A Utility-Based Buffer Management Policy for Improving Data Dissemination in Opportunistic Networks

In opportunistic networks, most existing buffer management policies including scheduling and passive dropping policies are mainly for routing protocols. In this paper, we proposed a Utility-based Buffer Management strategy(UBM) for data dissemination in opportunistic networks. In UBM, we first design a method of computing the utility values of caching messages according to the interest of nodes and the delivery probability of messages, and then propose an overall buffer management policy based on the utility. UBM driven by receivers completely implements not only caching policies, passive and proactive dropping policies, but also scheduling policies of senders. Simulation results show that, compared with some classical dropping strategies, UBM can obtain higher delivery ratio and lower delay latency by using smaller network cost.

Safe Navigation for UAV-Enabled Data Dissemination by Deep Reinforcement Learning in Unknown Environments

Unmanned aerial vehicles(UAVs) are increasingly considered in safe autonomous navigation systems to explore unknown environments where UAVs are equipped with multiple sensors to perceive the surroundings. However, how to achieve UAVenabled data dissemination and also ensure safe navigation synchronously is a new challenge. In this paper, our goal is minimizing the whole weighted sum of the UAV’s task completion time while satisfying the data transmission task requirement and the UAV’s feasible flight region constraints. However, it is unable to be solved via standard optimization methods mainly on account of lacking a tractable and accurate system model in practice. To overcome this tough issue,we propose a new solution approach by utilizing the most advanced dueling double deep Q network(dueling DDQN) with multi-step learning. Specifically, to improve the algorithm, the extra labels are added to the primitive states. Simulation results indicate the validity and performance superiority of the proposed algorithm under different data thresholds compared with two other benchmarks.

Hash-area-based data dissemination protocol in wireless sensor networks

HashQuery,a Hash-area-based data dissemination protocol,was designed in wireless sensor networks. Using a Hash function which uses time as the key,both mobile sinks and sensors can determine the same Hash area. The sensors can send the information about the events that they monitor to the Hash area and the mobile sinks need only to query that area instead of flooding among the whole network,and thus much energy can be saved. In addition,the location of the Hash area changes over time so as to balance the energy consumption in the whole network. Theoretical analysis shows that the proposed protocol can be energy-efficient and simulation studies further show that when there are 5 sources and 5 sinks in the network,it can save at least 50% energy compared with the existing two-tier data dissemination(TTDD) protocol,especially in large-scale wireless sensor networks.

Real traffic-data based evaluation of vehicular traffic environment and state- of-the-art with future issues in location-centric data dissemination for VANETs

Extensive investigation has been performed in location-centric or geocast routing protocols for reliable and efficient dissemination of information in Vehicular Adhoc Networks （VANETs）. Various location-centric routing protocols have been suggested in literature for road safety ITS applications considering urban and highway traffic environment. This paper characterizes vehicular environments based on real traffic data and investigates the evolution of location-centric data dissemination. The current study is carded out with three main objectives： （i） to analyze the impact of dynamic traffic environment on the design of data dissemination techniques, （ii） to characterize location-centric data dissemination in terms of functional and qualitative behavior of protocols, properties, and strengths and weaknesses, and （iii） to find some future research directions in information dissemination based on location. Vehicular traffic environments have been classified into three categories based on physical characteristics such as speed, inter-vehicular distance, neighborhood stability, traffic volume, etc. Real traffic data is considered to analyze on-road traffic environments based on the measurement of physical parameters and weather conditions. Design issues are identified in incorporating physical parameters and weather conditions into data dissemination. Functional and qualitative characteristics of location-centric techniques are explored considering urban and highway environments. Comparative analysis of location-centric techniques is carded out for both urban and highway environments individually based on some unique and common characteristics of the environments. Finally, some future research directions are identified in the area based on the detailed investigation of traffic environments and location-centric data dissemination techniques.

Reliable connectivity and efficient data dissemination in VANETs

Connectivity and data dissemination in vehicular ad hoc networks(VANETs)have recently received considerable attention.Due to the unique characteristics of VANETs,the network connectivity is poor and reliable transmission in VANETs is hard to achieve.In this paper,we analyze the connectivity of randomly deployed vehicles on a road in VANETs and show the relation among the connectivity,the vehicle density and the communication radius.The reliable data dissemination scheme based on assisted nodes is studied.The simulation results show our novel scheme increases the network performance in terms of data dissemination rate.

On Peer-Assisted Data Dissemination in Data Center Networks: Analysis and Implementation

Data Center Networks （DCNs） are the fundamental infrastructure for cloud computing. Driven by the massive parallel computing tasks in cloud computing, one-to-many data dissemination becomes one of the most important traffic patterns in DCNs. Many architectures and protocols are proposed to meet this demand. However, these proposals either require complicated configurations on switches and servers, or cannot deliver an optimal performance. In this paper, we propose the peer-assisted data dissemination for DCNs. This approach utilizes the rich physical connections with high bandwidths and mutli-path connections, to facilitate efficient one-to-many data dissemination. We prove that an optimal P2P data dissemination schedule exists for FatTree, a specially- designed DCN architecture. We then present a theoretical analysis of this algorithm in the general multi-rooted tree topology, a widely-used DCN architecture. Additionally, we explore the performance of an intuitive line structure for data dissemination. Our analysis and experimental results prove that this simple structure is able to produce a comparable performance to the optimal algorithm. Since DCN applications heavily rely on virtualization to achieve optimal resource sharing, we present a general implementation method for the proposed algorithms, which aims to mitigate the impact of the potentially-high churn rate of the virtual machines.

A Survey on Data Dissemination in Wireless Sensor Networks

Wireless sensor networks （WSNs） have been applied in a variety of application areas. Most WSN systems, once deployed, are intended to operate unattended for a long period. During the lifetime, it is necessary to fix bugs, reconfigure system parameters, and upgrade the software in order to achieve reliable system performance. However, manually collecting all nodes back and reconfiguring through serial connections with computer is infeasible since it is labor-intensive and inconvenient due to the harsh deploying environments. Hence, data dissemination over multi-hop is desired to facilitate such tasks. This survey discusses the requirements and challenges of data dissemination in WSNs, reviews existing work, introduces some relevant techniques, presents the metrics of the performance and comparisons of the state-of-the-art work, and finally suggests the possible future directions in data dissemination studies. This survey elaborates and compares existing approaches of two categories： structure-less schemes and structure-based schemes, classified by whether or not the network structure information is used during the disseminating process. In existing literatures, different categories have definite boundary and limited analysis on the trade-off between different categories. Besides, there is no survey that discusses the emerging techniques such as Constructive Interference （CI） while these techniques have the chance to change the framework of data dissemination. In a word, even though many efforts have been made, data dissemination in WSNs still needs some more work to embrace the new techniques and improve the efficiency and practicability further.

Data dissemination model using Epidemic and Transmission-Segment-based Geographic Routing protocol:a new perspective in vehicular ad hoc networks

Purpose-The purpose of this paper is to introduce a new data dissemination model in order to improve the performance of transmission in VANET.It proposes a protocol named Epidemic and Transmission-Segmentbased Geographic Routing(ETSGR)and outlining the issues due to high mobility of nodes and uncertain physical topologies in the network.The proposed ETSGR is mainly used to analyze the vehicle state,direction,distance,traffic density and link quality of the network.Design/methodology/approach-This research work based on ETSGR protocol mainly uses epidemic algorithmin order to find the vehicle state based on susceptible,infected and recovered(SIR)model.Furthermore,the vehicle position and finding the head node in the network is utilized using the transmission segment protocol based on geographic routing and analyses each node to formthe segments and find the destination to transmit the data in timely manner.Findings-The paper provides the enhancement of the performance based on some metrics such as end-to-end delaythat obtained 0.62%,data throughput as 32.3%,packetdelivery ratio as 67%and one-hop communicationas 13%.The proposed ETSGR protocolanalyzes the state of the vehiclecorrectly and each node segmented to transmit the data with the timely manner and obtaining reliable performanceeven with highmobility of nodes in the network.Research limitations/implications-The proposed ETSGR protocol may have some limitation when considering the timing which should improve even in increasing many number of vehicles and different road segments.Practical implications-This paper includes some suggestions for the practical deployment of the approach in which a real-time traffic analysis can be evaluated for taking prior actions during an emergency situation and proper dissemination of data in timely manner can help utilize the guidance of proper planning of roads.Originality/value-This research fulfills an enhanced protocol to improve the performance of data dissemination.

COCP:Coupling Parameters Content Placement Strategy for In-Network Caching-Based Content-Centric Networking

On-path caching is the prominent module in Content-Centric Networking(CCN),equipped with the capability to handle the demands of future networks such as the Internet of Things(IoT)and vehicular networks.The main focus of the CCN caching module is data dissemination within the network.Most of the existing strategies of in-network caching in CCN store the content at the maximumnumber of routers along the downloading path.Consequently,content redundancy in the network increases significantly,whereas the cache hit ratio and network performance decrease due to the unnecessary utilization of limited cache storage.Moreover,content redundancy adversely affects the cache resources,hit ratio,latency,bandwidth utilization,and server load.We proposed an in-network caching placement strategy named Coupling Parameters to Optimize Content Placement(COCP)to address the content redundancy and associated problems.The novelty of the technique lies in its capability tominimize content redundancy by creating a balanced cache space along the routing path by considering request rate,distance,and available cache space.The proposed approach minimizes the content redundancy and content dissemination within the network by using appropriate locations while increasing the cache hit ratio and network performance.The COCP is implemented in the simulator(Icarus)to evaluate its performance in terms of the cache hit ratio,path stretch,latency,and link load.Extensive experiments have been conducted to evaluate the proposed COCP strategy.The proposed COCP technique has been compared with the existing state-of-theart techniques,namely,Leave Copy Everywhere(LCE),Leave Copy Down(LCD),ProbCache,Cache Less forMore(CL4M),and opt-Cache.The results obtained with different cache sizes and popularities show that our proposed caching strategy can achieve up to 91.46%more cache hits,19.71%reduced latency,35.43%improved path stretch and 38.14%decreased link load.These results confirm that the proposed COCP strategy has the potential capability to handle the demands of future networks such as the Internet of Things(IoT)and vehicular networks.

acSB:Anti-Collision Selective-Based Broadcast Protocol in CRAdHocs

As a fundamental operation in ad hoc networks,broadcast could achieve efficient message propagations.Particularl y in the cognitive radio ad hoc network where unlicensed users have different sets of available channels,broadcasts are carried out on multiple channels.Accordingly,channel selection and collision avoidance are challenging issues to balance the efficiency against the reliability of broadcasting.In this paper,an anticollision selective broadcast protocol,called acSB,is proposed.A channel selection algorithm based on limited neighbor information is considered to maximize success rates of transmissions once the sender and receiver have the same channel.Moreover,an anticollision scheme is adopted to avoid simultaneous rebroadcasts.Consequently,the proposed broadcast acSB outperforms other approaches in terms of smaller transmission delay,higher message reach rate and fewer broadcast collisions evaluated by simulations under different scenarios.

Redundant Transmission Control Algorithm for Information-Centric Vehicular IoT Networks

Vehicular Adhoc Networks(VANETs)enable vehicles to act as mobile nodes that can fetch,share,and disseminate information about vehicle safety,emergency events,warning messages,and passenger infotainment.However,the continuous dissemination of information fromvehicles and their one-hop neighbor nodes,Road Side Units(RSUs),and VANET infrastructures can lead to performance degradation of VANETs in the existing hostcentric IP-based network.Therefore,Information Centric Networks(ICN)are being explored as an alternative architecture for vehicular communication to achieve robust content distribution in highly mobile,dynamic,and errorprone domains.In ICN-based Vehicular-IoT networks,consumer mobility is implicitly supported,but producer mobility may result in redundant data transmission and caching inefficiency at intermediate vehicular nodes.This paper proposes an efficient redundant transmission control algorithm based on network coding to reduce data redundancy and accelerate the efficiency of information dissemination.The proposed protocol,called Network Cording Multiple Solutions Scheduling(NCMSS),is receiver-driven collaborative scheduling between requesters and information sources that uses a global parameter expectation deadline to effectively manage the transmission of encoded data packets and control the selection of information sources.Experimental results for the proposed NCMSS protocol is demonstrated to analyze the performance of ICN-vehicular-IoT networks in terms of caching,data retrieval delay,and end-to-end application throughput.The end-to-end throughput in proposed NCMSS is 22%higher(for 1024 byte data)than existing solutions whereas delay in NCMSS is reduced by 5%in comparison with existing solutions.

Novel Technique in Multihop Environment for Efficient Emergency Message Dissemination and Lossless Video Transmission in VANETS

Vehicular ad hoc networks(VANETs)support safety-and non-safety-related applications that require the transmission of emergency safety messages and periodic beacon messages.The dedicated short-range communication(DSRC)standard in VANETs is used to exchange safety messages,and is involved in multi-hop data dissemination and routing.Many researchers have focused either on emergency data dissemination or routing,but both are critical.Routing protocols are commonly used for position-based routing and distancebased routing.This paper focuses on both emergency data dissemination and multi-hop routing,with the selection of the best data disseminator and trustworthy forwarder.To select the best forwarder,ring partitioning is performed,which segregates vehicles into rings based on the coverage area for routing.Each partition is selected with a best forwarder,which minimizes the hop count for data transmission.The work also includes effective video transmission for a user’s request.Video transmission in VANETs is involved in this work to provide efficient video delivery between rapidly travelling vehicles with reduced delay owing to the selection of good-quality channels.Video transmission is prioritized according to frame types,and they are then transmitted with respect to the preference of channels.The major issue in video streaming is the loss of packets,which is our focus to minimize it.Our proposed VANET environment is simulated in OMNeT++,and the results show remarkable improvements in terms of the packet delivery ratio,end-to-end delay,and reliability.

NBgossip:An Energy-Efficient Gossip Algorithm for Wireless Sensor Networks

Gossip-based algorithms for information dissemination have recently received significant attention for sensor and ad hoc network applications because of their simplicity and robustness. However, a common drawback of many gossip-based protocols is the waste of energy in passing redundant information over the network. Thus gossip algorithms need to be re-engineered in order to become applicable to energy constrained networks. In this paper, we consider a scenario where each node in the network holds a piece of information （message） at the beginning, and the objective is to simultaneously disseminate all information （messages） among all nodes quickly and cheaply. To provide a practical solution to this problem for ad hoc and sensor networks, NBgossip algorithm is proposed, which is based on network coding and neighborhood gossip. In NBgossip, nodes do not simply forward messages they receive, instead, the linear combinations of the messages are sent out. In addition, every node exchanges messages with its neighboring nodes only. Mathematical proof and simulation studies show that the proposed NBgossip terminates in the optimal O（n）-order rounds and outperforms the existing gossip-based approaches in terms of energy consumption incurred in spreading all the information.