A. D. Reis

Experimental Performance Study of a Very High Speed Free Space Optics Link at the University of Beira Interior Campus: a Case Study

A very high speed FSO (free space optics) link has been successfully implemented for purposes of high requirement applications, at the University Campus. An experimental performance evaluation of this link has been carried out at various OSI levels (1, 4, and 7). Several results are presented and discussed.

WI-FI Point-to-Point Links: Performance Aspects of IEEE 802.11a, b, g Laboratory Links

Wireless communications using microwaves are increasingly important, e.g. Wi-Fi. Performance is a very relevant issue, resulting in more reliable and efficient communications. Laboratory measurements are made about several performance aspects of Wi-Fi (IEEE 802.11 a, b, g) point-to-point links using two types of access points from Enterasys Networks (RBT-4102 and RBTR2). Through OSI levels 3, 4 and 7, detailed results are presented and discussed, namely: latency, ICMP packet loss, TCP throughput, jitter, percentage datagram loss and FTP transfer rate.

Laboratory performance of wi-fi point-to-point links: A case study

Experimental laboratory measurements are made about several performance aspects of IEEE 802.11a, b, g point-to-point links, using Enterasys Networks access points (RBTR2). Detailed results are presented and discussed at OSI levels 1, 3, 4 and 7: SNR, latency, ICMP packet loss, TCP throughput, jitter, percentage datagram loss, and FTP transfer rate.

Experimental development and study of Wi-Fi and FSO links

Wi-Fi, using 2.4 GHz microwaves and IEEE 802.11b/g standards, is mainly applied to the development of outdoor wireless links. In addition, a FSO link is implemented for data and voice communications. Link quality has been tested. Several results are presented and discussed.

Wi-Fi Wep Point-to-Point Links

The importance of wireless communications has been growing. Performance is a crucial issue, resulting in more reliable and efficient communications. Security is equally important. Laboratory measurements are made about several performance aspects of Wi-Fi (IEEE 802.11a, b, g) WEP point-to-point links. A contribution is given to performance evaluation of this technology, using two types of access points from Enterasys Networks (RBT-4102 and RBTR2). Detailed results are presented and discussed, namely at OSI levels 4 and 7, from TCP, UDP and FTP experiments: TCP throughput, jitter, percentage datagram loss and FTP transfer rate. Comparisons are made to corresponding results obtained for open links. Conclusions are drawn about the comparative performance of the links.

Extended Performance Research on Wi-Fi IEEE 802.11 a, b, g Laboratory Open Point-to-Multipoint and Point-to-Point Links

The increasing importance of wireless communications, involving electronic devices, has been widely recognized. Performance is a crucial issue, leading to more reliable and efficient communications. Laboratory measurements were performed about several performance aspects of Wi-Fi (IEEE 802.11 a, b, g) Open point-to-multipoint links. Our study contributes to the performance evaluation of this technology, using new available equipments (V-M200 access points from HP and WPC600N adapters from Linksys). New detailed results are presented and discussed, namely at OSI levels 4 and 7, from TCP, UDP and FTP experiments: TCP throughput, jitter, percentage datagram loss and FTP transfer rate. Comparisons are made to corresponding results obtained for Open point-to-point links. Conclusions are drawn about the comparative performance of the links.

Extended Field Performance Evaluation of a Gbps FSO Link

Wireless communications have been increasingly important. Besides Wi-Fi, FSO plays a very relevant technological role in this context. Performance is crucial, resulting in more reliable and efficient communications. A FSO medium range link has been successfully implemented for high requirement applications at Gbps. An extended field performance evaluation of this link has been carried out at OSI layers 1, 4 and 7, through a specifically planned field test arrangement. Measurements have been made both for powers received by the laser heads, and TCP, UDP and FTP experiments, resulting in determinations of TCP throughput, jitter, percentage datagram loss and FTP transfer rate. Corresponding results are presented and discussed. Conclusions are drawn about link performance.

Extended Performance Studies of Wi-Fi IEEE 802.11 A, B, G Laboratory Wep Point-to-Multipoint and Point-to-Point Links

Wireless communications using microwaves are increasingly important, such as Wi-Fi. Performance is a most fundamental issue, leading to more reliable and efficient communications. Security is equally very important. Laboratory measurements were performed on several performance aspects of Wi-Fi (IEEE 802.11a, b, g) WEP point-to-multipoint links. Our study contributes to performance evaluation of this technology, using available equipments (DAP-1522 access points from D-Link and WPC600N adapters from Linksys). New detailed results are presented and discussed, namely at OSI levels 4 and 7, from TCP, UDP and FTP experiments: TCP throughput, jitter, percentage datagram loss and FTP transfer rate. Comparisons are made to corresponding results obtained for WEP point-to-point and Open point-to-multipoint links. Conclusions are drawn about the comparative performance of the links.

Asynchronous sequential symbol synchronizers based on pulse comparison by positive transitions at half bit rate

This work studies the asynchronous sequential symbol synchronizers based on pulse comparison by both transitions at rate (atx). Their performance will be compared with the reference synchronous synchronizers based on pulse comparison by both transitions at rate (stx). For the reference and proposed variants, we consider two versions which are the manual (m) and the automatic (a). The objective is to study the four synchronizers and evaluate their output jitter UIRMS (Unit Interval Root Mean Square) versus input SNR (Signal Noise Ratio).

TCP, UDP and FTP Performances of Laboratory Wi-Fi IEEE 802.11g WEP Point-to-Point Links

Wireless communications, e.g. Wi-Fi, have been increasingly important in the context of networked and virtual organizations and enterprise information systems. Performance is an issue of fundamental importance, resulting in more reliable and efficient communications, therefore improving enterprise information system yield. Security is equally important. Laboratory measurements are made about several performance aspects of Wi-Fi IEEE 802.11g WEP point-to-point links. A contribution is given to performance evaluation of this technology under WEP encryption, using available access points from Enterasys Networks (RBT-4102). Detailed results are presented and discussed, namely at OSI levels 4 and 7, from TCP, UDP and FTP experiments, permitting measurements of TCP throughput, jitter, percentage datagram loss and FTP transfer rate. Comparisons are made to corresponding results obtained for open links. Conclusions are drawn about the comparative performance of the links..