Software‐defined network‐enabled opportunistic offloading and charging scheme in multi‐unmanned aerial vehicle ecosystem

Unmanned aerial vehicles (UAVs) are autonomous fliers, which can play different roles in modern day applications. In one of the important role, UAVs can act as aerial data forwarding nodes for communication range enhancement in remote areas. UAVs form a web of drones, which can be geo‐distributed across a large area to serve various applications. However, the two major contradicting challenges with respect to multi‐UAV networks are channel congestion and flight time enhancement. The use of effective data transmission techniques to handle congestion can lead to higher battery dissipation, which in turn end up in the reduction in flight time. However, it is utmost necessity to provide an effective framework, which can provide a viable solution for handling congestion in multi‐UAV networks while enhancing the flight time of UAVs. To handle these issues, software‐defined network (SDN)–enabled opportunistic offloading and charging scheme (SOOCS) in multi‐UAV ecosystem is designed in this paper. In this scheme, an opportunistic offloading scheme is proposed, which uses an SDN‐based control model to handle congestion issues. Apart from this, an opportunistic energy‐charging scheme is designed, wherein the UAVS can either replenish their batteries using solar plates or they can wirelessly charge energy from charging points deployed at various geo‐distributed locations. The proposed scheme is evaluated using a simulation‐based study over the realistic deployment of charging points in Chandigarh City, India. The results obtained show the superiority of SOOCS over other variants of its category in terms of end‐to‐end delay, throughput, and hand‐over latency.     

A multi‐channel cooperative clustering‐based MAC protocol for V2V communications

The Internet of vehicles (IoV) is an emerging networking technology, which can support information sharing and interactions among users, vehicles, and infrastructures. Various applications can be provided by IoVs, and they have very different quality‐of‐service (QoS) requirements. It is a great challenge to design an efficient MAC protocol to meet the different QoS demands of various applications in IoVs, because of unreliable links and high vehicle mobility. On the other hand, cooperative communication is effective in mitigating wireless channel impairments by utilizing the broadcast nature of wireless channels. In this paper, a multi‐channel cooperative clustering‐based MAC (MCC‐MAC) protocol, under the Dedicated Short Range Communication (DSRC) multi‐channel architecture, is presented to improve the transmission reliability of safety messages and provision QoS for different applications in IoVs. Further, we analyze the performance of MCC‐MAC, in terms of average transmission delay. In addition, extensive simulations with ns‐2 are conducted to demonstrate the performance of the proposed MCC‐MAC. Copyright © 2016 John Wiley & Sons, Ltd.     

A multi‐access method for BPL based on orthogonal pulse division multiplexing,barker‐code‐based spectrum spreading and orthogonal frequency division multiplexing

A highly efficient multi‐access scheme of broadband power line (BPL) communication, named as OFDM‐BPS‐OPDMA, is proposed based on the Orthogonal Pulse Division Multiplexing Access (OPDMA), Barker‐code‐based Spectrum Spreading (BSS) and Orthogonal Frequency Division Multiplexing (OFDM) method. The orthogonal pulses are generated by using the eigenvectors of Hermitian matrix. At the same time, a specific pulse will be allocated to every user of the communication system. The transmitting data are first modulated by OFDM. Then, it is processed with OPDMA and BSS. Finally, the data is sent to the power line channel. On the receiving side, the data is processed with BSS demodulation, OPDMA demodulation and OFDM demodulation, and the receiving data for each user is acquired. Because of the orthogonality between these pulses, the multi‐user interference could be eliminated; when BSS is used, the waveform restoration is enhanced. Meanwhile, with the help of OFDM, the multi‐path interference is mitigated. Particularly, all users can share the resources of time and spectrum without interfering with others, and get excellent reliability in the concerned scheme. When OFDM is used, the sub‐carriers may be allocated dynamically, and the legal radio frequency band could be shunned by sharing the common bandwidth with other communication systems. Copyright © 2009 John Wiley & Sons, Ltd.     

Secured routing in wireless sensor networks using fault‐free and trusted nodes

Wireless sensor network (WSN) should be designed such that it is able to identify the faulty nodes, rectify the faults, identify compromised nodes from various security threats, and transmit the sensed data securely to the sink node under faulty conditions. In this paper, we propose an idea of integrating fault tolerance and secured routing mechanism in WSN named as fault tolerant secured routing: an integrated approach (FASRI) that establishes secured routes from source to sink node even under faulty node conditions. Faulty nodes are identified using battery power and interference models. Trustworthy nodes (non‐compromised) among fault‐free nodes are identified by using agent‐based trust model. Finally, the data are securely routed through fault‐free non‐compromised nodes to sink. Performance evaluation through simulation is carried out for packet delivery ratio, hit rate, computation overhead, communication overhead, compromised node detection ratio, end‐to‐end delay, memory overhead, and agent overhead. We compared simulation results of FASRI with three schemes, namely multi‐version multi‐path (MVMP), intrusion/fault tolerant routing protocol (IFRP) in WSN, and active node‐based fault tolerance using battery power and interference model (AFTBI) for various measures and found that there is a performance improvement in FASRI compared with MVMP, IFRP, and AFTBI. Copyright © 2014 John Wiley & Sons, Ltd.     

Tree‐based channel assignment schemes for multi‐channel wireless sensor networks

Many sensor node platforms used for establishing wireless sensor networks (WSNs) can support multiple radio channels for wireless communication. Therefore, rather than using a single radio channel for whole network, multiple channels can be utilized in a sensor network simultaneously to decrease overall network interference, which may help increase the aggregate network throughput and decrease packet collisions and delays. This method, however, requires appropriate schemes to be used for assigning channels to nodes for multi‐channel communication in the network. Because data generated by sensor nodes are usually delivered to the sink node using routing trees, a tree‐based channel assignment scheme is a natural approach for assigning channels in a WSN. We present two fast tree‐based channel assignment schemes (called bottom up channel assignment and neighbor count‐based channel assignment) for multi‐channel WSNs. We also propose a new interference metric that is used by our algorithms in making decisions. We validated and evaluated our proposed schemes via extensive simulation experiments. Our simulation results show that our algorithms can decrease interference in a network, thereby increasing performance, and that our algorithms are good alternatives for static channel assignment in WSNs. Copyright © 2015 John Wiley & Sons, Ltd.     

VDNet: an infrastructure‐less UAV‐assisted sparse VANET system with vehicle location prediction

Vehicular Ad Hoc Network (VANET) has been a hot topic in the past few years. Compared with vehicular networks where vehicles are densely distributed, sparse VANET have more realistic significance. The first challenge of a sparse VANET system is that the network suffers from frequent disconnections. The second challenge is to adapt the transmission route to the dynamic mobility pattern of the vehicles. Also, some infrastructural requirements are hard to meet when deploying a VANET widely. Facing these challenges, we devise an infrastructure‐less unmanned aerial vehicle (UAV) assisted VANET system called V ehicle‐D rone hybrid vehicular ad hoc Net work (VDNet), which utilizes UAVs, particularly quadrotor drones, to boost vehicle‐to‐vehicle data message transmission under instructions conducted by our distributed vehicle location prediction algorithm. VDNet takes the geographic information into consideration. Vehicles in VDNet observe the location information of other vehicles to construct a transmission route and predict the location of a destination vehicle. Some vehicles in VDNet equips an on‐board UAV, which can deliver data message directly to destination, relay messages in a multi‐hop route, and collect location information while flying above the traffic. The performance evaluation shows that VDNet achieves high efficiency and low end‐to‐end delay with controlled communication overhead. Copyright © 2016 John Wiley & Sons, Ltd.     

Bandwidth allocation and distributed relay selection for multiple‐user and multiple‐relay cooperative systems using Stackelberg game

Cooperative communication is an ongoing research area which lies on the basic idea of transmission of information from the transmitter to the receiver with the assistance of a virtual array of relay nodes in between, which will eventually provide the spatial diversity. This paper deals with the resource allocation (bandwidth in this case) among multiple users (source‐ destination pairs) in a cooperative communication environment along with the relay selection when there are multiple relay nodes to assist the transmitting nodes to pass on their data signal to respective receivers. A multi‐user, multi‐relay system model is considered here on which Amplify‐and‐Forward relaying scheme is applied. The bandwidth allocation and relay selection are done based on the Stackelberg game according to which transmitting nodes are treated as purchasers and relaying nodes are treated as vendors. By this planned approach, the transmitting nodes can discover the relays at comparatively better positions and can purchase the optimal bandwidth from those helping relays. By this approach, the relays which are competing with each other can increase their own utilities by demanding the optimal prices and the multiple users which are competing with each other can maximize their own utilities by demanding the optimal bandwidths. Distributed relay selection scheme is applied here which does not require precise information of channel state information as opposed to Centralized scheme and it gives comparable results, too.     

Distributed spatial–temporal precoding with limited feedback in MIMO multi‐relay systems

Precoding techniques can be introduced into multi‐relay systems due to the similarity between cooperative communication systems and traditional multi‐input–multi‐output (MIMO) systems. In this paper, a channel state information (CSI) feedback scheme based on the zero‐forcing (ZF) relaying protocol is proposed at first, where the information of relaying channel and noise related to each relay node can be compressed into two positive real parameters. Then, based on the proposed feedback scheme, the singular‐vector‐based local temporal precoder is presented at the source node through two continuous transmitted vectors, which is termed as distributed spatial–temporal precoding (DSTP). Moreover, various spatial data rates can be conveniently supported by DSTP. Based on the analysis on DSTP, it is better that the number of data streams is not larger than the number of antennas equipped at the source node. The unitary DSTP with the proposed feedback scheme outperforms not only the close‐loop direct transmission but also the simple ZF relaying method. Copyright © 2010 John Wiley & Sons, Ltd.     

Reducing wireless multi‐hop delay via RSU re‐routing in vehicular wireless networks

Vehicular wireless networks offer wireless multi‐hop communications between vehicles and roadside units (RSUs). To reduce deployment cost, the distance between two RSUs could be long; that is, the communications between an RSU and a vehicle may be carried out through multi‐hops among intermediate vehicles. When a vehicle is driven from one RSU to another, the wireless multi‐hop delay becomes more serious as the number of multi‐hop relays increases. The wireless multi‐hop delay is critical for some emergency service. For instance, in a traffic accident, when a patient was sent to the hospital by ambulance, the life information of the patient must be transmitted to the hospital on time through the multi‐hop wireless network. If the ambulance is moved from one RSU to another, the wireless multi‐hop delay becomes more and more serious as the ambulance is closing to another RSU. In this paper, we propose an RSU re‐routing strategy that dynamically alters multi‐hop communications until the best RSU with the shortest path using location information is found. Moreover, we compare the proposed strategy with the existing strategy in terms of broadcasting costs, re‐routing delay, and wireless multi‐hop delay of data transmission. Performance results show that the proposed strategy can reduce the wireless multi‐hop delay significantly. Copyright © 2014 John Wiley & Sons, Ltd.     

A multi‐agent self‐adaptative management framework

The self‐management vision, which has raised much interest in recent years, is only an operational aim that does not provide any solution in its definition on how to attain this management autonomy. The general contribution of this article suggests concepts, methods and mechanisms to conceive a self‐adaptative management framework, thus participating in this self‐management vision. This framework is composed of organizational aspects based on multi‐agent concepts, informational aspects based on different management ontologies and cooperative aspects based on specific agent behaviours which automate the accomplishment of management actions on the overall distributed environment. We have also implemented a prototype of this work to validate the feasibility of our approach and confirm the self‐adaptation capacities of the system. Copyright © 2008 John Wiley & Sons, Ltd.     

An extended core‐based framework for delay‐constrained group communication

Multipoint communications is the simultaneous transmission of data streams from a number of sources to a set of receivers in a group according to predetermined metrics. The core‐based approach in multipoint communication enhances potential solutions in terms of quality‐of‐service (QoS)‐efficiency and feasibility of the results in inter and intra‐domain routing. In this paper, we first analyse the solution space for constrained multipoint communication problems under the core‐based approach. We show that the range of solutions examined by the models proposed to date is restricted to a subset of the entire solution space, which restricts the potential efficiency of the results. We propose SPAN, a core‐based framework processing on our identified extended solution space for constrained multi‐source group applications. SPAN consists of core selection and tree construction as two modular components complimenting one another to achieve more efficient solutions in distributed processing. SPAN is also asymmetric, hence potentially operates in domains in which link weights are not necessarily equal in both directions. We analyse the computational and message complexity of our framework and show its feasibility for distributed deployment. Our performance results show that SPAN consistently outperforms its counterparts in the literature in terms of cost and QoS‐efficiency. Copyright © 2007 John Wiley & Sons, Ltd.     

Content Protective Multi‐Agent Platform for MsMu Service and Pattern‐Based Content Management

Recent research on mobile Internet protocol television and digital right management (DRM) interconnections has focused on multimedia technologies designed to enhance content scalability and adaptive content distribution. However, due to the architectural and scalable limitations, recent systems are not flexible and securable with respect to their adaptive content distribution and protective policy management. Therefore, we propose a content protective multi‐agent platform that provides secure multimedia services, correlation management, pattern‐based management, and multisource multi‐use (MsMu)‐based services. Our architecture, supported by DRM, lets us create a rich set of MsMu‐based content protection and seamless multimedia services through the extension of one source multi‐use (OsMu)‐based content services. We have verified our platform, which provides scalable and securable services with a 17% lower service response time by using a testbed.     

Service availability analysis in communication‐based train control systems using wireless local area networks

Data communication technology is one of the key subsystems in communication‐based train control (CBTC), which is an automated train control system for railways that ensures safe operation of rail vehicles using data communications. In CBTC systems, less service availability could cause train derailment, collision or even catastrophic loss of lives or assets. Therefore, the availability of data communication should be carefully considered in designing CBTC systems. In this paper, we propose two wireless local area network (WLAN)‐based data communication systems with redundancy in CBTC systems. The availability is analyzed using continuous time Markov chain (CTMC) model. We also model the WLAN‐based data communication system behavior with deterministic and stochastic Petri net (DSPN). The DSPN solution is used to show the soundness of our proposed CTMC model. Numerical examples illustrate that the proposed systems with redundancy can significantly improve service availability in CBTC systems. Copyright © 2012 John Wiley & Sons, Ltd.     

Fair end‐to‐end window‐based congestion control in time‐varying data communication networks

Communication networks are time varying and, hence, fair sharing of network resources among the users in such a dynamic environment is a challenging task. In this context, a time‐varying network model is designed, and the shortest user's route is found. In the designed network model, an end‐to‐end window‐based congestion control scheme is developed with the help of internal nodes or router, and the end user can get implicit feedback (throughput). This scheme is considered as fair if the allocation of resources among users minimizes overall congestion or backlog in the networks. Window update approach is based on a multi‐class fluid model and is updated dynamically by considering delays (communication, propagation, and queuing) and the backlog of packets in the user's routes. Convergence and stability of the window size are obtained using a Lyapunov function. A comparative study with other window‐based methods is also provided.     

U2RV: UAV‐assisted reactive routing protocol for VANETs

When it comes to keeping the data routing robust and effective in vehicular ad hoc networks (VANETs), stable and durable connectivity constitutes the keystone to ensure successful point‐to‐point communication. Since VANETs can comprise all kinds of mobile vehicles moving and changing direction frequently, this may result in frequent link failures and network partitions. Moreover, when VANETs are deployed in a city environment, another problem arises, that is, the existing obstructions (eg, buildings, trees, and hoppers) preventing the line‐of‐sight between vehicles, thus degrading wireless transmissions. Therefore, it is more complicated to design a routing technique that adapts to frequent changes in the topology. In order to settle all these problems, in this work, we design a flooding scheme that automatically reacts at each topology variation while overcoming the present obstacles while exchanging data in ad hoc mode with drones that are commonly called unmanned aerial vehicles (UAVs). Also, the aim of this work is to explore well‐regulated routing paths providing a long lifetime connectivity based on the amount of traffic and the expiration time of each discovered path. A set of experiments is carried out using a simulation, and the outcomes are confronted with similar protocols based on a couple of metrics. The results clearly show that the assistance of UAVs to vehicles is capable of providing high delivery ratios and low delivery delays while efficiently extending the network connectivity.     

Performance Analysis for MPEG‐4 Video Codec Based on On‐Chip Network

In this paper, we present a performance analysis for an MPEG‐4 video codec based on the on‐chip network communication architecture. The existing on‐chip buses of system‐on‐a‐chip (SoC) have some limitation on data traffic bandwidth since a large number of silicon IPs share the bus. An on‐chip network is introduced to solve the problem of on‐chip buses, in which the concept of a computer network is applied to the communication architecture of SoC. We compared the performance of the MPEG‐4 video codec based on the on‐chip network and Advanced Micro‐controller Bus Architecture (AMBA) on‐chip bus. Experimental results show that the performance of the MPEG‐4 video codec based on the on‐chip network is improved over 50% compared to the design based on a multi‐layer AMBA bus.     

Performance analysis of multi‐stage interference cancellation for ultra‐wide band multiple‐access communication systems

In this contribution, a novel particle swarm optimization (PSO)‐based multi‐user detector (MUD) aided time‐hopping ultra‐wide band (TH‐UWB) system has been investigated in the multi‐path channel model. In this approach, the PSO‐based MUD employs the output of the Rake receiver as its initial value to search for the best solution which results in a formulated optimization mechanism. By taking advantage of the heuristic values and the collective intelligence of PSO technique, the proposed detector offers almost the same bit error rate (BER) performance as the full‐search‐based optimum MUD does, while greatly reducing the potentially computational complexity. Simulation results have been provided to examine the evolutionary behavior and the detection performance of the proposed PSO‐based MUD in both the additive white Gaussian noise and the multi‐path fading channel. Copyright © 2011 John Wiley & Sons, Ltd.     

Energy‐aware virtual multi‐input‐multi‐output‐based routing for wireless ad hoc networks

Virtual multi‐input‐multi‐output (vMIMO) technology is becoming a promising way to improve the energy efficiency of wireless networks. Previous research always builds up the vMIMO‐based routing on the fixed structure such as clusters, and the MIMO mode is omitted in most cases. So, they cannot fully explore the advantage of vMIMO in routing. In this paper, we study a general routing scheme in which no fixed structure is required, and any communication mode of vMIMO is allowed for sake of the energy efficiency. We define two vMIMO‐based routing problems aiming to energy‐minimization and lifetime‐optimization. The first problem can be solved by our distributed energy‐minimum vMIMO‐based algorithm. The algorithm constructs the virtual cooperative graph, and applies the shortest path method on the virtual cooperative graph to solve this problem. The second problem is non‐deterministic polynomial‐time hard, and we design the distributed lifetime‐oriented vMIMO‐based algorithm, which is based on the modified Bellman‐Ford method. It can reach approximation ratio of four. The simulations show that our algorithms can work well in many situations. For example, distributed lifetime‐oriented vMIMO‐based algorithm can prolong the lifetime about 20.2% in dense topologies compared with the cooperative routing algorithm on average. Copyright © 2015 John Wiley & Sons, Ltd.     

SLLR‐MDIC: Spatial log‐likelihood multiuser detection and interference cancelation scheme for OFDM‐IDMA

Wireless communication systems have gained huge attraction from research community, industrial, and academic field due to their significant impact on improving the communication efficiency, ease of deployment, and cost‐effective solution for real‐time communication. In this field of wireless communication, cellular communications have grown rapidly due to their daily usages and advantages. This increased demand of cellular communication systems has led to the evolution of 3G, 4G, and 5G communication systems, which in turn demands for higher efficiency and better bandwidth utilization. Due to heavy usage of network communication, multiple users may cause interference which subsequently may lead to the performance degradation which could be addressed using multiuser detection scheme. However, several schemes have been introduced for improving the system performance, but multiple access (MA) still remains a challenging task. Hence, in this work, we present a novel approach called Spatial Log‐Likelihood Multiuser Detection and Interference Cancelation (SLLR‐MDIC) that uses interleaving division multiple access (IDMA) to improve the communication and developed a multiuser detection approach using spatial log‐likelihood ratios. Further, we have developed orthogonal frequency‐division multiple access (OFDM)–IDMA‐based interference cancelation scheme in multiple access to improve the performance using rake receiver based approach. The performance of SLLR‐MDIC scheme is compared with existing techniques of multiuser detection in terms of bit‐error rate (BER) and symbol error rate (SER). The experimental analysis shows that proposed approach achieves improved performance when compared with existing techniques.