adio signal path 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 gain. We expect to have significant handoff activity between any pair of cells sectors sharing a line on this cookie-cutter map, no matter how short that line is. We can start building a handoff neighbor list from this map by going around each cell sector and noting all the other cell sectors that share a common border. The list neighbors on the map is a starting list of handoff neighbors for the system. As a rough estimate, we expect to see more handoff activity between two sectors when the border line on the map is longer. The question arises what to do if the line on the map between two sectors is very short or if two sectors meet in just a corner. The first thing to do when this happens is to rethink the cell layout and sector plan because this only happens when there are four or more sectors with nearly equal paths. A four-way zone is a candidate for pilot pollu- tion and inefficient use of the CDMA radio resource. If we cannot fix the four-way zone in the layout process, then we probably should put any pair of sectors sharing a line in common on each other's handoff neighbor lists. The map process relies on distance to estimate radio signal path gain. Of course, there are many other factors to consider, such as terrain, vegetation, and buildings. These other factors can create a more favorable radio path environment for one cell over another and move the boundary between two cells. However, this effect is not likely to change the picture so much that two cells that look like neighbors on the map are not neighbors in the radio environment. However, the opposite can happen. Two cells that do not look like neighbors on the map may share radio traffic as a result of propagation irregularities. We can use planning too