Performance Study on the Effects of Cell-Breathing in WCDMA

The performance of CDMA cellular systems over the air is generally interference-limited. A phenomena arising from this is the effect of cell-breathing in 3G cellular systems. Cell-breathing is the expansion or contraction of the effective coverage of a cell in response to the number of active mobiles (MSs) in a network. If it is not well controlled, communication failure may result. With 3G offering different classes of services, planning and dimensioning of such high-quality radio networks thus requires extensive planning tools. Despite the progressive rolling out of 3G systems worldwide, the effects of cell-breathing are not well understood. In this work, a simulator is set up to study the effect of cell breathing. Simulation results show how the area where reliable coverage can be provided by a base station (BS) may varies as the density of MSs changes within it. Current work emphasizes on the downlink simulation with a single BS followed by a similar simulation involving 2 BS. The results demonstrate how cell-breathing may cause communications failure.