ell, the longer it will be before continuing growth compels us to relieve it again. It is important, however, to keep system issues in mind when splitting cells for traf- fic relief. In particular, having four- and five-way zones of nearly equal radio paths causes pilot pollution and degrades CDMA capacity, as discussed in Sec. 32.1. Since we are adding cells specifically to improve CDMA capacity, we do not want to compromise this mission by adding cells that create low-capacity zones, as discussed in Sec. 32.3. The best way to maintain a CDMA system relatively free of pilot pollution is to main- tain a regular cell grid. Adding cells in hot spots without regard for the grid structure causes four-way zones of pilot pollution to appear, as shown in Fig. 32.3. In Fig. 32.1 we showed how the grid has no areas with more than three cells competing for CDMA capacity. The regular hexagonal grid keeps the three-way zones far apart so that vari- ation in radio propagation does not often bring them together into four-way zones. We can add a cell in the triple-point of three existing cells to form a geometric pic- ture like Fig. 32.5. The reality of a three-to-one split, however, looks more like Fig. 32.6 with three new four-way zones of pilot pollution. Eventually, the new grid fills in and forms a new hexagonal grid with three times as many cells handling three times the traffic, as shown in Fig. 27.15, but the boundary of the new grid is bristling with pilot- pollution zones. Even though the three-to-one split looks tempting, we recommend us- ing the four-to-one split to maintain the grid and to keep pilot pollution to a minimum. The four-to-one split adds a cell midway between two cells. The new cell, as drawn in Fig. 32.7, is one-quarter the size of the old cells. As we continue to split cells in the four-to-one configuration, we end up with a denser grid of cells one-fourth the area han- dling four times the traffic, as shown in Fig. 27.14. The initial new cell is actually a more rectangular shape, as shown in Fig. 32