Packet Transmission Delay Research Articles

A Joint Channel Selection and Routing Protocol for Cognitive Radio Network

In cognitive radio network, the activities of primary users will cause great influence on the stability of multiple hops routes between cognitive users. In this regard, a joint channel selection and routing protocol, termed as CSRP, is proposed to ensure route stability and reduce route latency between cognitive users. The channel availability based on historical information and the channel switching delay are used as the channel selection criteria to choose the end‐to‐end shortest route which possesses high data delivery probabilities and low delays. Besides, simulation results show that the proposed protocol has a better performance in terms of packet transmission delay and data delivery rate compared with the routing protocols based on delay (TDRP) and based on joint routing and channel allocation (PUB‐JRCA).

RARE: A Spectrum Aware Cross-Layer MAC Protocol for Cognitive Radio Ad-Hoc Networks

This paper proposes a spectRum Aware cRoss-layEr (RARE) medium access control protocol for cognitive radio ad-hoc networks. The RARE protocol initially splits the network into clusters, where cluster formation is defined as maximum edge biclique problem. Besides, in order to maintain the integrity of the cluster-based network, super-frame structure, and topology maintenance protocols are also presented in this paper. Moreover, RARE also integrates a delay-aware routing protocol, where the routing protocol is defined as a weighted graph problem. It is anticipated that clusters in RARE adapt themselves dynamically with respect to spectrum availability and nodes mobility. Furthermore, the routing protocol in RARE is expected to select stable paths while ensuring faster data delivery from a source node to the destination. Simulation is conducted to evaluate the performance of the proposed RARE protocol, where it is found that RARE outperforms existing approaches by maintaining a lesser number of clusters and a steady number of common channels. The simulation results also show that route selection in RARE proves to be more stable with the lowest packet transmission delay compared with the other approaches.

Improving Common Control Channel Capacity and Performance for Cognitive Radio Networks

Cognitive radio (CR) is a promising solution to cope with the inefficient usage of the frequency spectrum. CR lets its users leverage empty or idle parts of spectrum opportunistically. The medium access control (MAC) sub-layer in CR based networks is playing a crucial role in controlling user’s access to the shared medium and their interaction with Primary Users as well. Coordination and controlling users’ access to common control channel (CCC) at MAC sublayer can be a challenging issue in this type of networks. High availability of this channel is very important and crucial, so designing a mechanism which contributes to this, is of great importance. The CCC’s limited capacity alongside a large number of contending nodes for it causes channel saturation and consequently, leads to its unavailability. The paper introduces a useful method to compute supported saturation capacity of the CCC. It also introduces a new access mode for CCC called “Channelization”, to improve saturation capacity for it. The effect of “Channelization” scheme is also investigated on average packet delay, and according to it desirable parameters for channelization is calculated. Analytical analysis alongside simulation result shows that the channelization method can have a great impact on the increasing saturation capacity, and lower average packet transmission delay.

An algorithm for network and data-aware placement of multi-tier applications in cloud data centers

Today's Cloud applications are dominated by composite applications comprising multiple computing and data components with strong communication correlations among them. Although Cloud providers are deploying large number of computing and storage devices to address the ever increasing demand for computing and storage resources, network resource demands are emerging as one of the key areas of performance bottleneck. This paper addresses network-aware placement of virtual components (computing and data) of multi-tier applications in data centers and formally defines the placement as an optimization problem. The simultaneous placement of Virtual Machines and data blocks aims at reducing the network overhead of the data center network infrastructure. A greedy heuristic is proposed for the on-demand application components placement that localizes network traffic in the data center interconnect. Such optimization helps reducing communication overhead in upper layer network switches that will eventually reduce the overall traffic volume across the data center. This, in turn, will help reducing packet transmission delay, increasing network performance, and minimizing the energy consumption of network components. Experimental results demonstrate performance superiority of the proposed algorithm over other approaches where it outperforms the state-of-the-art network-aware application placement algorithm across all performance metrics by reducing the average network cost up to 67% and network usage at core switches up to 84%, as well as increasing the average number of application deployments up to 18%.

Performance analysis and saturation bound research of cyclic-quorum multichannel MAC protocol based on Markov chain model

In high diversity node situation, single-channel MAC protocols suffer from many collisions. To solve this problem, the research of multichannel MAC protocol has become a hotspot. And the cyclic quorum-based multichannel (CQM) MAC protocol outperformed others owing to its high frequency utilization. In addition, it can avoid the bottleneck that others suffered from and can be easily realized with only one transceiver. To obtain the accurate performance of CQM MAC protocol, a Markov chain model, which combines the channel hopping strategy of CQM protocol and IEEE 802.11 distributed coordination function (DCF), is proposed. The metrics (throughput and average packet transmission delay) are calculated in performance analysis, with respect to node number, packet rate, channel slot length and channel number. The results of numerical analysis show that the optimal performance of CQM protocol can be obtained in saturation bound situation. And then we obtain the saturation bound of CQM system by bird swarm algorithm (BSA). Finally, the Markov chain model and saturation bound are verified by Qualnet platform. And the simulation results show that the analytic and simulation results match very well.

A Hybrid Approach to Analyze the Impact of Vehicular Traffic on Performance of 802.11p Protocol for Safety Communications in Vehicular Ad Hoc Networks: A Quantitative Analysis

The rapid developments in wireless communications have introduced the vehicular ad hoc networks as an efficient tool to improve the safety of traffic through Dedicated Short Range Communications systems on highways. This paper addresses the broadcast mode of the 802.11p protocol and it quantitatively analyzes the impact of the highway vehicular traffic on its performance in terms of the packet delivery ratio and the packet transmission delay. To this aim, we propose to consider the number of the contending vehicles as a traffic-dependent stochastic counting process, which can be computed by analyzing the inter-vehicle spacing distribution in different traffic conditions. Based on the empirical data, the Lognormal and the Generalized Extreme Value distributions have been chosen to represent the inter-vehicle spacing distribution for a highway scenario in the semi-sparse and the intermediate traffic, respectively. The renewal theory is applied to the inter-vehicle spacing distribution to compute the traffic-dependent counting processes for each traffic condition. Through combination of the resulting counting processes with the performance analysis of the protocol, we propose a hybrid method that can be used to compute the upper bound, the lower bound, and the dominant bound and the probability of reaching to these bounds for desired performance metrics. As a result, the deviation of performance metrics from their average values is analyzed for each traffic condition. Our evaluations show that the accuracy of the proposed hybrid approach is consistent with the empirical results.

New results on filter design for sampled‐data systems with packet dropouts and transmission delays

In this study, the problem of H ∞ filtering for sampled-data systems under unreliable communication links is investigated. The phenomena of data packet dropouts and signal transmission delays are addressed in a unified framework. The objective is to design an admissible filter to guarantee the asymptotic stability of the filtering error system and minimise the H ∞ disturbance attenuation level. Thanks to the proposed novel Lyapunov–Krasovskii functional together with the improved Wirtinger's inequality and the reciprocally convex approach, novel sufficient linear-matrix-inequality-based conditions are obtained for the existence and design of admissible filters. Finally, two simulation examples are provided to illustrate the efficiency and less conservativeness of the proposed H ∞ filter design methods.

An intelligent scheduling scheme for real-time traffic management using Cooperative Game Theory and AHP-TOPSIS methods for next generation telecommunication networks

Abstract The emerging and exponential growth of telecommunication networks have developed a variety of smart and powerful devices to handle a wide range of multimedia applications such as Voice over IP (VoIP), video streaming, etc . 3GPP introduced Long Term Evolution (LTE) in release 8 and LTE-Advanced (A) in release 10 to support multimedia traffic as these technologies offers high data rate, high bandwidth, and low latency. It also created new challenges to handle resource allocation and power optimization of User Equipment (UE). The paper explores radio resource allocation and power consumption problem of UE in LTE environment. An intelligent scheduling scheme developed is based on Cooperative Game Theory (CGT) method and AHP-TOPSIS method. It distributes resources in a fair way among a number of applications and UE are prioritized based on certain criteria like delay, throughput history, UE buffer space and channel conditions and preferences. In LTE, Discontinuous Reception (DRX) has been adopted to conserve the battery life of UE. DRX periodically switches off the radio interfaces to conserve the battery life but it may breach Quality of Service (QoS). Therefore, the DRX parameters need to be further optimized to satisfy QoS and minimize power consumption of UE. DRX parameters are dynamically adjusted on the basis of current load and channel condition of the network. Power saving operations are numerically analyzed. Simulation results show that the expert and an intelligent system can distribute resources in a fair way among UE, improves the battery consumption of UE up to 85% and packets transmission delay by 10% as compared to existing scheme for real-time applications.

Practical Opportunistic Data Collection in Wireless Sensor Networks with Mobile Sinks

Wireless Sensor Networks with Mobile Sinks (WSN-MSs) are considered a viable alternative to the heavy cost of deployment of traditional wireless sensing infrastructures at scale. However, current state-of-the-art approaches perform poorly in practice due to their requirement of mobility prediction and specific assumptions on network topology. In this paper, we focus on low-delay and high-throughput opportunistic data collection in WSN-MSs with general network topologies and arbitrary numbers of mobile sinks. We first propose a novel routing metric, Contact-Aware ETX (CA-ETX), to estimate the packet transmission delay caused by both packet retransmissions and intermittent connectivity. By implementing CA-ETX in the defacto TinyOS routing standard CTP and the IETF IPv6 routing protocol RPL, we demonstrate that CA-ETX can work seamlessly with ETX. This means that current ETX-based routing protocols for static WSNs can be easily extended to WSN-MSs with minimal modification by using CA-ETX. Further, by combing CA-ETX with the dynamic backpressure routing, we present a throughput-optimal scheme Opportunistic Backpressure Collection (OBC). Both CA-ETX and OBC are lightweight, easy to implement, and require no mobility prediction. Through test-bed experiments and extensive simulations, we show that the proposed schemes significantly outperform current approaches in terms of packet transmission delay, communication overhead, storage overheads, reliability, and scalability.

A performance investigation on IoT enabled intra-vehicular wireless sensor networks

The concept of Internet of Things (IoT) can be utilised in vehicles, since the number of sensor nodes in vehicles is rising tremendously because of the uplifting demand of applications for security, safety and convenience. In order to establish the communication among these nodes inside a vehicle, a controller area network with wired architecture provides a prominent solution. However, this solution is not flexible because of the architectural complexity and the demand for a large number of sensors inside the vehicle; hence wired architectures are replaced by wireless ones. Moreover, scalability will be an important issue while introducing the IoT concept in Intra-Vehicular Wireless Sensor Networks (IVWSNs). In this paper, a comprehensive performance investigation on the IoT enabled IVWSNs (IoT-IVWSNs) to be carried out in order to address this issue. The overview of the IoT-IVWSNs with a comparative study of the existing technologies and the design challenges for such network are provided. The link design between an end-device and the control unit is analysed, and the performance of the network has been investigated and some open research issues are addressed. It reveals that the delay in packet transmission increases due to higher traffic loads and the number of end-devices. This result demonstrates that the existing MAC protocol works well for a small network (i.e., a network with a maximum number of 50 nodes) but is not suitable for a large network (i.e., a network with more than 50 nodes). The outcome of this research helps to design a smart car system.

Performance Analysis of IEEE 802.11p DCF for Multiplatooning Communications With Autonomous Vehicles

Platooning has been identified as a promising framework to improve road capacity, on-road safety, and energy efficiency. Enabling communications among vehicles in platoons is expected to enhance platoon control by keeping constant intervehicle and interplatoon distances. Characterizing the performance of intra- and interplatoon communications in terms of throughput and packet transmission delays is crucial for validating the effectiveness of information sharing on platoon control. In this paper, we introduce an IEEE 802.11p-based communication model for multiplatooning (a chain of platoons) scenarios. We present a probabilistic performance analysis of distributed-coordination-function-based intra- and interplatoon communications. Expressions for the transmission attempt probability, collision probability, packet delay, packet-dropping probability, and network throughput are derived. Numerical results show that the performance of interplatoon communications is affected by the transmissions of the first and last vehicles in a multiplatoon. This effect is reduced with an increase of the platoon number in the multiplatoon. In addition, the communication performance for three typical multiplatooning application scenarios is investigated, indicating that the IEEE 802.11p-based communication can support the timely delivery of vehicle information among platoons for diverse on-road applications.

Optimal Resource Allocation for Packet Delay Minimization in Multi-Layer UAV Networks

Research and development of heterogeneous small cell in cellular network accommodates the proliferation of data-hungry devices and applications. Meanwhile, for challenges in providing high-data-rate transmission in poor coverage area, utilizing unmanned aerial vehicles (UAVs) provides a promising solution attracting tremendous attention. However, tight integration of UAVs creates an obstruction in existing network to acquire high efficient resource utilization, which needs investigation in 3 D network architecture. In this letter, we propose a resource allocation optimization mechanism to minimize mean packet transmission delay in 3 D cellular network with multi-layer UAVs. Numerical results demonstrate effectiveness of the proposed algorithm, where optimal spectrum and power allocation can provide minimum packet transmission delay.

Hierarchical Route Optimization Scheme Using Advanced Binding Update List (BUL+) for Nested Mobile Networks

Supporting networks that roam as one unit is needed to provide the transparency of Internet in mobile frameworks, like cars, trains, planes, buses, etc. To accomplish this, NEMO (Network Mobility) Basic Support protocol has been proposed and developed by Internet Engineering Task Force (IETF). Although, it achieves continuous, optimal and secure communication to and from all nodes, it still suffers from many drawbacks, especially when the level of nesting increases. To overcome these limitations, this paper presents a new route optimization scheme for nested mobile network using hierarchical structure with Advanced Binding Update List (BUL+). From performance evaluation, it shows that this scheme reduces packet overhead, handoff latency, packet transmission delay, and achieves optimal routing. Keywords: Mobile IPv6, Network Mobility (NEMO), Nested mobile networks, Route Optimization

A Distributed Scheduling Algorithm for IEEE 802.15.4e Wireless Sensor Networks

As the widely adopted IEEE 802.15.4 standard exhibited severe drawbacks when used in multi-hop WSN environment, the IEEE Standards Association Board has released a revised version, IEEE 802.15.4e, which includes Time-Slotted Channel Hopping (TSCH) mechanism as the MAC amendment to IEEE 802.15.4. The key feature of IEEE 802.15.4e TSCH mechanism is to allow the sensors to plan the time-slot schedule for efficient data transmission. However, the standard does not specify how to plan a time-slot schedule so that data collected by the sensors can be received by the base station as soon as possible without being delayed by transmission conflicts. In this paper, we propose a constant-time, distributed time-slot scheduling algorithm to address this problem. Existing works on IEEE 802.15.4e TSCH scheduling depend on one or a few nodes to collect traffic-flow information from their descendants and plan a centralized time-slot schedule for the whole network. In contrast, our algorithm allows every sensor node to compute its time-slot schedule in a simple, truly distributed manner. Simulation results show that our algorithm significantly outperforms a state-of-the-art protocol in terms of the packet transmission delay and yields a smaller duty cycle.

Energy-Efficient Broadcasting Scheme for Smart Industrial Wireless Sensor Networks

In smart Industrial Wireless Sensor Networks (IWSNs), sensor nodes usually adopt a programmable technology. These smart devices can obtain new or special functions by reprogramming: they upgrade their soft systems through receiving new version of program codes. If sensor nodes need to be upgraded, the sink node will propagate program code packets to them through “one-to-many” broadcasting, and therefore new capabilities can be obtained, forming the so-called Software Defined Network (SDN). However, due to the high volume of code packet, the constraint energy of sensor node, and the unreliable link quality of wireless network, rapidly broadcasting the code packets to all nodes in network can be a challenge issue. In this paper, a novel Energy-efficient Broadcast scheme with adjustable broadcasting radius is proposed aiming to improve the performance of network upgrade. In our scheme, the nonhotspots sensor nodes take full advantage of their residual energy caused in data collection period to improve the packet reception probability and reduce the broadcasting delay of code packet transmission by enlarging the broadcasting radius, that is, the transmitting power. The theoretical analyses and experimental results show that, compared with previous work, our approach can averagely reduce the Network Upgrade Delay (NUD) by 14.8%–45.2% and simultaneously increase the reliability without harming the lifetime of network.

A QoS Enhancement Scheme through Joint Control of Clear Channel Assessment Threshold and Contending Window for IEEE 802.11e Broadcasting

In a WLAN, when a great many nodes coexist, the network may readily be congested, thus causing packets dropping and network performance degradation. To solve this issue, a lot of schemes have been proposed. However, most of the previous works attempt to avoid the possible channel congestion by controlling the packets generation rate and/or transmitting power of nodes, while the effects of Clear Channel Assessment (CCA) threshold are not well examined. In our paper, a Joint CCA threshold and contending window control algorithm (JCCA) is proposed to avoid channel congestion or reduce the congestion probability of broadcasting in an IEEE 802.11e network. Both the network conditions and the priorities of messages are taken into account to improve the broadcasting performance in our paper. According to the simulation results, it can be concluded that our scheme can significantly increase the network throughput as well as packets delivery ratio and reduce the packet transmission delay compared to the IEEE 802.11e and Adaptive Carrier Sensing-Based MAC Designs (ACSBM) protocol.

Intermittent geocast routing in urban vehicular delay tolerant networks

Nowadays, both vehicular active safety service and user infotainment service have become two core applications for urban Vehicular Delay Tolerant Networks (uVDTNs). Both core applications require a high data transmission capacity over uVDTNs. In addition, the connection between any two vehicles in uVDTNs is intermittent and opportunistic. Intermittent data dissemination over uVDTNs is a stringent and challenging issue. In this paper, we propose Intermittent Geocast Routing (IGR). For the first step, IGR has to estimate the active connection time interval via the moving directions and velocities between any two vehicles. Second, the throughput function for uVDTNs is fitted by building a wavelet neural network traffic model. Third, the throughput function within the effective connection time interval is integrated to obtain the forwarding capability estimation of the node. Fourth, a high-efficiency geocast routing algorithm using the node forwarding capability for uVDTNs is designed. Finally, IGR is simulated on the opportunistic Network Environment simulator. Experimental results show that IGR can greatly improve the packet delivery ratio, transmission delay, delay jitter, and packet loss rate compared with the state of the art.

Wireless Energy and Information Transmission Using Feedback: Infinite and Finite Block-Length Analysis

In this paper, we propose and analyze a wireless energy and information transfer system. To reduce the outage probability, compared with open-loop communication, we implement retransmission protocols both in the energy and in the information transmission phases. We use some recent results on finite block-length codes to analyze the effect of the energy and information signals lengths on the system outage probability/throughput. Finally, under a packet transmission delay constraint, we derive the optimal power allocation and time sharing between the energy and information signals, such that the energy-constrained outage probability is minimized. The simulation and analytical results demonstrate that the retransmission-based protocols are efficient techniques to reduce the energy-limited outage probability of wireless energy and information transmission systems.

Energy Efficient Wireless Sensor Networks using Dual Cluster Head with Sleep/Active Mechanism

Objectives: In wireless sensor networks, high energy consumption occurs when the generated data is transmitted to the base station. This high energy consumption affects the longevity of the network. In a wireless sensor network, the energy of sensor nodes is a scarce resource. To extend the lifetime of wireless sensor network, it is essential to reduce the energy consumption. Methods/Statistical Analysis: In the proposed work, the classical LEACH protocol clustering algorithm is enhanced with sleep/active schedule and a new algorithm namely ESDCH (Energy Saving Dual-Cluster Head) protocol is proposed to prolong the network lifetime. In the proposed ESDCH method, the sensor nodes are organized into clusters. The sensor nodes in each cluster set their states into sleep/active mode based on their residual energies. In lieu of selecting a single cluster-head, our protocol selects two cluster heads in each cluster based on their residual energies. Firstly, a Primary-CH is chosen which is having the highest energy level, and a Secondary-CH is chosen from the remaining nodes which is having energy level next to Primary-CH and also closer to the Primary-CH. Because of wireless transmission capability, Primary-CH is able to receive data from other sensor nodes. Using multi-hop communication, every Primary-CH can aggregate data within each cluster and send the aggregated data to the base station. The Secondary-CH assumes the role of CH whenever the Primary-CH fails in its purpose. The entire simulations are carried out using MATLAB environment. Findings: The performance results obtained using ESDCH and the LEACH protocols are matched and the superiority of ESDCH performance is evaluated. From the simulation results, we show that the proposed protocol marginally reduces the total energy consumption in the network. Also, the simulation results show that the number of live nodes in the network is increased, packet transmission delay reduced and packet delivery rate increased in the proposed method. Application/ Improvement: In the newly introduced dual cluster head protocol, it would be shown that the energy consumed is much less and hence the network’s lifetime is increased.

A QOS Parameter based Solution for Black hole Denial of Service Attack in Wireless Sensor Networks

Background/Objectives: A typical Wireless Sensor Network (WSN) is a collection of Sensor nodes with limited charge that get deployed in a range enabling different applications. Enormous potential is there for deployment of WSN in consumer centric applications, industry sector and defence. Method: WSNs are vulnerable to various types of attack, upon which black-hole, a type of Denial of Service (DoS) pose enormous challenge in detection and defence. The primary characteristic of the attack is that reprogramming done by attackers in the captured nodes block the packets received than forwarding to the base station. This results in information entering the black hole area not getting routed to the destination and degradation of QoS factors of delay and final throughput. In this study a comparative performance weighing of Star and tree topology setup of WSN nodes is carried out under the black hole scenario. In case, the parameter of delay is vital Mesh setup is chosen and in the requirement of throughput efficiency and fault tolerance Star topology is chosen. A methodology for choosing the topology depending on the required service parameter under black hole scenario is also devised. Findings: The vital parameters considered for the simulation study are delay in transmission of packets and throughput efficiency among the sensor nodes. The results prove a considerable reduction of the parameter of delay in transmission of packets if hybrid topology is followed and a reasonable increase in the QoS parameter of throughput as mesh topology is adopted during transmission in a black hole vulnerable network. Improvements: The vital parameters of negligible delay and throughput efficiency that contribute effective cooperation among the sensor nodes are taken into account while choosing the appropriate topology, and the results show the distribution of the parameter values for the particular topology chosen.