Search results for "Network packet"
showing 10 items of 160 documents
Moderate-to-Strong Turbulence Generation in a Laboratory Indoor Free Space Optics Link and Error Mitigation via RaptorQ Codes
2016
Free Space Optics (FSO) is rapidly gaining interest as a line-of sight communication technology that offers capabilities similar - in terms of bandwidth and transfer rates - to optical fibre, also possessing several advantages compared with traditional radio frequency links. However, FSO link quality can be strongly affected by unfavourable weather conditions and also by the phenomenon of optical turbulence, even in clear sky. In this work, we have implemented an indoor FSO link and generated moderate-to-strong turbulence conditions along the optical path by using heaters and a mechanical ventilation system. In this way, we have been able to investigate the effects of the generated turbulen…
Performance Analysis of Synchronous Duty-Cycled MAC Protocols
2015
In this letter, we propose an analytical model to evaluate the performance of the S-MAC protocol. The proposed model improves the accuracy of previous models in two aspects. First, it incorporates the dependence among the nodes within a cluster by defining a DTMC that models the number of active nodes, whereas the previous models considered that nodes were mutually independent. Second, it proposes new methods for calculating packet delay and energy consumption. The analytical model is validated through discrete-event based simulations. Numerical results demonstrate that the proposed analytical model and methods yield accurate results under realistic assumptions
Link adaptation with combined optimal frame size and rate selection in error-prone 802.11n networks
2008
In error-prone channel with low SNRs, the network throughput may drop significantly if the packet length becomes too large. On the other hand, too much protocol overhead will be introduced if the packet length is too small. In this paper, we study this tradeoff and propose an adaptive frame size algorithm for A-MPDU in 802.11n networks, which can maximize the throughput by selecting the optimized frame length under different channel conditions. When used together with rate selection, the network throughput can be further improved. Both analytical model and simulation results are presented, demonstrating that our algorithm outperforms the fixed length transmission scheme in 802.11n networks …
Random Early Detection for Congestion Avoidance in Wired Networks: A Discretized Pursuit Learning-Automata-Like Solution
2010
Published version of an article in the journal: IEEE Transactions on Systems, Man, and Cybernetics, Part B: Cybernetics. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works In this paper, we present a learning-automata-like (LAL) mechanism for congestion avoidance in wired networks. Our algorithm, named as LAL random early detection (LALRED), is founded on the principles of the operations of existing RED con…
Wireless HROV Control with Compressed Visual Feedback Using Acoustic and RF Links
2020
AbstractUnderwater cooperative robotics offers the possibility to perform challenging intervention applications, such as recovering archeological objects as within the context of the MERBOTS research project, or grasping, transporting and assembly of big objects, using more than one mobile manipulator, as faced by the TWINBOT project. In order to enhance safety during the intervention, it is reasonable to avoid the umbilical, also giving more mobility to the robots, and enabling a broader set of cooperative movements. Several solutions, based on acoustic, radiofrequency (RF) or Visual Light Communication (VLC) have been proposed for underwater communications in the literature. This paper pr…
Packet management techniques for measurement based end-to-end admission control in IP networks
2000
End-to-end Measurement Based connection Admission Control (EMBAC) mechanisms have been proposed to support real-time flows quality of service requirements over a Differentiated Services Internet architecture. The EMBAC basic idea is to decentralize the admission control decision, by requiring each individual user to probe the network path during flow setup, and by basing the accept/reject decision on the probing traffic statistics measured at the destination. In conformance with the differentiated services framework, routers are oblivious to individual flows and only need to serve data packets with a higher priority than probing traffic. In this paper, we build upon the observation that som…
A Novel Fault-Tolerant Routing Technique for Mesh-of-Tree based Network-on-Chip Design
2018
Due to the increase in the number of processing elements in System-on-Chips (SoCs), communication between the cores is becoming complex. A solution to this issue in SoCs gave rise to a new paradigm called Network-on-Chips (NoCs). In NoCs, communication between different cores is achieved using packet based switching techniques. In the deep sub-micron technology, NoCs are more susceptible to different kinds of faults which can be transient, intermittent and permanent. These faults can occur at any component of NoCs. This paper presents a novel Fault-Tolerant Routing (FTR) technique for Mesh-of-Tree (MoT) topology in the presence of router faults. The proposed technique is compared with routi…
Fault Tolerant Routing Methodology for Mesh-of-Tree based Network-on-Chips using Local Reconfiguration
2018
Increase in the processing elements in a System-on- Chip (SoC) has led to an increasing complexity between the cores in the entire network. This communication bottleneck led to rise in the new paradigm called Network-on-Chip (NoC). These NoC are very much susceptible to various types of faults which can be transient, intermittent or permanent. This paper presents a fault-tolerant routing technique which can route the packets from a source to a destination in presence of permanent faults in the leaf routers of Mesh-of-Tree topology where cores are connected. This is achieved by using reconfiguration in the local ports of the leaf routers by inserting multiplexers as a layer between the leaf …
An API for Advanced Traffic Control in Diffserv Routers
2003
Distributed per-flow admission control is a promising solution for Differentiated Services networks. Its deployment in DiffSery domains requires the ability to suitably configure, in each network router, low-level packet forwarding mechanisms, such as packet dropping algorithms driven by traffic measurements. In this paper we first show that performance effectiveness is achieved by means of non traditional configuration of the forwarding mechanisms. Hence, we propose a modular Application Program Interface that allows to flexibly and adaptively configure the forwarding/dropping behavior associated to a router’s output queue, well beyond the traditional RED/RIO active queue management scheme…
A TDMA-Based MAC Protocol Supporting Cooperative Communications in Wireless Mesh Networks
2011
This paper proposes a TDMA-based medium access control protocol which enables cooperative communications in multi-hop wireless mesh networks. According to the proposed scheme, each router at the two-hop neighbourhood of each other is allocated to a specific time slot for accommodating either direct or cooperative transmissions in a coordinated manner, controlled by mini-slots which are part of the time slot. Benefiting from the elaborate mini-slot design, channel resources are fairly and efficiently allocated to each router so that no handshake is needed prior to each packet transmission. By providing access priority to cooperative transmission through an optimal relay which is determined b…