Smart handoff technique for internet of vehicles communication using dynamic edge-backup node

© 2020 The Authors. Published by MDPI. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3390/electronics9030524A vehicular adhoc network (VANET) recently emerged in the the Internet of Vehicles (IoV); it involves the computational processing of moving vehicles. Nowadays, IoV has turned into an interesting field of research as vehicles can be equipped with processors, sensors, and communication devices. IoV gives rise to handoff, which involves changing the connection points during the online communication session. This presents a major challenge for which many standardized solutions are recommended. Although there are various proposed techniques and methods to support seamless handover procedure in IoV, there are still some open research issues, such as unavoidable packet loss rate and latency. On the other hand, the emerged concept of edge mobile computing has gained crucial attention by researchers that could help in reducing computational complexities and decreasing communication delay. Hence, this paper specifically studies the handoff challenges in cluster based handoff using new concept of dynamic edge-backup node. The outcomes are evaluated and contrasted with the network mobility method, our proposed technique, and other cluster-based technologies. The results show that coherence in communication during the handoff method can be upgraded, enhanced, and improved utilizing the proposed technique.Published onlin

Efficient medium access control protocol for vehicular ad-hoc networks

Intelligent transportation systems (ITS) have enjoyed a tremendous growth in the last decade and the advancement in communication technologies has played a big role behind the success of ITS. Inter-vehicle communication (IVC) is a critical requirement for ITS and due to the nature of communication, vehicular ad-hoc network technology (VANET) is the most suitable communication technology for inter-vehicle communications. In Practice, however, VANET poses some extreme challenges including dropping out of connections as the moving vehicle moves out of the coverage range, joining of new nodes moving at high speeds, dynamic change in topology and connectivity, time variability of signal strength, throughput and time delay. One of the most challenging issues facing vehicular networks lies in the design of efficient resource management schemes, due to the mobile nature of nodes, delay constraints for safety applications and interference. The main application of VANET in ITS lies in the exchange of safety messages between nodes. Moreover, as the wireless access in vehicular environment (WAVE) moves closer to reality, management of these networks is of increasing concern for ITS designers and other stakeholder groups. As such, management of resources plays a significant role in VANET and ITS. For resource management in VANET, a medium access control protocol is used, which makes sure that limited resources are distributed efficiently. In this thesis, an efficient Multichannel Cognitive MAC (MCM) is developed, which assesses the quality of channel prior to transmission. MCM employs dynamic channel allocation and negotiation algorithms to achieve a significant improvement in channel utilisation, system reliability, and delay constraints while simultaneously addressing Quality of Service. Moreover, modified access priority parameters and safety message acknowledgments will be used to improve the reliability of safety messages. The proposed protocols are implemented using network simulation tools. Extensive experiments demonstrated a faster and more efficient reception of safety messages compared to existing VANET technologies. Finally, improvements in delay and packet delivery ratios are presented

Spectrum handoff strategy for cognitive radio-based Mac in industrial wirless sensor and actuator networks

In this thesis, a Cognitive Radio(CR)-based MAC for Industrial Wireless Sensor and Actuator Network (IWSAN) applications is proposed. IWSANs are typically used for closed-loop control applications, and they demand strict requirements in terms of time and robustness. Low latency and low error rates are required in order not to endanger persons or machinery. Moreover, these applications operate in industrial environments such as factories or transport scenarios (as aeronautics or railway) where multipath fading and shadowing are present due to metal surfaces. Furthermore, interference from other communication systems or industrial machinery is also common in these environments. The proposed MAC, based on the CR paradigm, is capable of ensuring time and robustness requirements in industrial channels. In the process of designing the CR-based MAC for IWSAN applications, a comparison between several non-CR-based MACs and CR-based MACs has been carried out. This comparison, which allows stating the benefits of CR for these applications, is presented in this thesis. The performance of every MAC is determined theoretically using Network Calculus, and it is validated through OPNET simulations. CR solutions, due to their adaptability characteristics, are capable of avoiding interference and ensuring robustness in industrial environments. However, none of the selected MACs are capable of ensuring robustness without comprising time requirements, since interference is avoided but not in a bounded time. On the other hand, the MAC proposed in this thesis is capable of avoiding interference ensuring time and robustness requirements at the same time. This MAC is therefore suitable for IWSAN applications. To ensure a deterministic behavior against interference, a novel handoff algorithm, which detects interference and hops to another channel, has been proposed. This algorithm has been designed to be used jointly with one of the evaluated MACs. The detection of the interference and the hop to another channel is done in a bounded time, because the proposed algorithm detects interference while the system is transmitting. The performance of this proposal is evaluated using Network Calculus and OPNET simulations, and the results are compared with the system without the proposed handoff algorithm. The comparison of the results shows how the evaluated MAC is only capable of ensuring both time and robustness requirements when the proposed handoff strategy is used. Moreover, the spectrum sensing algorithm used to obtain information about the environment is delved and its performance is measured through MATLAB simulations. An energy detector has been chosen due to its simplicity. Also, a cyclostationary Modulation Classifier is presented and a simplification has been carried out allowing its implementation on real hardware. The Modulation Classifier is capable of distinguishing between OFDM, QPSK and GFSK signals. The performance of the algorithm is presented in this thesis for different signals and for different receiver impairments such as frequency offset, DC offset and I/Q imbalance. Finally, a cognitive platform to validate the spectrum sensing algorithms is presented. This platform has been designed using a Xilinx Virtex 6 FPGA by a working group composed of researchers from IK4-Ikerlan and Mondragon Unibertsitatea. The platform, which uses both spectrum sensing algorithms, is an Ethernet-to-RF bridge. It has been designed to replace an Ethernet wired link by a wireless one for IWSAN applications. The proposed platform ensures a reliable communication link against interference. In the proposed implementation, the energy detector is used by the transmitter in order to find a free channel to transmit data, whereas the modulation classifier is used by the receiver in order to distinguish between the signal transmitted by the RF-Ethernet bridge and other signals. In this way the receiver can find the channel where the transmitter is carrying out the communication.En esta tesis se propone una MAC basada en el paradigma de la Radio Cognitiva (RC) para redes de sensores y actuadores inalámbricos industriales. Estas redes se suelen utilizar para aplicaciones de control en lazo cerrado, que exigen requisitos estrictos de tiempo y robustez. Para no poner en peligro la salud de las personas o la maquinaria es necesario que la red asegure una baja latencia y una tasa baja de errores. Además, al trabajar en ambientes industriales como fábricas o transportes (trenes, aviones, etc.), estas redes tienen que hacer frente a canales con mucho desvanecimiento por multitrayecto y efecto sombra debido a las superficies metálicas. También es común en estos entornos que haya interferencias de otros sistemas de comunicaciones o de la propia maquinaria industrial. La MAC propuesta en esta tesis es capaz de asegurar los requisitos temporales y de robustez demandados trabajando en este tipo de entornos. En el proceso de diseño de la MAC basada en RC para redes de sensores y actuadores inalámbricos industriales, se ha llevado a cabo una comparación de diferentes MACs diseñadas para estas redes. Se han evaluado tanto MACs basadas en RC como no basadas en ella, estableciendo las ventajas de la RC para estas aplicaciones. La evaluación se ha llevado a cabo haciendo un estudio teórico mediante Network Calculus, cuyos resultados se han validado mediante simulaciones en OPNET. Los resultados muestran como la RC es capaz de evitar interferencias y asegurar robustez en ambientes industriales. Sin embargo, ninguna de las MACs seleccionadas ha conseguido asegurar ambos requisitos, temporales y de robustez, al mismo tiempo; se puede evitar las interferencias pero no sin comprometer los requisitos temporales de la aplicación. Sin embargo, la MAC propuesta es capaz de evitar interferencias asegurando al mismo tiempo los requisitos temporales y de robustez. Por lo tanto, la MAC propuesta es apropiada para este tipo de redes. Para asegurar el comportamiento determinista del sistema, se ha propuesto un novedoso algoritmo de handoff que es capaz de detectar una interferencia y saltar a otro canal. Este algoritmo se ha diseñado para ser utilizado conjuntamente con una de las MACs previamente evaluadas. La detección de la interferencia y el salto a otro canal se hace en un tiempo determinado de tiempo, ya que es posible detectar interferencias mientras el sistema está transmitiendo. Su rendimiento se ha evaluado mediante Network Calculus y simulaciones en OPNET, y se ha comparado con los resultados obtenidos con la MAC cuando no se utiliza el esquema propuesto. De la comparación se deduce que el esquema de handoff añade a la MAC la capacidad de asegurar a la vez los requisitos temporales y de robustez. Además, en la tesis se explica el algoritmo de spectrum sensing que la MAC utiliza para obtener información del entorno, y su rendimiento se ha estudiado mediante simulaciones en MATLAB. Debido a su simplicidad, se ha optado por un detector de energía para este propósito. También se presenta un clasificador de modulaciones cicloestacionario. Este clasificador ha sido simplificado todo lo posible para posibilitar su implementación en hardware real. El clasificador de modulaciones es capaz de distinguir entre señales OFDM, QPSK y GFSK. Su rendimiento se detalla para diferentes señales y para diferentes deficiencias presentes en el receptor, como son offset de frecuencia, offset de continua o desequilibrios I/Q. Por último, se presenta una plataforma cognitiva que se ha utilizado para validar los algoritmos de spectrum sensing. Un grupo de trabajo compuesto por investigadores de IK4-Ikerlan y Mondragon Unibertsitatea ha diseñado esta plataforma sobre una FPGA Virtex 6 de Xilinx. La plataforma, que utiliza los dos algoritmos de spectrum sensing, es un puente Ethernet-RF. Su objetivo es reemplazar un enlace cableado de Ethernet por uno inalámbrico para aplicaciones de redes de sensores y actuadores industriales. Gracias a los algoritmos de spectrum sensing, la plataforma es capaz de asegurar un enlace robusto ante interferencias. El detector de energía se utiliza en el transmisor para encontrar los posibles canales libres donde transmitir la información. Mientras que el clasificador de modulaciones se utiliza en el receptor para distinguir entre la señal del transmisor y otras posibles señales. Esto permite al receptor saber en qué canal de todos los posibles está el transmisor.Tesi honetan proposatzen da Irrati Kognitiboaren (IK) paradigman oinarritutako MAC bat industriako haririk gabeko sentsore eta eragingailuen sareetarako. Sare horiek begizta itxiko kontrol aplikazioetarako erabili ohi dira, denbora eta sendotasunaren aldetik baldintza ugari eskatzen dute eta. Pertsonen osasuna eta makinak arriskuan ez jartzeko, beharrezkoa da sareak latentzia eta hutsegite tasa txikiak bermatzea. Gainera, industri giroetan lan egiteko direnez, esaterako, lantegietan edo garraioetan (trenak, hegazkinak, etab.), sare horiek gai izan behar dira gainazal metalikoek eragiten dituzten ibilbide aniztunaren eta itzal efektuaren ondorioz asko barreiatzen diren kanalei aurre egiteko. Ingurune horien ohiko ezaugarria da, baita ere, beste komunikazio sistema batzuen edo industriako makinen beraien interferentziak egotea. Tesi honetan proposatzen den MACa gai da honelako inguruetan lan egiteko denborari eta sendotasunari dagokienez eskatzen dituen baldintzak ziurtatzeko. IKan oinarrituta haririk gabeko sentsore eta eragingailu industrialen sareetarako MACa diseinatzeko prozesuan, horrelako sareetarako aurkeztu diren hainbat MAC alderatu dira. IKan oinarritutako MACak zein bestelakoak ebaluatu dira, eta IKak aplikazio hauetarako dituen abantailak ezarri dira. Ebaluaziorako Network Calculus erabili da, zeinaren bidez azterketa teoriko bat egin baita, eta azterketaren emaitzak OPNETen simulazioak eginda baliozkotu dira. Emaitzek erakusten dutenez, IKa gai da industriako inguruneetan interferentziak ekidin eta sendotasuna ziurtatzeko. Halere, aukeratu diren MACetatik batek ere ez du lortu baldintza biak, denborari buruzkoa zein sendotasunari buruzkoa, aldi berean ziurtatzea; interferentziak ekidin daitezke, baina ez aplikazioaren denborari buruzko baldintzak arriskuan jarri gabe. Dena dela, proposatu den MACak portaera determinista bat ziurtatzen du interferentziekiko, eta aldi berean denborari eta sendotasunari buruzko baldintzak ere ziurtatzen ditu. Hortaz, MAC hau egokia da sare mota honetarako. Sistemaren portaera determinista ziurtatzeko, handoff algoritmo berritzailea proposatu da, zeina interferentzia bat antzeman eta beste kanal bat igarotzeko gai den. Algoritmo hori aurretik ebaluatutakoa MACetako batekin batera erabiltzeko diseinatu da. Interferentzia antzeman eta beste kanal batera salto egitea denbora jakin batean egiten da, izan ere, sistema transmititzen ari dela antzeman baitaitezke interferentziak. Network Calculusen bitartez eta OPNETeko simulazioen bitartez ebaluatu da sistemaren errendimendua, eta proposatutako eskema erabiltzen ez denean MACak ematen dituen emaitzekin alderatu da. Alderaketa horretatik ondorioztatzen denez, handoff eskemak denborari eta sendotasunari buruzko baldintzak batera ziurtatzeko ahalmena ematen dio MACari. Gainera, tesiak azaltzen du inguruneari buruzko informazioa eskuratzeko MACak erabiltzen duen spectrum sensing algoritmoa, eta bere errendimendua MATLABen simulazioak eginez aztertu da. Bere sinpletasuna dela eta, energia detektore bat aukeratu da asmo honetarako. Modulazio sailkatzaile zikloegonkor bat ere aurkezten da. Sailkapen hori ahalik eta gehien sinplifikatu da benetako hardwarean inplementatu ahal izateko. Modulazioen sailkatzaileak OFDM, QPSK eta GFSK seinaleak bereizi ditzake. Bere errendimendua hargailuan dauden seinale eta akats desberdinetarako zehazten da, esaterako maiztasunaren offset-a,zuzenaren offset-a edo I/Q desorekak. Bukatzeko, spectrum sensing-eko algoritmoak baliozkotzeko erabili den plataforma kognitibo bat aurkezten da. IK4-Ikerlaneko eta Mondragon Unibertsitateko ikertzailez osatutako lantalde batek diseinatu du plataforma hori Xilinxen Virtex 6 FPGA baten oinarrutz. Plataformak spectrum sensing-eko bi algoritmo erabiltzen ditu eta Ethernet-RF zubi bat da. Bere helburua da Etherneteko kable bidezko lotura bat haririk gabeko batekin ordeztea industriako sentsore eta eragingailuen sareetan aplikatzeko. Spectrum sensing-eko algoritmoei esker, plataformak lotura sendoa bermatu dezake interferentziak gertatzen direnean. Energia detektorea transmisorean erabiltzen da informazioa transmititzeko erabilgarri egon daitezkeen kanalak aurkitzeko. Modulazioen sailkatzailea, berriz, hargailuan erabiltzen da transmisorearen seinalea eta egon daitezkeen beste seinale batzuk bereizteko. Horri esker, hargailuak badaki posible diren kanal guztietatik non dagoen transmisorea

Actas da 10ª Conferência sobre Redes de Computadores

Universidade do MinhoCCTCCentro AlgoritmiCisco SystemsIEEE Portugal Sectio

Towards video streaming in IoT environments: vehicular communication perspective

Multimedia oriented Internet of Things (IoT) enables pervasive and real-time communication of video, audio and image data among devices in an immediate surroundings. Today's vehicles have the capability of supporting real time multimedia acquisition. Vehicles with high illuminating infrared cameras and customized sensors can communicate with other on-road devices using dedicated short-range communication (DSRC) and 5G enabled communication technologies. Real time incidence of both urban and highway vehicular traffic environment can be captured and transmitted using vehicle-to-vehicle and vehicle-to-infrastructure communication modes. Video streaming in vehicular IoT (VSV-IoT) environments is in growing stage with several challenges that need to be addressed ranging from limited resources in IoT devices, intermittent connection in vehicular networks, heterogeneous devices, dynamism and scalability in video encoding, bandwidth underutilization in video delivery, and attaining application-precise quality of service in video streaming. In this context, this paper presents a comprehensive review on video streaming in IoT environments focusing on vehicular communication perspective. Specifically, significance of video streaming in vehicular IoT environments is highlighted focusing on integration of vehicular communication with 5G enabled IoT technologies, and smart city oriented application areas for VSV-IoT. A taxonomy is presented for the classification of related literature on video streaming in vehicular network environments. Following the taxonomy, critical review of literature is performed focusing on major functional model, strengths and weaknesses. Metrics for video streaming in vehicular IoT environments are derived and comparatively analyzed in terms of their usage and evaluation capabilities. Open research challenges in VSV-IoT are identified as future directions of research in the area. The survey would benefit both IoT and vehicle industry practitioners and researchers, in terms of augmenting understanding of vehicular video streaming and its IoT related trends and issues

Quality-Oriented Mobility Management for Multimedia Content Delivery to Mobile Users

The heterogeneous wireless networking environment determined by the latest developments in wireless access technologies promises a high level of communication resources for mobile computational devices. Although the communication resources provided, especially referring to bandwidth, enable multimedia streaming to mobile users, maintaining a high user perceived quality is still a challenging task. The main factors which affect quality in multimedia streaming over wireless networks are mainly the error-prone nature of the wireless channels and the user mobility. These factors determine a high level of dynamics of wireless communication resources, namely variations in throughput and packet loss as well as network availability and delays in delivering the data packets. Under these conditions maintaining a high level of quality, as perceived by the user, requires a quality oriented mobility management scheme. Consequently we propose the Smooth Adaptive Soft-Handover Algorithm, a novel quality oriented handover management scheme which unlike other similar solutions, smoothly transfer the data traffic from one network to another using multiple simultaneous connections. To estimate the capacity of each connection the novel Quality of Multimedia Streaming (QMS) metric is proposed. The QMS metric aims at offering maximum flexibility and efficiency allowing the applications to fine tune the behavior of the handover algorithm. The current simulation-based performance evaluation clearly shows the better performance of the proposed Smooth Adaptive Soft-Handover Algorithm as compared with other handover solutions. The evaluation was performed in various scenarios including multiple mobile hosts performing handover simultaneously, wireless networks with variable overlapping areas, and various network congestion levels

Cognitive radio systems in LTE networks

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University London.The most important fact in the mobile industry at the moment is that demand for wireless services will continue to expand in the coming years. Therefore, it is vital to find more spectrums through cognitive radios for the growing numbers of services and users. However, the spectrum reallocations, enhanced receivers, shared use, or secondary markets-will not likely, by themselves or in combination, meet the real exponential increases in demand for wireless resources. Network operators will also need to re-examine network architecture, and consider integrating the fibre and wireless networks to address this issue. This thesis involves driving fibre deeper into cognitive networks, deploying microcells connected through fibre infrastructure to the backbone LTE networks, and developing the algorithms for diverting calls between the wireless and fibre systems, introducing new coexistence models, and mobility management. This research addresses the network deployment scenarios to a microcell-aided cognitive network, specifically slicing the spectrum spatially and providing reliable coverage at either tier. The goal of this research is to propose new method of decentralized-to-distributed management techniques that overcomes the spectrum unavailability barrier overhead in ongoing and future deployments of multi-tiered cognitive network architectures. Such adjustments will propose new opportunities in cognitive radio-to-fibre systematic investment strategies. Specific contributions include: 1) Identifying the radio access technologies and radio over fibre solution for cognitive network infrastructure to increase the uplink capacity analysis in two-tier networks. 2) Coexistence of macro and microcells are studied to propose a roadmap for optimising the deployment of cognitive microcells inside LTE macrocells in the case of considering radio over fibre access systems. 3) New method for roaming mobiles moving between microcells and macrocell coverage areas is proposed for managing spectrum handover, operator database, authentication and accounting by introducing the channel assigning agent entity. The ultimate goal is to reduce unnecessary channel adaptation

Topology preservation and control approach for interference aware non-overlapping channel assignment in wireless mesh networks

The Wireless Mesh Networks (WMN) has attracted significant interests due to their fast and inexpensive deployment and the ability to provide flexible and ubiquitous internet access. A key challenge to deploy the WMN is the interference problem between the links. The interference results in three problems of limited throughput, capacity and fairness of the WMN. The topology preservation strategy is used in this research to improve the throughput and address the problems of link failure and partitioning of the WMN. However, the existing channel assignment algorithms, based on the topology preservation strategy, result in high interference. Thus, there is a need to improve the network throughput by using the topology preservation strategy while the network connectivity is maintained. The problems of fairness and network capacity in the dense networks are due to limited available resources in WMN. Hence, efficient exploitation of the available resources increases the concurrent transmission between the links and improves the network performance. Firstly, the thesis proposes a Topology Preservation for Low Interference Channel Assignment (TLCA) algorithm to mitigate the impact of interference based on the topology preservation strategy. Secondly, it proposes the Max-flow based on Topology Control Channel Assignment (MTCA) algorithm to improve the network capacity by removing useless links from the original topology. Thirdly, the proposed Fairness Distribution of the Non-Overlapping Channels (FNOC) algorithm improves the fairness of the WMN through an equitable distribution of the non-overlapping channels between the wireless links. The F-NOC is based on the Differential Evolution optimization algorithm. The numerical and simulation results indicate that the proposed algorithms perform better compared to Connected Low Interference Channel Assignment algorithm (CLICA) in terms of network capacity (19%), fractional network interference (80%) and network throughput (28.6%). In conclusion, the proposed algorithms achieved higher throughput, better network capacity and lower interference compared to previous algorithms