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

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Chen Chen ◽  
Honghui Zhao ◽  
Hongyu Xiang ◽  
Canding Sun ◽  
Jisheng Sui ◽  
...  
Keyword(s):  
Control Algorithm ◽  
Network Performance ◽  
Packet Transmission ◽  
Ieee 802.11E ◽  
Joint Control ◽  
Delivery Ratio ◽  
Clear Channel Assessment ◽  
Carrier Sensing ◽  
Simulation Results ◽  
Clear Channel

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.

scholarly journals Energy-Efficient Check-and-Spray Geocast Routing Protocol for Opportunistic Networks

Information ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 504
Author(s):  
Khuram Khalid ◽  
Isaac Woungang ◽  
Sanjay Kumar Dhurandher ◽  
Jagdeep Singh ◽  
Joel J. P. C. Rodrigues
Keyword(s):  
Routing Protocol ◽  
Energy Efficient ◽  
Network Performance ◽  
Opportunistic Networks ◽  
Packet Transmission ◽  
Superior Performance ◽  
Delivery Ratio ◽  
Node Mobility ◽  
Mobile Nodes ◽  
Hop Count

Opportunistic networks (OppNets) are a type of challenged network where there is no guaranteed of end-to-path between the nodes for data delivery because of intermittent connectivity, node mobility and frequent topology changes. In such an environment, the routing of data is a challenge since the battery power of the mobile nodes drains out quickly because of multi-routing activities such as scanning, transmitting, receiving, and computational processing, effecting the overall network performance. In this paper, a novel routing protocol for OppNets called Energy-Efficient Check-and-Spray Geocast Routing (EECSG) is proposed, which introduces an effective way of message distribution in the geocasting region to all residing nodes while saving the energy consumption by restricting the unnecessary packet transmission in that region. A Check-and-Spray technique is also introduced to eliminate the overhead of packets in the geocast region. The proposed EECSG is evaluated by simulations and compared against the Efficient and Flexible Geocasting for Opportunistic Networks (GSAF) and the Centrality- Based Geocasting for Opportunistic networks (CGOPP) routing protocols in terms of average latency, delivery ratio, number of messages forwarded, number of dead nodes, overhead ratio, and hop count, showing superior performance.

scholarly journals Performance of Non-Uniform Duty-Cycled ContikiMAC in Wireless Sensor Networks

2017 ◽  
Vol 7 (2) ◽  
pp. 942
Author(s):  
Nur Rabiul Liyana Mohamed ◽  
Ansar Jamil ◽  
Lukman Hanif Audah Audah ◽  
Jiwa Abdullah ◽  
Rozlan Alias
Keyword(s):  
Duty Cycle ◽  
Dynamic Network ◽  
Poor Performance ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Sleep Mode ◽  
Bursty Traffic ◽  
Delivery Ratio ◽  
Clear Channel Assessment ◽  
Clear Channel

<span lang="EN-GB">Wireless Sensor Network (WSN) is a promising technology in Internet of Things (IoTs) because it can be implemented in many applications. However, a main drawback of WSN is it has limited energy because each sensor node is powered using batteries. Therefore, duty-cycle mechanisms are introduced to reduce power consumption of the sensor nodes by ensuring the sensor nodes in the sleep mode almost of the time in order to prolong the network lifetime. One of the de-facto standard of duty-cycle mechanism in WSN is ContikiMAC, which is the default duty-cycle mechanism in Contiki OS. ContikiMAC ensures nodes can participate in network communication yet keep it in sleep mode for roughly 99\% of the time. However, it is found that the ContikiMAC does not perform well in dynamic network conditions. In a bursty network, ContikiMAC provides a poor performance in term of packet delivery ratio, which is caused by congestion. One possible solution is ContikiMAC should increase its duty-cycle rate in order to support the bursty traffic. This solution creates a non-uniform duty-cycle rates among the sensor nodes in the network. This work aims to investigate the effect of non-uniform duty-cycle rates on the performance on ContikiMAC. Cooja simulator is selected as the simulation tool. Three different simulation scenarios are considered depending on the Clear Channel Assessment Rate (CCR) configurations: a low uniform CCR value (Low-CCR), a high uniform CCR value (High-CCR) and non-uniform CCR values (Non-uniform-CCR). The simulation results show that the Low-CCR scenario provides the worst performance of PDR. On the other hand, the High-CCR scenario provides the best performance of PDR. The Non-uniform-CCR provides PDR in between of Low-CCR and High-CCR.</span>

scholarly journals Sinkhole Attack Detection and Prevention using Agent Based Algorithm

2021 ◽  
Vol 23 (05) ◽  
pp. 526-544
Author(s):  
Ashwini V. Jatti ◽  
◽  
Dr V. J. K. Kishor Sonti ◽  
Keyword(s):  
Network Performance ◽  
Attack Detection ◽  
Packet Delivery Ratio ◽  
Delivery Ratio ◽  
Agent Based ◽  
Data Packets ◽  
Packet Delivery ◽  
Jitter Delay ◽  
Network Simulations ◽  
Simulation Results

This study presents sinkhole attack detection and prevention using agent-based algorithm. In this algorithm, agents are used to provide information to all node from its reliable neighbors by negotiation in three steps, thus nodes may not be able to pay the attention to the traffic made by sinkhole attacker. In this work, network scale of 500×500 m2 square areas have been considered. Series of simulation are carried in each experiment. Every simulation run is being organized to work for 10mins. Network performance is evaluated in terms of throughput, packet delivery ratio, jitter, delay in packets delivery, data packets received, data packets drop using network simulations software. Network simulation results depicts that in proposed algorithm, throughput increases by 15 to 20 percent, packet delivery ratio increases by 30 to 40%, decrease in the jitter by 10 to 15 %, delay in packets delivery is decreased by 15 to 20 %, data packets received are increased by 15 to 20 % and number of the data packets drop are decreased by 5 to 15 %. Based on simulation results throughput, packet delivery ratio and data packets received increased in proposed agent-based algorithm. However, it is observed that, jitter, delay in packets delivery and data packets drop were decreased.

scholarly journals Metric Routing Protocol for Detecting Untrustworthy Nodes for Packet Transmission

2021 ◽  
Vol 3 (2) ◽  
pp. 67-76
Author(s):  
Smys S ◽  
Vijesh Joe
Keyword(s):  
Game Theory ◽  
Routing Protocol ◽  
Packet Transmission ◽  
Delivery Ratio ◽  
Trust Evaluation ◽  
Power Networks ◽  
Lossy Networks ◽  
Packet Delivery ◽  
Evolutionary Simulation ◽  
Simulation Results

IoT objects that have a resource constrained nature resulting in a number of attacks in the routing protocol for lossy networks and low-power networks. RPL is very vulnerable to selfish behaviours and internal attacks though they are built with encryption protection to secure messages. To address this vulnerability, in this paper, we propose a novel trustworthiness methodology based on metric for incorporating trust evaluation, enhancing the robustness of security mechanism. Simulation results indicate that the proposed work is efficient in terms of throughput, nodes’ rank changes, energy consumption and packet delivery ratio. Moreover, using mathematical modelling, it has been observed that this methodology meets the demands of loop-freeness, optimality and consistency. This shows that this metic has both monotonicity and isotonicity requirements to enable the routing protocol. Incorporating the concepts of game theory, we can use this technique as a strategy to iterate Prisoner’s Dilemma. Both evolutionary simulation and mathematical analysis indicate that the proposed metric-based routing protocol is an efficient technique in promoting evolution and stability of the IoT network.

scholarly journals A Dataset to Evaluate IEEE 802.15.4g SUN for Dependable Low-Power Wireless Communications in Industrial Scenarios

Data ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 64 ◽  
Author(s):  
Pere Tuset-Peiró ◽  
Ruan D. Gomes ◽  
Pascal Thubert ◽  
Eva Cuerva ◽  
Eduard Egusquiza ◽  
...  
Keyword(s):  
Task Force ◽  
Industrial Applications ◽  
Delivery Ratio ◽  
Sensitivity Limit ◽  
Received Signal Strength Indicator ◽  
External Interference ◽  
Packet Delivery ◽  
Clear Channel Assessment ◽  
Utility Network ◽  
Clear Channel

This article presents a dataset obtained from the deployment of an IEEE 802.15.4g SUN (Smart Utility Network) single-hop network (11 nodes) in a large industrial scenario (110,044 m 2 ) for a long period of time (99 days). The dataset contains ∼11 M entries with RSSI (Received Signal Strength Indicator), CCA (Clear Channel Assessment), and PDR (Packet Delivery Ratio) values. The analyzed results show a high variability in the average RSSI (i.e., between −82.1 dBm and −101.7 dBm) and CCA (i.e., between −111.2 dBm and −119.9 dBm) values, which is caused by the effects of multi-path propagation and external interference. Despite being above the sensitivity limit for each modulation, these values result in poor average PDR values (i.e., from 65.9% to 87.4%), indicating that additional schemes are needed to meet the link reliability requirements of industrial applications. Hence, the presented dataset will allow researchers and practitioners to propose novel mechanisms and evaluate their performance using realistic conditions, enabling the dependability vision of the RAW (Reliable and Available Wireless) WG (Working Group) at the IETF (Internet Engineering Task Force).

scholarly journals Node-Dependence-Based Dynamic Incentive Algorithm in Opportunistic Networks

2014 ◽  
Vol 2014 ◽  
pp. 1-14
Author(s):  
Ruiyun Yu ◽  
Pengfei Wang
Keyword(s):  
Network Performance ◽  
Opportunistic Networks ◽  
Delivery Ratio ◽  
Selfish Nodes ◽  
Performance Incentive ◽  
Average Latency ◽  
Simulation Results ◽  
End To End ◽  
Reliability And Robustness ◽  
Reward And Punishment

Opportunistic networks lack end-to-end paths between source nodes and destination nodes, so the communications are mainly carried out by the “store-carry-forward” strategy. Selfish behaviors of rejecting packet relay requests will severely worsen the network performance. Incentive is an efficient way to reduce selfish behaviors and hence improves the reliability and robustness of the networks. In this paper, we propose the node-dependence-based dynamic gaming incentive (NDI) algorithm, which exploits the dynamic repeated gaming to motivate nodes relaying packets for other nodes. The NDI algorithm presents a mechanism of tolerating selfish behaviors of nodes. Reward and punishment methods are also designed based on the node dependence degree. Simulation results show that the NDI algorithm is effective in increasing the delivery ratio and decreasing average latency when there are a lot of selfish nodes in the opportunistic networks.

scholarly journals MedShard: Electronic Health Record Sharing Using Blockchain Sharding

2021 ◽  
Vol 13 (11) ◽  
pp. 5889
Author(s):  
Faiza Hashim ◽  
Khaled Shuaib ◽  
Farag Sallabi
Keyword(s):  
Healthcare System ◽  
Small Groups ◽  
Network Performance ◽  
Communication Overhead ◽  
Privacy And Security ◽  
Health Records ◽  
Medical Practitioners ◽  
Blockchain Technology ◽  
Simulation Results ◽  
Electronic Health

Electronic health records (EHRs) are important assets of the healthcare system and should be shared among medical practitioners to improve the accuracy and efficiency of diagnosis. Blockchain technology has been investigated and adopted in healthcare as a solution for EHR sharing while preserving privacy and security. Blockchain can revolutionize the healthcare system by providing a decentralized, distributed, immutable, and secure architecture. However, scalability has always been a bottleneck in blockchain networks due to the consensus mechanism and ledger replication to all network participants. Sharding helps address this issue by artificially partitioning the network into small groups termed shards and processing transactions parallelly while running consensus within each shard with a subset of blockchain nodes. Although this technique helps resolve issues related to scalability, cross-shard communication overhead can degrade network performance. This study proposes a transaction-based sharding technique wherein shards are formed on the basis of a patient’s previously visited health entities. Simulation results show that the proposed technique outperforms standard-based healthcare blockchain techniques in terms of the number of appointments processed, consensus latency, and throughput. The proposed technique eliminates cross-shard communication by forming complete shards based on “the need to participate” nodes per patient.

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