Search results for "Organization"
showing 10 items of 4550 documents
Energy-Efficient Binary Power Control with Bit Error Rate Constraint in MIMO-OFDM Wireless Communication Systems
2012
Motivated by the demand for energy efficiency improvement in mobile communication industry, we explore an idea of optimizing energy efficiency for MIMO-OFDM wireless communication systems while maintaining users' quality of service (QoS) requirement. Based on the binary power control scheme,a power allocation criterion for energy efficiency optimization is derived under the total power constraint. From a bit error rate (BER) point of view, a protection constraint is configured to guarantee the system QoS. With the aim of energy efficiency optimization under QoS guarantee in MIMO-OFDM wireless communication systems, an energy-efficient binary power control with BER constraint (EBPCB) algorith…
Study of transmission parameters under controlled multipath environment using Rasp Pi3
2018
The evaluation of QoS in mobile multipath environments is an interesting topic in modern communications. The use of Raspberry Pi as a low cost microcomputer board developed in the United Kingdom by the Raspberry Pi Foundation can be helpful in onsite deployments. The Pi3 model has integrated WiFi and Bluetooth connectivity and also 4 USB ports to expand the device with all kinds of peripheral. Under the premise of offering the power of a computer at low prices, this device is one of the most affordable ways to have a particularly efficient and dynamic hardware accessible at a low price to develop a Wireless Sensor Netwok (WSN). The use of the Raspberry Pi3 permits the development of a power…
Efficiency analysis of burst transmissions with block ACK in contention-based 802.11e WLANs
2005
The channel utilization efficiency of the standard 802.11 networks is severely compromised when high data transmission rates are employed, since physical layer headers and control frames are transmitted at low rate, thus wasting more channel time, proportionally. The extensions defined in the emerging 802.11e for quality-of-service (QoS) provisioning include some new mechanisms developed in order to improve the efficiency. Those include data transmission bursting (referred to as TXOP operation) and acknowledgment aggregation (referred to as block ACK). These two features allow it to offer new data transmission services, in which the data delivery and acknowledgment unit is not a single fram…
WLC24-1: Dynamic MAC Parameters Configuration for Performance Optimization in 802.11e Networks
2006
Quality of service support in wireless LAN is a theme of current interest. Several solutions have been proposed in literature in order to protect time-sensitive traffic from best-effort traffic. According to the EDCA proposal, which is a completely distributed solution, the service differentiation is provided by giving probabilistically higher number of channel accesses to stations involved in real-time applications. To this purpose, the MAC parameter settings of each contending stations can be tuned dynamically. In this paper, we face the problem of tuning the EDCA MAC parameters in common scenarios in which a given number of low-rate delay-sensitive traffic flows share the channel with so…
Efficient Hybrid Emergency Aware MAC Protocol for Wireless Body Sensor Networks
2018
International audience; In Body Sensor Networks (BSNs), two types of events should be addressed: periodic and emergency events. Traffic rate is usually low during periodic observation, and becomes very high upon emergency. One of the main and challenging requirements of BSNs is to design Medium Access Control (MAC) protocols that guarantee immediate and reliable transmission of data in emergency situations, while maintaining high energy efficiency in non-emergency conditions. In this paper, we propose a new emergency aware hybrid DTDMA/DS-CDMA protocol that can accommodate BSN traffic variations by addressing emergency and periodic traffic requirements. It takes advantage of the high delay …
¿Cómo funciona el sistema de innovación del sector cerámico español?
2013
[EN]: In this article we apply the functions of innovation systems framework to assess its appropriateness to characterise the innovation activity of the tile industry in Castellón. This framework is based on idea that a well functioning innovation system requires that a number of key activities take place. If this occurs innovative output is higher. Our analysis provides a deeper understanding of the role of innovation as a strategic option in a mature industry in the context of globalisation. By applying this new theoretical approach to study innovation and highlighting the functions that the system requires, we shown the constraints, inertias, challenges and opportunities that the innova…
Model-based verification of the DMAMAC protocol for real-time process control
2015
Medium Access Control (MAC) protocols are responsible for managing radio communication that constitute the main energy consumer in wireless sensor-actuator networks. The Dual-Mode Adaptive MAC (DMAMAC) protocol is a recently proposed MAC protocol for process control applications within industrial automation. The goal of the DMAMAC protocol is to improve energy efficiency along with addressing real-time requirements for process control applications. The DMAMAC protocol switches between two operational modes that correspond to the two main states in process control: the transient state and the steady state. The state-switch is a safety critical function of the DMAMAC protocol (along with othe…
Fault-tolerant routing in adversarial mobile ad hoc networks: an efficient route estimation scheme for non-stationary environments
2010
Published version of an article from the journal: Telecommunication systems. The original publication is available at Spingerlink. http://dx.doi.org/DOI: 10.1007/s11235-009-9215-4 Designing routing schemes that would successfully operate in the presence of adversarial environments in Mobile Ad Hoc Networks (MANETs) is a challenging issue. In this paper, we discuss fault-tolerant routing schemes operating in a network with malfunctioning nodes. Most existing MANET protocols were postulated considering scenarios where all the mobile nodes in the ad hoc network function properly, and in an idealistic manner. However, adversarial environments are common in MANET environments, and misbehaving no…
Cooperative Medium Access Mechanisms and Service-oriented Routing in Multi-hop Wireless Networks
2011
Doktorgradsavhandling i informasjons- og kommunikasjonsteknologi, Universitetet i Agder, Grimstad, 2011 Multi-hop wireless networks have been regarded as a promising path towards future wireless communication landscape. In the past decade, most related work has been performed in the context of mobile ad hoc networks. In very recent years, however, much effort has been shifted to more static networks such as wireless mesh networks and wireless sensor networks. While significant progress has been achieved through these years, both theoretically and experimentally, challenges still exist in various aspects of these networks. For instance, how to use multi-hop networks as a means for providing …
Cooperative retransmission implementation in ns 2
2010
Masteroppgave i informasjons- og kommunikasjonsteknologi 2010 – Universitetet i Agder, Grimstad From the theoretical perspective cooperative communications are reasonably well understood. But in practical realizations of cooperative communication system are still quite limited, the articles in this special issue are devoted to implementation aspects related to cooperative retransmission implementation in ns 2.system..Cooperative retransmission in wireless networks has attracted many research attentions which is the basic idea when a receiver cannot decode a frame, the retransmission is handled not by its original source but rather by a neighbor that overheard the transmission successfully, …