Microcell engineering in CDMA cellular networks

The demand for cellular radio services is growing rapidly, and in heavily populated areas the need arises to shrink the cell sizes and “scale” the clustering pattern. The extension of the service into the PCN domain, mostly in-buildings and in pedestrian areas, further enhances this trend. The vision of the “third generation” cellular systems incorporates micro- and picocells for pedestrian use, with macrocells for roaming mobiles. Connectivity between all these cells, while maximizing total system capacity, is the main challenge facing the “third generation architects.” The CDMA cellular system, which shares the same frequency channel across the system (reuse pattern of one) and applies soft handoff between the cells, has already shown, both by analysis and by tests, to have full connectivity between the microcells and the overlaying macrocells without capacity degradation. The parameters involved in the engineering of a heterogeneous CDMA network are discussed in the paper. Factors that determine the size of the cell, the soft handoff zone, and the capacity of the cell clusters are analyzed, and engineering techniques for overlay-underlay cell clustering are outlined