Electrical and Electronics Commons^™

A Sip Based Multimedia Messaging Service, Donna Griffin

Theses

The Session Initiation Protocol (SIP) is the protocol of choice for establishing multimedia sessions in Universal Mobile Telecommunications System (UMTS) networks as stated by 3GPP. SIP is a protocol that will merge together the cellular and Internet worlds and is also scalable, highly available and extensible. It enables mobile carriers to extend operations, administration, maintenance and provisioning (OAMP) in one application to all applications. In addition, while SIP permits presence. Instant Messaging, File Sharing etc., its ultimate value lies in seamlessly aggregating these applications in more powerful offerings, such as Multimedia Messaging, Push to Talk and Voice over IP.

Multimedia …

Performance Estimation Of A Sip Based Push-To-Talk Service For 3g Wireless Networks, Eoin O'Regan

Theses

Push To Talk (PTT) services have been in existence for several decades providing dispatch services via two-way radio such as walkie-talkies. For a number of years now PTT services have been available for use over mobile phone networks. These mobile PTT services have occupied a niche market with business users and have been provided on proprietary networks that do not enable roaming.

Over the past year there has been an explosion of interest in the concept of PTT provided over mobile networks using Internet Protocol (IP) technology. This service uses cellular access and radio resources more efficiently than circuit-switched cellular …

Enhancement Of Linear Prediction Coefficient Quantisation In The 3g Adaptive Multi Rate Speech Coder, John Raymond Mccarthy

Theses

Most speech coding algorithms in use today utilise the source-filter model of human speech production in which speech is modelled as the response of a time varying, linear, all-pole, synthesis filter to an input excitation. In mobile communications, it is the coefficients of this filter and details of the excitation that are transmitted. The filter coefficients are first quantised using a limited number of bits. Due to coefficient sensitivity, direct quantisation of the filter coefficients may lead to an unstable filter during speech synthesis at the receiver and hence an alternative representation is needed. Line Spectral Frequencies (LSFs) have evolved …

General Interference Suppression Technique For Diversity Wireless Rece, Tianyu Yang

Electronic Theses and Dissertations

The area of wireless transceiver design is becoming increasingly important due to the rapid growth of wireless communications market as well as diversified design specifications. Research efforts in this area concentrates on schemes that are capable of increasing the system capacity, providing reconfigurability/reprogrammability and reducing the hardware complexity. Emerging topics related to these goals include Software Defined Radio, Multiple-Input-Multiple-Output (MIMO) Systems, Code Division Multiple Access, Ultra-Wideband Systems, etc. This research adopts space diversity and statistical signal processing for digital interference suppression in wireless receivers. The technique simplifies the analog front-end by eliminating the anti-aliasing filters and relaxing the requirements for …

Modified Sierpinski Fractal Antenna, Tripti Luintel

Electronic Theses and Dissertations

Fractal antennas have the potential to provide multi-band solution through the property of self similarity that the fractal shape possess. This thesis deals with some modifications of the original Sierpinski fractal patch antenna, providing additional parameters to optimize in order to get the required radiation characteristics. A systematic study of the original Sierpinski monopole was done to gain an insight on the operation and multi-band behavior of the antenna and a similar study was done to find out why the patch version of Sierpinski lacks multi-band behavior. A Sierpinski antenna is designed by merging a grid and the fractal restoring …

Evaluation Of A Microwave Radiative Transfer Model For Calculating Sat, Simonetta Thompson

Electronic Theses and Dissertations

Remote sensing is the process of gathering and analyzing information about the earth's ocean, land and atmosphere using electromagnetic "wireless" techniques. Mathematical models, known as Radiative Transfer Models (RTM), are developed to calculate the observed radiance (brightness temperature) seen by the remote sensor. The RTM calculated brightness temperature is a function of fourteen environmental parameters, including atmospheric profiles of temperature, pressure and moisture, sea surface temperature, and cloud liquid water. Input parameters to the RTM model include data from NOAA Centers for Environmental Prediction (NCEP), Reynolds weekly Sea Surface Temperature and National Ocean Data Center (NODC) WOA98 Ocean Salinity and …

Fpga-Based Design Of A Maximum-Power-Point Tracking System For Space A, Todd Persen

Electronic Theses and Dissertations

Satellites need a source of power throughout their missions to help them remain operational for several years. The power supplies of these satellites, provided primarily by solar arrays, must have high efficiencies and low weights in order to meet stringent design constraints. Power conversion from these arrays is required to provide robust and reliable conversion which performs optimally in varying conditions of peak power, solar flux, and occlusion conditions. Since the role of these arrays is to deliver power, one of the principle factors in achieving maximum power output from an array is tracking and holding its maximum-power point. This …

Low Power Cmos Circuit Design And Reliability Analysis For Wireless Me, Md Anwar Sadat

Electronic Theses and Dissertations

A sensor node 'AccuMicroMotion' is proposed that has the ability to detect motion in 6 degrees of freedom for the application of physiological activity monitoring. It is expected to be light weight, low power, small and cheap. The sensor node may collect and transmit 3 axes of acceleration and 3 axes of angular rotation signals from MEMS transducers wirelessly to a nearby base station while attached to or implanted in human body. This dissertation proposes a wireless electronic system-on-a-single-chip to implement the sensor in a traditional CMOS process. The system is low power and may operate 50 hours from a …

Hybrid And Hierarchical Image Registration Techniques, Dongjiang Xu

Electronic Theses and Dissertations

A large number of image registration techniques have been developed for various types of sensors and applications, with the aim to improve the accuracy, computational complexity, generality, and robustness. They can be broadly classified into two categories: intensity-based and feature-based methods. The primary drawback of the intensity-based approaches is that it may fail unless the two images are misaligned by a moderate difference in scale, rotation, and translation. In addition, intensity-based methods lack the robustness in the presence of non-spatial distortions due to different imaging conditions between images. In this dissertation, the image registration is formulated as a two-stage hybrid …