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    Modeling the energy performance of LoRaWAN Casals Ibáñez, Lluís; Mir Masnou, Bernat; Vidal Ferré, Rafael; Gómez Montenegro, Carlos LoRaWAN is a flagship Low-Power Wide Area Network (LPWAN) technology that has highly attracted much attention from the community in recent years. Many LoRaWAN end-devices, such as sensors or actuators, are expected not to be powered by the electricity grid; therefore, it is crucial to investigate the energy consumption of LoRaWAN. However, published works have only focused on this topic to a limited extent. In this paper, we present analytical models that allow the characterization of LoRaWAN end-device current consumption, lifetime and energy cost of data delivery. The models, which have been derived based on measurements on a currently prevalent LoRaWAN hardware platform, allow us to quantify the impact of relevant physical and Medium Access Control (MAC) layer LoRaWAN parameters and mechanisms, as well as Bit Error Rate (BER) and collisions, on energy performance. Among others, evaluation results show that an appropriately configured LoRaWAN end-device platform powered by a battery of 2400 mAh can achieve a 1-year lifetime while sending one message every 5 min, and an asymptotic theoretical lifetime of 6 years for infrequent communication.

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    5G transport network requirements for the next generation fronthaul interface Bartelt, Jens; Vucic, Nikola; Camps Mur, Daniel; García Villegas, Eduard; Seyfettin Demirkol, Ilker; Fehske, Albrecht; Grieger, Michael; Tzanakaki, Anna; Gutiérrez Terán, Jesús; Grass, Eckhard; Lyberopoulos, George; Fettweis, Gerhard To meet the requirements of 5G mobile networks, several radio access technologies, such as millimeter wave communications and massive MIMO, are being proposed. In addition, cloud radio access network (C-RAN) architectures are considered instrumental to fully exploit the capabilities of future 5G RANs. However, RAN centralization imposes stringent requirements on the transport network, which today are addressed with purpose-specific and expensive fronthaul links. As the demands on future access networks rise, so will the challenges in the fronthaul and backhaul segments. It is hence of fundamental importance to consider the design of transport networks alongside the definition of future access technologies to avoid the transport becoming a bottleneck. Therefore, we analyze in this work the impact that future RAN technologies will have on the transport network and on the design of the next generation fronthaul interface. To understand the especially important impact of varying user traffic, we utilize measurements from a real-world 4G network and, taking target 5G performance figures into account, extrapolate its statistics to a 5G scenario. With this, we derive both per-cell and aggregated data rate requirements for 5G transport networks. In addition, we show that the effect of statistical multiplexing is an important factor to reduce transport network capacity requirements and costs. Based on our investigations, we provide guidelines for the development of the 5G transport network architecture.

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    Joint optimization of path selection and link scheduling for millimeter wave transport networks Huerfano, Diego; Seyfettin Demirkol, Ilker; Legg, Peter In future mobile networks, the wireless transport networks are expected to carry traffic flows with different throughput and delay requirements due to the introduction of Cloud-RAN (C-RAN) and different functional splits that can be used, e.g., as defined by Next Generation Fronthaul Interface (NGFI). A promising wireless technology to support the high throughput requirements of C-RAN splits is Millimeter Wave (mmWave) band technologies standardized by IEEE 802.11ad amendment. Our target here is to derive the mathematical formulation of the path selection and link scheduling problem for mmWave transport networks, where the backhaul and fronthaul flows will co-exist, by defining the constraints brought by different functional splits and the IEEE 802.11ad standard. We present two objective functions that can be used for this problem: load balancing and minimization of the use of air time. We implemented the derived formulations in an Mixed-Integer Linear Programming (MILP) solver and evaluated realistic scenarios of wireless fronthaul/backhaul networks assessing the splits defined by NGFI for LTE.

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    5G transport network blueprint and dimensioning for a dense urban scenario Seyfettin Demirkol, Ilker; Camps Mur, Daniel; Bartelt, Jens; Zou, Jim In this paper, we provide a quantitative evaluation of the deployment aspects and dimensioning of the 5G transport architecture in a representative European city. In particular, we select an example dense urban city scenario based on the city of Barcelona, and illustrate how the transport network architecture defined by the 5G-XHaul project can be deployed in that environment. Building on the case of Barcelona, we discuss physical deployment aspects, such as the locations to deploy small cells, how many compute facilities should be scattered throughout the city, or where the control plane functions should be deployed. In addition, we provide a quantitative evaluation of the 5G-XHaul deployment in Barcelona, including the bandwidth required at the different segments of the architecture, i.e. the wireless segment, the WDM-PON access network, and the TSON metro network. We also evaluate control plane aspects, such as the number of 5G-XHaul SDN controllers required for a city like Barcelona.

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    Bluetooth low energy mesh networks: a survey Gómez Montenegro, Carlos; Darroudi, Seyed Mahdi luetooth Low Energy (BLE) has gained significant momentum. However, the original design of BLE focused on star topology networking, which limits network coverage range and precludes end-to-end path diversity. In contrast, other competing technologies overcome such constraints by supporting the mesh network topology. For these reasons, academia, industry, and standards development organizations have been designing solutions to enable BLE mesh networks. Nevertheless, the literature lacks a consolidated view on this emerging area. This paper comprehensively surveys state of the art BLE mesh networking. We first provide a taxonomy of BLE mesh network solutions. We then review the solutions, describing the variety of approaches that leverage existing BLE functionality to enable BLE mesh networks. We identify crucial aspects of BLE mesh network solutions and discuss their advantages and drawbacks. Finally, we highlight currently open issues

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    A distributed man-machine dispatching architecture for emergency operations based on 3GPP mission critical services Viamonte Solé, David; Calveras Augé, Anna M. With the number of non-human devices expected to significantly overtake human users of LTE networks, it is no surprise that First Responders in Mission Critical operations will need to interact with an increasing number of unmanned devices, “bots” or drones. In the paper we propose the Mission Critical “bot” concept as an entity capable of gathering environmental/situational information and triggering certain automated actions without the need of human intervention. We prove that in certain circumstances these bots can help quickly resolve emergency situations and complement traditional centralized coordination from Dispatch Control Rooms. We explain how such “bots” relate and expand the 3GPP Mission Critical Communications architecture framework, considering different architectural approaches and complexity levels. Importantly, because First Responders must remain focused, hands-free and context-aware most of the time, we cover specifically the case where man-machine interaction is based on voice communication without having to use hands or look at a screen. It is hence of particular interest to convert “bot” interactions into audio information exchanged over push-to-talk communication services, be it through the cellular network or leveraging the 3GPP device-to-device capability. The paper is complemented with theoretical use cases as well as description and multimedia material of a prototype implementation of a concept emulator.

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    Wireless-optical network convergence: enabling the 5G architecture to support operational and end-user services Tzanakaki, Anna; Anastasopoulos, Markos; Berberana, Ignacio; Syrivelis, Dimitris; Flegkas, Paris; Korakis, Thanasis; Camps Mur, Daniel; Seyfettin Demirkol, Ilker; Gutiérrez Terán, Jesús; Grass, Eckhard; Wei, Qing; Pateromichelakis, Emmanouil; Vucic, Nikola; Fehske, Albrecht; Grieger, Michael; Eiselt, Michael; Bartelt, Jens; Fettweis, Gerhard; Lyberopoulos, George; Theodoropoulou, Eleni; Simeonidou, Dimitra This article presents a converged 5G network infrastructure and an overarching architecture to jointly support operational network and end-user services, proposed by the EU 5G PPP project 5G-XHaul. The 5G-XHaul infrastructure adopts a common fronthaul/backhaul network solution, deploying a wealth of wireless technologies and a hybrid active/passive optical transport, supporting flexible fronthaul split options. This infrastructure is evaluated through a novel modeling. Numerical results indicate significant energy savings at the expense of increased end-user service delay. © 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

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    SENSEFUL: An SDN-based joint access and backhaul coordination for Dense Wi-Fi Small Cells García Villegas, Eduard; Sesto Castilla, David; Zehl, Sven; Zubow, Anatolij; Betzler, August; Camps Mur, Daniel Dense Small Cell networks are considered the most effective way to cope with the exponential increase in mobile traffic demand expected for the upcoming years and are one of the foundations of the future 5G. However, novel architectures are required to enable cost-efficient deployments of very dense outdoor Small Cell networks, complementing the coverage layer provided by macro-cells. In this regard, two important challenges need to be solved to make this vision a reality: i) increased traffic dynamics, which are translated into more frequent handovers, and ii) cost-efficient deployment of large number of Small Cells. In this paper we propose and evaluate SENSEFUL, an novel architecture addressing the two problems highlighted above: Software-Defined Networking (SDN) as the key technology to promote adaptability to a varying environment and provide efficient mobility solutions in the dense access layer, and novel wireless backhauling technologies where traditional wired connectivity does not meet cost/efficiency restrictions. © 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

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    A bluetooth low energy indoor positioning system with channel diversity, weighted trilateration and Kalman filtering Cantón Paterna, Vicente; Calveras Augé, Anna M.; Paradells Aspas, Josep; Perez Bullones, Maria Antonia Indoor Positioning Systems (IPS) using Bluetooth Low Energy (BLE) technology are currently becoming real and available, which has made them grow in popularity and use. However, there are still plenty of challenges related to this technology, especially in terms of Received Signal Strength Indicator (RSSI) fluctuations due to the behaviour of the channels and the multipath effect, that lead to poor precision. In order to mitigate these effects, in this paper we propose and implement a real Indoor Positioning System based on Bluetooth Low Energy, that improves accuracy while reducing power consumption and costs. The three main proposals are: frequency diversity, Kalman filtering and a trilateration method what we have denominated “weighted trilateration”. The analysis of the results proves that all the proposals improve the precision of the system, which goes up to 1.82 m 90% of the time for a device moving in a middle-size room and 0.7 m for static devices. Furthermore, we have proved that the system is scalable and efficient in terms of cost and power consumption. The implemented approach allows using a very simple device (like a SensorTag) on the items to locate. The system enables a very low density of anchor points or references and with a precision better than existing solutions

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    Joint access-backhaul perspective on mobility management in 5G networks Rony, Rakibul Islam; Jain, Akshay; López Aguilera, M. Elena; García Villegas, Eduard; Seyfettin Demirkol, Ilker The ongoing efforts in the research, development and standardization of 5G, by both industry and academia, have resulted in the identification of enablers (Software Defined Networks, Network Function Virtualization, Distributed Mobility Management, etc.) and critical areas (Mobility management, Interference management, Joint access-backhaul mechanisms, etc.) that will help achieve the 5G objectives. During these efforts, it has also been identified that the 5G networks, due to their high degree of heterogeneity, high QoS demand and the inevitable density (both in terms of access points and users), will need to have efficient joint backhaul and access mechanisms as well as enhanced mobility management mechanisms in order to be effective, efficient and ubiquitous. Therefore, in this paper, we first provide a discussion on the evolution of the backhaul scenario, and the necessity for joint access and backhaul optimization. Subsequently, and since mobility management mechanisms can entail the availability, reliability and heterogeneity of the future backhaul/fronthaul networks as parameters in determining the most optimal solution for a given context, a study with regards to the effect of future backhaul/fronthaul scenarios on the design and implementation of mobility management solutions in 5G networks has been performed. © 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

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    Internet of Satellites (IoSat): an interconnected space paradigm Ruiz de Azúa Ortega, Joan Adrià; Calveras Augé, Anna M.; Camps Carmona, Adriano José During the last years the space has been populated by Distributed Satellite Systems, which some of them have started to implement Inter-Satellite Communication. However, current solutions are composed of a unique mission and homogeneous spacecrafts or a combination of them. This actually limits their use in the so-called “Federated Satellite Systems” that proposes the interconnection of heterogeneous spacecrafts in order to establish a mission collaboration whenever the resources are not used for the primary mission goal. This point-to-point proposal has some limitations that can be addressed in a multi-hop platform, i.e. a network. Current satellite network proposals, such as Space Internet or Heterogeneous Spacecraft Network, propose the creation of a common network backbone which provides connectivity for future missions. However, this approach supposes huge maintenance and deployment costs. This work presents a new interconnected space paradigm based on a more peer-to-peer architecture: Internet of Satellites. This new paradigm promotes the creation of sporadic networks, called Inter Satellite Networks, which provide the required communication means to deploy Federated Satellite Systems for multi-hop cases.

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    IEEE 802.11ax: challenges and requirements for future high efficiency wifi Afaqui, Muhammad Shahwaiz Iqbal; García Villegas, Eduard; López Aguilera, M. Elena The popularity of IEEE 802.11 based wireless local area networks (WLANs) has increased significantly in recent years because of their ability to provide increased mobility, flexibility, and ease of use, with reduced cost of installation and maintenance. This has resulted in massive WLAN deployment in geographically limited environments that encompass multiple overlapping basic service sets (OBSSs). In this article, we introduce IEEE 802.11ax, a new standard being developed by the IEEE 802.11 Working Group, which will enable efficient usage of spectrum along with an enhanced user experience. We expose advanced technological enhancements proposed to improve the efficiency within high density WLAN networks and explore the key challenges to the upcoming amendment.

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    From 6LoWPAN to 6Lo: expanding the universe of IPv6-supported technologies for the Internet of Things Gómez Montenegro, Carlos; Paradells Aspas, Josep; Bormann, Carsten; Crowcroft, Jon Leveraging 6LoWPAN, the IETF 6Lo Working Group has targeted adaptation of IPv6 over a new generation of communication technologies for the IoT. These comprise Bluetooth LE, ITU-T G.9959, DECT ULE, MS/TP, NFC, IEEE 1901.2, and IEEE 802.11ah. This article comprehensively analyzes the 6Lo technologies and adaptation layers, giving the motivation for critical design decisions, highlighting crucial aspects for performance, and presenting main challenges. © 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works

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    Evaluation of IEEE 802.11 coexistence in WLAN deployments López Aguilera, M. Elena; García Villegas, Eduard; Casademont Serra, Jordi Wi-Fi has become a successful technology since the publication of its first WLAN standard due to continuous advances and updates while remaining always backwards compatible. Backwards compatibility among subsequent standards is an important feature in order to take advantage of previous equipment when publishing a new amendment. At present, IEEE 802.11b support is still mandatory to obtain the Wi-Fi certification. However, there are several harmful effects of allowing old legacy IEEE 802.11b transmissions in modern WLAN deployments. Lower throughput per device is obtained at slow rates, but also the effect known as performance anomaly, which nearly leads to starvation of fast stations, has to be taken into account. Finally, backwards compatibility mechanisms pose an important penalty in throughput performance for newer specifications. This paper presents a thorough analysis of the current state of IEEE 802.11, comparing coverage range and throughput performance among subsequent amendments, and focusing on the drawbacks and benefits of including protection mechanisms. This is a pre-print of an article published in Wireless Networks. The final authenticated version is available online at: https://doi.org/10.1007/s11276-017-1540-z.

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    TCP in the Internet of Things: from ostracism to prominence Gómez Montenegro, Carlos; Arcia Moret, Andrés; Crowcroft, Jon TCP has traditionally been neglected as a transport-layer protocol for the Internet of Things (IoT). However, recent trends and industry needs are favoring TCP presence in IoT environments. In this article, we describe the main IoT scenarios where TCP will be used. We then analyze the historically claimed issues of TCP in the IoT context. We argue that, in contrast to generally accepted wisdom, most of those possible issues fall in one of the following categories: i) are also found in well-accepted IoT end-to-end reliability mechanisms, ii) can be solved, or iii) are not actual issues. Considering the future prominent role of TCP in the IoT, we provide recommendations for lightweight TCP implementation and suitable operation in such scenarios, based on our IETF standardization work on the topic. © 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

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    Publish/subscribe protocol in wireless sensor networks: improved reliability and timeliness García Davis, Ernesto; Calveras Augé, Anna M. The rapidly-evolving demand of applications using wireless sensor networks in several areas such as building and industrial automation or smart cities, among other, makes it necessary to determine and provide QoS support mechanisms which can satisfy the requirements of applications. In this paper we propose a mechanism that establishes different QoS levels, based on Publish/Subscribe model for wireless networks to meet application requirements, to provide reliable delivery of packet and timeliness. The first level delivers packets in a best effort way. The second one intends to provide reliable packet delivery with a novel approach for Retransmission Timeout (RTO) calculation, which adjusts the RTO depending on the subscriber Packet Delivery Ratio (PDR). The third one provides the same reliable packet delivery as the second one, but in addition, it provides data aggregation trying to be efficient in terms of energy consumption and the use of network bandwidth. The last one provides timeliness in the packet delivery. We evaluate each QoS Level with several performance metrics such as PDR, Message Delivery Ratio, Duplicated and Retransmitted Packet Ratio and Packet Timeliness Ratio to demonstrate that our proposal provides significant improvements based on the increase of the PDR obtained.

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    A novel wake-up communication system using solar panel and visible light communication Carrascal, Carolina; Seyfettin Demirkol, Ilker; Paradells Aspas, Josep One of the most promising energy-efficient communication methods is the use of wake-up receivers. In this paper, we propose and develop a novel wake-up communication system that uses Visible Light Communication (VLC) and an indoor solar panel as the receiver of the wake-up signal. After the reception of the wake-up signal, an interrupt generated by the wake-up receiver wakes up the wireless device attached. Through experiments we show the feasibility of the system and characterize its performances in terms of wake-up probabilities for different distances. We present two configuration options: an addressable and a broadcast-based wake-up configuration. We evaluate the effect of light interferences and show that the achieved wake-up distances under these conditions are reasonable for indoor scenarios.

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    A two-way radio communication across a multi-hop wireless sensor network based on a commercial IEEE 802.15.4 compliant platform Herrera, Laura; Calveras Augé, Anna M.; Catalán Cid, María Luisa Wireless Sensor Networks, and especially IEEE 802.15.4, are originally defined for low cost applications, with low bit rates and power restrictions in mind. However, the ubiquity of the nodes and their easy connectivity also enable them to be used in supporting real time services, for instance, emergency scenarios, where TETRA is usually the employed audio technology. Focusing on voice transmission, we present a performance evaluation of audio streaming over a multi-hop Low-Rate Wireless Personal Area Network in order to provide bidirectional audio communication using a commercial IEEE 802.15.4 compliant platform. This paper includes an assessment of different software protocols and compression algorithms to support audio transmission on a CC2530 System-on-Chip WSN mote. The results establish the maximum number of hops of a bidirectional single-route network under real- time voice quality constraints.

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    Internet of Satellites (IoSat): analysis of network models and routing protocol requirements Ruiz de Azúa Ortega, Joan Adrià; Calveras Augé, Anna M.; Camps Carmona, Adriano José The space segment has been evolved from monolithic to distributed satellite systems. One of these distributed systems is called the federated satellite system (FSS) which aims at establishing a win-win collaboration between satellites to improve their mission performance by using the unused on-board resources. The FSS concept requires sporadic and direct communications between satellites, using inter satellite links. However, this point-to-point communication is temporal and thus it can break existent federations. Therefore, the conception of a multi-hop scenario needs to be addressed. This is the goal of the Internet of satellites (IoSat) paradigm which, as opposed to a common backbone, proposes the creation of a network using a peer-to-peer architecture. In particular, the same satellites take part of the network by establishing intermediate collaborations to deploy a FSS. This paradigm supposes a major challenge in terms of network definition and routing protocol. Therefore, this paper not only details the IoSat paradigm, but it also analyses the different satellite network models. Furthermore, it evaluates the routing protocol candidates that could be used to implement the IoSat paradigm.

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    Smart Inclusive University - Posibilidades de las TIC hacia una universidad para todos Vidal Ferré, Rafael; Guasch Murillo, Daniel; Casals Ibáñez, Lluís; García Villegas, Eduard; Gómez Montenegro, Carlos; López Aguilera, M. Elena; Martín Escalona, Israel; Bestraten Castells, Sandra Cinta; Àlvarez Suau, Maria Hortènsia; Nogués Freixas, Cristina

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