 they are at their maximum configura- tion, we should identify cells with high blocking rates as high-urgency candidates for cell splitting. We should anticipate growth as well. If the distribution of traffic driven by subscriber demand has a large fraction close to the maximum capacity, then it is only a matter of some more growth before that cell sector is going to have high peak-hour blocking. Our power-level observations are telling us which cells are medium-urgency candidates for cell splitting. We can use the planning models described in Sec. 48.1 to estimate the demand loads and traffic distributions on our existing cells. These forecast demands can tell us when Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Adding Cells to a CDMA System Adding Cells to a CDMA System we expect to reach overload on our existing cells. The predictions identify cells where we expect high blocking in the near future, and these cells are also medium-urgency candidates for cell splitting. 42.3 Keeping the Grid We have identified those cells and cell sectors in greatest need of capacity relief, and we have equipped their base stations with as much capacity-enhancing equipment as we can. We are going to add new cells to the system to serve traffic so that these iden- tified cells will have less traffic. The new cells will take big bites from the service re- gions of the old cells. Because sectors of a cell interfere with each other, reduction of any sector traffic on a cell causes significant relief to the entire cell. We want to select new base station sites to provide the maximum relief for the old cells. As we compile a list of candidate locations for new base stations, we want these new cells to take the biggest bites they can from the old-cell areas to provide the great- est level of traffic relief. The more we relieve and reduce the traffic on a busy c