Adaptive antenna power level control for wireless forward link data services

Abstract

In cellular networks, wireless service coverage improves through partly radio coverage overlaps between neighboring base station transmitters (BSTs). For wireless forward link data services, the overlap provides virtual soft handoff opportunities, but also introduces significant intercell interference which reduces feasible service data rates. In this paper, we investigate adaptive BST power level control strategies for wireless forward link data services. We assume that the transmission power of BST 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 BST power level activities to relieve the impact of temporal and spatial traffic variations among cells. These are achieved by utilizing a simple search-and-lock algorithm which coordinates BST power level activities essentially according to traffic loads and traffic spatial distributions. Moreover, we consider that the frequency of switching BST power levels is an important factor in system design complexity. We then propose a hysteresis approach using two thresholds to damp down the frequency. 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