1,001 research outputs found
Final report on the evaluation of RRM/CRRM algorithms
Deliverable public del projecte EVERESTThis deliverable provides a definition and a complete evaluation of the RRM/CRRM algorithms selected in D11 and D15, and evolved and refined on an iterative process. The evaluation will be carried out by means of simulations using the simulators provided at D07, and D14.Preprin
Performance evaluation of TCP over IEEE 80211 WLANs
Transmission Control Protocol (TCP) is a communication protocol that is used to provide reliable data delivery between hosts. As TCP is the most highly used transport-layer protocol, many have worked on addressing the issue of performance. Performance issues have been studied in various environments, especially when using 802.11 Wireless Local Area Networks (WLANs). Wireless networks are prone to a higher number of packets loss and corruption. 802.11 WLANs have an equivalently fast acknowledgement mechanism as TCP to ensure reliability of traffic over it. This duplication of functionality between TCP and 802.11 WLAN creates unexpected behaviors that can result in high costs in terms of overall performance. A significant amount of analytical and simulation work has been done in the past to study the behaviour of TCP over 802.11 WLANs. The main contribution of this work is the analysis of TCP interaction in an 802.11 WLAN topology by using real commercial-grade equipments.
A testing methodology is designed to, do the quantitative performance evaluation in a network topology consisted of wired as well as a wireless connection. The methodology contains test scenarios with different configurable settings on an Access Point (AP) and various controlled impairments in the network topology such as latency, packet drop, noise interference, etc. The performance of TCP is measured in terms of the throughput.
This work provides a comprehensive set of experiments to study the behaviour of TCP over 802.11 WLANs. The results can provide insight into the performance cost associated with TCP traffic on 802.11 WLANs under different network environments and configurations on the AP. The results of this work thus have a value to equipment manufacturers and network operators
EVEREST IST - 2002 - 00185 : D23 : final report
Deliverable pĂșblic del projecte europeu EVERESTThis deliverable constitutes the final report of the project IST-2002-001858 EVEREST. After its successful completion, the project presents this document that firstly summarizes the context, goal and the approach objective of the project. Then it presents a concise summary of the major goals and results, as well as highlights the most valuable lessons derived form the project work. A list of deliverables and publications is included in the annex.Postprint (published version
VoIP over WLAN: What about the Presence of Radio Interference?
In this chapter, the performance of VoIP over WLAN is analyzed under the effect of physical
layer interference, in the presence and absence of cross-traffic. The goal is twofold: first to
underline the importance of radio interference in the behavior of a WLAN when supporting
VoIP applications; second to outline solutions to avoid interference and thus optimizing a VoIP
call over aWLAN. To this aim, an experimental approach based on cross-layermeasurements
is adopted, describing and commenting meaningful results
obtained from a number of experiments conducted by the authors on a testbed operating
in a semi-anechoic chamber and emulating two typical real life scenarios
Improving the Performance of Wireless LANs
This book quantifies the key factors of WLAN performance and describes methods for improvement. It provides theoretical background and empirical results for the optimum planning and deployment of indoor WLAN systems, explaining the fundamentals while supplying guidelines for design, modeling, and performance evaluation. It discusses environmental effects on WLAN systems, protocol redesign for routing and MAC, and traffic distribution; examines emerging and future network technologies; and includes radio propagation and site measurements, simulations for various network design scenarios, numerous illustrations, practical examples, and learning aids
Measuring Transmission Opportunities in 802.11 Links
We propose a powerful MAC/PHY cross-layer approach
to measuring IEEE 802.11 transmission opportunities in
WLAN networks on a per-link basis. Our estimator can operate
at a single station and it is able to: 1) classify losses caused by
noise, collisions, and hidden nodes; and 2) distinguish between
these losses and the unfairness caused by both exposed nodes and
channel capture. Our estimator provides quantitative measures of
the different causes of lost transmission opportunities, requiring
only local measures at the 802.11 transmitter and no modification
to the 802.11 protocol or in other stations. Our approach is suited
to implementation on commodity hardware, and we demonstrate
our prototype implementation via experimental assessments. We
finally show how our estimator can help the WLAN station to
improve its local performance
An overview of link-level measurement techniques for wide-area wireless networks
By building wireless link-level measurement tools we hope to improvement the design, deployment and management of wide-area wireless community networks. This paper identifies existing link-level measurement techniques and discusses the advantages and disadvantages of each in the context of measuring and monitoring such networks. Finally, we make a case for the need for more sophisticated techniques and tools which will assist both day-to-day network operations as well as wireless network research
- âŠ