Search results for "Packet loss"
showing 10 items of 24 documents
Impact of Spreading Factor Imperfect Orthogonality in LoRa Communications
2017
In this paper we study the impact of imperfect-orthogonality in LoRa spreading factors (SFs) in simulation and real-world experiments. First, we analyze LoRa modulation numerically and show that collisions between packets of different SFs can indeed cause packet loss if the interference power received is strong enough. Second, we validate such findings using commercial devices, confirming our numerical results. Third, we modified and extended LoRaSim, an open-source LoRa simulator, to measure the impact of inter-SF collisions and fading (which was not taken into account previously in the simulator). Our results show that non-orthogonality of the SFs can deteriorate significantly the perform…
Does higher datarate perform better in IEEE 802.11-based multihop ad hoc networks?
2007
Due to the nature that high datarate leads to shorter transmission range, the performance enhancement by high datarate 802.11 WLANs may be degraded when applying high datarate to an 802.11 based multihop ad hoc network. In this paper, we evaluate, through extensive simulations, the performance of multihop ad hoc networks at multiple transmission datarates, in terms of the number of hops between source and destination, throughput, end-to-end delay and packet loss. The study is conducted based on both stationary chain topology and mesh topologies with or without node mobility. From numerical results on network performance based on chain topology, we conclude that there is almost no benefit by…
Testing the H.264 error-resilience on wireless ad-hoc networks
2004
The purpose of this paper is to provide a framework to tune and evaluate the performance of the H.264 codec in 802.11b wireless ad-hoc networks. The codec's error-resilience features are measured under stress conditions typical to these networks, and the most critical parameters are presented. We present solutions concerning the random packet loss problem and show how to quickly recover from packet loss bursts.
Performance of H.264 compressed video streams over 802.11b based MANETs
2004
We address the problem of video streams transmission in 802.11b based mobile ad-hoc networks (MANETs). Through the study of the delivery of a live encoded video stream, we expose the characteristics of different routing protocols and the infeasibility to provide QoS. The analysis shows the impact of a MANET on H.264 real-time video flows in terms of packet loss, end-to-end delay, jitter and distortion, and the behavior of H.264 error resilience tools in order to determine their effectiveness on such network scenarios. The results show that video traffic has demands that are hard to be met by a standard MANET, and that improvements are required in terms of routing protocols and QoS provision…
Rough Set Theory for Optimization of Packet Management Mechanism in IP Routers
2020
Bandwidth and consequently optimum overall efficiency of network system relies greatly on mechanism of packet management in IP routers. Our research objective is to implement rough set theory to minimizing number of the network system attributes responsible for decision making in selection of those packets, which improve its transmission. Such an approach is called priority queuing system model, as we assign priority to the packets selected, following rough set theory. Regardless of the file format, for all the routers, packets are transmitted in sequence one-by-one. Nonetheless, quality of streaming data largely depends on how much the packet loss is minimized, or eliminated at all, if pos…
MCD: Overcoming the Data Download Bottleneck in Data Centers
2013
The data download problem in data centers describes the increasingly common task of coordinated loading of identical data to a large number of nodes. Data download is seen as a significant problem in exascale HPC applications. Uncoor-dinated reading from a central file server creates contention at the file server and its network interconnect. We propose and evaluation a reliable multicast based approach to solve the data download problem. The MCD system builds a logical multi-rooted tree based on the physical network topology and uses the logical view for a two-phase approach. In the first phase, the data is multicasted to all nodes. In the second phase, the logical tree is used for an effi…
Performance of frame transmissions and event-triggered sleeping in duty-cycled WSNs with error-prone wireless links
2018
Abstract Two types of packet transmission schemes are prevalent in duty-cycled wireless sensor networks, i.e., single packet transmission and aggregated packet transmission which integrates multiple packets in one frame. While most existing models are developed based on an error-free channel assumption, this paper evaluates the performance of both transmission schemes under error-prone channel conditions. We develop a four-dimensional discrete-time Markov chain model to investigate the impact of channel impairments on the performance of frame transmissions. Together with tracking the number of packets in the queue, number of retransmissions and number of active nodes, the fourth dimension o…
Implementation and Deployment Evaluation of the DMAMAC Protocol for Wireless Sensor Actuator Networks
2016
Abstract The increased application of wireless technologies including Wireless Sensor Actuator Networks (WSAN) in industry has given rise to a plethora of protocol designs. These designs target metrics ranging from energy efficiency to real-time constraints. Protocol design typically starts with a requirements specification, and continues with analytic and model-based simulation analysis. State-of- the-art network simulators provide extensive physical environment emulation, but still have limitations due to model abstractions. Deployment testing on actual hardware is therefore vital in order to validate implementability and usability in the real environment. The contribution of this article…
Characterization of IP-Based Communication for Smart Grid Using Software-Defined Networking
2018
The smart grid (SG) approach is based on a strong interaction between the network communication infrastructure and the power grid. Usually the management of the infrastructure is done by the distribution system operators (DSOs) that are worried about the increasing managing complexity due to the presence of increasing number of distributed energy resources and electrical vehicles. The use of software-defined networking (SDN) may simplify the network configuration and management for DSO, as highlighted from previous research works. The objective of this paper is to introduce and characterize an internet protocol (IP)-based communication architecture with specialized SDN bridges operating als…
An intrusion detection system for selective forwarding attack in IPv6-based mobile WSNs
2017
Selective forwarding attack is considered among the most dangerous attack in wireless sensor networks, particularly in mobile environment. The attackers compromise legitimate nodes and selectively drop some packets. In addition to that, the movement of some nodes increases link failures, collisions and packet loss. So, it will be more difficult to detect malicious nodes from legitimates ones. This paper focuses on detecting selective forwarding attackers in IPv6-based mobile wireless sensor networks when the standardized IPv6 Routing Protocol for Low Power and Lossy Networks (RPL) is used. Contrarily to previous works which propose solutions to detect selective forwarding attack in static w…