3,076 research outputs found
WIMAX TESTBED
WiMAX, the Worldwide Interoperability for Microwave Access, is a
telecommunications technology aimed at providing wireless data over long distances
in a variety of ways, from point-to-point links to full mobile cellular type access. It is
based on the IEEE 802.16 standard, which is also called Wire IessMAN. The name
WiMAX was created by the WiMAX Forum, which was formed in June 2001 to
promote conformance and interoperability of the standard. The forum describes
WiMAX as a standards-based technology enabling the delivery of last mile wireless
broadband access as an alternative to cable and DSL. This Final Year Project attempts
to simulate via Simulink, the working mechanism of a WiMAX testbed that includes
a transmitter, channel and receiver. This undertaking will involve the baseband
physical radio link. Rayleigh channel model together with frequency and timing
offsets are introduced to the system and a blind receiver will attempt to correct these
offsets and provide channel equalization. The testbed will use the Double Sliding
Window for timing offset synchronization and the Schmid! & Cox algorithm for
Fractional Frequency Offset estimation. The Integer Frequency Offset
synchronization is achieved via correlation of the incoming preamble with its local
copy whereas Residual Carrier Fr~quency Offset is estimated using the L th extension
method. A linear Channel Estimator is added and combined with all the other blocks
to form the testbed. From the results, this testbed matches the standard requirements
for the BER when SNR is 18dB or higher. At these SNRs, the receiver side of the
testbed is successful in performing the required synchronization and obtaining the
same data sent. Sending data with SNR lower than 18dB compromises its
performance as the channel equalizer is non-linear. This project also takes the first
few steps of hardware implementation by using Real Time Workshop to convert the
Simulink model into C codes which run outside MATLAB. In addition, the Double
Sliding Window and Schmid! & Cox blocks are converted to Xilinx blocks and
proven to be working like their Simulink counterparts
Pedestrian Navigation using Artificial Neural Networks and Classical Filtering Techniques
The objective of this thesis is to explore the improvements achieved through using classical filtering methods with Artificial Neural Network (ANN) for pedestrian navigation techniques. ANN have been improving dramatically in their ability to approximate various functions. These neural network solutions have been able to surpass many classical navigation techniques. However, research using ANN to solve problems appears to be solely focused on the ability of neural networks alone. The combination of ANN with classical filtering methods has the potential to bring beneficial aspects of both techniques to increase accuracy in many different applications. Pedestrian navigation is used as a medium to explore this process using a localization and a Pedestrian Dead Reckoning (PDR) approach. Pedestrian navigation is primarily dominated by Global Positioning System (GPS) based navigation methods, but urban and indoor environments pose difficulties for using GPS for navigation. A novel urban data set is created for testing various localization and PDR based pedestrian navigation solutions. Cell phone data is collected including images, accelerometer, gyroscope, and magnetometer data to train the ANN. The ANN methods are explored first trying to achieve a low root mean square error (RMSE) of the predicted and original trajectory. After analyzing the localization and PDR solutions they are combined into an extended Kalman Filter (EKF) to achieve a 20% reduction in the RMSE. This takes the best localization results of 35m combined with underperforming PDR solution with a 171m RMSE to create an EKF solution of 28m of a one hour test collect
Target Tracking in UWB Multistatic Radars
Detection, localization and tracking of non-collaborative objects moving inside an area is of great interest to many surveillance applications. An ultra-
wideband (UWB) multistatic radar is considered as a good infrastructure
for such anti-intruder systems, due to the high range resolution provided by
the UWB impulse-radio and the spatial diversity achieved with a multistatic
configuration.
Detection of targets, which are typically human beings, is a challenging
task due to reflections from unwanted objects in the area, shadowing, antenna
cross-talks, low transmit power, and the blind zones arised from intrinsic peculiarities of UWB multistatic radars.
Hence, we propose more effective detection, localization, as well as clutter
removal techniques for these systems. However, the majority of the thesis
effort is devoted to the tracking phase, which is an essential part for improving
the localization accuracy, predicting the target position and filling out the
missed detections.
Since UWB radars are not linear Gaussian systems, the widely used tracking filters, such as the Kalman filter, are not expected to provide a satisfactory performance. Thus, we propose the Bayesian filter as an appropriate
candidate for UWB radars. In particular, we develop tracking algorithms
based on particle filtering, which is the most common approximation of
Bayesian filtering, for both single and multiple target scenarios. Also, we
propose some effective detection and tracking algorithms based on image
processing tools.
We evaluate the performance of our proposed approaches by numerical
simulations. Moreover, we provide experimental results by channel measurements for tracking a person walking in an indoor area, with the presence of a
significant clutter. We discuss the existing practical issues and address them by proposing more robust algorithms
Histogram equalization for robust text-independent speaker verification in telephone environments
Word processed copy.
Includes bibliographical references
Tracking with Sparse and Correlated Measurements via a Shrinkage-based Particle Filter
This paper presents a shrinkage-based particle filter
method for tracking a mobile user in wireless networks. The
proposed method estimates the shadowing noise covariance
matrix using the shrinkage technique. The particle filter is
designed with the estimated covariance matrix to improve the
tracking performance. The shrinkage-based particle filter can
be applied in a number of applications for navigation, tracking
and localization when the available sensor measurements are
correlated and sparse. The performance of the shrinkage-based
particle filter is compared with the posterior Cramer-Rao lower
bound, which is also derived in the paper. The advantages
of the proposed shrinkage-based particle filter approach are
demonstrated via simulation and experimental results
Vibration Monitoring: Gearbox identification and faults detection
L'abstract è presente nell'allegato / the abstract is in the attachmen
- …