No description available.

No description available.

Future generation wireless networks are envisioned to provide ubiquitous networking to a wide number of mobile users, promising them the ability to access the various data networks anywhere and anytime. Such networks have motivated the research into efficient management and allocation of the wireless network's limited resources. Heterogeneity also exists amongst the subscribers, i.e. there are those who are willing to spend a little extra on their subscriptions in the prospect of obtaining a better level of service. This work proposes a framework for efficient resource management, while satisfying the heterogeneous QoS demands of the different subscribers. Part of the proposed framework was used to generate mathematical models for the purpose of analyzing the behavior of the system under two different resource management schemes. / February 2006

Orthogonal variable spreading factor (OVSF) code is used in WCDMA system to provide variable service data rates. However, most researches focus on decreasing the number of code assignment without considering how to manage bandwidth with properties of OVSF code. In this research, we propose a dynamic bandwidth borrowing algorithm for quality of service (QoS) supported in the OVSF-CDMA system. When a new call arrives or a current serviced call requests a higher data rate, but the system can not provide the required bandwidth, the borrowing algorithm can be activated to borrow bandwidth from current serviced calls. Also, a dynamic bandwidth reserved algorithm is proposed to avoid forced termination caused by the suddenly increasing bandwidth requirements of current serviced calls. Simulation results show that the value of throughput increases and the QoS of current serviced calls can be maintained.

The loop bandwidth of a fractional-N PLL is a desirable parameter for many applications. A wide bandwidth allows a significant attenuation of phase noise arising from the VCO. A good VCO typically requires a high Q LC oscillator. It is difficult to build an on-chip inductor with a high Q factor. In addition, a good VCO also requires a lot of power. Both these design challenges are relaxed with a wide loop bandwidth PLL. However a wide loop bandwidth reduces the effective oversampling ratio (OSR) between the update rate and loop bandwidth and makes quantization noise from the ΔΣ modulator a much bigger noise contributor. A wide band loop also makes the noise and linearity performance of the phase detector more significant. The key to successful implementation of a wideband fractional-N synthesizer is in managing jitter and spurious performance. In this dissertation we present a new PLL architecture for bandwidth extension or phase noise reduction. By using clock squaring buffers with built-in offsets, multiple clock edges are extracted from a single cycle of a sinusoidal reference and used for phase updates, effectively forming a reference frequency multiplier. A higher update rate enables a higher OSR which allows for better quantization noise shaping and makes a wideband fractional-N PLL possible. However since the proposed reference multiplier utilizes the magnitude information from a sinusoidal reference to obtain phases, the derived new edges tend to cluster around the zero-crossings and form an irregular clock. This presents a challenge in lock acquisition. We have demonstrated for the first time that an irregular clock can be used to lock a PLL. The irregularity of the reference clock is taken into account in the divider by adding a cyclic divide pattern along with the ΔΣ control bits, this forces the loop to locally match the incoming patterns and achieve lock. Theoretically this new architecture allows for a 6x increase in loop BW or a 24dB improvement in phase noise. One potential issue associated with the proposed approach is the degraded spurious performance due to PVT variations, which lead to unintended mismatches between the irregular period and the divider pattern. A calibration scheme was invented to overcome this issue. In simulation, the calibration scheme was shown to lower the spurs down to inherent spurs level, of which the total energy is much less than the integrated phase noise. A test chip for proof of concept is presented and measurements are carefully analyzed. / text

No description available.

Future generation wireless networks are envisioned to provide ubiquitous networking to a wide number of mobile users, promising them the ability to access the various data networks anywhere and anytime. Such networks have motivated the research into efficient management and allocation of the wireless network's limited resources. Heterogeneity also exists amongst the subscribers, i.e. there are those who are willing to spend a little extra on their subscriptions in the prospect of obtaining a better level of service. This work proposes a framework for efficient resource management, while satisfying the heterogeneous QoS demands of the different subscribers. Part of the proposed framework was used to generate mathematical models for the purpose of analyzing the behavior of the system under two different resource management schemes.

Future generation wireless networks are envisioned to provide ubiquitous networking to a wide number of mobile users, promising them the ability to access the various data networks anywhere and anytime. Such networks have motivated the research into efficient management and allocation of the wireless network's limited resources. Heterogeneity also exists amongst the subscribers, i.e. there are those who are willing to spend a little extra on their subscriptions in the prospect of obtaining a better level of service. This work proposes a framework for efficient resource management, while satisfying the heterogeneous QoS demands of the different subscribers. Part of the proposed framework was used to generate mathematical models for the purpose of analyzing the behavior of the system under two different resource management schemes.

Reconfigurable antennas represent a recent innovation in antenna design that changes from classical fixed-form, fixed-function antennas to modifiable structures that can be adapted to fit the requirements of a time varying system. Advances in microwave semiconductor processing technologies have enabled the use of compact, ultra-high quality RF and microwave switches in novel aspects of antenna design. This dissertation introduces the concept of reconfigurable antenna bandwidth control and how advances in switch technology have made these designs realizable. Specifically, it details the development of three new antennas capable of reconfigurable bandwidth control. The newly developed antennas include the reconfigurable ring patch, the reconfigurable planar inverted-F and the reconfigurable parasitic folded dipole. The relevant background work to these designs is described and then design details along with computer simulations and measured experimental results are given. / Ph. D.

In our technological society, the growth of applications is not always followed by the growth of network capacity. There is an increasing demand of bandwidth which cannot always be answered properly. It is especially true in wireless networks such as 3G. Mobile devices can store and use more and more applications which are all using the bandwidth without any control. The Internet experience for the end user can thus be quickly degraded. In this respect, my objective in this thesis is to fill the gap on this matter by implementing a traffic shaping software working on Android devices. In order to get the necessary knowledge to create such an application, series of tests are conducted on similar software based on Windows 7. The outcome of this research is my own solution to shape the traffic on Android mobile devices. The software allows the end user to choose which of his applications should get a higher priority to improve his overall experience with them.