Search results for "ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS"
showing 10 items of 449 documents
Additional file 2: of Living alone and positive mental health: a systematic review
2019
Review protocol. This file presents the protocol of the study. (DOC 93 kb)
Additional file 2: of Living alone and positive mental health: a systematic review
2019
Review protocol. This file presents the protocol of the study. (DOC 93 kb)
ARQ Aware Scheduling for the IEEE 802.16 Base Station
2008
The IEEE 802.16 technology defines the ARQ mechanism that enables a connection to resend data at the MAC level if an error is detected. In this paper, we analyze the ARQ aware scheduling for the 802.16 base station. In particular, we consider how the BS scheduler can account for the ARQ block size, absence of the ARQ block rearrangement, and the ARQ transmission window. We propose a set of constraints that can be applied to any base station scheduler algorithm. To test them, we run a number of simulation scenarios. The simulations results confirm that the ARQ aware scheduling can improve the overall performance.
Performance analysis of the ieee 802.16 arq mechanism
2007
The IEEE 802.16 technology defines the ARQ mechanism that enables a connection to resend data at the MAC level if an error is detected. In this paper, we analyze the key features and parameters of the 802.16 ARQ mechanism. In particular, we consider a choice for the ARQ feedback type, an algorithm to build block sequences, a scheduling of the ARQ feedbacks and retransmissions, the ARQ block rearrangement, ARQ transmission window and ARQ block size. We run a number of simulation scenarios to study these parameters and how they impact a performance of application protocols. The simulation results reveal that the ARQ mechanism and its correct configuration play an important role in transmittin…
On ARQ feedback intensity of the IEEE 802.16 ARQ mechanism
2008
The IEEE 802.16 standard defines the ARQ mechanism as a part of the MAC layer. The functioning of the ARQ mechanism depends on a number of parameters. The IEEE 802.16 specification defines them but it does not provide concrete values and solutions. We ran simulation scenarios to study how the ARQ feedback intensity impacts the performance of application protocols. The simulation results reveal that a low ARQ feedback intensity results only in a marginal improvement. Though it is possible to optimize the ARQ feedback intensity, it is reasonable to rely upon more frequent ARQ feedback messages as they do not result in a performance degradation. At the same time, ARQ connections, which work on…
Handover and Uplink Power Control Performance in the 3.84 Mcps TDD mode of UTRA Network
2003
In this article we consider the performance of the 3.84 Mcps time-division duplex (TDD) mode of UTRA (Universal Terrestrial Radio Access) network. We emphasize two of the radio resource management algorithms, handover and uplink power control, whose role in the overall system performance is studied extensively. First, a handover algorithm used in WCDMA (Wideband Code Division Multiple Access) standard is considered in a TDD-mode operation. This gives rise to a careful setting of different handover parameters, and the evaluation of the effects to the system performance. Secondly, the specified uplink power control algorithm is considered. Since it is based on several user-made measurements w…
Optimized Handover Algorithm Based on Stackelberg Games in CBTC Systems for Urban Rail Transit
2014
Communications Based Train Control (CBTC) systems have become indispensable for train operation to improve the safety and efficiency of train running to the utmost extent at present. In this paper, the problem of train handover in wireless LAN of CBTC systems for urban rail transit was taken into consideration, which was formulated as a market competition with Stackelberg games and cooperative diversity to obtain the reasonable resource allocation for trains. Under the environment of continuous train-to-wayside communications with high reliability, the successful train handover probability was analyzed in detail. Firstly, the relay triggering during handover was introduced, and the price st…
Adaptive Collision Avoidance through Implicit Acknowledgments in WSNs
2008
The large number of nodes, typical of many sensor network deployments, and the well-known hidden terminal problem make collision avoidance an essential goal for the actual employment of WSN technology. Collision avoidance is traditionally dealt with at the MAC Layer and plenty of different solutions have been proposed, which however have encountered limited diffusion because of their incompatibility with commonly available devices.In this paper we propose an approach to collision avoidance which is designed to work over a standard MAC Layer, namely the IEEE 802.15.4 MAC, and is based on application-controlled delays of packet transmission times. The proposed scheme is simple, decentralized …
Cooperative RTS/CTS MAC with relay selection in distributed wireless networks
2009
This paper proposes a cooperative multiple access protocol based on the Distributed Coordination Function (DCF) Request-To-Send/Clear-To-Send (RTS/CTS) scheme for distributed wireless networks. It answers three key questions concerning cooperation from the network perspective, namely when to cooperate, whom to cooperate with and how to protect cooperative transmissions. According to our protocol, the cooperation is initiated only if the direct transmission fails. An optimal relay node is selected in a distributed manner according to instantaneous relay channel conditions without prior information or extra signaling among relay candidates in the network. An additional three-way handshake is …
Sport Intervention Programs (SIPs) to Improve Health and Social Inclusion in People with Intellectual Disabilities: A Systematic Review.
2019
Inactivity is a major issue that causes physical and psychological health problems, especially in people with intellectual disability (ID). This review discusses the beneficial effects of sport intervention programs (SIPs) in people with ID, and aims to provide an overview of the scientific literature in order to identify the main factors influencing the participation of people with ID in SIPs. Twelve papers were analyzed and compared. The results show a large variety in examined SIPs, concerning participants’ age and disability, intervention characteristics and context, as well as measures and findings. The main factors essential for people with ID partaking in SIPs appeared to be suitabl…