Adaptive Antenna Transmission Power Control for Wireless Forward Link Data Services
| Autor: | Hui-Chen Hsieh, 謝慧珍 |
|---|---|
| Rok vydání: | 2005 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 93 In cellular networks, wireless service coverage is improved through partly radio coverage overlays between neighboring access point transmitters (APTs). For wireless forward link data services, the overlay provides virtual soft handoff opportunities, but also introduces significant intercell interference which reduces feasible service data rate. In this thesis, we investigate APT power level control strategy for wireless forward link data services. We assume that the transmission power of each APT is adjustable between a default high level and a low level if necessary. The objective is not only to improve system throughput by reducing intercell interference but also to adapt APT power level activity to alleviate the impact of temporal and spatial traffic variation among cells. These are achieved by utilizing a simple search-and-lock algorithm which coordinates APT power level activity essentially according to traffic loads and traffic spatial distributions. Moreover, we consider that the frequency of switching APT power levels is an important measure of system complexity. We then propose a hysteresis approach using two thresholds to damp down the frequency of changing APT power activity patterns besides using a single threshold. In addition, we study the effect of adapting APT power level activity on the behavior of the proportional fair scheduler for forward link data services. Our study shows that proposed power level control strategies are able to yield many favorable performance features in terms of throughput, latency, temporal and spatial traffic hot spot relief, in particular when path loss exponent is small or traffic loads are distributed increasingly toward cell boundaries. Additionally, service opportunities by the proportional fair scheduler drift toward users in the far field where fading gains from changing antenna power patterns are more significant. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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