18,972 research outputs found
Analyzing Delay in Wireless Multi-hop Heterogeneous Body Area Networks
With increase in ageing population, health care market keeps growing. There
is a need for monitoring of health issues. Wireless Body Area Network (WBAN)
consists of wireless sensors attached on or inside human body for monitoring
vital health related problems e.g, Electro Cardiogram (ECG), Electro
Encephalogram (EEG), ElectronyStagmography (ENG) etc. Due to life threatening
situations, timely sending of data is essential. For data to reach health care
center, there must be a proper way of sending data through reliable connection
and with minimum delay. In this paper transmission delay of different paths,
through which data is sent from sensor to health care center over heterogeneous
multi-hop wireless channel is analyzed. Data of medical related diseases is
sent through three different paths. In all three paths, data from sensors first
reaches ZigBee, which is the common link in all three paths. Wireless Local
Area Network (WLAN), Worldwide Interoperability for Microwave Access (WiMAX),
Universal Mobile Telecommunication System (UMTS) are connected with ZigBee.
Each network (WLAN, WiMAX, UMTS) is setup according to environmental
conditions, suitability of device and availability of structure for that
device. Data from these networks is sent to IP-Cloud, which is further
connected to health care center. Delay of data reaching each device is
calculated and represented graphically. Main aim of this paper is to calculate
delay of each link in each path over multi-hop wireless channel.Comment: arXiv admin note: substantial text overlap with arXiv:1208.240
Network on Chip: a New Approach of QoS Metric Modeling Based on Calculus Theory
A NoC is composed by IP cores (Intellectual Propriety) and switches connected
among themselves by communication channels. End-to-End Delay (EED)
communication is accomplished by the exchange of data among IP cores. Often,
the structure of particular messages is not adequate for the communication
purposes. This leads to the concept of packet switching. In the context of
NoCs, packets are composed by header, payload, and trailer. Packets are divided
into small pieces called Flits. It appears of importance, to meet the required
performance in NoC hardware resources. It should be specified in an earlier
step of the system design. The main attention should be given to the choice of
some network parameters such as the physical buffer size in the node. The EED
and packet loss are some of the critical QoS metrics. Some real-time and
multimedia applications bound up these parameters and require specific hardware
resources and particular management approaches in the NoC switch. A traffic
contract (SLA, Service Level Agreement) specifies the ability of a network or
protocol to give guaranteed performance, throughput or latency bounds based on
mutually agreed measures, usually by prioritizing traffic. A defined Quality of
Service (QoS) may be required for some types of network real time traffic or
multimedia applications. The main goal of this paper is, using the Network on
Chip modeling architecture, to define a QoS metric. We focus on the network
delay bound and packet losses. This approach is based on the Network Calculus
theory, a mathematical model to represent the data flows behavior between IPs
interconnected over NoC. We propose an approach of QoS-metric based on
QoS-parameter prioritization factors for multi applications-service using
calculus model
Fast, Accurate and Detailed NoC Simulations
Network-on-Chip (NoC) architectures have a wide variety of parameters that can be adapted to the designer's requirements. Fast exploration of this parameter space is only possible at a high-level and several methods have been proposed. Cycle and bit accurate simulation is necessary when the actual router's RTL description needs to be evaluated and verified. However, extensive simulation of the NoC architecture with cycle and bit accuracy is prohibitively time consuming. In this paper we describe a simulation method to simulate large parallel homogeneous and heterogeneous network-on-chips on a single FPGA. The method is especially suitable for parallel systems where lengthy cycle and bit accurate simulations are required. As a case study, we use a NoC that was modelled and simulated in SystemC. We simulate the same NoC on the described FPGA simulator. This enables us to observe the NoC behavior under a large variety of traffic patterns. Compared with the SystemC simulation we achieved a speed-up of 80-300, without compromising the cycle and bit level accuracy
PluralisMAC: a generic multi-MAC framework for heterogeneous, multiservice wireless networks, applied to smart containers
Developing energy-efficient MAC protocols for lightweight wireless systems has been a challenging task for decades because of the specific requirements of various applications and the varying environments in which wireless systems are deployed. Many MAC protocols for wireless networks have been proposed, often custom-made for a specific application. It is clear that one MAC does not fit all the requirements. So, how should a MAC layer deal with an application that has several modes (each with different requirements) or with the deployment of another application during the lifetime of the system? Especially in a mobile wireless system, like Smart Monitoring of Containers, we cannot know in advance the application state (empty container versus stuffed container). Dynamic switching between different energy-efficient MAC strategies is needed. Our architecture, called PluralisMAC, contains a generic multi-MAC framework and a generic neighbour monitoring and filtering framework. To validate the real-world feasibility of our architecture, we have implemented it in TinyOS and have done experiments on the TMote Sky nodes in the w-iLab.t testbed. Experimental results show that dynamic switching between MAC strategies is possible with minimal receive chain overhead, while meeting the various application requirements (reliability and low-energy consumption)
Future benefits and applications of intelligent on-board processing to VSAT services
The trends and roles of VSAT services in the year 2010 time frame are examined based on an overall network and service model for that period. An estimate of the VSAT traffic is then made and the service and general network requirements are identified. In order to accommodate these traffic needs, four satellite VSAT architectures based on the use of fixed or scanning multibeam antennas in conjunction with IF switching or onboard regeneration and baseband processing are suggested. The performance of each of these architectures is assessed and the key enabling technologies are identified
Design of an integrated airframe/propulsion control system architecture
The design of an integrated airframe/propulsion control system architecture is described. The design is based on a prevalidation methodology that uses both reliability and performance. A detailed account is given for the testing associated with a subset of the architecture and concludes with general observations of applying the methodology to the architecture
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