of using shared VNF and network resources between backup instances in order to reduce both the service blocking ratio and the number of active CPUs.Ministerio de Economía, Industria y Competitividad (grant TEC2017-84423-C3-1-P)Ministerio de Industria, Comercio y Turismo (grant BES 2015-074514)INTERREG V-A España-Portugal (POCTEP) (grant 0677_DISRUPTIVE_2_E)

A testbed and a simulation laboratory for training engineering students in optical access network technologies

Producción CientíficaEngineering profiles focused on next-generation optical networks are gaining immense importance due to new emerging services and the amount of data expected in future network scenarios. In fact, not only are optical access networks leading to a major revolution in the network industry, but passive optical networks are the most widely deployed access networks worldwide today. This should be a strong incentive for universities to train their students in these innovative and recent technologies. In this vein, we propose the deployment of an optical communication laboratory with on-site experimental sessions in which students work with commercial equipment and realistic working environments. These working environments are necessary to train professionals in the area of optical networks. However, due to the high cost of the optical communications equipment, it is not possible to have a working place for each group and we combine these experimental sessions with some simulation sessions to complete the training. We present the design of this lab and a qualitative and quantitative study aimed at analyzing students’ experiences, the skills they have acquired, and the potential impact on their future careers. This study shows that students have a very positive perception of the lab, emphasizing that working with real equipment helps them improve technical skills and assimilate theoretical knowledge. They also point out they would like a higher number of subjects in their degrees to employ this type of lab. Finally, students perceive these sessions as very useful for their professional future.Unión Europea a través del programa INTERREG V-A España-Portugal (project 0677_DISRUPTIVE_2_E)Junta de Castilla y León (grant VA085G19)Ministerio de Ciencia, Innovación y Universidades (grants TEC2017-84423-C3-1-P and RED2018-102585-T

2020 22nd International Conference on Transparent Optical Networks (ICTON)

Producción CientíficaNetwork Function Virtualization (NFV) is a promising networking paradigm that will ease the network manageability and increase its flexibility, while reducing costs. In this paradigm, operators must solve the Virtual Network Function (VNF) placement and chaining problems. It is also important to provide backup resources to ensure the survivability of the offered services when a node failure happens. In this paper, we compare two different protection approaches to ensure the service resilience: individual VNF protection and end-to-end protection. Results show the benefits in terms of use of computing resources and energy consumption of protecting each VNF individually, compared to the end-to-end protection approach.Ministerio de Economía, Industria y Competitividad (grant TEC2017-84423-C3-1-P)Ministerio de Industria, Comercio y Turismo (fellowship BES-2015-074514)Research network Go2Edge (grant RED2018-102585-T)Interreg V-A Spain-Portugal (POCTEP) programme 2014- 202

Experimental assessment of a cognitive mechanism to reduce the impact of outdated TEDs in optical networks

Producción CientíficaWe have recently proposed and demonstrated, by means of simulation, the benefits of a simple yet effective cognitive technique to enhance stateless Path Computation Element algorithms with the aim of reducing the connection blocking probability when relying on a potentially non-up-to-date traffic engineering database. In this paper, we employ that technique, called elapsed time matrix (ETM), in the framework of the CHRON (Cognitive Heterogeneous Reconfigurable Optical Network) architecture and, more importantly, validate and analyze its performance in an emulation environment (rather than in a simulation environment) supporting impairment-aware lightpath establishment. Not only dynamic lightpath establishment on demand has been studied, but also restoration processes when facing optical link failures. Emulation results demonstrate that ETM reduces the blocking probability when establishing lightpaths on demand, and increases the percentage of successful restorations in case of optical link failure. Moreover, the use of that technique has little impact on lightpath setup time and lightpath restoration time, respectively.Ministerio de Ciencia e Innovación (Projects TEC2010-21178-C02-02 and TEC2014-53071-C3-2-P)European Community’s Seventh Framework Programme [FP7/2007-2013] CHRON project (Cognitive Heterogeneous Reconfigurable Optical Network) under grant agreement no 25864

PID controller based on a self-adaptive neural network to ensure qos bandwidth requirements in passive optical networks

Producción CientíficaIn this paper, a proportional-integral-derivative (PID) controller integrated with a neural network (NN) is proposed to ensure quality of service (QoS) bandwidth requirements in passive optical networks (PONs). To the best of our knowledge, this is the first time an approach that implements a NN to tune a PID to deal with QoS in PONs is used. In contrast to other tuning techniques such as Ziegler-Nichols or genetic algorithms (GA), our proposal allows a real-time adjustment of the tuning parameters according to the network conditions. Thus, the new algorithm provides an online control of the tuning process unlike the ZN and GA techniques, whose tuning parameters are calculated offline. The algorithm, called neural network service level PID (NNSPID), guarantees minimum bandwidth levels to users depending on their service level agreement, and it is compared with a tuning technique based on genetic algorithms (GASPID). The simulation study demonstrates that NN-SPID continuously adapts the tuning parameters, achieving lower fluctuations than GA-SPID in the allocation process. As a consequence, it provides a more stable response than GA-SPID since it needs to launch the GA to obtain new tuning values. Furthermore, NN-SPID guarantees the minimum bandwidth levels faster than GA-SPID. Finally, NN-SPID is more robust than GA-SPID under real-time changes of the guaranteed bandwidth levels, as GA-SPID shows high fluctuations in the allocated bandwidth, especially just after any change is made.Ministerio de Ciencia e Innovación (Projects TEC2014-53071-C3-2-P and TEC2015-71932-REDT

An Experimental SDN Proposal over Legacy GPONs to Allow Real-Time Service and Residential Network Reconfiguration

Producción CientíficaIn this paper we propose an experimental SDN (Software Defined Networking) solution over legacy GPON (Gigabit Passive Optical Network) equipment that allow a control of the network configuration and its services. On the one hand, the proposal permits to move certain global bandwidth and service configuration policies outside the GPON so that they can be managed centrally by an SDN controller. In legacy PONs the real-time bandwidth allocation process is made inside the network infrastructure cycle by cycle between the OLT (Optical Line Terminal) and the ONTs (Optical Network Terminals) so the network performance could be adversely affected due to the latency between the SDN controller and the PON. In contrast, the control of some global DBA strategies by SDN techniques could lead to better network and management configuration and therefore our proposal is able to dynamically adjust these policies according to the real-time Quality of Service (QoS) requirements of residential users. On the other hand, the designed SDN proposal permits network subscribers to control the performance of their residential homes. In this way, they can set constraints and dynamically customize the bandwidth of their connected devices in a very transparent and efficient way.Junta de Castilla y León (Project VA085G19)Ministerio de Economía, Industria y Competitividad (Project TEC2017-84423-C3-1-P)INTERREG V-A España-Portugal (POCTEP) program (0677_DISRUPTIVE_2_E

2021 International Conference on Optical Network Design and Modeling (ONDM)

Producción CientíficaThe planning of multi-access edge computing (MEC) systems does not only consist in distributing MEC servers among the base stations (BSs) but also in designing the network to interconnect BSs, MEC resources and the wide area network (WAN) gateway. Due to their high bandwidth, fiber links are the best option for those connections in 5G environments. In contrast to previous works, which only solve the server placement problem, in this paper, an integer linear programming (ILP) formulation is proposed for solving both problems while reducing the installation cost (servers and fibers). The fiber deployment cost is especially important in sparsely populated areas as the distance between BSs are much longer than in urban environments. The model was tested using real BSs locations and population data showing that the formulation considerably reduces the installation cost.Interreg V-A Spain-Portugal (POCTEP) programme 2014- 2020 (project 0667_DISRUPTIVE_2_E)Ministerio de Economía, Industria y Competitividad (projects TEC2017-84423-C3-1-P and RED2018- 102585-T)Junta de Castilla y León - Fondo Europeo de Desarrollo Regional (project VA231P20

FITCE 2017

Producción CientíficaThe following topics are dealt with: protocols; telecommunication computing; cloud computing; mean square error methods; 5G mobile communication; optical fibre subscriber loops; optical fibre networks; passive optical networks; optical time-domain reflectometry; computer aided instruction.Ministerio de Ciencia e Innovación (Projects TEC2014-53071-C3-2-P and TEC2015-71932-REDT

2022 IEEE International Mediterranean Conference on Communications and Networking (MeditCom)

Producción CientíficaIn Multi-access Edge Computing (MEC) network planning, the main goal is to find the optimal network topology, including the location and dimensioning of MEC data centers (MEC-DC), and the connections between them, with base stations (BSs), and with the wide area network (WAN) gateway for Internet and cloud services. Moreover, the assignment of traffic to the servers must also be solved. When solving that problem, it is especially important to consider the connections if the deployment has to be done in sparsely populated areas with long distances to interconnect and where it is likely to find no adequate infrastructure previously deployed. In a previous paper, we presented an Integer Linear Programming (ILP) formulation that solves that problem assuming straight and dedicated cable ducts between network nodes. However, reusing cables ducts and exploiting space division multiplexing (using different fibers of each cable to reach different nodes) can lead to more cost-effective solutions. Moreover, it is crucial to implement redundancy between MEC-DCs and WAN gateways to provide survivability against failures in this network segment. In this paper, we present a heuristic to improve the result obtained with our previous ILP formulation, assuming shared fiber ducts and cables, and creating a ring topology between MEC-DCs and WAN gateways. Results show that our proposal reduces the total deployment cost, while fulfilling latency constraints of MEC applications and providing fault tolerance.FEDER a través del Programa INTERREG V-A España-Portugal 2014-2020 (0677_DISRUPTIVE_2_E)Consejería de Educación de la Junta de Castilla y León y FEDER (VA231P20)Ministerio de Ciencia e Innovación y Agencia Estatal de Investigación (Proyecto PID2020-112675RB-C42 financiado por MCIN/AEI/10.13039/501100011033 y RED2018-102585-T