B. S. L. Castro

Comparison between known propagation models using least squares tuning algorithm on 5.8 GHz in Amazon region cities

This paper presents a performance comparison between known propagation Models through least squares tuning algorithm for 5.8 GHz frequency band. The studied environment is based on the 12 cities located in Amazon Region. After adjustments and simulations, SUI Model showed the smaller RMS error and standard deviation when compared with COST231-Hata and ECC-33 models.

Cross layer model to predict performance parameters on OFDM-based wireless networks

This paper presents a propagation model for prediction of path loss and performance parameters (throughput and frame loss) on OFDM-based networks. For this study, measurements on a 5.8 GHz Wimax network were carried out. The proposed model parameters have been adjusted by LS (Least Squares) optimization, using measured data as reference. The results show that the proposed model has a good agreement with the measurements. Futures works can consider an adjustment for a set of frequencies. For this purpose, extensive measurements campaigns will be carried out.

Multimedia transmission on Amazon region using wireless broadband networks

This work presents results for multimedia transmission using wireless broadband networks installed in some remote cities in Amazon region. In 15 cities at State of Pará, Brazil, the local government is installing wireless networks to provide wideband internet access to public agents, such as schools, hospitals, police stations and office buildings in a great project named NavegaPará. Each city has a base station working on 5.7 GHz and serving around 30 subscribers, which use an individual broadband transceiver (IBT) to access the network. The aggregate throughput (downstream + upstream) for each client is 7 Mbps, 14 Mbps or 30 Mbps depending on the installed equipment and the distance between the base station and the client unit. It is presented a typical scenario for multimedia transmission using the available infrastructure. In this case, an IBT is connected directly to a computer, which is connected to a video camera transmitting video traffic. The available infrastructure is useful for broadcasting the public television signal (Funtelpa) in uncovered areas of State of Pará. Metrics such as throughput and latency are collected and analyzed. Obtained results show that multimedia transmission using NavegaPará infrastructure has satisfactory results.

A methodology to minimize the measured points for project an indoor WLAN

The main goal of this paper is to propose a methodology to determine the minimum number of measurement points in an indoor environment for a 2.4 GHz Wireless Local Area Network (WLAN) project. For validate this methodology, measurement campaigns was accomplished in two buildings (indoor environments), using an access point as signal transmitter, and a notebook computer as receiver, equipped with a wireless board. Collected data have been expanded using a generalized regressor. Propagation loss computation has been made using the expanded data in an adapted Pade Approximant model from the total points. Results obtained show that the methodology can be applied successfully.

A methodology for evaluation of video quality loss on OFDM-based networks due to channel conditions

This paper presents a methodology for evaluation of video quality on OFDM-based networks. For such a purpose, measurements on a 5.8 GHz Wimax network were carried out in a controlled environment. The proposed methodology is based on mapping the PSNR (Peak Signal-to-Noise Ratio) loss on SNR (Signal-to-Noise ratio) values in a cross-layer analysis. This is achieved by reducing the base station transmitted power, simulating a SNR reduction. The results show that the channel degradation (SNR reduction) is directly related to video quality loss.