1- Introduction

2- Background overview and related work

3- Proposed systems

4- Proposed system evaluation

5- Conclusions

References

Abstract

Vehicular Ad hoc Networks (VANETs) have gained a great attention due to the rapid development of mobile Internet and Internet of Things (IoT) applications. On the other hand, the competition in the automotive industry has turned into an unprecedented race to who will be the first to provide the fully autonomous cars. However, the fully autonomous driving is still a bit far from deployment, and for now, they are providing automation only at a certain level and, at the same time, are offering connected services through their mobility service platforms. With Fog and Edge computing integrated in VANETs, these mobility platforms will be standardized to provide services for every car on the road, which will help VANETs to accomplish one of its main goals, the road safety. In this paper, we propose an intelligent Fuzzy-based Driver Monitoring System (FDMS) for safe driving. We present and compare two fuzzy-based systems: FDMS1 and FDMS2. To make a decision, FDMS1 considers Vehicle’s Environment Temperature (VET), Noise Level (NL) and Heart Rate (HR). While, for FDMS2, we consider Respiratory Rate (RR) as a new parameter to decide Driver’s Situational Awareness (DSA). We evaluate the ability of the driver to safely operate the vehicle by monitoring his condition and subsequently, based on the system output, a smart box informs the driver and provides assistance. We show through simulations and experiments the effect of the considered parameters on the determination of the driver’s situation and demonstrate the actions that can be performed accordingly.

Introduction

Every year the lives of approximately 1.35 million people are cut short as a result of a road traffic accident. Between 20 and 50 million more people suffer non-fatal injuries, with many incurring a disability as a result of their injury [1]. For years, in order to improve the road safety, many governments have undertaken initiatives by launching Intelligent Transport Systems (ITSs). ITS is a new road and traffic system which combines state-of-the-art information, communication, and control technologies to properly create an information network based on people, vehicles and roads. As a key part of ITS, the Vehicular Ad hoc Networks (VANETs) not only aim to help reducing the traffic accidents but also to enhance the traffic efficiency and the travel comfort of passengers and drivers. In VANETs, vehicles have networking capabilities and they send/receive valuable information such as safety warnings and traffic information to/from adjacent vehicles and roadside units (RSUs) via vehicle-to-vehicle (V2V) or vehicle-to-infrastructure (V2I) communication.

Software Defined Networking (SDN) has focused enormous attractiveness in changing conventional network by means of offering flexible and dynamic network management. It has drawn important concentration of the researchers from together academia and industries. Mainly, integrating SDN in Wireless Body Area Network (WBAN) applications specifies capable results in terms of handling with the issues like traffic management, security, energy efficiency etc. Recent improvements in miniaturization and energy efficient physiological sensor designs in SDN based Wireless Body Area Networks (WBANs) paved the way for health monitoring systems for collection and processing the real-time physiological data. The collection of signals from different sensor allows reliable diagnosis in heterogeneous than in homogeneous WBANs. Inspired by the evolutions of heterogeneous WBANs, a study on Wireless Electroencephalography Sensor Networks (WESNs) is carried out under distributed signal processing. The distributed WESNs are designed under two different hierarchy i.e. Hierarchical Fully-Connected Topology (HFCT) and Ad-Hoc Nearest-Neighbor Topology (ANNT) to improve the energy-efficiency using distributed Multi-channel Weighted Weiner Filter design (MW2F). Here, each module transmits linear combination of local channels with other modules. The power efficiency is improved Journal Pre-proof in MW2F signal processing algorithm by avoiding centralization of EEG data. A case study is carried out to test the reduced energy consumption after the removal of eye blink artifacts and it is tested with centralized counterparts. The MW2F is evaluated in both topologies against centralized environments and significant reduction of eye blink artifacts improves the energy efficiency in HFCT than other topologies.

Introduction

The energy efficient and miniaturization is the most hot research area in health monitoring systems, where the body is placed with several sensor nodes. These nodes can collect the EEG data and process it in real time and measures are considered to improve the energy efficiency. This system is called as Wireless Body Area Networks (WBANs) [1], and it offers higher demand in the area of physiological monitoring in hospital environment. The WBAN system is composed of several nodes with physiological sensors, wireless communication devices and a signal processing unit. These nodes can communicate with other sensor nodes placed over the body or it can be connected to a fusion center or a storage device. The signals collected from various resources are analyzed jointly in heterogeneous WBANs in real time environment for medical diagnosis.

In the last decade, there has been growing interest in Vehicular Ad Hoc NETworks (VANETs). Today car manufacturers have already started to equip vehicles with sophisticated sensors that can provide many assistive features such as front collision avoidance, automatic lane tracking, partial autonomous driving, suggestive lane changing, and so on. Such technological advancements are enabling the adoption of VANETs not only to provide safer and more comfortable driving experience but also provide many other useful services to the driver as well as passengers of a vehicle. However, privacy, authentication and secure message dissemination are some of the main issues that need to be thoroughly addressed and solved for the widespread adoption/deployment of VANETs. Given the importance of these issues, researchers have spent a lot of effort in these areas over the last decade. We present an overview of the following issues that arise in VANETs: privacy, authentication, and secure message dissemination. Then we present a comprehensive review of various solutions proposed in the last 10 years which address these issues. Our survey sheds light on some open issues that need to be addressed in the future.

Introduction

Several applications such as early warning systems which can warn about road construction, collisions, weather-related hazards, merging lanes, speed limits for curves, and pedestrian crossing warnings, are ready for the widespread deployment in Vehicular Ad-hoc NETworks (VANETs). Apart from assisting drivers to drive safely, VANETs can also provide infotainment to drivers/passengers for a more enjoyable driving as well as riding experience. Furthermore, VANETs can also assist in paying for parking and tolls, finding parking places, updating inbuilt vehicle navigation systems with real-time traffic situation, and downloading music, video and software updates [1–3]. VANETs can also assist law enforcement agencies in reconstructing accidents as well as reaching the location of the accidents faster. The general model of VANETs proposed in the literature consists of two major components: On Board Units (OBUs), installed on vehicles, and Road Side Units (RSUs) installed on roadside to support the infrastructure needed for the deployment of VANETs. Each vehicle is assumed to be equipped with a set of sensors to collect phenomena surrounding the vehicle; the OBU processes the information collected by the sensors and sends/receives them to/from other relevant vehicles directly or through nearby RSUs [4]. The RSUs may also connect to the Internet to provide the necessary services to vehicles. A broad range of applications can be enabled by two main types of communication: (i) infrastructurebased communication (Vehicle to Infrastructure (V2I) communication) and (ii) direct communication between vehicles (Vehicle to Vehicle (V2V) communication) [5] as shown in Fig. 1. Major efforts for standardizing VANETs communication protocols have been carried out by the IEEE 802.11 Task Group by defining enhancements to IEEE 802.11 required to support Intelligent Transportation Systems (ITS) applications. This amendment is currently known as IEEE 802.11p.

1- Introduction

2- Background

3- Problem formulation and solving strategy

4- Simulation results

5- Conclusion

References

Abstract

Vehicular ad-hoc networks provide essential Internet services to users. In consequence, mobile gateways are deployed to guarantee access to the Internet for the entire network. However, the selection of the best gateway taking into account some constraints and trying to reach some high-level objectives is a significant issue in mobile gateways discovery. The number of connected client vehicles must be maximized while a fair load distribution must be performed. For this purpose, we propose a multi-objective optimization system for mobile gateways selection based on two models using different solving strategies allowing the decision maker to choose the adequate solution. The solving approaches are evaluated and compared, and the simulations prove its efficiency compared to that found in the literature. The results show the effectiveness of the system in supporting a decision maker in solving a gateway selection problem and finding a fair solution in case there are no user preferences.

Introduction

In Vehicular Ad-hoc Networks (VANET), communication is established within a group of vehicles within the range of each other, this kind of connection is called Inter-Vehicle Communication (IVC). Furthermore, vehicles communicate with stationary types of equipment within the scope usually called road equipment, and we say that it is a Roadside-to-Vehicle Communication (RVC). The primary purpose of these vehicular networks is to help drivers and interested authorities by providing relevant information about the road. VANET is a useful technique in the so-called Intelligent Transportation Systems (ITS) and plays a role in improving road security and guaranteeing passenger comfort. Among the current challenges in ITS, we cite implementing real-time optimization and efficient systems. As a result, advances in cloud computing are used in this domain to enhance the services provided by ITS. The combination of these two fields becomes a massive research effort in the recent past [1]. Thanks to this union, new concepts are emerging such as vehicular cloud which provides all the services required by the autonomous vehicles [2]. Nowadays, it is possible to optimize the traffic control in the road thanks to many proposed applications deployed by information technology developers. However, cloud computing with its scalable access to computing resources represents a suitable solution for combining the Internet advantages and the technology improvements used on roads. Indeed, massive investment in hardware is not needed to implement the applications if cloud computing is merged to VANET as in [3,4].

1- Introduction

2- Related work

3- Preliminaries

4- Filter-based efficient request answering

5- Update a single filter

6- Filter cube construction and update

7- Experimental study

8- Conclusions

References

Abstract

Vehicles in urban city are equipped with more and more sensing units, and sensed data are continuously generated in large amount. These sensed data could be filtered and preprocessed before being shared or uploaded to the road side units and the cloud for efficiency. In this paper we propose a filter-based framework called FERA (Filter-based Efficient Request Answering), which combines the concept of fog computing and vehicular sensing, and adopts the pull/push strategies to adaptively and efficiently gather the requested data in vehicular ad hoc networks. Filters are defined based on the ratio of cost between the push and the pull methods to control the passage or blockage of the data readings. Moreover, filter cubes are defined to manage large number of filters, where efficient algorithms are developed to construct, update and store the filter cubes so that the matched data readings are pushed upward and unmatched data readings are blocked effectively. Extended simulated experiments demonstrate the proposed scheme has a much higher success ratio of request answering than existing schemes, e.g. REED (Abadiet al., 2005) and GeoVanet (Delotet al., 2011). Up to 94 percent of the requests could be successfully processed, while at the same time maintaining a relatively low query cost.

Introduction

Vehicular nodes are equipped with more and more sensing units, and large amount of sensing data such as GPS locations, speeds, video clips, and so on are generated [1,2]. These data are shared or uploaded as inputs for applications that aim at more intelligent transportations, emergency responses, and reduced pollutions and fuel consumptions. So cooperative urban sensing [3,4] is at the heart of the intelligent and green city traffic management. The key components of the platform will be a combination of pervasive vehicular ad hoc network and a central control and analyzing system. This has led to the emergence of a new kind of system, i.e. the Vehicular Ad-hoc Sensing System [5,6], where vehicles travel along roads and exchange information with encountered vehicles or nodes through V2V(vehicle to vehicle) or V2I (vehicle to infrastructure) communications. Data can be disseminated and reach a far distance by using moving vehicles as intermediates, following multi-hop routing protocols. Recently, IEEE 802 committee defined wireless communication standard IEEE 802.11p [7] that serves specifically for V2I communication. The Federal Communications Commission has allocated 75 MHz of bandwidth, which operates on 5.9 GHz channel for short range communications. One key and challenging issue in VANET is the vehicular data gathering [2,8–10]. First, vehicular nodes are limited to road topology while moving, and under various road conditions and high moving speeds the network usually suffers rapid topology and density changes. The communications are usually fragmented and intermittent-connected. Second, the vehicular sensed data is in large amount and characterized as continuous generation. The sensed data should be filtered and preprocessed before being shared or uploaded. Data filtering technologies tailored to the VANET environment are highly needed. Generally speaking, there are two strategies to gather data: the push-based and the pullbased models, which are similar to those strategies used in the field of distributed and mobile databases. In a push-based model, each vehicle senses the data and proactively to upload data to a central server through V2V or V2I communications [11,12]. So when a node receives information from its neighbors, it has to decide whether that information is relevant or not.

I- Introduction

II- Cluster-based Algorithms in Wireless Ad-hoc Networks

III- Routing Algorithms for Wireless AD HOC Network Simulation

IV- EESOA reviewed

V- SIMULATION

References

Abstract

One of the main issues of routing protocols on wireless ad-hoc networks is the energy consumed by the traffic generated in the route discovery and routing table construction and maintenance. To reduce such of amount messages, we propose to use a backbone structure which would control the network traffic flow in an energy-efficient manner. This paper proposes the implementation of the energy-efficient selforganized algorithm (EESOA) as Medium Access Control (MAC) protocol. Also, we extended the algorithm to address network segmentation by handling inter clusters connectivity. EESOA as MAC provide a backbone structure for wireless ad-hoc networks due to their cluster-based capabilities and robustness to topology changes. The encapsulation of EESOA on MAC provides a cross layer solution, agnostic to the routing protocol and wireless technology. To show the performance of this cross-layer solution, an implementation of a wireless ad-hoc network with AODV and EESOA as MAC protocol in the NS3 simulator is used. This simulation allows evaluating the performance of the AODV routing protocol over EESOA as MAC protocol compared against normal Ad-hoc MAC. Therefore, the use of routing protocol over a self-organized algorithm can obtain better results, in packet loss, network connectivity and node reachability.

INTRODUCTION

Wireless networks can be categorized in infrastructure-based and infrastructure-less wireless networks, also called wireless ad-hoc networks. Wireless ad-hoc network consists on two or more wireless devices able to communicate with each other without any centralized administrator. Each node works as both a host and a router although they have less computational capabilities [1]. The network topology is dynamic because the connectivity among nodes vary with time due to node mobility, node departures and new node arrivals [2]. Ad-hoc networks are decentralized, nodes are connected in heterogeneous manner using wireless links [3]. Adhoc network introduces terms such as distributed, resourceconstrained, self-organized and infrastructure-less [4]. Resource constrains distinct ad-hoc networks on hardware and energy limitations when compared with wired networks.

1- Introduction

2- 5G security

3- VANET security: Requirements, threats, attacks, and standards

4- Seamless integration of VANET and 5G security

5- Future challenges and research opportunities

6- Conclusion

References

Abstract

The commercial adaptation of Vehicular Ad hoc NETwork (VANET) to achieve secure Intelligent Transportation System (ITS) heavily depends on the security guarantees for the end-users and consumers. Current VANET security standards address most of the security challenges faced by the vehicular networks. However, with the emergence of 5th Generation (5G) networks, and the demand for a range of new applications and services through vehicular networks, it is imperative to integrate 5G and vehicular networks. To achieve a seamless integration, various design and implementation issues related to 5G and VANETs must be addressed. We focus on the security issues that need to be considered in order to enable the secure integration of 5G and VANETs. More precisely, we conduct in-depth study of the current security issues, solutions, and standards used in vehicular networks and then we identify the security gaps in the existing VANET security solutions. We investigate the security features of 5G networks and discuss how they can be leveraged in vehicular networks to enable a seamless and efficient integration. We also propose a security architecture for vehicular networks wherein the current VANET security standards and 5G security features coexist to support secure VANET applications. Finally, we discuss some future challenges and research directions for 5G-enabled secure vehicular networks.

Introduction

Over the last couple of decades, the automotive industry has been the hotbed of technological innovation as a result of significant advances in computation, communication, and storage technologies. The main drivers behind such inno vations stem from the problems faced by the transportation systems. Every year, thousands of people lose their lives and billions of dollars are spent on medical bills and insurance costs. These huge costs have led to the development of a wide range of new transportation technologies which can enable a safe and comfortable driving experience and provide additional value-added  services to both drivers and passengers [1]. In this context, the Intelligent Transportation System (ITS) promises a secure and reliable driving experience by employing vehicles to communicate with each other and with the environment that includes both infrastructure and the pedestrians. In other words, ITS is achieved through Vehicular Ad hoc NETwork (VANET) where vehi cles communicate with the environment through Vehicle-to-Everything (V2X) communication paradigm [2]. V2X includes Vehicle-to-Vehicle (V2V), Vehicleto-Infrastructure (V2I), Vehicle-to-Pedestrian (V2P), Vehicle-to-Cloud (V2C) communications and so on [3, 4].

1- Introduction

2- Related literature

3- The MIoT paradigm

4- CDS: a crawler tailored for MIoTs

5- Analytical discussion

6- Conclusion

References

Abstract

The Internet of Things (IoT) is currently considered the new frontier of the Internet, and a lot of research results about this topic can be found in the literature. One of the most effective ways to investigate and implement IoT is based on the use of the social network paradigm: Social Internet of Things (SIoT) is an excellent attempt in this direction. In the last years, social network researchers have introduced new paradigms capable of capturing the growing complexity of this scenario. One of the most known of them is Social Internetworking System, which models a scenario comprising several related social networks. In this paper, we investigate the possibility of applying the ideas underlying Social Internetworking System to IoT, and we propose a new paradigm, called MIoT (Multiple Internets of Things), capable of modeling and handling the increasing complexity of this last context. Furthermore, in order to facilitate knowledge extraction and exploitation in presence of a huge number of things, we also propose a crawler specifically designed for an MIoT. Finally, through an experimental campaign, we show that classical crawlers are not adequate for MIoTs, whereas our own is well suited and outperforms all of them in this context.

Introduction

The Internet of Things can be considered as an evolution of the Internet, based on the pervasive computing concept [9]. In the past, several strategies to implement the IoT paradigm and to guarantee ubiquitous computing have been proposed [24, 66, 16]. One of the most effective of them is based on the use of the social networking paradigm [7, 10, 8]. In this case, IoT is represented as a social network and, thanks to this association, Social Network Analysis-based models can be used to empower IoT. One of the most advanced attempts in this direction is SIoT (Social Internet of Things). In SIoT, things are empowered with social skills, making them more similar to people [7, 10]. In particular, they can be linked by five kinds of relationship, namely: (i) parental object relationship; (ii) colocation object relationship; (iii) co-work object relationship; (iv) ownership object relationship; (v) social object relationship. If: (i) a node is associated with each thing, (ii) an edge is associated with each relationship between things, and, finally, (iii) all the nodes and the edges linked by the same relationship are seen as joined together, SIoT can be modeled as a set of five pre-defined networks. Here, some nodes belong to only one network (we call them inner-nodes), whereas other ones belong to more networks (we call them cross-nodes). The idea underlying SIoT is extremely interesting and, as a matter of fact, has received, and is still receiving, a lot of attention in the literature. However, we think that, in the next future, the number of relationships that might connect things could be much higher than five, and relationships could be much more variegate than the ones currently considered by SIoT. As a consequence, we think that a new paradigm, taking into account this fact, is in order.

The failure detector is one of the fundamental components for maintaining high availability of Vehicular Ad-hoc Networks (VANETs). However, the dynamic nature of VANETs caused by the high mobility of vehicles and communication link failures has a serious impact on the performance of failure detection. Therefore, it is very meaningful to design a suitable failure detector that can deal with the dynamic nature of VANETs well. In this paper, we propose a hierarchical failure detector based on the architecture of VANETs. This failure detector can adapt to the dynamic network conditions and meet the different Quality of Service (QoS) requirements of multiple applications in VANETs. Different from existing failure detectors, we propose a failure detector that employs a detection-result sharing mechanism and groups the nodes according to the architecture of VANETs. We evaluate our proposed failure detector by using NS2 and GT-ITM to simulate the work environment of VANETs. The experimental result shows that our proposed failure detector can improve the detection time by at most 45% and the detection accuracy by at most 25% under similar detection overhead.

Introduction

Vehicular Ad-hoc Networks (VANETs) are dynamic, nonstructured, self-organizing networks with asynchronous and distributed characteristics, and the nodes (vehicles) move at high speeds compared to other mobile ad-hoc networks (MANETs) [1]–[3]. The main purpose of VANETs is to provide a medium for intervehicular communication allowing for intervehicle (V2V) and vehicle to roadside infrastructure (V2R) data exchange, with multiple applications for Intelligent Transportation Systems (ITS). One of the important features is the high mobility of vehicles in VANETs; vehicles can suddenly quit or enter the network, and communication links among vehicles may suffer from signal degradation due to obstacles, changes in vehicle densities, etc. [4]–[6]. For the ITS applications running on VANETs, VANETs must be fault-tolerant to mitigate communication problems among network nodes so that decisions can be made safely and with confidence [7]. The failure detector plays a key role in a fault-tolerant system [8]. By periodically detecting the status of nodes in systems, it can provide information to achieve routing recovery, application deployment, real-time communication, etc. Thus, the high availability of VANETs can be guaranteed. An effective failure detector can provide information regarding suspected nodes in a timely and accurate manner so that correction actions can be performed as soon as possible. At present, there are numerous studies related to failure detectors in distributed systems [9]–[13].

1- Introduction

2- Related work

3- Base components of hybrid scheme

4- The hybrid scheme

5- Simulation environment

6- Attributes analysis of hybrid scheme

7- Performance evaluation

8- Conclusions

References

Abstract

Over the past few years, there has been growing research interests on vehicular ad hoc networks (VANETs) due to their ease of deployment and the potential support for wide range of applications that can greatly enhance our everyday driving experience. Multi-hop messaging is expected to be the primary mode of communication among vehicles in numerous VANET-based applications including road safety, traffic management and infotainment services. Proper selection of the next-hop relay nodes is an essential part in the design of multi-hop message dissemination schemes in VANETs, which highly governs the reception of the broadcasted messages, especially when evaluated over large coverage distances and high node density networks. Existing message dissemination schemes adopt only a single relay nodes selection criterion for choosing nodes in the group of next-hop relays. However, potential of the selected relay nodes can be restricted due to exploiting only a single selection criterion, hence limiting the performance outcomes. This research proposes a new class of hybrid relay nodes selection scheme that attempts to exploit the best features of existing message dissemination protocols, in terms of message reachability, communication delay and bandwidth utilization, while avoiding their shortcomings. The new hybrid scheme takes into account the spatial distribution of the next-hop relay nodes with reference to the current sending node. To the best of our knowledge, the present study is the first in literature to propose such a hybrid scheme that attempts to improve performance of VANETs over varying node densities, traffic load conditions and mobility speed scenarios. Over the most stringent communication scenario considered in this work, our performance analysis indicates that the new hybrid scheme improves reachability by up to 10% compared to the most competitive conventional versions. This improvement is obtained while having a marginal performance fall in terms of the end-to-end communication delays and messages saved rebroadcast ratios.

Introduction

Enabling direct wireless communication among vehicles is a core component of the envisioned Intelligent Transportation Systems (ITS) [1-3]. The directly connected vehicles are commonly referred to as Vehicular Ad Hoc NETworks (VANETs) [4-6]. The endorsement of information and communication technologies in vehicles can enhance drivers’ awareness of immediate and far distant traffic situations. Consequently, VANETs can lead towards more intelligent decisions to deal with the dynamic road-related events [1, 3]. VANETs can support a wide spectrum of applications including road safety services, traffic flow and congestion management [7, 8]. On top of that, it is envisaged that VANETs will become the de-facto enabling technology for communication among vehicles on the road [9]. Multi-hop messaging is expected to be the primary mode of communication in VANETs that can be utilized for diversified set of applications [1, 10]. In particular, a timely and successful reception of messages can be used for the reduction of high speed road accidents by providing early warning messages to nearby and far distant vehicles, hence increasing the reaction time to the advertised situations [11]. VANETs can facilitate small to large propagation areas for the broadcasted messages through multi-hop mode of communication, with coverage distances spanning from few hundred meters to several kilometers [12]. Proper selection of relay nodes is an essential part in the design of multi-hop message dissemination schemes, which highly governs the reception of the broadcasted messages, especially when propagated over large coverage distances and high node density networks [13-15]. A poor selection of the relay nodes can lead to the loss of messages, hence significantly limiting the reception of messages. The success and failure in relay nodes selection becomes even more critical when the broadcasted messages are critical-in-nature, such as accident advertising alert messages.

1- Introduction

2- Related work

3- Proposed IoT architecture

4- IoT applications

5- Simulation and result

6- Conclusion

References

Abstract

Converging of MANET with WSN used in ubiquitous smart environments opens new prospect in monitoring the large scale urban area and makes a new communication platform for different applications in Internet of Things (IoT) domain. Sensors used for IoT applications, sense the environment and send the data to the gateway node, which in turn send the collected data to the MANET node, especially used for data harvesting. Here we considered two IoT applications which are monitored by wireless sensor nodes. The challenging part of this work is to make a platform by converging sensor network with the MANET network because nodes have different power levels, heterogeneous protocols and have chances of co-channel interferences. We proposed a total solution which includes network protocols, spectrum distribution, node deployment, MANET routing and mobility pattern and finally implementation of the IoT applications which are simulated using Omnet++ simulator and shown their performances and feasibility.

Introduction

A recent paradigm of communication which popularly known as Internet of Things (IoT), where all the objects of different kinds of our daily life spanning from smart phones, sensors or devices are associated with network enabled objects (like RFID) can communicate with each other and makes a part of Internet. The main aim of IoT is to make Internet more and more inspiring and pervasive. By connecting wide variety of heterogeneous devices and making easy access of the devices, several applications are being used in IoT, which deals with the large number of data generated by the attached devices and make some decisions which is very important for the industry or control the attached devices based on the generated data. There is a huge use of IoT in several domains like medical aids, home automation, industrial automation, mobile health care, electricity transmission and distribution etc. Now a day smart cities are one of the emerging domain of IoT, where researchers are proposing several communication models and standards and provide some applications which facilitate the residing citizens by enhancing their everyday standard of life. With the advancement of communication technology and microcontroller technology, Wireless Sensor Network (WSN) plays an important role in IoT. Sensor nodes, which are very tiny low cost devices, can sense different parameters in the environment, it can store data in its memory temporarily and can communicate with other electronics devices by using communication technology like IEEE802.15.4 or Bluetooth Low Energy (BLE). On the other hand RFID tag is also a useful device in IoT, which is used to identify an object attached with a RFID tag. In our work, MANET plays a vital function, which is used as the backbone of the IoT network. Due to its inherent properties, the MANET nodes can build spontaneous connections with other nodes without the need of any infrastructure. MANET nodes can move around the IoT network and collect data from the sensors, RFID attached nodes, or any fixed Wireless nodes. Thereafter it can process the data and send it to the Internet gateway through some intermediate MANET nodes. The MANET nodes use the efficient path to reach one of the available Internet gateways. Like sensor nodes, MANET nodes can be used as key technologies in several applications in IoT.

The reliability of the mobile ad hoc network (MANET) is receiving increasing attention. Previous works are mainly focused on the connectivity reliability of the MANET; however, its performance reliability has not been considered. In the MANET, the paths connecting two nodes are prone to continuous changes due to the mobility of nodes, which can result in a huge uncertainty on the transmission performance. Thus it is necessary to research the evaluation method of the performance reliability of the MANET. In this study, the transmission reliability is defined to measure the reliability of the transmission performance of the MANET. The impact of interference on the transmission reliability is considered. The topology optimization of the MANET is studied based on the transmission reliability, and genetic algorithm is adopted to solve the optimization problem. In the numerical example, the effects of the involved parameters on the transmission reliability are discussed, and some applicable conditions of the optimal design are analyzed for practical applications.

Introduction

The mobile ad hoc network (MANET) is an emerging communication technology [1]. Its flexible and easy deployment has attracted different application areas, such as military [2], disaster recovery [3] and vehicular communication [4]. In simple terms, the MANET is an autonomous wireless network without fixed infrastructure, and it consists of nodes which can move dynamically [5]. A link (or called a hop) between two nodes exists if both nodes are in the communication range of each other. Multi-hop communication is popularly applied in the MANET to increase the overall network capacity and performance [6]. A multi-hop path connecting two nodes can be established by taking other nodes as relay nodes. Network reliability refers to the probability that the function of a network can meet the use requirement, and it is an important index to weigh network performance [7]. Network reliability has been researched in many fields, such as communication [8], transportation [9] and electric power [10], to design new systems or improve existing systems. The connectivity reliability and the performance reliability are two branches of network reliability, and both of them are important for the reliability evaluation of networks [11]. The connectivity reliability mainly studies the topology structure of networks, and it is defined as the probability that a certain set of nodes in a network are connected [12]. The performance reliability is related to network performance, such as transmission delay for a communication network, and it is defined as the probability that the performance of a network can meet the use requirement [11]. Recently, the reliability of the MANET is receiving increasing attention. Most of the previous works are focused on the connectivity reliability. Such studies include Cook and Ramirez-Marquez [13-18], Padmavathy and Chaturvedi [19-21], Kharbash and Wang [22], Chen et al. [23], Wang [24], etc. However, for the MANET, it is untrue that a high connectivity reliability can guarantee an excellent transmission performance, and it is one-sided to evaluate the reliability by only considering the connectivity reliability [11]. In the MANET, the paths connecting two nodes are prone to continuous changes due to the mobility of nodes, which can result in a huge uncertainty on the transmission performance [25]. The connectivity reliability measures the ability of the MANET to maintain the connectivity of nodes. Two nodes are connected as long as there are paths between them. However, the connectivity reliability cannot reflect the effect of the change of paths on the transmission performance. If the paths connecting two nodes vary frequently, communication interruptions may often occur between the nodes, and the transmission performance may be unsatisfactory. Therefore, it is needed to consider the performance reliability of the MANET.

The secrecy throughput capacity (STC) performance study of mobile ad hoc networks (MANETs) is critical for supporting their applications in securitysensitive scenarios. Despite much work on the scaling law results of MANET STC, the exact STC study of such networks remains an open problem. This paper, for the first time, investigates the exact STC of a cell-partitioned MANET with group-based scheduling scheme from the physical layer (PHY) security perspective. We first propose two secure transmission schemes based on the PHY security technology, i.e., secrecy guard zone based and cooperative jamming based schemes. The secrecy guard zone based scheme allows transmissions to be conducted only if no eavesdroppers exist in the secrecy guard zone around transmitters. The cooperative jamming based scheme utilizes non-transmitting nodes to generate artificial noise to suppress eavesdroppers in the same cell, such that transmissions can be conducted only if all eavesdroppers in the transmission range are suppressed. We then derive exact analytical expressions for the STC performance of the concerned network under both secure transmission schemes based on the analysis of two basic secure transmission probabilities. Finally, extensive simulation and numerical results are provided to corroborate our theoretical analysis and also to illustrate the STC performance of the concerned MANET.

Introduction

As wireless communication technology evolves continuously, mobile ad hoc networks (MANETs) have been highly appealing for supporting lots of critical applications such as military battlefield, emergency rescue, disaster relief, etc. However, due to the open nature of wireless medium, wireless communication is vulnerable to eavesdropping attacks by unauthorized receivers (eavesdroppers), posing a great threat to the security of MANETs. Traditionally, the security of wireless communications is guaranteed by cryptography, which relies on solving various computationally difficult problems (e.g., RSA problem [1], CDH problem [2], DLP problem [3]). Recently, another promising security approach, called physical layer (PHY) security [4–6], has been proposed to provide a stronger security guarantee by exploiting the inherent physical properties of wireless channels, such as noise, interference, and time-varying fading. As adversaries (eavesdroppers) may have no enough computing power, they can hardly solve the difficult problems in the cryptography as of today. Thus, cryptographic approaches are still the main practical and effective security methods for wireless networks nowadays, and in most cases the PHY security technology is regarded as a complement for cryptography to improve the achieved security. However, as the computing power of eavesdroppers develops (for example, they can conduct the quantum computing [7]), current cryptographic methods may face the increasingly high risk of being broken. By then, the PHY security technology may be widely applied to provide a strong form of security guarantee for wireless networks. Compared to cryptography-based methods, the PHY security technology can provide an everlasting security guarantee without the need of costly secret key management/distribution and complex cryptographic protocols. Therefore, although the PHY security technology usually comes with a reduced throughput, it is still envisioned to be a promising security mechanism for MANETs. This paper focuses on the secrecy throughput capacity (STC) issue in MANETs, which is essentially equivalent to the fundamental and long-standi ng throughput capacity problem (see [8, 9] and the references therein) under the consideration of PHY security. This metric characterizes the maximum achievable rate per node at which a source packet can be transmitted to the destination both reliably and securely. Extensive research efforts have been devoted to the STC study of wireless ad hoc network [10–16] (Please refer to Section 2 for related works). It is notable that these works focus on deriving the scaling law results, which are certainly important to characterize how the STC of a MANET scales up as the network size tends to infinity. However, as the above scaling law results are usually functions of only the network size, they can hardly reflect the impacts of other key parameters of protocols and schemes on network performances. In addition, scaling law results are usually regarded as a retreat when exact results are out of reach [9], which reveals that exact STC results are more deserved and critical to facilitate the design, development and commercialization of MANETs. Unfortunately, such exact STC study for MANETs remains an open problem in the literature.